Role of anatomical region and hypoxia on angiogenic markers in adipose-derived stromal cells.

Abstract

Recent research into adipose-derived stem cells (ASCs) suggests that anatomical location has a major impact on the metabolic profile and differentiation capacity of ASCs. By having a better understanding of how various ASCs respond to cellular stressors such as hypoxia, which are induced during routine surgical procedures, we can facilitate future development of cell-based therapies to improve wound healing. Human ASCs were isolated from the superficial and deep adipose layers of four patients undergoing elective abdominoplasty. ASCs were cultured in hypoxic (1% O2, 5% CO2, and 94% N2) conditions. After 12 and 48 hours, ASCs were assessed for markers of angiogenesis by mRNA levels of vascular endothelial growth factor A (VEGF-A), vascular endothelial growth factor B (VEGF-B), and hypoxia inducible factor 1 α (HIF-1α). Western blot analysis was performed to assess levels of VEGF-A, p-NF-κB, and NF-κB. In addition, in vitro analysis of angiogenesis was performed using Matrigel assay (BD Biosciences, Franklin Lakes, NJ). We observed significant increases in deep ASC's VEGF-A, VEGF-B, and HIF-1α mRNA expression compared with the superficial layer after 24-hour hypoxia (p < 0.05). Similar results were found when examining protein expression levels, with the deep ASCs expressing significantly larger amounts of VEGF-A and p-NF-κB (p < 0.05) compared with the superficial layer. Our results suggest that significant variations exist in the angiogenic profile of superficial and deep ASCs. We demonstrate that superficial ASCs are less prone to transcribe potent chemokines for angiogenesis, such as VEGF-A, VEGF-B, and HIF-1α and are less likely to translate VEGF-A and NF-κB. This may help with the selection of specific stem cell donor sites in future models for stem cell therapy.