Wednesday / Apr 06 2016
Newspaper : The News
Some fantastic developments are taking place in health sciences. The growing understanding of the underlying chemistry of biological processes is leading to new approaches to the treatments of a multitude of diseases. One of the areas of intense research is to understand the causes of ageing and to slow down the ageing process – even to reverse it.
Human beings have sought to learn the secret to eternal youth and longevity since ancient times. The longer ages of mole rats may well have the answer. One of the reasons for ageing is the damage caused by oxidation reactions triggered by a reactive form of oxygen – oxygen radicals. They attack our DNA and important proteins and are among a number of causes of ageing. Certain ‘search and repair’ mechanisms exist in us that detect the damaged regions and remove or repair them. However as we grow older, these mechanisms become weaker, thereby resulting in wear and tear to our biological system, resulting in ageing.
One interesting fact is that mole rats live about 10 times longer (about 30 years longer) than mice and some other rodents. Prof Buffenstein and colleagues at the University of Texas Health Science Center in San Antonio have discovered that the level of oxidative damage caused to proteins in mole rats was much lower, and that the search and repair mechanisms in their biological systems were much more effective. If somehow we could achieve a similar increase in ages of human beings as found in mole rats, it would mean an average age of 700 years. The secret of longevity may lie in the cellular chemistry found within mole rats.
Both the amount and nature of the food that we consume each day is important in the context of the ageing process. It has been known for long that restricting the diet of worms, flies and mice results in a significant increase in their life spans.
This had not been demonstrated previously in mammals. Richard Weindruch and co-workers at the University of Wisconsin-Madison have shown that when monkeys are fed a low calorie diet (30 percent less calories than the control group) their life spans are increased significantly. In a related study carried out at the Mount Sinai School of Medicine in New York, Charles Mobbs and co-workers have established the linkage between reduction in food intake and living longer in humans.
Life spans are reduced due to ‘oxidative stress’ on living systems caused by the metabolism of glucose. If less calories are consumed, the reduction in glucose metabolism leads to the prolonging of lives in humans.
A high calorie diet, in contrast, accelerates the ageing process due to the greater oxidative stress and may even cause diabetes. If you eat too much cooked red meat, this too accelerates the ageing process. This is because it leads to the formation of certain chemicals (advanced glycation endproducts (AGE)) in the brain and other parts of the body, and these have been identified as a key factor of ageing and degeneration, particularly in Alzheimer’s disease (AD).
If ageing is a chemical process, then reversing the process and making people younger should also be possible. Amazingly this has now been achieved in animals. David Sinclair, professor of genetics at Harvard University, has found that a compound found in grapes and cocoa (resveratrol) actually reversed the ageing process in mice. “We’ve discovered genes that control how the body fights against ageing and these genes, if you turn them on just the right way, they can have very powerful effects, even reversing ageing – at least in mice so far”, said David Sinclair in an interview (http://www.abc.net.au/ news/2014-11-04/scientists-reverse-ageing-process-in-mice/5865714.)
The mitochondria are the energy engines in our body. The presence of the compound NAD (Nicotinamide Adenine Dinucleotide) is important for energy metabolism. The levels of this compound diminish with age and this has been identified as one of the important causes for mitochondrial deterioration and ageing. Its replenishment may also have a strong rejuvenating effect.
Regarding feeding of another closely related compound to mice, David Sinclair said “We fed them a molecule that’s called NMN and this reversed ageing completely within just a week of treatment in the muscle.”
Certain genes (called ‘sirtuins’) play an important role in the ageing process. Dr Leonard P Guarente, a biology professor at MIT had found in the 1990s that yeast cells lived longer if they were given less food, and even longer if a certain gene (SIR1) was present. SIR2 appeared to stop the aging process by preventing the production of waste materials in the cell.
We don’t have the gene SIR2, but we have another gene that SIRT1 that appears to perform similar functions. Both SIR2 and SIRT1 are responsible for repairing DNA within the body and suppressing certain other genes. This approach of identifying genes responsible for the ageing process may also lead to longer life spans.
The ‘clock of ageing’ in our bodies is believed to be located in a region of repetitive DNA at the end of the chromosome called a ‘telomere’. As we grow older the telomere gets shortened, as do the number of remaining years of our lives. It has been demonstrated that cells that do not experience the shortening of telomeres on cell division continue to divide indefinitely. Attempts are being made by scientists to protect the telomere from degradation in order to slow down or even reverse the ageing process. Researchers in Europe and the US have discovered a natural compound, codenamed TA-65, which has the remarkable property of activating the enzyme telomerase in the human body, thereby extending the length of the telomeres. This may lead to the extension of human life spans to 125 years or beyond.
For the present, however the secret to a longer healthier life is simple – eat less and make sure that your diet is composed largely of fruits and vegetables.
The writer is the former chairman of the HEC, and president of the Network of Academies of Science of OICCountries (NASIC).