Cutaneous wound healing is a complex but highly efficient process. Under
certain pathologic conditions healing may be impaired, thus lengthening
the process and eventually leading to repeated medical intervention and
wound chronicity. Exosomes (secreted extracellular vesicles) are present
in biological fluids where they exert a key role in intercellular communication at the tissue, organ and organismal levels. Since human breast milk presents abundant maternal extracellular vesicles (hMEVs) with immunomodulatory and pro-regenerative properties, in the present study we aimed to evaluate if topical application of hMEVs into open wounds would be beneficial for healing. Excision full-thickness skin wounds of 4-mm diameter were generated in the dorsal skin of C57BL/6 mice, and 20 μg human MEVs isolated at breastfeeding weeks 9, 11, 12 and 15 postpartum were topically placed onto the wounds. Control wounds were vehicle-treated. Macroscopic measurements up to 7 days post-wounding revealed that MEV-treated wound area decreased significantly more rapidly as compared with controls. Histological analyses at day 7 post-wounding showed no differences between groups in the granulation tissue area. However, dermal integrity of the wounds appeared to vary under MEV treatments isolated at different breastfeeding weeks. Our preliminary results suggest that MEV treatment at certain breastfeeding weeks may induce faster wound closure but also granulation tissue aberration.

Topical use of exosomes from human maternal milk accelerates acute cutaneous wound healing