A case control study of gene environmental interaction in fetal growth restriction with special reference to organochlorine pesticides

Pesticide contamination of lactating mothers' milk in Latin America: a systematic review

OBJECTIVE

To identify the prevalence of contamination by pesticides and their metabolites in the milk of lactating mothers in Latin America.

METHODS

In this systematic review, the PubMed, LILACS, Embase, and Scopus databases were searched up to January 2022 to identify observational studies. The Mendeley software was used to manage these references. The risk of bias assessment was evaluated according to the checklist for prevalence studies and writing design, by the Prisma guidelines.

RESULTS

This study retrieved 1835 references and analyzed 49 studies. 69.38% of the analyzed studies found a 100% prevalence of breast milk contamination by pesticides among their sample. Main pesticides include dichlorodiphenyltrichloroethane (DDT) and its isomers (75.51%), followed by the metabolite dichlorodiphenyldichloroethylene (DDE) (69.38%) and hexachlorocyclohexane (HCH) (46.93%). This study categorized most (65.30%) studies as having a low risk of bias.

CONCLUSIONS

This review shows a high prevalence of pesticide contamination in the breast milk of Latin American women. Further investigations should be carried out to assess contamination levels in breast milk and the possible effects of these substances on maternal and child health.

Predictors of Maternal Serum Concentrations for Selected Persistent Organic Pollutants (POPs) in Pregnant Women and Associations with Birth Outcomes: A Cross-Sectional Study from Southern Malawi

Population exposure to persistent organic pollutants (POPs) may result in detrimental health effects, especially to pregnant women, developing foetuses and young children. We are reporting the findings of a cross-sectional study of 605 mothers in their late pregnancy, recruited between August 2020 and July 2021 in southern Malawi, and their offspring. The aim was to measure the concentrations of selected POPs in their maternal serum and indicate associations with social demographic characteristics and birth outcomes. A high level of education was the main predictor of p,p'-DDE (p = 0.008), p,p'-DDT (p < 0.001), cis-NC (p = 0.014), o,p'-DDT (p = 0.019) and o,p'-DDE (p = 0.019) concentrations in maternal serum. Multiparity was negatively associated with o,p'-DDE (p = 0.021) concentrations. Maternal age was also positively associated (p,p'-DDE (p = 0.013), o,p'-DDT (p = 0.017) and o,p'-DDE (p = 0.045) concentrations. Living in rural areas was inversely associated with high maternal serum concentrations of p,p'-DDT (p < 0.001). Gestational age was positively associated with p,p'-DDE (p = 0.031), p,p'-DDT (p = 0.010) and o,p'-DDT (p = 0.022) concentrations. Lastly, an inverse association was observed between head circumference and t-NC (p = 0.044), Oxychlordane (p = 0.01) and cis-NC (p = 0.048). These results highlight the need to continue monitoring levels of POPs among vulnerable populations in the southern hemisphere.

Gene-environment interactions related to maternal exposure to environmental and lifestyle-related chemicals during pregnancy and the resulting adverse fetal growth: a review

Background

There are only limited numbers of reviews on the association of maternal-child genetic polymorphisms and environmental and lifestyle-related chemical exposure during pregnancy with adverse fetal growth. Thus, this article aims to review: (1) the effect of associations between the above highlighted factors on adverse fetal growth and (2) recent birth cohort studies regarding environmental health risks.

Methods

Based on a search of the PubMed database through August 2021, 68 epidemiological studies on gene-environment interactions, focusing on the association between environmental and lifestyle-related chemical exposure and adverse fetal growth was identified. Moreover, we also reviewed recent worldwide birth cohort studies regarding environmental health risks.

Results

Thirty studies examined gene-smoking associations with adverse fetal growth. Sixteen maternal genes significantly modified the association between maternal smoking and adverse fetal growth. Two genes significantly related with this association were detected in infants. Moreover, the maternal genes that significantly interacted with maternal smoking during pregnancy were cytochrome P450 1A1 (CYP1A1), X-ray repair cross-complementing protein 3 (XRCC3), interleukin 6 (IL6), interleukin 1 beta (IL1B), human leukocyte antigen (HLA) DQ alpha 1 (HLA-DQA1), HLA DQ beta 1 (HLA-DQB1), and nicotinic acetylcholine receptor. Fetal genes that had significant interactions with maternal smoking during pregnancy were glutathione S-transferase theta 1 (GSTT1) and fat mass and obesity-associated protein (FTO). Thirty-eight studies examined the association between chemical exposures and adverse fetal growth. In 62 of the 68 epidemiological studies (91.2%), a significant association was found with adverse fetal growth. Across the studies, there was a wide variation in the analytical methods used, especially with respect to the genetic polymorphisms of interest, environmental and lifestyle-related chemicals examined, and the study design used to estimate the gene-environment interactions. It was also found that a consistently increasing number of European and worldwide large-scale birth cohort studies on environmental health risks have been conducted since approximately 1996.

Conclusion

There is some evidence to suggest the importance of gene-environment interactions on adverse fetal growth. The current knowledge on gene-environment interactions will help guide future studies on the combined effects of maternal-child genetic polymorphisms and exposure to environmental and lifestyle-related chemicals during pregnancy.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00033.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

EXPOSURE TO TOXIC AGROCHEMICALS AND DEVELOPMENT OF CONGENITAL MALFORMATIONS: A SCOPING REVIEW

ABSTRACT Objective: to assess whether maternal and paternal exposure to toxic agrochemicals throughout life causes congenital malformations. Method: a scoping review was carried out on the PUBMED, CINAHL, EBSCO, MEDLINE, LILACS, SciELO, BDENF, Web of Science and ATHENA databases between August and September 2019 and updated in December 2020. A cohort and case control study were included, which addressed the effects of parents' exposure throughout their lives to toxic agrochemicals which caused congenital malformation outcomes. Results: the review covered 32 studies published between 2005 and 2020. The main malformations presented are related to the reproductive system, nervous system, musculoskeletal system, transverse limb deficiencies, digestive system and other malformations such as fetal growth restrictions, cleft palate and congenital heart disease. The most investigated toxic agrochemicals in the studies were the herbicides represented by atrazine. Conclusion: maternal and paternal exposure to toxic agrochemicals can be associated with greater chances of children being born with congenital malformations, especially those related to the male reproductive system.

Glutathione S-transferase activity and genetic polymorphisms associated with exposure to organochloride pesticides in Todos Santos, BCS, Mexico: a preliminary study

The objective of this study was to identify and evaluate the impact of exposure to mixtures of organochloride pesticides (OCPs) in agricultural workers by detecting their effects on the activity of the enzyme glutathione S-transferase (GST) and the presence of polymorphisms of the GSTT1 and GSTM1 genes. The presence of OCPs was identified and quantified by gas chromatography, while spectrophotometry was used to measure enzymatic GST activity. The frequencies of the GSTM1 genotypes were analyzed by multiplex PCR. A total of 18 metabolites of OCPs were identified in the workers' blood, most of which are either prohibited (DDT and its metabolites p, p'DDD and p, p'DDE, dieldrin, endrin, aldrin) and/or restricted (δ hexachlorocyclohexane, cis chlordane, methoxychlor, and endosulfan). The results obtained indicate lower levels of GST activity at higher OCPs concentrations detected in blood from exposed workers, together with an increase in OCP levels in individuals who presented the GSTT1*0 and GSTM1*0 genotypes. These conditions place the detoxification process in agricultural workers with null polymorphisms in the GST genes and high concentrations of OCPs in the blood (especially DDT and its metabolites, DDD and DDE) at risk, and increase their susceptibility to develop serious diseases.

Pesticide Risk and Recurrent Pregnancy Loss in Females of Subhumid Region of India

Objective:

The objective of this study is to determine the level of pesticides and their role in cases of recurrent pregnancy loss (RPL).

Materials and Methods:

This was designed as a case–control study. Gas chromatography was used to characterize the pesticide level in 70 cases and 70 controls. Case refers to women with RPL, whereas controls refer to women with full-term delivery.

Results:

A higher level of pesticide, namely beta-hexachlorocyclohexane, malathion, chlorpyrifos, and fenvalerate was found in the case group as compared to control group (P < 0.05).

Conclusions:

The present study suggests that high exposure of pesticide (organochlorine and organophosphates) may increase the risk of RPL in females of the subhumid region of India.

Multiple pesticides in mothers' hair samples and children's measurements at birth: Results from the French national birth cohort (ELFE)

BACKGROUND

A growing body of studies now suggests that the general population is continuously and ubiquitously exposed to numerous pesticides. However, studies investigating the possible role of environmental exposure to pesticides on fetal growth have focused on a limited set of substances, despite the hundreds of modern pesticides currently available.

AIM

To explore the relation between maternal hair concentrations of 64 pesticides and metabolites and their newborns' measurements at birth, with data from the ELFE French nationwide birth cohort.

METHODS

We measured 64 compounds (10-100% detection) in bundles of hair 9 cm long collected at birth from 311 women who gave birth in France in 2011. We assessed their associations with birth weight, length, and head circumference, adjusted for potential confounders, and used elastic net regularization to simultaneously select the strongest predictors of measurements at birth. Selected variables were multiply imputed for missing values, and unpenalized estimators were assessed by standard linear regression.

RESULTS

We observed statistically significant associations between maternal hair concentrations of seven pesticides or pesticide metabolites and birth measurements (weight: fipronil sulfone; length: TCPy, bitertanol, DEP, and isoproturon; head circumference: tebuconazole and prochloraz). Analyses restricted to boys identified 12 additional compounds: 8 independently associated with birth weight (3Me4NP, DCPMU, DMST, fipronil, mecoprop, propoxur, fenhexamid, and thiabendazole), 2 with birth length (dieldrin and β-endosulfan), and 6 with head circumference (β-endosulfan, β-HCH, fenuron, DCPMU, propoxur, and thiabendazole).

CONCLUSION

Our results suggest that prenatal exposure to 19 pesticides or metabolites from various chemical families may influence measurements at birth. As with any exploratory research findings, results should be interpreted cautiously, until they are replicated or verified by further epidemiological or mechanistic studies.

Association of maternal xenobiotic-metabolizing gene polymorphisms with risk of fetal growth restriction

Aim: We investigated the association of maternal CYP1A1 MspI, CYP1A1 Ile462Val, GSTT1 null, GSTM1 null and NQO1 Pro187Ser polymorphisms with fetal growth restriction risk. Methods: The polymorphisms were genotyped on 1842 mothers (N = 921 with fetal growth restriction and N = 921 controls). Odds ratios were calculated to estimate the risk. Results: None of the five polymorphisms were associated with risk of fetal growth restriction among never-smoker mothers. However, the variant genotypes of CYP1A1 MspI and GSTM1 null polymorphisms were associated with an increased risk of fetal growth restriction among mothers who were either passive or active smokers. Conclusion: CYP1A1 MspI and GSTM1 null polymorphisms may interact with cigarette smoking to result in an increased risk of fetal growth restriction.

Genetic polymorphisms as determinants of pesticide toxicity: Recent advances

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Genetic polymorphisms may influence pesticides-induced oxidative damage.Pesticides modulate immune-system cells functionality, leading to the onset of a dangerous pro-inflammatory microenvironment.

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DNA repair genes, Cytochrome P450 s, PON and GST genes have a key role in the metabolism of xenobiotics.

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Many workers are professionally exposed to pesticides with potential health consequences.

Occupational and environmental exposure to pesticides may induce harmful effects on human health by promoting the development of a wide range of disorders. Some of the most recently hypothesized mechanisms are oxidative stress and epigenetic modifications, however biological effects seem to be modulated mainly by the occurrence of genetic polymorphisms. The susceptibility to exposure can be evaluated by studying the most common polymorphisms of genes involved in the metabolism of organophosphorus compounds (cytochrome P450, glutathione transferase, acetyltransferases or paraoxonase 1). The aim of this article is to review recent literature data concerning the influence of genetic polymorphisms on pesticides-induced oxidative damage.

Glutathione S-transferase M1 and T1 polymorphisms, and their interactions with smoking on risk of low birth weight: a meta-analysis

Background: Published data regarding the association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) gene polymorphisms and risk of low birth weight (LBW) remains inconclusive, and data on the interactions between the two gene polymorphisms and smoking for LBW susceptibility is lacking. To clarify these associations, a meta-analysis was conducted.Methods: A comprehensive literature search was conducted in multiple databases until 11 January 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed or random effects model.Results: Thirty-eight studies from 17 articles concerning maternal and neonatal GSTM1 and GSTT1 gene polymorphism with LBW risk were included in this meta-analysis, and nine studies from five articles provided data of maternal tobacco exposure status during pregnancy. Maternal GSTM1 null genotype was associated with increased LBW risk (OR = 1.27, 95% CI: 1.12-1.45). There was a nonsignificant but positive association (OR = 1.19, 95% CI: 0.97-1.46) between the maternal GSTT1 null genotype and the LBW risk in the overall analysis. There was a null association between neonatal GSTM1 or GSTT1 polymorphism and LBW risk. There were significant associations between the maternal GSTM1 null and GSTT1 null genotype and LBW risk (for the former, OR = 3.85, 95% CI: 1.68-8.81; for the later, OR = 1.88, 95% CI: 1.01-3.50) in individuals with active smoking, respectively.Conclusion: Maternal GSTM1 and GSTT1 null genotypes, but not neonatal genotypes, are suggested to increase LBW susceptibility, and there are interactions between active smoking and these polymorphisms in the development of LBW.

Association between Organochlorine Pesticide Levels in Breast Milk and Their Effects on Female Reproduction in a Taiwanese Population

Only few studies have focused on organochlorine pesticides (OCPs) in breast milk and the related health risks for women in Taiwan. Our goal is to examine breast milk OCPs and their associations with female reproductive function (infertility, gynecological diseases, and menstruation characteristics) as well as their correlation with sociodemographic parameters (age, pre-pregnant body mass index (BMI), annual incomes, population, birth year, and parity) and dietary habit. The breast milk samples were collected in southern Taiwan (n = 68) from 2013 to 2016 and the OCP residues were analyzed using high resolution gas chromatography with low resolution mass spectrometry (HRGC/LRMS). The results show that the most abundant OCP residues in the breast milk was ΣDDT with the geometric mean ± standard deviation of 9.81 ± 7.52 ng⁻¹ lipid⁻¹ followed by ΣHCH (0.539 ± 0.557 ng⁻¹·lipid⁻¹). In the principal component analysis, cis-chlordane (cis-CHL) and γ-HCH were found to be related to participants who received medical treatment for infertility, and 4,4′-DDT was associated with those who received gynecological surgery. The logistic regression showed that the odds ratio (OR) of log γ-hexachlorocyclohexane (γ-HCH) was higher for mothers who had received medical treatment for infertility than for the normal group (OR = 25.6, p = 0.035) after adjustments for age, pre-pregnant BMI, annual income, population (i.e., native-born Taiwanese), birth year, and parity. Cow milk and beef consumption as well as menstruation characteristics such as average menstrual period (>5 days), shortest menstrual period (<3 days), and women who had taken hormonal drugs were significantly associated to several OCP residues in the breast milk. In addition, ΣHCH including β-HCH and γ-HCH was correlated with annual family income and gravidity as well as cow milk and beef consumptions. Overall, γ-HCH exhibited a probable association with the infertility diseases of Taiwanese women, and dietary habit might play an important role in the female Taiwanese exposure to OCPs.

Modulatory role of GSTT1 and GSTM1 in Punjabi agricultural workers exposed to pesticides

Glutathione S-transferases are important detoxification enzymes involved in the metabolism of endogenous as well as exogenous compounds. Individuals differ in metabolic capacity due to inherited genetic variations. Due to the polymorphism exhibited by GSTT1 and GSTM1 that results in the complete loss of function, the present study was aimed towards the determination of the frequency distribution of GSTT1 and GSTM1 in agricultural workers in Punjab, India. The study aimed to investigate their contribution in susceptibility to increased disease risk. A total of 513 subjects were included in this study, out of which 250 were agriculture workers and 263 were non-exposed occupationally. GSTT1 and GSTM1 null-genotype distribution was analyzed through multiplex-PCR method. Complete gene deletion in either of the genes was strongly associated with an increased risk (OR = 1.8; 95% CI = 1.3-2.6; p < 0.0008) of DNA/cytogenetic damage, cancer, infertility, and many other serious health effects. Therefore, homozygous deletion in GSTT1 or GSTM1 could play a modulatory role in health of workers with long-term exposure to pesticides.

Assessment of protective potential of Nigella sativa oil against carbendazim- and/or mancozeb-induced hematotoxicity, hepatotoxicity, and genotoxicity

Nigella sativa oil (NSO) possesses antioxidant activity. However, its protective role against the hazards of fungicides has been poorly studied. Therefore, the present work aimed at determining the ameliorative potential of NSO against hepatotoxicity induced by carbendazim (CBZ) and/or mancozeb (MNZ) in female rats. In the present study, about 120 adult female Sprague-Dawley rats were randomly divided into eight equal groups. One group of animals was kept as a negative control (Gp. 1); groups 2, 3 and 4 orally received CBZ (200 mg/kg body wt) and/or MNZ (300 mg/kg body wt) daily for 2 weeks (positive groups). In order to assess the hepatoprotective potential of NSO, in comparison with NSO-treated rats (Gp. 5), groups 6, 7 and 8 were CBZ- and/or MNZ-exposed groups pre-treated orally with NSO (2 ml/kg body wt) daily for 2 weeks (prophylactic groups). All groups were kept further for 15 days without medications to observe the withdrawal effect. At the end of exposure and withdrawal periods, the body weight of all experimental rats was recorded and blood samples were collected for hematological, clinico-biochemical, and micronucleus assays. The animals were then sacrificed, and the liver and bone marrow were harvested for oxidative stress bioassay, chromosomal aberrations, DNA fragmentation, and histopathological examinations. The results suggested that pre-treatment with NSO remarkably diminished CBZ- and MNZ-induced macrocytic hypochromic anemia, leukocytosis, lymphocytosis, eosinophilia, and neutropenia. Besides, it also minimized the elevated liver enzymes, lipid peroxidation, micronucleus incidence, DNA damage, and chromosomal aberration frequency. Conversely, NSO significantly stimulated the CBZ- and/or MNZ-induced antioxidant system suppression. The NSO also normalized the hepatic structural architecture. As far as withdrawal effect is concerned, there was almost disappearance of the bad effects of these fungicides and the values were close to the normal range especially with the use of NSO. Ultimately, the results revealed that N. sativa oil is an effective hepatoprotective agent due to its genoprotective and free radical scavenging activities.

CYP1A1 expression and organochlorine pesticides level in the etiology of bladder cancer in North Indian population

Urinary bladder cancer (UBC) is one of the most common malignancies worldwide. The etiology of UBC is multifactorial and includes both exogenous and endogenous factors. Exogenous risk factors include exposure to heavy metals, aromatic amines, and environmental pollutants including pesticides such as organochlorine pesticides (OCPs). Environmental factors alone are incapable of directly producing DNA damage and may require activation by phase I metabolizing enzymes like cytochrome P450 in order to become active carcinogen. The present study is designed to study CYP1A1 gene expression, OCP level in cases of UBC, as well as to explore the plausible role of gene–environment interaction in the etiology of UBC among North Indian population. A total of 60 cases with equal number of controls were enrolled under this study, the OCP levels were estimated using gas chromatography, CYP1A1 mRNA expression was quantified by real-time quantitative polymerase chain reaction, and fold change was calculated using the ΔΔCt method. In the present study, the levels of OCP were found to be significantly higher with the upregulation of CYP1A1 mRNA expression among UBC cases as compared to controls. While putting multiple linear regression, it has been observed that there is a significant interaction between the levels of OCPs and ΔCt value of CYP1A1 gene taken into account hematuria episodes as dependent variable. The study concludes that when there is predisposition of OCPs and upregulation of CYP1A1 gene, then the result will be an increment in hematuria episodes which indicates that gene–environment interaction plays a significant role in the causation of UBC among North Indian population.

A comparison of the effects of lindane and FeCl3/ADP on spontaneous contractions in isolated rat or human term myometrium

Oxidative stress affects the contractile behavior of smooth muscle resulting in complications during labor. Toxicants such as lindane and ferric chloride (FeCl₃)/adenosine diphosphate (ADP) cause oxidative stress and have previously been shown to inhibit smooth muscle contraction. In this study we examined the effects of the oxygen species scavengers, ascorbic acid and N-acetylcysteine on lindane and FeCl₃/ADP's inhibition of spontaneous myometrial contractions in rat and human myometrium. Lindane and FeCl₃/ADP gave rise to concentration-dependent reductions in rat (EC₅₀ 11.8×10^-6M and 0.9×10^-3M) and human myometrial contractions (EC₅₀ 16.3×10^-6M and 1.1×10^-3M, respectively). Pre-treatment with N-acetylcysteine significantly increased the EC₅₀ for the effects of lindane on motility index of human tissue and reduced the maximum inhibitory effect of FeCl₃/ADP on contractions in both rat and human myometrium. Ascorbic acid reduced the effects of FeCl₃/ADP in rat tissue only. In conclusion pre-treatment with specific antioxidants may protect both rat and human myometrium from the inhibitory effects of lindane and FeCl₃/ADP.

Interaction between β-hexachlorocyclohexane and ADIPOQ genotypes contributes to the risk of type 2 diabetes mellitus in East Chinese adults

Growing evidence links environmental exposure to hexachlorocyclohexanes (HCHs) to the risk of type 2 diabetes mellitus (T2DM), and ADIPOQ that encodes adiponectin is considered as an important gene for T2DM. However, the role of ADIPOQ-HCH interaction on T2DM risk remains unclear. Thus, a paired case-control study was conducted in an East Chinese community. A total of 1446 subjects, including 723 cases and 723 controls matched on age, gender and residence, were enrolled, and 4 types of HCH isomers were measured in serum samples using GC-MS/MS. Additionally, 4 candidate ADIPOQ SNPs (rs182052, rs266729, rs6810075, and rs16861194) were genotyped by TaqMan assay, and plasma adiponectin was measured using ELISA. No associations between 4 SNPs and T2DM risk were found, but T2DM risk significantly increased with serum levels of β-HCH (P < 0.001). Furthermore, the synergistic interaction between β-HCH and rs182052 significantly increased T2DM risk (OR _{I-additive model} = 2.20, OR _{I-recessive model} = 2.13). Additionally, individuals carrying only rs182052 (A allele) with high levels of β-HCH had significant reduction in adiponectin levels (P = 0.016). These results indicate that the interaction between rs182052 and β-HCH might increase the risk of T2DM by jointly decreasing the adiponectin level and potentially trigger T2DM development.

Passive rGE or Developmental Gene-Environment Cascade? An Investigation of the Role of Xenobiotic Metabolism Genes in the Association Between Smoke Exposure During Pregnancy and Child Birth Weight

There is considerable evidence that smoke exposure during pregnancy (SDP) environmentally influences birth weight after controlling for genetic influences and maternal characteristics. However, maternal smoking during pregnancy-the behavior that leads to smoke exposure during pregnancy-is also genetically-influenced, indicating the potential role of passive gene-environment correlation. An alternative to passive gene-SDP correlation is a cascading effect whereby maternal and child genetic influences are causally linked to prenatal exposures, which then have an 'environmental' effect on the development of the child's biology and behavior. We describe and demonstrate a conceptual framework for disentangling passive rGE from this cascading GE effect using a systems-based polygenic scoring approach comprised of genes shown to be important in the xenobiotic (substances foreign to the body) metabolism pathway. Data were drawn from 5044 families from the Avon Longitudinal Study of Parents and Children with information on maternal SDP, birth weight, and genetic polymorphisms in the xenobiotic pathway. Within a k-fold cross-validation approach (k = 5), we created weighted maternal and child polygenic scores using 18 polymorphisms from 10 genes that have been implicated in the xenobiotic metabolism pathway. Mothers and children shared variation in xenobiotic metabolism genes. Amongst mothers who smoked during pregnancy, neither maternal nor child xenobiotic metabolism polygenic scores were associated with a higher likelihood of smoke exposure during pregnancy, or the severity of smoke exposure during pregnancy (and therefore, neither proposed mechanism was supported), or with child birth weight. SDP was consistently associated with lower child birth weight controlling for the polygenic scores, maternal educational attainment, social class, psychiatric problems, and age. Limitations of the study design and the potential of the framework using other designs are discussed.

The Association between Gene-Environment Interactions and Diseases Involving the Human GST Superfamily with SNP Variants

Exposure to environmental hazards has been associated with diseases in humans. The identification of single nucleotide polymorphisms (SNPs) in human populations exposed to different environmental hazards, is vital for detecting the genetic risks of some important human diseases. Several studies in this field have been conducted on glutathione S-transferases (GSTs), a phase II detoxification superfamily, to investigate its role in the occurrence of diseases. Human GSTs consist of cytosolic and microsomal superfamilies that are further divided into subfamilies. Based on scientific search engines and a review of the literature, we have found a large amount of published articles on human GST super- and subfamilies that have greatly assisted in our efforts to examine their role in health and disease. Because of its polymorphic variations in relation to environmental hazards such as air pollutants, cigarette smoke, pesticides, heavy metals, carcinogens, pharmaceutical drugs, and xenobiotics, GST is considered as a significant biomarker. This review examines the studies on gene-environment interactions related to various diseases with respect to single nucleotide polymorphisms (SNPs) found in the GST superfamily. Overall, it can be concluded that interactions between GST genes and environmental factors play an important role in human diseases.

Gestational Hypertension and Organophosphorus Pesticide Exposure: A Cross-Sectional Study

Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies. High blood pressure (BP) with diastolic BP ≥ 90 mm Hg and/or systolic BP ≥ 140 mm Hg arising after week 22 of pregnancy and resolving after delivery is defined as gestational hypertension (GHY). The aim of this cross-sectional study was to investigate whether occupational and/or environmental exposure to organophosphorus (OP) pesticide affects GHY. Women at approximately 22 weeks of gestation were recruited. OP pesticide exposure in the first trimester of pregnancy was classified into four categories: no exposure, indirect exposure, domestic exposure, and occupational exposure. Application of the exclusion criteria left 2203 participants (mean age 30.4 ± 11.6 years). Data analysis showed that in women with indirect OP pesticide exposure the incidence of GHY was slightly higher than that in the world population, whereas domestic exposure involved a 7% increase and occupational exposure a 12% increase. Analysis of the pesticides used by participants highlighted a possible role for malathion and diazinon (adjusted OR 1.09 and 1.14, resp.). Further investigation of exposed workers and the general population is clearly warranted given the broad diffusion of OP pesticides and their possible public health impact, maybe by including a wider range of health outcomes.

Organochlorine pesticide levels in maternal blood and placental tissue with reference to preterm birth: a recent trend in North Indian population

Organochlorine pesticides (OCPs) have been widely used in public health and agriculture programs in developed as well as developing countries, including India. Being xenoestrogenic in nature, OCPs may act as endocrine disruptors leading to preterm birth (PTB) through disturbance of normal estrogen-progesterone ratio. PTB is the leading cause of neonatal deaths worldwide. Therefore, the present study is aimed to determine the extent to which persistent environmental chemicals may accumulate in pregnant women and placenta and ascertain possible associations between exposure level and period of gestation (POG), baby weight, and/or placental weight in PTB cases. Maternal blood and placenta samples of PTB cases (n = 50) and subjects of term delivery as controls (n = 50) were collected. OCP residue levels were estimated by the gas chromatography system equipped with an electron capture detector. Significantly higher levels of α-hexachlorocyclohexane (α-HCH), β-hexachlorocyclohexane (β-HCH), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE) were found in maternal blood of PTB cases as compared to control. Significantly higher levels of DDE and dichlorodiphenyltrichloroethane (DDT) were also found in placental tissue of PTB cases as compared to control group. There was a statistically significant negative correlation between maternal blood level of α-HCH and birth-weight (r = -0.299) and POG (r = -0.234). γ-Hexachlorocyclohexane (γ-HCH) and dieldrin had a negative correlation with placental weight (r = -0.401 and -0.256, respectively), and DDE and β-HCH had a negative correlation with POG (r = -0.251 and -0.229, respectively). The presence of OCPs in maternal blood and placental tissue represents prenatal exposure hazard for fetuses due to chronic bioaccumulation and poor elimination with possible deleterious effect on health.

Persistent organochlorine pesticides and oxidant/antioxidant status in the placental tissue of the women with full-term and pre-term deliveries

In India pre-term birth is the leading cause of death of infants and this number is continuously increasing.

CYP17A1 gene polymorphisms and environmental exposure to organochlorine pesticides contribute to the risk of small for gestational age

OBJECTIVES

The cytochrome P-450c17α enzyme encoded by the cytochrome P-450c17α (CYP17A1) gene plays a role in oestrogen synthesis. Genetic variation in the maternal CYP17A1 gene leads to differences in oestrogen level that affect fetal growth and cause small for gestational age (SGA). Organochlorine pesticides (OCPs) are endocrine disruptors that alter the normal oestrogen-progesterone balance, and are associated with adverse reproductive outcomes. This study was designed to investigate the effect of the gene-environment interaction between maternal CYP17A1 gene polymorphisms and maternal and cord OCP levels on the risk of SGA.

STUDY DESIGN

Maternal and cord blood samples of 50 term SGA cases (birth weight <10th percentile for gestational age as per Lubchenco's growth chart) and 50 normal pregnancies (controls) were collected. Women with occupational exposure to OCPs, anaemia, hypertension, antiphospholipid antibody syndrome, medical disease, parity of more than four, or a history of smoking, alcohol consumption or chronic drug intake were excluded from both groups. Maternal and cord blood samples were collected at the time of delivery or after delivery, respectively. The OCP levels of the samples were analyzed using a gas chromatography system equipped with an electron capture detector, and polymerase chain reaction-restriction fragment length polymorphism was used for polymorphic analysis of the CYP17A1 gene.

RESULTS

Significantly (p<0.05) higher levels of α-hexachlorocyclohexane (HCH), β-HCH and γ-HCH were found in maternal and cord blood samples of the SGA cases compared with the controls. The frequency of the A1A2/A2A2 genotype was significantly lower [p=0.041, odds ratio (OR) 0.421, 95% confidence interval (CI) 0.184-0.966] in the SGA cases compared with the controls. When gene-environment interactions between CYP17A1 gene polymorphisms and OCP levels were considered, a significant (p=0.004) association was found between a high level of endosulfan in cord blood and the A1A1 (wild-type) genotype of CYP17A1, leading to an estimated reduction in birth weight of 315g.

CONCLUSIONS

Higher OCP levels and the A1A1 genotype of CYP17A1 in pregnant women may be considered as important aetiological factors in idiopathic SGA. This study provides evidence that genetic variation and its interaction with environmental exposure may increase the risk of SGA. Further studies are needed with a larger sample size, incorporating other gene polymorphisms and environmental exposures, to strengthen these observations.

Role of early life exposure and environment on neurodegeneration: implications on brain disorders

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and retinal degeneration have been studied extensively and varying molecular mechanisms have been proposed for onset of such diseases. Although genetic analysis of these diseases has also been described, yet the mechanisms governing the extent of vulnerability to such diseases remains unresolved. Recent studies have, therefore, focused on the role of environmental exposure in progression of such diseases especially in the context of prenatal and postnatal life, explaining how molecular mechanisms mediate epigenetic changes leading to degenerative diseases. This review summarizes both the animal and human studies describing various environmental stimuli to which an individual or an animal is exposed during in-utero and postnatal period and mechanisms that promote neurodegeneration. The SNPs mediating gene environment interaction are also described. Further, preventive and therapeutic strategies are suggested for effective intervention.

Environmental pollutants and lifestyle factors induce oxidative stress and poor prenatal development

Developmental toxicity caused by exposure to a mixture of environmental pollutants has become a major health concern. Human-made chemicals, including xenoestrogens, pesticides and heavy metals, as well as unhealthy lifestyle behaviours, mainly tobacco smoking, alcohol consumption and medical drug abuse, are major factors that adversely influence prenatal development and increase susceptibility of offspring to diseases. There is evidence to suggest that the developmental toxicological mechanisms of chemicals and lifestyle factors involve the generation of reactive oxygen species (ROS) and cellular oxidative damage. Overproduction of ROS induces oxidative stress, a state where increased ROS generation overwhelms antioxidant protection and subsequently leads to oxidative damage of cellular macromolecules. Data on the involvement of oxidative stress in the mechanism of developmental toxicity following exposure to environmental pollutants are reviewed in an attempt to provide an updated basis for future studies on the toxic effect of such pollutants, particularly the notion of increased risk for developmental toxicity due to combined and cumulative exposure to various environmental pollutants. The aims of such studies are to better understand the mechanisms by which environmental pollutants adversely affect conceptus development and to elucidate the impact of cumulative exposures to multiple pollutants on post-natal development and health outcomes. Developmental toxicity caused by exposure to mixture of environmental pollutants has become a major health concern. Human-made chemicals, including xenoestrogens, pesticides and heavy metals, as well as unhealthy lifestyle behaviors, mainly tobacco smoking, alcohol consumption and medical drug abuse, are major factors that adversely influence prenatal development and increase the susceptibility of offspring to development complications and diseases. There is evidence to suggest that the developmental toxicological mechanisms of human-made chemicals and unhealthy lifestyle factors involve the generation of reactive oxygen species (ROS) and cellular oxidative damage. Overproduction of ROS induces oxidative stress, a state where increased generation of ROS overwhelms antioxidant protection and subsequently leads to oxidative damage of cellular macromolecules. Exposure to various environmental pollutants induces synergic and cumulative dose-additive adverse effects on prenatal development, pregnancy outcomes and neonate health. Data from the literature on the involvement of oxidative stress in the mechanism of developmental toxicity following in vivo exposure to environmental pollutants will be reviewed in an attempt to provide an updated basis for future studies on the toxic effect of such pollutants, particularly the notion of increased risk for developmental toxicity due to combined and cumulative exposure to various environmental pollutants. The aims of such studies are to better understand the mechanisms by which environmental pollutants adversely affect conceptus development and to elucidate the impact of cumulative exposures to multiple pollutants on postnatal development and health outcomes.

Maternal predictors of intrauterine growth restriction

PURPOSE OF REVIEW

Intrauterine growth restriction (IUGR) occurs when fetal growth rate falls below the genetic potential and affects a significant number of pregnancies, but still no therapy has been developed for this pregnancy disease. This article reviews the most recent findings concerning maternal characteristics and behaviours predisposing to IUGR as well as maternal early markers of the disease. A comprehensive understanding of factors associated with IUGR will help in providing important tools for preventing and understanding adverse outcomes.

RECENT FINDINGS

Maternal nutritional status, diet and exposure to environmental factors are increasingly acknowledged as potential factors affecting fetal growth both by altering nutrient availability to the fetus and by modulating placental gene expression, thus modifying placental function.

SUMMARY

Assessing nutritional and environmental factors associated with IUGR, and the molecular mechanisms by which they may have a role in the disease onset, is necessary to provide comprehensive and common guidelines for maternal care and recommended behaviours. Moreover, maternal genetic predispositions and early serum markers may allow a better and more specific monitoring of high risk pregnancies, optimizing the timing of delivery.