Introduction: Extracellular vesicles known as exosomes, which are small and enclosed by a membrane, have crucial roles in communication between cells. They range in size from 30 to 150 nanometers and are created by the inward budding of late endosomes, also called multivesicular bodies (MVBs). Upon MVBs fusing with the plasma membrane, they release exosomes, which are intraluminal vesicles, into the extracellular space. Exosomes have diverse functions in both health and disease, including intercellular communication, serving as biomarkers, delivering drugs, and modulating the immune system. The molecules serve as intermediaries in communication between cells, impacting different biological functions like immune response, transmission of signals, and presentation of antigens. Exosomes can act as biomarkers for diseases such as cancer, neurodegenerative disorders, and cardiovascular diseases by containing specific profiles of proteins and nucleic acids. They also offer information about the cellular origin and state of the donor cells. Exosomes are currently under investigation as natural carriers of drugs because they can package therapeutic substances and pinpoint particular cells or tissues while having minimal potential to provoke an immune response. They have the capability to traverse biological barriers, like the blood-brain barrier, thus improving the effectiveness of treatments. In addition, exosomes have the ability to influence immune reactions, which is advantageous in situations such as autoimmune disorders and when the body is repairing tissues.
Methods: Exosomes have become a focal point in the field of bone tissue engineering due to their ability to facilitate cell-to-cell communication and stimulate the regeneration of bone. These extremely small vesicles, produced by a variety of cell types, especially Adipose-Derived Stem Cells (ADSCs) and Bone Marrow-Derived Mesenchymal Stem Cells, contain a wide range of essential biomolecules such as proteins, lipids, and RNAs, which play a critical role in regulating cellular functions and improving the formation of bone tissue. The roles of exosomes in bone repair are diverse, with a focus on their mechanisms of action, which include stimulating the proliferation, differentiation, and recruitment of MSCs to injury sites. Additionally, there is growing interest in the modification of exosomes to improve their therapeutic effectiveness, such as altering their cargo and utilizing advanced biomaterials to optimize their delivery and sustained release at bone defect sites.
Results: Engineered exosomes have shown a significantly enhanced ability to promote osteogenesis, which is the process of bone formation. These specialized vesicles play a crucial role in facilitating both the proliferation and differentiation of osteoblasts, the cells responsible for bone formation. By promoting the growth and maturation of osteoblasts, engineered exosomes contribute to the overall development and repair of bone tissue. Engineered exosomes also improve the recruitment of MSCs to areas where there is a deficiency in bone. Methods like electroporation and transfection are employed to introduce targeted therapeutic agents into exosomes, thereby enhancing their regenerative potential. Despite the advancements that have been achieved in recent years, a number of significant challenges continue to hinder further development and optimization in the field. One of the primary issues is irregular production, which can lead to inconsistencies in supply and affect overall efficiency. Additionally, suboptimal extraction rates remain a concern, as they can limit the yield of valuable resources and impact the economic viability of operations. Furthermore, the mechanisms of action involved in the processes are often ambiguous, leading to uncertainties that complicate efforts to improve methodologies and outcomes. Addressing these challenges is crucial for ensuring sustained progress and maximizing the potential benefits of the advancements made thus far. Current research endeavors focus on enhancing exosome engineering and the integration of biomaterials to address existing challenges and improve their utilization in clinical environments. The integration of engineered exosomes with cutting-edge biomaterials presents significant opportunities for synergistic outcomes in bone regeneration, thereby facilitating the development of novel therapeutic strategies in the field of regenerative medicine.
Conclusion: Although exosomes hold significant potential for applications in bone tissue engineering, several challenges persist in the transition of exosome-based therapies from laboratory research to clinical practice. These challenges encompass concerns regarding the consistency of production, precision in targeting, and the necessity for efficient delivery mechanisms.
Keywords: Engineered Exosomes, Regenerative Medicine, MSCs, Bone Tissue Engineering, Biomaterials