Exosomes in osteoporosis: regulatory mechanisms and clinical applications.

Osteoporosis is a systemic metabolic bone disorder characterized by progressive bone mass reduction and microarchitectural deterioration, leading to fragility fractures. It poses a serious threat to the health of middle-aged and elderly populations and imposes a heavy healthcare burden. Exosomes mediate intercellular communication by transporting bioactive molecules such as proteins, miRNAs, and circRNAs, exerting bidirectional regulation on bone homeostasis. Exosomes derived from mesenchymal stem cells, young plasma, and plants often improve osteoporosis by promoting osteoblastic differentiation and suppressing osteoclastic activity. Conversely, exosomes originating from osteoclasts, M1 macrophages, and tumor cells tend to accelerate bone resorption. Exosomes not only provide highly specific non-invasive biomarkers for osteoporosis but also emerge as novel therapeutic carriers due to their inherent biocompatibility, targeted delivery properties, and potential for engineered modification. This systematic review examines the biological properties of exosomes, the molecular mechanisms by which exosomes from different sources regulate bone metabolism, and their application progress in the diagnosis and treatment of osteoporosis. It also explores challenges in their clinical translation, providing a comprehensive reference for further research and clinical application in this field.