Investigation of inflammation inducing substances in PM2.5 particles by an elimination method using thermal decomposition

Subchronic exposure to 1,2-naphthoquinone induces adipose tissue inflammation and changes the energy homeostasis of mice, partially due to TNFR1 and TLR4

Air pollution affects energy homeostasis detrimentally. Yet, knowledge of how each isolated pollutant can impact energy metabolism remains incomplete. The present study was designed to investigate the distinct effects of 1,2-naphthoquinone (1,2-NQ) on energy metabolism since this pollutant increases at the same rate as diesel combustion. In particular, we aimed to determine in vivo effects of subchronic exposure to 1,2-NQ on metabolic and inflammatory parameters of wild-type mice (WT) and to explore the involvement of tumor necrosis factor receptor 1 (TNFR1) and toll-like receptor 4 (TLR4) in this process. Males WT, TNFR1KO, and TLR4KO mice at eight weeks of age received 1,2-NQ or vehicle via nebulization five days a week for 17 weeks. In WT mice, 1,2-NQ slightly decreased the body mass compared to vehicle-WT. This effect was likely due to a mild food intake reduction and increased energy expenditure (EE) observed after six weeks of exposure. After nine weeks of exposure, we observed higher fasting blood glucose and impaired glucose tolerance, whereas insulin sensitivity was slightly improved compared to vehicle-WT. After 17 weeks of 1,2-NQ exposure, WT mice displayed an increased percentage of M1 and a decreased (p = 0.057) percentage of M2 macrophages in adipose tissue. The deletion of TNFR1 and TLR4 abolished most of the metabolic impacts caused by 1,2-NQ exposure, except for the EE and insulin sensitivity, which remained high in these mice under 1,2-NQ exposure. Our study demonstrates for the first time that subchronic exposure to 1,2-NQ affects energy metabolism in vivo. Although 1,2-NQ increased EE and slightly reduced feeding and body mass, the WT mice displayed higher inflammation in adipose tissue and impaired fasting blood glucose and glucose tolerance. Thus, in vivo subchronic exposure to 1,2-NQ is harmful, and TNFR1 and TLR4 are partially involved in these outcomes.

Association of the components of ambient fine particulate matter (PM2.5) and chronic kidney disease prevalence in China

Previous research has implicated PM_2.5 as a potential environmental risk factor for CKD, but little is known about the associations between its components and CKD. We conducted a nationwide cross-sectional study using the updated air pollution data in the nationwide population (N = 2,938,653). Using generalized additive models, we assessed the association between long-term exposure to PM_2.5 and its components (i.e., black carbon [BC], organic matter [OM], nitrate [NO₃^-], ammonium [NH₄⁺], sulfate [SO₄^2-]), and CKD prevalence. The air pollution data was estimated using high-resolution and high-quality spatiotemporal datasets of ground-level air pollutants in China. Besides, we adopted a novel quantile-based g-computation approach to assess the effect of a mixture of PM_2.5 constituents on CKD prevalence. The average concentration of PM_2.5 was 78.67 ± 22.5 μg/m³, which far exceeded WHO AQG. In the fully adjusted generalized additive model, at a 10 km × 10 km spatial resolution, the ORs per IQR increase in previous 1-year average PM_2.5 exposures was 1.380 (95%CI: 1.345-1.415), for NH₄⁺ was 1.094 (95%CI: 1.062-1.126), for BC was 1.604 (95%CI: 1.563-1.646), for NO₃^- was 1.094 (95%CI: 1.060-1.130), for SO₄^2- was 1.239 (95%CI: 1.208-1.272), and for the OM was 1.387 (95%CI: 1.354-1.421), respectively. Subgroup analysis showed females, younger, and healthier were more vulnerable to this effect. In the further exploration of the joint effect of PM_2.5 compositions (OR 1.234 [95%CI 1.222-1.246]) per quartile increase in all 5 PM_2.5 components, we found that PM_2.5SO₄^2- contributed the most. These findings provide important evidence for the positive relationship between long-term exposure to PM_2.5 and its chemical constituents and CKD prevalence in a Chinese health check-up population, and identified PM_2.5SO₄^2- has the highest contribution to this relationship. This study provides clinical and public health guidance for reducing specific air particle exposure for those at risk of CKD.

Differential Pattern of Cell Death and ROS Production in Human Airway Epithelial Cells Exposed to Quinones Combined with Heated-PM2.5 and/or Asian Sand Dust

The combined toxicological effects of airborne particulate matter (PM), such as PM2.5, and Asian sand dust (ASD), with surrounding chemicals, particularly quinones, on human airway epithelial cells remain underexplored. In this study, we established an in vitro combination exposure model using 1,2-naphthoquinones (NQ) and 9,10-phenanthroquinones (PQ) along with heated PM (h-PM2.5 and h-ASD) to investigate their potential synergistic effects. The impacts of quinones and heated PM on tetrazolium dye (WST-1) reduction, cell death, and cytokine and reactive oxygen species (ROS) production were examined. Results revealed that exposure to 9,10-PQ with h-PM2.5 and/or h-ASD dose-dependently increased WST-1 reduction at 1 μM compared to the corresponding control while markedly decreasing it at 10 μM. Higher early apoptotic, late apoptotic, or necrotic cell numbers were detected in 9,10-PQ + h-PM2.5 exposure than in 9,10-PQ + h-ASD or 9,10-PQ + h-PM2.5 + h-ASD. Additionally, 1,2-NQ + h-PM2.5 exposure also resulted in an increase in cell death compared to 1,2-NQ + h-ASD and 1,2-NQ + h-PM2.5 + h-ASD. Quinones with or without h-PM2.5, h-ASD, or h-PM2.5 + h-ASD significantly increased ROS production, especially with h-PM2.5. Our findings suggest that quinones, at relatively low concentrations, induce cell death synergistically in the presence of h-PM2.5 rather than h-ASD and h-PM2.5 + h-ASD, partially through the induction of apoptosis with increased ROS generation.

Association of Long-term Ambient Fine Particulate Matter (PM2.5) and Incident CKD: A Prospective Cohort Study in China

RATIONALE & OBJECTIVE

Increasing evidence has linked ambient fine particulate matter (ie, particulate matter no larger than 2.5 μm [PM_2.5]) to chronic kidney disease (CKD), but their association has not been fully elucidated, especially in regions with high levels of PM_2.5 pollution. This study aimed to investigate the long-term association of high PM_2.5 exposure with incident CKD in mainland China.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

72,425 participants (age ≥18 years) without CKD were recruited from 121 counties in Hunan Province, China.

EXPOSURE

Annual mean PM_2.5 concentration at the residence of each participant derived from a long-term, full-coverage, high-resolution (1 × 1 km²), high-quality dataset of ground-level air pollutants in China.

OUTCOMES

Incident CKD during the interval between the baseline examination of each participant (2005-2017) and the end of follow-up through 2018.

ANALYTICAL APPROACH

Cox proportional hazards models were used to estimate the independent association of PM_2.5 with incident CKD and the joint association of PM_2.5 with temperature or humidity on the development of PM_2.5-related CKD. Restricted cubic splines were used to model exposure-response relationships.

RESULTS

Over a median follow-up of 3.79 (IQR, 2.03-5.48) years, a total of 2,188 participants with incident CKD were identified. PM_2.5 exposure was associated with incident CKD with an adjusted hazard ratio of 1.71 (95% CI, 1.58-1.85) per 10-μg/m³ greater long-term exposure. Multiplicative interactions between PM_2.5 and humidity or temperature on incident CKD were detected (all P < 0.001 for interaction), whereas an additive interaction was detected only for humidity (relative risk due to interaction, 3.59 [95% CI, 0.97-6.21]).

LIMITATIONS

Lack of information on participants' activity patterns such as time spent outdoors.

CONCLUSIONS

Greater long-term ambient PM_2.5 pollution is associated with incident CKD in environments with high PM_2.5 exposure. Ambient humidity has a potentially synergetic effect on the association of PM_2.5 with the development of CKD.

PLAIN-LANGUAGE SUMMARY

Exposure to a form of air pollution known as fine particulate matter (ie, particulate matter ≤2.5 μm [PM_2.5]) has been linked to an increased risk of chronic kidney disease (CKD), but little is known about how PM_2.5 affects CKD in regions with extremely high levels of PM_2.5 pollution. This longitudinal cohort study in China investigates the effect of PM_2.5 on the incidence of CKD and whether temperature or humidity interact with PM_2.5. Our findings suggest that long-term exposure to high levels of ambient PM_2.5 significantly increased the risk of CKD in mainland China, especially in terms of cumulative average PM_2.5. The associations of PM_2.5 and incident CKD were greater in high-humidity environments. These findings support the recommendation that reducing PM_2.5 pollution should be a priority to decrease the burden of associated health risks, including CKD.

Role of atmospheric particulate matter exposure in COVID-19 and other health risks in human: A review

Due to intense industrialization and urbanization, air pollution has become a serious global concern as a hazard to human health. Epidemiological studies found that exposure to atmospheric particulate matter (PM) causes severe health problems in human and significant damage to the physiological systems. In recent days, PM exposure could be related as a carrier for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus transmission and Coronavirus disease 2019 (COVID-19) infection. Hence, it is important to understand the adverse effects of PM in human health. This review aims to provide insights on the detrimental effects of PM in various human health problems including respiratory, circulatory, nervous, and immune system along with their possible toxicity mechanisms. Overall, this review highlights the potential relationship of PM with several life-limiting human diseases and their significance for better management strategies.

Long-Term Exposure to Ambient PM2.5 and Increased Risk of CKD Prevalence in China

BACKGROUND

Fine particulate matter (PM_2.5) is an important environmental risk factor for cardiopulmonary diseases. However, the association between PM_2.5 and risk of CKD remains under-recognized, especially in regions with high levels of PM_2.5, such as China.

METHODS

To explore the association between long-term exposure to ambient PM_2.5 and CKD prevalence in China, we used data from the China National Survey of CKD, which included a representative sample of 47,204 adults. We estimated annual exposure to PM_2.5 before the survey date at each participant's address, using a validated, satellite-based, spatiotemporal model with a 10 km×10 km resolution. Participants with eGFR <60 ml/min per 1.73 m² or albuminuria were defined as having CKD. We used a logistic regression model to estimate the association and analyzed the influence of potential modifiers.

RESULTS

The 2-year mean PM_2.5 concentration was 57.4 μg/m³, with a range from 31.3 to 87.5 μg/m³. An increase of 10 μg/m³ in PM_2.5 was positively associated with CKD prevalence (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.22 to 1.35) and albuminuria (OR, 1.39; 95% CI, 1.32 to 1.47). Effect modification indicated these associations were significantly stronger in urban areas compared with rural areas, in males compared with females, in participants aged <65 years compared with participants aged ≥65 years, and in participants without comorbid diseases compared with those with comorbidities.

CONCLUSIONS

These findings regarding the relationship between long-term exposure to high ambient PM_2.5 levels and CKD in the general Chinese population provide important evidence for policy makers and public health practices to reduce the CKD risk posed by this pollutant.