Céline Campagna

Impaired Maturation, Fertilization, and Embryonic Development of Porcine Oocytes Following Exposure to an Environmentally Relevant Organochlorine Mixture

Abstract The reproductive health risks related to exposure to persistent organic pollutants in the environment remain controversial. This debate is partly because most studies have investigated only one or two chemicals at a time, whereas populations are exposed to a large spectrum of persistent chemicals in their environment. Using the pig as a toxicological model, we hypothesized that exposing immature cumulus-oocyte complexes to an organochlorine mixture during in vitro maturation (IVM) would adversely affect oocyte maturation, fertilization, and subsequent embryo development. This organochlorine mixture mimics that which contaminates the Arctic marine food chain. Cumulus-oocyte complexes were cultured in IVM medium containing increasing concentrations of the organochlorine mixture, similar to that found in women of highly exposed populations. Organochlorines reduced the quality of cumulus expansion and the viability of cumulus cells in a dose-response manner. The proportion of apoptotic cumulus cells also increased due to organochlorine exposure. Half of the oocytes were fixed after insemination, and the remainders were cultured for 8 days. Concentrations of organochlorines did not affect the rates of oocyte degeneration, sperm penetration, and development to morula. However, incidence of incompletely matured oocytes increased and polyspermy rate decreased, both in a dose-response manner with increasing organochlorine concentrations. Blastocyst formation and number of cells per blastocyst declined with organochlorine concentration. Exposing porcine cumulus-oocyte complexes to an environmentally pertinent organochlorine mixture during IVM disturbs oocyte development, supporting recent concerns that such pollutants harm reproductive health in humans and other mammalian species.

An environmentally relevant organochlorine mixture impairs sperm function and embryo development in the porcine model.

Abstract We evaluated the effects of an environmentally relevant mixture of more than 15 organochlorines on the development of pig oocytes and sperm during in vitro fertilization (IVF). Oocytes were cocultured with sperm in IVF medium containing increasing concentrations of an organochlorine mixture, similar to that found in women of highly exposed populations. Exposure to the organochlorine mixture diminished oocyte penetration rates and polyspermy in a linear manner. The mixture did not affect rates of cleavage nor development to multicell embryos. However, rates of development to the blastocyst stage were lower at the highest concentration at which oocyte penetration was observed. The same experiment was performed using oocytes that were preexposed during in vitro maturation. This greater exposure to the mixture also reduced penetration in a dose-response manner and affected polyspermy. Frozen-thawed pig sperm were also cultured in IVF medium containing the same organochlorine concentrations. Sperm motility parameters were immediately reduced in a dose-dependant manner by the organochlorines, followed by diminished viability 2 h later. From these results, it appears that reduced sperm quality would account for decreases in fertilization, polyspermy, and blastocyst formation. These results suggest that exposing porcine oocytes and sperm to an environmentally pertinent organochlorine mixture in vitro disrupts the oocyte block to polyspermy, sperm fertility, and further embryonic development, and supports recent concerns that such pollutants harm reproductive health in humans and other species.

The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1–5 years in Montréal (Québec, Canada)

Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1–10.2). Windowsill dust loading >14.1 μg/ft2 was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3–7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

Effects of an environmentally relevant organochlorine mixture and a metabolized extract of this mixture on porcine sperm parameters in vitro.

Organochlorine chemicals are present in the environment worldwide; however, populations living in the Far North are particularly at risk because their traditional diets are mainly composed of contaminated animals (fish, seals, whales, and polar bears). It has been suggested that male fertility is globally declining, possibly because of chronic, low-level exposure to environmental contaminants. This study was designed to assess the effects on fresh sperm fertility parameters using the porcine model of 1) an environmentally relevant mixture of 15 organochlorines and 2) the metabolized extract of this mixture. In the first experiment, the organochlorine mixture (at relative concentrations of 10.5, 14.7, and 21 microg/mL polychlorinated biphenyls [PCBs]) reduced sperm total motility, progressive motility, and viability, and increased capacitation, spontaneous acrosome reaction rates, and cytosolic calcium levels, suggesting that the mixture alters the sperm membrane and is detrimental to sperm function. In the second experiment, the metabolized extract of this organochlorine mixture (at relative concentrations of 0.9, 1.8, 2.7, 3.6, and 4.5 microg/L OH-PCBs) tended to decrease only sperm total motility. In an in vitro porcine model, the mixture of organochlorines, as found in the Arctic food chain, was rapidly detrimental to sperm function at concentrations above environmental levels. In contrast, short and physiologically relevant exposure to the metabolized extract of this mixture induced only limited adverse effects on sperm motility.

Inactivation of dairy bacteriophages by commercial sanitizers and disinfectants.

Many commercial sanitizers and disinfectants have been used over the years to control microbial contamination but their efficacy on phages is often unknown. Here, 23 commercial chemical products, including 21 food-grade sanitizers were tested against virulent dairy phages. These food-grade chemicals included oxidizing agents, halogenated agents, alcohols, quaternary ammonium compounds, anionic acids, iodine-based acids, and an amphoteric chemical. Phage P008 was first exposed to each sanitizer for 2 and 15min at room temperature and at two different concentrations, namely the lowest and highest no-rinse sanitizing concentrations. Organic matter (whey or milk) was also added to the testing solutions. At the end of the exposure period, the test solution was neutralized and the number of infectious phages was determined by plaque assays. The five most efficient sanitizers against phage P008 (<4 log of inactivation) were then tested against virulent lactococcal phages P008, CB13, AF6, P1532 of the 936 group, P001 (c2), Q54, and 1358 as well as Lactobacillus plantarum phage B1 and Streptococcus thermophilus phage 2972 using the same protocol. The oxidizing agents and the quaternary ammonium compounds were the most efficient against all phages although phages CB13 and P1532 were less sensitive to these chemicals than the other phages. This study may help in the selection of appropriate chemicals for controlling phage contamination in industrial factories and research laboratories.

An environmentally relevant mixture of organochlorines, their metabolites and effects on preimplantation development of porcine embryos

Environmental exposure of human populations to organochlorines is still widespread despite several international regulations banning or restricting their use. This study tested the hypothesis that an environmentally relevant complex mixture of organochlorines comprising polychlorinated biphenyls (PCBs), technical chlordane, dichlorodiphenyldichloroethylene and 12 other components is toxic for porcine embryos (at relative concentrations of 1-10000-fold the environmental organochlorine levels of contamination or 4.2 microg/l total PCBs). We also tested the embryotoxicity of a metabolised organochlorine mixture (relative concentrations of 0.9, 1.8, 2.7, 3.6 and 4.5 microg/l hydroxy-PCBs (OH-PCBs)) obtained by extracting plasma samples from sows treated with the native mixture. Embryos produced in vitro were exposed to either the organochlorine mixture or the metabolised extract for 9 days. The organochlorine mixture reduced embryonic development at the 10000x concentration (relative concentration of 42 mg/l PCBs; p=0.05). The organochlorine mixture also reduced the mean number of blastomeres per expanded blastocyst in a dose-dependent manner (p=0.038) but did not induce blastomere apoptosis (p>0.05). In contrast, the metabolised extract did not affect development or blastomere number at the concentrations tested, although the highest level of this mixture (4.5 microg/l OH-PCBs) was still very low (i.e. similar to the 1x concentration of the organochlorine mixture, which also did not alter embryo parameters). These data lead to the conclusion that while high concentrations of the native organochlorine mixture are toxic for porcine embryos, concentrations of either the native or the metabolised mixture that bear some relevance to exposure of human populations in the Arctic were without observable effect.

Women exposure during pregnancy to haloacetaldehydes and haloacetonitriles in drinking water and risk of small-for-gestational-age neonate

BACKGROUND Past studies have examined the effects of maternal exposure to water chlorination disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs) during pregnancy. However, no human-based study has yet evaluated the effect of emerging DBPs, such as haloacetaldehydes (HAs) and haloacetonitriles (HANs) on small-for-gestational-age (SGA) status in newborns. OBJECTIVE This study aims to assess the association between maternal multiroute exposure to HAs and HANs during the third trimester of pregnancy and SGA status at birth, among neonates delivered by women residing in the Quebec City area (Province of Quebec, Canada). We also evaluated the interaction between exposure to these emerging unregulated by-products and regulated DBPs also found in drinking water (THMs and HAAs), for which a positive association with adverse reproductive outcomes has been suggested in previous studies. METHODS We conducted a population-based case-control study in the Quebec City area. SGA newborns (n=330) were compared to 1100 controls, with matching based on calendar week of birth. HA and HAN concentrations in drinking water at participants tap were estimated using spatio-temporal strategy based on bimonthly measurements carried out at several locations in the participants distribution system. A computer-assisted telephone interview was completed to collect information on individual habits of water consumption and water related activities in order to determine individual multiroute exposure. This enabled us to estimate the dose of HAs and HANs absorbed daily by each participant. Associations between total HA, HAN concentrations in drinking water and SGA were analyzed. Associations between the daily-absorbed doses of these emerging DBPs and SGA were also analyzed. Odds ratios (ORs) comparing the 4th quartile of exposure to the reference group (the first three quartiles) were obtained by means of conditional logistic regression, and controlling for potential confounders. RESULTS Globally, no evidence of increased risk of SGA was found with total HA and HAN concentrations in tap water when participants in the 4th quartile of exposure were compared to the first three quartiles (OR=1.0; 95% CI [0.7-1.5] and OR=0.8; 95% CI [0.6-1.2], respectively). Similarly, no association was found with the daily-absorbed doses of total HAs or HANs (OR=0.9; 95% CI [0.6-1.3] and OR=1.1; 95% CI [0.7-1.6], respectively). However, a small non statistically significant association was found between the dose of brominated HA and SGA (OR=1.4; 95% CI [0.9-2.1]). Also, in spite of the lack of interaction between other DBP classes, an unexpected negative interaction was observed between concentration of chloral hydrate (CH) (which represents the main HA species), and regulated DBPs (P=0.006). CONCLUSION In this population, exposure to low levels of HAs and HANs during the third trimester of pregnancy through drinking water was not associated to SGA status in newborns. Nonetheless, more research is needed to clarify possible effect of brominated compounds and interaction between different DBPs.

Disinfection by-products exposure and intra-uterine growth restriction: Do genetic polymorphisms of CYP2E1or deletion of GSTM1 or GSTT1 modify the association?

BACKGROUND Exposure to disinfection by-products (DBPs) during pregnancy was associated with reduced foetal growth. Genetic susceptibility might play a role, especially for genes encoding for the Cytochrome P450 (CYP2E1) and Glutathione S-Transferase (GST) enzymes, involved in metabolism and activation of DBPs. Few epidemiological studies evaluated these gene-environment interactions and their results were never replicated. OBJECTIVE This study aims to examine interactions between trihalomethanes (THM) or haloacetic acids (HAA) exposure and genetic polymorphisms on small for gestational age (SGA) neonates by investigating single nucleotide polymorphisms (SNPs) in CYP2E1 gene and GSTM1 and GSTT1 deletions in mothers-children pairs. METHODS A population-based case-control study of 1549 mothers and 1455 children was conducted on SGA and THM/HAA exposure. DNA was extracted from blood or saliva cells. Targeted SNPs and deletions were genotyped. Statistical interaction between SNPs/deletions and THMs or HAAs in utero exposure with regard to SGA occurrence was evaluated by unconditional logistic regression with control of potential confounders. RESULTS Previously reported positive modification of the effect of THM uterine exposure by mothers or newborns CYP2E1 rs3813867 C allele or GSTM1 deletion was not replicated. However interactions with CYP2E1 rs117618383 and rs2515641 were observed but were not statistically significant after correction for multiple testing. CONCLUSIONS Previous positive interactions between THMs exposure and CYP2E1 and GSTM1 were not replicated but interactions with other CYP2E1 polymorphisms are reported.

Mechanisms involved in porcine early embryo survival following ethanol exposure

Alcohol consumption during pregnancy is still a cause of preventable birth defects and developmental disabilities. However, little is known about the impact of ethanol on preimplantation embryos and the molecular mechanisms involved. We aimed to determine the toxicogenomic impacts and the mechanisms involved in preimplantation embryonic survival following 0.2% ethanol exposure in porcine embryos. Gene expression changes were measured with a porcine embryo specific microarray and confirmed by RT-qPCR. When compared with control, ethanol exposure led to a 43% decrease in blastocyst rate and activated pathways associated with oxidative stress and nervous system damage, such as TP53 and TGF. Moreover, we observed a mitochondrial dysfunction in the exposed embryos as revealed by the decrease in Mitotracker Red fluorescence intensity (25 and 41% in 4-cell embryos and blastocysts, respectively) and a modification in the expression of GABRB3, APP, CLU, and MIOX genes. We therefore present evidence of neuronal-like adverse effects on undifferentiated cells suggesting that fetal alcohol spectrum disorder could have its origin as early as in the first week postfertilization.

Integrated Management of Residential Indoor Air Quality: A Call for Stakeholders in a Changing Climate

A paradigm change in the management of environmental health issues has been observed in recent years: instead of managing specific risks individually, a holistic vision of environmental problems would assure sustainable solutions. However, concrete actions that could help translate these recommendations into interventions are lacking. This review presents the relevance of using an integrated indoor air quality management approach to ensure occupant health and comfort. At the nexus of three basic concepts (reducing contaminants at the source, improving ventilation, and, when relevant, purifying the indoor air), this approach can help maintain and improve indoor air quality and limit exposure to several contaminants. Its application is particularly relevant in a climate change context since the evolving outdoor conditions have to be taken into account during building construction and renovation. The measures presented through this approach target public health players, building managers, owners, occupants, and professionals involved in building design, construction, renovation, and maintenance. The findings of this review will help the various stakeholders initiate a strategic reflection on the importance of indoor air quality and climate change issues for existing and future buildings. Several new avenues and recommendations are presented to set the path for future research activities.