Three main theories
What causes brain aging?
Lyubov Sokovikova, Hi-News
The reasons why the most complex organ of the human body ages
Aging of the brain cannot be seen just by looking in the mirror. The brain changes in an imperceptible but measurable way as we get older. When a person is born, his brain contains many neurons, but the number of connections between them is insignificant. As you get older, a large number of neural connections are formed, and with age they begin to weaken. But what exactly causes these changes? Today, there are many different theories about why neurons and cells in general age. We offer you to familiarize yourself with the three most well-known theories about the causes of brain aging.
DNA damage
Changes in gene expression–the process by which hereditary information from a gene (DNA nucleotide sequence) is converted into RNA or protein–may play a role in neuronal aging. The genes involved in synaptic plasticity are less active in the brains of older people than in the brains of young people. In these genes, as a rule, there are more signs of DNA damage that accumulate during life and contribute to the aging processes in the brain and body.
Synaptic plasticity is the main mechanism by which the phenomenon of memory and learning is realized.
Studies on humans and rodents show that damage contributes to age-related memory loss and cognitive impairment. Rodents with more damage perform worse on memory tests, and people with mild cognitive impairment and Alzheimer's disease have more signs of DNA damage compared to healthy people. Moreover, the energy needs of the brain can make the organ more vulnerable than other tissues to the metabolic changes that occur with aging.
Violation in the work of the own immunity of the central nervous system
Disorders in the immune system often occur against the background of metabolic changes that are observed with aging. Microglia – a kind of own immunity of the central nervous system – performs many important tasks: protects against pathogenic microorganisms, cleanses cells and helps maintain and reconstruct synapses. These inflammatory reactions are protective, but prolonged inflammation is harmful to brain health. With age, microglia become more reactive, increasing the inflammatory response in the brain and simultaneously reducing the production of beneficial anti-inflammatory molecules. Studies in mice show that excessive microglia activity can impair cognitive abilities.
Cognitive abilities are called higher brain functions, such as speech, thinking, attention, perception, etc.
Violation of protein processing
In the process of destruction, cells recycle damaged proteins and molecules. However, this process is not perfect, and over time, damaged molecules can accumulate in cells and interfere with their normal operation. So, in Alzheimer's disease, proteins accumulate inside brain cells. The accumulation of proteins and other cellular components also contributes to cellular degeneration in a healthy brain. Although some changes occurring in the brain are a normal, inevitable part of the aging process, this does not mean that we cannot control them. For example, poor cardiovascular health probably contributes to the changes observed in the aging brain. On the other hand, things that are good for the heart – proper nutrition, exercise, and stress reduction – can also benefit your brain as you age.
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