Lipoaspirate-derived secretome activates NRF2 to restore redox homeostasis and attenuate pathological scar formation

Background : Pathological scars are characterized by persistent fibroblast activation and excessive extracellular matrix (ECM) deposition. Although oxidative stress and dysregulated NRF2 signaling drive TGF-β1–mediated fibrosis in internal organs, their roles in cutaneous pathological scarring remain unclear. Adipose-derived stromal cell (ADSC) and lipoaspirate-derived extracellular vesicles (EVs) can promote wound repair and reduce fibrosis, but whether their bioactive components restore fibroblast redox homeostasis via NRF2 to mitigate cutaneous pathological scarring is unknown. Methods : Lipoaspirate fluid obtained during standard tumescent liposuction was processed by 100 kDa ultrafiltration to generate a lipoaspirate-derived secretome (LA). Secretome from adipose-derived stromal cell (ADSC) culture supernatant served as a comparator (CS). LA and CS were characterized by nanoparticle tracking analysis, transmission electron microscopy, and EV-associated marker immunoblotting. In vivo efficacy was evaluated in a rabbit ear pathological scar model with weekly intradermal LA injections, assessed by gross imaging, histology/collagen staining, and qPCR. LA versus CS proteomics (DIA LC–MS/MS) with enrichment analysis and single-cell RNA sequencing of paired scar/normal skin were performed. In vitro, TGF-β1–stimulated fibroblasts were treated with LA or CS ± ML385. Redox balance, NRF2 signaling, and profibrotic responses were assessed by fluorometric assays, qPCR, and immunoblotting. Results: LA showed a substantially higher particle yield than CS and was enriched in extracellular vesicles. Weekly intradermal LA injections reduced scar hypertrophy and improved collagen organization in the rabbit ear model. Proteomics (LA vs CS) highlighted cytoprotective pathways, including glutathione metabolism and NRF2-associated antioxidant signaling. scRNA-seq of paired human scar/normal skin samples showed NOX4 upregulation with reduced NRF2 signaling in scar fibroblasts. In vitro, LA (vs CS) attenuated TGF-β1–driven oxidative stress and profibrotic activation, improved GSH/GSSG balance, and suppressed NOX4 and ECM genes; ML385 abrogated these effects. Conclusion : LA is a clinically accessible, EV-enriched acellular therapy that corrects the redox–fibrotic imbalance of pathological scarring by activating NRF2 signaling, suppressing NOX4-linked oxidative stress, and attenuating TGF-β1–driven fibroblast profibrotic activation, thereby improving scar remodeling in vivo. Single-cell transcriptomics identified elevated NOX4 and impaired NRF2 signaling in scar fibroblasts, supporting this mechanism and suggesting LA as a scalable, autologous option for targeting oxidative stress and fibrosis.