Air pollution exposure during critical time periods in gestation and alterations in cord blood lymphocyte distribution: a cohort of livebirths

Exercise-Mediated Protection against Air Pollution-Induced Immune Damage: Mechanisms, Challenges, and Future Directions

Air pollution, a serious risk factor for human health, can lead to immune damage and various diseases. Long-term exposure to air pollutants can trigger oxidative stress and inflammatory responses (the main sources of immune impairment) in the body. Exercise has been shown to modulate anti-inflammatory and antioxidant statuses, enhance immune cell activity, as well as protect against immune damage caused by air pollution. However, the underlying mechanisms involved in the protective effects of exercise on pollutant-induced damage and the safe threshold for exercise in polluted environments remain elusive. In contrast to the extensive research on the pathogenesis of air pollution and the preventive role of exercise in enhancing fitness, investigations into exercise resistance to injury caused by air pollution are still in their infancy. In this review, we analyze evidence from humans, animals, and cell experiments on the combined effects of exercise and air pollution on immune health outcomes, with an emphasis on oxidative stress, inflammatory responses, and immune cells. We also propose possible mechanisms and directions for future research on exercise resistance to pollutant-induced damage in the body. Furthermore, we suggest strengthening epidemiological studies at different population levels and investigations on immune cells to guide how to determine the safety thresholds for exercise in polluted environments.

Maternal urban particulate matter (SRM 1648a) exposure disrupted the cellular immune homeostasis during early life: The potential attribution of altered placental transcriptome profile

Ambient fine particular matter (PM2.5) exposure has been associated with numerous adverse effects including triggering functional disorders of the placenta and inducing immune imbalance in offspring. However, how maternal PM2.5 exposure impacts immune development during early life is not fully understood. In the current study, we exposed mice with low-, middle-, and high-dose PM2.5 during pregnancy to investigate the potential link between the transcriptional changes in the placenta and immune imbalance in mice offspring induced by PM2.5 exposures. Using flow cytometry, we found that the proportions of B cells, CD3+CD4+ T cells, CD3+CD8+ T cells, and macrophage (Mφ) cells were altered in the blood of PM2.5-exposed mice pups but not dendritic cells (DCs) and natural killer cells (NKs). Using bulk RNA sequencing, we found that PM2.5 exposure altered the transcriptional profile which indicated an inhibition of the complement and coagulation cascades in the placenta. Weighted gene co-expression network analysis (WGCNA) revealed the potential crosstalk between the perturbation of placental gene expression and the changes of immune cell subsets in pups on postnatal day 10 (PND10). Specifically, WGCNA identified a cluster of genes including Defb15, Defb20, Defb25, Cst8, Cst12, and Adam7 that might regulate the core immune cell types in PND10 pups. Although the underlying mechanisms of how maternal PM2.5 exposure induces peripheral lymphocyte disturbance in offspring still remain much unknown, our findings here shed light on the potential role of placental dysfunction in these adverse effects.

The influence of asthma on neuroinflammation and neurodevelopment: From epidemiology to basic models

Asthma is a highly heterogeneous inflammatory disease that can have a significant effect on both the respiratory system and central nervous system. Population based studies and animal models have found asthma to be comorbid with a number of neurological conditions, including depression, anxiety, and neurodevelopmental disorders. In addition, maternal asthma during pregnancy has been associated with neurodevelopmental disorders in the offspring, such as autism spectrum disorders and attention deficit hyperactivity disorder. In this article, we review the most current epidemiological studies of asthma that identify links to neurological conditions, both as it relates to individuals that suffer from asthma and the impacts asthma during pregnancy may have on offspring neurodevelopment. We also discuss the relevant animal models investigating these links, address the gaps in knowledge, and explore the potential future directions in this field.

The Climate Crisis and Breastfeeding: Opportunities for Resilience

The climate crisis is an emerging global challenge that poses potential risks to breastfeeding practices and outcomes. There are multifaceted effects of climate change affecting the breastfeeding dyad across environmental, societal, and human health dimensions. Breastfeeding support in the face of climate change will require solutions at the structural level-healthcare, community, and workplace settings-and at the mother-infant dyad level. Breastfeeding can additionally be an adaptive response to crisis situations and can mitigate some of the environmental challenges associated with climate change. Despite the undeniable significance of climate change on breastfeeding (and vice versa), our perspective as experts in the field is that this topic has not been systematically addressed. Although we highlight some of the challenges, potential solutions, and co-benefits of breastfeeding in the context of climate change, there are numerous issues that could be further explored and necessitate additional preparedness planning.

PM2.5 induces the inflammatory response in rat spleen lymphocytes through autophagy activation of NLRP3 inflammasome

Recent evidence has suggested that fine particulate matter (PM2.5) can induce inflammatory injury in spleen. However, the underlying mechanisms of injury remain enigmatic. In this study, we aim to clarify the inflammatory injury mechanisms of PM2.5 through investigating the crosstalk between autophagy and nod-like receptor protein 3 (NLRP3) inflammasome. The spleen lymphocytes were extracted from SD rats and subjected to PM2.5 and its water-soluble components. The CCK-8 assay was utilized to explore the effects of PM2.5 and its water-soluble components on lymphocytes. Then, the effects of PM2.5 and its water-soluble components exposure on autophagy and NLRP3 inflammasome were detected by qRT-PCR, western blotting, and immunofluorescence staining. The autophagosome production was observed under the transmission electron microscope. The autophagy inhibitor 3-methyladenine (3MA) following PM2.5 water-soluble components was used to investigate the regulation of NLRP3 inflammasome by autophagy. We found that PM2.5 and its water-soluble components decreased the viability of spleen lymphocytes in a dose-dependent manner. PM2.5 exposure and its water-soluble components exposure activated the autophagy and NlRP3 inflammasome, as indicated by an increased expression of LC3, P62, NLRP3, Caspase-1 p10, and increased release of IL-1β. Furthermore, the treatment with autophagy inhibitor 3MA attenuated the production of autophagosome and NLRP3 inflammasome induced by PM2.5 water-soluble components with decreased expression of NLRP3, Caspase-1 p10, and diminished production of IL-1β. These results suggested that PM2.5 and its water-soluble components could induce autophagy and inflammatory response through NLRP3 inflammasome in spleen lymphocytes, while the NLRP3 inflammasome induced by PM2.5 could be significantly alleviated by inhibition of autophagy, further providing new insights for the understanding of spleen injury caused by PM2.5.

Microplastic sources, formation, toxicity and remediation: a review

Microplastic pollution is becoming a major issue for human health due to the recent discovery of microplastics in most ecosystems. Here, we review the sources, formation, occurrence, toxicity and remediation methods of microplastics. We distinguish ocean-based and land-based sources of microplastics. Microplastics have been found in biological samples such as faeces, sputum, saliva, blood and placenta. Cancer, intestinal, pulmonary, cardiovascular, infectious and inflammatory diseases are induced or mediated by microplastics. Microplastic exposure during pregnancy and maternal period is also discussed. Remediation methods include coagulation, membrane bioreactors, sand filtration, adsorption, photocatalytic degradation, electrocoagulation and magnetic separation. Control strategies comprise reducing plastic usage, behavioural change, and using biodegradable plastics. Global plastic production has risen dramatically over the past 70 years to reach 359 million tonnes. China is the world's top producer, contributing 17.5% to global production, while Turkey generates the most plastic waste in the Mediterranean region, at 144 tonnes per day. Microplastics comprise 75% of marine waste, with land-based sources responsible for 80-90% of pollution, while ocean-based sources account for only 10-20%. Microplastics induce toxic effects on humans and animals, such as cytotoxicity, immune response, oxidative stress, barrier attributes, and genotoxicity, even at minimal dosages of 10 μg/mL. Ingestion of microplastics by marine animals results in alterations in gastrointestinal tract physiology, immune system depression, oxidative stress, cytotoxicity, differential gene expression, and growth inhibition. Furthermore, bioaccumulation of microplastics in the tissues of aquatic organisms can have adverse effects on the aquatic ecosystem, with potential transmission of microplastics to humans and birds. Changing individual behaviours and governmental actions, such as implementing bans, taxes, or pricing on plastic carrier bags, has significantly reduced plastic consumption to 8-85% in various countries worldwide. The microplastic minimisation approach follows an upside-down pyramid, starting with prevention, followed by reducing, reusing, recycling, recovering, and ending with disposal as the least preferable option.

The relationship between air pollution and multimorbidity: Can two birds be killed with the same stone?

Air pollution and multimorbidity are two of the most important challenges for Public Health worldwide. Although there is a large body of evidence linking air pollution with the development of different single chronic conditions, the evidence about the relationship between air pollution and multimorbidity (the co-occurrence of multiple long-term conditions) is sparse. To obtain evidence about this relationship could be challenging and different aspects should be considered, such as its multifaceted and complex nature, the specific pollutants and their potential influence on health, their levels of exposure over time, or the data that could be used for its study. This evidence could be instrumental to inform the development of new recommendations and measures to reduce harmful levels of air pollutants, as means to prevent the development of multimorbidity and reduce its burden.

Neurodevelopmental toxicity induced by airborne particulate matter

Airborne particulate matter (PM), the primary component associated with health risks in air pollution, can negatively impact human health. Studies have shown that PM can enter the brain by inhalation, but data on the exact quantity of particles that reach the brain are unknown. Particulate matter exposure can result in neurotoxicity. Exposure to PM poses a greater health risk to infants and children because their nervous systems are not fully developed. This review paper highlights the association between PM and neurodevelopmental toxicity (NDT). Exposure to PM can induce oxidative stress and inflammation, potentially resulting in blood-brain barrier damage and increased susceptibility to development of neurodevelopmental disorders (NDD), such as autism spectrum disorders and attention deficit disorders. In addition, human and animal exposure to PM can induce microglia activation and epigenetic alterations and alter the neurotransmitter levels, which may increase risks for development of NDD. However, the systematic comparisons of the effects of PM on NDD at different ages of exposure are deficient. The elucidation of PM exposure risks and NDT in children during the early developmental stages are of great importance. The synthesis of current research may help to identify markers and mechanisms of PM-induced neurodevelopmental toxicity, allowing for the development of strategies to prevent permanent damage of developing brain.

A comprehensive understanding of ambient particulate matter and its components on the adverse health effects based from epidemiological and laboratory evidence

The impacts of air pollution on public health have become a great concern worldwide. Ambient particulate matter (PM) is a major air pollution that comprises a heterogeneous mixture of different particle sizes and chemical components. The chemical composition and physicochemical properties of PM change with space and time, which may cause different impairments. However, the mechanisms of the adverse effects of PM on various systems have not been fully elucidated and systematically integrated. The Adverse Outcome Pathway (AOP) framework was used to comprehensively illustrate the molecular mechanism of adverse effects of PM and its components, so as to clarify the causal mechanistic relationships of PM-triggered toxicity on various systems. The main conclusions and new insights of the correlation between public health and PM were discussed, especially at low concentrations, which points out the direction for further research in the future. With the deepening of the study on its toxicity mechanism, it was found that PM can still induce adverse health effects with low-dose exposure. And the recommended Air Quality Guideline level of PM_2.5 was adjusted to 5 μg/m³ by World Health Organization, which meant that deeper and more complex mechanisms needed to be explored. Traditionally, oxidative stress, inflammation, autophagy and apoptosis were considered the main mechanisms of harmful effects of PM. However, recent studies have identified several emerging mechanisms involved in the toxicity of PM, including pyroptosis, ferroptosis and epigenetic modifications. This review summarized the comprehensive evidence on the health effects of PM and the chemical components of it, as well as the combined toxicity of PM with other air pollutants. Based on the AOP Wiki and the mechanisms of PM-induced toxicity at different levels, we first constructed the PM-related AOP frameworks on various systems.

In Utero Ultrafine Particulate Exposure Yields Sex- and Dose-Specific Responses to Neonatal Respiratory Syncytial Virus Infection

Exposure to particulate matter (PM) is associated with lower respiratory tract infections. The role of ultrafine particles (UFPs, ≤0.1 μm) in respiratory disease is not fully elucidated, especially in models of immunologically immature populations. To characterize the effects of maternal UFP exposure on neonatal infection, we exposed time-mated C57Bl/6n mice to filtered air or UFPs at a low dose (LD, ∼55 μg/m3) and high dose (HD, ∼275 μg/m3) throughout gestation. At 5 days of age, offspring were infected with a respiratory syncytial virus (RSV) strain known to mimic infant infection or sham control. Offspring body weights were significantly reduced in response to infection in the LD RSV group, particularly females. Pulmonary gene expression analysis demonstrated significantly increased levels of oxidative stress- and inflammation-related genes in HD-exposed male offspring in sham and RSV-infected groups. In males, the highest grade of inflammation was observed in the HD RSV group, whereas in females, the LD RSV group showed the most marked inflammation. Overall, findings highlight neonatal responses are dependent on offspring sex and maternal UFP dose. Importantly, infant RSV pathology may be enhanced following even low dose UFP exposure signifying the importance of preventing maternal exposure.

PM2.5-Related Neonatal Infections: A Global Burden Study from 1990 to 2019

Background: Long-term exposure to fine particulate matter (PM2.5) may increase the risk of neonatal infections. To show the effects of PM2.5 on neonatal infections as well as the trends of the effect, we studied the burden measured by the age-standardized mortality rate (ASMR) and the age-standardized disability-adjusted life years rate (ASDR) and its trends with the socio-demographic index in 192 countries and regions from 1990 to 2019. Methods: This is a retrospective study that uses the Global Burden of Disease Study 2019 database. The age-standardized mortality rate and age-standardized disability-adjusted life years rate are used to measure the burden of PM2.5-related neonatal infections in different countries and regions. The annual percentage changes and the average annual percentage changes are used to reflect the trends over the years (1990–2019) and are calculated using a Joinpoint model. The relationship of the socio-demographic index with the ASMR and ASDR is calculated and described using Gaussian process regression. Results: With the rapid increase in the global annual average of PM2.5, the global burden of PM2.5-related neonatal infections has increased since 1990, especially in early neonates, boys, and low-middle SDI regions. Globally, the ASMR and ASDR of PM2.5-related neonatal infections in 2019 were 0.21 (95% CI: 0.14, 0.31) and 19.06 (95% CI: 12.58, 27.52) per 100,000 people, respectively. From 1990 to 2019, the ASMR and ASDR increased by 72.58% and 73.30%, and their average annual percentage changes were 1.9 (95% CI: 1.3, 2.6) and 2.0 (95% CI: 1.3, 2.6), respectively. When the socio-demographic index was more than 0.60, it was negatively related to the burden of PM2.5-related neonatal infections. Surprisingly, the burden in low SDI regions was lower than it was in low-middle and middle SDI regions, while high-middle and high-SDI regions showed decreasing trends. Interpretation: Boys bore a higher PM2.5-related neonatal burden, with male fetuses being more likely to be affected by prenatal exposure to PM2.5 and having less of a biological survival advantage. Poverty was the root cause of the burden. Higher SDI countries devoted more resources to improving air quality, the coverage of medical services, the accessibility of institutional delivery, and timely referral to reduce the disease burden. The burden in low SDI regions was lower than that in low-middle and middle SDI regions. One reason was that the benefits of medical services were lower than the harm to health caused by environmental pollution in low-middle and middle SDI regions. Moreover, the underreporting of data is more serious in low SDI countries. Conclusions: In the past 30 years, the global burden of PM2.5-related neonatal infections has increased, especially in early neonates, boys, and low-middle SDI regions. The huge difference compared to higher SDI countries means that lower SDI countries have a long way to go to reduce the disease burden. Policy makers should appropriately allocate medical resources to boys and early newborns and pay more attention to data under-reporting in low SDI countries. In addition, it is very necessary to promulgate policies to prevent and control air pollution in countries with large and increasing exposure to PM2.5 pollution.

Safe in the womb? Effects of air pollution to the unborn child and neonates

OBJECTIVE

In this brief review, the authors focus on the effects of gestational exposures to urban air pollution on fetal development and neonatal outcomes.

SOURCE OF DATA

In this review the authors used PubMed, Web of Science and SciELO research platforms, analyzing papers from the last 30 years.

SUMMARY OF THE FINDINGS

Epidemiological and experimental evidence agree that gestational exposure to air pollution in urban increases the risks for low birth weight, preterm birth, congenital malformation, intrauterine growth restriction, and neonatal mortality. Furthermore, exposures are associated with increased risks for preeclampsia, hypertension, gestational diabetes.

CONCLUSIONS

Therefore, it is time for greater involvement and engagement of the health sector in the discussion of public policies that may affect the quality of the environment, and that directly or indirectly impact the health of those who were not yet born.

Susceptibility of patients with chronic obstructive pulmonary disease to heart rate difference associated with the short-term exposure to metals in ambient fine particles: A panel study in Beijing, China

Susceptibility of patients with chronic obstructive pulmonary disease (COPD) to cardiovascular autonomic dysfunction associated with exposure to metals in ambient fine particles (PM_2.5, particulate matter with aerodynamic diameter ≤2.5 µm) remains poorly evidenced. Based on the COPDB (COPD in Beijing) panel study, we aimed to compare the associations of heart rate (HR, an indicator of cardiovascular autonomic function) and exposure to metals in PM_2.5 between 53 patients with COPD and 82 healthy controls by using linear mixed-effects models. In all participants, the HR levels were significantly associated with interquartile range increases in the average concentrations of Cr, Zn, and Pb, but the strength of the associations differed by exposure time (from 1.4% for an average 9 days (d) Cr exposure to 3.5% for an average 9 d Zn exposure). HR was positively associated with the average concentrations of PM_2.5 and certain metals only in patients with COPD. Associations between HR and exposure to PM_2.5, K, Cr, Mn, Ni, Cu, Zn, As, and Se in patients with COPD significantly differed from those in health controls. Furthermore, association between HR and Cr exposure was robust in COPD patients. In conclusion, our findings indicate that COPD could exacerbate difference in HR following exposure to metals in PM_2.5.

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.

Preliminary Evidence of Differentially Induced Immune Responses by Microparticle-adsorbed LPS in Patients with Crohn's Disease

Inorganic microparticles are ubiquitous in the modern Western diet present as food additives and are actively scavenged by microfold (M) cells overlying human intestinal lymphoid aggregates. In Crohn's disease (CD), inflammation is caused by the inability of the intestinal mucosa to sustain tolerance to gut luminal factors including bacteria and their by-products. Having large, highly charged surface areas dietary particles can avidly bind biomolecules such as lipopolysaccharide (LPS). The aim of this paper was to examine whether the dietary particle, titanium dioxide (TiO₂), modified cellular immune responses to LPS differently in peripheral blood mononuclear cells (PBMC) from CD patients compared with healthy controls. Our data showed that LPS-associated particles predominantly stimulated release of IL-1β and induced concurrent cell death in peripheral monocytes following particle uptake in both health and disease. In addition, IL-1β release was increased more in CD patients compared with controls following particle stimulation. In conclusion, LPS adsorption to dietary particulates provides a mechanism for stimulation of phagocytic mononuclear cells and may cause aggravation of mucosal immune responses in inflammatory conditions of the bowel such as CD, irritable bowel syndrome, and autism spectrum disorder and schizophrenia associated gastrointestinal conditions, by immune priming mediated through increased production of pro-inflammatory cytokines.

Seasonal modulation of antibody response to diphtheria-tetanus-pertussis vaccination in infants: a cohort study in rural Gambia

BACKGROUND

In rural Gambia, rates of malnutrition and infection are higher during the annual rainy/'hungry' season (June-October) in comparison to the dry/'harvest' season (November-May). The effects of this seasonal pattern on an infant's immune development and their capacity to respond to childhood vaccinations remain unclear. The aim of the current analysis was to determine whether antibody responses to diphtheria-tetanus-pertussis (DTP) vaccinations in infants differ between seasons.

METHODS

Infants received the DTP vaccine at 8, 12 and 16 weeks of age and antibody titres were measured in blood samples collected at 12 (n = 710) and 24 (n = 662) weeks of age. Mean DTP antibody titres, adjusted for maternal and infant confounders, were compared by t-tests and the effect sizes of the mean differences were calculated between seasons at mid-gestation (20 weeks gestation) and first vaccination (8 weeks of infant age).

RESULTS

A smaller number of infants received their first vaccination during the rainy/hungry season months compared to the dry/harvest season (n = 224 vs. n = 486). At 12 weeks, infants vaccinated during the rainy/hungry season had lower weight-for-length Z-scores (p = 0.01) and were more likely to be anaemic (p < 0.001). Their mothers, however, were pregnant mostly during the dry/harvest season, had higher weight gain (p < 0.001) and were less likely to be anaemic during pregnancy (p < 0.001). At 12 weeks, infants vaccinated during the rainy/hungry season had significantly higher mean diphtheria, tetanus and pertussis antibody titres; by 62.3, 16.9 and 19.7%, respectively (all, p < 0.001). However, at 24 weeks, they had lower mean anti-diphtheria titres (by 20.6%, p < 0.001) compared with infants vaccinated during the dry/harvest season, and no differences were observed in mean tetanus and pertussis antibody titres by vaccination season.

CONCLUSIONS

Infant antibody response to the primary dose of the DTP vaccine was influenced by both season of pregnancy and infancy, although effects were diminished following three doses. Environmental exposures, including nutrition, to both the mother and infant are hypothesised as likely drivers of these seasonal effects.

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.

Environmental Air Pollutants Inhaled during Pregnancy Are Associated with Altered Cord Blood Immune Cell Profiles

Air pollution exposure during pregnancy may be a risk factor for altered immune maturation in the offspring. We investigated the association between ambient air pollutants during pregnancy and cell populations in cord blood from babies born to mothers with asthma enrolled in the Breathing for Life Trial. For each patient (n = 91), daily mean ambient air pollutant levels were extracted during their entire pregnancy for sulfur dioxide (SO₂), nitric oxide, nitrogen dioxide, carbon monoxide, ozone, particulate matter <10 μm (PM₁₀) or <2.5 μm (PM_2.5), humidity, and temperature. Ninety-one cord blood samples were collected, stained, and assessed using fluorescence-activated cell sorting (FACS). Principal Component (PC) analyses of both air pollutants and cell types with linear regression were employed to define associations. Considering risk factors and correlations between PCs, only one PC from air pollutants and two from cell types were statistically significant. PCs from air pollutants were characterized by higher PM_2.5 and lower SO₂ levels. PCs from cell types were characterized by high numbers of CD8 T cells, low numbers of CD4 T cells, and by high numbers of plasmacytoid dendritic cells (pDC) and low numbers of myeloid DCs (mDCs). PM_2.5 levels during pregnancy were significantly associated with high numbers of pDCs (p = 0.006), and SO₂ with high numbers of CD8 T cells (p = 0.002) and low numbers of CD4 T cells (p = 0.011) and mDCs (p = 4.43 × 10⁻⁶) in cord blood. These data suggest that ambient SO₂ and PM_2.5 exposure are associated with shifts in cord blood cell types that are known to play significant roles in inflammatory respiratory disease in childhood.

Maternal exposure to O3 and NO2 may increase the risk of newborn congenital hypothyroidism: a national data-based analysis in China

Maternal exposure to air pollution during pregnancy is associated with adverse outcomes in the offspring, but limited studies focused on the impacts of gaseous air pollution on newborn congenital hypothyroidism (CH). Therefore, a national data-based analysis was conducted to explore the association between maternal exposure to gaseous air pollution and the incidence of CH in China. Annual average exposure levels of SO₂, NO₂, CO, and O₃ from January 1, 2014, to December 30, 2014, were acquired from the Chinese Air Quality Online Monitoring and Analysis Platform. The annual incidence of newborn CH from October 1, 2014, to September 30, 2015, was collected from the Chinese Maternal and Child Health Surveillance Network. Temperature and toxic metal in wastewater in 2014 were also collected as covariates. Maternal exposure to O₃ and NO₂ in 1 μg/m³ level increment was positively associated with newborn CH, with an OR of 1.055 (95% CI 1.011, 1.102) and 1.097 (95% CI 1.019, 1.182) after adjusting for covariates completely. Compared with the lowest level of O₃, maternal exposure to the 4th quartile of O₃ was positively associated with newborn CH (OR 1.393, 95% CI 1.081, 1.794) after adjusting for covariates completely. And the 3rd and 4th quartiles of NO₂ were associated positively with CH (OR 1.576, 95% CI 1.025, 2.424, and OR 1.553, 95% CI 0.999, 2.414, respectively) compared with the lowest level of NO₂. By fitting the ROC curve, 93.688 μg/m³ in O₃ might be used as cutoff to predict the incidence of newborn CH in China.

Air pollution from traffic during pregnancy impairs newborn's cord blood immune cells: The NELA cohort

BACKGROUND

Hazards of traffic-related air pollution (TRAP) on the developing immune system are poorly understood. We sought to investigate the effects of prenatal exposure to TRAP on cord blood immune cell distributions; and to identify gestational windows of susceptibility.

METHODS

In-depth immunophenotyping of cord blood leukocyte and lymphocyte subsets was performed by flow cytometry in 190 newborns embedded in the Nutrition in Early Life and Asthma (NELA) birth cohort (2015-2018). Long-term (whole pregnancy and trimesters) and short-term (15-days before delivery) residential exposures to traffic-related nitrogen dioxide (NO₂), particulate matter (PM_2.5 and PM₁₀), and ozone (O₃) were estimated using dispersion/chemical transport modelling. Associations between TRAP concentrations and cord blood immune cell counts were assessed using multivariate Poisson regression models.

RESULTS

Mean number of natural killer (NK) cells decreased 15% in relation to higher NO₂ concentrations (≥36.4 μg/m3) during whole pregnancy (incidence relative risk (IRR), 0.85; 95% CI, 0.72, 0.99), with stronger associations in the first trimester. Higher PM_2.5 concentrations (≥13.3 μg/m³) during whole pregnancy associated with a reduced mean number of cytotoxic T cells (IRR, 0.88; 95% CI, 0.78, 0.99). Newborns exposed to higher PM₁₀ (≥23.6 μg/m³) and PM_2.5 concentrations during the first and third trimester showed greater mean number of helper T type 1 (Th1) cells (P < 0.05). Decreased number of regulatory T (Treg) cells was associated with greater short-term NO₂ (IRR, 0.90; 95% CI, 0.80, 1.01) and PM₁₀ (IRR, 0.88; 95% CI, 0.77, 0.99) concentrations.

CONCLUSIONS

Prenatal exposure to TRAP, particularly in early and late gestation, impairs fetal immune system development through disturbances in cord blood leukocyte and lymphocyte distributions.

A review of human and animals exposure to polycyclic aromatic hydrocarbons: Health risk and adverse effects, photo-induced toxicity and regulating effect of microplastics

Polycyclic aromatic hydrocarbons (PAHs) are one of the most widely distributed persistent organic pollutants (POPs) in the environmental media. PAHs have been widely concerned due to their significant health risk and adverse effects to human and animals. Currently, the main sources of PAHs in the environment are the incomplete combustion of fossil fuels, as well as municipal waste incineration and agricultural non-surface source emissions. In this work, the scope of our attention includes 16 typical PAHs themselves without involving their metabolites and industrial by-products. Exposure of human and animals to PAHs can lead to a variety of adverse effects, including carcinogenicity and teratogenicity, genotoxicity, reproductive- and endocrine-disrupting effects, immunotoxicity and neurotoxicity, the type and severity of which depend on a variety of factors. On the other hand, the regulatory effect of microplastics (MPs) on the bio-toxicity and bioaccumulation capacity of PAHs has now gradually attracted attention. We critically reviewed the adsorption capacity and mechanisms of MPs on PAHs as well as the effects of MPs on PAHs toxicity, thus highlighting the importance of paying attention to the joint bio-toxicity caused by PAHs-MPs interactions. In addition, due to the extensive nature of the common exposure pathway of PAHs and ultraviolet ray, an accurate understanding of biological processes exposed to both PAHs and UV light is necessary to develop effective protective strategies. Finally, based on the above critical review, we highlighted the research gaps and pointed out the priority of further studies.

Exposure to ambient air pollution during pregnancy and inflammatory biomarkers in maternal and umbilical cord blood: The Healthy Start study

BACKGROUND

Air pollution exposure during pregnancy has been associated with adverse pregnancy and birth outcomes. Inflammation has been proposed as a potential link. We estimated associations between air pollution exposure during pregnancy and inflammatory biomarkers in maternal and cord blood. We evaluated whether maternal inflammation was associated with infant outcomes.

METHODS

Among 515 mother-infant dyads in the Healthy Start study (2009-2014), trimester-long, 7- and 30-day average concentrations of particulate matter ≤2.5 μm (PM_2.5) and ozone (O₃) during pregnancy were estimated, using inverse-distance-weighted interpolation. Inflammatory biomarkers were measured in maternal blood in mid-pregnancy (C-reactive protein [CRP], Interleukin [IL]-6, and tumor necrosis factor-α [TNFα]) and in cord blood at delivery (CRP, IL-6, IL-8, IL-10, monocyte chemoattractant protein-1 [MCP-1], and TNFα). We used linear regression to estimate associations between pollutants and inflammatory biomarkers and maternal inflammatory biomarkers and infant weight and body composition.

RESULTS

There were positive associations between PM_2.5 during certain exposure periods and maternal IL-6 and TNFα. There were negative associations between recent O₃ and maternal CRP, IL-6, and TNFα and positive associations between trimester-long O₃ exposure and maternal inflammatory biomarkers, though some 95% confidence intervals included the null. Patterns were inconsistent for associations between PM_2.5 and O₃ and cord blood inflammatory biomarkers. No consistent associations between maternal inflammatory biomarkers and infant outcomes were identified.

CONCLUSIONS

Air pollution exposure during pregnancy may impact maternal inflammation. Further investigations should examine the health consequences for women and infants of elevated inflammatory biomarkers associated with air pollution exposure during pregnancy.

Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

Urinary polycyclic aromatic hydrocarbons concentrations and hepatitis B antibody serology in the United States (NHANES, 2003-2014)

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that are hepatotoxic and immunotoxic. PAH exposure may modulate hepatitis B immunology.

OBJECTIVE

We used data from 6 cycles of the National Health and Nutrition Examination Survey (2003-2014) to evaluate the associations between urinary PAH metabolites and hepatitis B serology.

METHODS

This analysis included individuals who self-reported receiving ≥3 doses of hepatitis B vaccine and urinary PAH metabolites (i.e. 1-napthol, 2-napthol, 3-fluorene, 2-fluorene, 1-phenanthrene, 1-pyrene, and total PAH [sum of all metabolites]). Separate logistic regression models assessed the association between hepatitis B vaccination status (i.e. individuals who were immune due to vaccination or susceptible) and tertiles of urinary PAH. Models were adjusted for age, gender, race/ethnicity, survey cycle, family income to poverty ratio, BMI, country of birth, serum cotinine, and urinary creatinine.

RESULTS

Among participants who reported receiving ≥3 doses of vaccine and had no antibodies indicating a history of hepatitis B infection and/or current hepatitis B infection, dose-response relationships were observed where individuals with the lowest odds of serology indicating a response to the hepatitis B vaccine (i.e., anti-HBs⁺, anti-HBc^-, and HBsAg^-) were in the highest tertile of 2-Napthol (adjusted Odds Ratio [aOR]: 0.70, 95% confidence interval [CI]: 0.54, 0.91), 3-Napthol (aOR: 0.68, 95% CI: 0.53, 0.87), 2-Fluorene (aOR: 0.61, 95% CI: 0.54, 0.86), 1-Phenanthrene (aOR: 0.79, 95% CI: 0.65, 0.97), 1-Pyrene (aOR): 0.68, 95% CI: 0.55, 0.83), and total PAH (aOR: 0.73, 95% CI: 0.56, 0.95) had the compared to the lowest tertile.

CONCLUSION

This cross-sectional study supports a hypothesis that PAH exposures experienced by the general US population may modulate hepatitis B vaccine induced immunity. Given the ubiquity of PAH exposures in the US, additional research is warranted to explore the effects of chronic PAH exposures on hepatitis B related humoral immunity.

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.

Prenatal PM2.5 exposure and vitamin D-associated early persistent atopic dermatitis via placental methylation

BACKGROUND

The effects of prenatal particulate matter with an aerodynamic diameter ranging from 0.1 μm to 2.5 μm (PM_2.5) and vitamin D on atopic dermatitis (AD) phenotypes have not been evaluated. DNA methylation and cord blood (CB) vitamin D could represent a plausible link between prenatal PM_2.5 exposure and AD in an offspring.

OBJECTIVE

To determine the critical windows of prenatal PM_2.5 exposure on the AD phenotypes, if vitamin D modulated these effects, and if placental DNA methylation mediated these effects on AD in offspring.

METHODS

Mother-child pairs were enrolled from the birth cohort of the Cohort for Childhood Origin of Asthma and allergic diseases (COCOA) study. PM_2.5 was estimated by land-use regression models, and CB vitamin D was measured by chemiluminescence immunoassay. AD was identified by the parental report of a physician's diagnosis. We defined the following 4 AD phenotypes according to onset age (by the age of 2 years) and persistence (by the age of 3 years): early-onset transient and persistent, late onset, and never. Logistic regression analysis and Bayesian distributed lag interaction model were used. DNA methylation microarray was analyzed using an Infinium Human Methylation EPIC BeadChip (Illumina, San Diego, California) in placenta.

RESULTS

PM_2.5 exposure during the first trimester of pregnancy, especially during 6 to 7 weeks of gestation, was associated with early-onset persistent AD. This effect increased in children with low CB vitamin D, especially in those with PM_2.5 exposure during 3 to 7 weeks of gestation. AHRR (cg16371648), DPP10 (cg19211931), and HLADRB1 (cg10632894) were hypomethylated in children with AD with high PM_2.5 and low CB vitamin D.

CONCLUSION

Higher PM_2.5 during the first trimester of pregnancy and low CB vitamin D affected early-onset persistent AD, and the most sensitive window was 6 to 7 weeks of gestation. Placental DNA methylation mediated this effect.

Why Do Intrauterine Exposure to Air Pollution and Cigarette Smoke Increase the Risk of Asthma?

The prevalence of childhood asthma is increasing worldwide and increased in utero exposure to environmental toxicants may play a major role. As current asthma treatments are not curative, understanding the mechanisms underlying the etiology of asthma will allow better preventative strategies to be developed. This review focuses on the current understanding of how in utero exposure to environmental factors increases the risk of developing asthma in children. Epidemiological studies show that maternal smoking and particulate matter exposure during pregnancy are prominent risk factors for the development of childhood asthma. We discuss the changes in the developing fetus due to reduced oxygen and nutrient delivery affected by intrauterine environmental change. This leads to fetal underdevelopment and abnormal lung structure. Concurrently an altered immune response and aberrant epithelial and mesenchymal cellular function occur possibly due to epigenetic reprograming. The sequelae of these early life events are airway remodeling, airway hyperresponsiveness, and inflammation, the hallmark features of asthma. In summary, exposure to inhaled oxidants such as cigarette smoking or particulate matter increases the risk of childhood asthma and involves multiple mechanisms including impaired fetal lung development (structural changes), endocrine disorders, abnormal immune responses, and epigenetic modifications. These make it challenging to reduce the risk of asthma, but knowledge of the mechanisms can still help to develop personalized medicines.

Ambient air pollution exposure and gestational diabetes mellitus in Guangzhou, China: A prospective cohort study

BACKGROUND

Evidence concerning the effect of ambient air pollution exposure on gestational diabetes mellitus (GDM) is limited. No published studies have examined maternal weekly air pollution exposure and GDM, and the possible effect modification by folic acid supplementation has not been assessed.

OBJECTIVES

To evaluate the association between air pollution exposure and GDM at trimester and weekly levels, and to explore the potential effect modification by folic acid supplementation.

METHODS

A total of 5421 pregnant women were recruited during 2011-2014 in Guangzhou, China. Daily PM_2.5, PM₁₀, SO₂ and NO₂ levels were collected from 10 monitoring stations. Individual's exposure during pregnancy was estimated using inverse-distance weighting approach. Binary logistic regression was used to examine the trimester-specific association between air pollution exposure and GDM. Distributed lag models (DLMs) were applied to estimate maternal weekly air pollution exposure and GDM. Stratified analyses by folic acid supplementation and interaction test were performed.

RESULTS

The GDM incidence was 11.69%. An interquartile range (IQR) increase in first trimester SO₂ was associated with increased GDM risk in the single pollutant model, the adjusted odds ratio (aOR) and 95% confidence interval (CI) was 1.22 (1.02-1.47). In DLMs, an IQR increase in SO₂ during 4th to 10th gestational weeks was associated with increased GDM risk, with the strongest effect in the 7th gestational week. When stratified by maternal folic acid supplementation, first trimester exposure to SO₂ was associated with increased GDM risk among women taking folic acid supplements (aOR = 1.25, 95% CI: 1.03-1.53) and P value for interaction was 0.13. No significant effects were observed for PM_2.5, PM₁₀ and NO₂.

CONCLUSION

First trimester exposure to SO₂ was associated with increased GDM risk, especially during the 4th to 10th gestational weeks. The effect might be stronger among women taking folic acid supplements.

Particulate matter at third trimester and respiratory infection in infants, modified by GSTM1

OBJECTIVES

To investigate the association between particulate matter with an aerodynamic diameter of less than 2.5 μm (PM_2.5 ) exposure during each trimester of pregnancy and development of lower respiratory tract infections (LRTIs) during the first 3 years of life and whether GSTM1 gene polymorphisms modify these effects.

METHODS

This study included 1,180 mother-child pairs from the Cohort for Childhood Origin of Asthma and allergic diseases. The PM_2.5 levels during pregnancy were estimated by residential address using land-use regression models based on a national monitoring system. A diagnosis of LRTIs was based on a parental report of a physician's diagnosis. Real-time polymerase chain reaction was used for GSTM1 genotyping.

RESULTS

Higher PM_2.5 exposure during the third trimester was associated with LRTIs at 1 year of age (aRR, 1.06; 95% CI, 1.00-1.13). This result did not change after adjusting for PM_2.5 exposures during the first and second trimesters (aRR, 1.06; 95% CI, 0.99-1.13). This association was significant after adjusting for PM_2.5 exposures during first year of age (aRR, 1.08; 95% CI, 1.02-1.15) and exposures to NO₂ and ozone at the third trimester (aRR, 1.07; 95% CI, 1.00-1.16). In addition, PM_2.5 exposure during the third trimester increased the risk of LRTIs at 1 year of age in cases with the GSTM1 null genotype (aRR, 1.26; 95% CI, 1.01-1.57; P for interaction .20).

CONCLUSION

Higher PM_2.5 exposure during the third trimester of pregnancy may increase the susceptibility to LRTIs at 1 year of age. This effect is modified by GSTM1 gene polymorphisms.

Protective Effect of Breastfeeding on the Adverse Health Effects Induced by Air Pollution: Current Evidence and Possible Mechanisms

Air pollution is a major social, economic, and health problem around the world. Children are particularly susceptible to the negative effects of air pollution due to their immaturity and excessive growth and development. The aims of this narrative review were to: (1) summarize evidence about the protective effects of breastfeeding on the adverse health effects of air pollution exposure, (2) define and describe the potential mechanisms underlying the protective effects of breastfeeding, and (3) examine the potential effects of air pollution on breastmilk composition and lactation. A literature search was conducted using electronic databases. Existing evidence suggests that breastfeeding has a protective effect on adverse outcomes of indoor and outdoor air pollution exposure in respiratory (infections, lung function, asthma symptoms) and immune (allergic, nervous and cardiovascular) systems, as well as under-five mortality in both developing and developed countries. However, some studies reported no protective effect of breastfeeding or even negative effects of breastfeeding for under-five mortality. Several possible mechanisms of the breastfeeding protective effect were proposed, including the beneficial influence of breastfeeding on immune, respiratory, and nervous systems, which are related to the immunomodulatory, anti-inflammatory, anti-oxidant, and neuroprotective properties of breastmilk. Breastmilk components responsible for its protective effect against air pollutants exposure may be long chain polyunsaturated fatty acids (LC PUFA), antioxidant vitamins, carotenoids, flavonoids, immunoglobins, and cytokines, some of which have concentrations that are diet-dependent. However, maternal exposure to air pollution is related to increased breastmilk concentrations of pollutants (e.g., Polycyclic aromatic hydrocarbons (PAHs) or heavy metals in particulate matter (PM)). Nonetheless, environmental studies have confirmed that breastmilk’s protective effects outweigh its potential health risk to the infant. Mothers should be encouraged and supported to breastfeed their infants due to its unique health benefits, as well as its limited ecological footprint, which is associated with decreased waste production and the emission of pollutants.

The association of early-life exposure to ambient PM2.5 and later-childhood height-for-age in India: an observational study

BACKGROUND

Children in India are exposed to high levels of ambient fine particulate matter (PM2.5). However, population-level evidence of associations with adverse health outcomes from within the country is limited. The aim of our study is to estimate the association of early-life exposure to ambient PM2.5 with child health outcomes (height-for-age) in India.

METHODS

We linked nationally-representative anthropometric data from India's 2015-2016 Demographic and Health Survey (n = 218,152 children under five across 640 districts of India) with satellite-based PM2.5 exposure (concentration) data. We then applied fixed effects regression to assess the association between early-life ambient PM2.5 and subsequent height-for-age, analyzing whether deviations in air pollution from the seasonal average for a particular place are associated with deviations in child height from the average for that season in that place, controlling for trends over time, temperature, and birth, mother, and household characteristics. We also explored the timing of exposure and potential non-linearities in the concentration-response relationship.

RESULTS

Children in the sample were exposed to an average of 55 μ g/m3 of PM2.5 in their birth month. After controlling for potential confounders, a 100 μg/m3 increase in PM2.5 in the month of birth was associated with a 0.05 [0.01-0.09] standard deviation reduction in child height. For an average 5 year old girl, this represents a height deficit of 0.24 [0.05-0.43] cm. We also found that exposure to PM2.5 in the last trimester in utero and in the first few months of life are significantly (p < 0.05) associated with child height deficits. We did not observe a decreasing marginal risk at high levels of exposure.

CONCLUSIONS

India experiences some of the worst air pollution in the world. To our knowledge, this is the first study to estimate the association of early-life exposure to ambient PM2.5 on child height-for-age at the range of ambient pollution exposures observed in India. Because average exposure to ambient PM2.5 is high in India, where child height-for-age is a critical challenge in human development, our results highlight ambient air pollution as a public health policy priority.

Impacts of air pollution, temperature, and relative humidity on leukocyte distribution: An epigenetic perspective

BACKGROUND

Exploring the associations of air pollution and weather variables with blood leukocyte distribution is critical to understand the impacts of environmental exposures on the human immune system.

OBJECTIVES

As previous analyses have been mainly based on data from cell counters, which might not be feasible in epidemiologic studies including large populations of long-stored blood samples, we aimed to expand the understanding of this topic by employing the leukocyte distribution estimated by DNA methylation profiles.

METHODS

We measured DNA methylation profiles in blood samples using Illumina HumanMethylation450 BeadChip from 1519 visits of 774 Caucasian males participating in the Normative Aging Study. Leukocyte distribution was estimated using Houseman's and Horvath's algorithms. Data on air pollution exposure, temperature, and relative humidity within 28 days before each blood draw was obtained.

RESULTS

After fully adjusting for potential covariates, PM_2.5, black carbon, particle number, carbon monoxide, nitrogen dioxide, sulfur dioxide, temperature, and relative humidity were associated with the proportions of at least one subtype of leukocytes. Particularly, an interquartile range-higher 28-day average exposure of PM_2.5 was associated with 0.147-, 0.054- and 0.101-unit lower proportions (z-scored) of plasma cells, naïve CD8+ T cells, and natural killers, respectively, and 0.059- and 0.161-unit higher proportions (z-scored) of naïve CD4+ T cells and CD8+ T cells, respectively.

CONCLUSIONS

Our study suggests that short-term air pollution exposure, temperature, and relative humidity are associated with leukocyte distribution. Our study further provides a successful attempt to use epigenetic patterns to assess the influences of environmental exposures on human immune profiles.

Air pollution exposure and immunological and systemic inflammatory alterations among schoolchildren in China

Exposure to air pollution is associated with an increased risk of respiratory infection, to which children are more susceptible than adults. However, epidemiological evidence regarding the association of chronic exposure to air pollution with the immune and systemic inflammatory function of children is scarce, especially in the context of higher exposure levels. In this study, we included 163 chronically exposed schoolchildren from a polluted area and 110 schoolchildren from a control area in Licheng district, Jinan, China. Immune biomarkers, including the absolute counts of lymphocyte subsets and the levels of immunoglobulins G, A, and M, C3, and C4 were determined. To explore the related biological process of altered immune biomarkers, 2 systemic inflammatory biomarkers, including C-reactive protein and the neutrophil-to-lymphocyte ratio, were also determined. After adjusting for confounders, the decreased B lymphocyte count (p = 0.021) and C3 and C4 levels (both p < 0.001) and the increased monocyte count (p = 0.009) and CD8+ T lymphocyte proportion (p = 0.054) were associated with living in the polluted area. Significant differences in the C4 and C3 levels between the areas were only seen in male schoolchildren and in schoolchildren without passive smoking exposure (P_interaction = 0.036 and 0.042, respectively). The alterations in immune biomarkers suggested that air pollution-induced immunotoxic effects and relevant adaptive responses were simultaneously present in schoolchildren exposed to a higher level of air pollution. Future studies investigating the temporal patterns of these biomarkers among children are warranted.

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.

Cardiovascular endothelial inflammation by chronic coexposure to lead (Pb) and polycyclic aromatic hydrocarbons from preschool children in an e-waste recycling area

Lead (Pb) and polycyclic aromatic hydrocarbon (PAH) exposure is positively associated with cardiovascular disease (CVD), and the possible potential mechanism may be caused by damage to the endothelium by modulation of inflammatory processes. No comprehensive research shows co-exposure of Pb and PAH on cardiovascular endothelial inflammation in electronic waste (e-waste) exposed populations. Given this, the aim of this study is to provide evidence for a relationship between Pb and PAH co-exposure and cardiovascular endothelial inflammation, in an e-waste-exposed population, to delineate the link between a potential mechanism for CVD and environmental exposure. We recruited 203 preschool children (3-7 years) were enrolled from Guiyu (e-waste-exposed group, n = 105) and Haojiang (reference group, n = 98). Blood Pb levels and urinary PAH metabolites were measured. Percentages of T cells, CD4⁺ T cells and CD8⁺ T cells, complete blood counts, endothelial inflammation biomarker (serum S100A8/A9), and other inflammatory biomarkers [serum interleukin (IL)-6, IL-12p70, gamma interferon-inducible protein 10 (IP-10)] levels were evaluated. Blood Pb, total urinary hydroxylated PAH (ΣOHPAH), total hydroxynaphthalene (ΣOHNap) and total hydroxyfluorene (ΣOHFlu) levels, S100A8/A9, IL-6, IL-12p70 and IP-10 concentrations, absolute counts of monocytes, neutrophils, and leukocytes, as well as CD4⁺ T cell percentages were significantly higher in exposed children. Elevated blood Pb, urinary 2-hydroxynaphthalene (2-OHNap) and ΣOHFlu levels were associated with higher levels of IL-6, IL-12p70, IP-10, CD4⁺ T cell percentages, neutrophil and monocyte counts. Mediator models indicated that neutrophils exert the significant mediation effect on the relationship between blood Pb levels and S100A8/A9. IL-6 exerts a significant mediation effect on the relationship between blood Pb levels and IP-10, as well as the relationship between urinary ΣOHFlu levels and IP-10. Our results indicate that children with elevated exposure levels of Pb and PAHs have exacerbated vascular endothelial inflammation, which may indicate future CVD risk in e-waste recycling areas.

Air pollution and Autism in Denmark

Supplemental Digital Content is available in the text.

Background:

Previous autism spectrum disorder (ASD) and air pollution studies focused on pregnancy exposures, but another vulnerable period is immediate postnatally. Here, we examined early life exposures to air pollution from the pre- to the postnatal period and ASD/ASD subtypes in the Danish population.

Methods:

With Danish registers, we conducted a nationwide case–control study of 15,387 children with ASD born 1989–2013 and 68,139 population controls matched by birth year and sex identified from the birth registry. We generated air dispersion geographic information system (AirGIS) model estimates for nitrogen dioxide (NO₂), sulfur dioxide (SO₂), particulate matter 2.5 (PM_2.5), and particulate matter 10 (PM₁₀) at mothers’ home from 9 months before to 9 months after pregnancy and calculated odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for parental age, neighborhood socioeconomic indicators, and maternal smoking using conditional logistic regression.

Results:

In models that included all exposure periods, we estimated adjusted ORs for ASD per interquartile range (IQR) increase for 9 months after pregnancy with NO₂ of 1.08 (95% CI = 1.01, 1.15) and with PM_2.5 of 1.06 (95% CI = 1.01, 1.11); associations were smaller for PM₁₀ (1.04; 95% CI = 1.00, 1.09) and strongest for SO₂ (1.21; 95% CI = 1.13, 1.29). Also, associations for pollutants were stronger in more recent years (2000–2013) and in larger cities compared with provincial towns/rural counties. For particles and NO₂, associations were only specific to autism and Asperger diagnoses.

Conclusions:

Our data suggest that air pollutant exposure in early infancy but not during pregnancy increases the risk of being diagnosed with autism and Asperger among children born in Denmark.

Response of cord blood cells to environmental, hereditary and perinatal factors: A prospective birth cohort study

Background

Many studies investigating the impact of individual risk factors on cord blood immune cell counts may be biased given that cord blood composition is influenced by a multitude of factors. The aim of this study was to comprehensively investigate the relative impact of environmental, hereditary and perinatal factors on cord blood cells.

Methods

In 295 neonates from the prospective Basel-Bern Infant Lung Development Cohort, we performed complete blood counts and fluorescence-activated cell sorting scans of umbilical cord blood. The associations between risk factors and cord blood cells were assessed using multivariable linear regressions.

Results

The multivariable regression analysis showed that an increase per 10μg/m³ of the average nitrogen dioxide 14 days before birth was associated with a decrease in leukocyte (6.7%, 95% CI:-12.1,-1.0) and monocyte counts (11.6%, 95% CI:-19.6,-2.8). Maternal smoking during pregnancy was associated with significantly lower cord blood cell counts in multiple cell populations. Moreover, we observed sex differences regarding eosinophilic granulocytes and plasmacytoid dendritic cells. Finally, significantly increased numbers of cord blood cells were observed in infants exposed to perinatal stress. Cesarean section seems to play a significant role in Th1/Th2 balance.

Conclusions

Our results suggest that all three: environmental, hereditary and perinatal factors play a significant role in the composition of cord blood cells at birth, and it is important to adjust for all of these factors in cord blood studies. In particular, perinatal circumstances seem to influence immune balance, which could have far reaching consequences in the development of immune mediated diseases.

Health effects of a forest environment on natural killer cells in humans: an observational pilot study

Health effect assessments based on natural killer (NK) cells are an important emerging area of human health. We recruited 90 forest staff members in Xitou, Taiwan and 110 urban staff members in Taipei to investigate the health effects of forest environment exposure on NK cells (CD3⁻/CD56⁺) and activating NK cells (CD3⁻/CD56⁺/CD69⁺) in humans. We also invited 11 middle-aged volunteers in a pilot study to participate in a five-day/four-night forest trip to Xitou forest to investigate the health effects of a forest trip on NK cells and activating NK cells. Results showed that NK cells were higher in the forest group (19.5 ± 9.1%) than in the urban group (16.4 ± 8.4%). In particular, the percentage of NK cells was significantly higher in the forest group than in the urban group among the subgroups of male, a higher body mass index (≥ 25 kg/m²), without hypertension, lower high-sensitivity C-reactive protein, hyperglycemia, without smoking habit, and with tea drinking habit. After the five-day trip in Xitou forest, the percentage of activating NK cells of the invited participants from Taipei increased significantly after the trip to Xitou forest (0.83 ± 0.39% vs. 1.72 ± 0.1%). The percentage of activating NK cells was 1.13 ± 0.43%, which was higher than the baseline value of 0.77 ± 0.38% before the forest trip among the seven subjects who participated in the follow-up study four days after returning to Taipei. This study suggests that exposure to forest environments might enhance the immune response of NK cells and activating NK cells in humans.

The Influence of Quercetin on Maternal Immunity, Oxidative Stress, and Inflammation in Mice with Exposure of Fine Particulate Matter during Gestation

The objective is to investigate the influence of PM2.5 exposure on peripheral blood lymphocyte subsets in pregnant mice and the antagonism of quercetin on adverse effects induced by PM2.5 exposure. Pregnant mice were randomly divided into control group, PM2.5 model group and 3 quercetin intervention groups. Dams in all groups except the control group were exposed to PM2.5 suspension by intratracheal instillation on gestational day (GD) 3, 6, 9, 12 and 15. Meanwhile, each dam was given 0.15% carboxymethylcellulose sodium (CMCS) (control group & PM2.5 model group) and different doses of quercetin (quercetin intervention groups) by gavage once a day from GD0 to GD17. The percentage of lymphocyte subsets, Biomarkers of systemic inflammation injuries (IL-2, IL-6, IL-8 & TNF-α) and oxidative stress indicators (CAT, GSH & HO-1) in peripheral blood of the dams were analyzed. The number of T cells increased, accompanied by increased level of IL-2, IL-6, IL-8 and HO-1 due to PM2.5 exposure. Less CD4+ and CD8+ T cells were counted in 100 mg/kg quercetin intervention group, compared with PM2.5 model group. Quercetin may inhibit cytokine production, especially in IL-6 and IL-8 and may upgrade the level of HO-1. Our findings indicate that PM2.5 could significantly influence the distribution of T-lymphocyte subsets, activate inflammatory reaction and elevate oxidative stress level in peripheral blood of pregnant mice. Certain dose of quercetin administration during pregnancy may protect the dams against the adverse effects through various ways.

Maternal exposure to ozone and PM2.5 and the prevalence of orofacial clefts in four U.S. states

BACKGROUND

While there is some evidence that maternal exposure to ambient air pollution is associated with orofacial clefts in offspring, the epidemiologic studies have been largely equivocal. We evaluated whether maternal exposure to elevated county-level ambient fine particulate matter with aerodynamic diameter ≤2.5µm (PM_2.5) and ozone during early gestation was associated with a higher prevalence of orofacial clefts.

METHODS

Birth data consisting of 4.7 million births from 2001 to 2007 were obtained from National Birth Defects Prevention Network for four states - Arizona, Florida, New York (excluding New York City), and Texas. The air pollution exposure assessment for gestational weeks 5-10 was based on county-level average concentrations of PM_2.5 and ozone data generated using a Bayesian fusion model available through CDC's Environmental Public Health Tracking Network. Two outcomes were analyzed separately: cleft lip with or without cleft palate, cleft palate alone. In logistic regression analyses, we adjusted for factors that were suspected confounders or modifiers of the association between the prevalence of orofacial clefts and air pollution, i.e., infant sex, race-ethnicity, maternal education, smoking status during pregnancy, whether this was mother's first baby, maternal age.

RESULTS

Each 10µg/m³ increase in PM_2.5 concentration was significantly associated with cleft palate alone (OR =1.43, 95% CI: 1.11-1.86). There was no significant association between PM_2.5 concentration and cleft lip with or without cleft palate. No associations were observed between ozone exposure and the two outcomes of orofacial clefts.

CONCLUSIONS

Our study suggests that PM_2.5 significantly increased the risk of cleft palate alone, but did not change the incidence of cleft lip with or without palate. Ozone levels did not correlate with incidence of orofacial clefts.

Air pollution during pregnancy and lung development in the child

Air pollution exposure has increased extensively in recent years and there is considerable evidence that exposure to particulate matter can lead to adverse respiratory outcomes. The health impacts of exposure to air pollution during the prenatal period is especially concerning as it can impair organogenesis and organ development, which can lead to long-term complications. Exposure to air pollution during pregnancy affects respiratory health in different ways. Lung development might be impaired by air pollution indirectly by causing lower birth weight, premature birth or disturbed development of the immune system. Exposure to air pollution during pregnancy has also been linked to decreased lung function in infancy and childhood, increased respiratory symptoms, and the development of childhood asthma. In addition, impaired lung development contributes to infant mortality. The mechanisms of how prenatal air pollution affects the lungs are not fully understood, but likely involve interplay of environmental and epigenetic effects. The current epidemiological evidence on the effect of air pollution during pregnancy on lung function and children's respiratory health is summarized in this review. While evidence for the adverse effects of prenatal air pollution on lung development and health continue to mount, rigorous actions must be taken to reduce air pollution exposure and thus long-term respiratory morbidity and mortality.

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.

Effects of Developmental Activation of the Aryl Hydrocarbon Receptor by 2,3,7,8-Tetrachlorodibenzo-p-dioxin on Long-term Self-renewal of Murine Hematopoietic Stem Cells

BACKGROUND

Human epidemiological and animal studies suggest that developmental exposure to contaminants that activate the aryl hydrocarbon receptor (AHR) lead to suppression of immune system function throughout life. The persistence of immune deficiency throughout life suggests that the cellular target of AHR activation is a fetal hematopoietic progenitor or stem cell.

OBJECTIVES

The aim of this study was to identify the effects of transplacental exposure to an AHR agonist on long-term self-renewal of fetal hematopoietic stem cells.

METHODS

Pregnant C57BL/6 or AHR+/- mice were exposed to the AHR agonist, 2,3,7,8-tetra-​chlorodibenzo-p-dioxin (TCDD). On day 14 of gestation, hematopoietic progenitors from wild-type or AHR-deficient fetuses were placed into in vitro T-lymphocyte differentiation cultures to identify the effects of transplacental TCDD on AHR activation in the fetus. We next analyzed the fetal hematopoietic progenitor cells for changes in reactive oxygen species (ROS). Finally, hematopoietic progenitors from fetuses exposed transplacentally to TCDD were mixed 1:1 with cells from congenic controls and used to reconstitute lethally irradiated recipients for analysis of long-term self-renewal potential.

RESULTS

Our findings suggested that the effects of TCDD on the developing hematopoietic system were mediated by direct AHR activation in the fetus. Furthermore, developmental AHR activation by TCDD increased ROS in the fetal hematopoietic stem cells, and the elevated ROS was associated with a reduced capacity of the TCDD-exposed fetal cells to compete with control cells in a mixed competitive irradiation/reconstitution assay.

CONCLUSIONS

Our findings indicate that AHR activation by TCDD in the fetus during pregnancy leads to impairment of long-term self-renewal of hematopoietic stem cells.

CITATION

Laiosa MD, Tate ER, Ahrenhoerster LS, Chen Y, Wang D. 2016. Effects of developmental activation of the aryl hydrocarbon receptor by 2,3,7,8-tetrachlorodibenzo-p-dioxin on long-term self-renewal of murine hematopoietic stem cells. Environ Health Perspect 124:957-965; http://dx.doi.org/10.1289/ehp.1509820.

Air pollution modelling for birth cohorts: a time-space regression model

BACKGROUND

To investigate air pollution effects during pregnancy or in the first weeks of life, models are needed that capture both the spatial and temporal variability of air pollution exposures.

METHODS

We developed a time-space exposure model for ambient NO2 concentrations in Bern, Switzerland. We used NO2 data from passive monitoring conducted between 1998 and 2009: 101 rural sites (24,499 biweekly measurements) and 45 urban sites (4350 monthly measurements). We evaluated spatial predictors (land use; roads; traffic; population; annual NO2 from a dispersion model) and temporal predictors (meteorological conditions; NO2 from continuous monitoring station). Separate rural and urban models were developed by multivariable regression techniques. We performed ten-fold internal cross-validation, and an external validation using 57 NO2 passive measurements obtained at study participant's homes.

RESULTS

Traffic related explanatory variables and fixed site NO2 measurements were the most relevant predictors in both models. The coefficient of determination (R(2)) for the log transformed models were 0.63 (rural) and 0.54 (urban); cross-validation R(2)s were unchanged indicating robust coefficient estimates. External validation showed R(2)s of 0.54 (rural) and 0.67 (urban).

CONCLUSIONS

This approach is suitable for air pollution exposure prediction in epidemiologic research with time-vulnerable health effects such as those occurring during pregnancy or in the first weeks of life.

The relationship of exposure to air pollutants in pregnancy with surrogate markers of endothelial dysfunction in umbilical cord

BACKGROUND

This study aims to investigate the association of exposure to ambient air pollution during pregnancy with cord blood concentrations of surrogate markers of endothelial dysfunction.

METHODS

This population-based cohort was conducted from March 2014 to March 2015 among 250 mother-neonate pairs in urban areas of Isfahan, the second large and air-polluted city in Iran. We analyzed the association between the ambient carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), particular matter 10 (PM10), and air quality index (AQI) with cord blood levels of endothelin-1, vascular adhesion molecule (VCAM), and intercellular adhesion molecule (ICAM). Multiple regression analysis was conducted after adjustment for potential confounding factors and covariates. The regression coefficient (beta), standard error of the estimate (SE), and 95% confidence intervals for each regression coefficient (95% CI) are reported.

RESULTS

Data of 233 mother-neonate pairs were complete, and included in the analysis. Multiple regression analyses showed that AQI, CO and O3 had significant correlation with cord blood ICAM-1 [Beta (SE), 95%CI: 2.93 (0.72), 1.33,5.54; 2.28(1.44), 1.56,5.12; and 2.02(0.01), 1.03,2.04, respectively] as well as with VCAM-1 [2.78(0.91), 1.69,4.57; 2.47(1.47), 1.43,5.37; and 2.01(0.01),1.07,2.04, respectively]. AQI, PM10, and SO2 were significantly associated with Endothelin-1 concentrations [Beta (SE), 95%CI: 10.16(5.08),7.61,14.28; 9.70(3.46), 2.88,16.52; and 1.07(0.02), 1.03,2.11, respectively].

CONCLUSIONS

The significant associations of air pollutants with markers of endothelial dysfunction during fetal period may provide another evidence on the adverse health effects of air pollutants on early stages of atherosclerosis from fetal period. Our findings underscore the importance of considering environmental factors in primordial prevention of chronic diseases.

Chemical composition modulates the adverse effects of particles on the mucociliary epithelium

OBJECTIVE

We compared the adverse effects of two types of real ambient particles; i.e., total suspended particles from an electrostatic precipitator of a steel mill and fine air particles from an urban ambient particulate matter of 2.5 µm, on mucociliary clearance.

METHOD

Mucociliary function was quantified by mucociliary transport, ciliary beating frequency and the amount of acid and neutral mucous in epithelial cells through morphometry of frog palate preparations. The palates were immersed in one of the following solutions: total suspended particles (0.1 mg/mL), particulate matter 2.5 µm 0.1 mg/mL (PM0.1) or 3.0 mg/mL (PM3.0) and amphibian Ringer's solution (control). Particle chemical compositions were determined by X-ray fluorescence and gas chromatography/mass spectrometry.

RESULTS

Exposure to total suspended particles and PM3.0 decreased mucociliary transport. Ciliary beating frequency was diminished by total suspended particles at all times during exposure, while particulate matter of 2.5 µm did not elicit changes. Particulate matter of 2.5 µm reduced epithelial mucous and epithelium thickness, while total suspended particles behaved similarly to the control group. Total suspended particles exhibited a predominance of Fe and no organic compounds, while the particulate matter 2.5 µm contained predominant amounts of S, Fe, Si and, to a lesser extent, Cu, Ni, V, Zn and organic compounds.

CONCLUSION

Our results showed that different compositions of particles induced different airway epithelial responses, emphasizing that knowledge of their individual characteristics may help to establish policies aimed at controlling air pollution.

Influences of Environmental Chemicals on Atopic Dermatitis

Atopic dermatitis is a chronic inflammatory skin condition including severe pruritus, xerosis, visible eczematous skin lesions that mainly begin early in life. Atopic dermatitis exerts a profound impact on the quality of life of patients and their families. The estimated lifetime prevalence of atopic dermatitis has increased 2~3 fold during over the past 30 years, especially in urban areas in industrialized countries, emphasizing the importance of life-style and environment in the pathogenesis of atopic diseases. While the interplay of individual genetic predisposition and environmental factors contribute to the development of atopic dermatitis, the recent increase in the prevalence of atopic dermatitis might be attributed to increased exposure to various environmental factors rather than alterations in human genome. In recent decades, there has been an increasing exposure to chemicals from a variety of sources. In this study, the effects of various environmental chemicals we face in everyday life - air pollutants, contact allergens and skin irritants, ingredients in cosmetics and personal care products, and food additives - on the prevalence and severity of atopic dermatitis are reviewed.

Comparison of child morbidity in regions of Ostrava, Czech Republic, with different degrees of pollution: a retrospective cohort study

BACKGROUND

To confirm or refute the hypothesis that the morbidity of children (since birth to age 5) born and living in the heavily polluted (PM10, benzo[a]pyrene) eastern part of Ostrava, Czech Republic, was higher than the morbidity of children living in other parts of the city.

METHODS

Ten pediatricians in 5 districts of Ostrava abstracted the medical records of 1878 children born in 2001-2004 to list all illnesses of each child in ICD-10 codes. The children were divided into four groups according to their residence at birth and thereafter. Most of the children in the eastern area were living in the city district Radvanice and Bartovice.

RESULTS

We report on the incidence of acute illnesses in 1535 children of Czech ethnicity in the first 5 years of life. The most frequent acute illnesses (over 45% of all diagnoses) were upper respiratory infections (URI: J00-J02, J06). In the first year of life, the incidence of URI in 183 children in the eastern area - 372 illnesses/100 children/year - was more than twice as high as in the other 3 areas with a total number of 1352 children. From birth to the age of 5 years, the incidences of pneumonia, tonsillitis, viral infections (ICD-10 code B34) and intestinal infectious diseases were also several times higher in children living in the eastern part of Ostrava. The lowest morbidity was found in children living in the less polluted western part of the city.

CONCLUSIONS

The children born and living in the eastern part of the city of Ostrava had from birth through 5 years significantly higher incidence rates of acute illnesses than children in other parts of Ostrava. They also had a higher prevalence of wheezing, atopic dermatitis and allergic rhinitis.