Immunological alterations in sera of persons living in areas with different air pollution

Long-term exposure to ambient air pollution and incident gout: A prospective cohort study in the UK Biobank

Gout is a chronic disorder characterized by the accumulation of uric acid in the body, leading to recurrent episodes of joint inflammation and pain. There remains a lack of studies investigating the association between long-term exposure to ambient air pollution and the incidence of gout. We conducted this prospective cohort study involving participants aged 38-70 from the UK Biobank who were enrolled in 2006-2010 and followed until 2023. Baseline residential concentrations of fine particulate matter (PM2.5), inhalable particulate matter (PM10), nitrogen dioxide (NO2) and nitrogen oxides (NOx) were predicted using land-use regression models. Cox proportional hazards models were employed to examine the relationship between air pollution and incident gout events. A total of 443,587 individuals were included in the analyses and a total of 6589 incident gout cases were identified over a follow-up of 6,130,439 person-years. There were significant associations between higher levels of air pollution and an increased incidence risk of gout. Higher risk of incident gout was associated with each interquartile range increase in concentrations of PM2.5 (hazard ratio:1.05, 95% confidence intervals: 1.02-1.09), PM10 (1.04, 1.00-1.07), NO2 (1.08, 1.05-1.12) and NOx (1.04, 1.02-1.07). The magnitude of associations was larger at higher concentrations. The association was more prominent among older adults, smokers, and individuals with lower and moderate physical activity. This prospective cohort study provides novel and compelling evidence of increased risk of incident gout associated with long-term air pollution exposures.

Activation of the Complement System on Human Endothelial Cells by Urban Particulate Matter Triggers Inflammation-Related Protein Production

Exposure to particulate matter (PM) is becoming a major global health issue. The amount and time of exposure to PM are known to be closely associated with cardiovascular diseases. However, the mechanism through which PM affects the vascular system is still not clear. Endothelial cells line the interior surface of blood vessels and actively interact with plasma proteins, including the complement system. Unregulated complement activation caused by invaders, such as pollutants, may promote endothelial inflammation. In the present study, we sought to investigate whether urban PM (UPM) acts on the endothelial environment via the complement system. UPM-treated human endothelial cells with normal human serum showed the deposition of membrane attack complexes (MACs) on the cell surface via the alternative pathway of the complement system. Despite the formation of MACs, cell death was not observed, and cell proliferation was increased in UPM-mediated complement activation. Furthermore, complement activation on endothelial cells stimulated the production of inflammation-related proteins. Our results revealed that UPM could activate the complement system in human endothelial cells and that complement activation regulated inflammatory reaction in microenvironment. These findings provide clues with regard to the role of the complement system in pathophysiologic events of vascular disease elicited by air pollution.

Associations of ambient fine particulate matter and its constituents with serum complement C3 in a panel study of older adults in China

Epidemiological studies have demonstrated association between the total mass of fine particulate matter (PM_2.5) exposures and inflammation. There are few studies exploring the associations between PM_2.5 constituents and the biomarkers of inflammation in older adults and the underlying biological mechanisms are not exact. In this study, we examined the associations between PM_2.5 and its constituents (organic carbon (OC), elemental carbon (EC), total carbon (TC), polycyclic aromatic hydrocarbons (PAHs) and complement three factor (C3), an important biomarker of inflammation in a repeated panel of 175 older adults in Beijing, China. We have constructed three different linear mixed effect models (single-pollutant model, constituent-PM_2.5 joint model, and constituent-residual model) to evaluate the association of PM_2.5 and its constituents and complement C3, controlling for concentration of high sensitive C-reactive protein (hs-CRP), day of week, mean temperature, relative humidity, location and potential individual confounders. We found robust positive associations of OC, EC, TC, PAHs and PM_2.5 mass concentration with complement C3 at different lag patterns. The cumulative effects of pollutants increased across average of 2-5 days. Individuals aged 65 and above, or with diabetes, or BMI ≥30, or with no-cardiopathy, or with hypertension also exhibited positive associations between PM_2.5 and complement C3. The results revealed that short-term exposure to PM_2.5 and its constituents could result in a significant increase in serum level of complement C3. These findings suggested a possible involvement of complement C3 in the effect of PM_2.5 on inflammatory reaction.

Exposure to ambient ultrafine particulate matter alters the expression of genes in primary human neurons

Exposure to ambient particulate matter (PM) has been associated with the onset of neurodevelopmental and neurodegenerative disorders, but the mechanism of toxicity remains unclear. To gain insight into this neurotoxicity, this study sought to examine global gene expression changes caused by exposure to ambient ultrafine PM. Microarray analysis was performed on primary human neurons derived from fetal brain tissue after a 24h exposure to 20μg/mL of ambient ultrafine particles. We found a majority of the changes in noncoding RNAs, which are involved in epigenetic regulation of gene expression, and thereby could impact the expression of several other protein coding gene targets. Although neurons from biologically different lot numbers were used, we found a significant increase in the expression of metallothionein 1A and 1F in all samples after exposure to particulate matter as confirmed by quantitative PCR. These metallothionein 1 proteins are responsible for neuroprotection after exposure to environmental insult but prolonged induction can be toxic. Epidemiological studies have reported that in utero exposure to ultrafine PM not only leads to neurodevelopmental and behavioral abnormalities, but may also predispose the progeny to neurodegenerative disease later in life by genetic imprinting. Our results pinpoint some of the PM-induced genetic changes that may underlie these findings.

Effects of air pollution on human health and practical measures for prevention in Iran

Air pollution is a major concern of new civilized world, which has a serious toxicological impact on human health and the environment. It has a number of different emission sources, but motor vehicles and industrial processes contribute the major part of air pollution. According to the World Health Organization, six major air pollutants include particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Long and short term exposure to air suspended toxicants has a different toxicological impact on human including respiratory and cardiovascular diseases, neuropsychiatric complications, the eyes irritation, skin diseases, and long-term chronic diseases such as cancer. Several reports have revealed the direct association between exposure to the poor air quality and increasing rate of morbidity and mortality mostly due to cardiovascular and respiratory diseases. Air pollution is considered as the major environmental risk factor in the incidence and progression of some diseases such as asthma, lung cancer, ventricular hypertrophy, Alzheimer's and Parkinson's diseases, psychological complications, autism, retinopathy, fetal growth, and low birth weight. In this review article, we aimed to discuss toxicology of major air pollutants, sources of emission, and their impact on human health. We have also proposed practical measures to reduce air pollution in Iran.

Proinflammatory and anti-inflammatory cytokines in adolescents from Southeast Bulgarian cities with different levels of air pollution

Epidemiological studies demonstrated that the exposure of different air pollutants including particulate matter (PM) has been related to adverse effect on immune system. Current study was designed to investigate cytokines in blood plasma of adolescent persons continuously exposed to different degrees of ambient air pollutions. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), IL-12p40, and IL-10 were chosen as cytokines of proinflammatory and anti-inflammatory immune response. The peripheral venous blood was taken from adolescents living in the cities of Stara Zagora region, Southeast Bulgaria, that is, in Stara Zagora, Kazanlak, and Chirpan. The quantity of cytokines in plasma samples was determined by enzyme-linked immunosorbent assay. Results demonstrated that youths living in Stara Zagora showed significantly smaller quantity of TNF-α, compared with adolescents from Kazanlak and Chirpan. Moreover, adolescents living in Stara Zagora showed significantly higher quantity of IL-10 than students from Kazanlak and Chirpan. Analysis of the data of air quality gives reason to assert that PM10 and PM2.5 have been the main atmospheric pollutants around the monitoring points. The complex air quality assessment based on these criteria determined that the highest air pollution was in the city of Stara Zagora, followed by Chirpan and the relatively unpolluted town was Kazanlak. We concluded that air pollutants, mostly PM2.5, can modulate cytokine production and can change the balance between proinflammatory TNF-α and anti-inflammatory IL-10 production. Increased levels of IL-10 combined with decreased level of TNF-α in adolescents living in Stara Zagora can serve as a biomarker for suppression of T helper 1 (Th1) cell-mediated immunity and exacerbation of Th2 humoral immune response and could be a prerequisite for the development of allergic and autoimmune diseases.

Air pollution as a potential contributor to the 'epidemic' of autoimmune disease

There has been remarkable progress over the past 20 years in pushing forward our understanding of many facets of autoimmune disease. Indeed, knowledge of the genetic basis of autoimmunity and the molecular and cellular pathways involved in its pathogenesis has reached an unprecedented level. Yet this knowledge has not served to prevent autoimmune disease nor to curtail the dramatic rise in its incidence over the same interval. Population-level genetic changes cannot explain this trend; thus, environmental factors are strongly implicated. Among the possible environmental contributors to autoimmune disease, air pollution exposure has received very little attention. Although there is only a small amount of published data directly examining a possible causal relationship between air pollution exposure and autoimmunity, data from related fields suggests that it could facilitate autoimmunity as well. If correct, this hypothesis could prove to have sizeable public health implications.

Maternal exposure to ambient air pollutants and risk of congenital anomalies

Studies have suggested an association between maternal exposure to ambient air pollution and risk of congenital anomaly. The aim of this study is to investigate the association between exposure to black smoke (BS; particulate matter with aerodynamic diameter <4 microg/m(3)) and sulphur dioxide (SO(2)) during the first trimester of pregnancy and risk of congenital anomalies. We used a case-control study design among deliveries to mothers resident in the UK Northern health region during 1985-1990. Case data were ascertained from the population-based Northern Congenital Abnormality Survey and control data from national data on all births. Data on BS and SO(2) from ambient air monitoring stations were used to average the total pollutant exposure during the first trimester of pregnancy over the daily readings from all monitors within 10 km of the mother's residence. Logistic regression models estimated the association via odds ratios. A significant but weak positive association was found between nervous system anomalies and BS (OR=1.10 per increase of 1000 microg/m(3) total BS; 95% CI: 1.03, 1.18), but not with other anomaly subtypes. For SO(2), a significant negative association was found with congenital heart disease combined and patent ductus arteriosus: OR significantly <1 for all quartiles relative to the first quartile. The relationship between SO(2) levels and other anomaly subtypes was less clear cut: there were either no significant associations or a suggestion of a U-shaped relationship (OR significantly <1 for moderate compared to lowest levels, but not with high SO(2) levels). Overall, maternal exposure to BS and SO(2) in the Northern region had limited impact on congenital anomaly risk. Studies with detailed exposure assessment are needed to further investigate this relationship.

The pharmacology of particulate matter air pollution-induced cardiovascular dysfunction

Since the London fog of 1952, in which more than 4000 people were killed in 4 days, the combined efforts of scientists from several disciplines, including those from the environmental health, clinical and biomedical disciplines, have raised serious concerns about the impact of air pollutants on human health. These environmental pollutants are rapidly being recognized as important and independent risk factors for several diseases such as asthma, chronic obstructive pulmonary disease, lung cancer, atherosclerosis, ischemic heart disease and stroke. Although the relative effects of particulate matter air pollution (aerodynamic diameter <10 microm, or PM(10)) are greater for respiratory than for cardiovascular deaths, the number of deaths attributable to PM(10) is much larger for cardiovascular than for respiratory reasons due to the higher prevalence of cardiovascular disease in the general population. This review summarizes current understanding of the mechanisms underlying the associations between PM(10) exposure and cardiovascular morbidity and mortality.

Pyrethroids used indoors--immune status of humans exposed to pyrethroids following a pest control operation--a one year follow-up study

A multiparametric analysis of immune components was performed in blood and serum of 61 voluntary persons before and after (1 day, 3 days, 4-6 months, 10-12 months) a professional pest control operation (PCO) using pyrethroids. Following parameters were included in the study (1) immunological parameters of the humoral defence, i.e. immunoglobulins of the classes A, G, M and E, complement components C3c and C4, acute phase proteins such as acid alpha 1-glycoprotein, haptoglobin, C-reactive protein; (2) mediators and receptors of immunity, i.e. neopterin, soluble interleukin-2 receptor (sIL-2R), soluble interleukin-6 receptor (sIL-6R), soluble tumor necrosis factor receptor (sTNF RII); (3) immunological markers of the cellular defence, i.e. white blood cell counts and lymphocyte (sub)populations such as total lymphocytes (CD2), mature lymphocytes (CD3), T-helper/inducer cells (CD4), T-suppressor/cytotoxic cells (CD8), B-cells (CD20), natural killer cells (CD56), as well as the ratio of CD4/CD8. The medians of all investigated immune components found before and for all time intervals after pyrethroid application were within the reference interval with respect to the total collective. Within this physiological range the investigated parameters showed a trend to lower values predominantly during the early phase (1 and 3 days) after PCO, partially being significant. Significant decreases were no more present in the late phase (6 to 12 month) after PCO indicating reversibility. Atopics did not differ in the immune response after PCO as compared to non-atopics. Obtained results suggest a modulation of immune components after a correct performed PCO within the physiological range towards lower values during the first days. However these immune changes are considered to be subtle and underlying compensatory mechanisms of immunoregulation.

Complement factor 3 mediates particulate matter-induced airway hyperresponsiveness

Epidemiologic studies have suggested that exposure to airborne particulate matter (PM) can exacerbate allergic airway responses; however, the mechanism(s) are not well understood. We and others have recently shown that development of airway hyperresponsiveness (AHR) may be a complement-mediated process. In the present study, we examined the role of complement factor 3 (C3) in the development of PM-induced AHR and airway inflammation by comparing responses between C3-deficient (C3(-/-)) and wild-type mice. Mice were exposed to 0.5 mg of ambient particulate collected in urban Baltimore. Forty-eight hours later, airway responsiveness to intravenous acetylcholine was assessed and bronchoalveolar lavage was conducted. PM exposure of wild-type mice resulted in significant increases in AHR, whereas it did not significantly increase airway reactivity in C3(-/-) mice. Interestingly, PM induced similar inflammatory responses in both wild-type and C3(-/-) mice. Immunohistochemical staining demonstrated marked C3 deposition in the airway epithelium and connective tissue of wild-type mice after PM exposure. These results suggest that exposure to PM may induce AHR through activation of complement factor 3 in the airways.

Air pollution and distributions of lymphocyte immunophenotypes in cord and maternal blood at delivery

A cross-sectional study of deliveries in two districts in the Czech Republic, 1994-1996, assessed the relation between air pollution and lymphocyte immunophenotype distributions. Maternal and cord blood samples were assayed by flow cytometry within 24 hours of delivery for 303 deliveries from Teplice, a polluted district, and 215 from Prachatice, a less polluted district. Analyses focused on: CD3(+) T-lymphocytes, CD3(-) CD19(+) B-lymphocytes, and CD3(-) CD16(+)56(+) natural killer (NK) lymphocytes, as well as the subsets CD3(+)CD4(+) ("T-helper") and CD3(+)CD8(+) ("T cytotoxic/suppressor") and the ratio of these two lymphocytes. We collected reproductive, occupational, and life-style information by questionnaire, and abstracted data on labor and delivery from medical records. After adjustment for numerous risk factors in multivariate linear regression models fit for each lymphocyte subset, mothers from Teplice had lower percentages of total T-cells and of CD4(+) cells, and a lower ratio of CD4(+):CD8(+) cells. Cord bloods from Teplice had a higher percentage of NK cells and a less precise lower percentage of T-cells. Stronger differences in maternal lymphocytes were seen when analyses were limited to the central hospital in each district. Heavy air pollution may affect the immune system in pregnant women and/or fetuses, reflecting an acute and/or chronic effect, although unmeasured confounders could also play a role.

Cytokines detectable in saliva of children as appropriate markers of local immunity of the oral cavity--an approach for the use in air pollution studies

The objective of this study was the detection of proinflammatory markers in saliva to be involved in local immunity of the oral cavity. Therefore saliva of 167 schoolchildren aged 8-10 years were investigated for the presence of interleukin-8 (IL-8), tumour necrosis factor alpha (TNF alpha) and soluble tumour necrosis factor receptor type II (sTNFRII). In saliva of schoolchildren sufficient quantities of IL-8 (302.3-4208.6 pg/ml), TNF alpha (0.3-40.6 pg/ml) and sTNFRII (17.6-931.3 pg/ml) were detectable. IL-8, TNF alpha and sTNFRII revealed significant correlations with each other. Results suggest an immunoregulatory mechanism of IL-8, TNF alpha and TNF-receptor to be of special concern in host defence as well as in maintaining homeostasis of local immunity within the oral cavity. Saliva provides an ideal medium for the detection of proinflammatory markers of the oral cavity with respect to mucosal and granulotype origin and may be employed in air pollution epidemiology, especially with regard to children.

Serum complement levels in children in communities with different levels of air pollution in Japan

To investigate the effects of air pollution on human health, we determined serum concentrations of complement components C3c and C4 in 1037 children who lived in 4 communities with different levels of air pollution in Japan. Serum levels of C3c and C4 were higher in children who lived in Osaka, which had a high level of air pollution, than in children who lived in areas of low air pollution. In boys, both C3c and C4 levels were increased significantly as concentrations of air pollution increased in the communities. In girls, however, the relationship was not significant. Serum levels of C3c and C4 did not differ with respect to asthma or wheezing. These findings suggest that serum C3c and C4 levels in children reflect the effects of exposure to air pollutants in urban districts. Boys appeared to be more susceptible to the effects of air pollution than girls.

Immunological parameters in humans exposed to pesticides in the agricultural environment

Immune parameters were examined in 224 sera of non-exposed controls and in 304 sera of pesticide applicators in the agricultural environment. In comparison to the control group pesticide applicators showed significant increased odds ratios for neopterin and soluble tumor necrosis factor receptor (sTNF RII) and a decreased odds ratio for immunoglobulin M. Obtained results indicate an enhanced macrophage activation and an impaired humoral defense. These alterations have been found to correlate with exposure duration in the group of pesticide applicators in agriculture. For subjects who worked in indoor pest control an inverse correlation for sTNF RII with exposure duration was obtained indicating impairment of cell mediated immune function. It can be concluded that exposure to pesticides in the agricultural environment may contribute to modulation of the immune system. Since immune modulating agents can potentially lead to adverse health consequences the involvement of immune biomarkers in pesticide-related health studies seems to be of considerable value for risk assessment studies.