Participation of CD34-enriched mouse adipose cells in hair morphogenesis.

Adipose-derived stromal vascular fraction (SVF) cells are heterogeneous in nature, containing a number of different cell types. Recent studies indicate that CD34 may be a specific marker for adipose-derived mesenchymal stem cells (ADMSCs). Using their participation in hair morphogenesis as a model, the multi-differentiation potential of adult stem cells was investigated. In addition, adipose tissue or adipogenic lineage cells appear to be associated with the hair follicle cycle. The purpose of this study was to test the potential of CD34+ cells enriched from fat tissue in hair morphogenesis. To investigate this, unsorted SVF, CD34+ and CD34- cells sorted from the SVF of green fluorescence protein (GFP) transgenic mice were mixed with fetal mouse keratinocytes and dermal fibroblasts of gestational day 17.5 (E17.5) and then subcutaneously injected into nude mice. The results showed that in the reconstituted skin tissue, larger tissue blocks with more developed hair follicles were observed in the CD34+ cell group compared with the other two groups. Histological and immunofluorescent staining analyses revealed that only CD34+ cells may participate in hair morphogenesis by their integration into dermal sheath structures. However, no involvement in other skin appendages was observed. In addition, differentiation into endothelial cells and participation in blood vessel formation were also observed in both CD34+ and SVF cells, but not in CD34- cells. As expected, participation in adipogenesis was observed in all groups. Our results suggest that CD34+ cells may represent the ADMSCs which possess stronger multiple differentiation potential during reconstituted skin development.