Human adipose-derived mesenchymal stem cells-derived exosomes encapsulated in pluronic F127 hydrogel promote wound healing and regeneration

Abstract

Background Large area skin trauma has always been a great challenge for both patients and clinicians. Exosomes originating from human adipose-derived mesenchymal stem cells (hADSCs) have been a novel promising cell-free treatment in cutaneous damage repair. Nevertheless, the low retention rate of exosomes post-transplantation in vivo remains a significant challenge in clinical applications. Herein, we purposed to explore the potential clinical application roles of hADSCs-Exos encapsulated in functional PF-127 hydrogel in wound healing. Methods hADSCs-Exos were isolated from human hADSCs by ultracentrifugation. An injectable, biocompatible, and thermo-sensitive hydrogel Pluronic F-127 hydrogel was employed to encapsulate allogeneic hADSCs-Exos, and this complex was topically applied to a full-thickness cutaneous wound in mice. On different days post-transplantation, the mice were sacrificed, and the skin tissue was excised for histological and immunohistochemical analysis. Results Compared with hADSCs-Exos or PF-127 only, PF-127/hADSCs-Exos complexes enhanced skin wound healing, promoted re-epithelialization, increased expression of Ki67, α-SMA, and CD31, facilitated collagen synthesis (Collagen I, Collagen III), up-regulated expression of skin barrier proteins (KRT1, AQP3), and reduced inflammation (IL-6, TNF-α, CD68, CD206). By using PF-127/hADSCs-Exos complexes, hADSCs-Exos can be administrated at lower doses frequency while maintaining the same therapeutic effects. Conclusion Administration of hADSCs-Exos in PF-127 improves the efficiency of exosome delivery, maintains the bioactivity of hADSCs-Exos, and optimizes the performance of hADSCs-Exos. Thus, this biomaterial-based exosome will be a promising treatment approach for the cutaneous rejuvenation of skin wounds.

Extracellular vesicle-loaded hydrogels for tissue repair and regeneration

“…The release of EVs from hydrogels is often characterized using a micro bicinchoninic acid (BCA) assay, ELISA, or fluorescent labeling. The BCA assay can be used to determine the percentage of released EVs by mixing the EVs with the hydrogel, placing the mixture in the upper chamber of a 24-well transwell plate, and measuring the protein concentration in the lower chamber at different time points [ 167 ]. Similarly, a dynamic dialysis method can be used to detect the release of EVs by placing the EV-loaded hydrogel in a dialysis bag and placing the bag in a constant-temperature phosphate buffered saline (PBS) solution.…”

“…By placing a hydrogel loaded with PKH26-labeled EVs in a 24-well plate filled with PBS, the EV release rate can be calculated by measuring PKH26 fluorescence in the supernatant over time [ 72 ]. In in vivo experiments, hydrogels loaded with PKH26-labeled EVs were applied to traumatic wound surfaces and the release rate was calculated by measuring the fluorescence intensity of PKH26 in tissues at different time periods [ 72 , 167 ]. Likewise, experiments in which EVs were labeled with DiI showed that DiI-labeled EVs were gradually released from hydrogels with increasing incubation time ( Fig.…”

“… [ 126 ] PF-127 ADSC 30–100 ​nm 96 ​h PF-127 concentration affects the release of EVs. [ 167 ] 4-arm-PEG-MAL ADSC / 20 days The degradation rate of hydrogels can be controlled to regulate the release of EVs. [ 168 ] Chitosan-Collagen BMSC 131.3 ​± ​11.4 ​nm 7 days The release of EVs from these hydrogel formulations was dependent on chitosan/collagen ratios.…”

“…Zhou et al. [ 167 ] combined PF-127 hydrogel with human ADSC-Exosomes (hADSC-Exos) and found that it prolonged the release of hADSC-Exos up to 72 ​h, leading to the enhancement of cell proliferation, angiogenesis, collagen remodeling, and re-epithelialization of the wound site and ultimately accelerating the wound healing process. In addition, the self-healing hydrogel provided durable protection against bacterial or foreign body irritation, maintained the biological activity of the EVs, and significantly promoted wound repair.…”

“… Tissue/organ to be regenerated Hydrogel Sources of EVs Application strategies Key findings Reference Skin/Wound healing PF-127 ADSC Topical administration PF-127 hydrogel-loaded EVs can effectively promote wound healing. [ 167 ] MMP-PEG smart hydrogel ADSC Topical administration It can target the MMP2 response and significantly promote the recovery of diabetic wounds. [ 168 ] HAMA Microneedle MSC-EVM Microneedle (MN) MN patches containing EVs show the ability to deliver deep into the skin.…”