Generation of Synthetic Human Islet Microorgans

描述（由申请人提供）：本提案的总体目标是对含胰腺β细胞的植入物进行生物工程改造，用于治疗糖尿病。人类胰岛成功移植的主要障碍是其存活率降低，这是由胰岛收集期间的损伤和移植后缺乏足够的血管重建引起的。已经开发了支持人胰岛在SCID（严重联合免疫缺陷）小鼠体内存活和功能的条件。我们先前建立了用于形成源自人内皮细胞（EC）的人微血管床的条件，所述人内皮细胞在胶原/纤连蛋白凝胶中浇铸，然后植入SCID小鼠。将胰岛与EC一起铸造，有效地使胰岛再血管化。事实上，我们的试验数据表明，这些人胰岛EC微生物将人胰岛素分泌到小鼠的外周血中至少4个月的时间，并在葡萄糖耐量试验中表现出对葡萄糖的响应性。本项目的第一个目的是表征这种微生物的结构/功能特性，包括微血管结构和微血管随时间的稳定性。由于人胰岛素的分泌随着时间的推移而改善，我们将测试β细胞的增殖，并检查这些微生物是否可以治愈小鼠的化学诱导的糖尿病。在第二个目标中，我们将测试血管化胰岛暴露于同种异体反应性人类细胞时的功能。Bcl-2过表达使人EC抵抗同种异体排斥反应。我们推测，胰岛血管化与Bcl-2转导EC不会受到同种异体人淋巴细胞。对于临床应用，有必要开发更大的微器官植入物，并优化β细胞功能和血管重建的存活条件。第三个目标是利用各种合成分子支架来增加尺寸和功能。最后，微球的使用将被优化用于递送将促进β细胞存活和功能的因子。该模型将对改善人类胰岛移植后的存活率具有重要意义。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to bioengineer pancreatic beta cell-containing implants for treatment of diabetes. A major obstacle to successful transplantation of human islets is their decreased survival caused by damage during their collection and lack of adequate revascularization post-transplant. Conditions have been developed that support the survival and function of human islets in vivo in SCID (severe combined immunodeficient) mice. We previously established conditions for formation of a human microvascular bed derived from human endothelial cells (EC) that are cast in collagen/fibronectin gels and then implanted into SCID mice. Casting the islets together with EC effectively revascularize the islets. Indeed, our pilot data indicate that these human islet-EC microorganisms secrete human insulin into the peripheral blood of mice for periods of at least 4 months and demonstrate responsiveness to glucose in glucose tolerance tests. The first aim of this project is to characterize the structure/function properties of this microorganism, including the microvessel structure and the stability of the microvessels with time. Since the secretion of human insulin improves over time, we will test for proliferation of beta cells and also examine whether these microorganism can cure chemically-induced diabetes in mice. In the second aim, we will test the function of the revascularized islets when they are exposed to alloreactive human cells. Bcl-2 overexpression renders human EC resistant to allorejection. We hypothesize that the islets revascularized with Bcl-2-transduced EC will not be affected by the allogeneic human lymphocytes. For clinical use it will be necessary to develop a larger microorgan implant and optimize conditions for both survivals of beta cell function and revascularization. The third aim will utilize various synthetic molecular scaffolds to increase the size and function. Finally, the use of microspheres will be optimized for the delivery of factors that will promote beta cell survival and function. This model will have significant implications for improving post-transplant survival of human islets.