Alzheimer’s Disease: Researchers have found a new piece of the puzzle

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Dementia causes painful memory loss problems to those who are affected by it along with their friends and families. Chances are that someone you know in their 60s or older has memory problems that will or have already progressed into more serious cognitive problems. This devastating form of dementia is called Alzheimer’s disease, and is rapidly increasing as our life expectancy increases and currently has no cure. A new study might hold the key to better understanding why people get this heartbreaking disease, and provide insights into how to prevent it.

Alzheimer’s disease (AD) is a costly and emotionally taxing disease for those who have it and for their friends and family. With no current cure, most research today is focused on understanding this complex brain disease.  It is the most common cause of dementia, which starts with memory loss and can eventually lead to the loss of the ability to do every day tasks. 13% of people over 65 and 33% of people over 85 have developed Alzheimer’s and it is the sixth leading cause of death in the United States.

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As the population continues to age and live longer than the generation before it, Alzheimer’s becomes more common continues to consume more money in health care. Current research is trying to understand what happens in the brain that causes loss of memory and basic cognitive function so a cure or treatment can be found. Currently, there are treatments that delay or slow down the progression of the disease, but none that completely get rid of it or prevent it. Finding a cure or preventative measure for Alzheimer’s will dramatically decrease the cost of care for older people and reduce such devastating losses.

What we know about Alzheimer’s disease

The cause of AD and its progression are not well understood. The cells in the brain are damaged or killed, preventing the brain from telling the rest of the body what to do. As the disease spreads through the brain, the symptoms become worse, eventually making it impossible to do simple everyday tasks or hold conversations.

Plaques called beta amyloids are an indicator of AD. Beta amyloids plaques sometimes build up inside the nerve cells in the brain preventing them from connecting to send messages through the body. Another common indicator of AD is when proteins, called tau proteins, in the brain cells become tangled and build up inside the cell. Tau tangles and plaques usually initially develop in the memory region of the brain, which is why memory loss is the first symptom of AD.

Source. Beta-amyloids build up between nerve cells. As shown they can get in the way of the connections between cells so they can’t communicate to the rest of the body.

Scientists think that tangles and plaques play a role in blocking the communication between nerve cells, and the death of these cells are what causes memory loss. However, some people with tau tangles and plaques never develop symptoms of the disease, like memory loss. This has been a big challenge in the field, as scientists can conclude that plaques and tangles are not the cause of the disease, and something else must be occurring. The following video does a great job of visually explaining what happens inside the brain when Alzheimer’s disease develops.

A recent study may have found which protein causes Alzheimer’s disease

A new study from Harvard has shown that a stress response in the brain may be the key to the development of AD. A protein called REST (repressor element 1 silencing transcription factor) is a protein that regulates the expression of genes and is most commonly found in the brains of fetuses.

Genes are contained within DNA and tell proteins in the body what to do. Repressor proteins, like REST, interfere with the DNA structure and block the genes from telling other proteins in the body what to do. A recent Harvard study found that REST is the most active gene regulating protein in healthy older brains. The group now has reason to believe that REST is expressed in fetal brains and older brains to protect them because they encounter the most stress during those periods of time. REST appears to switch off genes that promote cell death.  They protect your brain from this:

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In the study, the researchers (Yankner et al.) found that brains of young adults (20-35 years old) had very low levels of REST, and brains of older people (73-106) without AD had very high levels of it. They also found that as age increases, levels of REST also increase unless the patient develops dementia.

Brains of the patients with no symptoms that had plaques and tangles had 3 times more REST than those who did have symptoms. In addition, people that had mild cognitive problems had significantly more REST than those with AD. Most of the REST was found to be in the region of the brain that is responsible for learning, memory, and planning (the prefrontal cortex hippocampus). One third of people whose brains have plaques and tau tangles do not develop symptoms of AD, and the presence of REST could explain why.

These results demonstrate an obvious connection between REST and AD, however, it is too early to tell if REST cause or consequence. High levels of REST in older brains indicates that they are healthy, whereas low levels of REST in older brains indicates dementia, but it is unknown if dementia results from the lack of REST or causes lower levels of REST. More research is needed to determine what the relationship is between the two.

Understanding this relationship could lead to the development of treatments for AD. Treatment for AD would result in better quality of life for the population as we age, and would translate into huge savings in medical costs – both for families enduring it and for the economy. I hope to hear more about positively life-changing discoveries in science!

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Thanks for reading, and cheers to your literal brain!

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References:

REST and stress resistance in ageing and Alzheimer/'s disease. T Lu, L Aron, J Zullo, Y Pan, H Kim, Y Chen, TH Yang, et al.  Nature, 2014