Biochemical assessment of cellular damage after adipocyte harvest

Free fat transplantation for soft tissue augmentation yields variable results, which may be related to the technique of fat harvest. To compare the viability of adipocytes harvested by liposuction (sal) or by excision (exc), fat harvested by both techniques from seven lipectomy patients was analyzed by glycerol-3-phosphate dehydrogenase (G3PDH) enzyme assay. Leakage of this lipogenic enzyme through the plasma membrane is a potential indicator of fat cell damage. Preliminary experiments showed this assay to be sensitive and specific for adipocyte G3PDH activity. Treatment of fat tissue with collagenase H resulted in complete release of the component fat cells for analysis with less loss of G3PDH activity, compared to other collagenase preparations. Each sample was digested and separated into three compartments: mature adipocytes-floating layer (F), acellular supernatant (S), and stromal pellet (P). Samples from each compartment were assayed for G3PDH activity, normalized to DNA content, and represented as a percentage of the whole (F + S + P). Within the subgroups, the fat cell fraction of the liposuction samples (Fsal) showed statistically more activity than the excised samples (Fexc) by paired Student's t test (P = 0.004). The supernatant (representing leaked G3PDH) and pellet fractions of excised samples revealed more G3PDH activity than the same fractions from liposuctioned tissue; the former (Sexc) to a significant degree (P = 0.036). Using this assay, the results indicate that liposuction fat harvest does not result in increased fat cell damage compared to fat harvested by excision.