On July 1, 2021, the American medical website Medicane Net officially announced: after the age of 25, people will continue to show signs of skin aging, and the collagen produced by skin cells will gradually decrease, causing the skin to begin to lose its elasticity and slowly aging.
As the age increases, the rate of wound healing decreases. Why is this happening? Tracing the roots is because with the increase of age, cells also gradually aging, cell regeneration ability declines, so there will be skin aging and wounds are difficult to heal. For these reasons, more and more scholars are focusing on the role of stem cells in the field of anti-cellular aging and skin cell regeneration. Among them, the most studied is mesenchymal stem cells.
Recently, a review published in the International Journal of Molecular Sciences summarized the effects of mesenchymal stem cells on skin cell regeneration and anti-cellular senescence[1]: Mesenchymal stem cells have healing power and can be applied to damaged and aging skin. In skin regeneration, cell proliferation and new blood vessel formation are increased, and inflammation in lesions of skin lesions is reduced. In terms of skin rejuvenation, it promotes the production of collagen and elastin fibers, inhibits the activation of metalloproteinases, and promotes protection against UV radiation-induced aging.
Mesenchymal stem cells promote skin wound healing
Skin wound healing requires four stages: hemostasis (coagulation), inflammation (monocyte infiltration), proliferation (epithelial formation, fibrous proliferation, angiogenesis), and maturation (collagen deposition, scar tissue formation).
Studies have confirmed that even under optimal healing conditions, skin wound repair in adults is imperfect, with delayed wound healing and scarring often occurring. With the aging of the population and the increase in the number of diabetic people, wound healing disorders have gradually become one of the major problems in global healthcare.
Image courtesy of DOI https://doi.org/10.2147/CCID.S331044
The study found [1]: Mesenchymal stem cells play an important role in all processes of wound healing. Mesenchymal stem cells promote cell migration, angiogenesis, epithelialization and granulation tissue formation, thereby accelerating wound closure. In addition, mesenchymal stem cells help reduce scarring by promoting cell regeneration to repair wounds rather than forming fibrous tissue.
A 2009 randomized clinical study found [3] that cultured autologous mesenchymal stem cells were administered topically to 41 patients with diabetic critical limb ischemia and foot ulcers, mainly by intramuscular injection into the affected limb. The results showed that the wound size could be significantly reduced. Also, over the course of 24 weeks of follow-up, patients were much less likely to have amputations than those who had the same degree of illness but had not received stem cell therapy.
Therefore, studies believe that mesenchymal stem cells help promote skin wound healing and also reduce the formation of scars.
Mesenchymal stem cells improve skin aging
The reason why the skin is aging is caused by the loss of function of skin cells and the degradation of structure. As we age, the skin gradually loses collagen and the elasticity of the skin decreases. Mesenchymal stem cells, on the other hand, are of interest in the treatment of skin anti-aging due to their possession of epithelial regenesis and the secretion of growth factors needed for skin regeneration [1].
The researchers [4] observed the changes in the histology and structure of the aging facial skin after the injection of mesenchymal stem cells, and found that the superficial elastin fibers of the dermis increased, the collagen content increased, and the reticular fiber network became more orderly, thereby achieving anti-aging purposes.
Another way to use mesenchymal stem cells in anti-aging treatments is to use extracellular vesicles (EVs), a "cell-free" treatment. Fat-derived mesenchymal stem cell extracellular vesicles have anti-photoaging potential, and the study found that this substance was injected subcutaneously in a photoaging mouse model, and then analyzed, confirming that it can reduce skin wrinkles and promote epidermal cell proliferation. In addition, macrophage infiltration and reactive oxygen species production are reduced, thereby inhibiting the activation of MMP enzyme (an active enzyme that accelerates skin aging and oxidation) and collagen degradation, which plays a role in delaying cellular aging. However, due to the high requirements of this technology, it will take a certain amount of time to be truly applied to the clinic.
In addition to extracellular vesicles, growth factors secreted by stem cells also have the potential to repair the skin. "Expert Consensus on Research and Clinical Trials of Stem Cells in the Field of Plastic Surgery and Repair" emphasizes that the growth factors secreted by stem cells can improve the proliferation ability of the skin to promote the proliferation of fibroblasts in the dermis layer through various active factors, repair aging collagen fibers and elastin fibers, restore skin elasticity and reduce wrinkles by supplementing growth factors in aging skin.
brief summary
Numerous studies have shown the potential of mesenchymal stem cells in the field of skin therapy. Mesenchymal stem cells are considered to be a powerful tool for wound healing and skin rejuvenation, and their associated capabilities make them promising to become effective targets in skin treatment research. In the future, it is still necessary to further carry out more in-depth clinical and basic research to provide strong evidence for the application of stem cells, and at the same time, it is also necessary to strengthen the standardized development and promote the transformation of stem cells in this field.
bibliography:
[1] Jo H, Brito S, Kwak BM, Park S, Lee MG, Bin BH. Applications of Mesenchymal Stem Cells in Skin Regeneration and Rejuvenation. Int J Mol Sci. 2021 Feb 27;22(5):2410.
[2] Hu MS, Borrelli MR, Lorenz HP, Longaker MT, Wan DC. Mesenchymal Stromal Cells and Cutaneous Wound Healing: A Comprehensive Review of the Background, Role, and Therapeutic Potential. Stem Cells Int. 2018 May 20;2018
[3] Lu D, Chen B, Liang Z, Deng W, Jiang Y, Li S, Xu J, Wu Q, Zhang Z, Xie B, Chen S. Comparison of bone marrow mesenchymal stem cells with bone marrow-derived mononuclear cells for treatment of diabetic critical limb ischemia and foot ulcer: a double-blind, randomized, controlled trial. Diabetes Res Clin Pract. 2011 Apr;92(1):26-36.
[4] Charles-de-Sá L, Gontijo-de-Amorim NF, Maeda Takiya C, Borojevic R, Benati D, Bernardi P, Sbarbati A, Rigotti G. Antiaging treatment of the facial skin by fat graft and adipose-derived stem cells. Plast Reconstr Surg. 2015 Apr
[5] Xu P, Xin Y, Zhang Z, Zou X, Xue K, Zhang H, Zhang W, Liu K. Extracellular vesicles from adipose-derived stem cells ameliorate ultraviolet B-induced skin photoaging by attenuating reactive oxygen species production and inflammation. Stem Cell Res Ther. 2020 Jul 1;11(1):264