a cure for memory loss could be closer than we think

how scientists at uhn are uncovering the immune system’s hidden role in memory loss

by university health network (uhn)

published mar 27, 2026

last updated mar 30, 2026

5 minute read

dr. valeria ramaglia's work explores the role of the immune system in brain health and disease, particularly in multiple sclerosis. uhn

this story was provided by a client for commercial purposes.

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it’s a reality that many families know all too well: watching a loved one slowly disappear before your eyes, day by day until they are almost unrecognizable. living in a body they are no longer in control of, and a brain no longer their own. this is the heartbreaking truth for people living with neurodegenerative diseases such as progressive multiple sclerosis (ms), parkinson’s disease, as well as alzheimer’s and other dementias – a truth that a growing number of canadians will face over the next 10-to-20 years.

by 2030, researchers project that nearly one million people in canada will be living with dementia. by 2050, that number is expected to reach 1.7 million.

despite these staggering projections, there are still many unknowns about neurodegenerative diseases and memory loss, but progress is accelerating in promising ways.

within the walls of the krembil brain institute, that progress is taking shape.

pushing the boundaries of research and going beyond the known

the krembil brain institute at uhn’s toronto western hospital is home to one of the world’s largest and most comprehensive teams of physicians and scientists working together to prevent and confront diseases of the brain and spine. it treats more patients living with neurological conditions than anywhere else in the country.

as canada’s largest research and teaching hospital, the krembil brain institute is known for pushing the boundaries of research and innovation, with a commitment to develop new and more effective treatments. the goal is not only to improve quality of life for people living with these diseases, but eradicate these diseases all together.

a major area of focus for the krembil brain institute is neurodegeneration and memory loss. dr. valeria ramaglia, one of krembil brain institute’s newest scientists and an assistant professor of immunology at the university of toronto, is among the researchers pushing this work to new levels. her work explores the role of the immune system in brain health and disease, particularly in multiple sclerosis.

multiple sclerosis as a window into memory loss

“canada has one of the highest rates of ms in the world,” says dr. ramaglia. “this disease brings on a wide range of symptoms that often worsen with age. the result is what we call progressive ms, and one of its most devastating consequences is memory loss. there is no fix for memory loss in progressive ms. that is what we are looking to solve.”

through studying brains donated to research by people with progressive ms, dr. ramaglia and others in the field made a groundbreaking discovery: clusters of immune cells sitting at the border of the brain.

“these clusters should not be there,” says dr. ramaglia. “we have to ask ourselves: what are these cells and what are they doing?”

by using new tools that let them look closely at how brain cells behave, her team found that these immune cells produce important immune proteins called “complement.”

“in simple terms, complement are a group of proteins, mainly produced by the liver and released in the blood, that help your immune system fight infection,” explains dr. ramaglia. “but in ms, complement is produced at the brain border, and it is linked to damage in memory-critical regions like the hippocampus.”

studies in pre-clinical models in her lab suggest that complement is not only linked to the damage but could be the cause of it.

earlier work from dr. ramaglia on the role of the complement system in nerve trauma led to a patent and the founding of a pharmaceutical company that develops complement inhibitors to treat neuroinflammation and neurodegeneration. now the aim is to test whether drugs that target complement at the brain border can help protect the brain’s memory centres. this approach has also inspired a new line of research in the ramaglia lab that extends beyond progressive ms to other age-related diseases of the brain that steal memory.

if complement contributes to memory loss in progressive ms, could the same mechanism be occurring in other neurodegenerative diseases, such as alzheimer’s?

her motivation is also personal. “i know firsthand what it means to see a loved one fade,” says dr. ramaglia, whose father was diagnosed with alzheimer’s disease while she was still in university. “i share the urgency to find a solution — and i have made it my mission.”

connecting the findings to alzheimer’s

this question aligns with a groundbreaking theory proposed by uhn senior scientist dr. donald weaver, who has suggested that alzheimer’s disease may function as an autoimmune disorder — an idea that challenges decades of conventional thinking.

for decades, scientists have focused on beta‑amyloid as an abnormal protein believed to build up in the brain and damage its cells, contributing to alzheimer’s disease. dr. weaver offers a different view: beta‑amyloid may actually be a normally occurring molecule part of the brain’s immune response, helping to repair tissue and fight infection.

according to this theory, alzheimer’s begins when beta‑amyloid can no longer distinguish between invading bacteria and the brain’s own cells, leading it to mistakenly attack the very brain cells it is supposed to be protecting — an immune system misfire.

if alzheimer’s involves immune‑driven damage, then complement proteins at the brain’s borders may be key players.

dr. ramaglia’s work is helping determine whether the same harmful complement activity seen in progressive ms is also present in alzheimer’s disease, and whether blocking that activity could protect the brain.

a pathway toward new treatments

now that scientists have unraveled this first set of clues in understanding the immune system’s role in memory loss, the next challenge lies in identifying when, where and how these immune pathways are activated. “we need to understand exactly when and where complement becomes harmful and by which mechanism,” says dr. ramaglia. “only then can we design brain-penetrant drugs that reach the right targets at the right time.”

it is also essential to recognize that not all patients develop neurodegenerative diseases in the same way. an additional challenge, therefore, is identifying which individuals are most likely to benefit from immune-targeted therapies. the ramaglia lab is working to discover biomarkers — measurable signals in blood or spinal fluid — that can help match the right treatment to the right patient, paving the way toward more personalized and effective therapies in the future.

the krembil brain institute is uniquely positioned for this work. with access to patient spinal fluid and advanced imaging, the team can study complement activity directly in people living with alzheimer’s and other neurodegenerative diseases, an essential step toward developing clinical trials.

there’s no cure without research

to move this research forward, funding is urgently needed for pre‑clinical studies that test when, where and how complement drives disease. these early studies will build the scientific rationale for complement‑targeting therapies to advance into human trials.

“research is our greatest opportunity to understanding these diseases,” says dr. ramaglia. “at the krembil brain institute, we are widening the breadth of our research and asking new questions. what if diseases of the brain where we initially thought that the immune system was not involved are in fact driven by immune mechanisms? looking at how the immune system interacts with nerve cells is where the new answers may be found.”

and for the first time in a long time, those answers finally feel within reach.

this story was provided by university health network (uhn) for commercial purposes.