The Covid-19 pandemic sparked considerable research worldwide into innovative treatments that could combat some of the symptoms of this disease. The amazing versatility of mesenchymal stem cells (MSCs) has been harnessed in more than 80 clinical trials in the treatment of Covid-19 patients (1).
The science and research have progressed rapidly since the pandemic arose and stem cell therapies have been shown to be both safe and effective at reducing severe acute respiratory distress syndrome (SARDS) in severely ill Covid-19 patients (2). These clinical trials, exploit the anti-inflammatory and immunomodulatory potential of MSCs to help control lung damage caused by the so called “cytokine storm” seen in some patients.
The cytokine storm is an overreaction of the body’s immune system where it produces an overload of proteins called cytokines in response to the virus. This can cause devastating damage to the lungs and other organs.
The treatment is simple in principle, using 1-3 doses of MSCs in Covid patients. The MSCs travel through the bloodstream to the sites of damage and, thanks to their unique ability to produce certain key proteins, they help the body to repair the injured respiratory tissues.
The technology typically involves the extraction and expansion of MSCs in cell culture and as these cells can grow and increase in number rapidly. Bone marrow and adipose tissue have been used as sources of MSCs, but umbilical cord tissue is frequently used, and a single umbilical cord has the capability to yield plenty of these cells to treat many patients.
Several double-blind studies in which the doctors and patients do not know who received the actual cell infusion or a placebo control have shown that infusions of MSCs from umbilical cord tissue used patients with Covid-19 with SARDS are safe. The cell-based treatments were also shown to be effective at reducing mortality and recovery time in seriously ill patients (3).
The science has continued to evolve and unravel possibilities to help patients with post Covid related complications. There is growing interest in the potential use of MSCs in those suffering from the debilitating effects post Covid lung fibrosis which results in scarring of lung tissue and inhibits normal breathing function. This can lead to patients who are badly affected becoming dependent on oxygen. As MSCs can promote healing in damaged tissues and organs it is hoped that their regenerative properties may help those experiencing ongoing respiratory problems. Preclinical and clinical trials with autologous (self to self) or allogeneic (donor to recipient) MSCs sourced from bone marrow, adipose tissue or umbilical cord tissue demonstrate that the stem cells can relieve non covid related fibrotic lung disease by reducing inflammation, regenerating and remodeling damaged tissues, and reducing lung cell death (4). The first reported case of this beneficial effect being exploited in a patient with post Covid lung fibrosis involved critically ill 30 year old male who was dependent on mechanical ventilation for his condition. The patient made a dramatic recovery and was able to be discharged from intensive care after 30 days of umbilical cord tissue derived MSC therapy (5).
Looking at the wider spectrum of symptoms experienced by sufferers of long Covid, including but not limited to fatigue, muscle pain and weakness and brain fog, researchers have suggested that the immune system continues overreacting even though the virus has been effectively eliminated. Antibodies and cytokines may continue to damage cells and tissues throughout the body and patients may be experiencing the effects of continued widespread inflammation. Given the immunomodulatory and anti-inflammatory properties of MSCs, they may prove to be effective in reducing these debilitating symptoms which can affect day to day activities.
A clinical trial has been launched by Hope Biosciences in Texas to determine the safety and efficacy of autologous adipose tissue derived MSC therapy for patients with post Covid syndrome. This FDA authorised study is enrolling participants who have had a PCR positive Covid test result in the previous 24 months and who are experiencing any of the typical complications of long Covid. The patients receive four infusions of approximately 200 million MSCs per dose (6, 7) and it is hoped that the remarkable potential of these stem cells will help to relieve the often debilitating symptoms of the condition.
Cutting edge stem cell therapies are increasingly becoming a game changer in modern medicine, providing hope for the treatment of many diseases in the present and the future and Covid is no exception. In summary, the results of recent and ongoing trials support the relevance of MSC-based therapies in the acute stages of Covid-19, as has been extensively reported. Furthermore, a role is emerging for MSCs in the treatment of critical post Covid fibrotic complications and additionally, in long Covid which afflicts up to 2% of people in the UK according to the ONS (8).
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