Dysfunction of endothelial precursor subtypes dictates the outcomes of diabetic r

描述（申请人提供）：内皮祖细胞（EPC）功能障碍可能在DR的发病机制中具有关键作用。由培养的单核细胞（MNC）产生的两个EPC群体是晚期生长内皮细胞（OEC），其显示克隆表型并且属于CD 34 + CD 45-群体;以及早期EPCs（eEPCs），其表现出单核细胞表型（CD 14 +/CD 45+），但在体外和体内显示出内皮样标志物和行为。为了解决这些细胞在糖尿病视网膜病变（DR）中的作用，我们假设在DR中，eEPCs仍然是OEC的中心调节剂;然而，OEC群体在非增殖性糖尿病视网膜病变（NPDR）中短暂丢失，但它重新出现作为一个更具攻击性和增殖性的群体，触发“血管生成”转换和增殖性（PDR）的发生。相比之下，eEPC群体从未完全消失，而是其活性水平发生变化，在PDR中更具炎症性，而在NPDR中较少。在这两个群体中，一氧化氮合酶（NOS）的失调是这些表型转变的核心，这进一步受到骨髓（BM）微环境变化的影响。具体目的1：检测eEPC和OEC的增殖潜力是否取决于视网膜病变的阶段，并确定从糖尿病个体分离的eEPC和OEC是否产生更多的活性氧，含有更多的内源性NOS抑制剂，并分泌与对照细胞不同的细胞因子谱。具体目标二：为了测试非糖尿病（健康）eEPC和OEC的组合是否将具有比在视网膜缺血-再灌注损伤模型中或在糖尿病SCID小鼠的脱细胞毛细血管中单独的群体更大的修复功能。具体目标3：测试糖尿病中的eEPC和OEC功能障碍是否是由于BM微环境中的缺陷（肥胖增加、造血减少和祖细胞功能障碍）所致。这些研究将使我们能够确定eEPCs和OECs是否代表细胞治疗的理想祖细胞群体，以改善糖尿病眼睛中血管系统的健康。

DESCRIPTION (provided by applicant): Endothelial progenitor cell (EPC) dysfunction may have a key role in the pathogenesis of DR. Two populations of EPCs that arise from cultured mononuclear cells (MNC) are the late outgrowth endothelial cells (OECs), which display a clonal phenotype and belong to a CD34+CD45- population; and early EPCs (eEPCs) which exhibit a monocyte phenotype (CD14+/CD45+) but demonstrate endothelial-like markers and behavior in vitro and in vivo. To address the role of these cells in diabetic retinopathy (DR) we hypothesized that in DR, eEPCs remain as the central modulator of the OECs; however, the OEC population is transiently lost in nonproliferative diabetic retinopathy (NPDR) but it reappears as a more aggressive and proliferative population which triggers the "angiogenic" switch and the onset of proliferative (PDR). The eEPC population, in contrast, never disappears entirely but rather shifts in its level of activity, being more inflammatory in PDR and less in NPDR. In both populations, dysregulation of nitric oxide synthase (NOS) is central to these phenotypic transitions, which are further influenced by the changing bone marrow (BM) microenvironment. We are testing this hypothesis by the following aims: Specific Aim 1: To test whether the proliferative potential of eEPCs and OECs depends on the stage of retinopathy and determine whether eEPCs and OECs isolated from diabetic individuals produce more reactive oxygen species, contain more endogenous NOS inhibitors, and secrete a distinct cytokine profile than cells from controls. Specific Aim 2: To test whether the combination of nondiabetic (healthy) eEPCs and OECs will have a greater reparative function then either population alone in models of retinal ischemia-reperfusion injury or in acellular capillaries in diabetic SCID mice. Specific Aim 3: To test whether eEPC and OEC dysfunction in diabetes is due to defects (increased adiposity, reduced hematopoiesis and progenitor dysfunction) in the BM microenvironment. These studies will allow us to determine whether eEPCs and OECs represent ideal progenitor populations for cellular therapy to improve the health of the vasculature in the diabetic eye.