Dual-Functional Nanoparticles to Reverse Osteoblast Senescence and Enhance Calcium Supplementation for Alleviating Senile Osteoporosis.

Senile osteoporosis (SOP) primarily arises from an imbalance between bone formation and bone resorption. The tightly regulated coupling between osteoblasts and osteoclasts limits the therapeutic efficacy of conventional anti-resorptive agents and anabolic agents. Anti-aging therapy offers a potential strategy to modify the senescent phenotype of bone-associated cells, restore cellular function, and re-establish homeostasis between bone resorption and formation. Calcium-based nanoparticles can effectively deliver therapeutic agents to target sites while simultaneously supplying exogenous calcium. Moreover, restored osteoblast function enhances the cellular capacity to process supplemented exogenous calcium ions, ultimately increasing bone density and further alleviating osteoporosis. In this context, a dual-functional calcium carbonate nanoparticle is engineered. This nanoparticle facilitates the complexation of nicotinamide mononucleotide, enabling targeted delivery to osteoblasts, reversing osteoblast senescence, and restoring their osteogenic function. Simultaneously, through calcium supplementation, the nanoparticle promotes osteoblast differentiation and mineralization. In vitro and in vivo studies have demonstrated the promising therapeutic efficacy of this nanoparticle in treating SOP, providing critical insights for the future development of integrated anti-senescence therapies and calcium supplementation strategies.