Increases in Serum Nitrite and Nitrate of a Few-Fold Adversely Affect the Outcome of Pregnancy in Rats

Maternal exposure to ambient air pollution and congenital heart defects in China

BACKGROUND

Evidence of maternal exposure to ambient air pollution on congenital heart defects (CHD) has been mixed and are still relatively limited in developing countries. We aimed to investigate the association between maternal exposure to air pollution and CHD in China.

METHOD

This longitudinal, population-based, case-control study consecutively recruited fetuses with CHD and healthy volunteers from 21 cities, Southern China, between January 2006 and December 2016. Residential address at delivery was linked to random forests models to estimate maternal exposure to particulate matter with an aerodynamic diameter of ≤ 1 µm (PM₁), ≤2.5 µm, and ≤10 µm as well as nitrogen dioxides, in three trimesters. The CHD cases were evaluated by obstetrician, pediatrician, or cardiologist, and confirmed by cardia ultrasound. The CHD subtypes were coded using the International Classification Diseases. Adjusted logistic regression models were used to assess the associations between air pollutants and CHD and its subtypes.

RESULTS

A total of 7055 isolated CHD and 6423 controls were included in the current analysis. Maternal air pollution exposures were consistently higher among cases than those among controls. Logistic regression analyses showed that maternal exposure to all air pollutants during the first trimester was associated with an increased odds of CHD (e.g., an interquartile range [13.3 µg/m³] increase in PM₁ was associated with 1.09-fold ([95% confidence interval, 1.01-1.18]) greater odds of CHD). No significant associations were observed for maternal air pollution exposures during the second trimester and the third trimester. The pattern of the associations between air pollutants and different CHD subtypes was mixed.

CONCLUSIONS

Maternal exposure to greater levels of air pollutants during the pregnancy, especially the first trimester, is associated with higher odds of CHD in offspring. Further longitudinal well-designed studies are warranted to confirm our findings.

Prenatal exposure to PM2.5 and Congenital Heart Diseases in Taiwan

Gestational exposure to ambient air pollution has been associated with Congenital Heart Diseases (CHDs). However, only a few studies, with inconsistent results, have investigated the effects of PM_2.5 exposure during early pregnancy. This study aims to evaluate the association between prenatal exposure to PM_2.5 and CHDs occurrence. We selected 782 births reported to have CHDs between 2007 and 2014 from the Taiwanese Birth Registry and randomly selected 4692 controls without any birth defects using a population-based case-control design. Data of exposure to ambient air pollutants, mainly PM_2.5, PM₁₀, CO, SO₂, NO₂, and O₃ during weeks 3-8 of pregnancy were retrieved from air quality monitoring stations and interpolated to every township using ordinary kriging. We applied unconditional logistic regression models adjusted for potential confounders to evaluate the associations. The results revealed a positive correlation between increased PM_2.5 exposure (adjusted odds ratio [aOR] = 1.21, 95% confidence interval [CI] = 1.03-1.42, per interquartile range change = 13.4 μg/m³) during early pregnancy and overall CHDs occurrence. Furthermore, we found that atrial septal defect (aOR = 1.43, 95% CI = 1.01-2.02), endocardial cushion defect (aOR = 2.37, 95% CI = 1.01-5.58), and pulmonary artery and valve stenosis (aOR = 1.71, 95% CI = 1.06-2.78) were significantly associated with PM_2.5 exposures. No similar effects were observed for the other air pollutants. This study has demonstrated some positive associations between increased PM_2.5 exposure during the critical period of cardiac embryogenesis and certain CHDs occurrence.

Retrospective study of cattle poisonings in California: recognition, diagnosis, and treatment

In this retrospective study all suspect bovine intoxications submitted to the California Animal Health and Food Safety Laboratory between January 1, 2000 and December 31, 2011 were reviewed. A total of 1199 cases were submitted, but a diagnosis of intoxication was only established in 13.5% of cases. In these cases, overexposures to minerals, metals, and poisonous plants were determined as the most commonly diagnosed poisonings in cattle in California. Nitrate/nitrite poisoning was the most commonly diagnosed plant-associated intoxication, followed by gossypol and oleander. This study details the diagnostic challenges and treatment options for the most commonly diagnosed intoxications. To ensure proper treatment and prevention of new cases, accurate diagnosis is necessary, and therefore this review provides an essential tool for the food animal practitioner. Available toxicological analyses are offered at select laboratories, which can be time consuming and expensive, yet the potential for residues in consumed animal products and implications for human health necessitate testing and consultation. Any potential exposure to a toxicant in cattle should be reviewed to determine whether a residue hazard exists. Therapy focuses on immediate removal of the toxicant from the environment and from the gastrointestinal tract. With few antidotes available, most are cost prohibitive to treat numerous affected cattle. In addition, most antidotes will require extra-label drug use and establishment of meat and milk withdrawal times.

Developmental toxicity of glyceryl trinitrate in quail embryos

BACKGROUND

Although glyceryl trinitrate (GTN) is used extensively to treat angina and heart failure, little is known about its effects on the conceptus during organogenesis. The goal of these studies was to investigate the effects of GTN in a model organism, the quail (Coturnix coturnix japonica) embryo.

METHODS

To identify the effects of GTN on quail embryo development, fertilized quail eggs (n = 10-12 eggs/group) were injected with GTN (0, 4.4, 44, or 440 μM) at Hamburger-Hamilton (HH) stage 0, 9, or 19 and examined 7 days later. Next, HH 9 embryos were injected with GTN (0, 0.88, 4.4, 8.8, 44, 88, and 440 μM, in 20 μL per egg) and examined 24-hours, 48-hours, or 72-hours postinjection. Finally, the developing eye on one side was exposed to GTN (44 μM) ex ovo and the tissue was probed for the presence of nitrated proteins.

RESULTS

In ovo GTN exposure induced a dose-dependent increase in the number of malformed viable quail embryos with a maximal effect in HH 9 embryos. Microphthalmia, craniofacial, heart, and neural tube defects were elevated in GTN-exposed embryos. An increase in nitrated proteins was observed in the developing eye region of embryos exposed ex ovo to GTN.

CONCLUSIONS

GTN treatment induced a variety of malformations in quail embryos. The presence of nitrated proteins suggests that organic nitrates, such as GTN, generate reactive nitrogen species. We hypothesize that GTN perturbations in the redox status of the embryo may underlie its developmental toxicity.

Ambient air pollution and congenital heart disease: a register-based study

Maternal exposure to ambient air pollution has increasingly been linked to adverse pregnancy outcomes. The evidence linking this exposure to congenital anomalies is still limited and controversial. This case-control study investigated the association between maternal exposure to ambient particulate matter with aerodynamic diameter less than 10 μm (PM(10)), sulfur dioxide (SO(2)), nitrogen dioxide, nitric oxide (NO), ozone (O(3)), and carbon monoxide (CO) and the occurrence of congenital heart disease in the population of Northeast England (1993-2003). Each case and control was assigned weekly average (weeks 3-8 of pregnancy) of pollutant levels measured by the closest monitor to the mother's residential postcode. Using exposure as both continuous and categorical variables, logistic regression models were constructed to quantify the adjusted odds ratios of exposure to air pollutants and the occurrence of each outcome group. We found exposure to CO and NO to be associated with ventricular septal defect and cardiac septa malformations. CO was also associated with congenital pulmonary valve stenosis and NO with pooled cases of congenital heart disease and tetralogy of Fallot. Findings for SO(2), O(3) and PM(10) were less consistent.

Association between maternal exposure to ambient air pollution and congenital heart disease: A register-based spatiotemporal analysis

Recent studies have linked maternal exposure to air pollution with a range of adverse pregnancy outcomes. However, the available evidence linking this exposure to congenital anomalies is still limited and controversial. The present case-control study tested the hypothesis that maternal exposure to ambient black smoke and sulfur dioxide is a risk factor for the occurrence of congenital heart disease. The authors used registry-based data on congenital heart disease for the population of the northeast of England in 1985-1996. A 2-stage spatiotemporal model was developed to predict weekly black smoke and sulfur dioxide levels at each maternal place of residence. Controls were frequency-matched to cases by year of birth (control-to-case ratio of 4:1). Two sets of analyses were performed, using predicted mean values of exposure and 1,000 simulated scenarios of exposure. The analyses were adjusted for birth year, socioeconomic status, infant sex, season of conception, and degree of urbanity. The authors found a weak association between maternal exposure to black smoke and congenital malformations of cardiac chambers and connections only when using exposure as a continuous variable. When the authors used quartiles of exposure, odds ratios did not show a dose-response relation for consecutive quartiles. For sulfur dioxide, the results were not indicative of any association.

Effects of environmental pollutants on the reproduction and welfare of ruminants

Anthropogenic pollutants comprise a wide range of synthetic organic compounds and heavy metals, which are dispersed throughout the environment, usually at low concentrations. Exposure of ruminants, as for all other animals, is unavoidable and while the levels of exposure to most chemicals are usually too low to induce any physiological effects, combinations of pollutants can act additively or synergistically to perturb multiple physiological systems at all ages but particularly in the developing foetus. In sheep, organs affected by pollutant exposure include the ovary, testis, hypothalamus and pituitary gland and bone. Reported effects of exposure include changes in organ weight and gross structure, histology and gene and protein expression but these changes are not reflected in changes in reproductive performance under the conditions tested. These results illustrate the complexity of the effects of endocrine disrupting compounds on the reproductive axis, which make it difficult to extrapolate between, or even within, species. Effects of pollutant exposure on the thyroid gland, immune, cardiovascular and obesogenic systems have not been shown explicitly, in ruminants, but work on other species suggests that these systems can also be perturbed. It is concluded that exposure to a mixture of anthropogenic pollutants has significant effects on a wide variety of physiological systems, including the reproductive system. Although this physiological insult has not yet been shown to lead to a reduction in ruminant gross performance, there are already reports indicating that anthropogenic pollutant exposure can compromise several physiological systems and may pose a significant threat to both reproductive performance and welfare in the longer term. At present, many potential mechanisms of action for individual chemicals have been identified but knowledge of factors affecting the rate of tissue exposure and of the effects of combinations of chemicals on physiological systems is poor. Nevertheless, both are vital for the identification of risks to animal productivity and welfare.

Analysis of nitrate ion in nettle (Urtica dioica L.) by ion-pair chromatographic method on a C30 stationary phase

Nitrate ion is a frequent pollutant not only in soil and natural water resources but in vegetables and foods as well. In our study we focused on nettle due to its increased ability to accumulate nitrate ions. A new, simple method for the separation and determination of nitrate ion based on reversed-phase ion-pair chromatography has been elaborated. A new four-step sample pretreatment method enables the precipitation of proteins and oxidative degradation of compounds that may disturb the identification of the nitrate ion: (1) extraction of the total nitrate content, (2) precipitation of proteins with acetonitrile, (3) oxidative degradation of the organic contaminants with H2O2, (4) evaporation of the solvent and taking up of the residue in water. The chromatographic separations were carried out on a high-density C30 stationary phase under isocratic conditions. The optimal mobile-phase composition was 10% (v/v) acetonitrile and 90% (v/v) 20 mmol L(-1) phosphate buffer, containing 2 mmol of tetrabutylammonium hydroxide at pH 6.0. The method could also be used for the separation of IO3(-), SeO3(2-), BrO3(-), NO2(-), Br-, SeO4(2-), and I- ions. The validated method is sensitive (the detection limit is 0.18 ng of nitrate ion). The method is linear in a high concentration range (0.031-30.66 microg mL(-1)). Recoveries varied between 98% and 103%. Reproducibility of the elaborated sample pretreatment method showed 1.54%. The method can be used for the determination of nitrate ion from different plants.