BACKGROUND: Stromal vascular fraction (SVF) of fat tissue contributes to skin antiaging and rejuvenation, but standard isolation methods have not yet been established for obtaining clinical-grade cells.1 Tissue enzymatic digestion is now the most widely used method. However, most published protocols employ research-grade collagenase containing xenogeneic components, which may cause severe anaphylaxis, immune reactions, or infections in patients.2 And for some products, the enzymatic composition shows lot-to-lot variability that may affect reproducibility.3 In this study, we utilized a new type of clinical-grade collagenase to determine its suitability and efficacy. Furthermore, we conducted a clinical trial to evaluate the ultrastructural improvement of facial skin after transplantation of autologous SVF isolated by the new collagenase.
MATERIALS AND METHODS: This new type of clinical-grade collagenase mainly consists of aseptically filled, highly purified collagenase, which has been applied to loosen hypertrophic scars. Collagenase NB4 (Sigma) was used as control. For in vitro study, adipose tissue specimens were obtained with informed consent from women undergoing elective liposuction (n = 5). SVF was isolated according to the published methods with some minor modifications, its yield and viability was detected. Then SVF was cultured and expanded to adipose stem cells (ASCs), the immunophenotype and differentiation potential was also evaluated. Our clinical trial was conducted in 13 patients aged between 30 and 56 years old. All of the cases underwent the lipoaspiration procedure from the abdomen. SVF was isolated and transplanted at dose of 2.5 × 107 nucleated cells in one side of the fronto-temporal area, the other side was used as self-control. The changes in the skin were analyzed by VISIA and patients’ self-assessment.
RESULTS: There are no statistically significant differences on yield and proliferation of SVF isolated by the new collagenase and Collagenase NB4. No morphologic differences were found in cells throughout the entire culturing time. ASCs surface markers expression was similar between 2 products. And the differentiation potential of the cells was not affected, which was consistent with previously published results. By administration of autologous SVF isolated by new collagenase, the elasticity and density of skin were improved significantly. The score of VISIA showed slight changes in wrinkle scores. Furthermore, most patients thought that the skin texture of treatment area was improved.
CONCLUSION: We concluded that this new type of clinical-grade collagenase can replace current research-grade products without any negative effect in the yield or function of SVF, which can be applied to antiaging and rejuvenation of facial skin.
REFERENCES:
1. Zarei F, Abbaszadeh A. Application of cell therapy for anti-aging facial skin. Curr Stem Cell Res Ther. 2019;14:244–248.
2. Carvalho PP, Gimble JM, Dias IR, et al. Xenofree enzymatic products for the isolation of human adipose-derived stromal/stem cells. Tissue Eng Part C Methods. 2013;19:473–478.
3. McCarthy RC, Breite AG, Green ML, et al. Tissue dissociation enzymes for isolating human islets for transplantation: factors to consider in setting enzyme acceptance criteria. Transplantation. 2011;91:137–145.