Adipose Stromal Cells and Vasculogenesis: Tissue Perfusion and Islet Survival

描述(由申请人提供)： 脂肪组织中多能细胞的描述导致了这样的概念，即脂肪组织可能提供一种新的自体细胞来源，具有显著的组织修饰潜力。这样的脂肪基质细胞(ASCs)可以在常规的皮下脂肪组织抽吸后获得大量的108到109个细胞。这种现成的可获得性反过来表明，它们可能提供一种特别可行和有吸引力的自体细胞治疗形式。我们实验室的工作得到了我们先前的优点回顾以及其他人的支持，清楚地表明ASCs在几种情况下可以通过分泌血管生成和抗凋亡因子来增加组织灌注量和限制缺血组织损伤。最近，我们还发现ASCs在体外能够稳定内皮细胞网络，并与内皮细胞(EC)强效协同参与体内新血管的形成。此外，这一观察使我们假设ASC和EC之间的协同作用将为植入物或局部缺血的组织血管化提供一种实用的方法。我们最近的研究发现，培养中的ASCs可以促进胰岛的持续分泌功能，并且当ASCs与内皮细胞和胰岛共同移植时，ASCs组装血管网络，这促使我们进一步评估这些细胞组装血管和调节胰岛反应的机制。因此，这一建议的总体假设是，ASCs是唯一可获得和可扩展的多能细胞，具有沿着形成血管壁细胞的途径分化的能力，并且可以促进体内血管生成和移植胰岛背景下的细胞存活。为了检验这一假说，将追求的具体目标是1。(1)评价血管内皮细胞在体外和体内调控ASC介导的血管网络形成的机制、动力学和关键因素；评估ASC或ASC亚群在体外和体内通过直接旁分泌支持胰岛功能的能力；以及通过ASC和EC在体内组装嵌合的人类血管网络来进一步保存胰岛功能；以及确定糖尿病和衰老对人ASCs参与体内嵌合血管生成的能力的影响，以及对主要血管生成控制因子HIF-1a和HIF-1bin ASCs的信号功能的影响。这项研究将有助于确定ASC和EC联合移植在多大程度上可以帮助组织存活；通过使用胰岛移植作为模型，将允许评估ASCs和它们可以帮助形成的血管网络是否可以显著增强胰岛移植。此外，这项研究将阐明从糖尿病患者获得的自体ASC通过旁分泌效应或血管形成促进组织存活的潜力；并确定糖尿病患者ASC功能损害的关键分子机制。这些功能的显著损害将突出涉及靶向修饰自体ASC或同种异体ASC的方法的必要性。 公共卫生相关性： 我们的研究将深入了解如何利用脂肪组织中的干细胞来帮助创建血管结构，以帮助为需要的组织，特别是移植的胰岛提供血液供应。由于我们正在使用适合人类使用的细胞制备设备/方法，因此这项研究中提出的见解将直接翻译给退伍军人。具体地说，我们预计我们正在研究的方法将适用于因血流不畅而出现问题的退伍军人；例如伤口愈合不良的退伍军人；以及可能从胰岛移植中受益的退伍军人，以治疗或实际治愈他们的糖尿病。这项研究的发现将为胰岛与能够组装血管结构的细胞一起移植的优化方法指明方向；还将确定是否可以使用来自所有患者的细胞，或者是否必须探索来自更年轻或更健康患者的细胞，以及为什么。治疗糖尿病和糖尿病血管疾病的成功工作将显著提高有效性，并可能确实降低退伍军人管理系统的长期医疗成本。

DESCRIPTION (provided by applicant): The description of pluripotent cells in adipose tissue has led to the concept that adipose tissue may provide a novel autologous source of cells with significant potential for tissue modification. Such adipose stromal cells (ASCs) can be obtained in large quantities, in the range of 108 to 109 cells, following routine liposuction of subcutaneous adipose tissue. This ready accessibility in turn has suggested the notion that they might provide for a particularly feasible and attractive form of autologous cell therapy. Work in our laboratory supported by our prior Merit Review, as well as that of others, has clearly demonstrated that ASCs can increase tissue perfusion and limit ischemic tissue damage in several circumstances, by secretion of angiogenic and anti-apoptotic factors. Recently, we have also found that ASCs are capable of stabilizing endothelial networks in vitro as well as robustly synergizing with endothelial cells (EC) to participate in the in vivo formation of new vessels. Additionally, this observation led us to hypothesize that the synergy between ASC and EC would provide a practical approach to tissue vascularization for implants or regional ischemia. Our recent findings that ASCs in culture can promote sustained secretory function of pancreatic islets, and that ASCs assemble vascular networks when co-implanted with both endothelial cells and islets, has prompted us to further evaluate the mechanisms by which these cells assemble vessels and modulate islet responses. The overall hypothesis of this proposal is thus that ASCs are uniquely accessible and expandible pluripotent cells that have the capacity to differentiate along pathways giving rise to vascular mural cells, and which can facilitate in vivo vasculogenesis and cell survival in the context of implanted islets. The specific aims that will be pursued in order to test this hypothesis are 1.) Evaluate the mechanisms, dynamics, and key factors responsible for governing ASC-mediated vascular network formation by ECs in vitro and in vivo; 2.) Evaluate the capacity of ASC or ASC subpopulations to support pancreatic islet function in vitro and in vivo by direct paracrine support; and to further preserve islet function by assembly of a chimeric human vascular network by ASC and EC in vivo; and 3.) Determine the effect of diabetes and aging on the competency of human ASCs to participate in chimeric vasculogenesis in vivo, and on the signalling function of the master angiogenic control factors, HIF-1a and HIF-1bin ASCs. This study will help to determine the extent to which ASC and EC co-transplantation can assist with tissue survival; and by using islet transplantation as a model, will permit an assessment of whether islet transplantation can be significantly augmented by ASCs and vascular networks which they can help to form. In addition, this study will clarify the potential of autologous ASC obtained from patients with diabetes to contribute to tissue survival via either paracrine effects or vascularization; and identify key molecular mechanisms underlying functional impairment of ASC in diabetes. Marked impairment in these functions would highlight the need for approaches involving either targeted modification of autologous ASC, or allogeneic ASC. PUBLIC HEALTH RELEVANCE: Our study will provide insight into how to use the stem cells located in fat tissue to assist in creating blood vessel structures to help provide blood supply to tissues that require it, and in particular to islets that are transplanted. Since we are working with cell preparation devices / methods that are appropriate for human use, the insights developed in this study will be directly translatable to Veterans. Specifically, we anticipate that the approaches we are studying will apply to Veterans that have problems due to poor blood flow; such as poor wound healing; and to diabetic Veterans who may be able to benefit from islet transplantation to treat or actually cure their diabetes. The findings from this study will point the way to optimized methods for transplanting islets along with cells that can assemble vascular structures; and will also determine whether cells from all patients can be used, or whether cells from younger or healthier patients must be explored, and why. Successful work to treat diabetes and diabetic vascular disease will markedly improve the effectiveness, and may indeed decrease longterm costs of healthcare in the Veterans Administration system.