More evidence supports previous research that exposure to current levels of Bisphenol A (BPA) can affect gene expression and fertility of women just 12 hours after exposure.
BPA is a chemical found in baby bottles, water bottles, canned foods and an array of other consumer products. The potential health effects of BPA are no longer debatable and the evidence of its impaired affect on fertility are now well established.
If you use water bottles or plastic of any kind (#3, #7, etc), conventionally packed products of any kind or cans and insulated cartons of any kind, chances are you have been exposed to BPA.
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.
Previous research from North Carolina State University and the National Institute of Environmental Health Sciences (NIEHS) showed significant reproductive health effects in rats that have been exposed to bisphenol-A (BPA) at levels equivalent to or below the dose that has been thought not to produce any adverse effects.
Now a new study published online in the journal Biology of Reproduction finds that exposure of pregnant female mice to the endocrine-disrupting chemical bisphenol A may produce adverse reproductive consequences on in fetal ovaries after the mother has first been exposed to the chemical.
The first 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.
The mice in this study were given BPA at doses thought to be equivalent to levels currently being experienced by humans.
Since it is known that all plastics migrate into food, it behooves us to look for the evidence at meaningful levels of detection, at and below single-digit parts-per-trillion (ppt) or ng/kg. Extremely low doses are especially relevant because they can upset the natural balance of the endocrine system. To paraphrase the report of an EPA workshop in 1996, endocrine disruptors (EDs) are external agents that interfere with the production, release, transport, metabolism, binding, action or elimination of natural hormones in the body responsible for maintaining internal balances and the regulation of developmental processes.
The research, conducted in the laboratory of Dr. Patricia A. Hunt at Washington State University (WSU) in Pullman, showed that BPA exposure affects the earliest stages of egg production in the ovaries of the developing mouse fetuses, thus suggesting that the next generation (the grandchildren of the females given BPA) may suffer genetic defects in such biological processes as mitosis and DNA replication.
In addition, the WSU research team noted that their study "revealed a striking down-regulation of mitotic/cell cycle genes, raising the possibility that BPA exposure immediately before meiotic entry might act to shorten the reproductive lifespan of the female" by reducing the total pool of fetal oocytes.
The list of negative health effects associated in some way with exposure to BPA is remarkably long. The most visible effect may be aneuploidy, a chromosome abnormality found in more than 5% of pregnancies. Most aneuploid fetuses die in utero. About one-third of all miscarriages are aneuploid, making it the leading known cause of pregnancy loss. Among conceptions that survive to term, aneuploidy is the leading genetic cause of developmental disabilities and mental retardation. About 1 in 300 liveborn infants and 1 in 3 miscarriages are aneuploid. It is associated with Down syndrome, Patau syndrome, Edwards syndrome, Klinefelter syndrome, Turner syndrome, Cri du chat syndrome, and Alzheimer's disease.
Each of these bears its own extensive list of maladies covering all parts and functions of the human body — both physical and mental. The condition at birth is directly related to the type of chromosome abnormality present in the embryo at the time of conception. It is well documented that aneuploidy contributes to the increased risk of spontaneous abortion when the female partner is older, but it is also thought that males more than 30 years old may increase the risk of spontaneous abortion when the female partner is less than 30 years of age.
Being one of many known endocrine disruptors, BPA affects development, intelligence, memory, learning, and behavior, skeleton, body size and shape, significant increase in prostate size, decreased epididymal weight and a longer anogenital distance, prostate cancer, reduced sperm count, both physical and mental aspects of sexuality. It may have something to do with obesity, and so many more that a separate article is required to list them all. In other words, if the fetus lives, any one or many parts of its body can be permanently affected. The problems may become evident at any age.
Future studies in Dr. Hunt's laboratory will focus on genetic changes produced over a range of BPA exposure.