Ohio University researchers recently received $1.7 million to investigate aging and its connection to the growth hormone receptor.
The grant was part of a larger $8.6 million grant awarded to five institutions including the University of Michigan, the Mayo Clinic, The University of Texas, Southern Illinois University and OU by the National Institutes of Health.
The project began when researchers at OU discovered that removing the growth hormone receptor from mice increased their lifespan.
The oldest mouse we have had (that lacks the growth hormone receptor) is five years old. Normal mice live two to two and a half years. That is the longest-lived laboratory mouse in existence
said John Kopchick, the Goll Ohio Professor of Molecular Biology at the Edison Biotechnology Institute and professor of biomedical sciences in the OU College of Osteopathic Medicine.
Mice lacking the growth hormone receptor not only lived longer, but retained cognitive health for longer as well. These mice were significantly smaller than normal mice, about half the size, and obese.
Probably the most striking thing is that the mice were obese. Understanding how that fat can exist in a large amount and not provide problems can lead to some fundamental information about obesity in general said Darlene Berryman, an OU associate professor of human and consumer sciences and researcher on the project.
Although humans often have visceral fat, or fat that surrounds the organs, these obese mice had fat that was subcutaneous, or right underneath the skin.
Despite the fact that the mice lacking the growth hormone receptor were obese, they did not suffer from diabetes.
Researchers think this is because of the connection between growth hormone and insulin, said Edward List, a researcher at the Edison Biotechnology Institute.
Growth hormone blocks insulin's action. If you have too much growth hormone then you become insulin resistant which is partway towards diabetes. If you take away growth hormone you are more insulin sensitive
he said.
That improved insulin sensitivity, List said, is what they think leads to a longer health span.
The grant money will go towards removing the growth hormone receptor from certain tissues instead of the entire mouse.
Now we want to see if just taking that growth hormone receptor out of tissues that respond to insulin
so that would be the liver
muscle and fat
would lead to longer life. We know if you take it all away you live longer
now we want to see if there is a subset focusing on those insulin sensitive areas
Kopchick said.
This grant is especially significant due to its size, said David Wight, director of the Edison Biotechnology Institute.
It is always an accomplishment to get a grant. It's around 10 percent of the grants that get submitted actually get awarded. This is particularly significant in that it is a fairly large grant and part of a longer program project grant including a number of other institutions
he said.
Researchers hope the grant will help them to have a greater understanding of aging, Kopchick said.
We want a better understanding of the aging process. If we discover how to extend longevity then hopefully that will lead to understanding health span
healthy longevity
