Bioactive silica-based nanoparticles stimulate bone-forming osteoblasts, suppress bone-resorbing osteoclasts, and enhance bone mineral density in vivo

Abstract Bone is a dynamic tissue that undergoes renewal throughout life in a process whereby osteoclasts resorb worn bone and osteoblasts synthesize new bone. Imbalances in bone turnover lead to bone loss and development of osteoporosis and ultimately fracture, a debilitating condition with high morbidity and mortality. Silica is a ubiquitous biocontaminant that is considered to have high biocompatibility. The authors report that silica nanoparticles (NPs) mediate potent inhibitory effects on osteoclasts and stimulatory effects on osteoblasts in vitro. The mechanism of bioactivity is a consequence of an intrinsic capacity to antagonize activation of NF-κB, a signal transduction pathway required for osteoclastic bone resorption but inhibitory to osteoblastic bone formation. We further demonstrate that silica NPs promote a significant enhancement of bone mineral density (BMD) in mice in vivo, providing a proof of principle for the potential application of silica NPs as a pharmacological agent to enhance BMD and protect against bone fracture. From the Clinical Editor In this paper, silicate nanoparticles are utilized in an animal model to stimulate bone growth by inhibiting osteoclasts while enhancing the activity of osteoblasts. This result may have important ramification in future applications to a variety of bone diseases, including but not limited to osteoporosis, pathological fractures, metastatic bone lesions, different types of bone cancer, etc.