Influences of preservation at various temperatures on liposuction aspirates

Aspirated fat is not only a filler material but also an abundant source of adipose-derived stem cells. The aim of this study was to assess degeneration of aspirated fat during preservation and optimize the preservation method for lipoaspirates.

Aspirated fat was preserved at room temperature for 1, 2, 4, and 24 hours (n = 10 each); at 4 degrees C for 1, 2, and 3 days (n = 14 each); or at -80 degrees C for 1 month (n = 3). Morphologic changes were assessed with scanning electron microscopy. Adipose-derived stem cell yield was measured after 1 week of culture. For aspirated fat preserved at room temperature, damaged adipocytes were assessed by measuring the oil volume ratio after centrifugation (n = 6) and glycerol-3-phosphate-dehydrogenase activity in washing solution (n = 4). Cell surface marker expression was examined by flow cytometry (n = 3).

Although the scanning electron microscopic assay indicated no remarkable anatomical changes based on preservation methods, oil volume significantly increased in fat preserved at room temperature for 4 hours. Adipose-derived stem cell yield was significantly reduced by preservation at room temperature for 24 hours and by preservation at 4 degrees C for 2 or 3 days. Flow cytometric analysis suggested that the biological properties of adipose-derived stem cells did not significantly change at 4 degrees C up to 3 days. The cells were isolated from cryopreserved fat, but the yield was much less than that from fresh aspirated fat.

Aspirated fat should be transplanted as quickly as possible if it is preserved at room temperature. For adipose-derived stem cell isolation, aspirated fat can be stored or transported overnight if it is preserved at 4 degrees C without adipose-derived stem cell yield loss or changes in biological properties.