liver article LEF

[Guest guest]

Not pushing LEF here: Interesting because I thought I had read somehwere the liver is the only organ that grows.

http://www.lef.org/featured-articles/spindler_press_release03.html

"L.E.: Your paper was based on the liver. What is the importance of the liver in human aging?

S.S.: The liver is an interesting organ. It is one that ages well. There are people who, of course, die from liver disease. That is a killer of the elderly. We were attracted to studies on the liver because it has such a powerful influence on physiology. One major problem that develops with aging is metabolism of drugs. They're not metabolized as well, partially because of loss of the enzymes that are involved in metabolism and partially because of a decrease in blood flow to the liver and in the volume of the liver with age. Most of the proteins that are circulating through your body in the blood, that aren't in blood cells, come from the liver, and the composition of those proteins has a major impact on wound healing, on clotting and on atherosclerosis. The composition of your blood as far as glucose and insulin levels go is partially due to the responsiveness of the liver to insulin, and has a major impact on vision and on your circulatory system. So the liver sits at a very central spot. Also, it's partially mitotic. So far, gerontologists have been attracted very often to organs whose cells don't divide very much. There is a good rationale for that interest, because these organs can't create new cells when old cells get damaged or die. But most of the tissues in our body are able to renew themselves, and many of those tissues that can renew themselves have major problems with age. They have problems with being able to renew themselves properly. So I think that they also are very important to look at.

L.E.: Did the changes you observed actually reflect changes in liver function that normally occur with aging?

S.S.: We found quite a number of changes that correlate well with the known changes in liver function. We and others have shown that there is a decline in the expression of enzymes that are involved in drug metabolism in the liver, and that fits very well with the loss of those differentiated (liver-specific) functions. Other specialized (differentiated) functions of tissues begin to decline with age, and certainly there was a decline in genes that are important for cell division and an increase in genes that tend to block cell division. That, for instance, fits in very well with the loss of the capacity of the liver with age to repair itself and to produce new cells that replace damaged cells."

Regards.