Adipose Stromal Cells and Vasculogenesis: Tissue Perfusion and Islet Survival

描述（由申请人提供）： 对脂肪组织中多能细胞的描述导致了这样的概念，即脂肪组织可以提供具有显著组织修饰潜力的新型自体细胞来源。这种脂肪基质细胞（ASC）可以在皮下脂肪组织的常规吸脂后大量获得，在IO 8至IO 9个细胞的范围内。这种现成的可及性反过来又提出了这样的概念，即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之前的Merit Review以及其他人的支持，已经清楚地表明，ASC可以通过分泌血管生成因子和抗凋亡因子来增加组织灌注并在几种情况下限制缺血性组织损伤。最近，我们还发现ASCs能够在体外稳定内皮网络，并与内皮细胞（EC）协同参与体内新血管的形成。此外，这一观察结果使我们假设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植入时，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，该提议的总体假设是ASC是独特的可接近和可扩增的多能细胞，其具有沿着产生血管壁细胞的途径分化的能力，并且其可以在植入的胰岛的情况下促进体内血管发生和细胞存活。为了检验这一假设，将追求的具体目标是1）。评价机制，动力学，和关键因素负责管理ASC介导的血管网络形成的EC在体外和体内; 2.）评估ASC或ASC亚群通过直接旁分泌支持在体外和体内支持胰岛功能的能力;以及通过ASC和EC在体内组装嵌合人血管网络来进一步保留胰岛功能的能力;以及3.）确定糖尿病和衰老对人ASCs参与体内嵌合血管生成能力的影响，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共移植可以帮助组织存活的程度;并通过使用胰岛移植作为模型，将允许评估胰岛移植是否可以通过ASC和它们可以帮助形成的血管网络显着增强。此外，本研究将阐明从糖尿病患者中获得的自体ASC通过旁分泌效应或血管化促进组织存活的潜力;并确定糖尿病中ASC功能受损的关键分子机制。这些功能的显着损害凸显了对涉及自体ASC或同种异体ASC的靶向修饰的方法的需要。

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.