Bidirectional modulation of glycolysis using a multifunctional nanocomposite hydrogel promotes bone fracture healing in type 2 diabetes mellitus

Fracture healing in patients with type 2 diabetes mellitus (T2D) is markedly impaired, characterized by a prolonged inflammation phase and defective osteoblast differentiation at the fracture site. In this study, we identified aberrant cellular glycolysis at T2D fracture sites, with bone marrow mesenchymal stem cells (BMSCs) exhibiting suppressed glycolysis and macrophages displaying enhanced glycolysis, mediated by the dysregulation of hypoxia-inducible factor-1α (HIF-1α). To rectify these metabolic imbalances, we developed a multifunctional nanocomposite PN@MHV hydrogel. Myricitrin, a flavonoid glycoside, forms the MHV hydrogel by cross-linking with HA-PBA and PVA via hydrogen bonds, and upregulates glycolysis through HIF-1α, thus promoting osteoblast differentiation under high glucose environment. To further regulate the inflammatory microenvironment, we incorporated nanoparticles loaded with PX-478, a HIF-1α specific inhibitor, into the hydrogel, with folic acid covalently modified to target proinflammatory M1 macrophages. This PN@MHV hydrogel bidirectionally regulated glycolysis via HIF-1α, enhancing osteoblast differentiation while attenuating macrophage-mediated inflammation. Comprehensive in vitro and in vivo experiments in a T2D fracture mouse model confirmed the hydrogel's ability to improve the inflammatory microenvironment and accelerate bone healing. Our findings underscore the therapeutic potential of targeting cellular glycolysis as a promising approach for enhancing fracture healing in diabetic patients.