Potential Effects of Exosomes and their MicroRNA Carrier on Osteoporosis

Osteoporosis is a common localized or systemic skeletal illness in the clinic, characterized by bone production weakness and increased bone resorption, resulting in a reduction in bone mineral density (BMD), and affecting mostly postmenopausal women. The risk of osteoporosis or even osteoporotic fracture increases as age increases, putting more pressure on society and families. Although anti-osteoporosis drugs have been developed, some side effects are still observed in the treatment group. Hence the need for more reasonable therapeutic strategies. Exosomes are nanosized extracellular vesicles (EVs) secreted virtually by all types of cells in vivo, which play an important role in intercellular communication. Compared with conventional drugs and stem cells transplantation therapy, exosomes have apparent advantages of lower toxicity and immunogenicity. Exosomes contain many functional molecules, such as proteins, lipids, mRNAs, microRNAs (miRNAs), which can be transferred into recipient cells to regulate a series of signaling pathways and influence physiological and pathological behavior. In this review, we briefly summarize the current knowledge of exosomes and the therapeutic potential of exosomal miRNAs derived from mesenchymal stem cells (MSCs), osteoblasts, osteoclasts, and macrophages in osteoporosis. Finally, a prospect of new treatment strategies for osteoporosis using new biomaterial scaffolds combined with exosomes is also given.