Why do we get older?

As functioning human beings, we are continually forming new cells to replace other cells that die off. Stem cells throughout our body are constantly differentiated for cell replacement and tissue regeneration. However, as we age, more and more of our stem cells lose the ability to multiply and form new cells. This eventually leads to the failure to adequately replace lost cells, regenerate tissue, and maintain homeostasis in our bodies.

Interestingly enough, the polyp Hydra does not show any signs of aging that is characteristic in humans, and they appear potentially immortal. It has been discovered that the stem cells in the Hydra are active during all its life, and this phenomenon has been traced back to a gene known as the FoxO gene. It turns out that this gene is present in our bodies as well, and it is now known that there is a direct link between this FoxO gene and aging.

This area of research is interesting because aging is something that everyone experiences, yet the physiology behind it is still not completely understood. With an increased understanding of aging and the genes, biochemical pathways, and mechanisms which control it we may someday be able to increase the quality of life and suppress the negative effects that are associated with aging.

Here is the article:
http://www.sciencedaily.com/releases/2012/11/121113091953.htm