I learned this today. We all age and there are nine problems that aging causes in humans. These are DNA mutations, faulty gene expressions, shortening telomeres, the build up of faulty proteins, worn out cells don’t die, mitochondria become faulty, metabolism becomes faulty, stem cells become exhausted, and cells lose the ability to communicate with each other.
DNA mutations happen because our DNA is replicated constantly. Every time a cell divides to make new cells, the DNA is replicated. Because so many replications happen every second, it is inevitable that there will be errors. However, our cells are very good at weeding out these errors. During the replication process, the DNA is proofread and if anything is out of order, it is fixed. Then again, after it has replicated, it is checked for any errors and fixed here too. This system is almost perfect, but almost perfect means that some errors do get through and as we get older, these errors start to build up. These errors can then be replicated, which can cause cells to break down or cause cancer.
Faulty gene expressions are caused because the proteins that control which genes get expressed in cells become less accurate. All our cells have the same DNA, but they have different genes, which is why a liver cell and a brain cell are different. This is decided by proteins and is called epigenetic moderation. As we get older, the proteins become less accurate and start to trigger the wrong genes, or not trigger the right genes. If a gene is silenced in a cell that fights tumors, it can lead to cancer.
Shortened telomeres are caused by age. Telomeres are protective caps on the tops of each strand of DNA. Every time cells divide and the DNA is replicated, the telomeres get a little bit shorter and looser. The job of the telomeres is to hold the DNA strands together and to protect them from damage. When the telomeres unravel, it leaves the DNA open to damage.
Faulty proteins build up because our bodies lose the ability to eliminate them. Proteins do almost all of the work within cells in our bodies. They wear out quickly so they are constantly being produced. Sometimes faulty proteins are produced and they are very quickly discarded by the cells. As we get older, our cells lose the ability to remove these faulty proteins and they start to build up. These proteins can become toxic and cause damage. Alzheimer’s disease is caused by a buildup of toxic proteins.
Worn out cells don’t die and spread inflammation throughout the body. These are called senescent cells. Usually, when a cell is old and no longer efficient, it dies and is cleaned out of the body by white blood cells. This leaves room for new cells. As we age, the worn-out cells become resistant to death and hang around, causing inflammation in the surrounding tissue and damage.
Mitochondria become faulty because they become inefficient and dysfunctional. Mitochondria are the part of the cell that produce energy by converting oxygen and sugars into energy. When they age, they break, and they can start to produce a form of oxygen that can damage DNA and proteins.
The metabolism becomes faulty because the body starts taking up fewer nutrients. The cells of older people have more fat in them than younger people because their cells don’t digest it properly. This leads to the body overestimating how much glucose and fat is in the body, leading it to cut down on the amount of nutrients it takes in. This can be effective in the short term because it allows overworked cells to fix themselves, but in the long term it can be disastrous. It can also lead to the body cutting down on how much insulin it produces, causing age-related diabetes.
Stem cells become exhausted as they get older. The stem cells in our bodies are the cells that can become any other type of cell. As they age, they basically get tired and stop replicating as quickly. This severely limits the body’s ability to fix itself and means that a lot of tissue that should be renewed isn’t renewed.
Cells lose the ability to communicate with each other which can affect the immune system. Our cells constantly communicate with each other through the blood stream. As they age, some cells lose this ability. This can turn them into senescent cells and it can also prevent the immune system from knowing what to clean and out and where it is.
All of these nine things happen in our bodies as we age. They usually happen to the point where our bodies succumb to one disease or another and we die. Currently, research is being done into several of these areas because drugs and supplements that are currently on the market have been shown to improve one or more of the problems. The trouble is, surprisingly, there isn’t a lot of research money there yet. Big Pharma don’t want to put money into research when the drug is one that is already available. Still, it looks like at some point in the near future some big developments in the area of aging will appear. And this is what I learned today.
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Photo by juan mendez: https://www.pexels.com/photo/portrait-photo-of-elderly-man-in-blue-collared-shirt-and-black-hat-3075517/
Sources:
BBC Science Focus Magazine, January 2022
https://www.nature.com/scitable/topicpage/cells-can-replicate-their-dna-precisely-6524830/
https://www.nature.com/scitable/topicpage/dna-replication-and-causes-of-mutation-409/
https://en.wikipedia.org/wiki/Telomere
https://www.sciencefocus.com/the-human-body/what-happens-to-cells-in-our-bodies-when-they-die/
https://www.solongevity.com/en/news-en/why-dowe-age-identify-9-biological-causes/
https://www.frontiersin.org/articles/10.3389/fendo.2018.00258/full