Not removing 'brain garbage' contributes to the development of Alzheimer's

It is estimated that one person generates one kilo of waste per day. Imagine for a moment that we could not eliminate that waste. The garbage would accumulate in our homes. Living surrounded by garbage, in addition to great discomfort, would cause serious health problems.

That the nervous system is an extraordinary organ is nothing new. But with great power comes great responsibility. And it is that The nervous tissue, apart from being extraordinary, is extremely delicate. But don't panic, evolution has thought of this before anyone else and that is why it has provided us with a protective barrier that completely surrounds the nervous system: the blood-brain barrier.

The glymphatic system, the waste collector

The rest of the organs and tissues of our body have it easy. They have a waste management and disposal system that many cities would like. It is the call lymphatic system, a network of vessels (such as blood vessels) that eliminate everything that the cells do not need.

It is a waste disposal system that uses a unique network of channels that run through nervous tissue. This is good news because, in addition to the elimination of waste, the glymphatic system facilitates the distribution throughout the brain and spinal cord of substances necessary for proper functioning, such as glucose, lipids, amino acids, growth factors and neuromodulators – substances that control neuronal communication.

This tunnel system is formed by old acquaintances of the nervous system: astroglial cells or astrocytes. The name says it all: star-shaped cells. These small but valuable cells are distributed throughout the central nervous system, controlling that everything works correctly. With its multiple extensions, which give it its characteristic star-like appearance, they form terminal feet or widenings that form the tunnels of the glymphatic system.

There are many factors that determine whether the glymphatic system functions correctly, such as the circulatory system or the immune system. Therefore, our lifestyle, diseases and everything that affects astrocytes, such as inflammation, will have negative effects on the glymphatic system. One of the most important is sleep. Interestingly, the glymphatic system functions mainly when we sleep and stops working, to a large extent, when we are awake.

In addition, this system is more efficient and productive when the heart is beating strongly, because this way the blood flows, the body relaxes, and the brain enjoys a restful sleep. It makes sense: Take advantage of the hours of sleep to remove brain garbage. What's more, some scientific studies affirm that the restorative nature of sleep is largely due to the activity of the glymphatic system.

But not everything is good news, and the glymphatic system, like so many other structures, also deteriorates as a result of aging. Or, put another way, As we get older our nervous system loses its ability to take out the trash.

Protein waste accumulated in Alzheimer's and other diseases

One of the biggest risk factors for suffering from a neurodegenerative disease is the aging. Therefore, failure of the glymphatic system could contribute to the accumulation of waste in the brain as we age.

This is what happens in Alzheimer's. This disease is characterized by the progressive deterioration of cognitive - information processing capacity - and functional capacity along with behavioral changes, which usually appears around the age of 65. In the brain of patients, deposits of poorly folded proteins (beta amyloid and tau) appear that, since they cannot be eliminated correctly, accumulate., affecting the proper functioning of the nervous system.

In this sense, a recent study carried out in animal models of Alzheimer's disease indicates that By improving the functioning of the glymphatic system, more efficient drugs could be obtained for its treatment.. There is little point in cleaning the house every day if we don't take out the trash afterwards. That is, no matter how effective the therapies aimed at eliminating protein plaques accumulated in the brain are, if the pipes are clogged the treatment will be of little use.

But not only Alzheimer's. The scientists who discovered the glymphatic system a few years ago, Maiken Nedergaard and Steven A. Goldman, hypothesized that Glymphatic insufficiency is common in the development of other diseases such as Parkinson's, Huntington's disease, multiple system atrophies and frontotemporal dementia.

Given that optimal functionality of the glymphatic system occurs when we sleep and that these diseases are strongly correlated with significant sleep disturbances, It is believed that poor sleep can contribute to the glymphatic system not functioning properly, contributing to the appearance of these diseases.

The English playwright Thomas Dekker said that “Sleep is the golden chain that unites health and our bodies”. After reading this article, you have enough information to answer those who say that “sleeping makes us lose time in our lives.” Of course, everything in its proper measure.

José A. Morales García Professor and scientific researcher in Neuroscience at the UComplutense University of Madrid

This article has been provided by The Conversation