The treatment involves procuring stem cells from a host of possible sources (the patient’s own body or from a donor) and introducing them in the diseased person for the regeneration and repair of damaged tissues. It has been found to be helpful in certain degenerative, autoimmune and skin disorders, and its application for many other conditions is being explored.
But how does it factor into COVID-19 research, what is the evidence for its efficacy and how are doctors approaching the development? FIT explains.
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Recent Research on Stem Cell for COVID-19
A team of doctors and researchers at the Abu Dhabi Stem Cell Center (ADSCC) administered the treatment in the UAE to 73 COVID-19 patients, who were all ‘successfully treated and cured’, without any ‘immediate side effects’, according to a statement by the United Arab Emirates (UAE) health ministry from 1 May.
The process involved a ‘minimally invasive method’ where the patient’s stem cells are extracted, activated and turned into fine mist to be inhaled into the lungs. This was done in addition to the conventional treatment and is expected to work by ‘supporting’ the established protocol of management of symptoms.
The ministry said in the statement, “It is hypothesised to have its therapeutic effect by regenerating lung cells and modulating the immune response to keep it from overreacting to the COVID-19 infection and causing further damage to healthy cells.”
The treatment has successfully undergone the initial phase of clinical trials, demonstrating its safety, and further trials for its efficiency are ongoing; expected to be completed in a couple of weeks.
Dr Fatima al-Kaabi, head of haematology and oncology at the Sheikh Khalifa Medical City in the UAE, told CNBC, “It’s very early to say at this stage.” If all went well, this could reach the market in three months, she added.
Going further back, a pilot study in China on seven COVID-19 patients found that intravenous infusions of donor mesenchymal stem cells (MSC) - multipotent stem cells - improved patient outcomes and helped all of them recover.
Additionally, the US Food and Drug Administration (FDA) approved MSC use in extremely sick COVID-19 patients under expanded access compassionate use on 5 April according to a report in The Scientist, even though the experts seemed divided on the logic on which the investigative treatment may have worked.
A hospital in New York tried the therapy as an experiment on 12 patients, 12 of whom were able to come off ventilators, reports CBS news. Australian based regenerative medicine company Mesoblast has also announced a 300-person trial for its stem cell therapy remestemcel-L to determine whether it will work on patients suffering with severe lung inflammation.
Currently, there are over 20 active stem cell trials for COVID-19, most focusing on the use of MSCs.
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Does the Therapy Hold Promise? Doctors Divided
In conversation with FIT, Dr Pradeep Mahajan, Surgeon and Regenerative Medicine Researcher, elaborated on the reason why the treatment is expected to work well in COVID-19 patients. “Among the sickest of patients, the novel coronavirus, like many other from its family of viruses, has the capability of overtaking the immune system and causing an overreaction in the body in the form of a cytokine storm, wherein the body’s own organs and tissues are attacked. This inflammatory response, in severe cases, leads to Acute Respiratory distress Syndrome (ARDS), the major cause of death in COVID-19 patients.
“Killing the virus is not the solution, it will mutate and keep causing problems. What we can do, instead, is target the body’s reaction to the virus and thereby, reduce inflammation. The immune system will deactivate the virus itself, but the complication arises from hyper inflammation. This is where stem cells come into the picture. Through their immunomodulatory role, they can help induce immuno-suppression by reducing antibody production in the body and preventing a cytokine storm.”
Dr Pradeep Mahajan, Surgeon and Regenerative Medicine Researcher
He adds that knowing the pathology of the disease, the treatment is expected to work well without any risks. “We know the basic pathology, and we are targeting that. Knowing the immunological response of the body, this seems to be one of our best options.”
However, not everybody is this optimistic about the therapy. Doctors and researchers who have been part of the numerous trials across the world have been cautious in making any statements before the availability of some concrete evidence. For instance, Dr Karen Osman, who led the team of New York doctors, told CBS News, “We don't know if the 10 people removed from ventilators would not have gotten better had they not gotten the stem cells. And we would never dare to claim that it was related to the cells." Only a randomized controlled trial would enable a true comparison, she said.
Dr Sumit Ray, critical care specialist in Delhi-NCR, said that the probability of the treatment working is relatively unlikely. Speaking to FIT, he said, “Stem cells have been tried for diabetes and some autoimmune diseases, but the way the immune system responds to those is very different from what happens during COVID-19. A cytokine storm, which is a result of many infections like sepsis, is a necessary evil because this surge is what throws the virus out. Previous studies that had looked into suppressing the storm (mostly against bacteria) were found to be counter-productive, because this inhibits the clearing of the infection from the body, leading to either a continued illness or a resurgence of a secondary infection.”
“According to me, the role of stem cells in this severe infection is very questionable, because the principle in autoimmune diseases and infective pathology is very different. Suppressing the immune system can most definitely lead to other problems and may not help improve outcomes.”
Dr Sumit Ray
Similarly, stem cell biologist Paul Knoepfler of the University of California, Davis, told The Scientist, that he isn’t convinced at all. The disease is so variable and the study numbers so small that, “they don’t have the power from a few patients to say anything about efficacy.” Because MSCs are thought to suppress immunity, “there are also risks that MSCs could weaken the overall immune response to the novel coronavirus,” he adds.
Experts, therefore, seem to be sceptical of the potential of the treatment for COVID-19 and advise waiting for more clinical evidence before reaching any conclusions.