Polychlorinated and hydroxypolychlorinated biphenyls. Influence on child neurological and endocrine development

PhD-ceremony: Ms. S.D. Soechitram, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Polychlorinated and hydroxypolychlorinated biphenyls. Influence on child neurological and endocrine development

Promotor(s): prof. P.J.J. Sauer

Faculty: Medical Sciences

PCBs and dioxins are persistent to environmental (chemical or biological) degradation and accumulate in the food chain because of their lipophylic nature and stability. Developmental effects on neurobehavioral, reproductive and endocrine parameters were observed in experiments in animals, in background and accidentally exposed human infants after in utero and lactational exposure to PCBs and dioxins. More recently, concerns raised about the degradation products of PCBs, the hydroxylated PCBs. In this Renco study we measured the levels and effects of PCBs and OH-PCBs on neurological and endocrine development in newborns till the age of 18 months. OH-PCBs cross the placenta more easily than PCBs because of their water solubility and binding to TTR. PCBs however influence T3/rT3 ratio negatively which resemble inhibition of type III deiodinase activity (D3). D3 is predominantly found in placenta en fetal brain. This might suggest that PCBs and OH-PCBs can also have a negative effect on neurological outcome (negative effects on motor optimality scores were measured). Brain development depends on appropriate levels of thyroid hormones during critical developmental periods. With the present background levels of PCBs and OH-PCBs no negative correlations was found in testicular volume at 3 and 18 months. Although these endocrine disruptors are banned for several years and decreased over a ten years period in one geographical area in the Netherlands, we can still detect these pollutants in pregnant mothers and their infants. Efforts to decrease the contamination of this planet by manmade compounds, which might have negative effects on humans, therefore remains of great importance.