How many times have we heard the phrase “I am no longer the same person you met a few years ago.” And it is true, People change, but not always in the way they think. From a biological point of view, this question is very interesting, since the cells of the body are renewed over time, so each After a certain time, a person is almost completely renewed.
Renewal rates vary greatly depending on the fabric. While intestinal cells last only a few days, others can cycle for weeks, months or years, and some, like most neurons or eggs, will accompany us throughout our lives. However, during the renewal process, the newly created cells are not exactly the same as their predecessors because All living things suffer from a process called aging.
So far, 10 cellular mechanisms have been proposed that together could explain why mammals age. These 10 mechanisms, in turn, can divide into 3 groups depending on what part of the cell they affect: the inside of the cell, genetics or the cellular environment.
Our genome contains all the instructions for creating proteins that enable cellular metabolism. To do this, we have a specialized mechanism that can decipher the order of the molecules that make up the DNA chain and convert it into something that the cell can understand. Cell life depends on the integrity of the genome, therefore There are enzymes that are responsible for constantly correcting possible mutations.
. Like everything in biology, these tools are imperfect, so Errors accumulate over time.During cell division, DNA is duplicated and each copy is sent into the cell. With each division the probability of error increases, and gradually destabilization occurs in the genome. The consequence of this is that cellular metabolism is no longer as efficient, proteins are not produced correctly or it can even lead to premature cell death.
Another interesting aspect of aging is related to nuclear architecture. The position of certain nuclear proteins called laminins and DNA itself within the nucleus is important for the efficient operation of the genetic machinery. Its disruption is associated with the appearance of diseases that cause rapid aging, the so-called progeria. However, recent research shows that Aberrant prelaminin A, called progerin, also accumulates naturally with age.
Telomeres are structures located at the ends of chromosomes and made up of thousands of repeats of the nucleotides that make up DNA. In their normal function, they act as a defense during DNA replication and prevent chromosomes from joining together. Over time, telomeres shorten until they no longer perform their function and therefore, replication errors in the genome increase with age. These errors, of course, lead to the cells not working properly.
Telomere shortening causes the ends of chromosomes to fray.
And on the other hand, there is epigenetics, that is, modifications that occur to some components of DNA, but are not mutations. Changes can also be created in the chain itself, although without affecting the order of the DNA letters; in proteins that accompany DNA called histones; or in proteins that are responsible for unwinding DNA to read it, that is, for chromatin remodeling. It has been observed that promoting these chemical changes in model organisms can cause premature aging.
in the cell In addition to DNA, there are many other components that are also subject to wear and tear.. Sugars, lipids and proteins are affected reactive oxygen species, so-called ROS. ROS are substances that are created naturally during the process of obtaining cellular energy and which the body specifically controls. Despite the oxidation of cellular structures, ROS are essential for the proper functioning of the body.
, so there must be a balance between oxidizing and antioxidant substances. With age, mitochondrial deterioration of the enzymes responsible for achieving this balance again leads to aging.As you can see, Time affects the efficiency of cell mechanisms, the same thing happens with the elimination of worn-out or poorly produced proteins. Firstly, any protein that does not perform its function is immediately eliminated thanks to chaperones. But over time, the function of the component that tells chaperones that the protein should be broken down is lost. So proteins in poor condition accumulate in the cellwhich interferes with normal metabolism.
Finally, some studies have shown that aging cells lose the ability to detect and absorb nutrients from the environment, so they sometimes cannot produce all the energy they need to function. This hunger, added to the accumulated genetic faults, can lead the cell into a state known as senescence, i.e. latent state similar to support from TV. This is the last resort to prevent the cell from dying, but the accumulation of a large number of cells in this state in the tissue is a marker of aging.
Other age-related changes are associated with communication between cells, especially in the immune system. These errors can lead to chronic inflammatory condition, which causes more tissue damage. Additionally, old cells may no longer tell the body that they have reached their useful life and should be reabsorbed in a process known as autophagy.
The lipid structure of a lysosome, a cellular organelle containing enzymes inside that destroy all cellular components and provide autophagy.
All of these mechanisms age cells, most of which eventually die. They are replaced thanks to tissue stem cells.. Although age also affects stem cells, as a result of which the ability to regenerate tissue is lost.
This Top 10 mechanisms Aging processes can be listed as: Genomic instability, epigenetic changes, telomere attrition, protein instability, impairment of nutrient detection, loss of mitochondrial function, cellular senescence, altered intercellular communication, loss of autophagy, and stem cell depletion.
Methods are currently being explored improve natural DNA repair. By increasing the efficiency of this repair, cells will be able to correct errors in their genome and live longer. Except, There are epigenetic studies that could reverse these changes.. Finally, with the activation of a protein called telomeraseTelomere length can be increased and chromosomal aberrations reduced. However, genome modification is a very delicate matter, so These studies are still at a very early stage.. Any unwanted change may worsen the situation or cause uncontrolled cell division, leading to the appearance of cancer.
For this reason, pharmacological studies are being developed that try to look at other aspects of aging, especially in cellular. Early advances will make it possible to treat age-related diseases such as osteoarthritis, type II diabetes, Parkinson’s disease or Alzheimer’s disease. Other treatments based on stem cell replacement, immunotherapy or cardiac regeneration They are also increasingly becoming a reality. However, until they arrive, everything is in our hands. eat an appropriate diet, exercise in moderation, and take care of our tissues to keep them healthy.
That is, The Fountain of Eternal Youth is not located on some remote island, it is inside us, we just haven’t figured out how to get to it yet. The coming decades promise to be very interesting, thanks to the sharp minds dedicated to studying these processes, as understanding them and the ability to reverse them gets closer and closer.
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