Quantification of Mesenchymal Stem Cell Loss During Autologous Fat Graft Processing: Implications for Regenerative Cell Preservation
Year: 2026
Type: article
Abstract: Background: Autologous fat grafting is widely utilized in aesthetic and reconstructive surgery; however, graft retention remains highly variable and unpredictable, with reported long-term resorption rates reaching 90%. Adipose-derived mesenchymal stem/stromal cells (MSCs) play a pivotal role in improving graft survival through pro-angiogenic, anti-apoptotic, and immunomodulatory mechanisms. Although cell enrichment techniques have been extensively explored, the magnitude of MSC loss occurring during routine clinical preparation protocols remains poorly quantified. This prospective pilot study aimed to identify and quantify MSC loss across sequential stages of lipoaspirate processing and establish evidence-based strategies to optimize intraoperative cell retention. Methods: Thirty-six biological and fluid fractions were obtained from nine adult patients undergoing elective autologous liposuction. Harvested specimens were subjected to either standard washing or closed-system mechanical microfragmentation (Lipogems®), followed by secondary processing using enzymatic digestion or mechanical shear dissociation. Adherent nucleated cells were expanded in primary culture, enumerated, and immunophenotypically profiled via flow cytometry (FACS) utilizing a combined surface marker panel (CD31⁻CD45⁻CD44⁺CD73⁺) to determine MSC-like cell yields. Results: Microfragmented adipose tissue processed using the Lipogems® kit maintained an MSC density comparable to that of standard enzymatically digested fat (99.6% vs. 100%, p = 0.263). Crucially, a substantial proportion of viable MSC-like cells was recovered from the discarded microfat wash liquid (66.1% relative to the standard fat reference), demonstrating marked cellular loss during the intra-device irrigation step. Secondary mechanical dissociation of washed fat into nanofat resulted in an MSC retention of 32.1%, whereas primary centrifugation pellets yielded only 7.1%. Conversely, discarded lipoaspirate infranatant fluid and standard fat wash liquid contained minimal cellularity (<5%). Combining microfat with its discarded wash effluent yielded a cumulative cellularity of 165.7% relative to standard lipoaspirate. Conclusion: Progenitor cell loss in autologous fat grafting occurs predominantly during post-fragmentation washing and secondary centrifugation steps. Restricting irrigation to the pre-fragmentation phase and avoiding unnecessary secondary centrifugation can substantially improve cellular preservation. Furthermore, intraoperative salvage and concentration of the MSC-rich wash fraction represents an accessible, non-enzymatic strategy to augment graft cellularity and potentially improve clinical outcomes.
Source: Biomedical Research and Therapy
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7225856429