Investigating the Viability of Fat Cells Over 1, 3, and 6 Months After Freezing at −18°C

Background

Lipofilling is a natural, low-risk, and long-lasting method for filling, reconstructing, and improving soft tissues such as the face, with minimal discomfort for patients. Many plastic surgeons prefer autologous fat grafting in aesthetic surgery due to its availability, cost-effectiveness, biocompatibility, and absence of allergic and carcinogenic concerns. Despite the advantages of autologous fat injection, one of the main drawbacks is the variable persistence of injected fat tissue. Given the significant implications of this issue in advanced countries, this study aims to investigate the survival of fat cells after freezing at different time intervals (1, 3, and 6 months).

Methods

Thirty female participants were enlisted for this research, and the viability of fat cell specimens was assessed at intervals of 0, 1, 3, and 6 months post-freezing at −18°C. The evaluation of viable adipocytes was conducted using the XTT assay, a live/dead staining method using fluorescence microscopy after staining with fluorescein diacetate (FDA) and propidium iodide (PI), along with histological analysis of fat tissue after freezing at the indicated time intervals.

Results

The results showed that the viability of frozen fat samples decreases by 34%, 60%, and 80% after 1, 3, and 6 months, respectively, compared to non-frozen samples on Day 0.

Conclusions

The findings of this study underscore a rapid decline in adipocyte viability after storage at −18°C at different time intervals (1, 3, and 6 months), at which points only around 60%, 40%, and 20% of fat cells remained viable, respectively. These results suggest that current fat preservation techniques utilizing either a −18°C freezer are not sufficient for maintaining the long-term viability of adipocytes, and alternative cryopreservation methods are needed to preserve fat cells.