Maternal exposure to airborne particulate matter causes postnatal immunological dysfunction in mice offspring

Before the first breath: why ambient air pollution and climate change should matter to neonatal-perinatal providers

Common outdoor air pollutants present threats to fetal and neonatal health, placing neonatal-perinatal clinical specialists in an important role for harm reduction through patient counseling and advocacy. Climate change is intertwined with air pollution and influences air quality. There is increasing evidence demonstrating the unique vulnerability in the development of adverse health consequences from exposures during the preconception, prenatal, and early postnatal periods, as well as promising indications that policies aimed at addressing these toxicants have improved birth outcomes. Advocacy by neonatal-perinatal providers articulating the potential impact of pollutants on newborns and mothers is essential to promoting improvements in air quality and reducing exposures. The goal of this review is to update neonatal-perinatal clinical specialists on the key ambient air pollutants of concern, their sources and health effects, and to outline strategies for protecting patients and communities from documented adverse health consequences.

Wildfire Smoke Exposure during Pregnancy: A Review of Potential Mechanisms of Placental Toxicity, Impact on Obstetric Outcomes, and Strategies to Reduce Exposure

Climate change is accelerating the intensity and frequency of wildfires globally. Understanding how wildfire smoke (WS) may lead to adverse pregnancy outcomes and alterations in placental function via biological mechanisms is critical to mitigate the harms of exposure. We aim to review the literature surrounding WS, placental biology, biological mechanisms underlying adverse pregnancy outcomes as well as interventions and strategies to avoid WS exposure in pregnancy. This review includes epidemiologic and experimental laboratory-based studies of WS, air pollution, particulate matter (PM), and other chemicals related to combustion in relation to obstetric outcomes and placental biology. We summarized the available clinical, animal, and placental studies with WS and other combustion products such as tobacco, diesel, and wood smoke. Additionally, we reviewed current recommendations for prevention of WS exposure. We found that there is limited data specific to WS; however, studies on air pollution and other combustion sources suggest a link to inflammation, oxidative stress, endocrine disruption, DNA damage, telomere shortening, epigenetic changes, as well as metabolic, vascular, and endothelial dysregulation in the maternal-fetal unit. These alterations in placental biology contribute to adverse obstetric outcomes that disproportionally affect the most vulnerable. Limiting time outdoors, wearing N95 respirator face masks and using high quality indoor air filters during wildfire events reduces exposure to related environmental exposures and may mitigate morbidities attributable to WS.

Early life exposure to air pollution and cell-mediated immune responses in preschoolers

BACKGROUND

Exposure to air pollution has been linked with altered immune function in adults, but little is known about its effects on early life. This study aimed to investigate the effects of exposure to air pollution during prenatal and postnatal windows on cell-mediated immune function in preschoolers.

METHODS

Pre-school aged children (2.9 ± 0.5 y old, n = 391) were recruited from a mother-child cohort study in Wuhan, China. We used a spatial-temporal land use regression (LUR) model to estimate exposures of particulate matter with aerodynamic diameters ≤2.5 μm (PM_2.5) and ≤10 μm (PM₁₀), and nitrogen dioxide (NO₂) during the specific trimesters of pregnancy and the first two postnatal years. We measured peripheral blood T lymphocyte subsets and plasma cytokines as indicators of cellular immune function. We used multiple informant models to examine the associations of prenatal and postnatal exposures to air pollution with cell-mediated immune function.

RESULTS

Prenatal exposures to PM_2.5, PM₁₀, and NO₂ during early pregnancy were negatively associated with %CD3⁺ and %CD3⁺CD8⁺ cells, and during late pregnancy were positively associated with %CD3⁺ cells. Postnatal exposures to these air pollutants during 1-y or 2-y childhood were positively associated with IL-4, IL-5, IL-6, and TNF-α. We also observed that the associations of prenatal or postnatal air pollution exposures with cellular immune responses varied by child's sex.

CONCLUSIONS

Our results suggest that exposure to air pollution during different critical windows of early life may differentially alter cellular immune responses, and these effects appear to be sex-specific.

Prenatal and Postnatal Household Air Pollution Exposures and Pneumonia Risk: Evidence From the Ghana Randomized Air Pollution and Health Study

BACKGROUND

Nearly 40% of the world's population is exposed daily to household air pollution. The relative impact of prenatal and postnatal household air pollution exposure on early childhood pneumonia, a leading cause of mortality, is unknown.

RESEARCH QUESTION

Are prenatal or postnatal household air pollution, or both, associated with pneumonia risk in the first year of life?

STUDY DESIGN AND METHODS

The Ghana Randomized Air Pollution and Health Study enrolled 1,414 nonsmoking, pregnant women before 24 weeks' gestation with prospective follow-up to the child's age of 1 year. We measured 72-h personal household air pollution exposures, indexed by carbon monoxide (CO), four times prenatally and three times postnatally. Weekly fieldworker surveillance identified ill-appearing children for physician pneumonia assessment. We used quasi-Poisson models to examine associations between prenatal and postnatal CO and physician-diagnosed pneumonia and severe pneumonia. Sex-specific effects were examined.

RESULTS

Of the 1,306 live births, 1,141 infants were followed up with 55,605 child-weeks of fieldworker surveillance. The estimated risk for pneumonia and severe pneumonia in the first year of life increased by 10% (relative risk [RR], 1.10; 95% CI, 1.04-1.16) and 15% (RR, 1.15; 95% CI, 1.03-1.28), respectively, per 1-part per million (ppm) increase in average prenatal CO exposure and by 6% (RR, 1.06; 95% CI, 0.99-1.13) per 1-ppm increase in average postnatal CO exposure. Sex-stratified analyses suggest that in girls, higher prenatal CO exposure was associated with pneumonia risk, while no association was seen in boys.

INTERPRETATION

Prenatal household air pollution exposure increased risk of pneumonia and severe pneumonia in the first year of life. Clean-burning interventions may be most effective when begun prenatally.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01335490; URL: www.clinicaltrials.gov.

Role of air pollution in chronic kidney disease: an update on evidence, mechanisms and mitigation strategies

Air pollution results from a variable and complex mixture of harmful gases and suspended particles and is the most worrisome of all environmental hazards. It is implicated in several non -communicable diseases and is recognized to be a public health problem. Though the initial exposure to air pollution is through the respiratory system, kidneys are thought to be exposed to higher concentrations owing to their filtration function. Chronic kidney disease is the insidious end result of several disease processes which cumulatively form a large healthcare burden, particularly in low- and middle-income countries. There is a growing body of evidence that air pollution may be a contributing factor that leads to CKD by not only its direct effects, but can also compound the effect of other factors/diseases causing kidney injury. PM_2.5 exposure particularly has been implicated, although there is some evidence regarding other air pollutants as well. These pollutants are thought to act on kidneys through several interlinked systemic pathways and mechanisms which individually and collectively damage the nephrons. Long-term exposures seem to gradually diminish renal function and lead to end-stage renal disease. A thorough understanding of the mechanism of kidney injury is the key for formulating and implementing effective strategies for reducing this burden. Maintaining the air quality, promoting education, improving health quality and promotion of targeted nephroprotective measures through effective policy and research support are required in addressing this global public health problem.

Air pollution and children's health-a review of adverse effects associated with prenatal exposure from fine to ultrafine particulate matter

BACKGROUND

Particulate matter (PM), a major component of ambient air pollution, accounts for a substantial burden of diseases and fatality worldwide. Maternal exposure to PM during pregnancy is particularly harmful to children's health since this is a phase of rapid human growth and development.

METHOD

In this review, we synthesize the scientific evidence on adverse health outcomes in children following prenatal exposure to the smallest toxic components, fine (PM_2.5) and ultrafine (PM_0.1) PM. We highlight the established and emerging findings from epidemiologic studies and experimental models.

RESULTS

Maternal exposure to fine and ultrafine PM directly and indirectly yields numerous adverse birth outcomes and impacts on children's respiratory systems, immune status, brain development, and cardiometabolic health. The biological mechanisms underlying adverse effects include direct placental translocation of ultrafine particles, placental and systemic maternal oxidative stress and inflammation elicited by both fine and ultrafine PM, epigenetic changes, and potential endocrine effects that influence long-term health.

CONCLUSION

Policies to reduce maternal exposure and health consequences in children should be a high priority. PM_2.5 levels are regulated, yet it is recognized that minority and low socioeconomic status groups experience disproportionate exposures. Moreover, PM_0.1 levels are not routinely measured or currently regulated. Consequently, preventive strategies that inform neighborhood/regional planning and clinical/nutritional recommendations are needed to mitigate maternal exposure and ultimately protect children's health.

Emerging role of mitochondria in airborne particulate matter-induced immunotoxicity

The immune system is one of the primary targets of airborne particulate matter. Recent evidence suggests that mitochondria lie at the center of particulate matter-induced immunotoxicity. Particulate matter can directly interact with mitochondrial components (proteins, lipids, and nucleic acids) and impairs the vital mitochondrial processes including redox mechanisms, fusion-fission, autophagy, and metabolic pathways. These disturbances impede different mitochondrial functions including ATP production, which acts as an important platform to regulate immunity and inflammatory responses. Moreover, the mitochondrial DNA released into the cytosol or in the extracellular milieu acts as a danger-associated molecular pattern and triggers the signaling pathways, involving cGAS-STING, TLR9, and NLRP3. In the present review, we discuss the emerging role of mitochondria in airborne particulate matter-induced immunotoxicity and its myriad biological consequences in health and disease.

Consequences of maternal psychological stress during pregnancy for the risk of asthma in the offspring

Asthma is a common lung condition that makes breathing difficult through the inflammation and constriction of the lung airways. Epidemiological evidence supports the presence of a positive association between prenatal maternal psychological stress (PMPS) and asthma in the offspring, suggesting the disease may have developmental origins. T-helper 2 (Th2) cells are a major subtype of T-helper cells, producing Th2 cytokines, which may be the main drivers of asthma symptoms. A Th2 dominant blood cytokine profile may therefore indicate an increased risk of asthma, as studies have shown a link between PMPS and a T-helper 2 (Th2) cytokine profile in offspring. The mechanism by which PMPS may cause Th2 cytokine dominance in the offspring is unclear. Epigenetic modifications in utero can lead to long-lasting effects that persist postnatally and have therefore been implicated in this relationship. Increased maternal blood cortisol levels due to PMPS may increase transfer of cortisol to the foetus, where the temporarily increased levels may induce changes in the epigenome. Evidence from animal studies suggests that genes controlling cytokine production in T cells can be epigenetically modified in a way that increases Th2 cytokine production. Other evidence suggests that methylation of the NR3C1 gene decreases hippocampal glucocorticoid receptor expression, leading to decreased negative regulation of the hypothalamus-pituitary-adrenal axis. This can increase cortisol production which has been shown to increase Th2 cytokine production. Therefore, the link between PMPS and a Th2 offspring cytokine profile, mediated through epigenetic changes, may explain the positive relationship between PMPS and asthma in the offspring.

Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the US: A Systematic Review

IMPORTANCE

Knowledge of whether serious adverse pregnancy outcomes are associated with increasingly widespread effects of climate change in the US would be crucial for the obstetrical medical community and for women and families across the country.

OBJECTIVE

To investigate prenatal exposure to fine particulate matter (PM2.5), ozone, and heat, and the association of these factors with preterm birth, low birth weight, and stillbirth.

EVIDENCE REVIEW

This systematic review involved a comprehensive search for primary literature in Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, PubMed, ClinicalTrials.gov website, and MEDLINE. Qualifying primary research studies included human participants in US populations that were published in English between January 1, 2007, and April 30, 2019. Included articles analyzed the associations between air pollutants or heat and obstetrical outcomes. Comparative observational cohort studies and cross-sectional studies with comparators were included, without minimum sample size. Additional articles found through reference review were also considered. Articles analyzing other obstetrical outcomes, non-US populations, and reviews were excluded. Two reviewers independently determined study eligibility. The Arskey and O'Malley scoping review framework was used. Data extraction was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

FINDINGS

Of the 1851 articles identified, 68 met the inclusion criteria. Overall, 32 798 152 births were analyzed, with a mean (SD) of 565 485 (783 278) births per study. A total of 57 studies (48 of 58 [84%] on air pollutants; 9 of 10 [90%] on heat) showed a significant association of air pollutant and heat exposure with birth outcomes. Positive associations were found across all US geographic regions. Exposure to PM2.5 or ozone was associated with increased risk of preterm birth in 19 of 24 studies (79%) and low birth weight in 25 of 29 studies (86%). The subpopulations at highest risk were persons with asthma and minority groups, especially black mothers. Accurate comparisons of risk were limited by differences in study design, exposure measurement, population demographics, and seasonality.

CONCLUSIONS AND RELEVANCE

This review suggests that increasingly common environmental exposures exacerbated by climate change are significantly associated with serious adverse pregnancy outcomes across the US.

Environmental exposures during pregnancy: Mechanistic effects on immunity

In human studies, it is well established that exposures during embryonic and fetal development periods can influence immune health. Coupled with genetic predisposition, these exposures can alter lifetime chronic and infectious disease trajectory, and, ultimately, life expectancy. Fortunately, as research advances, mechanisms governing long-term effects of prenatal exposures are coming to light and providing the opportunity for intervention and risk reduction. For instance, human association studies have provided a foundation for the association of prenatal exposure to particulate matter with early immunosuppression and later allergic disease in the offspring. Only recently, the mechanisms mediating this response have been revealed and there is much we have yet to discover. Although cellular immune response is understood for many exposure scenarios, molecular pathways are still unidentified. This review will provide commentary and synthesis of the current literature regarding environmental exposures during pregnancy and mechanisms determining immune outcomes. Shared mechanistic features and current gaps in the state of the science are identified and discussed. To such purpose, we address exposures by their immune effect type: immunosuppression, autoimmunity, inflammation and tissue damage, hypersensitivity, and general immunomodulation.

Varied dose exposures to ultrafine particles in the motorcycle smoke cause kidney cell damages in male mice

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Exposure to ultrafine particles has significant effect on kidney cell deformation.

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The exposure results in alterations in glomerular and tubular epithelial cells.

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Ultrafine particle concentration determines kidney cell deformation.

Ultrafine particles (UFPs) are one of motorcycle exhaust emissions which can penetrate the lung alveoli and deposit in the kidney. This study was aimed to investigate mice kidney cell physical damage (deformation) due to motorcycle exhaust emission exposures. The motorcycle exhaust emissions were sucked from the muffler with the rate of 33 cm³/s and passed through an ultrafine particle filter system before introduced into the mice exposure chamber. The dose concentration of the exhaust emissions was varied by setting the injected time of the 20s, 40s, 60s, 80s, and 100s. The mice were exposed to the smoke in the chamber for 100 s twice a day. The impact of the ultrafine particles on the kidney was observed by identifying the histological image of the kidney cell deformation using a microscope. The exposure was conducted for 10 days. The kidney observations were carried out on day 11. The results showed that there was a significant linear correlation between the total concentration of ultrafine particles deposited in the kidneys and the physical damage percentages. The increased concentrations of ultrafine particles caused larger cell deformation to the kidneys.

Cause-specific stillbirth and exposure to chemical constituents and sources of fine particulate matter

The stillbirth rate in the United States is relatively high, but limited evidence is available linking stillbirth with fine particulate matter (PM_2.5), its chemical constituents and sources. In this study, we explored associations between cause-specific stillbirth and prenatal exposures to those pollutants with using live birth and stillbirth records from eight California locations during 2002-2009. ICD-10 codes were used to identify cause of stillbirth from stillbirth records. PM_2.5 total mass and chemical constituents were collected from ambient monitors and PM_2.5 sources were quantified using Positive Matrix Factorization. Conditional logistic regression was applied using a nested case-control study design (N = 32,262). We found that different causes of stillbirth were associated with different PM_2.5 sources and/or chemical constituents. For stillbirths due to fetal growth, the odds ratio (OR) per interquartile range increase in gestational age-adjusted exposure to PM_2.5 total mass was 1.23 (95% confidence interval (CI): 1.06, 1.44). Similar associations were found with resuspended soil (OR=1.25, 95% CI: 1.10, 1.42), and secondary ammonium sulfate (OR=1.45, 95% CI: 1.18, 1.78). No associations were found between any pollutants and stillbirths caused by maternal complications. This study highlighted the importance of investigating cause-specific stillbirth and the differential toxicity levels of specific PM_2.5 sources and chemical constituents.

Developmental fluoride exposure influenced rat's splenic development and cell cycle via disruption of the ERK signal pathway

Excessive fluoride exposure has been reported to cause damage to spleen. Neonatal period is characterized by rapid proliferation and differentiation of lymphocyte in the spleen. Children may be more sensitive to the toxicity of fluoride compared to the adults. The aim of this study was to investigate the effects of postnatal exposure (from neonatal period to early adulthood) to fluoride on the development of spleen on a regular basis and the underlying signal pathway. Results showed a marked decrease in spleen weight index and altered morphology in the spleen of fluoride-treated group on PND-84, which reflected fluoride inhibition of the development of spleen. Fluoride exposure induced cell cycle arrest of splenocytes and decreased the mRNA expression of IL-2, which indicated compromised baseline lymphocyte proliferation in the spleen. Time course research from 3-wk-of-age until 12-wk-of-age showed an adverse and cumulative impact of fluoride on the development of spleen. In view of the key role of MAPK/ERK pathway in lymphocyte development, Raf-1/MEK-1/ERK-2/c-fos mRNA expression and ERK/p-ERK protein expression were detected. Results showed despite a transitory increase in mRNA expression from PND-42 to PND-63 in fluoride-treated group, the expression of these genes on PND-84 decreased significantly compared with PND-42 or PND-63. NaF significantly inhibited the phosphorylation of ERK protein on PND-84. Taken together, these results emphasized the vital role of ERK pathway in the interfered development of spleen induced by a high dose of fluoride exposure in rats.

Maternal Glucocorticoid Elevation and Associated Fetal Thymocyte Apoptosis are Involved in Immune Disorders of Prenatal Caffeine Exposed Offspring Mice

Our previous study showed that prenatal caffeine exposure (PCE) could induce intrauterine growth retardation (IUGR) and glucocorticoid elevation in the fetus. Researchers suggested that IUGR is a risk factor for T helper cell (Th)1/Th2 deviation. However, whether PCE can induce these immune disorders and the underlying mechanisms of that induction remain unknown. This study aimed to observe the effects of PCE on the Th1/Th2 balance in offspring and further explore the developmental origin mechanisms from the perspective of glucocorticoid overexposure-induced thymocyte apoptosis. An IUGR model was established by caffeine administration from gestational day (GD) 9 to GD 18, and the offspring were immunized on postnatal day (PND) 42. The results show that maternal glucocorticoid overexposure increased fetal thymocyte apoptosis by activating both the Fas-mediated and the Bim-regulated apoptotic pathways. After birth, accelerated thymocyte apoptosis and Th1 suppression were also found in the PCE offspring at PND 14 and PND 49. Moreover, the PCE offspring showed immune disorders after immunization, manifesting as increased IgG1/IgG2a ratio and IL-4 production in the serum. In conclusion, PCE could induce fetal overexposure to maternal glucocorticoids and increase thymocyte apoptosis, which could persist into postnatal life and be implicated in Th1 inhibition and further immune disorders.

Maternal exposure to ambient PM2.5 exaggerates fetal cardiovascular maldevelopment induced by homocysteine in rats

Maternal exposure to airborne particulate matter with aerodynamic diameter <2.5 µm (PM_2.5 ) during pregnancy and lactation periods is associated with filial congenital cardiovascular diseases. This study aimed to investigate the toxic effects of maternal exposure to ambient levels of PM_2.5 on filial cardiovascular maldevelopment induced by homocysteine. Using a 2 × 2 factorial design, rats were randomized into four groups and were exposed to ambient PM_2.5 or filtered air (FA) throughout the pregnancy and lactation periods coupled with the administration of either homocysteine (HCY) or normal saline (NS) daily from gestation days 8-10. Morphological changes in the heart, myocardial apoptosis, expressions of cardiac progenitor transcriptional factors, and levels of cytokines were investigated in the offspring. The apoptosis-like changes in the myocardium were seen in the FA plus HCY-treated group and more obviously in the PM_2.5 plus HCY-treated group, which was in accordance with an increased myocardial apoptosis rate in the two groups. PM_2.5 exposure resulted in significantly decreased Nkx2-5 protein level and GATA4 and Nkx2-5 mRNA expressions, and significantly increased TNF-α and IL-1β levels. There were significant interactions between PM_2.5 exposure and HCY-treatment that PM_2.5 exposure reduced Nkx2-5 protein levels and GATA4 and Nkx2-5 mRNA expressions in the HCY-treated groups. These results suggest that maternal exposure to PM_2.5 , even at the ambient levels in urban regions in China, exaggerates filial cardiovascular maldevelopment induced by HCY in a murine model, exacerbating structural abnormalities in the filial cardiac tissue, which is possibly associated with oxidative stress and reduced GATA4 and Nkx2-5 transcription factor expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 877-889, 2017.

Vitamin C protects piglet liver against zearalenone-induced oxidative stress by modulating expression of nuclear receptors PXR and CAR and their target genes

Zearalenone (ZEN), a common mycotoxin found in human food and animal feed, is effectively detoxified by vitamin C by modulation of the nuclear receptor signaling pathway.

Maternal exposure to fine particulate air pollution induces epithelial-to-mesenchymal transition resulting in postnatal pulmonary dysfunction mediated by transforming growth factor-β/Smad3 signaling

Fine particles from air pollution, also called particulate matter, less than 2.5 micrometers in diameter (PM2.5), are a threat to child health. Epidemiological investigations have related maternal exposure to PM2.5 to postnatal respiratory symptoms, such as frequent wheezing, chronic cough, and lung function decrements. However, only few experimental animal studies have been performed to study the effects of PM2.5.The aim of this study was to investigate the effects of maternal exposure to PM2.5 on postnatal pulmonary dysfunction in a rat model and to examine the mechanism of PM2.5-induced morphological pulmonary changes.Timed pregnant Sprague-Dawley rats were treated with PM2.5 (0.1, 0.5, 2.5, or 7.5mg/kg) once every three days from day 0 to 18 of pregnancy. After delivery, pups were sacrificed on postnatal day (PND)1 and 28. The effects of transforming growth factor-beta (TGF-β) on epithelial-mesenchymal transition (EMT) were determined by immunohistochemistry, Western blotting, and quantitative RT-PCR. The offspring underwent pulmonary function measurements on PND28, lung tissues were histopathologically examined, and markers of oxidative stress were measured. Maternally PM2.5-exposed offspring pups displayed significant decreases in lung volume parameters, compliance, and airflow during expiration on PND28. The PM2.5-exposed group showed interstitial proliferation in lung histology, significant oxidative stress in lungs, and up-regulation of TGF-β-induced EMT via increased vimentin and α-smooth muscle actin and decreased E-cadherin levels on PND1 and PND28.These results suggest that EMT up-regulation mediated by the TGF-β/Smad3 pathway plays a role in postnatal pulmonary dysfunction associated with maternal exposure to PM2.5.

Increased Fetal Thymocytes Apoptosis Contributes to Prenatal Nicotine Exposure-induced Th1/Th2 Imbalance in Male Offspring Mice

Nicotine, a definite risk factor during pregnancy, is an immunomodulator. This study was designed to investigate the effects of prenatal nicotine exposure (PNE) on the balance of Th1/Th2 in offspring, and further explore the developmental origin mechanisms from the perspective of fetal thymocytes apoptosis. Pregnant Balb/c mice were administered 1.5 mg/kg nicotine subcutaneously twice per day from gestational day (GD) 9 to GD18. Results showed that PNE could cause a Th2 shift in male offspring, manifested as increased ratio of IgG1/IgG2a, IL-4 production in serum, and IL-4/IFN-γ expression ratio in spleen. Increased apoptosis of total thymocytes and CD4SP and reduced cell proportion of CD4SP were found in PNE male offspring on postnatal day (PND) 14 and PND 49. In the fetuses, decreased body weight and organ index of fetal thymus, histological changes in fetal thymus, reduced CD4SP proportion and increased fetal thymocyte apoptosis were observed in nicotine group. The increased mRNA expression of genes involved in Fas-mediated apoptotic pathway and protein expression of Fas were also detected. In conclusion, PNE could cause a Th2 shift in male offspring mediated by reduced CD4⁺ T cells output, which may result from the increasing apoptosis of total thymocytes and CD4SP.

Air Pollution During Pregnancy and Cord Blood Immune System Biomarkers

OBJECTIVES

We aimed to determine whether average and trimester-specific exposures to ambient measures of nitrogen dioxide (NO2) and particular matter (PM2.5) were associated with elevated cord blood concentrations of immunoglobulin E (IgE) and two epithelial cell produced cytokines: interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP).

METHODS

This study utilized data and biospecimens from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. There were 2001 pregnant women recruited between 2008 and 2011 from 10 Canadian cities. Maternal exposure to NO2 and PM2.5 was estimated using land use regression and satellite-derived models.

RESULTS

We observed statistically significant associations between maternal NO2 exposure and elevated cord blood concentrations of both IL-33 and TSLP among girls but not boys.

CONCLUSIONS

Maternal NO2 exposure may impact the development of the newborn immune system as measured by cord blood concentrations of two cytokines.

Developmental origins of inflammatory and immune diseases

Epidemiological and experimental animal studies show that suboptimal environments in fetal and neonatal life exert a profound influence on physiological function and risk of diseases in adult life. The concepts of the 'developmental programming' and Developmental Origins of Health and Diseases (DOHaD) have become well accepted and have been applied across almost all fields of medicine. Adverse intrauterine environments may have programming effects on the crucial functions of the immune system during critical periods of fetal development, which can permanently alter the immune function of offspring. Immune dysfunction may in turn lead offspring to be susceptible to inflammatory and immune diseases in adulthood. These facts suggest that inflammatory and immune disorders might have developmental origins. In recent years, inflammatory and immune disorders have become a growing health problem worldwide. However, there is no systematic report in the literature on the developmental origins of inflammatory and immune diseases and the potential mechanisms involved. Here, we review the impacts of adverse intrauterine environments on the immune function in offspring. This review shows the results from human and different animal species and highlights the underlying mechanisms, including damaged development of cells in the thymus, helper T cell 1/helper T cell 2 balance disturbance, abnormal epigenetic modification, effects of maternal glucocorticoid overexposure on fetal lymphocytes and effects of the fetal hypothalamic-pituitary-adrenal axis on the immune system. Although the phenomena have already been clearly implicated in epidemiologic and experimental studies, new studies investigating the mechanisms of these effects may provide new avenues for exploiting these pathways for disease prevention.

Can cell proliferation of umbilical cord blood cells reflect environmental exposures?

Environmental hazards were shown to have an impact on cell proliferation (CP). We investigated CP of lymphocytes in umbilical cord blood in relation to prenatal environmental exposures in a sample of 346 Arab-Bedouin women giving birth in a local hospital. Information on subjects' addresses at pregnancy, potential household exposures and demographical status was collected in an interview during hospitalization. This population is usually featured by high rates of neonatal morbidity and multiple environmental exposures, originating from the local industrial park (IP), household hazards and frequent male smoking. A geometric mean CP ratio 2.17 (2.06; 2.29), and was high in women residing in a direction of prevailing winds from the local IP (p value = 0.094) and who gave birth during fall-winter season (p value = 0.024). Women complaining on disturbing exposure to noise had lower CP (p value = 0.015), compared to other women. CP was not indicative of neonatal morbidity. However, our findings suggest that CP of umbilical cord might be modified by environmental exposures. A long-term follow-up of the children is required to assess their developmental outcomes.

A perspective on the developmental toxicity of inhaled nanoparticles

This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.

Association between prenatal exposure to metals and neonatal morbidity

An association between prenatal exposure to (semi-)metals and of neonatal morbidity was assessed by introducing an oxidative stress as a possible intermediate step. An oxidative stress was measured by cell proliferation (CP) ratio in umbilical cord blood cells. Urine samples of 18 out of 58 enrolled women (31%) were positive for (semi-)metals; 25.9% of women were positive for aluminum (Al). The CP ratio was higher (1) in subjects with Al, (2) in mothers to newborns diagnosed as small-for-gestational age (p value = .052), (3) neonates that weighed less (p value = .079), and (4) in women who experienced repeated abortions (p value = .049). Our findings suggest the possibility of metal-induced oxidative stress.