Polychlorinated dibenzo-dioxins and polychlorinated dibenzo-furans exposure and altered lung function: The mediating role of oxidative stress

DNA damage resulting from human endocrine disrupting chemical exposure: Genotoxicity, detection and dietary phytochemical intervention

In recent years, exposure to endocrine disrupting chemicals (EDCs) has posed an increasing threat to human health. EDCs are major risk factors in the occurrence and development of many diseases. Continuous DNA damage triggers severe pathogenic consequences, such as cancer. Beyond their effects on the endocrine system, EDCs genotoxicity is also worthy of attention, owing to the high accessibility and bioavailability of EDCs. This review investigates and summarizes nearly a decade of DNA damage studies on EDC exposure, including DNA damage mechanisms, detection methods, population marker analysis, and the application of dietary phytochemicals. The aims of this review are (1) to systematically summarize the genotoxic effects of environmental EDCs (2) to comprehensively summarize cutting-edge measurement methods, thus providing analytical solutions for studies on EDC exposure; and (3) to highlight critical data on the detoxification and repair effects of dietary phytochemicals. Dietary phytochemicals decrease genotoxicity by playing a major role in the detoxification system, and show potential therapeutic effects on human diseases caused by EDC exposure. This review may support research on environmental toxicology and alternative chemo-prevention for human EDC exposure.

Ambient temperature exposure causes lung function impairment: The evidence from Controlled Temperature Study in Healthy Subjects (CTSHS)

BACKGROUND

The effect of non-optimal ambient temperatures (low and high temperatures) on lung function and the underlying mechanisms remains unclear.

METHODS

Forty-three (20 males, 23 females) healthy non-obese volunteers with an average of 23.9 years participated in the controlled temperature study. All volunteers underwent three temperature exposures in a sequence (moderate [18 °C], low [6 °C], and high [30 °C] temperatures) lasting 12 h with air pollutants controlled. lung function parameters (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV₁], and peak expiratory flow [PEF]) were determined in each exposure. Blood and urine samples were collected after each exposure and assayed for inflammatory markers [C-reactive protein (CRP), procalcitonin (PCT), platelet-lymphocyte ratio (PLR), and neutrophil-lymphocyte ratio (NLR)] and oxidative damage markers [protein carbonylation (PCO), 4-hydroxy-2-nominal-mercapturic acid (HNE-MA), 8-iso-prostaglandin-F_2α (8-isoPGF_2α), and 8-hydroxy-2-deoxyguanosine (8-OHdG)]. Mixed-effects models were constructed to assess the changes of the above indexes under low or high temperatures relative to moderate temperature, and then the repeated measures correlation analyses were performed.

RESULTS

Compared with moderate temperature, a 2.20% and 2.59% net decrease in FVC, FEV₁, and a 5.68% net increase for PEF were observed under low-temperature exposure, while a 1.59% net decrease in FVC and a 7.29% net increase in PEF under high-temperature exposure were found (all P < 0.05). In addition, low temperature elevated inflammatory markers (PCT, PLR, and NLR) and oxidative damage markers (8-isoPGF_2α, 8-OHdG), and high temperature elevated HNE-MA. Repeated measures correlation analyses revealed that PCT (r = -0.33) and NLR (r = -0.31) were negatively correlated with FVC and HNE-MA (r = -0.35) and 8-OHdG (r = -0.31) were negatively correlated with the FEV₁ under low-temperature exposure (all P < 0.05).

CONCLUSION

Non-optimal ambient temperatures exposure alters lung function, inflammation, and oxidative damage. Inflammation and oxidative damage might be involved in low temperature-related lung function reduction.

The Role of CD40, CD86, and Glutathione S-Transferase Omega 1 in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Objective. The aim of the study was to explore the relevance of CD40, CD86, and GSTO1 with the pathogenesis of COPD. Methods. Patients with acute exacerbation of COPD were contrasted with the healthy and nonsmoking ones and smoking but without COPD ones. The changes of CD40, CD86, and GSTO1 in the peripheral blood, collected from different groups, were detected by flow cytometry and western blotting, respectively. Results. Compared with the nonsmoking group and smoking but without the COPD group, the expression of CD40 and CD86 of the patients with COPD increased significantly, but the expression of GSTO1 decreased. CD40 and CD86 were negatively correlated with FEV1%, while GSTO1 was positively correlated with FEV1% and negatively correlated with CD40 and CD86. Conclusion. CD40, CD86, and GSTO1 may play a role in the pathogenesis of COPD, and they are related to the severity of COPD and the degree of changes in the lung function.

Personal PM2.5-bound PAH exposure, oxidative stress and lung function: The associations and mediation effects in healthy young adults

Decreased lung function is an early hazard of respiratory damage from fine particulate matter (PM_2.5) exposure. Limited studies have explored the association between PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) and lung function, but studies at the personal level in healthy young adults are scarce. Here, we assessed personal PM_2.5 and PM_2.5-bound PAH levels in a panel of 45 healthy young adults by a time-weighted model. The aims were to investigate the relationship between personal exposure and lung function by a linear mixed effect model, and to explore the mediating effects of oxidative stress in this association. The results showed that personal exposure to PM_2.5 and PAHs had the greatest negative effect on forced expiratory volume in 1 s (FEV₁), peak expiratory flow rate (PEF) and forced expiratory flow between 25% and 75% vital capacity (FEF_25-75) at lag 3 days. An IQR increase in personal PM_2.5 exposure was associated with a change of 0.35% (95% CI: 0.27%, 0.42%) in FEV₁, 0.39% (95% CI: 0.29%, 0.47%) in PEF and 0.36% (95% CI: 0.27%, 0.45%) in FEF_25-75. An IQR increase in personal PAH exposure was associated with a decrease of 0.63% (95% CI: 0.55%, 0.69%) in FEV₁, 0.69% (95% CI: 0.61%, 0.75%) in PEF and 0.66% (95% CI: 0.57%, 0.72%) in FEF_25-75. Additionally, exposure to PM_2.5 and PAHs resulted in the strongest positive effects on urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F_2α (8-iso-PGF_2α). Of these, 8-OHdG mediated 10.33%, 8.87% and 9.45% of the associations of personal PM_2.5 exposure with FEV₁, PEF and FEF_25-75, respectively. Our results revealed that personal exposure to PM_2.5 and PAHs was associated with lung function decline in healthy young adults, and urinary 8-OHdG mediated the association between personal PM_2.5 and lung function.

Personal PM2.5 exposure and lung function: Potential mediating role of systematic inflammation and oxidative damage in urban adults from the general population

BACKGROUND

Short-term effects of fine particulate matter (PM_2.5) exposure on lung function have been reported. However, few studies have assessed PM_2.5 exposure on the personal level, and the mechanism underlying the effects of PM_2.5 exposure on lung function remains less clear.

OBJECTIVES

To evaluate the association between personal PM_2.5 exposure and lung function alteration in general population and to explore the roles of systematic inflammation and oxidative damage in this association.

METHODS

A total of 7685 lung function tests were completed among 4697 urban adults in Wuhan, China. Plasma C-reactive protein (CRP), urinary 8-iso-prostaglandin-F_2α (8-iso-PGF_2α) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured. Personal PM_2.5 exposure levels were estimated using an estimation model from the actual measurements of individual PM_2.5 levels in 191 participants. Mixed linear models were used to evaluate the association between personal PM_2.5 exposure and lung function. Mediation analyses were conducted to investigate the roles of CRP, 8-iso-PGF_2α and 8-OHdG in above associations.

RESULTS

After adjusting for confounders, each 10 μg/m³ increase in the previous-day personal PM_2.5 exposure was associated with 2.94 mL, 2.02 mL and 16.14 mL/s decreases in forced vital capacity (FVC), forced expiration volume in 1 s (FEV₁) and peak expiratory flow, respectively. The associations were more obvious among never smokers compared with current smokers. Cumulative 7-day exposure to PM_2.5 led to the strongest adverse effects on lung function. Among never smokers with high PM_2.5 exposure levels, a positive relationship was observed between personal PM_2.5 level and urinary 8-iso-PGF_2α, and 8-iso-PGF_2α meditated 4.69% and 12.30% of the association between the 7-day moving PM_2.5 concentration and FVC and FEV₁, respectively. We did not observe a significant positive association between PM_2.5 exposure and plasma CRP or urinary 8-OHdG.

CONCLUSION

Short-term personal exposure to PM_2.5 is associated with reduced pulmonary ventilation function. Urinary 8-iso-PGF_2α partly mediates these associations.

Epidemiologic evidence linking oxidative stress and pulmonary function in healthy populations

Respiratory health in the general population declines regardless of the presence of pulmonary diseases. Oxidative stress has been implicated as one of the mechanisms involved in respiratory dysfunction. This review was to evaluate studies that relate oxidative stress factors with pulmonary function among the general population without prior respiratory illnesses. The search yielded 54 citations. Twenty-one studies qualified for incorporation in this review. Owing to the heterogeneity of the review, studies were discussed based on identified oxidative stress factors responsible for pulmonary dysfunction. Oxidative stress biomarkers, including gene polymorphisms of nuclear factor erythroid 2-related factor 2, heme oxygenase 1, glutathione S transferase, superoxide dismutase, and lipid peroxidation products were involved in lung function decline. In addition, the antioxidant status of individuals in reference to dietary antioxidant intake and exposure to environmental pollutants affected oxidative stress and pulmonary function, as indicated by forced expired volume in one second, forced vital capacity, and forced expiratory flow at 25%–75%_. This review indicated that oxidative stress is implicated in the gradual decline of lung function among the general population, and gene polymorphism along the antioxidant defense line and/or their interaction with air pollutants reduce lung function. Different polymorphic forms among individuals explain why the rate of lung function decline differs among people. Dietary antioxidants have respiratory health benefits in antioxidant gene polymorphic forms. Therefore, the genetic composition of an individual may be considered for monitoring and identifying people at risk of respiratory illnesses.

Aryl Hydrocarbon Receptor and Dioxin-Related Health Hazards-Lessons from Yusho

Poisoning by high concentrations of dioxin and its related compounds manifests variable toxic symptoms such as general malaise, chloracne, hyperpigmentation, sputum and cough, paresthesia or numbness of the extremities, hypertriglyceridemia, perinatal abnormalities, and elevated risks of cancer-related mortality. Such health hazards are observed in patients with Yusho (oil disease in Japanese) who had consumed rice bran oil highly contaminated with 2,3,4,7,8-pentachlorodibenzofuran, polychlorinated biphenyls, and polychlorinated quaterphenyls in 1968. The blood concentrations of these congeners in patients with Yusho remain extremely elevated 50 years after onset. Dioxins exert their toxicity via aryl hydrocarbon receptor (AHR) through the generation of reactive oxygen species (ROS). In this review article, we discuss the pathogenic implication of AHR in dioxin-induced health hazards. We also mention the potential therapeutic use of herbal drugs targeting AHR and ROS in patients with Yusho.

Serum metabolic changes associated with dioxin exposure in a Chinese male cohort

Dioxins, a group of persistent organic pollutants, have been proved to correlate with ranges of diseases by activating the aryl hydrocarbon receptor (AhR). However, previous dioxin toxicity studies primarily focused on the activation of AhR with signaling pathways at gene and protein levels. The investigation of underlying mechanisms at the metabolic level is still necessary. In this study, serum samples of 48 and 47 healthy participants with the highest and lowest dioxin levels based on quartile distribution of the serum dioxin concentrations of 215 male adults were selected for metabolomics analysis by using liquid chromatography coupled with orbitrap high-resolution mass spectrometry to investigate dioxin-related metabolic responses. The identified potential biomarkers included acylcarnitines, fatty acids and derivatives, glycerophospholipids, etc. suggested that metabolic pathways such as fatty acid β-oxidation, essential fatty acid metabolism, arachidonic acid metabolism, glycerophospholipid and sphingolipid metabolism and purine metabolism were disturbed by dioxin exposure. The results indicated that people with high dioxin exposure levels were at the potential health risks of inflammation, liver and cardiovascular diseases. The metabolic findings may help understand the link between dioxin exposure and the diseases.