Background: 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.
Methods: 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).
Results: 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.
Conclusions: 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.