Stem Cells Used in COVID-19

  • As of June, there were more than 7 million cases of COVID-19 worldwide. Compared with the rising number of infections, what is even more disturbing is that many countries are overwhelmed by medical resources, and there is a lack of special drugs to rescue critical patients.

    The function of the stem cell is to control and maintain cell regeneration. Generally speaking, there is a population of intermediate progenitor cells called "directional progenitor cells" between stem cells and their terminally differentiated progeny cells, which have limited expansion capacity and limited differentiation potential. The function of these cell populations is to increase the number of differentiated cells produced by stem cells after each division. Stem cells have the ability to renew themselves, but the division of stem cells is actually relatively asymmetric.

    In adult organs, stem cells can continue to divide to repair tissues, or they are at rest as in mammalian brain tissue. Stem cells can divide symmetrically during their development to expand their numbers, or they can renew themselves and produce more differentiated progenitor cells through asymmetric division.

    In simple terms, a stem cell is a type of cell with infinite or immortal self-renewal capacity, capable of producing at least one type of highly differentiated progeny cells.

    So, since stem cells are so magical, can it help the treatment of COVID-19?

    Stem cells are primitive cells with the potential for self-replication and multi-directional differentiation. Under certain conditions, it can differentiate into a variety of functional cells or organs, called "universal cells" in the medical world. Stem cells exist in various tissues of the body, including bone marrow, fat, dental pulp, placenta, and umbilical cord. Stem cells can be divided into embryonic stem cells and adult stem cells. Adult stem cells have limitations with their potency; unlike embryonic stem cells (ESCs), they are not able to differentiate into cells from all three germ layers. As such, they are deemed multipotent. However, reprogramming allows for the creation of pluripotent cells, induced pluripotent stem cells (iPSCs), from adult cells. These are not adult stem cells, but somatic cells (e.g. epithelial cells) reprogrammed to give rise to cells with pluripotent capabilities.

    The mesenchymal stem cells are a type of adult stem cells. It can "become" a variety of cells in the body, such as osteoblasts and muscles cells, liver cells, etc. In addition, mesenchymal stem cells have the characteristics of immunomodulation and low immunogenicity, and the requirements for matching are not strict. These characteristics have given mesenchymal stem cells broad prospects for disease treatment.

    "Inflammatory factor storm is an important cause of clinical severe illness and even death in many patients." Relevant expert doctors said. Once the inflammatory factor storm is formed, it will cause the body's immune system to overreact, while the immune system kills the virus, it also kills a large number of normal cells in the lungs, severely destroy the ventilation function of the lungs, and lead to respiratory failure until the death of hypoxia.

    How to quiet the out-of-control immune system has become the direction of scientific researchers. Mesenchymal stem cells with immunomodulatory and anti-inflammatory capabilities have entered the vision of various scientific research institutions.

    Existing research has confirmed that on the one hand, mesenchymal stem cells can effectively control the excessive immune response and suppress the damage caused to multiple organs of the human body by virtue of low immunogenicity and the regulation of innate and acquired immunity. In terms of stem cells, after entering the body through intravenous infusion, some of them accumulate in the lungs, which has the potential to improve the microenvironment of lung cells, protect alveolar epithelial cells, and improve lung function.

    "Previous clinical studies have shown that mesenchymal stem cell infusion for the treatment of acute lung injury, severe pneumonia, acute respiratory distress syndrome, respiratory failure and other respiratory diseases have shown good safety and effectiveness, and can improve patient oxygenation Index, reduce the inflammatory damage to the lungs." Relevant expert doctor said.

    Although not directly eliminating the virus, the stem cells may help alleviate the inflammatory response, improve lung function, and improve the survival rate of critically ill patients. A number of clinical trials have confirmed that mesenchymal stem cells are effective in the treatment of new patients with severe coronary pneumonia. In the context of lack of special treatment programs, mesenchymal stem cells have become a hope for some patients with severe new pneumonia.