Effects of fat preparation methods on the viabilities of autologous fat grafts.

Fat grafts are commonly used in plastic surgery, but their unpredictable absorption rates are a considerable disadvantage. Furthermore, no agreement has been reached regarding the method that best enables fat graft survival. This study aimed to evaluate the effects of different preparation methods on fat graft viability. Fat tissue was harvested from the remnants of transverse rectus abdominis musculocutaneous (TRAM) flaps by syringe aspiration. Harvested fat tissue was prepared using three different methods: centrifugation, metal sieve concentration, and cotton gauze concentration. To evaluate the viabilities of fat cells, XTT assays were performed. For the study, 18 nude mice were allocated to three groups: the centrifugation, metal sieve, and cotton gauze groups (6 mice per group). Prepared fat (1 ml) was injected into the nuchal area of the mice, and 12 weeks later, grafts were dissected to determine graft survival rates and subjected to histologic analysis. No significant differences were observed in graft survival rates and histologic findings (necrosis and vascularity) between the three groups. However, histologic analysis found the metal sieve group to have significantly lower fat cell viability and more inflammation than the other two groups. The findings suggest that the closed centrifugation technique has no advantage over the open cotton gauze technique in terms of fat graft viability, and that the metal sieve concentration method is deficient as a preparation method because it can cause grafted fat degradation.

The effect of topically applied recombinant human growth hormone on wound healing in pigs.

The beneficial wound healing effect of the systemic growth hormone (GH) mediated by insulin-like growth factor 1 (IGF-1) has been widely reported. Recent studies have suggested that GH facilitates wound healing not by circulating IGF-1, but by local IGF-1 produced in the wound itself. The aim of this study was to define whether the locally administered GH could accelerate the wound-healing rate. Full-thickness skin defects (diameter 4 cm) were made in the back of micropigs, and GH (2.5 IU/L) was applied every other day for 3 weeks (11 times total). Control wounds were given the vehicle only. The wound sizes were measured weekly by planimetry and biopsies were taken. The wound sizes were significantly reduced in the GH-treated groups as compared with the control group (P < 0.05) each week. Histological and immunohistochemical examination revealed that the production of IGF-1 and collagen 1 in the experimental group increased more than in the control group. The present results suggest that local treatment with GH effectively accelerates wound healing.