Expert: Walter Hintz - 4/14/2006

Question
What exactly causes people to age and eventually die? There was this one guy whom was talked about on 20/20 from Cambridge College who figures eventually science will allow people to live hundreds, even upwards to 1000 years of age. I think that is a little out there, and yet not. What causes aging exactly? What does it mean when the body breaks down? Can it not always bring itself back to perfect working order, and if not, why not? Does it have to do with the body collecting waste and not being able to remove it? Is there no way to help the body accomplish that if it is the case? Since mammals like dogs can live 1/7 our lifespan it doesn't seem much more than genetic that we're determined to "give up" at some point or another whether or not we're actually beyond repair. What do you know about the aging process and its causes, and do you think it could ever be stopped or slowed down, or maybe reversed periodically with futuristic treatments?

Answer
You have posed a lot of questions here James, most of which I have no answer for.  I developed and taught a college class called The Biology of Aging a few years ago. We studied all aspects of aging but the factors behind it are still mostly a mystery.  We know that the metabolic process generates oxidants, chemicals with high oxygen numbers like hydrogen peroxide, a byproduct of cellular metabolism. Oxidants are also generated when white blood cells destroy bacteria.  Oxidants damage cellular DNA.
The life span has been increasing not because we are conquering aging but because we are delaying the pathology that accompanies aging.  We are combating the parasites.
It appears that our cells have a built in mortality when in tissues and organs.  If we culture cells outside of the body they are immortal. In the early 1900's a guy named Alex Carrel grew chick heart cells in a culture for 27 years.  They only died when he stopped culturing them.
To summerize: Immortality at this point is not an option. The cause of death of an individual is organ failure either from invasive organisms or because the process of cell division fails: why it fails we do not know.