Impact of Hyperglycemia and Low Oxygen Tension on Adipose-Derived Stem Cells Compared with Dermal Fibroblasts and Keratinocytes: Importance for Wound Healing in Type 2 Diabetes

AIM: Adipose-derived stem cells (ASC) are currently proposed for wound healing in those with type 2 diabetes mellitus (T2DM). Therefore, this study investigated the impact of diabetes on adipose tissue in relation to ASC isolation, proliferation, and growth factor release and the impact of hyperglycemia and low oxygen tension (found in diabetic wounds) on dermal fibroblasts, keratinocytes, and ASC in vitro. METHODS: Different sequences of hypoxia and hyperglycemia were applied in vitro to ASC from nondiabetic (n = 8) or T2DM patients (n = 4) to study cell survival, proliferation, and growth factor release. Comparisons of dermal fibroblasts (n = 8) and keratinocytes (primary lineage) were made. RESULTS: No significant difference of isolation and proliferation capacities was found in ASC from nondiabetic and diabetic humans. Hypoxia and hyperglycemia did not impact cell viability and proliferation. Keratinocyte Growth Factor release was significantly lower in diabetic ASC than in nondiabetic ASC group in each condition, while Vascular Endothelial Growth Factor release was not affected by the diabetic origin. Nondiabetic ASC exposition to hypoxia (0.1% oxygen) combined with hyperglycemia (25mM glucose), resulted in a significant increase in VEGF secretion (+64%, p<0.05) with no deleterious impact on KGF release in comparison to physiological conditions (5% oxygen and 5 mM glucose). Stromal cell-Derived Factor-1α (-93%, p<0.001) and KGF (-20%, p<0.05) secretion by DF decreased in these conditions. CONCLUSIONS: A better profile of growth factor secretion (regarding wound healing) was found in vitro for ASC in hyperglycemia coupled with hypoxia in comparison to dermal fibroblasts and keratinocytes. Interestingly, ASC from T2DM donors demonstrated cellular growth rates and survival (in hypoxia and hyperglycemic conditions) similar to those of healthy ASC (from normoglycemic donors); however, KGF secretion was significantly depleted in ASC obtained from T2DM patients. This study demonstrated the impact of diabetes on ASC for regenerative medicine and wound healing.