# Editor's Note: Elizabeth Helen Blackburn, an Australian-American Nobel laureate, currently the President of the Salk Institute for Biological Studies studied the telomere, a structure at the end of chromosomes that protects the chromosome. Blackburn co-discovered the telomerase, the enzyme that replenishes the telomere. For this work, she was awarded the 2009 Nobel Prize in Physiology or Medicine.

 

Telomeres reside as repetitive nucleotide sequences at each end of every chromosome. Their main function is to protect the end of chromosome from detoriation and from fusion with neighboring chromosomes. Telomeres have the role similar to the plastic tips on shoelaces, protects from fraying and sticking to each other, otherwise would destroy or scramble the organism’s genetic information. The telomere sequence in humans is TTAGGG; as a short DNA sequence with its repetition hundreds and even thousands of times over again and again. Humans have at young age, telomeres are about 8000-10000 nucleotides long which eventually get shortened with cell divisions, and when they reach a critical length, the cell stops dividing or dies. Thus, the processes of cell aging and cell death are regulated by telomeres as well in addition to other regulatory mechanisms.

What is the role of telomeres in ageing?

Shorter telomeres have a negative effect on several health aspects. Shorter telomeres have implications on genomic instability and oncogenesis. Short telomeres also increase the likelihood of cells as onset to senescence stage and the release of molecules associated to inflammation, another important risk factor for various diseases. Thus telomere shortening is the primary cause for age related breakdown of cells. The telomere length when reaches a critical limit, the cell undergoes senescence and/or apoptosis. Telomere length may therefore serve as a biological clock helps to determine the lifespan of an organism or a cell. Humans at old age are with shorter telomeres and have three and eight times increased risk to heart and infectious diseases, respectively.

Maintain the healthy secrets of your telomeres; How to lengthen the telomeres?

Telomere length, which can be affected by various lifestyle factors, can affect the pace of aging and onset of age-associated diseases. Rate of telomere shortening is therefore critical to an individual’s health and pace of aging which varies from individual to individual. Lifestyle factors may affect the health and lifespan of an individual by affecting telomere length.

- `Do not's': Smoking, exposure to pollution, lack of physical activity and lethargic lifestyle, obesity, stress, and an unhealthy diet increase oxidative burden and the rate of telomere shortening.

- `Do's': To preserve telomeres and reduce cancer risk and pace of aging, we may consider to eat less; include antioxidants, fiber, soy protein and healthy fats (derived from avocados, fish, and nuts) in our diet; and stay lean, active, healthy, and stress-free through regular exercise and meditation. Foods such as tuna, salmon, herring, mackerel, halibut, cat-fish, flax seeds, chia seeds, sesame seeds, kiwi, black raspberries, lingonberry, green tea, broccoli, sprouts, red grapes, tomatoes, olive fruit, and other vitamin C-rich and E-rich foods are a good source of antioxidants.

-`Lower your stress levels’ chronic stress can increase the telomeres to detoriate. A regular practice of twenty minutes a day mindful meditation helps to increase in the activity of telomerase, an enzyme which lengthens telomeres.

-`Physical Exercise’ the more different kinds of exercise the people did, the longer are their telomeres. Middle aged intense runners, had telomere lengths which were longer than their sedentary counterparts.

-`Spend time outside’ people with higher levels of vitamin D are more likely to have longer telomeres and vice versa. Thus individuals with higher levels of sunshine vitamin may actually age more slowly than persons with lower levels of this vitamin.

-`Sleep’ less than seven hours a sleep a night or going to bed different times a day, likely to suffer from oxidative stress and inflammation, that can shorten your telomeres.

-`Antioxidants’ the consumption of whole food plant-based diet and wide range of antioxidants neutralize free radical damage. These antioxidants can reduce free radical damage and preserve DNA function; antioxidants can even help repair DNA.

-`Eat foods high in folate’ plasma concentrations of folate even called vitamin B9 correspond to telomere length in both women and men because vitamin B9 has an essential role in the maintenance of DNA methylation and DNA integrity, both of which influence the length of telomeres.

 

Article by:

Dr. K Lakshmi Rao

Principal Scientist

Medical Biotechnology Complex, CCMB Annex II, Hyderabad

Email: lakshmi@ccmb.res.in