US EPA

2192753 

Journal Article 

Neurodevelopmental, immunological and endocrinological indices of perinatal human exposure to PCBs and dioxins 

Weisglas-Kuperus, N 

1996 

1 

NeuroToxicology
ISSN: 0161-813X
EISSN: 1872-9711 

17 

3-4 

945-946 

English 

is related to other volume(s) 199464 Neurodevelopmental, immunological and endocrinological indices of perinatal human exposure to PCBs and dioxins

Polychlorinated biphenyls (PCBs), PCDDs and PCDFs (summarized as dioxins) are potentially toxic compounds which occur widely in the environment. They are presently a pollution problem because they are resistant to either chemical or biologic degradation and they accumulate in the food chain. Perinatal PCB/dioxin exposure may affect neurodevelopmental and behavioral outcome in accidentally as well as in background prenatal exposed children, suggesting that the developing human brain is particularly sensitive to these compounds. Data regarding the potential immunotoxic effects of PCBs and dioxins in human beings remain scarce. Adult humans are less susceptible than perinatally exposed infants. Perinatal exposure to PCBs and dioxins at a high level may affect primary antibody response. Prenatal background exposure to PCBs and dioxins may result in changes in the T-cell population without effect on the health status of the infant nor on humoral immunity. In most studies a relation between PCB exposure and birthweight have been found. PCBs and dioxins provide inter- or intra-cellular signals that alter growth, differentiation and function of cells in a tissue-, stage-, or cell-specific manner. They have the potential to disrupt the endocrine system of animals as well as humans. Perinatal exposure to chemicals that mimics natural steroidal hormones can have a profound impact on later development of the reproductive system. Elevated levels of dioxins and PCB can also alter the human thyroid hormone status. Relatively subtle thyroid hormone alterations have been observed in pregnant mothers and their infants exposed to background levels of PCBs and dioxins. Thyroid hormones are needed to stimulate neuronal and glial proliferation and differentiation of the central nervous system. Androgens and estrogens can also alter the development of the central nervous system. The brain-pituitary-reproductive and thyroid Axis and the brain-thymus-lymphoid axis are linked by an array of internal mechanisms of communication that use similar signals (neurotransmitters, peptides, growth factors, hormones) acting on similar recognition targets. The construction of the physiological systems of the pituitary/hypothalamic region of the brain takes place in utero. At that time endocrine disruptors may be the most threatening, leading to changes in the endocrine, immune, and nervous systems and hypothalame function that do not respond to normal hormonal and neurotransmitter messages in the usual manner throughout life. In this presentation the key data concerning the effects of perinatal exposure to PCBs and dioxins on the endocrine, reproductive, immune and central nervous system in human infants and children will be described. The strengths and weakness of our current understanding and conflicting study data about the interaction between neural, immune and endocrine processes will be discussed.