Marcelo Viegas – Life Length Scientific Director
According to growing scientific evidence, we can indeed do something to stop the shortening of our telomeres and age more slowly.
The age on our ID card is one of the single most important pieces of information in our society. We all know when our birthday is and how old we are. However, it is not our chronological age that results in our degree of aging, but rather our telomere length – our Biological Age – which can be compared to the “battery life” of our cells.
In early 1997, the birth of “Dolly” the sheep in the United Kingdom was announced. Dolly quickly became the most popular sheep in the world, as she wasn’t just any old sheep but in fact the first mammal to be cloned from the cell of an adult animal. This cloning was an experiment to demonstrate that even the oldest cells in our body retain all of the genetic information needed in order to reproduce a complete individual.
However, Dolly taught us much more than just genetics; she provided us with an insight into fully understanding the aging process. Our heroine developed arthritis and lung disease at a very early age and as a result she ended up dying at just six years old; half the average age of a sheep’s usual life expectancy.
It is thought-provoking to consider that Dolly’s “mother”, the sheep from which one of its cells had been cloned, was already six years old at the time of donating the cell. It is as if the sheep not only passed on to Dolly the DNA needed to become an identical sheep, but that she also passed on her age. It would appear that Dolly began her life with a biological age of six years old which is why she only lived for six more years!
This hypothesis was quickly confirmed. By inserting the nucleus of a cell from Dolly’s “mother” into an egg without a nucleus, it was possible to return to the very beginning of the genetic program so that the old cell would generate a complete sheep – Dolly. However, the telomere length remained the same as those of the mother sheep.
Telomeres? What are telomeres?
Telomeres are nothing less than one of the most important factors in determining our bodies’ true age. Explained in detail, we know that all living organisms are made up of cells that contain DNA (deoxyribonucleic acid), the molecules responsible for maintaining genetic information. All that we are is given to us either directly or indirectly through DNA. In higher organisms (of which humans are included), DNA is packaged inside the cell nucleus in linear structures known as “chromosomes”, that resemble a shoelace-like structure. Telomeres are the sequences at each end of our chromosomes. Following the above analogy, telomeres are like the plastic protectors at each end of our shoelace-like chromosomes.
We grow and develop because our cells grow and divide in order to generate new cells. Genetic information is so vital that cells must duplicate their chromosomes prior to dividing into daughter cells, thus preserving this genetic information from one generation to the next. The duplication of chromosomes is a highly accurate process that ensures the daughter cells receive faithful copies of the original genetic material.
However, there is an exception in the duplication of chromosomes; the two ends, the telomeres, get shorter after each cell division.
In scientific jargon, this phenomenon is known as the “end replication problem” and derives from the inherent nature of the replication mechanism of our chromosomes.
Telomeres protect chromosomes the same way as plastic covers protect laces. This is why telomeres are essential for cells to live. As cells divide, the telomeres get shorter and shorter until their length is critically short, at which point the cells die. You could say that telomeres act like biological clocks, that count down after each cell division imposing a limit on each cell’s life expectancy until the “clock” reaches “zero”. This feature of telomeres directly binds telomere length with an organism’s biological age, the “real” age of our body.
No doubt we have all noticed how some people seem to age faster than others, as if their chronological age does not quite correspond to their biological age. More and more evidence supports the idea that an unhealthy lifestyle can accelerate this shortening process. There are studies that have shown how obesity, being a smoker, and a sedentary lifestyle can shorten the length of our telomeres (therefore, increasing our biological age and thereby lowering our life expectancy).
Psychological stress also plays an important role in this respect. There is a study which has compared the telomere length in pre-menopausal women who have given birth to healthy children against women who have had children with some form of chronic illness. In this latter group, those who had endured some form of chronic stress for a greater number of years had shorter telomere length. Stress also has an impact on the children. According to a study carried out in Romania, children who spent their first years in orphanages had shorter telomeres than children who had been cared for by a host family.
The question that arises is, therefore, can we do anything to stop the shortening of our telomeres and age more slowly?
There is growing scientific evidence that suggests the answer is yes. Taking certain vitamins, antioxidants and minerals, has shown a positive correlation with telomere length. Exercise can reduce harmful fats and oxidative stress and help preserve our DNA and telomeres. In contrast to stress, rest and emotional balance also demonstrate a positive impact on our telomeres. There are also studies on mice (that have not yet been tested on humans) that show a diet with a restricted caloric intake prevents against the shortening of telomeres.
In Spain, we are fortunate to have the Life Length company – a world leader in the field of measuring telomere length.
Life Length measures both the average telomere length and the proportion of short telomeres, which represent the bottleneck for cell viability.
The company has announced the launch of a new version of their test that also includes a comprehensive distribution of telomere lengths. This innovation will no doubt help researchers to continue designing increasingly more solid studies to assess the impact that telomere length has on our life expectancy and quality of life.
BIBLIOGRAPHY
Shiels PG, Kind AJ, Campbell KH, et al (1999). “Analysis of telomere lengths in cloned sheep“. Nature 399 (6734): 316–7. Bibcode: 1999Natur.399..316H. doi:10.1038/20580. PMID 10360570
Canela A, Vera E, Klatt P, Blasco MA. (2007). Proc Natl Acad Sci U S A. 104(13):5300-5. PMID 17369361.