Expert says Alzheimer’s may not actually be a brain disease: ScienceAlert


The pursuit of a cure for Alzheimer’s disease The disease has become an increasingly competitive and controversial pursuit with recent years having seen several important controversies.

In July 2022, Sciences magazine I mentioned that the key 2006 research paper published in the prestigious journal temper naturewhich identified a subtype of a brain protein called beta-amyloid as a cause of Alzheimer’s disease, may be based on fabricated data.


One year ago, in June 2021, it was The US Food and Drug Administration approved aducanumaba beta-amyloid antibody, as a treatment for Alzheimer’s disease, although data supporting its use have been incomplete and contradictory.

Some doctors believe aducanumab should never have been approved, while others feel it should be given a chance.

With millions of people in need of effective treatment, why are researchers still floundering in this search for a cure for what is arguably one of the most important diseases facing humanity?


Escape from beta-amyloid rut

For years, scientists have been focused on trying to devise new treatments for Alzheimer’s disease By preventing the formation of clumps of this mysterious protein that destroys the brain It is called beta-amyloid.

Indeed, it can be argued that we scientists have put ourselves in an intellectual turmoil that focuses almost exclusively on this approach, often ignoring or even ignoring other potential explanations.

Unfortunately, this dedication to studying abnormal protein clumps has not translated into a beneficial drug or treatment. The need for a new “outside the group” way of thinking about Alzheimer’s disease is emerging as a top priority in brain science.

My lab at the Krembil Brain Institute, part of the University Health Network in Toronto, is working on creating New theory of Alzheimer’s disease.

Based on the past 30 years of research, we no longer think of Alzheimer’s as a disease that primarily affects the brain. Instead, we think that Alzheimer’s disease is basically A disorder of the immune system in the brain.

The immune system, found in every organ in the body, is a collection of cells and molecules that work in concert to help repair infections and protect against foreign invaders.

When a person stumbles and falls, the immune system helps repair damaged tissue. When someone suffers from a viral or bacterial infection, the immune system helps fight these invading microbes.

Exactly the same processes are found in the brain. When there is head trauma, the brain’s immune system begins to help repair. When bacteria are present in the brain, the immune system is there to respond.

Alzheimer’s disease is an autoimmune disease

We believe beta-amyloid is not an abnormally produced protein, but rather a naturally occurring molecule that is part of the brain’s immune system. It’s supposed to be there.

When brain trauma occurs or when bacteria are present in the brain, beta-amyloid is a major contributor to the brain’s overall immune response. Here the problem begins.

Because of the striking similarity between the lipid molecules that make up the membranes of bacteria and the membranes of brain cells, beta-amyloid is unable to distinguish between invading bacteria and host brain cells, and mistakenly attacks the brain cells it is supposed to be. protection.

This leads to a chronic and gradual loss of brain cell function, which eventually culminates in dementia – all because the body’s immune system cannot differentiate between bacteria and brain cells.

When Alzheimer’s disease is viewed as a false attack by the brain’s immune system on the very organ it is supposed to defend, Alzheimer’s appears as an autoimmune disease.

There are many types of autoimmune diseases, such as rheumatoid arthritis, in which autoantibodies play an important role in disease progression, and for which steroid-based therapies can be effective. But these treatments will not work against Alzheimer’s disease.

The brain is a very special and special organ, known as The most complex structure in the universe. In our model of Alzheimer’s disease, beta-amyloid helps protect and boost our immune system, but unfortunately, it also plays a central role in the autoimmune process that we think may lead to the development of Alzheimer’s disease.

Although drugs traditionally used in the treatment of autoimmune diseases may not work against Alzheimer’s disease, we strongly believe that targeting other immune-regulating pathways in the brain will lead to new and effective treatments for the disease.

Other theories about the disease

In addition to the autoimmune theory of Alzheimer’s disease, many new and diverse theories are emerging. For example, some scholars believe that Alzheimer’s disease is a disease of tiny cellular structures called mitochondria Energy factories in every brain cell.

Mitochondria convert oxygen from the air we breathe and glucose from the food we eat into energy for remembering and thinking.

Some see it as the end result of Certain brain infectionwith Bacteria from the mouth is often suggested as the culprit. Still others suggest that the disease may arise from Abnormal processing of minerals in the brainMaybe zinc, copper, or iron.

It is a pleasure to see New thinking about this old disease. Dementia currently affects more than 50 million people worldwide, and a new diagnosis is made every three seconds. Often, people with Alzheimer’s disease cannot recognize their children or even their wives for more than 50 years.

Alzheimer’s disease is a public health crisis in need of innovative ideas and new direction.

For the well-being of people and families with dementia, for the social and economic impact on an already stressed health care system and to deal with the ever-increasing costs and demands of dementia, we need to better understand Alzheimer’s disease and its causes, and what we can do to treat it and help people and families who suffer from dementia. live with it.

Donald WeaverProfessor of Chemistry and Director of the Krembil Research Institute, University Health Network, University of Toronto

This article has been republished from Conversation Under a Creative Commons License. Read the original article.


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