Effects of Cryopreservation on Stromal Vascular Fraction Viability in Human Adipose Tissue: Insights from a Systematic Review.

Abstract

Background: Cryopreservation of human adipose tissue facilitates long-term storage and repeated clinical application in tissue engineering and regenerative medicine. However, its quantitative impact on stromal vascular fraction (SVF) viability remains inconsistently characterized across studies with heterogeneous reporting formats. This study systematically evaluated the effect of cryopreservation on SVF viability and key procedural and donor-related determinants influencing post-thaw preservation quality.

Methods: A systematic search of PubMed, Scopus, Web of Science, Cochrane Library, and ScienceDirect (January 2008-January 2025) identified in vitro and in vivo studies assessing cryopreserved human adipose tissue. Methodological quality was evaluated using the Joanna Briggs Institute (JBI) critical appraisal tools. Quantitative synthesis included a meta-analytic pooling of available comparable datasets alongside exploratory correlation analyses to examine associations between cryopreservation parameters and SVF viability.

Results: Seventeen studies met inclusion criteria, with six eligibles for quantitative meta-analysis. Pooled SVF viability was 0.062 × 10⁵ cells/g (95% CI 0.50-0.74 × 10⁵) in cryopreserved samples and 0.054 × 10⁵ cells/g (95% CI 0.42-0.65 × 10⁵) in fresh tissue, with substantial heterogeneity (I² > 98%). Viability negatively correlated with freezing duration (r =  - 0.644) and prolonged enzymatic digestion (r =  - 0.417), whereas freezing temperature showed minimal effect (r =  - 0.093). Short-term storage (< 1 month), lower temperatures (- 80 °C or - 196 °C), and cryoprotectants such as DMSO and trehalose improved preservation outcomes.

Conclusion: Cryopreservation preserves SVF viability at levels broadly comparable to fresh tissue, likely due to methodological variability across studies rather than true biological superiority in regenerative capacity. Post-thaw SVF quality is influenced more by cumulative processing and storage conditions than by freezing temperature alone. However, standardization of protocols and incorporation of functional potency assays beyond viability metrics are still essential to optimize clinical adipose tissue biobanking.