Detection of PCBs and their metabolites (OH-PCBs) in the fetal brain of a Japanese macaque

September 14, 2020

Hydroxylated polychlorinated biphenyls (OH-PCBs) are metabolites of PCBs and known endocrine disruptors in humans. Of particular concern regarding this kind of effect has been the disruption of the thyroid hormone homeostasis by OH-PCBs. Some OH-PCB congeners are involved in disrupting TH transport by competitive binding to the thyroid hormone transport protein, transthyretin (TTR) in mammalian blood. Prenatal OH-PCBs exposure may disrupt fetal brain development during the critical period of thyroid hormone action. Congenital hypothyroidism causes cretinism and mental retardation, and an insufficient thyroid hormone signaling has been suggested as one of the causes of attention deficit/hyper activity disorder (ADHD). However, there have been limited studies on the OH-PCBs transfer to the fetal brain, particularly in primates.

In this study, we selected the Japanese macaque (Macaca fuscata) as a model animal for the fetal transfer of OH-PCBs in humans, and revealed OH-PCB concentrations and their relationships in maternal and fetal blood, liver, and brain. L-thyroxine (T4)-like OH-PCBs, including 4OH-CB187 as a major congener in humans, were found in high proportions in the blood, liver, brain, and placenta of pregnant Japanese macaques. OH-PCBs were detected in the fetal brain (7.2 ~ 32 pg/g wet wt.), indicating their transfer to the brain in early pregnancy. 4OH-CB187 and 4OH-CB202 of OH-PCB congeners were the major congeners found in the fetal brain, indicating that these T4-like OH-PCBs are transported from maternal blood to the fetal brain via the placenta. These results are important as a potential model for further assessing and understanding of the ability of OH-PCBs to alter neurodevelopment in the human fetus.

In this study, OH-PCBs concentrations in the fetal brains of the Japanese macaques were comparable to the levels that suppressed the T3-induced transcriptional activation of the thyroid hormone receptor and caused neurodevelopmental abnormalities in cerebellar Purkinje cells of mice in a previous study. The brain of the human fetus may be exposed to higher PCB contamination levels than the Japanese macaque fetus; OH-PCB concentrations may thus exceed the levels that induce adverse effects on neurodevelopment. Considering the chronic exposure to PCBs in humans, further studies on the effects of their long-term exposure on fetal brain function are needed.
-end-


Ehime University

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.