Language：English   Publishing type：Research paper (scientific journal)  

Kidney ischemia-reperfusion injury is a major cause of acute kidney injury (AKI). Following reduced kidney perfusion, the pathological overproduction of reactive oxygen and reactive nitrogen species play a substantial role in the development of kidney ischemia-reperfusion injury. Arginase 2 (ARG2) competes with nitric oxide synthase for the same substrate, L-arginine, and is implicated in the regulation of reactive nitrogen species. Therefore, we investigated the role of ARG2 in kidney ischemia-reperfusion injury using human proximal tubule cells (HK-2) and a mouse model of kidney ischemia-reperfusion injury. ARG2 was predominantly expressed in kidney tubules of the cortex, which was increased after ischemia-reperfusion injury. In HK-2 cells, ARG2 was expressed in punctate form in the cytoplasm and upregulated after hypoxia-reoxygenation. ARG2 knockdown reduced the level of reactive oxygen species and 3-nitrotyrosine after hypoxia-reoxygenation injury compared with control siRNA. Consistent with these results, in Arg2 knockout mice, abnormal kidney function and the increased acute tubular necrosis score induced by ischemia-reperfusion injury was significantly reduced without any obvious blood pressure changes. Additionally, an accumulation of 3-nitrotyrosine and apoptosis of renal tubule cells were attenuated in Arg2 knockout mice compared with wild-type mice. Inhibition of arginase by Nω-hydroxy-nor-L-arginine alleviated kidney ischemia-reperfusion injury like the results found in Arg2 knockout mice. Thus, ARG2 plays a pivotal role in ischemia-reperfusion-induced AKI by means of nitrosative stress. Hence, an ARG2-specific inhibitor may effectively treat kidney ischemia-reperfusion injury.

DOI： 10.1016/j.kint.2020.03.032

Language：English   Publishing type：Research paper (scientific journal)  

Kidney ischemia–reperfusion injury is a major cause of acute kidney injury (AKI). Following reduced kidney perfusion, the pathological overproduction of reactive oxygen and reactive nitrogen species play a substantial role in the development of kidney ischemia–reperfusion injury. Arginase 2 (ARG2) competes with nitric oxide synthase for the same substrate, L-arginine, and is implicated in the regulation of reactive nitrogen species. Therefore, we investigated the role of ARG2 in kidney ischemia–reperfusion injury using human proximal tubule cells (HK-2) and a mouse model of kidney ischemia–reperfusion injury. ARG2 was predominantly expressed in kidney tubules of the cortex, which was increased after ischemia–reperfusion injury. In HK-2 cells, ARG2 was expressed in punctate form in the cytoplasm and upregulated after hypoxia–reoxygenation. ARG2 knockdown reduced the level of reactive oxygen species and 3-nitrotyrosine after hypoxia–reoxygenation injury compared with control siRNA. Consistent with these results, in Arg2 knockout mice, abnormal kidney function and the increased acute tubular necrosis score induced by ischemia–reperfusion injury was significantly reduced without any obvious blood pressure changes. Additionally, an accumulation of 3-nitrotyrosine and apoptosis of renal tubule cells were attenuated in Arg2 knockout mice compared with wild-type mice. Inhibition of arginase by Nω-hydroxy-nor-L-arginine alleviated kidney ischemia–reperfusion injury like the results found in Arg2 knockout mice. Thus, ARG2 plays a pivotal role in ischemia–reperfusion-induced AKI by means of nitrosative stress. Hence, an ARG2-specific inhibitor may effectively treat kidney ischemia–reperfusion injury.

DOI： 10.1016/j.kint.2020.03.032

Language：English   Publishing type：Research paper (scientific journal)  

Genomewide association studies have shown that a nonsynonymous single nucleotide polymorphism in PRKCH is associated with cerebral infarction and atherosclerosis-related complications. We examined the role of PKCη in lipid metabolism and atherosclerosis using apolipoprotein E-deficient (Apoe-/- ) mice. PKCη expression was augmented in the aortas of mice with atherosclerosis and exclusively detected in MOMA2-positive macrophages within atherosclerotic lesions. Prkch+/+ Apoe-/- and Prkch-/- Apoe-/- mice were fed a high-fat diet (HFD), and the dyslipidemia observed in Prkch+/+ Apoe-/- mice was improved in Prkch-/- Apoe-/- mice, with a particular reduction in serum LDL cholesterol and phospholipids. Liver steatosis, which developed in Prkch+/+ Apoe-/- mice, was improved in Prkch-/- Apoe-/- mice, but glucose tolerance, adipose tissue and body weight, and blood pressure were unchanged. Consistent with improvements in LDL cholesterol, atherosclerotic lesions were decreased in HFD-fed Prkch-/- Apoe-/- mice. Immunoreactivity against 3-nitrotyrosine in atherosclerotic lesions was dramatically decreased in Prkch-/- Apoe-/- mice, accompanied by decreased necrosis and apoptosis in the lesions. ARG2 mRNA and protein levels were significantly increased in Prkch-/- Apoe-/- macrophages. These data show that PKCη deficiency improves dyslipidemia and reduces susceptibility to atherosclerosis in Apoe-/- mice, showing that PKCη plays a role in atherosclerosis development.

DOI： 10.1111/gtc.12402

Language：English   Publishing type：Research paper (scientific journal)  

Genomewide association studies have shown that a nonsynonymous single nucleotide polymorphism in PRKCH is associated with cerebral infarction and atherosclerosis-related complications. We examined the role of PKCη in lipid metabolism and atherosclerosis using apolipoprotein E-deficient (Apoe^−/−) mice. PKCη expression was augmented in the aortas of mice with atherosclerosis and exclusively detected in MOMA2-positive macrophages within atherosclerotic lesions. Prkch^+/+Apoe^−/− and Prkch^−/−Apoe^−/− mice were fed a high-fat diet (HFD), and the dyslipidemia observed in Prkch^+/+Apoe^−/− mice was improved in Prkch^−/−Apoe^−/− mice, with a particular reduction in serum LDL cholesterol and phospholipids. Liver steatosis, which developed in Prkch^+/+Apoe^−/− mice, was improved in Prkch^−/−Apoe^−/− mice, but glucose tolerance, adipose tissue and body weight, and blood pressure were unchanged. Consistent with improvements in LDL cholesterol, atherosclerotic lesions were decreased in HFD-fed Prkch^−/−Apoe^−/− mice. Immunoreactivity against 3-nitrotyrosine in atherosclerotic lesions was dramatically decreased in Prkch^−/−Apoe^−/− mice, accompanied by decreased necrosis and apoptosis in the lesions. ARG2 mRNA and protein levels were significantly increased in Prkch^−/−Apoe^−/− macrophages. These data show that PKCη deficiency improves dyslipidemia and reduces susceptibility to atherosclerosis in Apoe^−/− mice, showing that PKCη plays a role in atherosclerosis development.

DOI： 10.1111/gtc.12402

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The physiological role of autophagic flux within the vascular endothelial layer remains poorly understood. Here, we show that in primary endothelial cells, oxidized and native LDL stimulates autophagosome formation. Moreover, by both confocal and electron microscopy, excess native or modified LDL appears to be engulfed within autophagic structures. Transient knockdown of the essential autophagy gene ATG7 resulted in higher levels of intracellular (125) I-LDL and oxidized LDL (OxLDL) accumulation, suggesting that in endothelial cells, autophagy may represent an important mechanism to regulate excess, exogenous lipids. The physiological importance of these observations was assessed using mice containing a conditional deletion of ATG7 within the endothelium. Following acute intravenous infusion of fluorescently labeled OxLDL, mice lacking endothelial expression of ATG7 demonstrated prolonged retention of OxLDL within the retinal pigment epithelium (RPE) and choroidal endothelium of the eye. In a chronic model of lipid excess, we analyzed atherosclerotic burden in ApoE(-/-) mice with or without endothelial autophagic flux. The absence of endothelial autophagy markedly increased atherosclerotic burden. Thus, in both an acute and chronic in vivo model, endothelial autophagy appears critically important in limiting lipid accumulation within the vessel wall. As such, strategies that stimulate autophagy, or prevent the age-dependent decline in autophagic flux, might be particularly beneficial in treating atherosclerotic vascular disease.

DOI： 10.1111/acel.12423

Language：English   Publishing type：Research paper (scientific journal)  

Endothelial secretion of von Willebrand factor (VWF) from intracellular organelles known as Weibel-Palade bodies (WPBs) is required for platelet adhesion to the injured vessel wall. Here we demonstrate that WPBs are often found near or within autophagosomes and that endothelial autophagosomes contain abundant VWF protein. Pharmacological inhibitors of autophagy or knockdown of the essential autophagy genes Atg5 or Atg7 inhibits the in vitro secretion of VWF. Furthermore, although mice with endothelial-specific deletion of Atg7 have normal vessel architecture and capillary density, they exhibit impaired epinephrine-stimulated VWF release, reduced levels of high-molecular weight VWF multimers and a corresponding prolongation of bleeding times. Endothelial-specific deletion of Atg5 or pharmacological inhibition of autophagic flux results in a similar in vivo alteration of hemostasis. Thus, autophagy regulates endothelial VWF secretion, and transient pharmacological inhibition of autophagic flux may be a useful strategy to prevent thrombotic events.

DOI： 10.1038/nm.3288

Language：English   Publishing type：Research paper (scientific journal)  

Endothelial secretion of von Willebrand factor (VWF) from intracellular organelles known as Weibel-Palade bodies (WPBs) is required for platelet adhesion to the injured vessel wall. Here we demonstrate that WPBs are often found near or within autophagosomes and that endothelial autophagosomes contain abundant VWF protein. Pharmacological inhibitors of autophagy or knockdown of the essential autophagy genes Atg5 or Atg7 inhibits the in vitro secretion of VWF. Furthermore, although mice with endothelial-specific deletion of Atg7 have normal vessel architecture and capillary density, they exhibit impaired epinephrine-stimulated VWF release, reduced levels of high-molecular weight VWF multimers and a corresponding prolongation of bleeding times. Endothelial-specific deletion of Atg5 or pharmacological inhibition of autophagic flux results in a similar in vivo alteration of hemostasis. Thus, autophagy regulates endothelial VWF secretion, and transient pharmacological inhibition of autophagic flux may be a useful strategy to prevent thrombotic events.

DOI： 10.1038/nm.3288

Language：English   Publishing type：Research paper (scientific journal)  

We cloned cDNA and genomic DNA containing exon 1 of mouse Neil3. Neil3 spans 52.4 kb and consists of 10 exons. Northern blot analysis revealed that Neil3 mRNA was selectively expressed in thymus, spleen and bone marrow. High levels of Neil3 mRNA were also detected in various mouse B cell lines by RT-PCR. Immunofluorescence microscopy using anti-NEIL3 revealed that recombinant mouse NEIL3 is localized in the nuclei. In mouse splenocytes, the level of Neil3 mRNA significantly increased after mitogen stimulation in vitro. We established NEIL3-null mice, which are viable and fertile. We found candidate sequences for NEIL3 orthologues in a DNA database from dog and zebrafish in addition to human and mouse, but not invertebrates. NEIL3 may function exclusively in vertebrates, such as mammals.

DOI： 10.1093/jb/mvi168

Language：English   Publisher：Clinical and Experimental Nephrology  

Background: Encapsulated peritoneal sclerosis (EPS) is a serious complication in patients undergoing peritoneal dialysis (PD). Neutral-pH dialysate is associated with less peritoneal damage and a lower incidence of EPS than conventional PD solution. However, monitoring for peritoneal damage and predicting EPS remain important during PD therapy. Methods: We measured the mesothelial cell area, dialysate-to-plasma ratio of creatinine after 4 h, and concentrations of the potential biological markers effluent fibrin degradation products (eFDPs), cancer antigen-125, and interleukin-6 in the effluent dialysate from patients who had been undergoing PD therapy for > 5 years in our hospital. These biomarkers were obtained from the drainage fluid of the final measurement of peritoneal equilibration testing before withdrawal from PD therapy. The concentrations of these potential biomarkers were measured in 39 patients who withdrew from PD therapy and were enrolled in the study. Results: Three participants developed EPS after withdrawing PD. The dialysate-to-plasma ratio of creatinine, area of mesothelial cells, and interleukin-6 appearance rate in participants who developed EPS tended to be higher than those in patients who did not, but there were no significant differences. Significantly more eFDPs were in participants who developed EPS than in those who did not (138.5 ± 15.1 vs. 32.9 ± 7.4 µg/mL, P = 0.002). There was no difference in the cancer antigen-125 appearance rate between the groups. A cut-off value of eFDPs ≥ 119.1 µg/mL was optimal for predicting EPS (P = 0.006, specificity = 0.972, sensitivity = 1.000). Conclusion: This study shows that eFDPs may be a useful biological marker for predicting EPS in patients undergoing PD using neutral-pH dialysate.

DOI： 10.1007/s10157-024-02565-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Scientific Reports  

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been shown to be renoprotective in ischemia-reperfusion (I/R) injury, with several proposed mechanisms, though additional mechanisms likely exist. This study investigated the impact of luseogliflozin on kidney fibrosis at 48 h and 1 week post I/R injury in C57BL/6 mice. Luseogliflozin attenuated kidney dysfunction and the acute tubular necrosis score on day 2 post I/R injury, and subsequent fibrosis at 1 week, as determined by Sirius red staining. Metabolomics enrichment analysis of I/R-injured kidneys revealed suppression of the glycolytic system and activation of mitochondrial function under treatment with luseogliflozin. Western blotting showed increased nutrient deprivation signaling with elevated phosphorylated AMP-activated protein kinase and Sirtuin-3 in luseogliflozin-treated kidneys. Luseogliflozin-treated kidneys displayed increased protein levels of carnitine palmitoyl transferase 1α and decreased triglyceride deposition, as determined by oil red O staining, suggesting activated fatty acid oxidation. Luseogliflozin prevented the I/R injury-induced reduction in nuclear factor erythroid 2-related factor 2 activity. Western blotting revealed increased glutathione peroxidase 4 and decreased transferrin receptor protein 1 expression. Immunostaining showed reduced 4-hydroxynonenal and malondialdehyde levels, especially in renal tubules, indicating suppressed ferroptosis. Luseogliflozin may protect the kidney from I/R injury by inhibiting ferroptosis through oxidative stress reduction.

DOI： 10.1038/s41598-024-71416-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Arteriosclerosis, Thrombosis, and Vascular Biology  

BACKGROUND: Hyponatremia, frequently observed in patients with chronic kidney disease, is associated with increased cardiovascular morbidity and mortality. Hyponatremia or low osmolality induces oxidative stress and cell death, both of which accelerate vascular calcification (VC), a critical phenotype in patients with chronic kidney disease. Whether hyponatremia or low osmolality plays a role in the pathogenesis of VC is unknown. METHODS: Human vascular smooth muscle cells (VSMCs) and mouse aortic rings were cultured in various osmotic conditions and calcifying medium supplemented with high calcium and phosphate. The effects of low osmolality on phenotypic change and oxidative stress in the cultured VSMCs were examined. Microarray analysis was conducted to determine the main signaling pathway of osmolality-related VC. The transcellular sodium and calcium ions flux across the VSMCs were visualized by live imaging. Furthermore, the effect of osmolality on calciprotein particles (CPPs) was investigated. Associations between arterial intimal calcification and hyponatremia or low osmolality were examined by a cross-sectional study using human autopsy specimens obtained in the Hisayama Study. RESULTS: Low osmolality exacerbated calcification of the ECM (extracellular matrix) of cultured VSMCs and mouse aortic rings. Oxidative stress and osteogenic differentiation of VSMCs were identified as the underlying mechanisms responsible for low osmolality-induced VC. Microarray analysis showed that low osmolality activated the Rac1 (Ras-related C3 botulinum toxin substrate 1)-Akt pathway and reduced NCX1 (Na-Ca exchanger 1) expression. Live imaging showed synchronic calcium ion efflux and sodium ion influx via NCX1 when extracellular sodium ion concentrations were increased. An NCX1 inhibitor promoted calcifying media-induced VC by reducing calcium ion efflux. Furthermore, low osmolality accelerated the generation and maturation steps of CPPs. The cross-sectional study of human autopsy specimens showed that hyponatremia and low osmolality were associated with a greater area of arterial intimal calcification. CONCLUSIONS: Hyponatremia and low osmolality promote VC through multiple cellular processes, including the Rac1-Akt pathway activation.

DOI： 10.1161/ATVBAHA.123.320069

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DOI： 10.6084/m9.figshare.26211134

Language：English   Publisher：Nature Publishing Group  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Hypertension Research  

We previously reported that brain atrophy was more severe and progressed more rapidly in patients with end-stage kidney disease on peritoneal dialysis (PD) than those with non-dialysis-dependent chronic kidney disease. However, it remains unknown whether there is a difference between patients on PD and hemodialysis (HD). In total, 73 PD and 34 HD patients who underwent brain magnetic resonance imaging (MRI) were recruited for a cross-sectional analysis. Among them, 42 PD and 25 HD patients who underwent a second brain MRI after 2 years were recruited for a longitudinal analysis. T1-weighted MRI images were analyzed. Total gray matter volume (GMV), total white matter volume, and cerebrospinal fluid volume were segmented, and each volume was quantified using statistical parametric mapping software. The ratio of GMV (GMR) was calculated by dividing GMV by intracranial volume, to adjust for variations in head size. We compared GMR between PD and HD patients in the cross-sectional analysis and the annual change in GMR (AC-GMR) in the longitudinal analysis. In the cross-sectional analysis, age- and sex-adjusted GMR was significantly lower in PD than HD patients [least square mean (LSM): 39.2% vs. 40.0%, P = 0.018]. AC-GMR was significantly greater in PD than HD patients and this difference remained significant even after adjustment for potential confounding factors (LSM: -0.68 vs. -0.28 percentage-points/year, P = 0.011). In conclusion, the present study demonstrated a more rapid progression of brain atrophy in PD patients compared with HD patients. We demonstrated that decline in GMR progressed significantly more rapidly in PD than HD patients independent of potential confounding factors. GMR gray matter volume ratio, HD hemodialysis, PD peritoneal dialysis.

DOI： 10.1038/s41440-023-01530-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Scientific Reports  

Peritoneal calcification is a prominent feature of the later stage of encapsulating peritoneal sclerosis (EPS) in patients undergoing long-term peritoneal dialysis (PD). However, the pathogenesis and preventive strategy for peritoneal calcification remain unclear. Peritoneum samples from EPS patients were examined histologically. Peritoneal calcification was induced in mice by feeding with an adenine-containing diet combined with intraperitoneal administration of lipopolysaccharide and a calcifying solution containing high calcium and phosphate. Excised mouse peritoneum, human mesothelial cells (MeT5A), and mouse embryonic fibroblasts (MEFs) were cultured in calcifying medium. Immunohistochemistry confirmed the appearance of osteoblastic differentiation-marker-positive cells in the visceral peritoneum from EPS patients. Intraperitoneal administration of magnesium suppressed peritoneal fibrosis and calcification in mice. Calcifying medium increased the calcification of cultured mouse peritoneum, which was prevented by magnesium. Calcification of the extracellular matrix was accelerated in Met5A cells and MEFs treated with calcification medium. Calcifying medium also upregulated osteoblastic differentiation markers in MeT5A cells and induced apoptosis in MEFs. Conversely, magnesium supplementation mitigated extracellular matrix calcification and phenotypic transdifferentiation and apoptosis caused by calcifying conditions in cultured MeT5A cells and MEFs. Phosphate loading contributes to the progression of EPS through peritoneal calcification and fibrosis, which can be prevented by magnesium supplementation.

DOI： 10.1038/s41598-023-43657-y

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Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：(一社)日本腎臓学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biochemical and Biophysical Research Communications  

Acute kidney injury is an important global health concern as it is associated with high morbidity and mortality. Polyamines, essential for cell growth and proliferation, are known to inhibit cardiovascular disease. However, under conditions of cellular damage, toxic acrolein is produced from polyamines by the enzyme spermine oxidase (SMOX). We used a mouse renal ischemia-reperfusion model and human proximal tubule cells (HK-2) to investigate whether acrolein exacerbates acute kidney injury by renal tubular cell death. Acrolein visualized by acroleinRED was increased in ischemia-reperfusion kidneys, particularly in tubular cells. When HK-2 cells were cultured under 1% oxygen for 24 h, then switched to 21% oxygen for 24 h (hypoxia-reoxygenation), acrolein accumulated and SMOX mRNA and protein levels were increased. Acrolein induced cell death and fibrosis-related TGFB1 mRNA in HK-2 cells. Administration of the acrolein scavenger cysteamine suppressed the acrolein-induced upregulation of TGFB1 mRNA. Cysteamine also inhibited a decrease in the mitochondrial membrane potential observed by MitoTrackerCMXRos, and cell death induced by hypoxia-reoxygenation. The siRNA-mediated knockdown of SMOX also suppressed hypoxia-reoxygenation-induced acrolein accumulation and cell death. Our study suggests that acrolein exacerbates acute kidney injury by promoting tubular cell death during ischemia-reperfusion injury. Treatment to control the accumulation of acrolein might be an effective therapeutic option for renal ischemia-reperfusion injury.

DOI： 10.1016/j.bbrc.2023.05.029

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Language：Japanese   Publishing type：Research paper (conference, symposium, etc.)   Publisher：(一社)日本腎臓学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers in Cardiovascular Medicine  

BACKGROUND: Patients with chronic kidney disease (CKD) have a high risk of left ventricular hypertrophy (LVH). Fibroblast growth factor 23 (FGF23) and indoxyl sulfate (IS) are associated with LVH in patients with CKD, but the interactions between these molecules remain unknown. We investigated whether IS contributes to LVH associated with FGF23 in cultured cardiomyocytes and CKD mice. METHODS AND RESULTS: In cultured rat cardiac myoblast H9c2 cells incubated with IS, mRNA levels of the LVH markers atrial natriuretic factor, brain natriuretic peptide, and β-myosin heavy chain were significantly upregulated. Levels of mRNA of the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3), which regulates FGF23 O-glycosylation, and FGF23 were also upregulated in H9c2 cells. Intact FGF23 protein expression and fibroblast growth factor receptor 4 (FGFR4) phosphorylation were increased in cell lysates by IS administration. In C57BL/6J mice with heminephrectomy, IS promoted LVH, whereas the inhibition of FGFR4 significantly reduced heart weight and left ventricular wall thickness in IS-treated groups. While there was no significant difference in serum FGF23 concentrations, cardiac FGF23 protein expression was markedly increased in IS-injected mice. GALNT3, hypoxia-inducible factor 1 alpha, and FGF23 protein expression was induced in H9c2 cells by IS treatment and suppressed by the inhibition of Aryl hydrocarbon receptor which is the receptor for IS. CONCLUSION: This study suggests that IS increases FGF23 protein expression via an increase in GALNT3 and hypoxia-inducible factor 1 alpha expression, and activates FGF23-FGFR4 signaling in cardiomyocytes, leading to LVH.

DOI： 10.3389/fcvm.2023.990422

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Background: Patients with chronic kidney disease (CKD) have a high risk of left ventricular hypertrophy (LVH). Fibroblast growth factor 23 (FGF23) and indoxyl sulfate (IS) are associated with LVH in patients with CKD, but the interactions between these molecules remain unknown. We investigated whether IS contributes to LVH associated with FGF23 in cultured cardiomyocytes and CKD mice.

Methods and results: In cultured rat cardiac myoblast H9c2 cells incubated with IS, mRNA levels of the LVH markers atrial natriuretic factor, brain natriuretic peptide, and β-myosin heavy chain were significantly upregulated. Levels of mRNA of the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3), which regulates FGF23 O-glycosylation, and FGF23 were also upregulated in H9c2 cells. Intact FGF23 protein expression and fibroblast growth factor receptor 4 (FGFR4) phosphorylation were increased in cell lysates by IS administration. In C57BL/6J mice with heminephrectomy, IS promoted LVH, whereas the inhibition of FGFR4 significantly reduced heart weight and left ventricular wall thickness in IS-treated groups. While there was no significant difference in serum FGF23 concentrations, cardiac FGF23 protein expression was markedly increased in IS-injected mice. GALNT3, hypoxia-inducible factor 1 alpha, and FGF23 protein expression was induced in H9c2 cells by IS treatment and suppressed by the inhibition of Aryl hydrocarbon receptor which is the receptor for IS.

Conclusion: This study suggests that IS increases FGF23 protein expression via an increase in GALNT3 and hypoxia-inducible factor 1 alpha expression, and activates FGF23-FGFR4 signaling in cardiomyocytes, leading to LVH.

DOI： https://doi.org/10.3389/fcvm.2023.990422

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: The accumulation of glucose degradation products (GDPs) during peritoneal dialysis (PD) can lead to immature angiogenesis in the peritoneum. However, the effect of GDPs on angiogenesis, at concentrations observed in dialysate effluent, has not been widely investigated. We do not know how the inflammation observed in PD-related peritonitis affects angiogenesis of the peritoneum. METHODS: Human umbilical vessel endothelial cells (HUVEC) and human umbilical aortic smooth muscle cells (HUASMC) were used to examine the response to the three main GDPs found in peritoneal dialysate (methylglyoxal (MGO), 3-deoxyglucosone (3-DG), and 5-hydroxymethylfurfural (5-HMF). Supernatant from lipopolysaccharide (LPS)-activated murine macrophage cell lines (RAW 264.7 cells) were used to stimulate angiogenesis in the peritoneum. Changes in the expression of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor B (PDGFB) in HUVEC, and PDGF-receptor beta (PDGF-Rβ) in HUASMC, were examined by real-time PCR, Western blot, and ELISA. RESULTS: In HUVECs, the expression of PDGFB mRNA and protein were decreased by exposure to MGO, 3-DG, and 5-HMF at concentrations observed in dialysate effluent. A subsequent decrease in secreted PDGF-BB was observed. In HUASMCs, MGO and 5-HMF increased the expression of VEGF-A mRNA and protein, while 5-HMF decreased the expression of PDGF-Rβ. VEGF-A is upregulated, and PDGF-Rβ is downregulated, by conditioned medium of LPS-stimulated macrophages in HUASMCs. CONCLUSIONS: The GDPs of PD effluent cause an imbalance of angiogenic factors in endothelial cells and vascular smooth muscle cells that may lead to immature angiogenesis in the peritoneum.

DOI： 10.1007/s10157-022-02272-3

Language：English   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本腎臓学会  

血管内皮細胞と血管平滑筋細胞を用いたin vitro実験系において、腹膜透析液中のグルコース分解物(GDP)が血管新生に及ぼす影響について検討した。ヒト臍帯静脈内皮細胞(HUVEC)とヒト臍帯動脈平滑筋細胞(HUASMC)において、腹膜透析液に含まれる三つの主要なGDPであるメチルグリオキサール(MGO)、3-デオキシグルコソン(3-DG)、5-ヒドロキシメチルフルフラール(5-HMF)の作用を調べた。HUVECとHUASMCはリポポリサッカライド(LPS)で活性化したマウスマクロファージ細胞株の培養上清で刺激した。その結果、HUVECにおいて、血小板由来増殖因子B(PDGFB)のmRNAとタンパク質の発現は、腹膜透析液で観察される濃度のMGO、3-DG、5-HMFへの曝露により低下し、それに続いて分泌されるPDGF受容体βの減少が観察された。HUASMCでは、MGOと5-HMFにより血管内皮増殖因子A(VEGF-A)のmRNAとタンパク質の発現が増加し、5-HMFによりPDGF受容体βの発現が低下した。HUASMCでは、LPS刺激マクロファージの培養上清により、VEGF-Aの発現が亢進し、PDGF受容体βの発現は低下した。以上より、腹膜透析液中のGDPは、血管内皮細胞や血管平滑筋細胞における血管新生因子の不均衡を引き起こし、腹膜における未熟な血管新生を誘導する可能性が示された。

Publisher：Clinical and Experimental Nephrology  

Background: Hypertension is an important prognostic predictor in patients with chronic kidney disease (CKD), and the recommended target blood pressure has been continuously revised. This study aimed to reveal the current antihypertensive practices in Japanese patients with CKD. Methods: In the Fukuoka Kidney disease Registry, we extracted 3664 non-dialysis-dependent patients with CKD. Apparent treatment-resistant hypertension (aTRH) was defined as a failure of blood-pressure control treated with three antihypertensive medication classes or a treatment with ≥ 4 classes regardless of blood pressure. The blood-pressure control complied with the target blood pressure recommended by the KDIGO 2012 guideline. Results: The median age of the patients was 67 years, body mass index (BMI) was 23 kg/m2, and estimated glomerular filtration rate (eGFR) was 40 mL/min/1.73 m2. The number of patients with unachieved blood-pressure control was 1933, of whom 26% received ≥ 3 classes of antihypertensive medications. The first choice of medication was renin–angiotensin system inhibitors, followed by calcium-channel blockers. The rate of thiazide use was low in all CKD stages (3–11%). The prevalence of aTRH was 16%, which was significantly associated with BMI (odds ratio [95% confidence interval] per 1-standard deviation change, 1.38 [1.25–1.53]), decreased eGFR (1.87 [1.57–2.23]), as well as age, diabetes mellitus, and chronic heart disease. Conclusions: Renal dysfunction and obesity are important risk factors of aTRH. Even under nephrologist care, most patients were treated with insufficient antihypertensive medications. It is important to prescribe sufficient classes of antihypertensive medications, including diuretics, and to improve patients’ lifestyle habits.

DOI： 10.1007/s10157-022-02250-9

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Background: The accumulation of glucose degradation products (GDPs) during peritoneal dialysis (PD) can lead to immature angiogenesis in the peritoneum. However, the effect of GDPs on angiogenesis, at concentrations observed in dialysate effluent, has not been widely investigated. We do not know how the inflammation observed in PD-related peritonitis affects angiogenesis of the peritoneum.

Methods: Human umbilical vessel endothelial cells (HUVEC) and human umbilical aortic smooth muscle cells (HUASMC) were used to examine the response to the three main GDPs found in peritoneal dialysate (methylglyoxal (MGO), 3-deoxyglucosone (3-DG), and 5-hydroxymethylfurfural (5-HMF). Supernatant from lipopolysaccharide (LPS)-activated murine macrophage cell lines (RAW 264.7 cells) were used to stimulate angiogenesis in the peritoneum. Changes in the expression of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor B (PDGFB) in HUVEC, and PDGF-receptor beta (PDGF-Rβ) in HUASMC, were examined by real-time PCR, Western blot, and ELISA.

Results: In HUVECs, the expression of PDGFB mRNA and protein were decreased by exposure to MGO, 3-DG, and 5-HMF at concentrations observed in dialysate effluent. A subsequent decrease in secreted PDGF-BB was observed. In HUASMCs, MGO and 5-HMF increased the expression of VEGF-A mRNA and protein, while 5-HMF decreased the expression of PDGF-Rβ. VEGF-A is upregulated, and PDGF-Rβ is downregulated, by conditioned medium of LPS-stimulated macrophages in HUASMCs.

Conclusions: The GDPs of PD effluent cause an imbalance of angiogenic factors in endothelial cells and vascular smooth muscle cells that may lead to immature angiogenesis in the peritoneum.

DOI： 10.1007/s10157-022-02272-3

Language：English   Publishing type：Research paper (scientific journal)  

Cellular phosphate transporters play critical roles in the pathogenesis of vascular calcification (VC) in chronic kidney disease (CKD). However, the mechanistic link between VC and xenotropic and polytropic receptor 1 (XPR1), a newly identified phosphate exporter, remains unknown. We developed a new mouse model with rapidly progressive uremic VC in C57BL/6 mice and examined the roles of XPR1. The combination of surgical heminephrectomy and 8 weeks of feeding a customized warfarin and adenine-based diet induced extensive aortic VC in almost all mice. The XPR1 mRNA level in the aorta of CKD mice was significantly lower than those in control mice as early as week 2, when there was no apparent VC, which progressively declined thereafter. Dietary phosphate restriction increased XPR1 mRNA expression in the aorta but reduced aortic VC in CKD mice. In cultured vascular smooth muscle cells (VSMCs), a calcifying medium supplemented with high phosphate and calcium did not affect XPR1 mRNA expression. The XPR1 mRNA expression in cultured VCMCs was also unaffected by administration of indoxyl sulfate or calcitriol deficiency but was decreased by 1-34 parathyroid hormone or fibroblast growth factor 23 supplementation. Furthermore, XPR1 deletion in the cultured VSMCs exacerbated calcification of the extracellular matrix as well as the osteogenic phenotypic switch under the condition of calcifying medium. Our data suggest that XPR1 plays protective roles in the pathogenesis of VC and its decrease in the aorta may contribute to the progression of VC in CKD.

DOI： 10.1007/s00223-022-00947-3

Language：English   Publishing type：Research paper (scientific journal)  

Cellular phosphate transporters play critical roles in the pathogenesis of vascular calcification (VC) in chronic kidney disease (CKD). However, the mechanistic link between VC and xenotropic and polytropic receptor 1 (XPR1), a newly identified phosphate exporter, remains unknown. We developed a new mouse model with rapidly progressive uremic VC in C57BL/6 mice and examined the roles of XPR1. The combination of surgical heminephrectomy and 8 weeks of feeding a customized warfarin and adenine-based diet induced extensive aortic VC in almost all mice. The XPR1 mRNA level in the aorta of CKD mice was significantly lower than those in control mice as early as week 2, when there was no apparent VC, which progressively declined thereafter. Dietary phosphate restriction increased XPR1 mRNA expression in the aorta but reduced aortic VC in CKD mice. In cultured vascular smooth muscle cells (VSMCs), a calcifying medium supplemented with high phosphate and calcium did not affect XPR1 mRNA expression. The XPR1 mRNA expression in cultured VCMCs was also unaffected by administration of indoxyl sulfate or calcitriol deficiency but was decreased by 1-34 parathyroid hormone or fibroblast growth factor 23 supplementation. Furthermore, XPR1 deletion in the cultured VSMCs exacerbated calcification of the extracellular matrix as well as the osteogenic phenotypic switch under the condition of calcifying medium. Our data suggest that XPR1 plays protective roles in the pathogenesis of VC and its decrease in the aorta may contribute to the progression of VC in CKD.

DOI： 10.1007/s00223-022-00947-3

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CEN case reports  

Dialysate leakage is one of the causes of peritoneal dialysis (PD)-related peritonitis. The rate of catheter removal in PD-related peritonitis caused by dialysate leakage (PDPDL) is high, and the correct treatment is unclear. We experienced a case of PDPDL that was treated with intravenous and intraperitoneal antibiotic therapy. A 44-year-old Japanese man had high glucose discharge from the exit site after 14 days of initiating PD, and he had a fever and cloudy effluent with a high white cell count. We diagnosed him with PDPDL and began to administer vancomycin and ceftazidime intraperitoneally. However, the peritonitis could not be ameliorated. A culture examination showed Staphylococcus aureus from the effluent of peritoneal cavity and exit site cultures. We began intraperitoneal cefazolin administration according to a drug susceptibility test, but the effluent cell count remained high. As we added intravenous cefazolin administration, his symptoms and cloudy effluent improved, and the effluent cell count normalized. He has not developed any recurrence of dialysate leakage or peritonitis. Our findings suggest that PD-related peritonitis accompanied by other infectious sites, such as PDPDL, should be treated with additional intravenous antibiotic therapy to taking effect on the infectious sites except for peritoneum and to keep plasma concentration of antibiotics sufficient especially in cases with preserved residual kidney function.

DOI： 10.1007/s13730-021-00644-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：シュプリンガー・ジャパン(株)  

症例は44歳男性で、腹膜透析開始14日後にダイアライザー出口部で血糖高値を示し、発熱、透析排液混濁、白血球数増加をきたした。透析液漏出に起因する腹膜透析関連腹膜炎と診断し、バンコマイシン(1g/日)およびセフタジジム(1g/日)の腹腔内投与を開始したが、改善は認められなかった。腹腔内および出口部排液の培養検査にて黄色ブドウ球菌を検出し、薬剤感受性試験をもとにセファゾリン(1.5g/日)腹腔内投与を開始したが、排液細胞数は依然として高値を示した。セファゾリン(1g/日)静脈内投与を追加したところ、症状と排液混濁は改善し、排液細胞数は正常化した。腹膜透析開始2年後も透析液漏出または腹膜炎の再発は認めていない。

Language：English   Publishing type：Research paper (scientific journal)  

Women have a longer life expectancy than men in the general population. However, it has remained unclear whether this advantage is maintained in patients undergoing maintenance hemodialysis. The aim of this study was to compare the risk of mortality, especially infection-related mortality, between male and female hemodialysis patients. A total of 3065 Japanese hemodialysis patients aged ≥ 18 years old were followed up for 10 years. The primary outcomes were all-cause and infection-related mortality. The associations between sex and these outcomes were examined using Cox proportional hazards models. During the median follow-up of 8.8 years, 1498 patients died of any cause, 387 of whom died of infection. Compared with men, the multivariable-adjusted hazard ratios (95&#37; confidence interval) for all-cause and infection-related mortality in women were 0.51 (0.45-0.58, P < 0.05) and 0.36 (0.27-0.47, P < 0.05), respectively. These findings remained significant even when propensity score-matching or inverse probability of treatment weighting adjustment methods were employed. Furthermore, even when the non-infection-related mortality was considered a competing risk, the infection-related mortality rate in women was still significantly lower than that in men. Regarding all-cause and infection-related deaths, women have a survival advantage compared with men among Japanese patients undergoing maintenance hemodialysis.

DOI： 10.1038/s41598-021-03551-x

Language：English   Publishing type：Research paper (scientific journal)  

Objective With recent advances in endoscopic modalities, small bowel vascular lesions (SBVLs) are often now detected in patients with gastrointestinal bleeding. Given the high invasiveness of endoscopic treatment, it is important to select patients at high risk for bleeding. To assess the risk of rebleeding in patients with SBVLs as a systemic disease rather than a gastrointestinal disease in relation to their general health. Methods We retrospectively analyzed the clinical data of 55 patients with SBVLs among patients with obscure gastrointestinal bleeding. The possible association between the clinical findings and the updated Charlson comorbidity index with rebleeding was evaluated. Results Gastrointestinal rebleeding occurred in 20 patients (36.4&#37;) during the follow-up period. The presence of multiple comorbidities as indicated by an updated Charlson comorbidity index of ≥4 was a risk factor for rebleeding (hazard ratio, 3.64; p=0.004). Other risk factors were arteriosclerosis of the superior mesenteric artery and multiple SBVLs. Endoscopic hemostasis and the discontinuation of antithrombotic medications were not significantly associated with rebleeding. Patients with a high updated Charlson comorbidity index had a high risk of death of causes other than gastrointestinal rebleeding. Conclusion Gastrointestinal rebleeding is not a rare condition among patients with SBVLs. Patients with poor general health may therefore have a higher risk of rebleeding.

DOI： 10.2169/internalmedicine.6341-20

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: A growing body of evidence has shown that non-alcoholic fatty liver disease (NAFLD) is associated with chronic kidney disease (CKD). Non-invasive fibrosis assessments of NAFLD such as Fibrosis-4 (FIB-4) index and NAFLD fibrosis score (NFS) have been developed to substitute liver biopsy. Little is known about the association between FIB-4 index or NFS and the components of CKD. METHODS: In the present cross-sectional study, we assessed of 3640 Japanese CKD patients. We examined the association between FIB-4index or NFS and the odds of having low estimated glomerular filtration rate (eGFR) defined as eGFR < 60 mL/min/1.73 m2 or albuminuria defined as urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g. Patients were divided into quartiles according to their baseline FIB-4 index and NFS levels. Linear and logistic regression analysis were conducted, with adjustment for potential confounding factors. RESULTS: FIB-4 index and NFS were negatively associated with eGFR, but not UACR, after adjustment for potential confounding factors. Both FIB-4 index and NFS were significantly associated with low eGFR after adjustment for potential confounding factors. Meanwhile, in the multivariable-adjusted model, no associations were found between FIB-4 index or NFS and albuminuria. The addition of FIB-4 index or NFS to the established clinical CKD risk factors improved diagnostic accuracy of prevalence of low eGFR. We also found that there was a significant trend of higher FIB-4 index and NFS with more advanced renal fibrosis using the kidney biopsy data. CONCLUSIONS: Higher non-invasive fibrosis assessments of NAFLD were associated with higher odds of decreased eGFR.

DOI： 10.1007/s10157-020-02018-z

Language：English   Publishing type：Research paper (scientific journal)  

Background: A growing body of evidence has shown that non-alcoholic fatty liver disease (NAFLD) is associated with chronic kidney disease (CKD). Non-invasive fibrosis assessments of NAFLD such as Fibrosis-4 (FIB-4) index and NAFLD fibrosis score (NFS) have been developed to substitute liver biopsy. Little is known about the association between FIB-4 index or NFS and the components of CKD.

Methods: In the present cross-sectional study, we assessed of 3640 Japanese CKD patients. We examined the association between FIB-4index or NFS and the odds of having low estimated glomerular filtration rate (eGFR) defined as eGFR < 60 mL/min/1.73 m2 or albuminuria defined as urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g. Patients were divided into quartiles according to their baseline FIB-4 index and NFS levels. Linear and logistic regression analysis were conducted, with adjustment for potential confounding factors.

Results: FIB-4 index and NFS were negatively associated with eGFR, but not UACR, after adjustment for potential confounding factors. Both FIB-4 index and NFS were significantly associated with low eGFR after adjustment for potential confounding factors. Meanwhile, in the multivariable-adjusted model, no associations were found between FIB-4 index or NFS and albuminuria. The addition of FIB-4 index or NFS to the established clinical CKD risk factors improved diagnostic accuracy of prevalence of low eGFR. We also found that there was a significant trend of higher FIB-4 index and NFS with more advanced renal fibrosis using the kidney biopsy data.

Conclusions: Higher non-invasive fibrosis assessments of NAFLD were associated with higher odds of decreased eGFR.

DOI： 10.1007/s10157-020-02018-z

Language：English   Publishing type：Research paper (scientific journal)  

Background With recent advances in endoscopic modalities, small bowel vascular lesions (SBVLs) are often now detected in patients with gastrointestinal bleeding. Given the high invasiveness of endoscopic treatment, it is important to select patients at high risk for bleeding.

Aim To assess the risk of rebleeding in patients with SBVLs as a systemic disease rather than a gastrointestinal disease in relation to their general health.

Methods We retrospectively analyzed the clinical data of 55 patients with SBVLs among patients with obscure gastrointestinal bleeding. The possible association between the clinical findings and the updated Charlson comorbidity index with rebleeding was evaluated.

Results Gastrointestinal rebleeding occurred in 20 patients (36.4%) during the follow-up period. The presence of multiple comorbidities as indicated by an updated Charlson comorbidity index of ≥4 was a risk factor for rebleeding (hazard ratio, 3.64; P = 0.004). Other risk factors were arteriosclerosis of the superior mesenteric artery and multiple SBVLs. Endoscopic hemostasis and the discontinuation of antithrombotic medications were not significantly associated with rebleeding. Patients with a high updated Charlson comorbidity index had a high risk of death of causes other than gastrointestinal rebleeding.

Conclusions Gastrointestinal rebleeding is not a rare condition among patients with SBVLs. Patients with poor general health may therefore have a higher risk of rebleeding.

DOI： 10.2169/internalmedicine.6341-20

Language：English   Publishing type：Research paper (scientific journal)  

Introduction: Angiotensin receptor blockers (ARBs) are preferably used in hypertensive patients with CKD. Azilsartan is a strong antihypertensive ARB, but its antiproteinuric effects are not well understood. We compared the antiproteinuric effect of azilsartan and candesartan in CKD patients in an open-label, randomized, crossover trial. Methods: A total of 111 patients were treated with 20 mg of azilsartan daily for 2 months as a run-in period. After the run-in period, patients were randomized into 2 arms and received either 20 mg of azilsartan or 8 mg of candesartan daily for 3 months in a crossover trial. The primary outcome was the percent change in urinary protein-to-Cr ratio (UPCR). Results: Ninety-five patients completed the trial. The mean age was 64.3 years. The estimated glomerular filtration rate (eGFR) and UPCR were 41.5 mL/min/1.73 m2 and 1.8 g/gCr, respectively. The baseline systolic and diastolic blood pressures were 131.4 and 71.0 mm Hg, respectively. The mean percent change in the UPCR was −3.8% in the azilsartan group and 30.8% in the candesartan group at the 1st endpoint (p = 0.0004), and 6.1% in the azilsartan group and 25.8% in the candesartan group at the 2nd (final) endpoint (p = 0.029). The incidence of adverse events, including eGFR levels and serum potassium levels, was not significantly different between the groups. Conclusion: A 20 mg azilsartan dose had potent antiproteinuric effects compared with an 8 mg candesartan dose, without an increase in adverse events. Azilsartan may provide renal protection in addition to antihypertensive effects in CKD patients.

DOI： 10.1159/000512365

Language：English  

DOI： 10.1002/hon.2816

Language：English   Publishing type：Research paper (scientific journal)  

Women have a longer life expectancy than men in the general population. However, it has remained unclear whether this advantage is maintained in patients undergoing maintenance hemodialysis. The aim of this study was to compare the risk of mortality, especially infection-related mortality, between male and female hemodialysis patients. A total of 3065 Japanese hemodialysis patients aged ≥ 18 years old were followed up for 10 years. The primary outcomes were all-cause and infection-related mortality. The associations between sex and these outcomes were examined using Cox proportional hazards models. During the median follow-up of 8.8 years, 1498 patients died of any cause, 387 of whom died of infection. Compared with men, the multivariable-adjusted hazard ratios (95% confidence interval) for all-cause and infection-related mortality in women were 0.51 (0.45-0.58, P < 0.05) and 0.36 (0.27-0.47, P < 0.05), respectively. These findings remained significant even when propensity score-matching or inverse probability of treatment weighting adjustment methods were employed. Furthermore, even when the non-infection-related mortality was considered a competing risk, the infection-related mortality rate in women was still significantly lower than that in men. Regarding all-cause and infection-related deaths, women have a survival advantage compared with men among Japanese patients undergoing maintenance hemodialysis.

DOI： 10.1038/s41598-021-03551-x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/hon.2816

Language：English   Publishing type：Research paper (scientific journal)  

The accumulation of glucose degradation products (GDPs) can lead to tissue damage in patients with diabetes and those undergoing long-term peritoneal dialysis (PD). Angiogenesis is occasionally observed in the peritoneal membrane of patients undergoing PD, where it is associated with failure of ultrafiltration. To investigate the mechanism underlying the influence of angiogenesis on fluid absorption, we evaluated the effects of accumulation of the glucose degradation product methylglyoxal (MGO) on angiogenesis in vitro, and analyzed the association with angiogenesis in the peritoneal membrane. To this end, we measured the levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in cultured endothelial and smooth muscle cells after administration of MGO. The expression of PDGF-BB mRNA and protein decreased significantly after exposure to MGO, while the expression of VEGF mRNA increased (both P < 0.01). The expression of PDGF-Rβ mRNA in cultured smooth muscle cells did not change after administration of MGO, although the expression of VEGF mRNA increased (P < 0.01). We also evaluated the associations between the number of capillary vessels, peritoneal function, and the degree of MGO deposition using peritoneum samples collected from patients undergoing PD. The number of immature capillary vessels was significantly associated with peritoneal dysfunction and the degree of MGO accumulation (both P < 0.01). In conclusion, MGO enhances the production of VEGF and suppresses the production of PDGF-BB, potentially leading to disturbance of angiogenesis in the peritoneal membrane. Accumulation of MGO in the peritoneum may cause immature angiogenesis and peritoneal dysfunction.

DOI： 10.1016/j.bbrc.2020.02.048

Language：English   Publishing type：Research paper (scientific journal)  

The accumulation of glucose degradation products (GDPs) can lead to tissue damage in patients with diabetes and those undergoing long-term peritoneal dialysis (PD). Angiogenesis is occasionally observed in the peritoneal membrane of patients undergoing PD, where it is associated with failure of ultrafiltration. To investigate the mechanism underlying the influence of angiogenesis on fluid absorption, we evaluated the effects of accumulation of the glucose degradation product methylglyoxal (MGO) on angiogenesis in vitro, and analyzed the association with angiogenesis in the peritoneal membrane. To this end, we measured the levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in cultured endothelial and smooth muscle cells after administration of MGO. The expression of PDGF-BB mRNA and protein decreased significantly after exposure to MGO, while the expression of VEGF mRNA increased (both P < 0.01). The expression of PDGF-Rβ mRNA in cultured smooth muscle cells did not change after administration of MGO, although the expression of VEGF mRNA increased (P < 0.01). We also evaluated the associations between the number of capillary vessels, peritoneal function, and the degree of MGO deposition using peritoneum samples collected from patients undergoing PD. The number of immature capillary vessels was significantly associated with peritoneal dysfunction and the degree of MGO accumulation (both P < 0.01). In conclusion, MGO enhances the production of VEGF and suppresses the production of PDGF-BB, potentially leading to disturbance of angiogenesis in the peritoneal membrane. Accumulation of MGO in the peritoneum may cause immature angiogenesis and peritoneal dysfunction.

DOI： 10.1016/j.bbrc.2020.02.048

Language：English   Publishing type：Research paper (scientific journal)  

Objective Uremic toxins are known risk factors for cancer in patients undergoing hemodialysis (HD). Although adequate removal of uremic toxins might reduce the cancer risk by improving subclinical uremia, the relationship between the dialysis dose and risk of cancer death in patients undergoing HD remains unclear. Methods In this prospective observational study, 3,450 patients undergoing HD were followed up for 4 years. The primary outcome was cancer death. Patients were divided into quartiles according to their baseline Kt/V levels. The association between the Kt/V levels and risk of cancer death was estimated using the Kaplan-Meier method and Cox proportional-hazards model. Results A total of 111 patients (3.2&#37;) died from cancer during the 4-year observational period. The 4-year survival rate decreased linearly with decreasing Kt/V. The multivariable-adjusted hazard ratios (HRs) and 95&#37; confidence intervals (CIs) for cancer death were 2.23 (95&#37; CI, 1.13-4.56), 1.77 (0.88-3.63), and 1.89 (1.04-3.56) in quartile (Q) 1, Q2, and Q3, respectively, compared with patients in the highest Kt/V category (Q4) (p for trend = 0.06). Every 0.1 increase in Kt/V was associated with a reduction of 8&#37; in cancer death (HR 0.92, 95&#37; CI, 0.85-0.99). Conclusion A lower dialysis dose might be associated with a higher risk of cancer death in patients undergoing HD. Kt/V is a simple indicator of dialysis dose used in clinical practice and might be a useful modifiable factor for predicting the risk of cancer death. Further basic and interventional studies are needed to confirm the apparent reduction in cancer death associated with increasing the dialysis dose.

DOI： 10.2169/internalmedicine.4027-19

Language：English   Publishing type：Research paper (scientific journal)  

Bilirubin is recognized as an endogenous antioxidant, and low serum bilirubin is reported to be associated with the progression of kidney disease. However, it is unclear whether serum bilirubin levels are associated with the loss of residual kidney function (RKF) in peritoneal dialysis (PD) patients. This study investigated the relationship between serum total bilirubin and loss of RKF. We prospectively followed 94 PD patients who started PD in our hospital between June 2006 and May 2016. Ten patients who had chronic liver disease or cirrhosis were excluded. Patients were divided into three groups based on serum total bilirubin concentration tertiles: tertile 1 (T1) < 0.3, T2 = 0.3, and T3 ≥ 0.4 mg/dL. We estimated the relationship between serum bilirubin and loss of RKF, defined as daily urine volume (<100 mL) within 3 years after starting PD, using a Cox proportional hazards model. During the 3-year observation period, 22 patients lost RKF. The incidence rate of loss of RKF increased linearly with the decrease in serum total bilirubin levels (P for trend < 0.05). After adjusting for confounding factors, low serum total bilirubin level was shown to be an independent predictor of loss of RKF (hazard ratio [HR] for every 0.1 mg/dL decrease, 1.50; 95&#37; confidence interval [CI], 1.01-2.51; HR [95&#37;CI] for T2 and T1 [vs. T3] 2.03 [0.65-7.88] and 3.70 [1.00-15.9]). This study suggests that low serum total bilirubin levels are associated with the loss of RKF in PD patients.

DOI： 10.1111/1744-9987.12865

Language：English   Publishing type：Research paper (scientific journal)  

Bilirubin is recognized as an endogenous antioxidant, and low serum bilirubin is reported to be associated with the progression of kidney disease. However, it is unclear whether serum bilirubin levels are associated with the loss of residual kidney function (RKF) in peritoneal dialysis (PD) patients. This study investigated the relationship between serum total bilirubin and loss of RKF. We prospectively followed 94 PD patients who started PD in our hospital between June 2006 and May 2016. Ten patients who had chronic liver disease or cirrhosis were excluded. Patients were divided into three groups based on serum total bilirubin concentration tertiles: tertile 1 (T1) < 0.3, T2 = 0.3, and T3 ≥ 0.4 mg/dL. We estimated the relationship between serum bilirubin and loss of RKF, defined as daily urine volume (<100 mL) within 3 years after starting PD, using a Cox proportional hazards model. During the 3-year observation period, 22 patients lost RKF. The incidence rate of loss of RKF increased linearly with the decrease in serum total bilirubin levels (P for trend < 0.05). After adjusting for confounding factors, low serum total bilirubin level was shown to be an independent predictor of loss of RKF (hazard ratio [HR] for every 0.1 mg/dL decrease, 1.50; 95% confidence interval [CI], 1.01–2.51; HR [95%CI] for T2 and T1 [vs. T3] 2.03 [0.65–7.88] and 3.70 [1.00–15.9]). This study suggests that low serum total bilirubin levels are associated with the loss of RKF in PD patients.

DOI： 10.1111/1744-9987.12865

Language：English   Publishing type：Research paper (scientific journal)  

Hypocomplementemic urticarial vasculitis syndrome (HUVS) is a small vessel vasculitis characterized by hypocomplementemia and urticaria-like exanthema. Some cases also display abdominal pain and membranoproliferative glomerulonephritis (MPGN) with immune complex deposits. We treated a case of HUVS with biopsy-proven gastrointestinal vasculitis and atypical histological findings in a kidney biopsy. The 36-year-old Japanese man, who was previously diagnosed with diffuse panbronchiolitis, visited our hospital due to transient urticaria-like exanthema and rapid deterioration of kidney function. On admission, the skin lesion was found to be only pigmentation, showing no vasculitis by skin biopsy. In laboratory findings, renal dysfunction with hematuria and proteinuria and hypocomplementemia were observed. Gastrointestinal vasculitis was proven by endoscopy and biopsy of the mucosa. Kidney biopsy revealed MPGN with crescents. No immune complex deposits were observed by immunofluorescence or electron microscopy. Additional examination revealed high titers of anti-C1q antibody. The patient was diagnosed with HUVS and treated with corticosteroids and plasma exchange. Although renal function and gastrointestinal vasculitis partially improved, infectious pneumonia frequently recurred. His renal dysfunction began to progress again and reached end-stage kidney disease. This is the first case of HUVS with biopsy-proven gastrointestinal vasculitis and MPGN without immune complex deposits. Notably, in some case of HUVS, anti-C1q antibody may activate the alternative complement pathway without immune complex deposits, resulting in renal injury.

DOI： 10.1007/s13730-019-00421-4

Language：English   Publishing type：Research paper (scientific journal)  

A 57-year-old woman with pre-dialysis chronic kidney disease (CKD) was hospitalized because of fever and fatigue. On admission, increased inflammatory response and pyuria with bacteriuria were observed. Pyelonephritis was successfully treated with antibiotics, whereas her fatigue continued and she developed progressive hypercalcemia and hyponatremia; serum sodium level, 116 mEq/L and corrected serum calcium level, 13.4 mg/dL. Plasma concentrations of adrenocorticotropic hormone and cortisol and serum luteinizing hormone were under the detection level. Although the reaction of other anterior pituitary hormones and the serum antidiuretic hormone (ADH) was preserved, the response of serum luteinizing hormone to administration of luteinizing hormone releasing hormone was impaired. Magnetic resonance imaging showed no structural abnormality in the thalamus, hypothalamus, and pituitary gland. She was diagnosed with adrenal insufficiency caused by partial hypopituitarism in concomitant with pyelonephritis. After starting hydrocortisone replacement, serum levels of sodium and calcium were rapidly normalized. This case highlights the importance of adrenal insufficiency as a differential diagnosis of hypercalcemia in patients with pre-dialysis CKD, especially when hyponatremia was concomitantly observed. Besides, infection should be considered as an important trigger for the development of latent adrenal insufficiency since it could increase the physiological demand of corticosteroid in the body. Also, CKD may enhance the magnitude of hypercalcemia since CKD patients have decreased capacity to increase urinary calcium excretion.

DOI： 10.1007/s13730-018-0371-9

Language：English   Publishing type：Research paper (scientific journal)  

Background Assessment of infection-related mortality remains inadequate in patients undergoing peritoneal dialysis. This study was performed to develop a risk model for predicting the 2-year infection-related mortality risk in patients undergoing peritoneal dialysis. Methods The study cohort comprised 606 patients who started and continued peritoneal dialysis for 90 at least days and was drawn from the Fukuoka Peritoneal Dialysis Database Registry Study in Japan. The patients were registered from 1 January 2006 to 31 December 2016 and followed up until 31 December 2017. To generate a prediction rule, the score for each variable was weighted by the regression coefficients calculated using a Cox proportional hazard model adjusted by risk factors for infection-related mortality, including patient characteristics, comorbidities, and laboratory data. Results During the follow-up period (median, 2.2 years), 138 patients died; 58 of them of infectious disease. The final model for infection-related mortality comprises six factors: age, sex, serum albumin, serum creatinine, total cholesterol, and weekly renal Kt/V. The incidence of infection-related mortality increased linearly with increasing total risk score (P for trend <0.001). Furthermore, the prediction model showed adequate discrimination (c-statistic = 0.79 [0.72–0.86]) and calibration (Hosmer–Lemeshow test, P = 0.47). Conclusion In this study, we developed a new model using clinical measures for predicting infection-related mortality in patients undergoing peritoneal dialysis.

DOI： 10.1371/journal.pone.0213922

Language：English   Publishing type：Research paper (scientific journal)  

Patients with anti-glomerular basement membrane (GBM) antibody glomerulonephritis typically exhibit rapidly progressive glomerulonephritis (RPGN). The renal outcome as well as the prognosis of this disease is worse than other forms of RPGN such as those from microscopic polyangiitis. Therefore, early therapeutic intervention is essential to improve its prognosis. One month before referral to our hospital, a 54-year-old female attended another hospital because of macrohematuria. At that time, she had proteinuria and macrohematuria with normal renal function, was negative for anti-GBM antibodies, and was diagnosed with chronic glomerulonephritis. A month later when she was admitted to our hospital, she showed renal insufficiency and was positive for anti-GBM antibodies. Immediately after recognizing the anti-GBM antibody status, plasma exchange and the first course of steroid pulse therapy was started. After 5 days of therapy, renal biopsy confirmed severe crescentic glomerulonephritis in which all the observed glomeruli were involved with cellular crescents. Despite this, she survived without end-stage renal disease after three courses of steroid pulse therapy and seven sessions of plasma exchange. This favorable outcome reflects the repeated analysis of anti-GBM antibodies within a very short period and the rapid therapeutic intervention in addition to the intensive immunosuppressive therapies.

DOI： 10.1159/000499401

Language：English   Publishing type：Research paper (scientific journal)  

The influence of pre-dialysis blood pressure (BP) on the prognosis of hemodialysis (HD) patients is still inconclusive.A total of 3436 HD patients were prospectively followed up for 4 years. The patients were divided into quintiles of pre-dialysis systolic BP (SBP) and diastolic BP (DBP) levels [mm Hg]: Quintile 1 (Q1), SBP <134, DBP <66; Q2, SBP 134 to 147, DBP 66 to 72; Q3, SBP 148 to 158, DBP 73 to 79; Q4, SBP 159 to 171, DBP 80 to 85; Q5, SBP ≥172, DBP ≥86. The association between the pre-dialysis BP and outcomes were examined using a Cox proportional hazards model.During a 4-year follow-up period, 564 (16.4&#37;) patients died of any cause and 590 (17.2&#37;) developed cardiovascular (CV) events. The lowest level of pre-dialysis SBP group (Q1) showed a significantly increased risk of all-cause mortality (hazard ratio [HR] 1.83, 95&#37; confidence interval [CI] 1.40-2.39) and the highest group (Q5) significantly increased risk of CV events (HR 1.31, 95&#37; CI 1.02-1.68) compared with the reference group (Q3), respectively. The highest level of pre-dialysis DBP group was significantly associated with increased risk for both all-cause mortality and CV events. Restricted cubic spline analysis for BP and outcomes suggested the optimal pre-dialysis BP value associated with the lowest risk of outcomes was SBP 152 mm Hg for all-cause mortality, SBP 143 mm Hg for CV events, and DBP 68 mm Hg for all-cause mortality.Our results suggested that pre-dialysis BP was independently associated with all-cause mortality and CV events among Japanese HD patients.

DOI： 10.1097/MD.0000000000013485

Language：English   Publishing type：Research paper (scientific journal)  

The influence of pre-dialysis blood pressure (BP) on the prognosis of hemodialysis (HD) patients is still inconclusive. A total of 3436 HD patients were prospectively followed up for 4 years. The patients were divided into quintiles of pre-dialysis systolic BP (SBP) and diastolic BP (DBP) levels [mm Hg]: Quintile 1 (Q1), SBP <134, DBP <66; Q2, SBP 134 to 147, DBP 66 to 72; Q3, SBP 148 to 158, DBP 73 to 79; Q4, SBP 159 to 171, DBP 80 to 85; Q5, SBP ≥172, DBP ≥86. The association between the pre-dialysis BP and outcomes were examined using a Cox proportional hazards model. During a 4-year follow-up period, 564 (16.4%) patients died of any cause and 590 (17.2%) developed cardiovascular (CV) events. The lowest level of pre-dialysis SBP group (Q1) showed a significantly increased risk of all-cause mortality (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.40–2.39) and the highest group (Q5) significantly increased risk of CV events (HR 1.31, 95% CI 1.02–1.68) compared with the reference group (Q3), respectively. The highest level of pre-dialysis DBP group was significantly associated with increased risk for both all-cause mortality and CV events. Restricted cubic spline analysis for BP and outcomes suggested the optimal pre-dialysis BP value associated with the lowest risk of outcomes was SBP 152 mm Hg for all-cause mortality, SBP 143 mm Hg for CV events, and DBP 68 mm Hg for all-cause mortality. Our results suggested that pre-dialysis BP was independently associated with all-cause mortality and CV events among Japanese HD patients.

DOI： 10.1097/MD.0000000000013485

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: The contribution of the hemoglobin concentration to the incidence of hemorrhagic or ischemic stroke in patients undergoing hemodialysis is unclear. METHODS: In total, 3436 patients undergoing prevalent hemodialysis were followed up for 4 years. The primary outcome was the first development of hemorrhagic or ischemic stroke. The baseline hemoglobin concentration was divided into quartiles [hemoglobin (g/dL): Q1, ≤9.7; Q2, 9.8-10.5; Q3, 10.6-11.1; Q4, ≥11.2]. The association between the hemoglobin concentration and each type of stroke was examined using the Kaplan-Meier method and a Cox proportional hazards model. RESULTS: During the follow-up period, 76 (2.2&#37;) patients developed hemorrhagic stroke and 139 (4.0&#37;) developed ischemic stroke. The 4-year incidence rate of hemorrhagic stroke was significantly higher in patients with lower hemoglobin concentrations. Compared with the quartile of patients with the highest hemoglobin concentrations (Q4), the multivariable-adjusted hazard ratios for hemorrhagic stroke were 1.18 (95&#37; confidence interval, 0.56-2.51), 1.59 (0.82-3.21) and 2.31 (1.16-4.73) in patients in Q3, Q2 and Q1, respectively. No association was identified between the 4-year incidence rate of ischemic stroke and the hemoglobin concentration. Compared with the quartile of patients with the lowest hemoglobin concentrations (Q1), the multivariable-adjusted hazard ratios for ischemic stroke were 1.17 (95&#37; confidence interval, 0.73-1.89), 0.88 (0.51-1.51) and 1.10 (0.66-1.83) in patients in Q2, Q3 and Q4, respectively. CONCLUSIONS: Our results suggest that low hemoglobin concentrations are associated with a high risk of hemorrhagic stroke, but not of ischemic stroke, in patients undergoing hemodialysis.

DOI： 10.1093/ndt/gfx305

Language：English   Publishing type：Research paper (scientific journal)  

Background. The contribution of the hemoglobin concentration to the incidence of hemorrhagic or ischemic stroke in patients undergoing hemodialysis is unclear. Methods. In total, 3436 patients undergoing prevalent hemodialysis were followed up for 4 years. The primary outcome was the first development of hemorrhagic or ischemic stroke. The baseline hemoglobin concentration was divided into quartiles [hemoglobin (g/dL): Q1,9.7; Q2, 9.8-10.5; Q3, 10.6-11.1; Q4,11.2]. The association between the hemoglobin concentration and each type of stroke was examined using the Kaplan- Meiermethod and a Cox proportional hazardsmodel. Results. During the follow-up period, 76 (2.2%) patients developed hemorrhagic stroke and 139 (4.0%) developed ischemic stroke. The 4-year incidence rate of hemorrhagic stroke was significantly higher in patients with lower hemoglobin concentrations. Compared with the quartile of patients with the highest hemoglobin concentrations (Q4), the multivariable-adjusted hazard ratios for hemorrhagic stroke were 1.18 (95% confidence interval, 0.56-2.51), 1.59 (0.82-3.21) and 2.31 (1.16-4.73) in patients in Q3, Q2 and Q1, respectively. No association was identified between the 4-year incidence rate of ischemic stroke and the hemoglobin concentration. Compared with the quartile of patients with the lowest hemoglobin concentrations (Q1), the multivariable-adjusted hazard ratios for ischemic stroke were 1.17 (95% confidence interval, 0.73-1.89), 0.88 (0.51-1.51) and 1.10 (0.66-1.83) in patients in Q2, Q3 and Q4, respectively. Conclusions. Our results suggest that low hemoglobin concentrations are associated with a high risk of hemorrhagic stroke, but not of ischemic stroke, in patients undergoing hemodialysis.

DOI： 10.1093/ndt/gfx305

Language：English   Publishing type：Research paper (scientific journal)  

Serum albumin is the major intravascular antioxidant. Though oxidative stress plays an important role in the pathophysiology of Immunoglobulin A nephropathy (IgAN), the association between serum albumin and the progression of IgAN is not entirely understood. This retrospective cohort study of 1,352 participants with biopsy-proven IgAN determined the associations between serum albumin level and the incidence of end-stage renal disease (ESRD) using a Cox proportional hazards model. Patients were divided into three groups by tertiles of serum albumin level: Low, Middle, and High group (3.9 g/dL, 4.0–4.3 g/dL, 4.4 g/dL, respectively). During the median 5.1-year follow-up period, 152 patients (11.2%) developed ESRD. Participants in the Low group had a 1.88-fold increased risk for ESRD compared with those in the High group after adjustment for clinical parameters, including urinary protein excretion, and pathological parameters (Oxford classification). We also experimentally proved the antioxidant capacity of albumin on mesangial cells. The intracellular reactive oxygen species and mitochondrial injury, induced by hydrogen peroxide were significantly attenuated in albumin-pretreated mouse mesangial cells and human kidney cells compared with γ-globulin-pretreated cells. Low serum albumin level is an independent risk factor for ESRD in patients with IgAN. The mechanism could be explained by the antioxidant capacity of serum albumin.

DOI： 10.1371/journal.pone.0196655

Language：English   Publishing type：Research paper (scientific journal)  

Renal fibrosis is the final common pathway of chronic kidney diseases. Lymphatic vessel (LV) proliferation is found in human renal diseases and other fibrotic diseases, suggesting that lymphangiogenesis is associated with the progression or suppression of kidney diseases. However, the purpose of LV proliferation is not completely understood. We investigated the effect of vascular endothelial growth factor (VEGF)-C on lymphangiogenesis, inflammation, and fibrosis in the mouse kidney using the unilateral ureteral obstruction (UUO) model. In UUO mice, significant proliferation of LVs was accompanied by tubulointerstitial nephritis and fibrosis. We continuously administered recombinant human VEGF-C to UUO model mice using an osmotic pump (UUO+VEGF-C group). Lymphangiogenesis was significantly induced in the UUO+VEGF-C group compared with the vehicle group, despite similar numbers of capillaries in both groups. The number of infiltrating macrophages, and levels of inflammatory cytokines and transforming growth factor-β1 were reduced in the UUO+VEGF-C group compared with the vehicle group. Renal fibrosis was consequently attenuated in the UUO+VEGF-C group. In cultured lymphatic endothelial cells, administration of VEGF-C increased the activity and proliferation of lymphatic endothelial cells (LECs) and expression of adhesion molecules such as vascular cell adhesion molecule-1. These findings suggest that induction of lymphangiogenesis ameliorates inflammation and fibrosis in the renal interstitium. Enhancement of the VEGF-C signaling pathway in LECs may be a therapeutic strategy for renal fibrosis.

DOI： 10.1038/labinvest.2017.77

Language：English   Publishing type：Research paper (scientific journal)  

Renal fibrosis is the final common pathway of chronic kidney diseases. Lymphatic vessel (LV) proliferation is found in human renal diseases and other fibrotic diseases, suggesting that lymphangiogenesis is associated with the progression or suppression of kidney diseases. However, the purpose of LV proliferation is not completely understood. We investigated the effect of vascular endothelial growth factor (VEGF)-C on lymphangiogenesis, inflammation, and fibrosis in the mouse kidney using the unilateral ureteral obstruction (UUO) model. In UUO mice, significant proliferation of LVs was accompanied by tubulointerstitial nephritis and fibrosis. We continuously administered recombinant human VEGF-C to UUO model mice using an osmotic pump (UUO+VEGF-C group). Lymphangiogenesis was significantly induced in the UUO+VEGF-C group compared with the vehicle group, despite similar numbers of capillaries in both groups. The number of infiltrating macrophages, and levels of inflammatory cytokines and transforming growth factor-β1 were reduced in the UUO+VEGF-C group compared with the vehicle group. Renal fibrosis was consequently attenuated in the UUO+VEGF-C group. In cultured lymphatic endothelial cells, administration of VEGF-C increased the activity and proliferation of lymphatic endothelial cells (LECs) and expression of adhesion molecules such as vascular cell adhesion molecule-1. These findings suggest that induction of lymphangiogenesis ameliorates inflammation and fibrosis in the renal interstitium. Enhancement of the VEGF-C signaling pathway in LECs may be a therapeutic strategy for renal fibrosis.

DOI： 10.1038/labinvest.2017.77

Language：English   Publishing type：Research paper (scientific journal)  

Adhesion of cells to the extracellular matrix (ECM) via focal adhesions (FAs) is crucial for cell survival, migration, and differentiation. Although the regulation of FAs, including by integrins and the ECM, is important to cell behavior, how FAs are regulated is not well known. Autophagy is induced by both cell adhesion and cell detachment. Here, we showed that autophagosomes are located close to internalized collagen and paxillin, which is a well-known marker of FAs. Autophagy-deficient cells showed increased levels of internalized collagen compared with control cells. Moreover, paxillin exhibited a more peripheral distribution and the area of paxillin was increased, and adhesion-induced focal adhesion kinase signaling was impaired and adhesion was enhanced, in autophagy-deficient cells. These results suggest that autophagy suppressed cell adhesion by regulating internalized ECM and FAs.

DOI： 10.1242/bio.027458

Language：English   Publishing type：Research paper (scientific journal)  

Adhesion of cells to the extracellular matrix (ECM) via focal adhesions (FAs) is crucial for cell survival, migration, and differentiation. Although the regulation of FAs, including by integrins and the ECM, is important to cell behavior, how FAs are regulated is not well known. Autophagy is induced by both cell adhesion and cell detachment. Here, we showed that autophagosomes are located close to internalized collagen and paxillin, which is a well-known marker of FAs. Autophagy-deficient cells showed increased levels of internalized collagen compared with control cells. Moreover, paxillin exhibited a more peripheral distribution and the area of paxillin was increased, and adhesion-induced focal adhesion kinase signaling was impaired and adhesion was enhanced, in autophagy-deficient cells. These results suggest that autophagy suppressed cell adhesion by regulating internalized ECM and FAs.

DOI： 10.1242/bio.027458

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Cardiothoracic ratio by chest radiography is commonly used to assess volume status. Little is known about the relationships between cardiothoracic ratio and the incidence of clinical outcomes in patients undergoing hemodialysis (HD). STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 3,436 participants in the Q-Cohort Study 18 years or older who underwent maintenance HD in Japan. PREDICTOR: Cardiothoracic ratio. OUTCOMES & MEASUREMENTS: All-cause mortality and cardiovascular disease (CVD) events. RESULTS: During a 4-year follow-up period, 564 (16.4&#37;) patients died of any cause and 590 (17.2&#37;) developed CVD events. From baseline cardiothoracic ratios, participants were categorized into sex-specific quartiles because cardiothoracic ratio distribution differed by sex. The 4-year event-free survival rate, in terms of all-cause mortality and CVD events, was significantly lower with higher cardiothoracic ratios. Compared to the lowest cardiothoracic ratio (quartile 1), multivariable-adjusted HRs for all-cause mortality were 0.89 (95&#37; CI, 0.66-1.20), 1.41 (1.08-1.86), and 1.52 (1.17-2.00) in patients from quartiles 2, 3, and 4, respectively. Similarly, in comparison to quartile 1, multivariable-adjusted HRs for CVD events were 1.00 (95&#37; CI, 0.77-1.31), 1.18 (0.92-1.53), and 1.37 (1.07-1.76) in patients from quartiles 2, 3, and 4, respectively. Furthermore, the combination of higher cardiothoracic ratio and normohypotension (systolic blood pressure < 140mmHg and diastolic blood pressure < 90mmHg) was associated with higher risk for CVD events. LIMITATIONS: Single measurement of all variables, potentially less-heterogeneous patient population, and limited ascertainment of cardiac parameters and the outcomes. CONCLUSIONS: Higher cardiothoracic ratio is associated with higher risk for both all-cause mortality and CVD events in patients undergoing HD.

DOI： 10.1053/j.ajkd.2016.11.026

Language：English   Publishing type：Research paper (scientific journal)  

Background Cardiothoracic ratio by chest radiography is commonly used to assess volume status. Little is known about the relationships between cardiothoracic ratio and the incidence of clinical outcomes in patients undergoing hemodialysis (HD). Study Design Prospective cohort study. Setting & Participants 3,436 participants in the Q-Cohort Study 18 years or older who underwent maintenance HD in Japan. Predictor Cardiothoracic ratio. Outcomes & Measurements All-cause mortality and cardiovascular disease (CVD) events. Results During a 4-year follow-up period, 564 (16.4%) patients died of any cause and 590 (17.2%) developed CVD events. From baseline cardiothoracic ratios, participants were categorized into sex-specific quartiles because cardiothoracic ratio distribution differed by sex. The 4-year event-free survival rate, in terms of all-cause mortality and CVD events, was significantly lower with higher cardiothoracic ratios. Compared to the lowest cardiothoracic ratio (quartile 1), multivariable-adjusted HRs for all-cause mortality were 0.89 (95% CI, 0.66-1.20), 1.41 (1.08-1.86), and 1.52 (1.17-2.00) in patients from quartiles 2, 3, and 4, respectively. Similarly, in comparison to quartile 1, multivariable-adjusted HRs for CVD events were 1.00 (95% CI, 0.77-1.31), 1.18 (0.92-1.53), and 1.37 (1.07-1.76) in patients from quartiles 2, 3, and 4, respectively. Furthermore, the combination of higher cardiothoracic ratio and normohypotension (systolic blood pressure < 140 mm Hg and diastolic blood pressure < 90 mm Hg) was associated with higher risk for CVD events. Limitations Single measurement of all variables, potentially less-heterogeneous patient population, and limited ascertainment of cardiac parameters and the outcomes. Conclusions Higher cardiothoracic ratio is associated with higher risk for both all-cause mortality and CVD events in patients undergoing HD.

DOI： 10.1053/j.ajkd.2016.11.026

Language：English   Publishing type：Research paper (scientific journal)  

Recently, low serum uric acid (SUA) levels and high SUA levels, have emerged as risk factors for cardiovascular disease, as well as for the incidence of acute kidney injury and chronic kidney disease (CKD). However, the effect of low SUA on the progression of CKD remains unclear. To evaluate the association between SUA and renal prognosis in patients with immunoglobulin A nephropathy (IgAN), one of the most common causes of CKD, we retrospectively followed 1218 patients who were diagnosed with primary IgAN by kidney biopsy between October 1979 and December 2010. Patients were divided into three groups on the basis of SUA level tertiles: low (L group), middle (M group) and high (H group) tertiles (<6.1, 6.1-7.0, and >7.0 mg dl-1, respectively, for men and <4.4, 4.4-5.3, and >5.3 mg dl-1, respectively, for women). The risk factors for developing end-stage renal disease (ESRD) were estimated using a Cox proportional hazards model. After a median follow-up of 5.1 years, 142 patients (11.7&#37;) developed ESRD. The hazard ratio (95&#37; confidence interval) showed a J-shaped trend with the tertiles in both men (1.18 (0.55-2.54), 1.00 (reference), and 1.80 (1.01-3.10) in L, M and H groups, respectively) and women (2.73 (1.10-6.76), 1.00 (reference) and 2.49 (1.16-5.34) in L, M and H groups, respectively). Notably, low SUA was significantly associated with incident ESRD in women. This finding suggests that SUA has a J-shaped association with ESRD in patients with IgAN, especially women.

DOI： 10.1038/hr.2016.134

Language：English   Publishing type：Research paper (scientific journal)  

Recently, low serum uric acid (SUA) levels and high SUA levels, have emerged as risk factors for cardiovascular disease, as well as for the incidence of acute kidney injury and chronic kidney disease (CKD). However, the effect of low SUA on the progression of CKD remains unclear. To evaluate the association between SUA and renal prognosis in patients with immunoglobulin A nephropathy (IgAN), one of the most common causes of CKD, we retrospectively followed 1218 patients who were diagnosed with primary IgAN by kidney biopsy between October 1979 and December 2010. Patients were divided into three groups on the basis of SUA level tertiles: Low (L group), middle (M group) and high (H group) tertiles (<6.1, 6.1-7.0, and >7.0 mg dl^-1, respectively, for men and <4.4, 4.4-5.3, and >5.3 mg dl^-1, respectively, for women). The risk factors for developing end-stage renal disease (ESRD) were estimated using a Cox proportional hazards model. After a median follow-up of 5.1 years, 142 patients (11.7%) developed ESRD. The hazard ratio (95% confidence interval) showed a J-shaped trend with the tertiles in both men (1.18 (0.55-2.54), 1.00 (reference), and 1.80 (1.01-3.10) in L, M and H groups, respectively) and women (2.73 (1.10-6.76), 1.00 (reference) and 2.49 (1.16-5.34) in L, M and H groups, respectively). Notably, low SUA was significantly associated with incident ESRD in women. This finding suggests that SUA has a J-shaped association with ESRD in patients with IgAN, especially women.

DOI： 10.1038/hr.2016.134

Language：English   Publishing type：Research paper (scientific journal)  

Alterations in the apoptosis of immune cells have been associated with autoimmunity. Here, we have identified a homozygous missense mutation in the gene encoding the base excision repair enzyme Nei endonuclease VIII-like 3 (NEIL3) that abolished enzymatic activity in 3 siblings from a consanguineous family. The NEIL3 mutation was associated with fatal recurrent infections, severe autoimmunity, hypogammaglobulinemia, and impaired B cell function in these individuals. The same homozygous NEIL3 mutation was also identified in an asymptomatic individual who exhibited elevated levels of serum autoantibodies and defective peripheral B cell tolerance, but normal B cell function. Further analysis of the patients revealed an absence of LPS-responsive beige-like anchor (LRBA) protein expression, a known cause of immunodeficiency. We next examined the contribution of NEIL3 to the maintenance of self-tolerance in Neil3-/- mice. Although Neil3-/- mice displayed normal B cell function, they exhibited elevated serum levels of autoantibodies and developed nephritis following treatment with poly(I:C) to mimic microbial stimulation. In Neil3-/- mice, splenic T and B cells as well as germinal center B cells from Peyer's patches showed marked increases in apoptosis and cell death, indicating the potential release of self-antigens that favor autoimmunity. These findings demonstrate that deficiency in NEIL3 is associated with increased lymphocyte apoptosis, autoantibodies, and predisposition to autoimmunity.

DOI： 10.1172/JCI85647

Language：English   Publishing type：Research paper (scientific journal)  

Extended catheters with an upper abdominal exit-site (UAE) are reportedly associated with a lower incidence of peritoneal dialysis (PD)-related infections. However, little information about the optimal peritoneal catheter configuration for UAE is available. In this nonrandomized multicenter trial, 147 consecutive cases of a UAE involving either a conventional straight (CS; 80 cases) or extended swan-neck catheter (SN; 67 cases) were analyzed to compare exit-site and tunnel infections (ESTI), peritonitis, and catheter survival. The ESTI-free and catheter survival rates were significantly lower in the SN than in the CS group (P <0.01). However, the peritonitis-free survival rate was not different (P = 0.26). In terms of analyses for infection rates, fewer episodes of ESTI (1.284 vs 0.608 episodes/patient-year; P <0.01) and peritonitis (0.345 vs 0.152 episodes/patient-year; P = 0.06) were observed in the SN than CS group. Recurrence analyses showed that the mean number of cumulative episodes of ESTI and peritonitis between two groups were significantly different.

DOI： 10.1111/1744-9987.12358

Language：English   Publishing type：Research paper (scientific journal)  

Extended catheters with an upper abdominal exit-site (UAE) are reportedly associated with a lower incidence of peritoneal dialysis (PD)-related infections. However, little information about the optimal peritoneal catheter configuration for UAE is available. In this nonrandomized multicenter trial, 147 consecutive cases of a UAE involving either a conventional straight (CS; 80 cases) or extended swan-neck catheter (SN; 67 cases) were analyzed to compare exit-site and tunnel infections (ESTI), peritonitis, and catheter survival. The ESTI-free and catheter survival rates were significantly lower in the SN than in the CS group (P <0.01). However, the peritonitis-free survival rate was not different (P=0.26). In terms of analyses for infection rates, fewer episodes of ESTI (1.284 vs 0.608 episodes/patient-year; P <0.01) and peritonitis (0.345 vs 0.152 episodes/patient-year; P=0.06) were observed in the SN than CS group. Recurrence analyses showed that the mean number of cumulative episodes of ESTI and peritonitis between two groups were significantly different.

DOI： 10.1111/1744-9987.12358

Language：English   Publishing type：Research paper (scientific journal)  

Urinary protein (UP) is widely used as a clinical marker for podocyte injury; however, not all proteinuric nephropathies fit this model. We previously described the elevation of urinary angiotensinogen (AGT) accompanied by AGT expression by injured podocytes in a nitric oxide inhibition rat model (Eriguchi M, Tsuruya K, Haruyama N, Yamada S, Tanaka S, Suehiro T, Noguchi H, Masutani K, Torisu K, Kitazono T. Kidney Int 87: 116-127, 2015). In this report, we performed the human and animal studies to examine the significance and origin of urinary AGT. In the human study, focal segmental glomerulosclerosis (FSGS) patients presented with higher levels of urinary AGT, corrected by UP, than minimal-change disease (MCD) patients. Furthermore, AGT was evident in podocin-negative glomerular segmental lesions. We also tested two different nephrotic models induced by puromycin aminonucleoside in Wistar rats. The urinary AGT/UP ratio and AGT protein and mRNA expression in sieved glomeruli from FSGS rats were significantly higher than in MCD rats. The presence of AGT at injured podocytes in FSGS rats was detected by immunohistochemistry and immunoelectron microscopy. Finally, we observed the renal tissue and urinary metabolism of exogenous injected human recombinant AGT (which is not cleaved by rodent renin) in FSGS and control rats. Significant amounts of human AGT were detected in the urine of FSGS rats, but not of control rats. Immunostaining for rat and human AGT identified that only rat AGT was detected in injured podocytes, and filtered human AGT was seen in superficial proximal tubules, but not in injured podocytes, suggesting AGT generation by injured podocytes. In conclusion, the urinary AGT/UP ratio represents a novel specific marker of podocyte injury.

DOI： 10.1152/ajprenal.00260.2015

Language：English   Publishing type：Research paper (scientific journal)  

Urinary protein (UP) is widely used as a clinical marker for podocyte injury; however, not all proteinuric nephropathies fit this model. We previously described the elevation of urinary angiotensinogen (AGT) accompanied by AGT expression by injured podocytes in a nitric oxide inhibition rat model (Eriguchi M, Tsuruya K, Haruyama N, Yamada S, Tanaka S, Suehiro T, Noguchi H, Masutani K, Torisu K, Kitazono T. Kidney Int 87: 116–127, 2015). In this report, we performed the human and animal studies to examine the significance and origin of urinary AGT. In the human study, focal segmental glomerulosclerosis (FSGS) patients presented with higher levels of urinary AGT, corrected by UP, than minimal-change disease (MCD) patients. Furthermore, AGT was evident in podocin-negative glomerular segmental lesions. We also tested two different nephrotic models induced by puromycin aminonucleoside in Wistar rats. The urinary AGT/UP ratio and AGT protein and mRNA expression in sieved glomeruli from FSGS rats were significantly higher than in MCD rats. The presence of AGT at injured podocytes in FSGS rats was detected by immunohistochemistry and immunoelectron microscopy. Finally, we observed the renal tissue and urinary metabolism of exogenous injected human recombinant AGT (which is not cleaved by rodent renin) in FSGS and control rats. Significant amounts of human AGT were detected in the urine of FSGS rats, but not of control rats. Immunostaining for rat and human AGT identified that only rat AGT was detected in injured podocytes, and filtered human AGT was seen in superficial proximal tubules, but not in injured podocytes, suggesting AGT generation by injured podocytes. In conclusion, the urinary AGT/UP ratio represents a novel specific marker of podocyte injury.

DOI： 10.1152/ajprenal.00260.2015

Language：English   Publishing type：Research paper (scientific journal)  

The physiological role of autophagic flux within the vascular endothelial layer remains poorly understood. Here, we show that in primary endothelial cells, oxidized and native LDL stimulates autophagosome formation. Moreover, by both confocal and electron microscopy, excess native or modified LDL appears to be engulfed within autophagic structures. Transient knockdown of the essential autophagy gene ATG7 resulted in higher levels of intracellular ¹²⁵I-LDL and oxidized LDL (OxLDL) accumulation, suggesting that in endothelial cells, autophagy may represent an important mechanism to regulate excess, exogenous lipids. The physiological importance of these observations was assessed using mice containing a conditional deletion of ATG7 within the endothelium. Following acute intravenous infusion of fluorescently labeled OxLDL, mice lacking endothelial expression of ATG7 demonstrated prolonged retention of OxLDL within the retinal pigment epithelium (RPE) and choroidal endothelium of the eye. In a chronic model of lipid excess, we analyzed atherosclerotic burden in ApoE^-/-mice with or without endothelial autophagic flux. The absence of endothelial autophagy markedly increased atherosclerotic burden. Thus, in both an acute and chronic in vivo model, endothelial autophagy appears critically important in limiting lipid accumulation within the vessel wall. As such, strategies that stimulate autophagy, or prevent the age-dependent decline in autophagic flux, might be particularly beneficial in treating atherosclerotic vascular disease.

DOI： 10.1111/acel.12423

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Vascular calcification (VC) is a critical complication in patients with chronic kidney disease (CKD). The effects of spironolactone (SPL), a mineralocorticoid receptor (MR) antagonist, on VC have not been fully investigated in CKD. The present in vivo study determined the protective effects of SPL on VC in CKD rats. Rats were divided into a control group and four groups of rats with adenine-induced CKD. Three groups were treated with 0, 50, and 100 mg·kg(-1)·day(-1) SPL for 8 wk, and one group was treated with 100 mg·kg(-1)·day(-1) SPL for the last 2 wk of the 8-wk treatment period. After 8 wk, CKD rats developed azotemia and hyperphosphatemia, with increases in the expression of serum and glucocorticoid-regulated kinase-1 and sodium-phosphate cotransporter, in inflammation and oxidative stress level, in osteogenic signaling and apoptosis, and in aortic calcification, compared with control rats. SPL dose dependently decreased these changes in the aortas, concomitant with improvements in renal inflammation, tubulointerstitial nephritis, and kidney function. SPL neither lowered blood pressure level nor induced hyperkalemia. Treatment of CKD rats for the last 2 wk with 100 mg·kg(-1)·day(-1) SPL attenuated VC compared with CKD rats with the same degree of kidney function and hyperphosphatemia. In conclusion, SPL dose dependently inhibits the progression of VC by suppressing MR signaling, local inflammation, osteogenic transition, and apoptosis in the aortas of CKD rats.

DOI： 10.1152/ajprenal.00669.2014

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BACKGROUND: IgG4-related disease is a novel disease entity characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. Typical renal pathology is tubulointerstitial nephritis with storiform fibrosis, although the co-existence of various glomerular lesions has been described. Here, we present the first report of a case of IgG4-related kidney disease and membranoproliferative glomerulonephritis showing the discrepancy in IgG subclasses between the kidney interstitium and glomeruli. CASE PRESENTATION: A 70-year-old Japanese woman was diagnosed with membranoproliferative glomerulonephritis and focal tubulointerstitial nephritis with IgG4-positive plasma cells. Immunofluorescence studies revealed predominant deposition of IgG3 and IgG2, but not IgG4 in the glomeruli. We administered oral prednisolone at 30 mg/day, and the abnormalities in urine and blood tests gradually resolved. CONCLUSION: In this case, different patterns of IgG subclasses detected in the glomeruli and interstitial plasma cells suggest overlapping immunologic abnormalities. The favorable clinical course in our patient suggests that steroid therapy is promising in cases of IgG4-related kidney disease accompanied by glomerulonephritis.

DOI： 10.1186/s12882-015-0164-8

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Background: IgG4-related disease is a novel disease entity characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. Typical renal pathology is tubulointerstitial nephritis with storiform fibrosis, although the co-existence of various glomerular lesions has been described. Here, we present the first report of a case of IgG4-related kidney disease and membranoproliferative glomerulonephritis showing the discrepancy in IgG subclasses between the kidney interstitium and glomeruli. Case presentation: A 70-year-old Japanese woman was diagnosed with membranoproliferative glomerulonephritis and focal tubulointerstitial nephritis with IgG4-positive plasma cells. Immunofluorescence studies revealed predominant deposition of IgG3 and IgG2, but not IgG4 in the glomeruli. We administered oral prednisolone at 30 mg/day, and the abnormalities in urine and blood tests gradually resolved. Conclusion: In this case, different patterns of IgG subclasses detected in the glomeruli and interstitial plasma cells suggest overlapping immunologic abnormalities. The favorable clinical course in our patient suggests that steroid therapy is promising in cases of IgG4-related kidney disease accompanied by glomerulonephritis.

DOI： 10.1186/s12882-015-0164-8

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/dnares/dsv006

Language：English   Publishing type：Research paper (scientific journal)  

We elucidate the underlying mechanisms of bidirectional cardiorenal interaction, focusing on the sympathetic nerve driving disruption of the local renin-angiotensin system (RAS). A rat model of N(ω)-nitro-L-arginine methyl ester (L-NAME; a nitric oxide synthase inhibitor) administration was used to induce damage in the heart and kidney, similar to cardiorenal syndrome. L-NAME induced sympathetic nerve-RAS overactivity and cardiorenal injury accompanied by local RAS elevations. These were suppressed by bilateral renal denervation, but not by hydralazine treatment, despite the blood pressure being kept the same between the two groups. Although L-NAME induced angiotensinogen (AGT) protein augmentation in both organs, AGT mRNA decreased in the kidney and increased in the heart in a contradictory manner. Immunostaining for AGT suggested that renal denervation suppressed AGT onsite generation from activated resident macrophages of the heart and circulating AGT excretion from glomeruli of the kidney. We also examined rats treated with L-NAME plus unilateral denervation to confirm direct sympathetic regulation of intrarenal RAS. The levels of urinary AGT and renal angiotensin II content and the degrees of renal injury from denervated kidneys were less than those from contralateral innervated kidneys within the same rats. Thus, renal denervation has blood pressure-independent beneficial effects associated with local RAS inhibition.

DOI： 10.1038/ki.2014.220

Language：English   Publishing type：Research paper (scientific journal)  

Vascular calcification (VC) is a critical complication in patients with chronic kidney disease (CKD). The effects of spironolactone (SPL), a mineralocorticoid receptor (MR) antagonist, on VC have not been fully investigated in CKD. The present in vivo study determined the protective effects of SPL on VC in CKD rats. Rats were divided into a control group and four groups of rats with adenine-induced CKD. Three groups were treated with 0, 50, and 100 mg·kg^-1·day^-1 SPL for 8 wk, and one group was treated with 100 mg·kg^-1·day^-1 SPL for the last 2 wk of the 8-wk treatment period. After 8 wk, CKD rats developed azotemia and hyperphosphatemia, with increases in the expression of serum and glucocorticoid-regulated kinase-1 and sodium-phosphate cotransporter, in inflammation and oxidative stress level, in osteogenic signaling and apoptosis, and in aortic calcification, compared with control rats. SPL dose dependently decreased these changes in the aortas, concomitant with improvements in renal inflammation, tubulointerstitial nephritis, and kidney function. SPL neither lowered blood pressure level nor induced hyperkalemia. Treatment of CKD rats for the last 2 wk with 100 mg·kg^-1·day^-1 SPL attenuated VC compared with CKD rats with the same degree of kidney function and hyperphosphatemia. In conclusion, SPL dose dependently inhibits the progression of VC by suppressing MR signaling, local inflammation, osteogenic transition, and apoptosis in the aortas of CKD rats.

DOI： 10.1152/ajprenal.00669.2014

Language：English   Publishing type：Research paper (scientific journal)  

We elucidate The underlying mechanisms of bidirectional cardiorenal interaction, focusing on The sympathetic nerve driving disruption of The local renin-angiotensin system (RAS). A rat model of N ω-nitro-L-arginine methyl ester (L-NAME; a nitric oxide synthase inhibitor) administration was used to induce damage in The heart and kidney, similar to cardiorenal syndrome. L-NAME induced sympathetic nerve-RAS overactivity and cardiorenal injury accompanied by local RAS elevations. These were suppressed by bilateral renal denervation, but not by hydralazine treatment, despite The blood pressure being kept The same between The two groups. Although L-NAME induced angiotensinogen (AGT) protein augmentation in both organs, AGT mRNA decreased in The kidney and increased in The heart in a contradictory manner. Immunostaining for AGT suggested that renal denervation suppressed AGT onsite generation from activated resident macrophages of The heart and circulating AGT excretion from glomeruli of The kidney. We also examined rats treated with L-NAME plus unilateral denervation to confirm direct sympathetic regulation of intrarenal RAS. The levels of urinary AGT and renal angiotensin II content and The degrees of renal injury from denervated kidneys were less than those from contralateral innervated kidneys within The same rats. Thus, renal denervation has blood pressure-independent beneficial effects associated with local RAS inhibition.

DOI： 10.1038/ki.2014.220

Language：English   Publishing type：Research paper (scientific journal)  

AIMS: We previously reported that chronic uremia induces spatial working memory dysfunction in mice, and that it is attributed to cerebral oxidative stress. The source of oxidative stress was considered to be uremic toxins, but this remains unclear. In the present study, we examined whether the brain renin-angiotensin system was activated in the CKD mouse model, and whether it contributed to cognitive impairment. MAIN METHODS: CKD was induced in 8-week-old male mice by 5/6 nephrectomy. Mice were divided into four groups: control mice administered tap water (Cont-V), control mice treated with 0.5mg/kg/day telmisartan, an angiotensin II (AII) receptor blocker, for 8 weeks (Cont-T), CKD mice administered tap water (CKD-V), and CKD mice treated with 0.5 mg/kg/day telmisartan for 8 weeks (CKD-T). After the treatment period, a radial arm water maze (RAWM) test was performed, and angiotensin II (AII) concentrations and markers of oxidative stress were measured in the brains of mice. KEY FINDINGS: Errors in the RAWM test were more frequent in the CKD-V group than in the Cont-V group. In addition, errors in the CKD-T group were comparable to control mice. Tissue brain AII concentrations were greater in the CKD-V group compared with the other groups. Oxidative DNA damage and lipid peroxidation in the brain were also greater in the CKD-V group compared with the other groups. SIGNIFICANCE: Our results suggest that brain AII levels were exaggerated in CKD mice, and that this contributes to cognitive impairment through oxidative stress.

DOI： 10.1016/j.lfs.2014.07.032

Language：English   Publishing type：Research paper (scientific journal)  

Aims We previously reported that chronic uremia induces spatial working memory dysfunction in mice, and that it is attributed to cerebral oxidative stress. The source of oxidative stress was considered to be uremic toxins, but this remains unclear. In the present study, we examined whether the brain renin-angiotensin system was activated in the CKD mouse model, and whether it contributed to cognitive impairment. Main methods CKD was induced in 8-week-old male mice by 5/6 nephrectomy. Mice were divided into four groups: control mice administered tap water (Cont-V), control mice treated with 0.5 mg/kg/day telmisartan, an angiotensin II (AII) receptor blocker, for 8 weeks (Cont-T), CKD mice administered tap water (CKD-V), and CKD mice treated with 0.5 mg/kg/day telmisartan for 8 weeks (CKD-T). After the treatment period, a radial arm water maze (RAWM) test was performed, and angiotensin II (AII) concentrations and markers of oxidative stress were measured in the brains of mice. Key findings Errors in the RAWM test were more frequent in the CKD-V group than in the Cont-V group. In addition, errors in the CKD-T group were comparable to control mice. Tissue brain AII concentrations were greater in the CKD-V group compared with the other groups. Oxidative DNA damage and lipid peroxidation in the brain were also greater in the CKD-V group compared with the other groups. Significance Our results suggest that brain AII levels were exaggerated in CKD mice, and that this contributes to cognitive impairment through oxidative stress.

DOI： 10.1016/j.lfs.2014.07.032

Language：English   Publishing type：Research paper (scientific journal)  

UNLABELLED: Acute liver failure is associated with significant mortality. However, the underlying pathophysiological mechanism is not yet fully understood. Suppressor of cytokine signaling-1 (SOCS1), which is a negative-feedback molecule for cytokine signaling, has been shown to be rapidly induced during liver injury. Here, using liver-specific SOCS1-conditional-knockout mice, we demonstrated that SOCS1 deletion in hepatocytes enhanced concanavalin A (ConA)-induced hepatitis, which has been shown to be dependent on activated T and natural killer T (NKT) cells. Although serum cytokine level and NKT cell activation were similar in wild-type (WT) and SOCS1-deficient mice after ConA treatment, proapoptotic signals, including signal transducers and activators of transcription 1 (STAT1) and Jun-terminal kinase (JNK) activation, were enhanced in SOCS1-deficient livers compared with those in WT livers. SOCS1-deficient hepatocytes had higher expression of Fas antigen and were more sensitive to anti-Fas antibody-induced apoptosis than were WT hepatocytes. Furthermore, SOCS1-deficient hepatocytes were more sensitive to tumor necrosis factor (TNF)-alpha-induced JNK activation and apoptosis. These data indicate that SOCS1 is important to the prevention of hepatocyte apoptosis induced by Fas and TNF-alpha. In contrast, SOCS1 overexpression in the liver by adenoviral gene transfer prevented ConA-induced liver injury. CONCLUSION: These findings indicate that SOCS1 plays important negative roles in fulminant hepatitis and that forced expression of SOCS1 is therapeutic in preventing hepatitis.

DOI： 10.1002/hep.22214

Language：English   Publishing type：Research paper (scientific journal)  

Acute liver failure is associated with significant mortality. However, the underlying pathophysiological mechanism is not yet fully understood. Suppressor of cytokine signaling-1 (SOCS1), which is a negative-feedback molecule for cytokine signaling, has been shown to be rapidly induced during liver injury. Here, using liver-specific SOCS1-conditional-knockout mice, we demonstrated that SOCS1 deletion in hepatocytes enhanced concanavalin A (ConA)-induced hepatitis, which has been shown to be dependent on activated T and natural killer T (NKT) cells. Although serum cytokine level and NKT cell activation were similar in wild-type (WT) and SOCS1-deficient mice after ConA treatment, proapoptotic signals, including signal transducers and activators of transcription 1 (STAT1) and Jun-terminal kinase (JNK) activation, were enhanced in SOCS1-deficient fivers compared with those in WT livers. SOCS1-deficient hepatocytes had higher expression of Fas antigen and were more sensitive to anti-Fas antibody-induced apoptosis than were WT hepatocytes. Furthermore, SOCS1-deficient hepatocytes were more sensitive to tumor necrosis factor (TNF)-α-induced JNK activation and apoptosis. These data indicate that SOCS1 is important to the prevention of hepatocyte apoptosis induced by Fas and TNF-α. In contrast, SOCS1 overexpression in the liver by adenoviral gene transfer prevented ConA-induced fiver injury. Conclusion: These findings indicate that SOCS1 plays important negative roles in fulminant hepatitis and that forced expression of SOCS1 is therapeutic in preventing hepatitis.

DOI： 10.1002/hep.22214

Language：English   Publishing type：Research paper (scientific journal)  

We cloned cDNA and genomic DNA containing exon 1 of mouse Neil3. Neil3 spans 52.4 kb and consists of 10 exons. Northern blot analysis revealed that Neil3 mRNA was selectively expressed in thymus, spleen and bone marrow. High levels of Neil3 mRNA were also detected in various mouse B cell lines by RT-PCR. Immunofluorescence microscopy using anti-NEIL3 revealed that recombinant mouse NEIL3 is localized in the nuclei. In mouse splenocytes, the level of Neil3 mRNA significantly increased after mitogen stimulation in vitro. We established NEIL3-null mice, which are viable and fertile. We found candidate sequences for NEIL3 orthologues in a DNA database from dog and zebrafish in addition to human and mouse, but not invertebrates. NEIL3 may function exclusively in vertebrates, such as mammals.

Language：English   Publishing type：Research paper (scientific journal)  

In the mouse genome, we found one processed Itpa gene-like sequence and two processed Itpa pseudogenes as well as the Itpa gene itself with introns, located on chromosome 2F3, which was isolated by a retro-recombination method. We also identified three types (A, B, C) of Itpa transcripts in mouse tissues. The processed Itpa gene-like sequence located on chromosome 2E1 has a complete open reading frame for exactly the same polypeptide as ITPA encoded by the type A transcript, with a polyadenylation signal. However, no transcribed sequence derived from the Itpa gene-like sequence was detectable in any of the mouse tissues examined, thus naming the sequence as Itpa processed pseudogene alpha. The type A Itpa mRNA, which was expressed in all mouse tissues examined, only encodes mouse ITPA polypeptide consisting of 198 amino acid residues with a capacity to hydrolyze dITP into dIMP. Itpa mRNA was detected in all tissues examined, and its expression is especially high in the testis, brain, and thymus. ITPA protein was mostly detected in the cytoplasm, to a lesser extent in the nuclei of neurons in the brain, and also those of hepatocytes, epithelial cells lining the bile duct, and endothelial cells lining the portal vein in the liver.

Language：English   Publishing type：Research paper (scientific journal)  

In the mouse genome, we found one processed Itpa gene-like sequence and two processed Itpa pseudogenes as well as the Itpa gene itself with introns, located on chromosome 2F3, which was isolated by a retrorecombination method. We also identified three types (A, B, C) of Itpa transcripts in mouse tissues. The processed Itpa gene-like sequence located on chromosome 2E1 has a complete open reading frame for exactly the same polypeptide as ITPA encoded by the type A transcript, with a polyadenylation signal. However, no transcribed sequence derived from the Itpa gene-like sequence was detectable in any of the mouse tissues examined, thus naming the sequence as Itpa processed pseudogene α. The type A Itpa mRNA, which was expressed in all mouse tissues examined, only encodes mouse ITPA polypeptide consisting of 198 amino acid residues with a capacity to hydrolyze dITP into dIMP. Itpa mRNA was detected in all tissues examined, and its expression is especially high in the testis, brain, and thymus. ITPA protein was mostly detected in the cytoplasm, to a lesser extent in the nuclei of neurons in the brain, and also those of hepatocytes, epithelial cells lining the bile duct, and endothelial cells lining the portal vein in the liver.

DOI： 10.1093/dnares/12.1.39

Event date： 2014.11

Language：English  

Venue：Philadelphia   Country：United States  

Background: Proteinuria (PU) is widely used as a marker for renal prognosis in clinical setting, as well as urinary angiotensinogen (U-AGT). Our preliminary data confi rmed that patients with focal segmental glomerulosclerosis (FSGS) represented higher U-AGT/urinary protein (UP) ratio than patients with minimal change disease (MCD) (3.1 ± 1.3 versus 0.7 ± 0.3 g/10mg UP) and showed AGT deposition in segmental lesions of glomeruli, suggesting U-AGT is a more specifi c marker of podocyte injury than PU. Methods: We tested the impacts of U-AGT and PU on two different nephrotic models induced by puromycin aminonucleoside (PAN) in Wistar rats; 15 mg/100 g·body weight (BW) of PAN administration at week 0 similar to MCD, and 5 mg/100 g·BW of PAN administration for three times at weeks 0, 1 and 2 similar to FSGS. Next, we observed renal tissue and urinary metabolism of exogenous injected human recombinant AGT (hAGT; little affi nity for enzymatic cleavage by rodent renin) in FSGS and control rats. Furthermore, we tested AGT production levels in cultured mouse podocytes injured by PAN. Results: PU levels were comparable between MCD and FSGS rats. U-AGT levels from FSGS rats were higher than MCD rats, and podocin and nephrin expressions were reduced in FSGS, but not in MCD rats. Intravenous injection of hAGT showed about 100-fold increases in urinary hAGT excretion from FSGS rats compared to undetectable levels of those from control rats. Immunostaining for rat-AGT and hAGT identifi ed that rat-AGT was detected in injured podocytes as well as proximal tubules, but fi ltrated hAGT was detected only in superfi cial proximal tubules. Finally, we confi rmed that PAN induced increases in AGT production in cultured podocytes in dose dependent manner and these were negatively associated with podocin and synaptopodin expression in podocytes. Conclusions: U-AGT, which was affected by AGT produced from injured podocytes at least in part, in addition to exogenous fi ltrated AGT from glomeruli, is a reliable marker of podocyte injury.

Event date： 2014.11

Language：English  

Venue：Philadelphia   Country：United States  

Background: The interaction between lymphangiogenesis and renal injury has been shown in chronic kidney disease (CKD); however, the precise role of lymphangiogenesis in renal injury remains unknown. The lymphatic network is responsible for the removal of interstitial protein and fl uid. In the present study, we investigated the interaction between lymphangiogenesis and renal interstitial infl ammation and fi brosis using unilateral ureteral obstruction (UUO) model mice. Methods: Seven-week-old male C57BL6 mice were divided into the 3 groups; the control mice (Con, n=5), UUO mice (UUO, n=5), and UUO mice administrated vascular endothelial growth factor-C (VEGF-C), an inducer of lymphangiogenesis (UUO+VEGF-C, n=5). VEGF-C was administered at a dose of 100 μg/kg/day using osmotic pumps for 14 days. We investigated lymphangiogenesis (anti-LYVE-1 immunostaining), interstitial fi brosis (Sirius red staining), expression levels of fi brosis-related gene [Collagen I mRNA and a-smooth muscle actin (a-SMA) protein], and macrophage infi ltration (anti-F4/80 immunostaining) in each group. Results: In UUO mice, along with progression of interstitial fi brosis, the density of lymph vessels, the levels of VEGF-receptor 3 (VEGF-R3) mRNA, Collagen I mRNA, and a-SMA protein, and macrophage infi ltration increased with time in the obstructed kidney. In UUO+VEGF-C mice, the density of lymph vessels (1.21-fold, p=0.3) and the level of VEGF-R3 protein (2.18-fold, p

Event date： 2014.11

Language：English  

Venue：Philadelphia   Country：United States  

Background: Recent studies have indicated a protective role of autophagy in calcifi cation of vascular smooth muscle cells, but the mechanisms are poorly understood. Calciprotein particles (CPP) are cytotoxic nanoparticles composed of inorganic calciumphosphate crystals and mineral binding proteins, such as fetuin-A. CPP circulate in the blood of patients with chronic kidney disease and may contribute to vascular calcifi cation, chronic infl ammation and a premature-aging phenotype. However, little is known about the effect of CPP on smooth muscle cells. We studied the role of autophagy in vascular calcifi cation induced by phosphate and CPP. Methods: We used primary human aortic smooth muscle cells (hAoSMC) to assess CPP-induced autophagy and calcifi cation. We made CPP from Dulbecco’s Modifi ed Eagle Medium containing 10% fetal bovine serum, 5 mM phosphate, and 10 mM calcium. We also prepared CPP containing Alexa488-labeled Fetuin-A, and observed localization of CPP and LC3 in hAoSMC using confocal microscope. For high phosphate condition, we incubated cells in the presence of 4 mM phosphate. Calcifi cation was analyzed by von Kossa staining. Induction of autophagy was detected by western blot and immunofl uorescence. Results: High phosphate obviously induced endogenous LC3 puncta in hAoSMCs. In electron microscopy, we observed calcium phosphate crystal-like substances in autophagic structures in hAoSMCs under high phosphate. CPP induced calcifi cation of hAoSMC in concentration-dependent manner. Consistent with high phosphate condition, CPP induced autophagy in hAoSMCs. The conversion of LC3-I to LC3-II in western blot and endogenous LC3 puncta formation were induced. Furthermore, we found that a small part of CPP containing labeled fetuin-A localized in LC3-labeled autophagosome under laser confocal microscope. Conclusions: Phosphate or CPP induce autophagy and calcifi cation in hAoSMC. And some calcium phosphate crystal or CPP localized in autophagosome. Autophagy may regulate CPP transport or dissolution in smooth muscle cells.

Event date： 2014.7

Language：Japanese  

Venue：パシフィコ横浜   Country：Japan  

【目的】腎線維化の進行に伴いリンパ管が増生することが報告されている．今回我々は，片側尿管結紮(UUO)モデルを用いて，リンパ管新生に関与する血管内皮増殖因子 Vascular endothelial growth factor-C (VEGF-C)の腎線維化への関与について検討した．【方法】7週齢の雄性C57BL6マウスにUUO術を施行し，同時にVEGF-Cを持続投与した群(U+VC群，n=5)と無投与群(U群，n=5)において，リンパ管新生(LYVE-1染色)，間質線維化(Sirius red染色)および線維化関連遺伝子発現(collagen I mRNA,αSMA蛋白)，マクロファージ浸潤(F4/80染色)を比較検討した．【結果】U群では経時的にリンパ管増生，VEGF-R3 mRNA発現亢進，線維化進行、Collagen I mRNA及びαSMA蛋白の発現亢進，マクロファージ浸潤の増加が認められた．一方，U+VC群では，U群に比べ，リンパ管増生の亢進傾向，VEGF-R3蛋白の発現亢進(2.18倍 ,p＜0.05)に伴い，Collagen I mRNA発現の抑制(0.45倍 ,p＜0.05)，αSMA蛋白発現の抑制傾向とともに，間質線維化は軽減(0.53倍, p＜0.01)した．【結論】VEGF-C投与によりリンパ管新生が促進され，腎間質の炎症と線維化が抑制された．

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Language：English   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

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Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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