Next-Generation Theranostic Tools for Bone Repair and Skeletal Metabolism with Exosomes

The advanced progress in the avenues of translational medicine for bone repair utilizes the development of targeted drug delivery therapy along with diagnosing the pathobiology of a disease process. Extracellular vesicles, especially exosomes which are cell derived molecules in size range of 30–150 nm in diameter, are now being recognized as a key player for maintaining the homeostasis of individuals by intracellular communication through their enriched cargo. Their cargo consists of DNA, miRNA, lipids, proteins, and mRNAs reflecting the functionality of the host cells. Thus, by delivering these cargos, they modify the gene expression and modulate the signaling cascade in the recipient cells leading to migration, differentiation, activation, apoptosis etc. providing therapeutic advantages. They possess an immense potential to actively deliver drugs to recipient cells owing to their superior biocompatibility, low immunogenicity, specificity, and good payload capability in contrast to synthesized polymeric nanoparticles or carriers. Besides that, they consist of many protein biomarkers related to a specific disease and are reported to be found in body fluids such as plasma, milk, saliva, amniotic fluid, and urine, thus they can act as prospective early-stage disease diagnostic tools. Specifically, in the case of bone diseases and skeletal metabolism, the diagnosis involves expensive techniques like bone biopsy and imaging after progression of disease. Accordingly, this chapter examines the state-of-the-art in exosomal research for bone regeneration and diagnostic strategies for bone diseases.