Thermos-responsive hydrogel system encapsulated engineered exosomes attenuate inflammation and oxidative damage in acute spinal cord injury

Release of exosomes from injectable silk fibroin and alginate composite hydrogel for treatment of myocardial infarction

Myocardial infarction (MI) is considered as a significant cause of death globally. Exosomes (EXOs) are essential for intercellular communication and pathophysiology of several cardiovascular diseases. Nevertheless, the short half-life and rapid clearance of EXOs leads to a lack of therapeutic doses delivered to the lesioned area. Therefore, an injectable silk fibroin and alginate (SF/Alg) composite hydrogel was developed to bind folate receptor-targeted EXOs (FA-EXOs) derived from H9C2 cells for the therapy of myocardial injury following myocardial infarction-ischemia/reperfusion (MI-I/R). The resulting composite exhibits a variety of properties, including adjustable gelation kinetics, shear-thinning injectability, soft and dynamic stability that adapts to the heartbeat, and outstanding cytocompatibility. After injected into the damaged rat heart, administration of SF/Alg + FA-EXOs significantly enhanced cardiac function as demonstrated by improved ejection fraction, fractional shortening and decreased fibrosis area. The results of real-time PCR and immunofluorescence staining show a remarkable up-regulation in the expression of proteins (CD31) and genes (VWF and Serca2a) related to the heart. Conversely, expression of fibrosis-related genes (TGF-β1) decreased significantly. Therefore, the obtained SF/Alg + FA-EXOs system remarkably enhanced the intercellular interactions, promoted cell proliferation and angiogenesis, and achieved an outstanding therapeutic effect on MI.

Beyond Traditional Medicine: EVs-Loaded Hydrogels as a Game Changer in Disease Therapeutics

Extracellular vesicles (EVs), especially exosomes, have shown great therapeutic potential in the treatment of diseases, as they can target cells or tissues. However, the therapeutic effect of EVs is limited due to the susceptibility of EVs to immune system clearance during transport in vivo. Hydrogels have become an ideal delivery platform for EVs due to their good biocompatibility and porous structure. This article reviews the preparation and application of EVs-loaded hydrogels as a cell-free therapy strategy in the treatment of diseases. The article also discusses the challenges and future outlook of EVs-loaded hydrogels.

Hydrogel-encapsulated extracellular vesicles for the regeneration of spinal cord injury

Spinal cord injury (SCI) is a critical neurological condition that may impair motor, sensory, and autonomous functions. At the cellular level, inflammation, impairment of axonal regeneration, and neuronal death are responsible for SCI-related complications. Regarding the high mortality and morbidity rates associated with SCI, there is a need for effective treatment. Despite advances in SCI repair, an optimal treatment for complete recovery after SCI has not been found so far. Therefore, an effective strategy is needed to promote neuronal regeneration and repair after SCI. In recent years, regenerative treatments have become a potential option for achieving improved functional recovery after SCI by promoting the growth of new neurons, protecting surviving neurons, and preventing additional damage to the spinal cord. Transplantation of cells and cells-derived extracellular vesicles (EVs) can be effective for SCI recovery. However, there are some limitations and challenges related to cell-based strategies. Ethical concerns and limited efficacy due to the low survival rate, immune rejection, and tumor formation are limitations of cell-based therapies. Using EVs is a helpful strategy to overcome these limitations. It should be considered that short half-life, poor accumulation, rapid clearance, and difficulty in targeting specific tissues are limitations of EVs-based therapies. Hydrogel-encapsulated exosomes have overcome these limitations by enhancing the efficacy of exosomes through maintaining their bioactivity, protecting EVs from rapid clearance, and facilitating the sustained release of EVs at the target site. These hydrogel-encapsulated EVs can promote neuroregeneration through improving functional recovery, reducing inflammation, and enhancing neuronal regeneration after SCI. This review aims to provide an overview of the current research status, challenges, and future clinical opportunities of hydrogel-encapsulated EVs in the treatment of SCI.