Since we are born, we learn that getting old is just another constant in life.
Like the sun sinking at the end of the day, like our weights failing down to gravity, we -ourselves- will inevitably fall into all the disability, tiredness, and unhealthy life imposed by the inevitable aging.
We usually wouldn’t question the truth of aging we saw on our grandparents’ faces and backs when we arrived in the world. We rarely ask how aging works or is it something we can even stop.
A new human, nevertheless, is not anymore accepting inevitabilities. Defying gravity, Going to outer space, and taking aging for granted is not anymore an unquestionable matter.
In our endeavor towards fighting aging as a recognized disease, we must first understand how it works and why it happens.
The first idea that comes thinking about why we age is that our organs get old as our clothes and machines do. The tear and wear lead to regular deterioration, skin gets bail, muscles weaken, and nerves blunder.
We think overworking, overusing our body cells as we live leads naturally to aging. Yet, we ignore that our bodies are equipped with regenerative engines, repair engines, and growth mechanisms that no man-made machine ever had.
We have internal machines that accompany us from babyhood, over puberty towards youth, and until getting old. Why and how these machines gave up, how they get ill and start to fail in doing their regeneration and repair process. Then we think, do we inevitably have to age?
This article will take us through a journey between nine causes of aging, known as the hallmark of aging. A glimpse on these types of aging will make you briefly understand the dynamics of your body, the effects of aging on body systems, and the consequences of adopting an unhealthy diet and lifestyle on accelerating your aging process, and if a new human would be able to conquer and reverse the aging process of his body.
Mankind thinks only of living because he is dying, and it is only in dying that he gains his freedom to live
1. Body-Apocalypse of the undying cells
Simply said, Cells are meant to die so we can live.
That is the natural process that keeps our bodies young; old cells ceasing to exist and new fresh cells replacing them, in a sought eternal process.
Why are we not eternal, though?
Because some cells simply refuse to die.
Cells can get damaged “killed” by external factors like harmful sun exposure, smoking or unhealthy food, or even pollution. They could also just die naturally. Our bodies can handle a dead cell. But the undying cells will hinder the whole regeneration process. These cells, also known as senescent cells, become both cancerous and infectious, they transmit their “zombie” disease to neighboring cells. They appear as a bug or a mutational error in cells, and then they accumulate in the body as we age (1).
Senescent cells are clear signs of aging. They expand in a destructive process to damage other cells and spread harmful inflammation over the body, accelerating aging and age-related diseases (2).
Senolytics to cure zombies..
In a lab experiment, scientists observed the process of turning a young mouse into an aging one just by injecting it with these senescent cells. Now trials are ongoing to develop drugs known as senolytics, which are assigned with a noble job to eliminate the undying cells and help expand a longer healthy life span. The study proved that injecting senescent cells causes aging symptoms like physical dysfunction, and senolytics can reverse these impacts in old mice (3).
2. Growing is a self-destructive process
Misfortunes come of themselves.
Cells-division is the primary process for growing and cell regeneration, but it is a process that comes with a cost. It is a long-term self-destructive process that inevitably comes to an end, literally the end of a telomere. Or it might not?
…but what is a telomere?
Well, let’s first introduce our chromosomes…
Chromosomes are the basic structure of a human cell’s brain. They contain a DNA wrapped in proteins instructing the genetic code of a cell, which governs what a cell shall grow to be and how it might function (a cell’s brain!).
When chromosomes become unstable, they directly endanger body cells, condemning them to irreparable damage or killing them off (insane brain!).
Our young bodies assign chromosome protectors in each cell. These are the telomeres.
Telomeres are nothing but some protective cabs protecting the DNA ends.
The only problem is, for our bodies to grow up, chromosomes keep on multiplying, and with each cell division, the telomere of DNA becomes shorter until, at some point, they wear entirely off, leaving the chromosome unprotected. When an unprotected chromosome multiplies for another time, it gets still shorter but this time losing parts of the DNA itself, copying falsy information to the new cells.
Thus, every attempt of our chromosomes to help the growth and rebuild of the body results in risking its own safety towards a shorter or a completely weared-out telomere, losing vital DNA information from the unprotected ends of a DNA, driving the chromosomes into an unstable state which shall then endanger its cell (4).
Tolermer length is a natural result of natural cell replication during growing and is also influenced by oxidative stress and inflammation acquired from the body’s environment (5). Also, the rate of telomere shortening could be influenced by some lifestyle and metabolism. Individuals may have excessive or trivial shortening rates that translate into an accelerated or slowed aging process (6).
The Nobel-Winning Telomerase..
Back in 2009, three scientists have won the Nobel Prize for physiology for their efforts in identifying the telomerase enzyme, a unique DNA sequence in the telomeres that protect the chromosomes from degradation (7). Further studies tried to indicate that some nutrients and natural compounds proved potent telemesare actuators that could be used to treat aging and aging-related diseases if proven effective in human clinical trials (8).
3. Cells malfunction from irreparable DNA Errors
When observing old body tissues, scientists found that all cells of these tissues share a common defect of containing DNA errors (9).
A DNA in a cell is more like a program code that instructs the cells’ behavior. When cells grow or multiply, The genetic code in a DNA is copied and pasted in a new cell as an instruction manual to manage how the cell shall operate.
Human errors also happen in DNA codes similarly as in software codes, random mutations can simply cause a faulty code replication, or what we can call genetic damage. In the long term, wrong instructions given to the cell will cause it to be dysfunctional, damaged, broken or even cancerous.
DNA errors aren’t yet the problem, it is rather quite normal to expect an average of 160,000 DNA injuries per cell per day (10). Bug fixing too is a naturally evolved function in our bodies. DNA fixing enzymes work around the hour to repair faulty DNAs and damaged cells. Instead, the problem is when our bodies fail to speed up the repair process, leaving up numerous irreparable DNA errors and genetically damaged cells. That is when our cells start to irreversibly age when a cell loses hope for a DNA fix.
The genetic disruption of DNA repair pathways in mice has proven to be linked to premature aging in mice. It is scientifically a powerful argument to claim that DNA damage in mammalian tissues is a cause of aging (11).
We have already gone a great deal in understanding the different mechanisms our bodies used to repair DNA errors and the most active enzymes responsible for the task. We can clearly relate cells malfunction to how aging works. Yet we have to figure out completely how to prevent faulty DNA copies or to treat the repair pathway of a DNA when it gets impaired.
He’s made of staples an broken bones
Bruises from chapters
4. Cells losing their identity
A faulty epigenetic moderation is usually not easy to recognize. When it happens, organs start to lose their full functionality. Yet, we do not usually recognize our full functionality, as we are mostly not using our bodies’ full potential, especially when we lack exercises and overall body simulations. In another way, we do not recognize the physical changes during aging process.
Aging and cancers are the most common results of faulty epigenetic moderation. While young cells run a healthy epigenetic moderation that represses harmful genes and promotes genes involved in cell cycle control and DNA repair. On the contrary, aging cells suffer a disorder in epigenetic modifications leading to silencing healthy genes and promote pathways involved in cellular senescence (12).
You peel back the layers
And get down to the inside
But sometimes you loose sight
Of what it was you were trying to find
5. Cells not recognizing nutrients anymore
Our cells are pretty much intelligent with nutrients, ironically more intelligent than us.
They are programmed to sense and measure what they get as food, detect the amount of fat and glucose, and then adjust how they will process the nutrients in a balanced healthy way.
As we age, we become more intolerant to what we eat, suffering food problems that we normally digest at younger ages. Our smart young cells get tired. Their senses become less accurate in recognizing fats and sugar levels and less sensitive to rising blood sugar (insulin). Ineffective nutrient processing leads to faulty digestion, resulting finally in acute metabolism, age-related diseases like diabetes, and similar aging signs.
Several theories suggest that practices such as calorie restrictions (fasting) are strongly related to slowing down aging symptoms resulting from metabolic degradation of the body (13).
6. Aging cells failing to renew control proteins
He who heeds not the lost shoe-nail, will soon lose the horse.
Alzheimer’s disease results from losses of nerve cells. Scientists suspect that proteins like beta-amyloid and their aggregation in the brain to be the reasons behind this nerve cell damage (14).
Proteins have a novel duty of carrying control signals around to manage the functions of the cells. These proteins get tired and old themselves, becoming cells’ wastes, which is normal for a young body. Yet not for our old bodies, which at that age would fail to renew or eliminate these waste proteins as they used to do earlier.
It is a dangerous downhill way, young body cells can replace unusable proteins, but once the cells get older, they lose this ability, leaving behind stacks of harmful proteins which become toxic to the body cells itself and affect the functions of the cells leading them to further deterioration and overall aging.
7. Exhausted stem cells failing to renew tissues
Stem Cells are the joker of cells. They can very well explain how aging works in human.
In contrast to other cell types, they can simply alter their epigenetic settings and switch the function they intend to do. They can turn into brain cells, skin cells, or whatever else type required by the body.
Tissue’s renewal process is majorly dependent on stem cells, no matter in which organ, when tissues are damaged, stem cells step in to regenerate fresh cells and restore the organ function. Stem cells work in away to hold back the aging process.
We used to heal up so quickly as kids. The more we get older, the slower we heal. That is an exhausted stem cell system reducing body capacity to renew or replace damaged cells. While we age, different drawbacks occur to the body and exhaust these stem cells. Like discussed earlier, problems like telomere shortening or information from senescent cells, resulting in a body disabled to compensate for its losses and recover lost functions.
The development of stem cells technology is promising high potentials in treating aging. Besides the ethically skeptical embryonic stem cells, studies using induced stem cells have shown potential in treating cardiac disease at both laboratory scales and in mouse models (15).
8. Cells losing internal communication
One can imagine the function of our body cells as the function of human society. The quality of communication between the society members decides the progress of the whole community. A group of people who cannot interact, exchange information, and organize themselves fails as a society. Similarly, the cell structure is successful only because of a strong communication network that manages to build a symmetric face, a continuous cycle of the bloodstream, or most importantly, a 24/7 immune system to protect the whole body unit.
Studies show that the cell’s communication abilities decline with age because of the loss of receptors or the communication channel (signaling pathways) (16). As we age, some cells get damaged, turning into senescent cells, spreading in inflammation across the body. They become a communication disruption within the body, blocking or missing vital signals transmitted across the body. Leading to dysfunctional cells, immune dangers, and even further spread of senescent cells
9. Our powerhouses brake down
Mitochondria are known as the powerhouses of our body cells. They are essential organelle -subunit of a cell- which exists in all body cells, except for red body cells.
They are majorly responsible for turning food molecules into chemical energy to power the body cells. They also play essential roles in our bodies, such as heat production, immune signaling, hormone signaling and metabolism regulation.
Mitochondria typically have a risky structure within. They differ from any other cell subunits in that they have their own kind of DNA with fewer repair pathways than any typical nuclear DNA. That means that DNA disorders resulting from defects in enzymes may occur more often than usual in Mitochondria.
Inherited mutations are usually responsible for DNA disorders in Mitochondria, and some gene therapy procedures were already performed on embryos to swap defective mitochondrial DNAs (17). The harmful mutations could also be acquired from environments like infections or drugs. Some vitamins and enzymes could be clinically developed to help regulate some types of dysfunctional mitochondria (18).
We tend to believe in the inevitability of aging as we compare our bodies to our man-made machines that deteriorate, damage, and die inevitably. We instead need to think of aging as we think of a headache, astigmatism, or even a trimmed nail as a remediable, avoidable & reversible process.
We can now summarize the main mechanisms of how aging works, the primary actuators of aging, and almost the pathways to reverse them:
- The undying cells block the regenerative process and become toxic to other cells. We need to improve our bodies’ abilities to identify and kill these cells before expanding to an irreparable state.
- The process of shorting the telomeres would lead inevitably to chromosomal instability, and consequently, massive damage in cells. Yet, we can work on enzyme actuators that would ideally protect chromosomes from degradation, slowing or stopping the telomeres’ shorting.
- Repairing cells with faulty DNA is an essential mechanism in our body. When it fails, it endangers primary functions and promotes aging. Nevertheless, we could influence the enzymes responsible for the repair pathways of DNAs, keeping our bodies capable and young for longer.
- Failures in epigenetic modifications result in dysfunctional body organs. A process that still could be influenced by genetic therapy.
- Aging cells are more vulnerable to bad diets. They fail in processing fats and sugars and allow a series of metabolic diseases. Adopting a healthy lifestyle and diet from a younger age could be a preventive approach to avoid most aging-related diseases.
- The renewal of chromosomes control-proteins slows down as we age. The loss of cell function is a consequence of failing to renew or remove bulks of toxic proteins surrounding our DNA sequences.
- Losing stem cell capacity is a significant highlight of aging. However, a promising future is awaiting us with the rapid development of stem cell technology to deliver external sources to keep our stem cell production coming for a longer healthy life span.
- Disruptions on the cell signaling pathway put the whole body in a vulnerable state, losing parts of its proper functionality and the overall protection of the immune system. Fixing the cells’ communication pathways and getting rid of senescent cells obstructing a healthy signaling system in the body is a way to prevent aging diseases.
- Finally, when our powerhouses, the Mitochondrion, fail due to inherited or acquired mutations, all our body cells would go in an irreversible deterioration downhill. Finding enzymes that can regulate the dysfunctional Mitochondrion can keep the energy coming to our cells for long healthy life.