- During aging, more and more senescent cells arise in our tissues.
- Senescent cells are cells that have become damaged, but that resist dying. They keep staying alive, and secrete substances that damage surrounding, still healthy cells.
- Senescent cells undermine the proper functioning of tissues, especially when they accumulate above a certain threshold, secreting substances that are proinflammatory, damage the tissues, and accelerate aging.
- Specific substances can destroy senescent cells. Such substances are called “senolytics”. Examples of natural senolytics are fisetin and quercetin.
Zombie Cells and their Role in Aging
Senescent cells arise from normal cells. When normal cells get too damaged (they accumulate too much DNA damage for example), they could devolve into cancer cells. To prevent this, breaks are put on these damaged cells: they cannot divide anymore, so that they cannot become cancer cells. They became senescent cells.
These senescent cells can no longer divide, but they do secrete all kinds of substances that damage the surrounding healthy cells. Such substances are pro-inflammatory compounds (cytokines), matrix metalloproteinases that break down tissue, IGF, and so on
The Aging Process
When we get older, senescent cells accumulate in the skin, contributing to sagging of the skin and wrinkles. Senescent cells accumulate in the joints, damaging the cartilage, contributing to osteoarthritis. Senescent cells in the blood vessel walls lead to stiffer blood vessels which are more prone to breaking and clogging up.
Senescent cells secrete proinflammatory substances that circulate in the body, damaging stem cells, and hindering their functioning. A proinflammatory environment can also stimulate the growth of cancer cells.
Normally, the immune system clears up senescent cells, but during aging the immune system starts to decline so more and more senescent cells arise in the body. Studies show that clearing away senescent cells can ameliorate various aging-diseases and symptoms at the same time.