Distribution of adipose-derived stem cells in adipose tissues from human cadavers

Background: Adipose-derived stem cells (ASCs) possess multipotency in vivo and in vitro, and thus are thought to be very promising precursors for use in regenerative medicine. ASCs can be concentrated from adipose tissue by enzymatic digestion and transplanted to increase angiogenesis or for cosmesis. ASC transplants are now being performed in a clinical setting. Although data on ASCs are extensive, the distribution of ASCs in human fat tissue has not been fully clarified. Thus, it is important to identify the distribution of ASCs to obtain cell populations rich in ASCs for clinical use. Methods: ASCs express CD34, a cell surface marker. As CD34 is also expressed by endothelial cells, we immunohistochemically stained 2-μm-thick serial paraffin sections of fat tissue obtained from various parts of formalin-fixed cadavers with anti-CD31 and anti-CD34 antibodies to distinguish ASCs from endothelial cells. Results: CD34(+)/CD31(-) cells were mainly found in connective tissue tracts and perivascularly. Among fat tissues obtained from various sites, fat tissues in the thoracic back and lower abdomen were richest in CD34(+)/CD31(-) cells. Conclusion: The concentrations of CD34(+)/CD31(-) cells in adipose tissues differ between sites. The sites most highly enriched for ASCs were identified, and it is now possible to select the best sites for collection of ASCs for transplantation.