Adipose Aspirates as a Source for Human Processed Lipoaspirate Cells after Optimal Cryopreservation

Background: The purpose of this study was to test the authors' hypothesis that previously cryopreserved adipose aspirates collected from conventional liposuction could still be a reliable source of human processed lipoaspirate cells. Methods: Adipose aspirates were collected from 12 adult female patients after conventional liposuction of the abdomen and were then preserved by an optimal cryopreservation method with added cryoprotective agents (0.5 M dimethyl sulfoxide and 0.2 M trehalose). Cryopreservation of the adipose tissues was subsequently conducted with controlled slow cooling and then stored in liquid nitrogen (–196°C). One gram of fresh or cryopreserved (after fast rewarming) adipose aspirates was processed in vitro and the resulting cell pellet, consisting of processed lipoaspirate cells, was cultured separately. The length of time until processed lipoaspirate cells became adherent to the culture plate was recorded and the number of processed lipoaspirate cells after a 2-week culture was counted. Results: Flat, spindle-shape processed lipoaspirate cells from the cryopreserved group became adherent to the plate within 48 to 72 hours after initial culture compared with the fresh group, where the cells became adherent by 24 hours. After a 2-week culture, the cryopreserved aspirates yielded an average of 3.7 ± 1.4 × 105 processed lipoaspirate cells per milliliter, equal to 90 percent of the yielded number of cells obtained from the fresh aspirates (4.1 ± 1.4 × 105 cells/ml). Conclusions: The authors' results indicate that although there is a latency of cell growth after an optimal cryopreservation, cryopreserved adipose aspirates can yield a significant number of processed lipoaspirate cells compared with fresh aspirates and may be a reliable source of human processed lipoaspirate cells because they can still be processed later after long-term preservation.