Could Alzheimer’s disease (AD) be an autoimmune disorder? Some scientists suggest that it may very well be an autoimmune issue.
Approximately 6 million Americans suffer from AD currently, and projections suggest that 14 million Americans will suffer from Alzheimer’s by 2060. Thus, the search for a cure is heating up, and several controversies about the cause of AD have arisen.
Back in July of this year, Science magazine published a report regarding a 2006 research paper published in Nature. This report pinpointed a subtype of brain protein called beta-amyloid as the cause of Alzheimer’s disease. The Science magazine report suggests that the 2006 research paper used fabricated data.
That’s a serious accusation, especially since the U.S. FDA approved aducanumab an antibody-targeting beta-amyloid, as a treatment for Alzheimer’s. The FDA did this even though the supporting data were contradictory and incomplete. Some doctors argue that aducanumab should not have been approved.
Why are scientists having such difficulty with finding a cure? Finding the cause is a major obstacle to this quest.
Looking beyond the beta-amyloid connection
For many years, researchers have focused their efforts to discover new treatments for AD by focusing on the beta-amyloid connection. They have attempted to develop drugs that prevent the formation of these brain-damaging agglomerations. Unfortunately, this intense focus meant that scientists neglected other possible causes of AD.
However, the massive efforts to prevent the formation of beta-amyloid clumps has not produced an effective drug or therapy. Some researchers are finally looking beyond beta-amyloid clumps and pursuing other possibilities.
Research in Toronto, Canada is developing a new hypothesis on the cause of AD: that Alzheimer’s is an immune disorder within the brain.
The immune system is a collection of cells and molecules that work in harmony to help repair injuries and protect from foreign invaders. The immune system helps mend damaged tissues. When you have a viral or bacterial infection, the immune system helps in the fight against these microbial invaders.
The brain’s immune system works the same way. When you experience head trauma, the brain’s immune system activates to begin repairs. When bacteria are present in the brain, the immune system fights back.
Is Alzheimer’s disease an autoimmune disease?
The scientists in Toronto are investigating this question. They look at the beta-amyloid protein as a normal molecule within the brain’s immune system. They hypothesize that brain trauma occurs, or when bacteria are present in the brain, beta-amyloid contributes to the immune system response. This is the point at which difficulties may occur.
Fat molecules that occur in both the membranes of brain cells and membranes of bacteria have many similarities. Beta-amyloid cannot distinguish between the two types of cells and may attack healthy brain cells by mistake.
This leads to a chronic, progressive loss of brain cell function, which develops into dementia.
This approach to understanding AD is relatively new. There are many types of autoimmune diseases, such as rheumatoid arthritis, in which autoantibodies play a crucial role in the development of the disease, and for which steroid-based therapies can be effective. But these therapies will not work against Alzheimer’s disease.
While conventional therapies and drugs for autoimmune disorders may not work against AD, targeting other immune-regulating pathways in the brain may lead to new and effective treatments for Alzheimer’s.
Other theories of Alzheimer’s disease
In addition to this autoimmune hypothesis of Alzheimer’s, many other hypotheses are being developed. For example, some scientists believe that Alzheimer’s is a disease of tiny cellular structures called mitochondria — the energy factories in every brain cell. Mitochondria convert oxygen from the air we breathe and glucose from the food we eat into the energy required for remembering and thinking.
Some maintain that it results from a particular brain infection, with bacteria from the mouth often being suggested as the culprit. Still, others suggest that the disease may arise from abnormal handling of metals within the brain, possibly zinc, copper, or iron.
It is crucial that scientists are now pursuing other potential causes of Alzheimer’s disease. Currently, dementia affects more than 50 million people worldwide, with a new diagnosis being made every three seconds. Often, people living with Alzheimer’s disease are unable to recognize their own children or even their spouse of more than 50 years.
Alzheimer’s will only become a greater crisis unless we find the cause and cure. As a disease, AD has a huge impact on the patient, the patient’s family, and their economic status. The costs associated with AD will continue to skyrocket. We need a clearer understanding of the disease, its causes, and what may be an effective treatment.