Adipose Stem Cells and Platelet-Rich Plasma Induce Vascular-Like Structures in a Dermal Regeneration Template

In the context of biointeractive dressings used for enhancing wound healing, the use of stromal vascular fraction (SVF) or adipose-derived stem cells (ASCs) hereof derived has not been fully exploited yet. Noncultured SVF, a heterogeneous mesenchymal population of cells, is attractive in the field of dermal regeneration because it can be instantaneously obtained, avoids genomic alterations, and is comparatively safer than cultured ASCs. Integra^® Dermal Regeneration Template (DRT) was sprinkled with ASCs in complete medium supplemented with 10% fetal bovine serum (FBS), or SVF, obtained from emulsified or nonemulsified fat, in medium supplemented with 2% platelet-rich plasma (PRP). The presence and differentiation of cells were evaluated by standard histochemistry and immunohistochemistry, whereas conditioned media were analyzed for vascular endothelial growth factors (VEGF) by ELISA. In vitro experiments were conducted to analyze ASC proliferation in the presence of either FBS or PRP. Deposition of ASCs in medium supplemented with FBS caused their integration into Integra DRT as early as 1 h. ASCs were found as aggregates until 6-10 days without forming organized structures. When seeded onto Integra DRT, SVF cells in medium supplemented with PRP formed aggregates at early times, which at 7 and 10 days organized into vascular-like structures, lined by CD31⁺ and smooth muscle actin-positive cells. With nonemulsified fat, the lacunar structures did not show an organized distribution of SVF cells. PRP induced ASC proliferation although at lower level than FBS. VEGF secretion was enhanced when fat emulsification was introduced into the protocol. In conclusion, the combination of SVF cells obtained from emulsified fat, PRP, and Integra DRT exhibit synergistic effect on the formation of vessel-like structures indicating a step forward aimed at regenerative surgery for chronic wound healing.