Preparation of gel containing human adipose derived stem cells and its clinical efficacy for adherent scar

Objective To investigate the clinical effectiveness of stromal vascular fraction gel (SVF-gel) containing human adipose derived stem cells (ADSCs) in the treatment of adherent scar. Methods A retrospective analysis was carried out on the patients with adherent scars meeting our inclusion criteria and undergoing the treatment of gel injection during June 2018 and June 2020. The SVF-gel was prepared from the lipoaspirates sucked from the abdomen or the thigh followed by filtration, centrifugation and emulsion, and then injected into the adherent scars (at an interval of 2 mm for every needle puncture, SVF-gel 0.02 mL for every dose). Small amount of granular adipose tissues and SVF-gel were digested, cultured and identified. The scar hardness and thickness were measured for every patient preoperatively and 6 months postoperatively. Patient and observer scar assessment scale (POSAS) was used to evaluate scar condition, and patient satisfaction was investigated. Results There were 8 patients enrolled in this study, with a total of 10 adherent scars and the area of depression of 5.56±4.50 cm2. The injection volume of SVF-gel under the adherent scar was 3.90±3.00 mL. The results of morphological observation showed that short spindle cells grew in both SVF-gel and granular fat after digestion, and the over 95% obtained cells expressed the specific markers of mesenchymal stem cells, CD73, CD90 and CD105. At the same time, the number of primary cells cultured in same volume of SVF-gel was larger than the number from the granular fat tissue. Differentiation study found the growth of adipose-like cells in vitro, which were positive to oil red O staining. The scar hardness was decreased from 48.13±20.59 shore units preoperatively to 30.96±15.66 shore units in 6 months postoperatively(P < 0.05), and the scar skin thickness was increased from 2.00±0.60 mm to 2.72±0.63 mm (P < 0.05). In 6 months after operation, the appearance and activity of scar skin were significantly improved, and no complications were observed. The scores of patient scar assessment scale (PSAS) and observer scar assessment scale (OSAS) were 12.0±2.8 and 13.7±3.9 respectively, and the patient satisfaction score was 4 to 5, with an average of 4.6. Conclusion Our prepared SVF-gel contains more active ADSCs. Its injection can improve the local depression and scar texture in the adherent scar and achieve good satisfaction in the patients.