Exosomes as a Treatment for Skin Aging
Much of the communication that takes place between cells takes the form of secretion and uptake of extracellular vesicles, small membrane-wrapped packages of diverse molecules. Vesicles are currently categorized by size, for lack of a better taxonomy, and exosomes are one of the better studied size classes. It appears to be the case that much of the benefit of first generation stem cell therapies is produced by the signaling generated by transplanted cells, and thus the research community has started to focus on the logistically easier approach of harvesting and using extracellular vesicles rather than transplanting the cells themselves. While extracellular vesicle therapies are readily available via medical tourism, widespread use in the more regulated end of the medical community remains a work in progress.
Photoaging is a prominent manifestation of skin aging characterized by the appearance of mottled pigmentation, fine lines, and wrinkles. The main molecular mechanisms of photoaging are accumulation of reactive oxygen species, cellular senescence, inflammation, and collagen degradation. Targeting these pathways through novel therapeutics is an intriguing area of study in regenerative medicine.
Exosomes are tiny extracellular vesicles secreted by most cell types, which are filled with proteins, lipids, and nucleic acids (non-coding RNAs, mRNA, DNA), can be released by donor cells to subsequently modulate the function of recipient cells. Exosomes are able to regulate multiple cellular processes due to their important role in cellular communication.
In recent years, exosomes have emerged as a novel therapeutic option for treatment of many diseases. This review aims to summarize the current findings on the roles of exosomes, particularly those derived from stem cells, in the context of skin photoaging. In preclinical studies, stem cell-derived exosomes can restore skin physiological function and regenerate or rejuvenate damaged skin tissue through various mechanisms such as decreased expression of matrix metalloproteinase (MMP), increased collagen and elastin production, and modulation of intracellular signaling pathways as well as, intercellular communication. All these evidences are promising for the therapeutic potential of exosomes in skin photoaging.