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Eye changes may provide clues to the development of Alzheimer’s. Kobus Louw/Getty Images
  • Although the number of people affected by Alzheimer’s disease is increasing, the mechanisms by which it affects the brain are still controversial.
  • This means that developing early diagnostic tests is challenging, which affects clinical trials to test potential treatments.
  • A recent study suggests that changes in the retina may shed some light on the progression of Alzheimer’s disease.

One of the challenges of treating Alzheimer’s disease is that symptoms appear after damage to the brain.

Many treatments are being developed to target the protein beta-amyloid, as Alzheimer’s disease affects the ability of neurons to signal by accumulating plaques of this protein in the brain. This causes cognitive decline.

Finding ways to detect Alzheimer’s as it progresses may allow affected individuals to receive appropriate treatment earlier and limit the effects of cognitive decline.

Now, a study published in the journal Alzheimer’s and dementiaIt showed that changes in the retina of people with Alzheimer’s disease mimic many of those in the brain.

The researchers looked at retinas from 24 deceased human donors with Alzheimer’s disease, 10 with mild cognitive impairment, and 27 with normal cognitive ability.

The retina is the part of the eye that converts light into nerve signals that allow us to see. During fetal development, it develops as an extension of the brain, and as a result, it gives us a unique understanding of the state of the brain.

The retina also has its own blood barrier, which is made up of tightly packed cells that prevent harmful substances from entering the retinal tissue.

The researchers’ main finding is that the retinal blood vessel in people with Alzheimer’s disease is disrupted by up to 70%, and that harmful substances can pass through the veil and enter the retinal tissue in people with mild cognitive impairment compared to those with healthy cognition.

By looking at proteins in the retina, researchers found that in people with Alzheimer’s disease, vascular beta-amyloid deposits occur primarily in arterioles. This accumulation strengthens the blood vessels, which prevents the removal of harmful substances from the retina.

However, it was not clear whether the build-up of beta-amyloid caused the problem or whether damage to the arterioles caused the build-up.

For the first time, researchers have discovered a link between a disease called cerebral amyloid angiopathy, a blood vessel disease characterized by the accumulation of amyloid proteins in the small blood vessels of the brain, and a breakdown of the blood-retinal barrier.

Previously, this condition could only be diagnosed after death. With further research and improved imaging techniques, it may be possible to examine this in living patients.

While the findings are significant, they have not been replicated in living patients because all of the retinas examined in the lab were from deceased donors.

The lack of early diagnostic tests for Alzheimer’s disease is not only difficult to treat, but also difficult to design clinical trials.

There is also controversy surrounding the accelerated approval of two drugs in the past year: lecanumab and aducanumab.

While the results of the aducanumab study showed a reduction in the accumulation of beta-amyloid in the brain, it is not clear whether the drug can slow cognitive decline. As the disease progresses, it has been suggested that giving the drug earlier will give better results, but the inability to identify these patients cannot be included in clinical trials.

According to Dr. Theodore Strange, MD, associate chair of medicine and obstetrician at Staten Island University Hospital. Medical news today:

“This whole issue of tau protein and amyloid deposits is something that’s been explored for years, and we’re still trying to tackle it and get our hands on it.”

However, given the controversy surrounding amyloid deposits and their link to Alzheimer’s, some experts consider these developments promising.

According to Dr. Thomas Hanscom, an ophthalmologist and retina specialist at Providence St. John’s Health Center in Santa Monica, California. MNT “Current study adds to evidence supporting ‘amyloid theory’ of Alzheimer’s disease.”

Dr. Hanscom described recent reports of donamab’s effectiveness as “exciting.”

“This drug seems to reduce the development of Alzheimer’s disease, and this benefit is related to the removal of amyloid from the brain. This clinical research encourages the search for a reliable marker of amyloid in the retina. Several companies are trying to develop such a test,” he said.

One problem with developing a blood test for Alzheimer’s disease is that the disease primarily affects the brain, and the blood-brain barrier means that metabolites from the brain can enter the bloodstream. This makes it difficult to detect changes in the brain.

“[Biomarkers] It can help us with more treatment options, or causes, or early detection, especially if there is one. [are] Other diseases such as diabetes, early diabetes, dementia and the accumulation of these plaques[s]” said Dr. Strang.

According to Dr. Tariq Pascal, associate professor of psychiatry and neurology at the University of Pittsburgh MNT Looking at changes in the brain can be invasive and expensive.

“You have biomarkers of this amyloid pathology in patients’ cerebrospinal fluid and lumbar punctures that are measured by PET scans. These tests are expensive or difficult to perform,” he said.

However, vascular changes are common in people with Alzheimer’s disease, though It is not clear Whether it is caused by Alzheimer’s disease or is a precursor to it.

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