This article was originally published on Today’s Medical News
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Dutch researchers have discovered a subgroup of people in the national brain bank whose brains show signs of Alzheimer’s disease but who never showed any symptoms during their lifetime.
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Some experts say this is a rare event, but it is possible because it can take decades from the initial amyloid deposits in the brain that characterize the disease to the onset of symptoms.
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So-called resilience to Alzheimer’s symptoms can develop through genetics and lifestyle choices, but some research suggests that cognitively enhancing activities may help ease those symptoms.
Dutch researchers recently made a surprising discovery after examining data from more than 2,000 brains in the Dutch Brain Bank.
Their research is Acta Neuropathological Communications — There are obvious signs in certain groups of people, Alzheimer’s disease Although their brain tissue was abnormal, they did not develop symptoms during their lives.
Admittedly, they only identified 12 of these individuals from available brain tissue with the necessary clinical information recorded, but this raised many questions about the disease itself and what makes people resilient to it.
Dementia is 55 million Worldwide, up to 70% of people suffer from Alzheimer’s disease, which is characterized by brain cell loss associated with the toxic buildup of two proteins. Amyloid and Tau.
The most common symptoms of Alzheimer’s disease are memory loss; cognitive impairment; problems with speech, cognition, spatial orientation, reading, or writing; and significant changes in personality and behavior.
Because Alzheimer’s disease is progressive, these symptoms are usually mild at first but tend to become more severe over time.
What causes Alzheimer’s disease to progress without symptoms?
The phenomenon of the absence of Alzheimer’s symptoms is called “resilience.”
In the resilient group, the researchers found that a type of brain cell called astrocytes press release These cells, known as the brain’s protective “garbage collectors,” appear to produce more of an antioxidant called metallothionein.
Astrocytes can interact with microglia in the brain to increase inflammation, but these pathways associated with Alzheimer’s disease appeared to be less active in the resilient group.
The researchers also found that the response of brain cells that are supposed to clear toxic misfolded proteins was relatively normal in the resilient group.
This so-called “unfolded protein response” commonly affects people with Alzheimer’s, and there are signs that the brain cells of resilient people had more mitochondria than those of other Alzheimer’s patients, meaning energy production was stronger in the resilient group.
Cognitive reserve and the phenomenon of “resilience”
Genetics and lifestyle may influence this species’ resilience. David Merrill, MD“It’s important to understand that the effects of depression are not just limited to the brain,” said Dr. Schneider, a geriatric psychiatrist and director of the Pacific Brain Health Center at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California, who was not involved in the study. Today’s medical news.
“Cognitive reserve“Rehabilitation, the brain’s resilience to injury, plays an important role. In addition, genetic factors, lifestyle and environmental influences may modulate the onset and severity of symptoms regardless of the underlying pathology,” says Merrill.
“The authors are talking about changes in the function of neural support cells, such as astrocytes and microglia, or components of neural cells, such as energy-producing mitochondria,” he added.
Dr. Yuko Hara“We’re seeing a lot of research being done to find the right treatment for Alzheimer’s disease,” said director of aging and Alzheimer’s prevention at the Alzheimer’s Drug Discovery Foundation, who was not involved in the study. MNT There can be a lag of 20 to 30 years between the first signs of amyloid deposits in the brain and the onset of symptoms.
Hara explained that there are ways that we can increase our cognitive reserve over time.
“Cognitive reserve refers to the brain’s ability to resist age-related changes and the effects of disease-related pathologies, such as beta-amyloid, that typically lead to cognitive decline. Based on this phenomenon, the knowledge and experiences gained throughout one’s life can help one better cope with pathologies such as beta-amyloid and preserve cognitive function for longer. There are many things one can do to increase cognitive reserve: take classes to learn new things, read books, learn a new language, learn how to play an instrument, or stimulate and challenge one’s brain in other ways.”
How common is asymptomatic Alzheimer’s?
Merrill said adult children or spouses of Alzheimer’s patients sometimes come in for testing even if they don’t have symptoms, but generally most patients seek treatment when they develop symptoms.
He explained: “It is not uncommon for patients to have no symptoms, whether they have Alzheimer’s or not. [Alzheimer’s] Being able to mimic normal aging will lead many to answer the question: Is what is happening normal or is it the beginning of aging? [Alzheimer’s disease]? “
“We’re not looking at this as a categorical phenomenon of whether symptoms are present or absent, but rather as a continuum of symptoms, so it’s not surprising that so few brain donors in this study had any symptoms,” Merrill added.
“Although Alzheimer’s disease pathology can be seen in asymptomatic individuals, it remains the exception and not the rule in clinical practice. This is consistent with emerging research suggesting that Alzheimer’s disease can exist without overt cognitive symptoms due to cognitive reserve and compensatory mechanisms in the brain, as reported in this study.”
– David Merrill, MD
Hara said signs of Alzheimer’s can begin quite early in life, even before typical symptoms appear, and cited some fascinating research on the phenomenon.
“There are many people who have pathological markers of Alzheimer’s disease but don’t have symptoms of Alzheimer’s disease. Beta amyloid, which is a pathological marker of Alzheimer’s disease, can start to build up in the brain. From your 20s” she pointed out.
“Amyloid deposition in the brain begins decades before symptoms of Alzheimer’s appear. One study showed that 44% of 90-year-olds with good cognitive function There was amyloid lesion” said Hara.
“In some cases, gene mutations confer a protective effect against genetic forms of Alzheimer’s disease,” she added.
But these appear to be rare occurrences, she noted.
“A 2019 Survey A woman with a presenilin 1 (PSEN1) mutation, a genetic cause of early-onset Alzheimer’s disease, has been reported. She did not develop dementia in her 40s like other people with the mutation. Instead, she suffered only mild memory loss in her 70s. The researchers concluded that the woman ” Apoe 3 The Christchurch mutation may have conferred resistance to the development of Alzheimer’s disease symptoms for up to 30 years, despite having very high levels of beta-amyloid in the brain.”
Strategies to Prevent Alzheimer’s Disease
Although there are genetic factors that determine a person’s risk of developing Alzheimer’s, a 2020 report found that: Lancet It was suggested that alcohol consumption, smoking, unhealthy diet, lack of education, lack of social interaction and lack of physical activity may all contribute to the progression of the disease.
In addition, according to the study, Lifestyle interventions Anything that stimulates brain activity can help increase cognitive reserve and prevent some of the symptoms.
for example, Neurology A study published in 2021 found that high-level cognitive activities like reading, playing games like checkers or puzzles, and writing letters could delay the onset of Alzheimer’s disease by five years in people over the age of 80.
Another study published in 2022 found that PNASThey found that spending more time engaged in cognitively passive activities, such as watching television, increased the risk of dementia, whereas spending more time engaged in cognitively active tasks, such as using a computer, decreased the risk of dementia.
And according to one study JAMA Network OpenA study published in July 2023 found that frequent brain-stimulating activities such as journaling, playing chess, and solving crossword puzzles may lower the risk of developing dementia in older adults.
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