Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Arimura Koichi Last modified date:2019.06.18

Assistant Professor / Neurological Institute / Faculty of Medical Sciences


Papers
1. Osamu Togao, Hiwatashi Akio, Koji Yamashita, Daichi Momosaka, Makoto Obara, ataru nishimura, Koichi Arimura, Nobuhiro Hata, Koji Iihara, Marc Van Cauteren, Hiroshi Honda, Acceleration-selective arterial spin labeling MR angiography for visualization of brain arteriovenous malformations, Neuroradiology, 10.1007/s00234-019-02217-w, 2019.01, Purpose: To evaluate the performance of acceleration-selective arterial spin labeling (AccASL) MR angiography in the visualization of brain arteriovenous malformations (AVMs) in comparison with digital subtraction angiography (DSA) and time-of-flight (TOF) MR angiography. Methods: Twenty-one patients with brain AVM (mean age 31.1 ± 18.6 years; 11 males, 10 females) underwent TOF and AccASL MR angiography and DSA. Two neuroradiologists conducted an observer study for detection, nidus size, eloquence, venous drainage pattern, and Spetzler-Martin (SM) grade. The evaluations included the visualization of each AVM component with reference to DSA and assessments of contrast-to-noise ratio (CNR). The kappa statistic, repeated measures analysis of variance, Wilcoxon matched pairs test, and paired t test were used. Results: Both observers detected more AVMs with AccASL (95.2%, 90.5% for Observers 1 and 2) than with TOF (76.2% and 71.4%, respectively). The inter-modality agreement between AccASL and DSA was almost perfect for the eloquence, venous drainage pattern, and SM grade for Observer 1 and moderate for the venous drainage pattern and substantial for the eloquence and SM grade for Observer 2. The visualization scores were higher with AccASL than with TOF for the feeding artery (AccASL, 4.5 ± 1.0 vs. TOF, 3.9 ± 1.5, p = 0.0214), nidus (4.6 ± 1.1 vs. 3.2 ± 1.5, p = 0.0006), and draining vein (4.6 ± 1.0 vs. 2.2 ± 1.1, p < 0.0001), respectively. The CNRs in the nidus were higher in AccASL than in TOF (29.9 ± 16.7 vs. 20.8 ± 16.5, p = 0.0002), as in the draining vein (23.2 ± 13.0 vs. 12.6 ± 12.0, p = 0.0010), respectively. Conclusions: AccASL better visualized brain AVMs compared with TOF and was useful for grading without the use of contrast agents..
2. Nobuyuki Sakai, Hirotoshi Imamura, Koichi Arimura, Takayuki Funatsu, Mikiya Beppu, Keita Suzuki, Hiromasa Adachi, Tomohiro Okuda, Yuichi Matsui, Shuhei Kawabata, Ryo Akiyama, Kazufumi Horiuchi, Shoichi Tani, Hidemitsu Adachi, Chiaki Sakai, Naoki Kaneko, Satoshi Tateshima, PulseRider-Assisted Coil Embolization for Treatment of Intracranial Bifurcation Aneurysms
A Single-Center Case Series with 24-Month Follow-up, World Neurosurgery, 10.1016/j.wneu.2019.04.177, 2019.01, Background: Although endovascular coiling of unruptured aneurysms is widely accepted, the endovascular treatment of wide-neck bifurcation aneurysms remains one of the most challenging morphologies. Our purpose was to describe our experience with 24-month follow-up for the treatment of unruptured intracranial bifurcation aneurysms using the PulseRider (Cerenovus, New Brunswick, NJ). Methods: This study is a single-center, single-arm registry performed under institutional review board control to evaluate efficacy and safety of the PulseRider. Patients with bifurcation aneurysms were identified and enrolled prospectively. Angiography immediately after treatment and at 6 months, and magnetic resonance imaging and magnetic resonance angiography at 12- and 24-month follow-up were retrospectively analyzed. A modified Rankin score was obtained prior to procedure, at discharge, and at 6-, 12- and 24-month follow-up visits. Results: Eight patients with a mean age of 66 years were treated with the PulseRider. All patients had bifurcation aneurysms (2 anterior communicating, 2 carotid terminus, and 4 basilar apex). The aneurysm diameters ranged from 4.6 to 13.6 mm (mean 7.4 mm) with dome/neck ratio ranging from 1.4 to 2.2 (mean 1.6). In all cases, the PulseRider was successfully deployed. Complete occlusion was demonstrated at 6-month follow-up on 6 of 8 (75%), near complete occlusion in 1 of 8 (12.5%), and residual aneurysm in 1 of 8 (12.5%) patients. There was no change or recurrence on magnetic resonance angiography, nor clinical complication after the procedure through 24-month follow-up. Conclusions: Our experience with 24-month follow-up demonstrated favorable efficacy in the treatment of intracranial wide-neck bifurcation aneurysms using the PulseRider..
3. Kenichi Todo, Nobuyuki Sakai, Hirotoshi Imamura, Hiroshi Yamagami, Hidemitsu Adachi, Tomoyuki Kono, Junya Kobayashi, Shiro Yamamoto, Takeshi Morimoto, Shoichi Tani, Michi Kawamoto, Manabu Sakaguchi, Yasushi Ueno, Takeharu Kunieda, Osamu Narumi, Chiaki Sakai, Akira Ishii, Taku Hoshi, Masaomi Koyanagi, Yohei Mineharu, Tatsuya Ishikawa, Yoji Kuramoto, Shinsuke Sato, Nobuyuki Ohara, Koichi Arimura, Hajime Nakamura, Takeo Nishida, Yasufumi Gon, Toshiyuki Fujinaka, Kazuhisa Yoshiya, Haruhiko Kishima, Hideki Mochizuki, Nobuo Kohara, Successful Reperfusion with Endovascular Therapy Has Beneficial Effects on Long-Term Outcome beyond 90 Days, Cerebrovascular Diseases, 10.1159/000499190, 2019.01, Background and Purpose: Recent studies have demonstrated that endovascular reperfusion therapy improves clinical outcomes at 90 days after ischemic stroke. However, the effects on long-term outcomes are not well known. We hypothesized that successful reperfusion might be associated with long-term improvement beyond 90 days after endovascular therapy. To assess the long-term effects beyond 90 days, we analyzed the association of successful reperfusion with a temporal change in modified Rankin Scale (mRS) score from 90 days to 1 year after endovascular therapy. >bold<>italic/italic<>/bold< We retrospectively analyzed a database of consecutive patients with acute ischemic stroke who received endovascular therapy between April 2006 and March 2016 at 4 centers. We compared the incidences of improvement and deterioration in patients with successful reperfusion (i.e., modified thrombolysis in cerebral infarction score of 2b or 3) with those in patients with unsuccessful reperfusion. We defined improvement and deterioration as decrease and increase on the mRS score by 1 point or more from 90 days to 1 year after endovascular therapy respectively. >bold<>italic/italic<>/bold< A total of 268 patients were included in the current study. The rate of patients with improvement tended to be higher in patients with successful reperfusion than in patients with unsuccessful reperfusion (20% [34/167 patients] vs. 12% [12/101], >italic
/italic< = 0.07). The rate of patients with deterioration was lower in patients with successful reperfusion than in patients with unsuccessful reperfusion (25% [42/167] vs. 42% [42/101], >italic
/italic< < 0.01). After adjustment for confounders, successful reperfusion was associated with improvement (adjusted OR 2.65; 95% CI 1.23-5.73; >italic
/italic< < 0.05) and deterioration (adjusted OR 0.33; 95% CI 0.18-0.62; >italic
/italic< < 0.01), independent of the 90-day mRS score. >bold<>italic/italic<>/bold< Successful reperfusion has further beneficial legacy effects on long-term outcomes beyond 90 days after stroke..
4. Osamu Togao, Hiwatashi Akio, Makoto Obara, Koji Yamashita, Daichi Momosaka, ataru nishimura, Koichi Arimura, Nobuhiro Hata, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda, 4D ASL-based MR angiography for visualization of distal arteries and leptomeningeal collateral vessels in moyamoya disease
a comparison of techniques, European Radiology, 10.1007/s00330-018-5462-7, 28, 11, 4871-4881, 2018.11, Objectives: To evaluate the performance of four-dimensional pseudo-continuous arterial spin labeling (4D-pCASL)-based angiography using CENTRA-keyhole and view sharing (4D-PACK) in the visualization of flow dynamics in distal cerebral arteries and leptomeningeal anastomosis (LMA) collaterals in moyamoya disease in comparison with contrast inherent inflow-enhanced multiphase angiography (CINEMA), with reference to digital subtraction angiography (DSA). Methods: Thirty-two cerebral hemispheres from 19 patients with moyamoya disease (mean age, 29.7 ± 19.6 years; five males, 14 females) underwent both 4D-MR angiography and DSA. Qualitative evaluations included the visualization of anterograde middle cerebral artery (MCA) flow and retrograde flow via LMA collaterals with reference to DSA. Quantitative evaluations included assessments of the contrast-to-noise ratio (CNR) on these vessels. The linear mixed-effect model was used to compare the 4D-PACK and CINEMA methods. Results: The vessel visualization scores were significantly higher with 4D-PACK than with CINEMA in the visualization of anterograde flow for both Observer 1 (CINEMA, 3.53 ± 1.39; 4D-PACK, 4.53 ± 0.80; p < 0.0001) and Observer 2 (CINEMA, 3.50±1.39; 4D-PACK, 4.31 ± 0.86; p = 0.0009). The scores were higher with 4D-PACK than with CINEMA in the visualization of retrograde flow for both Observer 1 (CINEMA, 3.44 ± 1.05; 4D-PACK, 4.47 ± 0.88; p < 0.0001) and Observer 2 (CINEMA, 3.19 ± 1.20; 4D-PACK, 4.38 ± 0.91; p < 0.0001). The maximum CNR in the anterograde flow was higher in 4D-PACK (40.1 ± 16.1, p = 0.0001) than in CINEMA (27.0 ± 16.6). The maximum CNR in the retrograde flow was higher in 4D-PACK (36.1 ± 10.0, p < 0.0001) than in CINEMA (15.4 ± 8.0). Conclusions: The 4D-PACK provided better visualization and higher CNRs in distal cerebral arteries and LMA collaterals compared with CINEMA in patients with this disease. Key Points: • The 4D-PACK enables good visualization of distal cerebral arteries in moyamoya disease. • The 4D-PACK enables direct visualization of leptomeningeal collateral vessels in moyamoya disease. • Vessel visualization by 4D-PACK can be useful in assessing cerebral hemodynamics..
5. Mikiya Beppu, Yohei Mineharu, Hirotoshi Imamura, Hidemitsu Adachi, Chiaki Sakai, Shoichi Tani, Koichi Arimura, So Tokunaga, Nobuyuki Sakai, Postoperative in-stent protrusion is an important predictor of perioperative ischemic complications after carotid artery stenting, Journal of Neuroradiology, 10.1016/j.neurad.2018.02.009, 45, 6, 357-361, 2018.10, Background and purpose: Although in-stent protrusion is a potential risk factor for thromboembolism following carotid artery stenting, the correlation between in-stent protrusion and postoperative ipsilateral stroke has not been well examined. Materials and methods: We retrospectively reviewed 342 consecutive carotid artery lesions in 319 patients who underwent carotid artery stenting between April 2008 and April 2015. After excluding cases with carotid artery dissection and acute occlusion, 301 lesions in total of 277 patients were included in the analysis. We examined the association between in-stent protrusion, which was detected by intravascular ultrasound, and postoperative ipsilateral stroke within 30 days. Results: In-stent protrusion was observed in 47 (15.6%) lesions, of which postoperative ipsilateral stroke within 30 days occurred with 4 (8.5%) lesions. All these events occurred within 10 days after treatment. On the other hand, only 1 (0.39%) of the 256 lesions without in-stent protrusion showed this symptom, and the event occurred at 30 days after treatment. Thus, lesions with in-stent protrusion had a higher cumulative risk of ipsilateral stroke than those without in-stent protrusion (8.5% vs 0.4% at 30 days, log-rank P < 0.001). In-stent protrusion, which was more often seen in symptomatic lesions, was associated with a vulnerable plaque assessed by MRI. After adjustment for postoperative stroke risks such as symptomatic lesions, plaque vulnerability, age or sex, in-stent protrusion was still significantly associated with postoperative ipsilateral stroke within 30 days (OR = 27.03, P = 0.001). Conclusions: Postoperative ipsilateral stroke was observed more frequently in patients with demonstrated in-stent protrusion (ISP) following CAS..
6. Tomohiro Okuda, Nobuhiro Hata, Satoshi Suzuki, Koji Yoshimoto, Koichi Arimura, Takeo Amemiya, Yojiro Akagi, Daisuke Kuga, Utako Oba, Yuhki Koga, Shoichi Ohga, Toru Iwaki, Koji Iihara, Pediatric ganglioglioma with an H3 K27M mutation arising from the cervical spinal cord, Neuropathology, 10.1111/neup.12471, 38, 4, 422-427, 2018.08, The 2016 edition of the World Health Organization Classification of Tumors of the Central Nervous System introduced “diffuse midline glioma H3 K27M mutant” as a new diagnostic entity. These tumors predominately affect pediatric patients and arise from midline structures such as the brainstem, thalamus and spinal cord. Here, we report a rare patient with spinal ganglioglioma carrying an H3 K27M mutation. A 10-year-old boy presented with an intramedullary tumor in the cervical spinal cord. The lesion was partially removed and histologically diagnosed as ganglioglioma. After the remnant tumor grew within 3 months after surgery, the patient underwent radiotherapy. Genetic analyses revealed an H3F3A K27M mutation but no other genetic alterations such as IDH and BRAF mutations. This case may point to pathological heterogeneity in gliomas with H3 K27M mutations..
7. Ryota Kurogi, Kunihiro Nishimura, Michikazu Nakai, Akiko Kada, Satoru Kamitani, Jyoji Nakagawara, Kazunori Toyoda, Kuniaki Ogasawara, Junichi Ono, Yoshiaki Shiokawa, Toru Aruga, Shigeru Miyachi, Izumi Nagata, Shinya Matsuda, Shinichi Yoshimura, Kazuo Okuchi, Akifumi Suzuki, Fumiaki Nakamura, Daisuke Onozuka, Keisuke Ido, Ai Kurogi, Nobutaka Mukae, Ataru Nishimura, Koichi Arimura, Takanari Kitazono, Akihito Hagihara, Koji Iihara, Comparing intracerebral hemorrhages associated with direct oral anticoagulants or warfarin, Neurology, 10.1212/WNL.0000000000005207, 90, 13, e1143-e1149, 2018.03, Objectives This cross-sectional survey explored the characteristics and outcomes of direct oral anticoagulant (DOAC)-associated nontraumatic intracerebral hemorrhages (ICHs) by analyzing a large nationwide Japanese discharge database. Methods We analyzed data from 2,245 patients who experienced ICHs while taking anticoagulants (DOAC: 227; warfarin: 2,018) and were urgently hospitalized at 621 institutions in Japan between April 2010 and March 2015. We compared the DOAC-and warfarin-treated patients based on their backgrounds, ICH severities, antiplatelet therapies at admission, hematoma removal surgeries, reversal agents, mortality rates, and modified Rankin Scale scores at discharge. Results DOAC-associated ICHs were less likely to cause moderately or severely impaired consciousness (DOAC-associated ICHs: 31.3%; warfarin-associated ICHs: 39.4%; p = 0.002) or require surgical removal (DOAC-associated ICHs: 5.3%; warfarin-associated ICHs: 9.9%; p = 0.024) in the univariate analysis. Propensity score analysis revealed that patients with DOAC-associated ICHs also exhibited lower mortality rates within 1 day (odds ratio [OR] 4.96, p = 0.005), within 7 days (OR 2.29, p = 0.037), and during hospitalization (OR 1.96, p = 0.039). Conclusions This nationwide study revealed that DOAC-treated patients had less severe ICHs and lower mortality rates than did warfarin-treated patients, probably due to milder hemorrhages at admission and lower hematoma expansion frequencies..
8. Osamu Togao, Hiwatashi Akio, Makoto Obara, Koji Yamashita, kazufumi kikuchi, Ryotaro Kamei, ataru nishimura, Koichi Arimura, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda, Acceleration-selective arterial spin-labeling MR angiography used to visualize distal cerebral arteries and collateral vessels in moyamoya disease, Radiology, 10.1148/radiol.2017162279, 286, 2, 611-621, 2018.02, Purpose: To evaluate and compare the performance of accelerationselective arterial spin labeling (AccASL) magnetic resonance (MR) angiography in the visualization of cerebral arteries and collateral vessels in patients with Moyamoya disease with that of time-of-flight (TOF) MR angiography, with digital subtraction angiography (DSA) as the reference standard. Materials and Methods: Thirty-six cerebral hemispheres from 22 patients with Moyamoya disease underwent TOF and AccASL MR angiography and DSA. Qualitative evaluations included imaging of the terminal internal carotid artery (ICA), distal middle cerebral arteries (MCAs), Moyamoya vessels, and leptomeningeal anastomosis (LMA) collaterals with reference to DSA. Quantitative evaluations included assessment of contrast-tonoise ratio (CNR) and number of vessels in MCA branches. The linear mixed-effect model was used to compare the two methods. Results: Mean scores for qualitative evaluation were significantly higher with AccASL angiography than with TOF angiography for imaging distal MCAs (3.9 6 0.3 [standard deviation] vs 2.9 6 1.1; P , .001), Moyamoya vessels (3.6 6 0.6 vs 2.7 6 0.9, P , .001), and LMA collaterals (3.8 6 0.6 vs 1.8 6 0.7, P , .001). Scores for steno-occlusive degree around the terminal ICAs were better with TOF angiography than with AccASL angiography (2.6 6 0.5 vs 2.4 6 0.6, P = .023). CNRs in the M4 segment were significantly higher with AccASL angiography (11.9 6 12.9, P , .001) than with TOF angiography (4.1 6 7.9). The number of vessels was significantly higher with AccASL angiography (18.3 6 5.0, P , .001) than with TOF angiography (8.9 6 4.9). The increase in the number of vessels from TOF angiography to AccASL angiography was greater in patients with severe ICA stenoocclusion (late ICA stage group, 11.4 6 4.5; early ICA stage group, 6.8 6 4.0; P = .007) and well-developed leptomeningeal anastomosis (mildly developed LMA group, 7.1 6 4.3; well-developed LMA group, 11.3 6 4.5; P = .011). Conclusion: AccASL MR angiography enables better visualization of distal cerebral arteries and collateral vessels in patients with Moyamoya disease than does TOF MR angiography, while TOF MR angiography enables better visualization of stenosis of proximal arteries. Both methods work in a mutually beneficial manner in the assessment of cerebral arteries..
9. Toyoshi Yanagihara, Nanae Seki, Hiwatashi Akio, Koichi Arimura, Satoshi Suzuki, Isamu Okamoto, Metastatic lung adenocarcinoma mimicking meningioma, Internal Medicine, 10.2169/internalmedicine.9472-17, 57, 7, 1057-1058, 2018.01.
10. Kenji Miki, Koichi Arimura, ataru nishimura, Koji Yoshimoto, Tetsuro Sayama, Koji Iihara, Revascularization Operation for Moyamoya Disease with Concurrent von Willebrand Disease, World Neurosurgery, 10.1016/j.wneu.2017.08.141, 108, 991.e17-991.e21, 2017.12, Background Although extracranial-intracranial (EC-IC) bypass is an effective treatment strategy for symptomatic moyamoya disease, surgeons need to be cautious regarding the possibility of postoperative hemorrhagic complications in patients with a concurrent coagulation disorder. Here, we describe a case of EC-IC bypass for moyamoya disease concurrent with von Willebrand disease type 1. Case Description Following perioperative replacement of the von Willebrand factor, the patient showed an uneventful and uncomplicated clinical course. Conclusion This is the first reported case of EC-IC bypass being performed for moyamoya disease in a patient with concurrent von Willebrand disease. We emphasize the importance of appropriate management with replacement of the von Willebrand factor during the perioperative period to avoid hemorrhagic complications..
11. Arimura K, Imamura H, Todo K, Tani S, Adachi H, Hoshi T, Kono T, Funatsu T, Saito T, Beppu M, Takebe N, Suzuki K, Okuda T, Kawabata S, Matsui Y, Yoshida Y, Sakai N, Intracranial Hemorrhage after Endovascular Revascularization for Acute Ischemic Stroke, J Neuroendovasc Ther, 2017.08.
12. Miki K, Arimura K, Nishimura A, Yoshimoto K, Sayama T, Iihara K., Revascularization Operation for Moyamoya Disease with Concurrent von Willebrand Disease., World Neursurg, 2017.06.
13. Kampei Shimizu, Hirotoshi Imamura, Yohei Mineharu, Hidemitsu Adachi, Chiaki Sakai, Shoichi Tani, Koichi Arimura, Mikiya Beppu, Nobuyuki Sakai, Endovascular parent-artery occlusion of large or giant unruptured internal carotid artery aneurysms. A long-term single-center experience, Journal of Clinical Neuroscience, 10.1016/j.jocn.2016.11.009, 37, 73-78, 2017.03, The development of stent-like devices has increased treatment options for complex internal carotid artery (ICA) aneurysms, but the optimal treatment remains unclear. The purpose of this study was to evaluate the safety and efficacy of endovascular parent-artery occlusion (PAO) for ICA aneurysms. We retrospectively reviewed 28 patients with unruptured ICA aneurysms ⩾10 mm treated with PAO between April 2002 and March 2015 at our institution. Patients who developed neurologic symptoms or with venous-phase delay >2 s during balloon test occlusion were not treated by PAO. Patients with venous-phase delays of 1–2 s underwent superficial temporal artery to middle cerebral artery (STA-MCA) bypass prior to PAO. The median patient age was 65 (range, 26–84) years. Nineteen aneurysms (68%) were located in the cavernous segment. The median aneurysm size was 25 (range 11–40) mm. Venous-phase delay of 1–2 s was observed in five patients. Perioperative ischemic complications (N = 9, 32%), which occurred within 30 days after treatment, were significantly associated with venous-phase delays of 1–2 s (p < 0.01) and history of hypertension (p < 0.01). Six-month morbidity was observed in one (3.6%) patient. Complete occlusion at final follow-up and delayed (i.e. ⩾31 days after treatment) ischemic events were observed in 100% and 0% of patients, respectively, over a median period of 63 (range, 6–147) months. Despite the high frequency of perioperative ischemic episodes, endovascular PAO with selective use of STA-MCA bypass showed excellent long-term outcomes in patients with unruptured ICA aneurysms ⩾10 mm..
14. Satoshi Karashima, Koichi Arimura, Kimiaki Hashiguchi, Yojiro Akagi, Nobutaka Mukae, ataru nishimura, Daisuke Kuga, Koji Yoshimoto, Tetsuro Sayama, Satoshi Suzuki, Koji Iihara, A case of concurrent schwannoma and meningioma at the same cervical level, Japanese Journal of Neurosurgery, 10.7887/jcns.26.750, 26, 10, 750-756, 2017.01, Concurrent spinal tumors such as schwannomas and meningiomas are usually associated with neurofibromatosis type 2(NF2). Here we report an extremely rare case of concurrent schwannoma and meningioma at the same cervical spinal level. This patient did not meet the diagnostic criteria for NF2. Because the surgical strategy for spinal schwannomas may differ if meningiomas are concurrently present, it is important to pay attention to preoperative imaging findings. Unlike in previous patients, however, it was difficult to diagnose the presence of two different tumors based on preoperative images of the present patient. Preoperative images and intraoperative findings must therefore be carefully assessed to determine whether spinal tumors extending into the intradural and extradural spaces consist of concurrent schwannomas and meningiomas..
15. ataru nishimura, Tetsuro Ago, Junya Kuroda, Koichi Arimura, Masaki Tachibana, Kuniyuki Nakamura, Yoshinobu Wakisaka, Junichi Sadoshima, Koji Iihara, Takanari Kitazono, Detrimental role of pericyte Nox4 in the acute phase of brain ischemia, Journal of Cerebral Blood Flow and Metabolism, 10.1177/0271678X15606456, 36, 6, 1143-1154, 2016.06, Pericytes are mural cells abundantly present in cerebral microvessels and play important roles, including the formation and maintenance of the blood-brain barrier. Nox4 is a major source of reactive oxygen species in cardiovascular cells and modulate cellular functions, particularly under pathological conditions. In the present study, we found that the expression of Nox4 was markedly induced in microvascular cells, including pericytes, in peri-infarct areas after middle cerebral artery occlusion stroke models in mice. The upregulation of Nox4 was greater in a permanent middle cerebral artery occlusion model compared with an ischemia/reperfusion transient middle cerebral artery occlusion model. We performed permanent middle cerebral artery occlusion on mice with Nox4 overexpression in pericytes (Tg-Nox4). Infarct volume was significantly greater with enhanced reactive oxygen species production and blood-brain barrier breakdown in peri-infarct areas in Tg-Nox4, compared with littermate controls. In cultured brain pericytes, Nox4 was significantly upregulated by hypoxia and was promptly downregulated by reoxygenation. Phosphorylation of NFκ B and production of matrix metalloproteinase 9 were significantly increased in both cultured pericytes overexpressing Nox4 and in peri-infarct areas in Tg-Nox4. Collectively, Nox4 is upregulated in pericytes in peri-infarct areas after acute brain ischemia and may enhance blood-brain barrier breakdown through activation of NFκ B and matrix metalloproteinase 9, thereby causing enlargement of infarct volume..
16. Koichi Arimura, Koji Iihara, New evidences of neuroendovascular therapy for acute ischemic stroke, Nippon rinsho. Japanese journal of clinical medicine, 74, 4, 621-626, 2016.04, Recently, several new randomized controlled trials have been reported which showed the efficacy of neuroendovascular therapy for acute ischemic stroke. Confirming the major vessel occlusion in the proximal anterior circulation, limited ischemic core and preserved ischemic penumbra, using stent retrievers to achieve successful reperfusion, and shortening the onset-to-reperfusion time were the essential factors to achieve good clinical outcome. With these new evidences, it has been proved that neuroendovascular therapy became one of the standard treatments for acute ischemic stroke..
17. Kuniyuki Nakamura, Arimura Koichi, Ataru Nishimura, Possible involvement of basic FGF in the upregulation of PDGFRβ in pericytes after ischemic stroke., Brain Res, 2016.01.
18. Kuniyuki Nakamura, Koichi Arimura, ataru nishimura, Masaki Tachibana, Yoji Yoshikawa, Noriko Makihara, Yoshinobu Wakisaka, Junya Kuroda, Masahiro Kamouchi, Hiroaki Ooboshi, Takanari Kitazono, Tetsuro Ago, Possible involvement of basic FGF in the upregulation of PDGFRβ in pericytes after ischemic stroke, Brain Research, 10.1016/j.brainres.2015.11.003, 1630, 98-108, 2016.01, Central nervous system (CNS) pericytes have been recognized as an indispensable component of the neurovascular unit. The expression of platelet-derived growth factor receptor β (PDGFRβ) is markedly increased in CNS pericytes after brain ischemia. It has been elucidated that PDGFRβ, expressed in pericytes and pericyte-derived fibroblast-like cells, plays important roles in the maintenance of the blood-brain barrier (BBB) and in the repair process in infarct areas. The aim of this study was to uncover how the PDGFRβ expression is regulated in pericytes after brain ischemia. We found that basic fibroblast growth factor (bFGF), but neither hypoxia at 1% O2 nor acidification at pH 6.5, significantly upregulated the PDGFRβ expression in human cultured CNS pericytes. SU5402, an inhibitor of FGF receptor (FGFR), and inhibitors of its downstream effectors Akt and Erk abolished the bFGF-induced upregulation of PDGFRβ. On the other hand, acidification significantly upregulated the expression of bFGF, while hypoxia upregulated the expression of FGFR1 in the pericytes. The expression of bFGF and FGFR1 was markedly induced in the ischemic hemisphere after ischemic insult in a middle cerebral artery occlusion stroke model. Immunofluorescent double labeling demonstrated that the expression of bFGF and FGFR1 was co-localized with PDGFRβ-positive cells in peri-infarct areas. Moreover, treatment with bFGF enhanced cell growth and the PDGF-BB-induced migratory activity of cultured pericytes, which were significantly suppressed by SU5402 or Sunitinib, an inhibitor of PDGFR. These data suggested that increased bFGF upregulates the expression of PDGFRβ and may enhance PDGFRβ-mediated pericyte functions after brain ischemia..
19. Koichi Arimura, Koji Iihara, Surgical management of intracranial artery dissection, Neurologia Medico-Chirurgica, 10.2176/nmc.ra.2015-0312, 56, 9, 517-523, 2016.01, Intracranial artery dissection (IAD) is a relatively rare cause of stroke, but it has been recognized increasingly with recent advances of the neuroimaging technique. Since rebleeding occurs frequently in the acute stage in the ruptured IAD, urgent surgical treatment should be performed to prevent rebleeding. On the other hand, surgical treatment for unruptured IAD is controversial because it has little risk for bleeding. However, surgical treatment for unruptured IAD may be considered if the formation or enlargement of the aneurysmal dilatation has been confirmed. Since there are several proposed surgical strategies for IAD, it is important to select an appropriate strategy on a case-by-case basis. If the risk of infarction due to vessel occlusion is high, combined bypass surgery should be considered..
20. Nobuyuki Sakai, Hirotoshi Imamura, Chiaki Sakai, Koichi Arimura, Hidemitsu Adachi, Shoichi Tani, Takayuki Funatsu, Mikiya Beppu, Noriyoshi Takebe, Keita Suzuki, Tomohiro Okuda, Yuichi Matsui, Yasunori Yoshida, Shuhei Kawabata, Basic technique of endovascular treatment of intracranial aneurysms, Japanese Journal of Neurosurgery, 10.7887/jcns.24.833, 24, 12, 833-839, 2015.12, The basic technique for endovascular treatment of intracranial aneurysm is a simple method requiring a single microcatheter and a long enough detachable coil for the coil embolization. Key factors for technical success are stability of the microcatheter based on the direction of the parent artery in relation to the aneurysm. Additionaly, the appropriate selection of framing, filling and finishing coils is another important factor. If adjunctive techniques are required, balloon and or stent assisted methods are available. But in most instances, the simple method will suffice and is therefore the most important and basic strategy for endovascular treatment of intracranial aneurysms..
21. Noriko Makihara, Koichi Arimura, Tetsuro Ago, Masaki Tachibana, ataru nishimura, Kuniyuki Nakamura, ryu matsuo, Yoshinobu Wakisaka, Junya Kuroda, Hiroshi Sugimori, Masahiro Kamouchi, Takanari Kitazono, Involvement of platelet-derived growth factor receptor β in fibrosis through extracellular matrix protein production after ischemic stroke, Experimental Neurology, 10.1016/j.expneurol.2014.12.007, 264, 127-134, 2015.02, Fibrosis is concomitant with repair processes following injuries in the central nervous system (CNS). Pericytes are considered as an origin of fibrosis-forming cells in the CNS. Here, we examined whether platelet-derived growth factor receptor β (PDGFRβ), a well-known indispensable molecule for migration, proliferation, and survival of pericytes, was involved in the production of extracellular matrix proteins, fibronectin and collagen type I, which is crucial for fibrosis after ischemic stroke. Immunohistochemistry demonstrated induction of PDGFRβ expression in vascular cells of peri-infarct areas at 3-7. days in a mouse stroke model. The PDGFRβ-expressing cells extended from peri-infarct areas toward the ischemic core after day 7 while expressing fibronectin and collagen type I in the infarct areas. In contrast, desmin and α-smooth muscle actin, markers of pericytes, were only expressed in vascular cells. In PDGFRβ heterozygous knockout mice, the expression of fibronectin and collagen type I was attenuated at both mRNA and protein levels with an enlargement of the infarct volume after ischemic stroke compared with that in wild-type littermates. In cultured brain pericytes, the expression of PDGF-B, PDGFRβ, fibronectin, and collagen type I, but not desmin, was significantly increased by serum depletion (SD). The SD-induced upregulation of fibronectin and collagen type I was suppressed by SU11652, an inhibitor of PDGFRβ, while PDGF-B further increased the SD-induced upregulation. In conclusion, the expression level of PDGFRβ may be a crucial determinant of fibrosis after ischemic stroke. Moreover, PDGFRβ signaling participates in the production of fibronectin and collagen type I after ischemic stroke..
22. Kuniyuki Nakamura, Masahiro Kamouchi, Koichi Arimura, ataru nishimura, Junya Kuroda, Koji Ishitsuka, Himiko Tokami, Hiroshi Sugimori, Tetsuro Ago, Takanari Kitazono, Extracellular acidification activates cAMP responsive element binding protein via Na+/H+ exchanger isoform 1-mediated Ca 2+ oscillation in central nervous system pericytes, Arteriosclerosis, thrombosis, and vascular biology, 10.1161/ATVBAHA.112.254946, 32, 11, 2670-2677, 2012.11, Objective-We have previously shown that Na+/H+ exchanger isoform 1 (NHE1) plays an important role in Ca2+ signaling and cell proliferation in human central nervous system (CNS) pericytes. The aims of the present study were to elucidate how NHE1-induced Ca2+ signaling during acidosis is transformed into cellular responses in CNS pericytes. Methods and Results-Human CNS pericytes were cultured, and the activation of cAMP responsive element-binding protein (CREB) was evaluated by Western blotting analysis, immunofluorescence, and luciferase assays. In human CNS pericytes, low extracellular Na+ or low pH generated Ca 2+ oscillation and subsequently phosphorylated Ca2+/ calmodulin-dependent kinase II (CaMKII) and CREB in a time-dependent manner. Focal cerebral ischemia was applied using photothrombotic distal middle cerebral artery occlusion in mice, and the phosphorylation of CREB and the production of interleukin-6 were observed in pericytes migrating into the peri-infarct penumbra during the early phase after ischemic insult. Conclusion-Our results indicate that extracellular acidosis induces Ca2+ oscillation via NHE1, leading to Ca2+/CaMKII-dependent CREB activation in human CNS pericytes. Acidosis may upregulate a variety of proteins, such as interleukin-6, through the NHE1-Ca2+/CaMKII-CREB pathway in brain pericytes and may thus modulate brain ischemic insult..
23. Koji Ishitsuka, Tetsuro Ago, Koichi Arimura, Kuniyuki Nakamura, Himiko Tokami, Noriko Makihara, Junya Kuroda, Masahiro Kamouchi, Takanari Kitazono, Neurotrophin production in brain pericytes during hypoxia
A role of pericytes for neuroprotection, Microvascular Research, 10.1016/j.mvr.2012.02.009, 83, 3, 352-359, 2012.05, Neurotrophins are crucial regulators of neuronal survival and death. Evidence suggests that cells comprising the neurovascular unit (NVU) cooperatively mediate neuronal development, survival and regeneration. The aim of this study was to test whether cerebrovascular cells, endothelial cells and pericytes, produce neurotrophins and play neuroprotective roles during hypoxic insults. We examined the expression of neurotrophins and their receptors in cultured human cerebral microvascular endothelial cells and pericytes, astrocytes and the rat neuronal cell line PC12. Differentiated PC12 cells expressed TrkA, the NGF receptor, which was significantly upregulated by hypoxia at 1% O 2 and regulated neuronal survival. Both pericytes and astrocytes expressed three neurotrophins, i.e. NGF, BDNF and NT-3, while TrkB and TrkC, specific receptors for BDNF and NT-3, were expressed in astrocytes, but not pericytes. In response to hypoxia, among the neurotrophins expressed in pericytes and astrocytes only NT-3 expression was significantly upregulated in pericytes. Treatment of astrocytes with NT-3 significantly activated Erk1/2 and increased the expression of NGF both at mRNA and protein levels. The MEK1 inhibitor U0126 or siRNA-mediated knockdown of TrkC abolished the NT-3-induced upregulation of NGF in astrocytes. Taken together, cerebral microvascular pericytes and astrocytes are potent producers of neurotrophins in the NVU. In response to hypoxia, pericytes increase NT-3 production, which induces astrocytes to increase NGF production through the TrkC-Erk1/2 pathway. The interplay between pericytes and astrocytes through neurotrophins in the NVU may play an important role in neuronal survival under hypoxic conditions..
24. Arimura K, Ago T, Kamouchi M, Nakamura K, Ishitsuka K, Kuroda J, Sugimori H, Ooboshi H, Sasaki T, Kitazono T., PDGF Receptor beta Signaling in Pericytes Following Ischemic Brain Injury, CURRENT NEUROVASCULAR RESEARCH, 9, 1, 1-9, 2012.02.
25. Koichi Arimura, Tetsuro Ago, Masahiro Kamouchi, Kuniyuki Nakamura, Koji Ishitsuka, Junya Kuroda, Hiroshi Sugimori, Hiroaki Ooboshi, Tomio Sasaki, Takanari Kitazono, PDGF receptor β signaling in pericytes following ischemic brain injury, Current Neurovascular Research, 10.2174/156720212799297100, 9, 1, 1-9, 2012.01, Platelet derived growth factor (PDGF)-B plays a neuroprotective role in brain damages, including ischemic stroke. It has been suggested recently that PDGF receptor β (PDGFRβ) expressed in brain pericytes as well as in neurons and astrocytes may mediate the neuroprotective role of PDGF-B. The aims of this study were to elucidate the roles of PDGFRβ signaling in brain pericytes after ischemic stroke. In a rat middle cerebral artery occlusion (MCAO) model, PDGFRβ expression was induced specifically in the pericytes in peri-infarct areas and its level was gradually increased. PDGF-B induced marked phosphorylation of Akt in cultured brain pericytes. Consistently, PDGF-B was upregulated in endothelial cells in per-infarct areas and Akt was strongly phosphorylated in the PDGFRβ-expressing pericytes in periinfarct areas after MCAO. In the cultured pericytes, PDGF-B induced cell growth and anti-apoptotic responses through Akt. Furthermore, PDGF-B significantly increased the expression of nerve growth factor (NGF) and neurotrophin-3 (NT-3) through Akt in the pericytes. Thus, the PDGFRβ-Akt signaling in brain pericytes may play various important roles leading to neuroprotection after ischemic stroke..
26. Yasushi Miyagi, Yoshihiro Natori, Satoshi Suzuki, Toru Iwaki, Takato Morioka, Koichi Arimura, Yoshihisa Maeda, Tadahisa Shono, Koichiro Matsukado, Tomio Sasaki, Purely cystic form of choroid plexus papilloma with acute hydrocephalus in an infant
Case report, Journal of Neurosurgery, 105 PEDIATRICS, SUPPL. 6, 480-484, 2006.12, Infants with acute hydrocephalus often present with nonspecific neurological signs, and cystic choroid plexus papilloma (CPP) is a very rare cause of acute obstructive hydrocephalus. The authors present the case of a 1-year-old girl who became irritable, started vomiting, and became comatose within a day. Magnetic resonance (MR) imaging revealed a cystic lesion in the third ventricle as well as hydrocephalus. Although the aqueduct appeared to be patent, phase-contrast MR imaging showed no pulsatile flow of cerebrospinal fluid in the ventricles. An emergent endoscopic third ventriculostomy was performed. Endoscopic examination revealed a highly mobile cyst attached by a pedicle to the choroid plexus adjacent to the Monro foramen in the lateral ventricle. The cyst was totally excised during the endoscopic procedure and was subsequently diagnosed as a CPP on the basis of histopathological findings. Purely cystic CPP is a very rare pathological entity; however, when it does occur, it can cause obstructive hydrocephalus which, without rapid diagnosis and surgical intervention, could lead to sudden death..
27. Koichi Arimura, Hiroyuki Murai, Hitoshi Kikuchi, Hiroshi Shigeto, Takayuki Taniwaki, Hirokazu Furuya, Jun-Ichi Kira, Relapsing Wernicke's encephalopathy after gastrectomy, Nihon Naika Gakkai zasshi. The Journal of the Japanese Society of Internal Medicine, 10.2169/naika.94.1606, 94, 8, 1606-1608, 2005.01.