Scientific discovery: Hope for patients with disease that's more common in Quebec

A breakthrough by Quebec researchers offers some initial hope to patients suffering from a disease that is rare worldwide, but more common in the Saguenay-Lac-Saint-Jean region.

Myotonic dystrophy type 1 (DM1) affects about one in 8,000 people worldwide, but about one in 500 in Saguenay-Lac-Saint-Jean due to the founder effect.

DM1 affects patients' muscles in particular, making it difficult for them to move or relax their muscles, for example, after shaking hands. The disease can also affect sleep, digestion, vision, heart rate, the reproductive system and dexterity.

Researchers and physiotherapists Nicolas Dumont of Sainte-Justine Hospital and Elise Duchesne from the Saguenay-Lac-Saint-Jean CIUSSS have succeeded in identifying a molecular signature linked to the muscular deficiencies of this disease.

"We were interested in how the stem cells in these muscles are affected," explained Dumont.

Muscle samples provided by patients enabled researchers to discover that "in these patients, there was a signature of senescence, i.e. cells that stop proliferating, no longer function and accumulate in the body," said Dumont.

While this is a natural process that protects the body from problems such as cancer, the presence of these cells in exaggerated quantities can be a source of inflammation.

"It's a bit like premature aging in patients, and it contributes to the progression of the disease," says Dumont.

The greater this inflammatory profile due to senescent cells, the weaker the patients and the greater the progression of the disease, he added.

The researchers therefore set about testing existing drugs used to treat other diseases in the laboratory to eliminate senescent cells. They succeeded in identifying a molecule that enables the "good cells" in the muscles to start functioning normally again by eliminating the "bad cells."

Although these results are promising, the first clinical trials will not take place for at least another five years, warned Dumont.

In the meantime, patients suffering from this hereditary disease can feel encouraged that science is slowly moving towards a solution to their problem, as doctors currently have nothing to offer them.

"Any new option is a step forward for them," says Dumont. "We're realistic; it's not a miracle drug, but it's still something promising."

The findings were published in the scientific journal Nature Communications.

This report by The Canadian Press was first published in French on July 19, 2023.