The health benefits of having an older dad

Robin Wulffson MD's picture
aging, telomeres, genetic defects, IQ, psychiatric disorders
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A number of studies have reported that children of older fathers have an increased risk of disadvantages such as genetic disorders, psychiatric disorders, and lowered IQ. A new study, however, has noted a possible advantage: longer telomeres. For those who need enlightenment, a telomere is a region of repetitive DNA at the end of a chromosome, which protects it from deterioration. The telomeres have been likened to the aglets (tips) on the end of shoelaces that keep them from fraying. They are disposable buffers blocking the ends of the chromosomes; they are consumed during cell division and replenished by an enzyme, the telomerase reverse transcriptase. Dan T.A. Eisenberg of Northwestern University and colleagues presented their findings in the June 11 issue of the Proceedings of the National Academy of Sciences (PNAS).

The study group was comprised of 1,779 young Filipino adults and their mothers. The researchers measured the telomere length of DNA by assaying blood samples collected from the subjects; in addition, they determined the ages of the children’s fathers and grandfathers. Study results show that an individual’s telomeres became longer with their father’s age at birth; furthermore, their paternal grandfather’s age at their father’s birth also increases telomere length. Thus, the longevity effect is amplified over the generations. The researchers also suspect that longer telomeres may delay sexual development; as a result, additional energy is into additional resources necessary to maintain healthy functioning at more advanced ages. The researchers plan a future study that will evaluate health outcomes of children fathered by older dads.

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A study released last November by UCLA biologists holds future promise for promoting longevity in individuals regardless of parental age at birth. It was published first online and later in a print edition of the journal Cell Metabolism. The researchers reported that they had slowed the aging process in fruit flies (Drosophila melanogaster). They activated a gene called PGC-1, which increases the activity of mitochondria, the tiny power generators in cells that control cell growth and tell cells when to live and die. “We took this gene and boosted its activity in different cells and tissues of the fly and asked whether this impacts the aging process,” said David Walker, an assistant professor of integrative biology and physiology at UCLA and a senior author of the study. “We discovered that when we boost PGC-1 within the fly's digestive tract, the fly lives significantly longer. We also studied neurons, muscle and other tissue types and did not find life extension; this is telling us there is something important about the digestive tract.” He added, “By activating this one gene in this one tissue—the intestine—the fly lives longer; we slow aging of the intestine, and that has a positive effect on the whole animal,” said Dr. Walker, adding, “Our study shows that increasing PGC-1 gene activity in the intestine can slow aging, both at the cellular level and at the level of the whole animal.”

The biologists delayed the aging of the flies' intestines and extended their lives by as much as 50%. Dr. Walker noted that fruit flies have a life span of about two months. They start showing signs of aging after about one month, and they slow down, become less active and die. They are an excellent model for studying aging because scientists know every one of their genes and can switch individual genes on and off. “We all think about protecting the brain and the heart, but the intestine is a vital tissue type for healthy aging,” Dr. Walker said. “If anything goes wrong with the mitochondria in cells, the consequences could be devastating, and if anything goes wrong with our intestines, that may have devastating consequences for other tissue types and organs. Not only is the intestine essential for the uptake of nutrients that are a vital source of energy, but it is also an important barrier that protects us from toxins and pathogens in the environment. The intestine has to be well-maintained. He explained that the PGC-1 gene activates the cells' mitochondria and regulates mitochondrial activity in mammals and flies. The gene is a potential target for pharmaceuticals to combat age-related diseases.

Take home message:
This study does report an advantage of being the offspring of a holder father, it does not necessarily offset the risk of a genetic abnormality or other reported risks of having an older father at birth.

Reference: Proceedings of the National Academy of Sciences (PNAS)

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