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More than a year into the COVID-19 pandemic, medical science is still struggling to cope with the worst manifestation of the disease.

When out-of-control immune systems attack patients lungs and sap their ability to breathe, health care has no sure-fire response. Even with some improvement in treatment, as many as 40 per cent of COVID patients in the intensive-care unit never make it out.

But researchers in Canada and elsewhere believe theres potential lurking inside an unlikely source: a byproduct of child birth.

Discarded umbilical cords are a particularly rich font of mesenchymal stromal cells (MSCs), a type of stem cell that scientists hope could reset that berserk immune system and tamp down damaging inflammation.

At least two clinical trials are in the works in Canada and dozens more in other countries to test the idea on the sickest of COVID patients.

Results of randomized, controlled tests of the cells efficacy are still to come, but early signs are promising. A small handful of case series observational studies that lack a placebo group for comparison have had good results, including one just published by an Iranian team.

At McGill University, a team led by Dr. Ins Colmegna plans to test another MSC product derived from umbilical cord blood, produced by a Swedish company.

The idea here is that youre using a cell that is capable of reversing the damage caused by a huge activation of the immune system, she said. In a way, you are bringing some order and direction to the immune system.

Some experts actually describe COVID-19 as like two different diseases. The first sees the virus itself triggering various symptoms, which clear up in most patients. The second occurs when the immune system goes hyperactive, triggering massive inflammation and assailing the cells of the lung, strangling their ability to shift oxygen to the bloodstream.

In a way, you are bringing some order and direction to the immune system

The result can be acute respiratory distress syndrome (ARDS), the most dangerous symptom of COVID-19, when many patients end up on ventilators fighting for their lives.

Various potential treatments for the condition have been tried, none proving to be a home run.

With their ability to transform into other types of cells, MSCs were originally investigated as a way to regenerate damaged or diseased tissue. The results werent encouraging, but the cells did seem proficient at modulating the immune system, re-adjusting it so it fights off disease but doesnt turn on the body itself, said Stewart.

Unlike single-molecule treatments, they also have a unique ability to multi-task, to target a number of factors causing damage, said Colmegna.

You really are trying to tackle more than one thing at once.

You really are trying to tackle more than one thing at once

How the cells accomplish all that is not entirely clear, but they are associated with small blood vessels that play a key role in healing after injury, said Stewart.

Before the pandemic, the Ottawa team had completed a phase one trial using MSCs to treat ARDS caused by septic shock. A Chinese group reported in October on a study of 61 patients suffering from ARDS due to H7N9 flu. Significantly fewer of the 17 that received the stem cells 17.6 per cent died than those who did not get the treatment (55 per cent).

The cells can be found throughout the body but efforts to harvest them have largely focused on bone marrow and umbilical cords. The latter are the richest source and give up younger cells, Stewart said.

He believes his teams MSC product has an advantage over others as it is derived fresh from living cultures, and is likely more potent than others that are frozen and then thawed.

But the frozen cells are off-the-shelf products that provide more flexibility in emergency cases when speed is of the essence, said Colmegna.

More:

Stem cells from umbilical cords might be the answer for severely ill COVID patients: Canadian researchers - National Post

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