Pro-regenerative lipid mediator 1 (PreM1) is a specialized pro-resolving lipid mediator that promotes wound healing and regenerative functions of mesenchymal stem cells (MSCs), endothelial cells, and macrophages. The healing of third-degree (3°) burns and regenerative functions of MSCs are enhanced by ACgel1, an arginine-and-chitosan-based protein-mimic hybrid hydrogel. Adipose-tissue derived microvascular fragments (MVFs) are native vascularization units and a rich source of MSCs, endothelial cells, and perivascular cells for tissue regeneration. Here we describe an innovative PreM1-MVFs-ACgel1 construct that incorporated PreM1 and MVFs into ACgel1 via optimal design and fabrication. This construct delivered PreM1 to 3°-burn wounds at least up to 7 days-post-burn (dpb), and scaffolded and delivered MVFs. PreM1-MVFs-ACgel1 promoted the healing of 3°-burns in mice, including vascularization and collagen formation. The re-epithelization and closure of 3° burn wounds were promoted by ACgel1, MVFs, PreM1, MVFs-ACgel1, PreM1-ACgel1, or PreM1-MVFs-ACgel1 at certain time-point(s), while PreM1-MVFs-ACgel1 was most effective with 97% closure and 4.69% relative epithelial gap at 13 dpb compared to saline control. The PreM1-ACgel1 and MVFs-ACgel1 also promoted blood vessel regeneration of 3°-burns although PreM1-MVFs-ACgel1 is significantly more effective. These PreM1- and/or MVF-functionalized ACgel1 have nonexistent or minimal graft-donor requirements and are promising adjuvant therapeutic candidates for treating deep burns.
Keywords: 14S,21R-dihydroxy-docosa-4Z,7Z,10Z,12E,16Z, 19Z-hexaenoic acid, or 14S,21R-diHDHA; 3° burn: third-degree burn; AA-PEA: amino acid-based poly(ester amide) polymer; ACgel1, UArg-PEA/Chitosan covalently coupled hydrogel 1; MVFs: microvascular fragments; PreM1-MVFs-ACgel1: PreM1-incorporated and MVFs-seeded ACgel1; PreM1: pro-regenerative lipid mediator 1; UArg-PEA: unsaturated arginine-based poly(ester amide); blood vessel regeneration or vascularization; collagen; wound healing.