Mesenchymal stem cells (MSCs), a kind of multipotent stem cells with self-renewal ability and multi-differentiation ability, have become the “practical stem cells” for the treatment of diseases. MSCs have immunomodulatory properties and can be used to treat autoimmune diseases, and aging. At present, many clinical experiments are using MSCs. MSCs can reduce the occurrence of inflammation and apoptosis of tissue cells, and promote the proliferation of endogenous tissue and organ cells, so as to achieve the effect of repairing tissue and organs. MSCs presumably also play an important role in Corona Virus Disease 2019 (COVID-19) infection.
MSCs can differentiate into a variety of tissue cells derived from mesoderm and neuroectoderm, such as osteoblasts, chondrocytes, adipocytes, tenocytes, smooth muscle cells, bone marrow stromal cells, fibroblasts and a variety of vascular endothelial cells, and even neurons and glial cells of the nervous system. Moreover, proteins secreted by MSCs have anti-microbial, anti-fibrotic, and regenerative effects, and have effects on cell proliferation, differentiation, immune regulation, angiogenesis, wound healing, and tissue regeneration. Therefore, MSCs have become the “practical stem cells” for the treatment of multiple systemic diseases. Moreover, MSCs have a unique function of secreting cytokines. The active proteins secreted by MSCs have played an important role in tissue healing. For example, they can construct collateral circulation, alleviate ischemic symptoms, inhibit inflammation, regulate immunity, maintain the local microenvironment homeostasis of ulcer wounds, and, most importantly, activate and recruit autologous stem cells for repair.
Application of MSCs in COVID-19
The Corona Virus Disease 2019 (COVID-19) has swept the world, and more and more people are infected with the virus. Therefore, the treatment of patients has become the direction of many scientists. COVID-19 is characterized by pneumonia, lymphopenia, lymphocyte depletion, and cytokine storm. Administered by intravenous infusion, has an immunomodulatory effect by down-regulating the production of proinflammatory cytokines, increasing the production of anti-inflammatory cytokines, and recruiting naturally occurring anti-inflammatory cells into relevant tissues to combat the inflammatory process associated with a variety of diseases. In this outbreak, diseases with potentially fatal inflammation caused by cytokine storms are the leading causes of death in patients with COVID-19.
MSCs have a significant effect on the treatment of patients infected with COVID-19. Studies have shown that plasma cytokine levels in severe COVID-19 patients are significantly increased, suggesting that cytokine storm plays an important role in the lethal process of COVID-19. Therefore, some researchers have proposed a new idea that the use of MSC transplantation technology can rapidly and significantly improve the prognosis of severe and critical patients, effectively avoid the cytokine storm, without obvious side effects. Moreover, the safety and reliability of this method have been tested by clinical practice, which provides new hope for reducing the mortality rate of severe and critical patients with new coronary artery disease.
In addition, viral-induced acute respiratory distress syndrome is also one of the important causes of death. Recent studies have found that MSCs have great potential in the treatment of acute respiratory distress syndrome through immune regulation, proliferation, differentiation and repair, and anti-microbial effects.
Applications of MSCs in inflammation
MSCs have immune regulatory functions and strong paracrine effects in the inflammatory environment, which can be used to treat inflammatory diseases. large number of studies have shown that MSCs can regulate inflammation and promote tissue regeneration in a variety of ways, so as to alleviate or even treat a variety of inflammatory diseases, such as inflammatory bowel disease and arthritis. Recently, scientists have found that an anti-inflammatory factor (CD200) is highly expressed in placental MSCs, inhibiting the production of proinflammatory factors but also increasing the formation of anti-inflammatory response factors and immune regulatory factors, thus playing a role in the treatment of diseases. In addition, studies have shown that placental mesenchymal stem cells are safe and effective in the treatment of knee arthritis.
The anti-aging effect of MSCs
Aging is a major problem facing mankind, and the pursuit of immortality is an eternal topic. After more and more studies, mesenchymal stem cells have been found to play a great role in combating aging. Cell senescence and stem cell depletion, as important markers of aging, are important factors driving the occurrence and development of senile diseases. The study found that many symptoms of senile patients with the debilitating syndrome were improved without adverse reactions after the reinfusion of young MSCs. The safety and efficacy of MSCs have been demonstrated.
Conclusion
MSCs have good application prospects, and they have no or low immunogenicity, no MHC restriction, can induce host immune tolerance, reduce transplant rejection, and can be applied in tissue engineering, tissue and organ transplantation, gene therapy, immunotherapy, and so on in the future. And MSCs presumably also play a great role in COVID-19. It is believed that after further research by scientists. MSCs can play a significant role in the complex diseases facing human beings at present.