Modifying MSCs-derived EVs with esterase-responsive and charge-reversal cationic polymers enhances bone regeneration

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Cell Biology

Background:

• Mesenchymal stem cell-derived extracellular vesicles (EVs) are promising cell-free therapies for bone defects due to stability and biocompatibility.
• Current EV isolation methods are costly and time-consuming, hindering clinical application.
• Enhancing EV uptake and targeted delivery is crucial for effective bone regeneration.

Purpose of the Study:

• To develop a cost-effective method for enhancing bone marrow mesenchymal stem cell-derived EVs (BMSCs-EVs) for bone defect repair.
• To improve the osteogenic potential and selective release of BMSCs-EVs in bone-related cells.
• To evaluate the efficacy of modified EVs in promoting bone regeneration in vivo.

Main Methods:

• Modified BMSCs-EVs (ERP-EVs) by mixing with a cationic polymer (ERP) exhibiting charge reversal and esterase response.
• Assessed ERP-EVs' effect on BMSC osteogenesis and compared EV release in BMSCs versus fibroblasts.
• Loaded ERP-EVs onto an nHA/CS-MS scaffold for in vivo testing in rat calvarial bone defects.

Main Results:

• ERP-EVs significantly enhanced BMSC osteogenesis compared to unmodified EVs.
• ERP demonstrated selective release of EVs in BMSCs, with higher release rates than in fibroblasts.
• ERP-EV loaded scaffolds promoted enhanced bone regeneration in rat calvarial defects.

Conclusions:

• The ERP modification strategy effectively improves cellular uptake and selective release of BMSCs-EVs in bone cells.
• ERP-EVs show significant potential for enhancing bone regeneration in defect models.
• This approach offers a viable strategy to accelerate the clinical translation of BMSCs-EVs for bone defect repair.