Can Light Therapy Reverse Alzheimer’s?

One of the greatest challenges for researchers in the past 50 years has been the battle against Alzheimer’s, the degenerative disease that affects the memory center of the brain. There are countless medical studies and nearly $500 million spent every year on reversing or curing this affliction, but the majority of drugs that have been produced have limited or inconsistent results.

However, a new approach from a handful of brilliant researchers at Massachusetts Institute of Technology may offer hope in this challenging and frustrating field of study. Since drugs haven’t shown themselves to be an effective solution, they turned to light therapy – a seemingly simple solution to one of the great mysteries of human health. The question is… can light therapy actually cure or reverse Alzheimer’s?

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Short Answer: Positive results have been shown in mice during lab testing, but the efficacy on humans has yet to be proven.

The Science of Forgetting

Only someone who has had direct contact with someone suffering from Alzheimer’s can truly understand the anguish that this disease can cause, both in the patient and their loved ones. Beginning in the form of “senior moments” or a habit of being a bit more forgetful, this disease can progress at very different rates, from a matter of months to decades. Regardless of the speed of decline, little by little, the brain’s ability to recall memories is compromised.

Our brains are dependent on roughly 100 billion neurons to carry out the complex task of cognition, and those neurons function by connecting tiny chunks of information together – whether it is the demands of the muscles to walk and talk, the summoning of memories, or the most basic reactions to external stimuli. Alzheimer’s is a truly devastating disease because it slowly breaks down the ability of the brain to make all the connections it needs to function normally.

Over time, for Alzheimer’s patients, there is a significant deposition of abnormal proteins in the brain, primarily caused by “tau tangles” and beta-amyloid plaque. These proteins cause neurons to stop working properly, losing connection to other neurons and eventually dying, unable to be revived. When these neuronal connections break down, it becomes more difficult to recollect things, from simple things like where you left your shoes to tragic absences like the name or face of a loved one… or even what happened a few moments earlier.

Most of this damage is initially seen in the hippocampus, the part of the brain responsible for memory. However, this disease can spread to other parts of the brain, causing atrophy and shrinkage. A brain that has completely succumbed to Alzheimer’s disease has significantly larger ventricles (spaces for fluid in the brain) and the cortex appears to have entirely collapsed.

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Many of the proposed drugs to reverse or cure Alzheimer’s has targeted one or both of there protein-depositing culprits – tau tangles and amyloid plaques – but this has failed to produce a reproducible and reliable remedy for this disease. Fortunately, there may be a new and revolutionary approach, thanks to Dr. Li-Hue Tsai and his team at MIT.

LED Light Therapy for Alzheimer’s

After decades of research, something as simple as flashing a light in the eyes of an Alzheimer’s patient sounds almost laughable, but the team at MIT has applied their theory on mice with some surprising results. By subjecting specialized mice (genetically engineered to have Alzheimer’s-like damage in their brain) to rapid strobe pulses of LED light (40 flickers per second), they were able to see measurable reduction in the beta amyloid plaque that is believed to cause protein deposition and neuronal death in the brain.

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As they discovered, the flashing light actually caused an increase in brain activity, specifically in defensive cells in the brain called microglia, which act as scavengers. Microglia are already present as a part of our immune system, but are stimulated or activated by light, which essentially recruits these cells to the area subjected to this LED exposure. Microglia are programmed to eat, dissolve or eliminate harmful pathogens that may attack the brain, and in the case of this study, they attacked the beta amyloid plaque.

Interestingly enough, in Alzheimer’s patients, these microglia tend to behave in the opposite way, releasing toxins that actually damage healthy cells and speed the process of deterioration. However, when subjected to this light therapy (technically known as gamma oscillation, a practice within the field of optogenetics), the microglia underwent almost immediate physiological changes and began functioning as they do in a healthy brain.

Initially, the study focused on the visual cortex, physically flashing the light at the mice for one hour at a time. Within 12-24 hours, there was a measurable decrease of amyloid plaque in the areas of the brain that control vision. When the hippocampus – the memory center – was directly stimulated (not visually) with the same rapid pulse, a decrease in beta amyloid plaques was also seen. The two exciting findings of the study are that, in some form, gamma oscillation through LED light therapy not only induces microglia behavior to clear out beta amyloid plaque and its proteins, but also cause neurons to stop producing as much plaque in the first place.

There are some issues that still need to be resolved, such as the rather rapid return of protein depositions following this sort of treatment, although consistent exposure to the therapy does appear to slow down the ability of the beta amyloid plaques to recover and re-release their proteins. Secondly, it is unknown whether this “meddling” in the brain has any marked behavioral changes in the mice, which would be more difficult to spot in their relatively simplistic brain, as opposed to the most complex noggin on the planets – human beings.

Either way, this new research is one of the most exciting new developments in the field of Alzheimer’s research, and due to its non-invasive and relatively inexpensive application, it is expected to be tested on humans in the very near future. This could signal a massive shift in what we know about Alzheimer’s disease and dementia, some form of which affects 50 million people around the world.

References:

  1. Unique Visual Stimulation May Be New Treatment For Alzheimer’s – Massachusetts Institute of Technology
  2. British Broadcasting Corporation (BBC.com)
  3. More Brain Changes – Alzheimer’s Association
  4. World Alzheimer Report 2015
The short URL of the present article is: http://sciabc.us/ut4vR
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