Healthy aging in the average human body involves two basic factors. The first is related to the number of times our cells can reproduce before they die off and the second is the extent to which those dead or static cells are allowed to build up in tissues.
Every cell in the body carries the genetic information and chemical markers to inform it how to function, which genes must be switched on or off and when to divide to form another cell. The process of cell division involves the systematic winding of our DNA strands until they are lined up in X shapes with their corresponding pair, unless you’re a man, in which case the twenty-third pair comprises an X and a Y chromosome.
At the ends of each chromosome is a protective cap called a telomere. During cell division, the X shapes are split in half, before travelling along chemical threads to the far sides of the nucleus; a dense region of genetic information inside the cells. Those halves then recreate the missing part of their X shape, and the entire cell cleaves in two.
Every time this happens, the protective telomere caps get smaller, until the chromosome is no longer able to divide. They have reached a natural limit of how many times they can split. This is known as the Hayflick Limit, after Leonard Hayflick, Professor of Anatomy at the University of California in San Francisco, who discovered the phenomenon in 1961.
At this point, the cell either dies off releasing waste products that can cause inflammation, or simply lies in a static state. When all body systems are functioning properly, those dead or senescent cells are flushed from tissues and removed. There are times though, when the chemicals controlling the Hayflick Limit fail, and cells reproduced rapidly and randomly, leading to a higher risk of genetic mistakes. Those mistakes can form the basis of malignant growths and tumours, so it’s important that cells know when to stop dividing.
This continuous cell renewal occurs billions of times within our bodies during our lifetimes, ensuring efficient repair of our essential organs and tissues. Normal embryonic cells can…