Autologous fat transfer: The progenitor cell response to different recipient environments

Abstract

Background: Autologous fat transfer is a common procedure; however, results are variable and unpredictable. Objectives: Stem cell responses to hypoxic environments need to be elucidated to determine which cell types contribute to graft survival. Methods: Acellular dermal matrix (ADM) envelopes were implanted in the subcutaneous tissues of 4 swine. In each swine, 2 envelopes were inserted as controls (ADM group), and 2 were placed and injected with 5 mL of autologous fat (ADM/fat group). Two additional envelopes were inserted and filled with 5 mL of fat and an omental pedicle (A/F/O group). Animals were sacrificed and the envelopes excised at 1, 2, 4, and 16 weeks. Specimens were analyzed histologically and/or with flow cytometry. Results: Fat was retained in ADM envelopes with and without a pedicle blood supply, although the percentage of volume retention was greater in the pedicled group. The peak number of mesenchymal progenitor cells within the ADM/fat group was significantly greater than the peak in the A/F/O group (P =.044), whereas endothelial progenitor cells in the ADM/fat group showed a prolonged increase through 4 weeks (P =.015 vs the A/F/O group at week 4). At 16 weeks, the interior surface of the matrix in the ADM/fat group had significantly more blood vessels than that of the ADM or A/F/O group (P = .0021 and .0036, respectively). Conclusions: Injecting fat into hypoxic environments significantly increases the mesenchymal and endothelial progenitor cell responses and enhances the formation of blood vessels. © 2014 The American Society for Aesthetic Plastic Surgery, Inc.