Acetoacetate-preconditioned adipose stem cells promote burn wound healing through enhanced cellular retention and paracrine signaling.

BACKGROUND: In this study, we preconditioned human adipose-derived stem cells (ADSCs) with acetoacetate (AcAc) and explored whether it could improve cell survival and enhance the tissue regeneration of chemical burns in mice.

METHODS: To evaluate the therapeutic efficacy of AcAc, human ADSCs were preconditioned with 10 mM AcAc (AcAc-hADSCs). Cell proliferation, migration, paracrine release of growth factors, and proangiogenic effects of AcAc-hADSCs were subsequently assessed. Subsequently, HCl acid burns were induced on the dorsal skin of ICR mice, and wound healing progression was monitored through macroscopic examination. The wounds were harvested for histological assessment via staining. Angiogenesis in wounds was detected via immunohistochemical staining. hADSCs were prelabeled with DiO, and their wound survival was detected via an in vivo bioluminescence imaging system.

RESULTS: Pretreatment with AcAc enhanced the migration of ADSCs and the paracrine release of proangiogenic cytokines, including HIF-1α, VEGFA, HGF, FGF-2 and TGF-β, and increased the expression of SOD1. Compared with those treated with control hADSCs, the wounds that received AcAc-hADSCs presented accelerated re-epithelialization, increased extracellular matrix (ECM) deposition, and improved the microvessel density by HIF-1α-VEGFA pathway. Moreover, the DiO-labelled AcAc-hADSCs could be observed even after 72 h; while ADSCs could be only detected at 24 h. In addition, wounds treated with AcAc-hADSCs presented more Ki67 + cells. qRTPCR analysis revealed a significant increase in the expression of proangiogenic factors and a decrease in the levels of IL-1, IL-6 and iNOs in wounds that received AcAc-hADSCs.

CONCLUSION: These findings demonstrate that AcAc preconditioning enhances hADSC persistence in wounds, consequently promoting both re-epithelialization and angiogenesis.