The use of the "stem graft" in chronic wounds: in vitro analysis, clinical and comparative study

BACKGROUND Chronic wounds are a major issue. Fat grafting is an emerging treatment and several techniques were developed to concentrate adipose-derived stem cells (ADSCs). Enzymatic processing and hardware may be expensive or forbidden. The aims of the study were to obtain an ADSCs-rich injectable matrix by minimal manipulation of lipoaspirate, and to assess its efficacy in chronic wounds. METHODS Nine patients undergoing abdominal liposuction were enrolled. Decanted fat and "stem graft" (SG) were analyzed by cytofluorimetry. Stem cells were cultured and differentiated. Forty patients affected by venous ulcers were randomized into 4 groups: polyurethane foam (PF), stem graft (SG), porcine dermis (PD), Polynucleotides-added hyaluronic acid (PAHA). Post-operative wound area reduction was analyzed. Biopsies were performed and specimens stained with hematoxylin/eosin, Masson trichrome, immunohistochemistry for a-SMA, CD34, Ki67, collagen. RESULTS One cc of SG was obtained by 10 cc of lipoaspirate. The mean content of CD34+CD45- cells in SG was higher than in decanted fat (9.2% (± 2.1) vs 2.5% (±3.8), p <0.05). Cells from SG were able to differentiate in adipocytes and osteoblasts. Compared to pre-operative values, wounds treated with SG showed significant wound area reduction (p <0.01), increased CD34, Ki67 and collagen expression (p <0.01, p <0.01 and p <0.05). In the SG group: wound area reduction was higher than in PF (p <0.01); post-operatively, Ki67 expression was higher than in PF group (p <0.01), collagen expression higher than PF and PAHA groups (p <0.01 and p <0.01, respectively); CD34 expression was lower than in PD group (p <0.01), while a-SMA lower than in PD and PAHA groups (p <0.05 and p <0.05) CONCLUSIONS The Stem Graft proved to be a simple and effective technique to address non-healing wounds. It is autologous, thus preventing possible allogenic or allergic reaction, and cheap. From a biological standpoint, it may reduce the length of the inflammatory and early proliferative phases of wound healing, typically characterised by neo-angiogenesis and myofibroblast proliferation, with faster progression to the remodelling phase