Department of Medicine, Division of Hematology/Oncology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
Cytometry A. 2010 Jan;77(1):22-30. doi: 10.1002/cyto.a.20813.
The in vivo progenitor of culture-expanded mesenchymal-like adipose-derived stem cells (ADSC) remains elusive, owing in part to the complex organization of stromal cells surrounding the small vessels, and the rapidity with which adipose stromal vascular cells adopt a mesenchymal phenotype in vitro. Immunohistostaining of intact adipose tissue was used to identify three markers (CD31, CD34, and CD146), which together unambiguously discriminate histologically distinct inner and outer rings of vessel-associated stromal cells, as well as capillary and small vessel endothelial cells. These markers were used in multiparameter flow cytometry in conjunction with stem/progenitor markers (CD90 and CD117) to further characterize stromal vascular fraction (SVF) subpopulations. Two mesenchymal and two endothelial populations were isolated by high speed flow cytometric sorting, expanded in short term culture, and tested for adipogenesis. The inner layer of stromal cells in contact with small vessel endothelium (pericytes) was CD146+/alpha-SMA+/CD90+/-/CD34-/CD31-; the outer adventitial stromal ring (designated supra adventitial-adipose stromal cells, SA-ASC) was CD146-/alpha-SMA-/CD90+/CD34+/CD31-. Capillary endothelial cells were CD31+/CD34+/CD90+ (endothelial progenitor), whereas small vessel endothelium was CD31+/CD34-/CD90- (endothelial mature). Flow cytometry confirmed these expression patterns and revealed a CD146+/CD90+/CD34+/CD31- pericyte subset that may be transitional between pericytes and SA-ASC. Pericytes had the most potent adipogenic potential, followed by the more numerous SA-ASC. Endothelial populations had significantly reduced adipogenic potential compared with unsorted expanded SVF cells. In adipose tissue, perivascular stromal cells are organized in two discrete layers, the innermost consisting of CD146+/CD34- pericytes, and the outermost of CD146-/CD34+ SA-ASC, both of which have adipogenic potential in culture. A CD146+/CD34+ subset detected by flow cytometry at low frequency suggests a population transitional between pericytes and SA-ASC.
体内培养扩增间充质样脂肪来源干细胞（ADSC）的前体细胞仍然难以捉摸，部分原因是围绕小血管的基质细胞的复杂组织，以及脂肪基质血管细胞在体外迅速采用间充质表型。完整脂肪组织的免疫组织化学染色用于鉴定三个标记物（CD31、CD34 和 CD146），这些标记物共同明确区分血管相关基质细胞的组织学上不同的内圈和外圈，以及毛细血管和小血管内皮细胞。这些标记物与干细胞/祖细胞标记物（CD90 和 CD117）一起用于多参数流式细胞术，以进一步表征基质血管部分（SVF）亚群。通过高速流式细胞术分选分离出两个间充质和两个内皮群体，在短期培养中扩增，并测试其成脂能力。与小血管内皮（周细胞）接触的基质细胞内层为 CD146+/alpha-SMA+/CD90+/-/CD34-/CD31-；外层 Adventitial 基质环（称为 supra adventitial-adipose stromal cells，SA-ASC）为 CD146-/alpha-SMA-/CD90+/CD34+/CD31-。毛细血管内皮细胞为 CD31+/CD34+/CD90+（内皮祖细胞），而小血管内皮细胞为 CD31+/CD34-/CD90-（内皮成熟）。流式细胞术证实了这些表达模式，并显示出 CD146+/CD90+/CD34+/CD31-的周细胞亚群，可能在周细胞和 SA-ASC 之间具有过渡性。周细胞具有最强的成脂潜能，其次是更多的 SA-ASC。与未分选的扩增 SVF 细胞相比，内皮群体的成脂潜能显著降低。在脂肪组织中，血管周围基质细胞组织成两个离散的层，最内层由 CD146+/CD34-的周细胞组成，最外层由 CD146-/CD34+的 SA-ASC 组成，两者在培养中都具有成脂潜能。流式细胞术检测到的低频率 CD146+/CD34+亚群表明存在周细胞和 SA-ASC 之间的过渡群体。
