Amir Bajouri - MD, Hair and Stem Cells Department Director, Skin and Stem Cells Research Center, TUMS, Tehran, Iran

Exosomes are small extracellular vesicles that are released by various cells, including stem cells, and they contain a variety of bioactive molecules such as proteins, lipids, and nucleic acids. These exosomes have been found to play a crucial role in intercellular communication and tissue repair. Mesenchymal stem cells (MSCs) are a type of multipotent stem cells with the potential to differentiate into a variety of cell types. They have gained attention for their regenerative properties and ability to modulate the immune system. MSCs release exosomes, small membrane-bound vesicles containing proteins, lipids, and nucleic acids, which play a role in cell-to-cell communication. Studies have shown that MSC-derived exosomes can significantly accelerate the healing process of various types of wounds, including diabetic ulcers, burns, and surgical incisions through enhancing collagen deposition, promoting the migration and proliferation of keratinocytes and fibroblasts, and improve the quality of healed tissue. Exosomes promote cell proliferation and migration by delivering growth factors, cytokines, and microRNAs to the target cells. They also stimulate angiogenesis by transferring pro-angiogenic factors to endothelial cells, leading to the formation of new blood vessels. Furthermore, exosomes modulate the extracellular matrix by regulating the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases, facilitating tissue remodeling and wound closure. Additionally, exosomes exhibit anti-inflammatory effects by suppressing pro-inflammatory cytokines and promoting the secretion of anti-inflammatory cytokines, thereby controlling the inflammatory response at the wound site. This intricate molecular interplay orchestrated by exosomes ultimately accelerates wound healing and mitigates scar formation.