For a long time, aging was treated as the natural “wear and tear” of the body, an unavoidable consequence of time passing. Modern biology, however, shows something different: aging is a complex, multilevel biological process that can be described through specific mechanisms.
In 2013, a model known as the hallmarks of aging was proposed in the journal “Cell,” organizing these processes into a coherent framework. Today, it includes 12 mechanisms that together influence the pace of aging and lifespan.
Aging from a biological perspective. What really happens in the body?
At first glance, aging may seem like a simple consequence of time passing. From a biological perspective, however, it is a much more complex process. Our cells constantly maintain balance by repairing DNA, removing damaged proteins, regulating gene activity, and adjusting energy production to the cell’s needs.
These mechanisms allow the body to function despite everyday stressors. With age, however, their effectiveness begins to decline. Small amounts of damage accumulate inside cells, while repair systems become less precise. Gene regulation changes, mitochondrial efficiency decreases, and communication between cells becomes less effective.
In recent decades, advances in molecular biology have revealed an increasing number of processes taking place in aging cells, from DNA damage to metabolic dysfunction. To organize this knowledge, scientists proposed a model describing the biological mechanisms that drive aging.
From telomeres to the complex biology of aging
One of the first clues to attract researchers’ attention was telomeres, structures that protect the ends of chromosomes. For some time, their shortening was believed to be the main mechanism of aging.
In an interview with Elevate, Dr. Dorota Komar explained how our understanding of aging has changed with each new discovery:
“Telomeres become shorter with each cell division, but we also know of cells with very short telomeres that show no signs of aging. Several years ago, when we began studying the mechanisms of aging, it seemed that we had identified its main cause, telomere shortening. Over time, however, we began discovering more and more processes that also play a role.”
Initially, nine mechanisms were identified. Today, the model includes twelve.
“When it comes to aging, DNA methylation is one of the areas we only began studying intensively relatively recently, and it is developing very rapidly. As a scientist, I cannot say that it is the most important aspect of aging. However, we are learning more and more about this process, and it appears to be one of the key mechanisms,” Dr. Komar added.
The 12 mechanisms of aging, a map of the processes that shorten life
The most important biological mechanisms associated with aging include:
Molecular damage
The aging process begins with changes in the biological information stored within the cell.
Mechanisms:
telomere shortening,
genomic instability, meaning DNA damage,
epigenetic changes, including the DNA methylation changes mentioned above,
loss of proteostasis, meaning reduced protein quality control.
Disruptions in metabolism and energy production
Over time, adaptive mechanisms begin to function less effectively.
Mechanisms:
deregulated nutrient sensing, meaning disruptions in how the body manages energy,
mitochondrial dysfunction,
impaired macroautophagy, meaning a reduced ability of cells to recycle damaged components,
cellular senescence.
Loss of regenerative capacity and chronic inflammation
Cellular changes begin to affect the functioning of entire tissues.
Mechanisms:
stem cell exhaustion,
altered intercellular communication,
chronic inflammation, known as inflammaging,
microbiome dysbiosis.
All these processes are closely connected. Disruption in one mechanism often triggers further changes in cells and tissues.
Why does aging increase the risk of disease?
What does this mean for our health? Over time, the risk of chronic diseases increases because they arise from many of the same biological processes that drive aging. In other words, we do not age because we become ill. We become ill because we are aging biologically.
The connection between aging and disease is easiest to see through specific examples:
- Genomic instability increases the risk of cancer.
- Metabolic dysfunction contributes to the development of type 2 diabetes and other metabolic diseases.
- Mitochondrial dysfunction and loss of proteostasis disrupt nerve cell function and are associated with neurodegenerative diseases.
- Chronic inflammation increases the risk of cardiovascular disease.
According to an Elevate Speaker
How is epigenetics changing the modern approach to aging?
“Disease is, in a sense, a category we have defined ourselves, a description of a situation in which the body functions differently from what we consider optimal. From a biological perspective, changes in gene function must occur before symptoms of disease appear. Even earlier than changes in gene expression, epigenetic changes take place.rnrnThis is why analyzing the epigenome may allow us to detect processes leading to disease before clinical symptoms appear. Medicine already uses concepts such as prediabetes, a condition in which blood glucose remains below the diagnostic threshold for diabetes but indicates that harmful changes are beginning to develop in the body.rnrnIn the future, diagnostics may rely to a large extent on the analysis of epigenetic profiles. By comparing them with known patterns of epigenetic change, it may become possible to determine which disease processes a given profile indicates. We already have algorithms that calculate epigenetic age, and in the future, different epigenetic indicators for specific diseases may also be developed.”rn
Can we influence the mechanisms of aging, and how?
Although aging cannot be stopped completely, a growing body of research shows that the pace of some biological processes can be influenced through lifestyle and emerging therapies.
The strongest scientific evidence concerns everyday factors that affect cellular function and metabolism. The most frequently mentioned include regular physical activity, adequate sleep, a balanced diet, and reducing chronic stress.
At the same time, research is advancing on interventions that target the mechanisms of aging. Scientists are studying senolytics, compounds that remove old and dysfunctional cells, as well as epigenetic cellular reprogramming. Their effectiveness can be assessed using various methods for measuring biological age.
One of the most promising areas of research is the possibility of influencing epigenetic processes. As Dr. Dorota Komar notes:
“It is not always necessary to reverse every epigenetic change. In laboratory models, reversing a single change can trigger an entire cascade of processes leading to broader cellular reprogramming. We also know that the mechanisms of aging are interconnected. When we successfully influence one of them, it often leads to changes in several others.”
You can read more about epigenetics in our article Do You Know How Old You Really Are? What You Should Know About Biological Age.
Conclusions
The more we learn about the biology of aging, the clearer it becomes that aging is not a single process, but an entire network of interconnected mechanisms. Understanding this network may one day transform the way we think about health, disease, and lifespan.
