Influence of repeated aspiration on viability of fat grafts: a comparative study.

BACKGROUND Fat grafting has been increasingly widely used in cosmetic and reconstructive surgery. However, the long-term retention of fat grafts is still unpredictable. Many critical variables have been found to significantly affect the viability of fat grafts; still, some of the ordinary impact factors are overlooked. OBJECTIVES We performed this study to find out whether repeated aspiration had an impact on fat grafts through an in vitro analysis and a nude mouse model. METHODS A 15 cm by 10 cm rectangle was marked at the lower abdomen. The cannula was gently advanced and retracted through the same incision in a fan fashion within the superficial layer to collect fat samples. Based on the sequence of harvesting, the collected adipose tissue was divided into five groups and labeled as syringes 1, 2, 3, 4, and 5. Part of the sample was dissociated and analyzed using cell staining, Cell Counting Kit-8 assay, and flow cytometry. The other part was injected in vivo and analyzed for weight and histology at varying time intervals. RESULTS Fat grafts from the former syringes were presented with a greater number of viable adipocytes and a higher level of cellular function compared to the latter syringes. Additionally, fat grafts from former syringes had higher graft retention, better vascularity, and less cystic necrosis. Neither the viability of stromal vascular fractions (SVFs) nor the ratio of CD34 + CD45- cells within the SVFs were different among the five groups. CONCLUSIONS Repeated aspiration had a negative impact on the adipocytes, but not on the SVFs. With an increasing time of aspiration, the viability of the adipocytes and long-term retention of fat grafts decreased gradually. Harvested fat grafts from the first few syringes may be more suitable for fat grafting.