Role of Extracellular Vesicles in Skin Barrier Repair: Applications in Atopic Dermatitis and Chronic Wounds

Extracellular vesicles (EVs) have emerged as a promising cell-free therapeutic strategy for skin barrier repair due to their ability to mediate intercellular communication through the delivery of bioactive cargo including proteins, lipids, and nucleic acids. This review synthesises current evidence on the role of EVs in restoring skin barrier integrity, with a particular focus on atopic dermatitis (AD) and chronic wounds. EVs derived from mesenchymal stromal cells, epidermal cells, and commensal microbiota exhibit distinct but overlapping therapeutic properties, including immunomodulation, promotion of keratinocyte proliferation and differentiation, and stimulation of dermal remodelling and angiogenesis. These effects are mediated through key signalling pathways such as AKT, ERK, NF-κB, Wnt/β-catenin, and HIF-1α/VEGF, as well as through regulatory microRNAs that fine tune cellular responses. Importantly, the relative contribution of these mechanisms is context dependent, with immune modulation predominating in AD and angiogenesis and tissue regeneration playing a central role in chronic wound healing. Despite strong preclinical evidence demonstrating efficacy, translation into clinical application remains limited by challenges in delivery, standardisation, and scalability. This review highlights the therapeutic potential of EV while emphasising the need for improved delivery strategies and rigorously designed clinical studies to fully realise their clinical utility in skin barrier repair.