What Is The Hayflick Limit?
Related News: Stem Cell DefinitionsWhen discussing stem cell research, especially when looking at potential relationships to cancer, one often comes to articles pertaining to the "Hayflick Limit". The Hayflick Limit is also quite important when one is discussion regenerative medicine. So any discussion of cellular death, regeneration, cancer, or stem cells as a whole, one cannot overlook the importance of this theory.
Back in the 1960's, Dr. Leonard Hayflick found in his research at the Wistar Institute in Philadelphia that lung tissue appeared to die out after the cells had divided a certain number of times .. essentially 50 times.
To take this further, he took cell cultures that had been frozen after dividing 25 times. Once the cells were thawed, they would continue until the 50 division limit was reached, then still die. This is now known as the "Hayflick Limit".
Furthermore, as the cells neared the end of their division limit, the cells would begin to resemble older tissue. This appearance included age related pigments which is found in aged hearts and brain cells.
Research revolving around the Hayflick Limit led to speculation regarding a "cellular clock". Essentially it has been thought that cellular clocks are regulated for each individual cell or controlled systemically by the hypothalamus of the brain.
Another theory is that control is exerted by the DNA, since as we know DNA is the essential blueprint for all our genes.
Posted on July 27, 2005 03:43 PM