Study reveals birth defects likely caused by flame retardant
Research focuses on man's exposure prior to conception

Date:
June 9, 2020
Source:
University of Georgia
Summary:
A new study has shown that exposure to a now-banned flame retardant
can alter the genetic code in sperm, leading to major health
defects in children of exposed parents.



FULL STORY ==========================================================================
A new study from the University of Georgia has shown that exposure
to a now- banned flame retardant can alter the genetic code in sperm,
leading to major health defects in children of exposed parents.


========================================================================== Published recently in Scientific Reports, the study is the first to
investigate how polybrominated biphenyl-153 (PBB153), the primary
chemical component of the flame retardant FireMaster, impacts paternal reproduction.

In 1973, an estimated 6.5 million Michigan residents were exposed to
PBB153 when FireMaster was accidentally sent to state grain mills where
it made its way into the food supply. In the decades since, a range
of health problems including skin discoloration, headache, dizziness,
joint pain and even some cancers have been linked to the exposure.

More striking, the children of those who were exposed seemed to experience
a host of health issues as well, including reports of hernia or buildup
in the scrotum for newborn sons and a higher chance of stillbirth or miscarriage among adult daughters.

Yet, little work has been done to understand how the chemical exposure
could have impacted genes passed from an exposed father, said study
author Katherine Greeson.

"It is still a relatively new idea that a man's exposures prior to
conception can impact the health of his children," said Greeson, an environmental health science doctoral student in Charles Easley's lab
at UGA's College of Public Health and Regenerative Bioscience Center.



========================================================================== "Most studies where a toxic effect is observed in children look only to
the mothers and the same has been true of studies conducted on PBB153,"
she said.

Greeson and a team of researchers from UGA and Emory University used
a unique combination of observational and laboratory approaches to
demonstrate how PBB153 acted on sperm cells.

"Typically, scientific studies are either epidemiological in nature and inherently observational or focus on bench science, but in this study,
we did both," said Greeson.

This approach allowed the researchers to mimic the known blood exposure
levels of PBB153 in a lab environment.

"We were uniquely able to recreate this effect using our previously characterized human stem cell model for spermatogenesis," she said,
"which allowed us to study the mechanism that causes this effect
in humans." The team looked at the expression of different genes in
their human spermatogenesis model after dosing with PBB153 and found
marked alterations in gene expression between dosed and undosed cells, specifically at genes important to development, such as embryonic organ,
limb, muscle, and nervous system development.

"PBB153 causes changes to the DNA in sperm in a way that changes how
the genes are turned on and off," said Greeson. "PBB153 seems to turn
on these genes in sperm which should be turned off," said Greeson, which
may explain some of the endocrine-related health issues observed in the children of exposed parents.

Though the study used this model to directly replicate exposure to PBB153, Greeson says this approach could be used to better understand the impact
of other environmental exposures on reproduction, including large-scale accidental exposures to toxic chemicals or everyday exposures.

"Hopefully this work will lead to more studies combining epidemiology
and bench science in the future, which will tell us more about why we're
seeing an effect from an environmental exposure in human populations and encourage experimental studies to more closely mimic human exposures,"
she said.


========================================================================== Story Source: Materials provided by University_of_Georgia. Original
written by Lauren Baggett. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Katherine Watkins Greeson, Kristen L. Fowler, Paige M. Estave,
S. Kate
Thompson, Chelsea Wagner, R. Clayton Edenfield, Krista
M. Symosko, Alyse N. Steves, Elizabeth M. Marder, Metrecia
L. Terrell, Hillary Barton, Michael Koval, Michele Marcus, Charles
A. Easley. Detrimental effects of flame retardant, PBB153, exposure
on sperm and future generations.

Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-65593-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200609111052.htm

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