The in vivo performance of polyvinyl alcohol macro-encapsulated islets

Qi, Zhi; Shen, Yanna; Yanai, Goichi; Yang, Kang; Shirouzu, Yasumasa; Hiura, Akihito; Sumi, Shoichiro

doi:10.1016/j.biomaterials.2010.01.088

Cited by 32 publications

(29 citation statements)

References 16 publications

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“…In contrast, micro-encapsulated islets are one or a few islets enclosed in semi-permeable membranes, which can provide a surface for diffusion, therefore maintaining the functions of islets inside. However, they are irretrievable after transplantation (38) . When islets are transplanted, 50% of the tissue may be lost in the first few days; this is thought to be due to hypoxic death before vascularization develops (36) .…”

Section: Discussionmentioning

confidence: 99%

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Islet transplantation in rodents: do encapsulated islets really work?

Souza

Chaib

Lacerda

et al. 2011

Arq. Gastroenterol.

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-Context -Diabetes mellitus type I affects around 240 million people in the world and only in the USA 7.8% of the population.It has been estimated that the costs of its complications account for 5% to 10% of the total healthcare spending around the world. According to World Health Organization, 300 million people are expected to develop diabetes mellitus by the year 2025. The pancreatic islet transplantation is expected to be less invasive than a pancreas transplant, which is currently the most commonly used approach. Objectives -To compare the encapsulated and free islet transplantation in rodents looking at sites of islet implantation, number of injected islets, viability and immunosuppression. Methods -A literature search was conducted using MEDLINE/PUBMED and SCIELO with terms about islet transplantation in the rodent from 2000 to 2010. We found 2,636 articles but only 56 articles from 2000 to 2010 were selected. Results -In these 56 articles used, 34% were encapsulated and 66% were nonencapsulated islets. Analyzing both types of islets transplantation, the majority of the encapsulated islets were implanted into the peritoneal cavity and the nonencapsulated islets into the liver, through the portal vein. In addition, the great advantage of the peritoneal cavity as the site of islet transplantation is its blood supply. Both vascular endothelial cells and vascular endothelial growth factor were used to stimulate angiogenesis of the islet grafts, increasing the vascularization rapidly after implantation. It also has been proven that there is influence of the capsules, since the larger the capsule more chances there are of central necrosis. In some articles, the use of immunosuppression demonstrated to increase the life expectancy of the graft. Conclusion -While significant progress has been made in the islets transplantation field, many obstacles remain to be overcome. Microencapsulation provides a means to transplant islets without immunosuppressive agents and may enable the performance of xenotransplantation. The use of alternative donor sources, fewer islets per capsule and the appropriate deployment location, such as the peritoneal cavity, may give a future perspective to the application of immunoprotective capsules and viability in clinical practice. A variety of strategies, such as genetic engineering, co-encapsulation, improvement in oxygen supply or the establishment of hypoxia resistance will also improve the islet transplantation performance. It remains to be determined which combination of strategies with encapsulation can fulfill the promise of establishing a simple and safe transplantation as a cure for diabetes.

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Section: Discussionmentioning

confidence: 99%

“…Qi et al (38) have suggested the use of polyvinyl alcohol macro-encapsulated islets for long-term preservation (7 days) is better, because they allow overcoming the obstacles of insufficient donors and the side effects of immunosuppressive drugs.…”

Section: Discussionmentioning

confidence: 99%

Islet transplantation in rodents: do encapsulated islets really work?

Souza

Chaib

Lacerda

et al. 2011

Arq. Gastroenterol.

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“…Meanwhile, long-term preservation further shows following advantages for research and clinical islet transplantation: (1) Islets isolated at different time can be accumulated to obtain a sufficient number for transplantation. (2) Isolated islets can be transported to other institutions worldwide [5].…”

Section: Introductionmentioning

confidence: 99%

Optimal method for short-term or long-term islet preservation: comparison of islet culture, cold preservation and cryopreservation

et al. 2014

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Islet preservation plays an important role for the success of islet transplantation. To determine the optimal method for islet preservation, we compared the outcomes of islet culture, cold preservation, and cryopreservation in this study. Isolated rat islets were divided into three groups: 37 °C group (conventional culture at 37 °C in RPMI-1640 medium), 4 °C group (cold preservation at 4 °C in University of Wisconsin (UW) solution), and -80 °C group (cryopreservation at -80 °C with dimethyl sulfoxide (DMSO)). Recovery rate, Calcein-AM/PI double staining, insulin release, mRNA level of hypoxia-inducible factor-1α (HIF-1α), and protein level of Bax in islets were examined after short-term (1 day) or long-term (7 days) preservation. After either short-term or long-term preservation, 4 °C group showed higher recovery rate of the islets number, lower percentage of PI positive area, better insulin release ability, and lower expression levels of HIF-1α and Bax in comparison to the 37 or -80 °C group. Meanwhile, islets in 37 °C group showed better function, and down-regulation of HIF-1α and Bax than those in -80 °C group on day 1; however, worse function of islets, up-regulated HIF-1α and Bax in 37 °C group were observed in comparison to -80 °C group on day 7. These results suggest that cold preservation at 4 °C in UW solution is the optimal method in comparison to the conventional culture at 37 °C or cryopreservation at -80 °C for short-term or long-term islet preservation. Furthermore, the potential mechanism may relate to, at least in part, apoptosis induced by the HIF-1α.

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“…With the encapsulation of islets in Euro-Collins solution by freezing/thawing technique, the PVA+EC group demonstrated normal effective insulin secretion and lower glucose levels for a much longer time [27]. It was found that the sheet-type PVA macroscopic devices were useful for islet long-term cryopreservation [28]. With the advantages of an easy preparation method and relatively convenient retrieval when the transplants fail to function, macroscopic devices have attracted great attention and have been successfully applied in small animal models, large animal models,and even humans [29][30][31][32].…”

Section: Concept Of Cell Encapsulationmentioning

confidence: 99%

Microscale Cell Encapsulation Materials and Fabrication Techniques for Type 1 Diabetes

2016

Microscale Technologies for Cell Engineering

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The in vivo performance of polyvinyl alcohol macro-encapsulated islets

Cited by 32 publications

References 16 publications

Islet transplantation in rodents: do encapsulated islets really work?

Islet transplantation in rodents: do encapsulated islets really work?

Optimal method for short-term or long-term islet preservation: comparison of islet culture, cold preservation and cryopreservation

Microscale Cell Encapsulation Materials and Fabrication Techniques for Type 1 Diabetes

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