Remodeling-phase wound-derived protein factors enhance mesenchymal stem cell function and improve diabetic wound healing.

BACKGROUND: Chronic diabetic wounds result from dysregulated inflammatory responses and impaired progression from the inflammatory to proliferative and remodeling phases of healing. Although mesenchymal stem cells (MSCs) possess regenerative and paracrine potential, their function is compromised within the diabetic wound microenvironment. This study aimed to enhance wound healing by transplanting MSCs conditioned with remodeling-phase wound-derived factors. METHODS: In this preclinical study, bone marrow-derived MSCs were isolated and characterized. Wound extracts from normal and streptozotocin-induced diabetic rats were evaluated, and the non-cytotoxic concentration (10 µg/mL) was used for conditioning. Functional assessment included in vitro scratch assays, gene expression analysis of inflammatory and regenerative mediators, and transplantation in a diabetic wound model, histological (H&E) and immunofluorescence (α-SMA) analyses. RESULTS: Normal Day 9 wound extract (N9)-conditioned MSCs demonstrated enhanced wound closure in vitro. In contrast, Diabetic Day 9 wound extract (D9)-conditioned MSCs exhibited elevated expression of inflammatory genes and reduced expression of angiogenic and proliferative markers. In vivo, N9-conditioned MSCs significantly accelerated wound closure, restored tissue architecture, improved collagen organization, and increased the number of α-SMA-positive vascular structures, supporting enhanced vascular remodeling. CONCLUSION: Conditioning MSCs with remodeling-phase-derived factors present in normal Day 9 wound extract (N9) increases their therapeutic efficacy in diabetic wound healing. This preclinical strategy supports the use of phase-specific wound cues to optimize stem cell-based therapy and facilitate transition toward tissue regeneration.