Thursday December 13, 2018

Study: Dementia Risk to 50-year-olds With Raised Blood Pressure

How middle-age hypertension raises dementia risk later

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A high blood pressure level but still below the usual threshold for treating hypertension can put 50-year-olds at increased risk of developing dementia later, revealed a study led by an Indian-origin researcher.

According to the American Heart Association, normal blood pressure is below 120/80 mmHg.

People with a systolic blood pressure (the top number) of 130 mmHg or more at the age of 50 had a 45 per cent greater risk of developing dementia than those with a lower level at the same age.

The risk was 47 per cent even in people with no heart or blood vessel-related conditions.

“Our work confirms the detrimental effects of midlife hypertension for risk of dementia,” said lead author Archana Singh-Manoux, Professor at the French National Institute of Health and Medical Research (INSERM) in Paris.

Representational image.
Representational image. Pixabay

The reason for the increased risk of dementia includes the fact that high blood pressure is linked to silent or mini strokes (where symptoms often are not noticeable), damage to the white matter in the brain, which contains many of the brain’s nerve fibres, and restricted blood supply to the brain.

This damage may underlie the resulting decline in the brain’s processes, the researchers explained in the study of nearly 9,000 people, published in the European Heart Journal.

However, the association was not seen at the ages of 60 and 70, and diastolic blood pressure (the bottom number) was not linked to dementia.

Also Read: Rutgers Researchers Develop Automated Robotic Device For Faster Blood Testing

“Our analysis suggests that the importance of mid-life hypertension on brain health is due to the duration of exposure,” the researcher said.

“So we see an increased risk for people with raised blood pressure at age 50, but not 60 or 70, because those with hypertension at age 50 are likely to be ‘exposed’ to this risk for longer,” she added.

Another study reported in the journal Cardiovascular Research showed that higher risk of developing dementia in hypertensive patients occurs due to significant alterations in three specific white matter fibre-tracts linked to executive functions, processing speed, memory and related learning tasks — brain areas associated with dementia. (IANS)

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Scientists Discover A New Method To Fight Alzheimer’s, Dementia

Worldwide, about seven percent of people over 65 suffer from Alzheimer's or some form of dementia, a percentage that rises to 40 percent above the age of 85.

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alzheimer's, cholesterol
One hemisphere of a healthy brain (L) is pictured next to one hemisphere of a brain of a person suffering from Alzheimer disease. VOA
Eliminating dead-but-toxic cells occurring naturally in the brains of mice designed to mimic Alzheimer’s slowed neuron damage and memory loss associated with the disease, according to a study published Wednesday that could open a new front in the fight against dementia.The accumulation in the body of “zombie cells” that can no longer divide but still cause harm to other healthy cells, a process called senescence, is common to all mammals.

Scientists have long known that these dead-beat cells gather in regions of the brain linked to old age diseases ranging from osteoarthritis and atherosclerosis to Parkinson’s and dementia.

Prior research had also shown that the elimination of senescent cells in ageing mice extended their healthy lifespan.

But the new results, published in Nature, are the first to demonstrate a cause-and-effect link with a specific disease, Alzheimer’s, the scientists said.

Alzheimer's
A lady suffering from Alzheimer’s. Flickr

But any treatments that might emerge from the research are many years down the road, they cautioned.

In experiments, a team led by Tyler Bussian of the Mayo Clinic in Rochester, Minnesota used mice genetically modified to produce the destructive, cobweb-like tangles of tau protein that form in the neurons of Alzheimer’s patients.

The mice were also programmed to allow for the elimination of “zombie” cells in the same region.

“When senescent cells were removed, we found that the diseased animals retained the ability to form memories, and eliminated signs of inflammation,” said senior author Darren Baker, also from the Mayo Clinic.

The mice likewise failed to develop Alzheimer’s signature protein “tangles”, and retained normal brain mass.

 

Alzheimer's
Alzheimer’s disease patient Isidora Tomaz, 82, sits in an armchair in her house in Lisbon, Portugal. It’s predicted that by 2050, 135 million Americans are going to suffer from mild cognitive impairment, a precursor of Alzheimer’s. VOA

Keeping zombies at bay

A closer look revealed that the “zombies” belonged to a class of cells in the brain and spinal cord, called glia, that provide crucial support and insulation to neurons.

“Preventing the build-up of senescent glia can block the cognitive decline and neuro-degeneration normally experienced by these mice,” Jay Penney and Li-Huei Tsai, both from MIT, wrote in a comment, also in Nature.

Bussian and his team duplicated the results with pharmaceuticals, suggesting that drugs could one day slow or block the emergence of Alzheimer’s by keeping these zombie cells at bay.

“There hasn’t been a new dementia drug in 15 years, so it’s exciting to see the results of this promising study in mice,” said James Pickett, head of research at Alzheimer’s Society in London.

 

Alzheimer's
The accumulation in the body of “zombie cells” that can no longer divide but still cause harm to other healthy cells, a process called senescence, is common to all mammals. IANS

For Lawrence Rajendran, deputy director of the Dementia Research Institute at King’s College London, the findings “open up new vistas for both diagnosis and therapy for neurodegenerative diseases, including Alzheimer’s.”

Up to now, dementia research has been mostly focused on the diseased neurons rather than their neighboring cells.

“It is increasingly becoming clear that other brains cells play a defining role,” Rajendran added.

Several barriers remain before the breakthrough can be translated into a “safe, effective treatment in people,” Pickett and other said.

The elderly often have lots of harmless brain cells that look like the dangerous senescent cells a drug would target, so the molecule would have to be good at telling the two apart.

Also Read: Common Painkillers Triple Harmful Side Effects in Dementia

Worldwide, about seven percent of people over 65 suffer from Alzheimer’s or some form of dementia, a percentage that rises to 40 percent above the age of 85.

The number afflicted is expected to triple by 2050 to 152 million, according to the World Health Organization, posing a huge challenge to healthcare systems. (VOA)