Environmental toxicology: Sensitive periods of development and neurodevelopmental disorders

Research output: Contribution to JournalReview articleAcademicpeer-review

Abstract

Development of the mammalian central nervous system is a complex process whose disruption may have severe and long-lasting consequences upon brain structure and function, potentially resulting in a neurodevelopmental disorder (NDD). Many NDDs are known to be genetic in origin, with symptom onset and their underlying mechanisms now known to be regulated during time-dependent windows or 'critical periods' during normal brain development. However, it is increasingly evident that similar disturbances to the developing nervous system may be caused by exposure to non-genetic, environmental factors. Strikingly, at least 200 industrially applied or produced chemicals have been associated with neurotoxicity in humans and exposure to these modifying compounds, through consumer products or environmental pollution, therefore poses serious threats to public health. Through a combination of human epidemiological and animal experimental studies, we identified developmental periods for increased vulnerability to environmentally-modifying compounds and determined whether and how exposure during specific sensitive time-windows could increase the risk for the NDDs of autism, ADHD or schizophrenia in the developing organism. We report that many environmental toxicants have distinct sensitive time-windows during which exposure may disrupt critical developmental events, thereby increasing the risk of developing NDDs. The majority of these time-windows occur prenatally rather than postnatally. We propose four underlying mechanisms that mediate pathogenesis, namely oxidative stress, immune system dysregulation, altered neurotransmission and thyroid hormone disruption. Given the complexity of underlying mechanisms and their prenatal inception, treatment options are currently limited. Thus, we conclude that preventing early exposure to environmental toxicants, by increasing public awareness and improving government and industry guidelines, may ultimately lead to a significant reduction in the incidence of NDDs.

Original languageEnglish
Pages (from-to)23-41
Number of pages19
JournalNeurotoxicology
Volume58
DOIs
Publication statusPublished - Jan 2017

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Ecotoxicology
Neurology
Brain
Oxidative stress
Consumer products
Immune system
Public health
Thyroid Hormones
Animals
Pollution
Environmental Pollution
Environmental Exposure
Autistic Disorder
Synaptic Transmission
Nervous System
Immune System
Industry
Schizophrenia
Oxidative Stress
Central Nervous System

Keywords

  • Animals
  • Ecotoxicology
  • Environmental Pollution
  • Humans
  • Neurodevelopmental Disorders
  • Neurotoxicity Syndromes
  • Journal Article
  • Review

Cite this

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title = "Environmental toxicology: Sensitive periods of development and neurodevelopmental disorders",
abstract = "Development of the mammalian central nervous system is a complex process whose disruption may have severe and long-lasting consequences upon brain structure and function, potentially resulting in a neurodevelopmental disorder (NDD). Many NDDs are known to be genetic in origin, with symptom onset and their underlying mechanisms now known to be regulated during time-dependent windows or 'critical periods' during normal brain development. However, it is increasingly evident that similar disturbances to the developing nervous system may be caused by exposure to non-genetic, environmental factors. Strikingly, at least 200 industrially applied or produced chemicals have been associated with neurotoxicity in humans and exposure to these modifying compounds, through consumer products or environmental pollution, therefore poses serious threats to public health. Through a combination of human epidemiological and animal experimental studies, we identified developmental periods for increased vulnerability to environmentally-modifying compounds and determined whether and how exposure during specific sensitive time-windows could increase the risk for the NDDs of autism, ADHD or schizophrenia in the developing organism. We report that many environmental toxicants have distinct sensitive time-windows during which exposure may disrupt critical developmental events, thereby increasing the risk of developing NDDs. The majority of these time-windows occur prenatally rather than postnatally. We propose four underlying mechanisms that mediate pathogenesis, namely oxidative stress, immune system dysregulation, altered neurotransmission and thyroid hormone disruption. Given the complexity of underlying mechanisms and their prenatal inception, treatment options are currently limited. Thus, we conclude that preventing early exposure to environmental toxicants, by increasing public awareness and improving government and industry guidelines, may ultimately lead to a significant reduction in the incidence of NDDs.",
keywords = "Animals, Ecotoxicology, Environmental Pollution, Humans, Neurodevelopmental Disorders, Neurotoxicity Syndromes, Journal Article, Review",
author = "Heyer, {Djai B} and Meredith, {Rhiannon M}",
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year = "2017",
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doi = "10.1016/j.neuro.2016.10.017",
language = "English",
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Environmental toxicology : Sensitive periods of development and neurodevelopmental disorders. / Heyer, Djai B; Meredith, Rhiannon M.

In: Neurotoxicology, Vol. 58, 01.2017, p. 23-41.

Research output: Contribution to JournalReview articleAcademicpeer-review

TY - JOUR

T1 - Environmental toxicology

T2 - Sensitive periods of development and neurodevelopmental disorders

AU - Heyer, Djai B

AU - Meredith, Rhiannon M

N1 - Copyright © 2016 Elsevier B.V. All rights reserved.

PY - 2017/1

Y1 - 2017/1

N2 - Development of the mammalian central nervous system is a complex process whose disruption may have severe and long-lasting consequences upon brain structure and function, potentially resulting in a neurodevelopmental disorder (NDD). Many NDDs are known to be genetic in origin, with symptom onset and their underlying mechanisms now known to be regulated during time-dependent windows or 'critical periods' during normal brain development. However, it is increasingly evident that similar disturbances to the developing nervous system may be caused by exposure to non-genetic, environmental factors. Strikingly, at least 200 industrially applied or produced chemicals have been associated with neurotoxicity in humans and exposure to these modifying compounds, through consumer products or environmental pollution, therefore poses serious threats to public health. Through a combination of human epidemiological and animal experimental studies, we identified developmental periods for increased vulnerability to environmentally-modifying compounds and determined whether and how exposure during specific sensitive time-windows could increase the risk for the NDDs of autism, ADHD or schizophrenia in the developing organism. We report that many environmental toxicants have distinct sensitive time-windows during which exposure may disrupt critical developmental events, thereby increasing the risk of developing NDDs. The majority of these time-windows occur prenatally rather than postnatally. We propose four underlying mechanisms that mediate pathogenesis, namely oxidative stress, immune system dysregulation, altered neurotransmission and thyroid hormone disruption. Given the complexity of underlying mechanisms and their prenatal inception, treatment options are currently limited. Thus, we conclude that preventing early exposure to environmental toxicants, by increasing public awareness and improving government and industry guidelines, may ultimately lead to a significant reduction in the incidence of NDDs.

AB - Development of the mammalian central nervous system is a complex process whose disruption may have severe and long-lasting consequences upon brain structure and function, potentially resulting in a neurodevelopmental disorder (NDD). Many NDDs are known to be genetic in origin, with symptom onset and their underlying mechanisms now known to be regulated during time-dependent windows or 'critical periods' during normal brain development. However, it is increasingly evident that similar disturbances to the developing nervous system may be caused by exposure to non-genetic, environmental factors. Strikingly, at least 200 industrially applied or produced chemicals have been associated with neurotoxicity in humans and exposure to these modifying compounds, through consumer products or environmental pollution, therefore poses serious threats to public health. Through a combination of human epidemiological and animal experimental studies, we identified developmental periods for increased vulnerability to environmentally-modifying compounds and determined whether and how exposure during specific sensitive time-windows could increase the risk for the NDDs of autism, ADHD or schizophrenia in the developing organism. We report that many environmental toxicants have distinct sensitive time-windows during which exposure may disrupt critical developmental events, thereby increasing the risk of developing NDDs. The majority of these time-windows occur prenatally rather than postnatally. We propose four underlying mechanisms that mediate pathogenesis, namely oxidative stress, immune system dysregulation, altered neurotransmission and thyroid hormone disruption. Given the complexity of underlying mechanisms and their prenatal inception, treatment options are currently limited. Thus, we conclude that preventing early exposure to environmental toxicants, by increasing public awareness and improving government and industry guidelines, may ultimately lead to a significant reduction in the incidence of NDDs.

KW - Animals

KW - Ecotoxicology

KW - Environmental Pollution

KW - Humans

KW - Neurodevelopmental Disorders

KW - Neurotoxicity Syndromes

KW - Journal Article

KW - Review

U2 - 10.1016/j.neuro.2016.10.017

DO - 10.1016/j.neuro.2016.10.017

M3 - Review article

VL - 58

SP - 23

EP - 41

JO - Neurotoxicology

JF - Neurotoxicology

SN - 0161-813X

ER -