Dad’s obesity could be inherited by multiple generations

Contact: Dr. Tod Fullston tod.fullston@adelaide.edu.au 61-883-138-188 University of Adelaide

The sperm of obese fathers could increase the risk of both their children and their grandchildren inheriting obesity, according to new research from  University of Adelaide.

In laboratory studies, researchers from the University’s Robinson Institute have found that molecular signals in the sperm of obese fathers can lead to obesity and diabetes-like symptoms in two generations of offspring, even though the offspring are eating healthily.

The results of the research are published online in The FASEB Journal.

“A father’s diet changes the molecular makeup of the sperm.  With obese fathers, the changes in their sperm – in their microRNA molecules – might program the embryo for obesity or metabolic disease later in life,” says the lead author of the paper, Dr Tod Fullston, who is an NHMRC Peter Doherty Fellow with the University’s Robinson Institute, based in Dr Michelle Lane’s Gamete and Embryo Biology Group.

“For female offspring, there is an increased risk of becoming overweight or obese.  What we’ve also found is that there is an increased chance of both male and female offspring developing metabolic disease similar to type 2 diabetes.

“This is the first report of both male and female offspring inheriting a metabolic disease due to their father’s obesity,” he says.

The study also extended into the second generation of progeny, which showed signs of similar metabolic disorders, including obesity, although it was not as severe as the first generation.

Dr Fullston says even if the obese father does not show any signs of diabetes, metabolic disease similar to diabetes was being seen in two generations of their descendants.

“It’s been known for some time that the health of a mother before, during and after pregnancy can impact on her child’s health, but the father’s health during this period is often overlooked,” Dr Fullston says.

“If our laboratory studies are translatable to humans, this could be a new and as yet unexplored intervention window into the epidemic of childhood obesity.

“A focus on the mother’s health is extremely important, but we’re seeing that the father’s health is also important for conception. It’s possible that by showing additional attention to diet and exercise in the father, this could have a positive impact on his future children and grandchildren.”

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Media Contact:

Dr Tod Fullston NHMRC Peter Doherty Fellow Robinson Institute The University of Adelaide Phone: +61 8 8313 8188 tod.fullston@adelaide.edu.au

Plastics chemical retards growth, function of adult reproductive cells

2009 re-post for filing

Contact: Diana Yates
diya@illinois.edu
217-333-5802
University of Illinois at Urbana-Champaign

IMAGE:Veterinary biosciences professor Jodi Flaws and her colleagues found that mouse follicle cells that were exposed to bisphenol A, a chemical found in many plastics, produced lower levels of steroid…

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CHAMPAIGN, Ill. — Bisphenol A, a chemical widely used in plastics and known to cause reproductive problems in the offspring of pregnant mice exposed to it, also has been found to retard the growth of follicles of adult mice and hinder their production of steroid hormones, researchers report.

Their study is the first to show that chronic exposure to low doses of BPA can impair the growth and function of adult reproductive cells. The researchers will describe their findings this month at the annual meeting of the Society for the Study of Reproduction.

A healthy, mature follicle, called an antral follicle, includes a single egg cell surrounded by layers of cells and fluid which support the egg and produce steroid hormones, said University of Illinois veterinary biosciences professor Jodi Flaws, who led the study with graduate student Jackye Peretz.

IMAGE:University of Illinois graduate student Jackye Peretz found that exposure to bisphenol A undermines the growth and function of adult reproductive cells.

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“These are the only follicles that are capable of ovulating and so if they don’t grow properly they’re not going to ovulate and there could be fertility issues,” Flaws said. “These follicles also make sex steroid hormones, and so if they don’t grow properly you’re not going to get proper amounts of these hormones.” Such hormones are essential for reproduction, she said, “but they’re also required for healthy bones, a healthy heart and a healthy mood.”

BPA is widely used in plastics and is a common component of food containers and baby bottles.

The chemical structure of BPA is similar to that of estradiol, a key steroid hormone, and it can bind to estrogen receptors on the surface of some cells. It is not known whether BPA blocks, or mimics or enhances estrogen’s activity on these cells, Flaws said.

Human studies have found BPA in many tissues and fluids, including urine, blood, breast milk, the amniotic fluid of pregnant women and the antral fluid of mature follicles. A national survey conducted by the federal Centers for Disease Control and Prevention in 2003-2004 found BPA in 93 percent of the 2,517 people (age 6 and up) who were tested.

BPA has a short half-life, Peretz said, and the chemical is quickly eliminated from the body. The fact that so many people tested positive “probably means that we’re being constantly exposed to BPA,” she said. The new study found that follicle growth was impaired after 48 hours of exposure to BPA, Peretz said. Reductions in three key steroid hormones – progesterone, testosterone and estradiol – were also seen after 120 hours of exposure to BPA.

The drop in steroid hormone production was quite dramatic. After 120 hours in a medium that included 10 micrograms per milliliter of BPA, mouse follicle cells produced about 85 percent less estradiol, 97 percent less progesterone and 95 percent less testosterone. Lower doses of BPA had a less dramatic – but still considerable – dampening effect on steroid hormone levels. And at 120 hours, follicle cells grown in the BPA medium were 25 percent smaller than normal, the researchers report.

A review of the health risks of BPA by the National Toxicology Program of the U.S. Department of Health and Human Services concluded in 2008 that while BPA has been shown to harm the reproductive health of laboratory animals in some studies, such adverse effects “are observed at levels of exposure that far exceed those encountered by humans.”

However, the NTP reported that laboratory studies that showed effects in animals exposed to low doses of BPA led it to have “some concern for effects on the brain, behavior and prostate gland in fetuses, infants and children at current human exposures to bisphenol A.”

The new study points to possible concerns in adults as well, Flaws said.

“I think there’s a need for more studies where people look in adult humans to see if BPA is affecting follicle growth and steroid hormone levels,” she said. If it is, that might help explain some infertility or menopausal symptoms, she said.

 

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Editor’s note: To reach Jodi Flaws, call 217-333-7933; e-mail jflaws@illinois.edu.