Hypertrophic scar is a fibrotic disease following wound healing and is characterized by excessive extracellular matrix deposition. Autologous microfat grafting proves an effective strategy for the treatment thereof as it could improve the texture of scars and relieve relevant symptoms. This study aims to explore the potential mechanisms underlying the anti-fibrotic effect of microfat on hypertrophic scars.
In this study, we injected microfat into transplanted hypertrophic scars in mouse models and investigated the subsequent histological changes and differential expression of mRNAs therein. As for in vitro studies, we co-cultured microfat and hypertrophic scar fibroblasts (HSFs) and analyzed molecular profile changes in HSFs co-cultured with microfat by RNA sequencing. Moreover, to identify the key transcription factors (TFs) which might be responsible for the anti-fibrotic function of microfat, we screened the differentially expressed TFs and transfected HSFs with lentivirus to overexpress or knockdown certain differentially expressed TFs. Furthermore, comparative secretome analyses were conducted to investigate the proteins secreted by co-cultured microfat; changes in gene expression of HSFs were examined after the administration of the potential anti-fibrotic protein. Finally, the relationship between the key TF in HSFs and the microfat-secreted anti-fibrotic adipokine was analyzed.
The anti-fibrotic effect of microfat was confirmed by in vivo transplanted hypertrophic scar models, as the number of α-SMA-positive myofibroblasts was decreased and the expression of fibrosis-related genes downregulated. Co-cultured microfat suppressed the extracellular matrix production of HSFs in in vitro experiment, and the transcription factor ETV4 was primarily differentially expressed in HSFs when compared with normal skin fibroblasts. Overexpression of ETV4 significantly decreased the expression of fibrosis-related genes in HSFs at both mRNA and protein levels. Fetuin-A secreted by microfat could also downregulate the expression of fibrosis-related genes in HSFs, partially through upregulating ETV4 expression.
Our results demonstrated that transcription factor ETV4 is essential for the anti-fibrotic effect of microfat on hypertrophic scars, and that fetuin-A secreted by microfat could suppress the fibrotic characteristic of HSFs through upregulating ETV4 expression. Microfat wields an alleviative influence over hypertrophic scars via fetuin-A/ETV4 axis.

BACKGROUND: Severe atrophic acne scars (AAS) remain the \"Achilles\'s heel\" of AAS treatment. The combination of microfat and subcision treatment is a potential solution for severe AAS.
OBJECTIVE: This study aimed to evaluate the efficacy and safety of combined microfat and subcision treatment for severe (Grade 4) AAS.
METHODS: Data of patients with Grade 4 AAS who underwent combined microfat and subcision treatment between September 2016 and December 2020 were reviewed. Post-treatment evaluation was performed at least 3 months postoperatively. The severity of AAS was graded based on Goodman\'s qualitative classification. The volume of concavities was measured using an Antera 3D camera. Complications were documented.
RESULTS: A total of 42 patients received a single treatment session. Excellent response was observed in 5 (11.9%) patients, very good in 13 (31.0%), good in 22 (52.4%), and poor response in 2 (4.7%). The average reduction of the total volume of concavities was 28.0%. The most common minor side effects were mild swelling and bruising. No major complications were observed.
CONCLUSIONS: Combined microfat and subcision treatment is a safe and effective treatment for severe AAS. The approach will be a significant treatment for severe AAS.