Köllmer Melanie, Appel Alyssa A, Somo Sami I, Brey Eric M
1 Department of Biomedical Engineering, Illinois Institute of Technology , Chicago, Illinois.
2 Research Service, Hines Veterans Administration Hospital , Hines, Illinois.
Tissue Eng Part B Rev. 2016 Feb;22(1):34-46. doi: 10.1089/ten.TEB.2015.0140. Epub 2015 Oct 15.
Human trials have demonstrated the feasibility of alginate-encapsulated islet cells for the treatment of type 1 diabetes. Encapsulated islets can be protected from the host's immune system and remain viable and functional following transplantation. However, the long-term success of these therapies requires that alginate microcapsules maintain their immunoprotective capacity and stability in vivo for sustained periods. In part, as a consequence of different encapsulation strategies, islet encapsulation studies have produced inconsistent results in regard to graft functioning time, stability, and overall metabolic benefits. Alginate composition (proportion of M- and G-blocks), alginate purity, the cross-linking ions (calcium or barium), and the presence or absence of additional polymer coating layers influence the success of cell encapsulation. This review summarizes the outcomes of long-term studies of alginate-encapsulated islet transplants in animals and humans and provides a critical discussion of the graft failure mechanisms, including issues with graft biocompatibility, transplantation site, and integrity of the encapsulated islet grafts. Strategies to improve the mechanical stability of alginate capsules and methods for monitoring graft survival and function in vivo are presented.
人体试验已证明藻酸盐包封的胰岛细胞用于治疗1型糖尿病的可行性。包封的胰岛可免受宿主免疫系统的攻击，并在移植后保持存活和功能。然而，这些疗法的长期成功需要藻酸盐微胶囊在体内长期维持其免疫保护能力和稳定性。部分由于不同的包封策略，胰岛包封研究在移植物功能时间、稳定性和总体代谢益处方面产生了不一致的结果。藻酸盐组成（M-和G-块的比例）、藻酸盐纯度、交联离子（钙或钡）以及是否存在额外的聚合物涂层会影响细胞包封的成功。本综述总结了藻酸盐包封的胰岛移植在动物和人体中的长期研究结果，并对移植物失败机制进行了批判性讨论，包括移植物生物相容性、移植部位和包封的胰岛移植物完整性等问题。还介绍了提高藻酸盐胶囊机械稳定性的策略以及体内监测移植物存活和功能的方法。
