An idea that has permeated gerontology for a century is that prolonged stress hastens the aging process. We're now at the exciting point where we have the knowledge and the tools to test that idea — and we're finding that it's true.
Using the groundbreaking work done by Nobel Prize-winning molecular biologist Elizabeth Blackburn as a foundation, Professor Mark Haussmann, biology, has discovered a link between stress and the aging process. He has done so by examining telomeres, the protective caps found at the ends of DNA strands. Likening telomeres to aglets — the plastic sheaths at the ends of shoelaces — Haussmann says, "Aglets can wear down, and eventually come off. When this happens, your shoelace unravels at the end. Telomeres are like aglets for our DNA. They wear down with age and high stress levels, and if they become too short our DNA becomes like the unraveling shoelace. This instability opens the door to cell death and disease, whereas long telomeres are linked to a long lifespan."
Haussmann's research examines how stressed mothers can pass "stress hormones," specifically the hormone corticosterone, to their children in the womb. Stress during pregnancy, he says, has been linked to offspring having difficulty dealing with stress later in life, as well as greater susceptibility to disease and even shorter lifespans.
“As the embryo's own physiological system for coping with stress is being set up, it's being bombarded with stress hormones from mom," he says. "That results in a system that has been set up to think that a high level of stress is normal. So later in life, when these individuals get into stressful situations, their stress systems overreact and release high levels of stress hormones. We're looking at how that has a cumulative effect on aging."
Haussmann and students in his lab are experimentally testing how exposure to prenatal stress hormones affects birds, specifically Japanese quail, throughout their three-year lifespan, a scientific first. "The first- and second-year students in my lab will be able to observe these birds the whole time they're at Bucknell," he says. "They're involved in the entire scientific process, from working with the animals to running the molecular assays to co-authoring the manuscripts.”
While Haussmann can't say with certainty whether the same mechanisms hold true for people as they do for birds, he said the "stress systems" of humans and Japanese quail are “amazingly similar, and so are their cellular aging mechanisms.”
Another study run by Haussmann and Bucknell students, published in the American Journal of Obstetrics and Gynecology, suggests a correlation between prenatal stress and a genetic predisposition toward shorter lives in humans. In that study, expecting mothers were surveyed about situations that caused stress during their pregnancy (such as job loss, the death of a family member or divorce) and were assigned a stress score based on their responses.
After the mothers gave birth, doctors at Drexel University in Philadelphia collected blood samples from the umbilical cords for analysis in Haussmann's lab. Haussmann and his partners found shorter telomeres, which correlate with shorter lifespans — in the children of mothers who experienced more stress during pregnancy.
“While we can’t say that those kids will have higher rates of disease or shorter lifespans, that's what current data in the field indicates,” he says.
Sometimes even Haussmann is surprised by how intimately our bodily systems are connected, but his evidence shows when you're always stressed you are, quite simply, prematurely aging. “An idea that has permeated gerontology for a century is that prolonged stress hastens the aging process,” he says. “We're now at the exciting point where we have the knowledge and the tools to test that idea — and we’re finding that it’s true.”
Updated Sept. 23, 2016
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