"Quality and Quantity-Cultured Human Mononuclear Cells Improve the Human Fat raft Vascularization and Survival in an In Vivo Murine Experimental Model".

BACKGROUND Ischemia of fat grafts with subsequent necrosis impedes us from having satisfying long-term results. The Quality and Quantity (QQ) culture is a 1-week cell culture which increases the vasculogenic potential of peripheral blood mononuclear cells (PBMNC). This in vivo murine model investigates whether enrichment with QQ-cultured human MNCs (MNC-QQ) improves the vascularization in the human fat graft through vessel integration and paracrine mechanisms, and whether this decreases the tissue loss. METHODS Human adipose tissue, PBMNC, MNC-QQ and stromal vascular fraction (SVF) were prepared. Firstly, PBMNC, MNC-QQ and SVF were compared in vitro for vasculogenic potential by EPC colony-forming assay and EPC culture assay. Secondly, 0.25g fat grafts were created with 1x10 PBMNC (N=16), 1x10 MNC-QQ (N=16), 1x10 SVF (N=16) or PBS as control (N=16) before grafting in BALB/c nude mice. Grafts were explanted after 1 and 7 weeks, and analyzed for weight persistence; for vessel formation by CD31 immunohistochemistry; and for angiogenic markers by qPCR. RESULTS MNC-QQ develop more definitive EPC colonies (4.00±0.97/dish) than PBMNC (0.78±0.15/dish; p<0.01) and SVF (none), and more functional EPCs (74.7±8.7/field) than PBMNC (25.6±1.7/field; p<0.01) and SVF (11.7±4.4/field; p<0.001). Weight persistence after 7 weeks was significantly higher in grafts with MNC-QQ (89.8±3.5%) or SVF (90.1±4.2%) compared to control (70.4±6.3%, p<0.05). MNC-QQ-enriched grafts had the highest vessel density (96.6±6.5 vessels/mm; control: 70.4±5.6 vessels/mm; p<0.05). MNC-QQ exerted a direct vasculogenic effect through vascular integration, and a potential paracrine VEGF-mediated effect. CONCLUSIONS QQ-cultured MNCs containing EPCs stimulate fat graft vascularization and enhance graft survival in a rodent recipient.