Topical application of a hyaluronic acid-based hydrogel integrated with secretome of human mesenchymal stromal cells for diabetic ulcer repair

This preclinical proof-of-concept study aimed to evaluate the effectiveness of secretome therapy in diabetic mice with pressure ulcers. We utilized a custom-made hyaluronic acid (HA)-based porous sponge, which was rehydrated either with normal culture medium or secretome derived from human mesenchymal stromal cells (MSCs) to achieve a hydrogel consistency. Following application onto skin ulcers, both the hydrogel-only and the hydrogel + secretome combination accelerated wound closure compared to the vehicle group. Notably, the presence of secretome significantly enhanced the healing effect of the hydrogel, as evidenced by a thicker epidermis and increased revascularization of the healed area compared to the vehicle group. Notably, molecular analysis of healed skin revealed significant downregulation of genes involved in delayed wound healing and abnormal inflammatory response in ulcers treated with the hydrogel + secretome combination, compared to those treated with the hydrogel only. Additionally, we found no significant differences in therapeutic outcomes when comparing the use of secretome from fetal dermal MSCs to that from umbilical cord MSCs. This observation is supported by the proteomic profile of the two secretomes, which suggests a shared molecular signature responsible of the observed therapeutic effects.