UCD, UT get $53.6M to seek answers for Black, Mexican American patients with dementia
UC Davis researcher Charles DeCarli has been pursuing the causes of dementia in African Americans and Mexican Americans for decades, and now he’s won $53.6 million from the National Institutes of Health to hone in on the answers.
He and a geneticist at the UT Health Science Center at Houston, Dr. Myriam Fornage will be investigating the role that a common type of brain lesion, known as incidental white matter lesions, play in cases of dementia that are more prevalent in both Black and Mexican Americans.
“A good friend of mine, (Dr.) Vladimir Hachinski, noticed that there were these abnormal signals in the white matter of brains of people who were older,” said DeCarli, a professor of neurology. “This was back in 1987, and for the longest time we’ve been trying to figure out what they all mean. What we know about them is they seem to be related to risk factors for vascular disease: heart attacks, stroke,...hypertension, high cholesterol, diabetes, obesity.”
Indeed, DeCarli’s own lab is one of the research groups that has established the link between these diseases and many dementia cases in Hispanics and Blacks, prompting them to put out the word that changes in diet and exercise could help stem the progression of the disease.
“We can treat it,” DeCarli said. “There’s already good evidence (of) that.”
If physicians and patients work together to careful control blood pressure and diabetes, he said, they can reduce the likelihood of those white matter lesions and the likelihood that patients will develop a dementia.”
By studying brains donated by 423 individuals who had dementia, DeCarli and his team discovered that cerebrovascular disease was much more likely to be a cause of dementia than Alzheimer’s disease in Hispanics and in African Americans than in non-Hispanic whites.
Their findings, published in March 2019 in the Journal of Alzheimer’s Disease, noted that 21 percent of Hispanics had cerebrovascular damage and 54 percent had a combination of both Alzheimer’s disease and cerebrovascular degeneration.
African-American subjects had a less-marked but still noteworthy results, with 11 percent of those brains showing signs of only cerebrovascular damage and 37 percent showing both Alzheimer’s disease and cerebrovascular disease. The brains from non-Hispanic whites had that same incidence of both diseases, but only 4 percent of them bore any sign of cerebrovascular disease.
“Almost all of us, after the age of 60, have a few of these little speckles in our brains,” said DeCarli, director of the UC Davis Alzheimer’s Disease Research Center. “The question becomes then: What do they mean? They do in some ... studies show that they are associated with poorer thinking ability, but there’s never been a study until now in which someone would come in with a complaint with their memory, we’d do an MRI scan, find out if they have these white-matter lesions and, if they do, then we follow them and study them very carefully to see what the impact on their thinking will be.”
That’s exactly what DeCarli and Fornage will be doing in this new study, and they will be seeking a little more than 2,200 study participants in several cities across the nation starting in September 2021. They are looking for people of Mexican, Black and Caucasian origins.
“We’re going to look at: What is their risk for having them? And, how do they affect their thinking ability?’ DeCarli said. “But also, (we will) do some very sophisticated scientific investigation about what is the biology of these abnormal lesions: Why are they forming? Why are they getting worse over time? Why are they affecting people?”
The six-year grant that is funding this work has the distinction of being the largest such award that the UC Davis School of Medicine has received from the NIH, a unit of the U.S. Department of Health & Human Services and the largest biomedical research agency in the world.
“The magnitude of this NIH grant underscores UC Davis Alzheimer’s Disease Research Center’s national prominence and research leadership,” said Allison Brashear, a neurologist and dean of the UC Davis School of Medicine. “This multi-year research award will enable us to make game-changing advancements in our understanding and treatment of dementia.”
DeCarli said he and Fornage already had been working together on these abnormal white matter lesions for more than 10 years because the lesions are “very, very genetically determined.”
“It may turn out that, in fact, what we really are going to understand is that dementia has many causes at later life and for some people, it’s these white-matter lesions. Some people, it’s Alzheimer’s disease, Some people, it’s a combination of both,” DeCarli said. “This will allow us to create what we call a risk score and give physicians a better idea of how to diagnose what’s causing the thinking abnormalities and possibly better ways to treat it.”
These lesions are incredibly common, though, DeCarli said, so there’s no need to get anxious or overwhelmed if they appear on a brain scan. In all likelihood, he said, they’re benign and reveal no increased risk of dementia.
This story was originally published October 15, 2020 at 4:20 PM.
