A clinical scalable cryopreservation method of adipose tissue for reconstructive surgery assessed by stromal vascular fraction and mice studies

Abstract

Background: Adipose tissue is widely used in plastic surgery. The main obstacle is that it can be used only immediately after liposuction, while reconstruction often requires several procedures to achieve optimal results. This study aimed to develop a cryopreservation protocol directly applicable to clinical situations, allowing repetitive procedures without multiple tissue harvests.

Methods: The authors first tested scalable bags suitable for therapeutic uses. All subsequent experiments were performed in those bags. The authors evaluated in vitro, on the basis of cell viability, cell number, phenotype, and stromal cell proliferation, the efficacy of six cryopreservation media composed of an external cryoprotectant (human albumin or hydroxylethyl starch) with or without an internal cryoprotectant (dimethyl sulfoxide). Two storage temperatures (-196°C and -80°C) were tested in vitro and in vivo (subcutaneous graft in 30 nude mice) with the selected medium.

Results: The combination of 5% dimethyl sulfoxide and 95% hydroxylethyl yielded in vitro results that were good and the most consistent. With this cryoprotective solution, the authors observed no significant difference in vitro for a storage period of 7 days. When the storage was extended to 1 month, the cell viability was decreased by 10 percent for both storage temperatures. The in vivo experiments assessed the superiority of cryopreservation at -80°C with less graft resorption (60 percent and 70 percent, respectively, for -80°C and -196°C) and less fibrosis.

Conclusion: The study's protocol with a chemically defined cryoprotective solution, specific scalable bags constrained in an aluminum holder, and a storage temperature of -80°C is promising for long-term adipose tissue cryopreservation.