London, Aug 11 : In a breakthrough study, scientists at the Albert Einstein College of Medicine of Yeshiva University have successfully prevented functional declines in the livers of old mice.
Lead researcher Dr. Ana Maria Cuervo, associate professor in the departments of developmental and molecular biology, medicine and anatomy and structural biology at Einstein, said that the livers of older animals functioned as well in getting rid of damaged protein as they did when the animals were much younger.
For the study, Cuervo created a transgenic mouse model having an extra gene that codes for the receptor that normally declines in number with increasing age.
Through another genetic manipulation, she turned this extra gene only in the liver, and at a time of her choosing, merely by changing the animals' diet.
After turning on the added receptor gene in six month old mice, they were then examined at 22 to 26 months of age (equivalent to approximately 80 years old in humans).
It was found that the liver cells of transgenic mice digested and recycled protein much more efficiently than in their normal counterparts, and just as efficiently as in normal six-month old mice.
Cuervo then injected a muscle relaxant into very old transgenic mice and very old normal mice.
The very old transgenic mice metabolised the muscle relaxant much more quickly than very old normal mice and at a rate comparable to young normal mice.
"Our study showed that functions can be maintained in older animals so long as damaged proteins continue to be efficiently removed - strongly supporting the idea that protein buildup in cells plays an important role in aging itself. Even more important, these results show that it's possible to correct this protein 'logjam' that occurs in our cells as we get older, thereby perhaps helping us to enjoy healthier lives well into old age," Nature magazine quoted Cuervo as saying.
Her team is now planning to study animal models of Alzheimer's, Parkinson's and other neurodegenerative brain diseases to see whether maintaining efficient protein clearance in the brain might help in treating them.
She will also investigate whether maintaining efficient protein clearance in all the body's tissues will influence longevity, and prevent the functional losses associated with growing old.
The study is published in the online edition of Nature Medicine.