Introduction: Chronic wounds are wounds that stay unhealed for longer than 4 weeks and currently lack effective treatments. The release of growth factors by activated platelets through extracellular vesicles (EVs) has been shown to be pivotal for healthy wound healing. Hence, platelet-derived EVs (pEVs) could represent a next-generation therapeutic for the treatment of chronic wounds. As clinical translation of EV-based therapeutics has been previously hampered by challenges in scalable manufacturing, this study aimed to address these gaps by isolating clinical-grade pEVs using a scalable, proprietary chromatography-based method, evaluating their functional efficacy in cell-based assays and lastly, assessing their safety upon administration in humans in a Phase I clinical trial.
Methods: pEVs were isolated using Exopharm’s Ligand Exosome Affinity Purification and characterized for particle size, count and morphology. In vitro assays were performed to assess functional activity. Lastly, a Phase I Clinical trial in healthy volunteer adults was conducted to assess safety of pEV administration following a skin punch biopsy (n = 11).
Results: Clinical-grade pEVs were found to adhere to MISEV guidelines. pEVs significantly improved cellular functions such as dermal fibroblast proliferation and migration in vitro. Clinically, a single injection of pEVs (300 μg mL-1) was found to be safe and well-tolerated. Mean healing time of 22.8 ± 8.7 days was recorded for both pEV- and placebo- treated groups, with each wound healed within 30 days.
Conclusion: These results demonstrate the feasibility of a pEV-based therapeutic and warrants further studies to assess efficacy in patients with disrupted wound healing.