The Cd146+ Subpopulation Of Adipose-derived Stromal Cells (ascs) Has Enhanced Regenerative Effects
Mimi R. Borrelli, Charles Blackshear, Stephanie Vistnes, Ronak A. Patel, Jan Sokol, Dung Nguyen, Arash Momeni, Michael T. Longaker, Derrick C. Wan.
Stanford, Palo Alto, CA, USA.
PURPOSE: Adipose-derived stromal cells (ASCs) are cells within the stromal vascular fraction (SVF) of adipose tissue that have extensive proliferative capacity and multilineage differentiation abilities. Recent work indicates ASCs are a heterogeneous mix of cells comprised of multiple stem and progenitor subpopulations. Further elucidation of the identity and regenerative capacities of each ASC subpopulation can inform therapeutic strategies to specifically target the more regenerative subpopulations.
METHODS: Linear discriminant analysis was performed on single cell transcriptional data to identify CD146 as cell surface marker which correlated with an angiogenic gene expressing cluster. Flow cytometry was used to isolate CD146+ ASCs from human lipoaspirate samples (n=3). Gene expression analysis was compared between CD146+ ASCs, CD146- ASCs, and unsorted fat cells, for proangiogenic (ANGPT1, VEGF, FGF) and adipogenic (PPARg, LPL, FABP4) factors. To explore the in vivo regenerative potential of CD146+ ASCs, 200ul of human lipoaspirate was enriched with either CD146+ ASCs, CD146- ASCs, unsorted ASCs, (10,000cells/200ul), or was not enriched, and injected into the subcutaneous tissue overlying the scalp of recipient immunodeficient mice. Graft retention was followed by CT scanning every two weeks for a total of 8 weeks, at which point the fat grafts were explanted and processed for histology.
RESULTS: CD146+ ASCs showed a significant upregulation of VEGF and LPL expression compared to unsorted fat cells (*p < 0.05) and CD146- ASCs (***p < 0.005) (Fig. 1A). Fat enriched with CD146+ ASCs had significantly higher retention compared to fat alone or fat grafts supplemented with CD146- ASCs (Fig. 1B). Fat grafts isolated from mice transplanted with CD146+ ASCs showed the greatest CD31 immunofluorescent staining.
CONCLUSION: We have identified a subpopulation of ASCs positive for CD146 with enhanced angiogenic effects. These effects are likely mediated by increased expression of proangiogenic factors such as VEGF. These findings suggest that enriching lipoaspirate with CD146+ ASCs may enhance fat graft vascularization and retention in the clinical setting.
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