Telomeres are believed to regulate the aging of a cell, which is known as cellular senescence. Not much is known about telomeres, but here is what we do know.
The telomere is the tip of a chromosome. A chromosome is an individual molecule of DNA (when a cell is getting ready to divide). Think of a chromosome as a shoelace. The tips of the shoelace are telomeres.
Telomeres play a role in cell division. All cells divide, except heart, brain, and most muscle cells. Cells in the skin divide constantly. A cell divides about 50 times before it dies. This is known as the Hayflick limit.
Each time the cell divides, the telomeres get shorter. Eventually, the whole telomere disappears, at which point the cell can no longer divide. It becomes senescent and then dies.
A senescent cell is a cell that can no longer divide. It is irreversibly damaged and non-functional. It is on its way to death. In this “pre-death” period, the cell is completely non-productive.
Cancer cells, which never die, have very long telomeres, which is why they can keep on replicating. In contrast, normal cells have shrinking telomeres.
The presence of telomeres on the ends of chromosomes are believed to protect the DNA. Researchers are trying to find ways to extend the life of these telomeres (i.e. prevent them from getting shorter). But as of today, there are no ingredients that can actually accomplish this.
Wear and Tear
The Wear & Tear Theory of Aging dates back to the early 1800’s. Normal or excessive wear and tear on the body eventually causes us to die of disease.
The body can fix wear and tear up to a point. But with age, we lose our ability to repair abuse caused by chemical or physical agents.
What happens to a car if you drive it recklessly on harsh road conditions and don’t do any maintenance on it? It wears out. Eventually, it breaks down.
Same thing happens to cells. Cells deteriorate from normal wear and tear too.
Hormones (Neuroendocrine System)
With age, our hormone production declines. Hormones regulate many functions in the body.
Hormones are controlled by the endocrine system and the brain. Hence, this mechanism of aging is the called the Neuroendocrine Theory of Aging.
The neuroendocrine system is a tightly coordinated system. When just one hormone is off balance, it can affect many other body functions.
Aging causes us to produce less of the important hormones, which can lead to a decline in cell function and less repair.
This theory is similar to the Wear and Tear Theory.