the reason why infections make us age faster
For every infection from which our immune system protects us, we not only become somewhat tired, but, above all, we grow old. Recent research suggests that biological age may be much older than natural age in people who have had multiple viral infections or are suffering from chronic infection.
In these cases, it is not uncommon for a person with a chronological age (as stated on their identity document) of 40 years old to have an immune system typical of someone 60 years old, which can profoundly impact their quality of life and the functioning of their immune system. Immune system Your immune system.
What is this for? How can a virus make us grow old? To understand this, we must start by remembering that the genetic information we inherit from our parents is stored in our chromosomes, which are superpacked DNA structures with four arms arranged in the form of chromosomes. protective helmets called telomeres.
Division implies wear and tear
The word telomere is of Greek origin and literally means “end part”. Its function is to prevent chromosomes from breaking or being damaged because they are weaker at the ends. It’s as if chromosomes were made of wool: without these protective helmets, they risk fraying and falling apart.
The cells of our body are not the same when we are born and when we die: throughout life they are renewed through successive divisions, in which two identical daughter cells are formed from one cell.
Each cell division entails a slight wear and tear of telomeres, which become smaller each time, which we know in jargon as telomere shortening. After a certain number of divisions, they are so small that they cannot perform their protective function and the chromosome begins to wear out and lose its structure. When this happens, cells lose their ability to divide and perform their functions.
In a sense, telomeres act like a cellular clock, able to measure how many times a cell can divide. In fact, it’s normal for older people to have more worn-out telomeres than younger people. However, telomeres shorten not only with age, but also under the influence of other factors such as ethnicity, gender, stress, diet and exposure to certain diseases.
Infections affect telomere size
When immune system cells come into contact with a harmful microorganism, a process of massive division and multiplication begins until they form a large population sufficient to destroy the invader.
This means that each infectious process generates a cycle of massive divisions of immune cells with subsequent wear and tear of their telomeres and an increase in the likelihood of earlier entry into the so-called state of immunosenescence, that is, the aging of the immune system. .
The more infections we encounter in our lives, the more the telomeres of the cells that protect us shorten and the more our immune system ages. In fact, experts talk about “viral aging.”
In particular, studies involving patients infected with viruses such as HIV, Epstein-Barr virus (which causes mononucleosis), and hepatitis C virus, among others, have shown shortening of the immune system’s telomeres. Additionally, patients who have had more severe illness due to Covid-19 have recently been shown to experience telomere shortening.
Therefore, as we mentioned at the outset, biological age can be much older than natural age in people who have had multiple infections or are faced with chronic infection.
Immune aging and its consequences
As telomeres shorten and the immune system ages, cells lose their ability to protect us from infections, so the risk of contracting infectious diseases increases.
This is why older people respond less well to infections and, more worryingly, to vaccines, since a vaccine requires a properly functioning immune system for it to work.
There are also indications that telomere shortening prevents the regeneration of damaged tissue after infection through cell division, leading to complications in a significant proportion of patients or an increased risk of developing other pathologies.
More respiratory infections, cancer and autoimmune diseases
The consequences of immunoaging are numerous: it is associated with greater susceptibility to respiratory and urinary infections, infective endocarditis (infection of the endocardium, the membrane lining the chambers of the heart), and sepsis (the presence of bacteria in the blood). , as well as cancer, Alzheimer’s disease and autoimmune diseases. Autoimmune diseases are diseases in which the immune system attacks cells in our own body without causing harm: it seems logical to think that a defective immune system is more likely to “make a mistake” and attack those it shouldn’t.
There is no doubt that infections cause accelerated aging of the immune system, which leads to a greater susceptibility to both infectious diseases and the development of other pathologies.
This relationship between infections and aging through telomere wear requires more in-depth research to try to anticipate and develop strategies to alleviate telomere wear.