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Kozue Yoshida, Fumiyasu Ono, Takehiro Chouno, Shota Nakada, Yasuhiro Ikegami, Nana Shirakigawa, Yusuke Sakai, Hiroyuki Ijima, Creation of a novel lipid-trehalose derivative showing positive interaction with the cell membrane and verification of its cytoprotective effect during cryopreservation., Journal of bioscience and bioengineering, 10.1016/j.jbiosc.2021.03.010, 132, 1, 71-80, 2021.07, Cryopreservation is important for enabling long-term cell preservation. However, physical damage due to ice crystal formation and membrane permeation by dimethyl sulfoxide (DMSO) severely affects cryopreserved cell viability. To ensure cell survival and functional maintenance after cryopreservation, it is important to protect the cell membrane, the most vulnerable cell component, from freeze-thaw damage. This study aimed to create a glycolipid derivative having a positive interaction with the cell membrane and cytoprotective effects. As a result, we synthesized a novel trehalose derivative, oleyl-trehalose (Oleyl-Treh), composed of trehalose and oleyl groups. Its use led to increased viable cell counts when used with DMSO in a non-cytotoxic concentration range (1.6 nM-16 μM). Oleyl-Treh significantly improved viability and liver-specific functions of hepatocytes after cryopreservation, including albumin secretion, ethoxyresorufin-O-deethylase activity (an indicator of cytochrome P450 family 1 subfamily A member 1 activity), and ammonia metabolism. Oleyl-Treh could localize trehalose to the cell membrane; furthermore, the oleyl group affected cell membrane fluidity and exerted cryoprotective effects. This novel cryoprotective agent, which shows a positive interaction with the cell membrane, provides a unique approach toward cell protection during cryopreservation.. |
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Hiroki Sakamoto, Nana Shirakigawa, Ronald Perocho Bual, Yukako Fukuda, Shunsuke Nakamura, Tatsunori Miyata, Takanobu Yamao, Yo ichi Yamashita, Hideo Baba, Hiroyuki Ijima, A novel evaluation system for whole-organ-engineered liver graft by ex vivo application to a highly reproducible hepatic failure rat model, Journal of Artificial Organs, 10.1007/s10047-019-01106-6, 22, 3, 222-229, 2019.09, © 2019, The Japanese Society for Artificial Organs. In recent years, studies on liver graft construction using the decellularized liver as a template for transplantation therapy have attracted much attention. However, the therapeutic effect of constructed liver grafts in hepatic failure has not been evaluated. Therefore, we aimed to develop a novel evaluation system demonstrating the curative effect of a constructed liver graft in animals with hepatic failure. First, we developed a highly reproducible rat model of hepatic failure by combining 80% partial hepatectomy with warm ischemia. In this model, severity could be controlled by the warm ischemic period. We also constructed a liver graft by recellularization of decellularized liver, and confirmed the ammonia metabolic function in the graft in vitro as one of the most important functions for recovery from hepatic failure. The graft was then applied to our developed hepatic failure rat model using a blood extracorporeal circulation system. In this application, the graft metabolized the ammonia in the blood of animals with hepatic failure and was thus suggested to be effective for the treatment of hepatic failure. In summary, a novel evaluation system for whole-organ-engineered liver graft as a preliminary stage of transplantation was developed. This system was expected to provide much information about the curative effect of a constructed liver graft.. |
| 3. |
Nana Shirakigawa, Tadamitsu IDEGUCHI, Kazuyuki ICHIKAWA, Takahisa IZUMI, Michiko HIGASHI, Shizunari YAMAMOTO, Hiroyuki Ijima, Quantitative Analysis of Vascular Structure in Decellularized Liver Using 3D Computed Tomography, Advanced Biomedical Engineering, 10.14326/abe.4.179, 4, 179-185, 2015.08. |
| 4. |
Nana Shirakigawa, Takayuki Takei, Hiroyuki Ijima, Base structure consisting of an endothelialized vascular-tree network and hepatocytes for whole liver engineering, Journal of Bioscience and Bioengineering, 10.1016/j.jbiosc.2013.05.020, 116, 6, 740-745, 2013.12, Reconstructed liver has been desired as a liver substitute for transplantation. However, reconstruction of a whole liver has not been achieved because construction of a vascular network at an organ scale is very difficult. We focused on decellularized liver (DC-liver) as an artificial scaffold for the construction of a hierarchical vascular network. In this study, we obtained DC-liver and the tubular network structure in which both portal vein and hepatic vein systems remained intact. Furthermore, endothelialization of the tubular structure in DC-liver was achieved, which prevented blood leakage from the tubular structure. In addition, hepatocytes suspended in a collagen sol were injected from the surroundings using a syringe as a suitable procedure for liver cell inoculation. In summary, we developed a base structure consisting of an endothelialized vascular-tree network and hepatocytes for whole liver engineering.. |
