Engineering MSC-exosomes for diabetic bone regeneration: from mechanism to delivery

The rapidly growing diabetic population is at high risk of dental implant failure due to a disrupted peri-implant immune microenvironment. Mesenchymal stem cells-derived exosomes (MSC-Exos) have emerged as a potent nanotherapeutic platform to remodel this hostile niche. Their mechanisms involve reprogramming macrophage polarization to alleviate inflammation, delivering pro-angiogenic miRNAs to restore vascular-osteogenic coupling, and modulating neuro-immune crosstalk to reestablish homeostasis. Collectively, these actions break the vicious cycle of impaired healing. Furthermore, engineering strategies such as membrane modification, integration with biomaterials, and preconditioning of parent cells can enhance the targeting, stability, and controlled release of MSC-Exos, thereby improving osseointegration outcomes in diabetic models. These engineering innovations, which focus on precise delivery and controlled release, are as critical to therapeutic development as elucidating the underlying biological mechanisms. This review systematically delineates the mechanisms by which MSC-Exos recalibrate the diabetic bone immune niche to foster osseointegration and critically discusses the clinical translation prospects of engineered exosome-based therapies.