How long can human beings live? Is there an outside limit? Do we know enough about aging to break through possible biological barriers? Is the current approach to curing “age associated diseases” like Alzheimer’s flawed? Experts are sharply divided.
In 1962 eminent biologist Leonard Hayflick discovered that normal human fetal cells replicate a limited number of times. This phenomenon promptly acquired the moniker the “Hayflick Limit.” Later, biologists Calvin Harley and Carol Greider provided the molecular explanation for the Hayflick limit with their discovery that telomeres, the DNA biological material in every cell of our bodies, diminish each time cells divide.
In contrast, cancer cells, which are immortal, produce an enzyme called telomerase that maintains the length of telomeres and enables cancer cells to replicate without limit. The strategy of extending the life of normal cells by injecting telomerase has proven thorny, as reported by Dr. Elizabeth Blackburn, co-discoverer of telomerase: “too much telomerase can help confer immortality onto cancer cells and actually increase the likelihood of cancer, whereas too little telomerase can also increase cancer by depleting the healthy regenerative potential of the body..telomerase shots are not the magical anti-aging potion….”