Canadian researchers find brain inflammation in long-term COVID patients

Leslie Ann Coles knew “almost immediately” something was wrong after her COVID-19 infection in January 2021. Filmmaker from Woodbridge, Ontario.

Leslie Ann Coles knew “almost immediately” that something was wrong after her COVID-19 infection in January 2021.

The Woodbridge, Ontario-based filmmaker had never had writer’s block in her life, but she couldn’t find the words to make revisions to a script she’d been working on.

“It was really scary,” Coles said.

His emotional state also changed.

“I’ve never suffered from depression in my life,” Coles said. “My friends refer to me as the eternal optimist.”

But her usual passion for life and work had waned, leaving her feeling “listless, for lack of a better word,” she said.

Researchers have been trying to understand what causes the many symptoms of long-term COVID, including the neurological problems suffered by hundreds of thousands of Canadians like Coles.

Now, a team led by the Center for Addiction and Mental Health (CAMH) has found physiological evidence of brain inflammation in people with cognitive and depressive symptoms months after their COVID-19 infections.

Autopsies of people who died amid severe COVID-19 infection previously showed they had brain inflammation, said Dr. Jeffrey Meyer, head of the mood and anxiety neuroimaging program at CAMH and lead author of the published study. Thursday at JAMA Psychiatry. .

The current study shows brain inflammation in people who have recovered from an acute phase of COVID-19 but continue to have long-lasting neurological problems, even though their initial infection was not severe, he said.

“These are people who have had COVID for a long time and haven’t really been hospitalized. They have mild to moderate acute COVID, but then they have considerable symptoms,” Meyer said.

“Our study shows that there is inflammation months to more than a year later in people who have COVID for a long time.”

The researchers performed positron emission tomography (PET) scans on the brains of 20 participants who had started suffering from depression within three months of testing positive for COVID-19.

Most of them had additional cognitive problems associated with prolonged COVID, including problems with memory and concentration, also known as “brain fog.”

The researchers compared those scans to 20 brain scans of “healthy” people that had been done before the pandemic.

They found that people who had COVID for a long time had higher levels of translocator protein, or TPSO, in their brains. TSPO appears in glial cells, which increase with inflammation.

The most pronounced increase in inflammation was in two areas of the brain: the ventral striatum and the dorsal putamen, according to the study.

Those are parts of the brain associated with the ability to experience enjoyment, energy and motivation levels, cognitive processing, and speed of movement.

“We know that when there’s a lesion in these brain regions, you get some of the symptoms that we’re seeing in people with long-term COVID,” Meyer said.

COVID-19 sufferers have been eagerly awaiting these findings “to validate that brain fog is real and caused by functional changes from COVID-19,” said Susie Goulding, founder of online COVID support group Long-Haulers Canada, which helped recruit study participants.

“Hopefully this concrete evidence will provide understanding and guidance” to family doctors who encounter patients describing neurological symptoms after COVID infection, Goulding said in a text message to The Canadian Press.

Dr. Angela Cheung, co-director of a national long-term COVID research network and a senior physician and scientist at the University of Toronto Health Network, said the study confirms what long-term COVID researchers suspected for some time.

“We have always thought that inflammation plays a role,” said Cheung, who was not involved in the CAMH study.

“It’s been difficult to measure inflammation in patients.” she said. “This study shows that in people with persistent cognitive and depressive problems, there is neural inflammation in the brain.”

But Dr. Lakshmi Yatham, a psychiatrist at the University of British Columbia who researches mental health issues related to COVID-19, said while the study is valuable, there are important limitations to consider.

“It’s a good first attempt at looking at inflammation. But at this stage, inflammation cannot be attributed to depressive symptoms,” Yatham said.

One limitation, he said, is that some of the participants had previous experiences with depression.

However, Meyer said those people made up less than half of the participants, and any previous depressive symptoms had resolved before contracting COVID-19.

Yatham said more studies with a control group of people who have recovered from COVID-19 and have not had COVID for a long time are needed to compare levels of brain inflammation. That was not possible in the CAMH study because the control group’s brain scans had been done before the pandemic.

One of the next steps for the CAMH team is to “test whether some types of anti-inflammatory or inflammation-altering drugs might be useful for long-term COVID,” Meyer said.

Cheung said that other researchers are also planning studies of anti-inflammatory drugs.

Leslie Ann Coles has learned tactics to fix memory problems that persist to this day, including constantly writing things down and taking photos on her phone.

For her, as for many other long-term COVID sufferers, the next steps in the research cannot come soon enough.

“I hope they find ways that this study can help people with long-term COVID to recover,” he said.

This report by The Canadian Press was first published on June 1, 2023.

Canadian Press health coverage is supported through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

Nicole Ireland, The Canadian Press