The use of higher proportions of platelet-rich plasma to enrich microfat has negative effects: A pre-clinical study.

INTRODUCTION Platelet-rich plasma (PRP) improves engraftment after fat transfer. However, the effects of platelet dose have never been investigated. We used magnetic resonance imaging (MRI) to compare surviving graft volumes in mice after administration of four different formulations (microfat alone, and three PRP-enriched microfat mixes). METHOD We used a random, double-blinded, fat transfer protocol employing three different platelet levels: 1 (low-dose; LD), 500 (medium-dose; MD), and 1,000 million (high-dose; HD) platelets/mL, and fat alone (control; Cx). We grafted 0.4 mL of the 70/30 PRP-enriched microfat mixtures (0.4, 200 and 400 million platelets per 0.12 mL for the LD, MD and HD mixtures respectively) or 0.4 mL of microfat alone into 22 nude mice and monitored surviving graft volumes every month for 3 months. Then we histologically analyzed all grafts to assess neo-angiogenesis status and fat integrity RESULTS:: Three-dimensional MRI showed that the median surviving graft volumes at 3 months were 9.5 [0;25]% (p=0.003) (HD), 4.1 [0;18]% (p=0.001) (MD), and 18 [8;38]% (p= 0.41) (LD) compared to 36 [28;53]% for the Cx value. The histological integrity of microfat-alone grafts was significantly better than those of the other grafts, although the HD and LD grafts exhibited higher levels of neo-angiogenesis. CONCLUSION Higher platelet levels in microfat grafts were associated with poor graft survival in nude mice; a clinical review would be appropriate.