A Bioengineering Approach to Create Immunorejection Free Human Pancreatic Islets

描述(申请人提供)：据估计，到2015年，美国将有十分之一的人口患有糖尿病。胰岛移植在治疗糖尿病方面具有巨大的潜力，但首先必须克服与胰岛存活、功能和免疫排斥相关的问题。将生物工程和胰岛生物学结合起来，在克服这些挑战方面具有巨大的潜力。我们已经报道，无论是在体外还是在体内，人骨髓(BM)都能显著改善人的胰岛功能和存活，但这种有益作用的机制在很大程度上尚不清楚。我们有初步数据表明，BM通过启动血运重建和刺激人胰岛再生，促进了人胰岛在体外的存活和功能。为了解决人类胰岛的免疫排斥问题，我们提出了一种包裹人胰岛/骨髓共培养的生物工程方法，并将在体内使用植入有功能的人类免疫系统的小鼠(人源化小鼠)进行测试。我们推测，共包裹的BM+胰岛创造了一个良好的微环境，通过这种微环境，BM旁分泌活性促进了人胰岛的血运重建，增强了细胞的自我再生，并防止了免疫排斥。我们将研究BM如何在人源化小鼠中维持人类胰岛功能/生存和防止人类免疫排斥的机制，以及使用含有选定细胞因子的纳米颗粒局部释放到胰岛的好处。为了了解人类骨髓如何在被包裹的微环境中促进人类胰岛的生存和功能，我们将(1)评估在被包裹的胰岛和骨髓组织的3D结构中发生的血运重建和细胞再生；(2)评估微囊化胰岛加BM克服人类免疫排斥反应和恢复糖尿病人源化小鼠血糖稳态的能力，并确定半透性水凝胶胶囊中携带细胞因子的纳米颗粒是否通过招募祖细胞来促进微囊化胰岛的支持；(3)通过确定BM旁分泌血小板衍生生长因子(PDGF或其他因子)和MIR-RNA24-2调控PDGF信号通路对胰岛存活和功能的影响，确定BM在微囊化环境中增强人胰岛存活和功能的机制。我们的长期目标是确定囊化胰岛加骨髓细胞在体内维持胰岛功能的机制(S)，并在没有全身性免疫抑制的情况下防止胰岛排斥反应，以便移植到临床。

DESCRIPTION (provided by applicant): By 2015, it is estimated that one tenth of the U.S. population will suffer from diabetes. Islet transplantation has great potential for the treatment o diabetes, but must first overcome issues associated with islet survival, function and immunorejection. Combining bioengineering and islet biology has great potential for overcoming these challenges. We have reported that human bone marrow (BM), either in vitro or in vivo, significantly improves human islet function and survival, but the mechanisms underlying this beneficial effect are largely unknown. We have preliminary data, that BM facilitates human islet survival and function in vitro by initiating revascularization and stimulating human islet regeneration. To address immunorejection of human islets, we propose a bioengineering approach of encapsulation of human islet/BM co- cultures and we will test this in vivo using mice engrafted with a functional human immune system (humanized mice). We hypothesize that co-encapsulated BM plus islets creates a favorable microenvironment via which BM paracrine activity facilitates revascularization of human islets, enhances ¿ cell self regeneration and prevents immunorejection. We will investigate mechanisms of how BM sustains human islet function/survival and prevents human immunorejection in humanized mice and the benefits of using nanoparticles with selected cytokines incorporated for local release to the islets. To understand how human BM facilities human islet survival and function within an encapsulated microenvironment, we will (1) evaluate revascularization and ¿-cell regeneration that occurs within a 3D construction of the encapsulated islet and BM tissues; (2) evaluate the ability of encapsulated islets plus BM to overcome human immunorejection and restore glucose homeostasis in diabetic humanized mice, and determine whether nanoparticles carrying cytokines in a semi-permeable hydrogel capsule facilitate support of encapsulated functional islets by recruiting progenitor cells, and (3) identify the mechanisms by which BM enhances human islet survival and function in an encapsulated microenvironment by identifying the effect of BM paracrine Platelet-derived growth factor (PDGF or other factors) and Mir-RNA 24-2 to modulate PDGF signaling pathways on islet survival and function. Our long term goal is to identify the mechanism(s) by which encapsulated islets plus BM cells sustain islet function in vivo and prevent islet rejection in the absence of generalized immunosuppression for translation to the clinic.