You probably know someone who seems to age slowly, appearing years younger than their date of birth suggests. And you’ve probably seen the opposite – someone whose body and mind seem to be much more ravaged by time than others. Why do some people seem to glide through their golden years while others struggle physiologically in midlife?
I have worked in the field of aging throughout my scientific career, and I teach cellular and molecular biology of aging at the University of Michigan. Aging research is not the same as finding the one cure that will solve everything you may experience as you age. Instead, the work of the past decade or so shows aging to be a multifactorial process – and no single intervention can stop it.
What is getting old?
There are many different definitions of aging, but scientists generally agree on a few common features: Aging is a time-dependent process that results in increased vulnerability to disease, injury, and death. This process is both intrinsic, when your body encounters new problems, and extrinsic, when environmental insults damage your tissues.
Your body is made up of trillions of cells, and each one is not only responsible for one or more functions specific to the tissue it lives in, but it has to do all the work to keep itself alive. This includes metabolizing nutrients, getting rid of waste, exchanging signals with other cells and adapting to stress.
The trouble is that every single process and component in every one of your cells will be disrupted or damaged. So your cells spend a lot of energy every day preventing, recognizing and solving these problems.
Aging can be thought of as the gradual loss of the ability to maintain homeostasis – a state of balance among body systems – by not being able to prevent or recognize damage and malfunction, or by failing to adequately or adequately resolve problems. fast as they happen. Aging results from a combination of these issues. Decades of research have shown that almost all cellular processes become weaker with age.
repair DNA and recycle proteins
Most research into cellular aging focuses on studying how DNA and proteins change with age. Scientists are also addressing the possible roles of many other important biomolecules in the cell in aging.
One of the main jobs of the cell is to maintain its DNA – the instruction manual that the cell’s machinery reads to produce specific proteins. DNA maintenance involves protecting genetic material and the molecules attached to it from damage, and accurately repairing it.
Proteins are the workers of the cell. They carry out chemical reactions, provide structural support, send and receive messages, store and release energy, and much more. If the protein is damaged, the cell uses mechanisms involving special proteins that try to fix the broken protein or send it out for recycling. Similar mechanisms push proteins out of the way or destroy them when they are no longer needed. That way, its components can later be used to build a new protein.
Aging affects a delicate biological network
The cross-talk between the components inside cells, cells as a whole, organs and the environment is a complex and ever-changing network of information.
When all processes involved in the creation and maintenance of DNA and protein function are working normally, the various compartments within a cell that serve specialized roles – called organelles – can maintain the health and function of the cell. For an organ to function well, most of the cells that make it up must function well. And for a whole organism to survive and thrive, all the organs in its body must work well.
Aging can lead to dysfunction at any of these levels, from the subcellular to the organism. A gene that encodes an important protein for DNA repair may have been damaged, and now all the other genes in the cell are more likely to be repaired incorrectly. Or the cell’s recycling systems may no longer be able to degrade dysfunctional components. Even the communication systems between cells, tissues and organs can be compromised, making the organism unable to respond to changes within the body.
Random chance can lead to an increasing burden of molecular and cellular damage that gradually goes unrepaired over time. As this damage accumulates, damage is also being accrued to the systems that are supposed to repair it. This results in a cycle of increased wear and tear as cells age.
Anti-aging interventions
The interdependence of life’s cellular processes is a double-edged sword: Sufficiently damage one process, and all other processes that interact with or depend on it are impaired. However, this interconnection also means that the addition of one highly interconnected process could also improve related functions. In fact, this is how the most successful anti-aging interventions work.
There is no silver bullet to stop aging, but certain interventions seem to slow aging in the laboratory. Although there are ongoing clinical trials investigating different approaches in humans, most of the current data comes from animals such as nematodes, flies, mice and non-human primates.
One of the best-studied interventions is caloric restriction, which involves reducing the amount of calories an animal normally eats without depriving it of essential nutrients. An FDA-approved drug used in organ transplants and some cancer treatments called rapamycin appears to work by using at least a subset of the same pathways that calorie restriction activates in the cell. Both affect the signaling hubs that direct the cell to conserve its existing biomolecules rather than grow and build new ones. Over time, this cellular version of “reduce, reuse, recycle” removes damaged components and leaves behind a higher percentage of functional components.
Other interventions include changing the levels of certain metabolites, selectively destroying senescent cells that have stopped dividing, changing the gut microbiome and behavioral modifications.
What all these interventions have in common is that they affect core processes critical for cellular homeostasis, become dysregulated or dysfunctional with age and are linked to other cellular maintenance systems. Often, these processes are the central drivers for mechanisms that protect DNA and proteins in the body.
There is no single reason to get old. No two people age in the same way, and indeed, no two cells do. There are many ways to lose your basic biology over time, and these add up to creating a unique network of aging-related factors for each person that makes finding an anti-aging treatment very challenging. which suits all.
However, research into interventions that target multiple important cellular processes at the same time may help improve and maintain health for a greater portion of life. This advance could help people live longer in the process.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Ellen Quarles, University of Michigan
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Ellen Quarles does not work for, consult with, own shares in or receive funding from any company or organization that would benefit from this article, and does not she has disclosed any relevant connections beyond her academic appointment.