Long-term air pollution exposure and decreased kidney function: A longitudinal cohort study in Bangkok Metropolitan Region, Thailand from 2002 to 2012

PM2.5 Exposure Induces Glomerular Hyperfiltration in Mice in a Gender-Dependent Manner

As one of the most common air pollutants, fine particulate matter (PM2.5) increases the risk of diseases in various systems, including the urinary system. In the present study, we exposed male and female C57BL/6J mice to PM2.5 for 8 weeks. Examination of renal function indices, including creatinine (CRE), blood urea nitrogen (BUN), uric acid (UA), and urinary microalbumin, indicated that the kidneys of female mice, not male mice, underwent early renal injury, exhibiting glomerular hyperfiltration. Meanwhile, pathological staining showed that the kidneys of female mice exhibited enlarged glomerulus that filled the entire Bowman's capsule in the female mice. Afterward, we explored the potential causes and mechanisms of glomerular hyperfiltration. Variations in mRNA levels of key genes involved in the renin-angiotensin system (RAS) and kallikrein-kinin system (KKS) demonstrated that PM2.5 led to elevated glomerular capillary hydrostatic pressure in female mice by disturbing the balance between the RAS and KKS, which in turn increased the glomerular filtration rate (GFR). In addition, we found that PM2.5 increased blood glucose levels in the females, which enhanced tubular reabsorption of glucose, attenuated macular dense sensory signaling, induced renal hypoxia, and affected adenosine triphosphate (ATP) synthesis, thus attenuating tubuloglomerular feedback (TGF)-induced afferent arteriolar constriction and leading to glomerular hyperfiltration. In conclusion, this study indicated that PM2.5 induced glomerular hyperfiltration in female mice by affecting RAS/KKS imbalances, as well as the regulation of TGF; innovatively unveiled the association between PM2.5 subchronic exposure and early kidney injury and its gender dependence; enriched the toxicological evidence of PM2.5 and confirmed the importance of reducing ambient PM2.5 concentrations.

Air quality and kidney health: Assessing the effects of PM10, PM2.5, CO, and NO2 on renal function in primary glomerulonephritis

BACKGROUND

While extensive studies have elucidated the relationships between exposure to air pollution and chronic diseases, such as cardiovascular disorders and diabetes, the intricate effects on specific kidney diseases, notably primary glomerulonephritis (GN)-an immune-mediated kidney ailment-are less well understood. Considering the escalating incidence of GN and conspicuous lack of investigative focus on its association with air quality, investigation is dedicated to examining the long-term effects of air pollutants on renal function in individuals diagnosed with primary GN.

METHODS

This retrospective cohort analysis was conducted on 1394 primary GN patients who were diagnosed at Seoul National University Bundang Hospital and Seoul National University Hospital. Utilizing time-varying Cox regression and linear mixed models (LMM), we examined the effect of yearly average air pollution levels on renal function deterioration (RFD) and change in estimated glomerular filtration rate (eGFR). In this context, RFD is defined as sustained eGFR of less than 60 mL/min per 1.73 m2.

RESULTS

During a mean observation period of 5.1 years, 350 participants developed RFD. Significantly, elevated interquartile range (IQR) levels of air pollutants-including PM10 (particles ≤10 micrometers, HR 1.389, 95 % CI 1.2-1.606), PM2.5 (particles ≤2.5 micrometers, HR 1.353, 95 % CI 1.162-1.575), CO (carbon monoxide, HR 1.264, 95 % CI 1.102-1.451), and NO2 (nitrogen dioxide, HR 1.179, 95 % CI 1.021-1.361)-were significantly associated with an increased risk of RFD, after factoring in demographic and health variables. Moreover, exposure to PM10 and PM2.5 was associated with decreased eGFR.

CONCLUSIONS

This study demonstrates a substantial link between air pollution exposure and renal function impairment in primary GN, accentuating the significance of environmental determinants in the pathology of immune-mediated kidney diseases.

Ambient ozone pollution impairs glucose homeostasis and contributes to renal function decline: Population-based evidence

Particulate matter pollution could increase the risk of kidney disease, while evidence for ozone exposure is less well-established. Here, we aimed to evaluate the effect of ozone pollution on renal function and explore mechanisms. We first conducted a cross-sectional study based on Wuhan Chronic Disease Cohort Study baseline information. We recruited 2699 eligible participants, estimated their residential ozone concentrations, collected fasting peripheral blood samples for biochemical analysis and calculated the estimated glomerular filtration rate (eGFR). The linear regression model was applied to evaluate the long-term association between ozone pollution and eGFR. Then, we recruited another 70 volunteers as a panel with 8 rounds follow-up visits. We calculated the eGFR and measured fasting blood glucose and lipid levels. The linear mixed-effect model along with mediation analysis were performed to confirm the short-term association and explore potential mechanisms, respectively. For the long-term association, a 10.95 μg/m3 increment of 3-year ozone exposure was associated with 2.96 mL/min/1.73 m2 decrease in eGFR (95%CI: -4.85, -1.06). Furthermore, the drinkers exhibited a pronounced declination of eGFR (-7.46 mL/min/1.73 m2, 95%CI: -11.84, -3.08) compared to non-drinkers in relation to ozone exposure. Additionally, a 19.02 μg/m3 increase in 3-day ozone concentrations was related to 2.51 mL/min/1.73 m2 decrease in eGFR (95%CI: -3.78, -1.26). Hyperglycemia and insulin resistance mediated 12.2% and 16.5% of the aforementioned association, respectively. Our findings indicated that higher ozone pollution could affect renal function, and the hyperglycemia and insulin resistance linked to ozone might be the underlying mechanisms.

Association between ambient air pollutant interaction with kidney function in a large Taiwanese population study

The associations and interactions between kidney function and other air pollutants remain poorly defined. Therefore, the aim of this study was to evaluate associations among air pollutants, including particulate matter (PM) with a diameter ≤ 2.5 μm (PM2.5), PM10 (PM with a diameter ≤ 10 μm), carbon monoxide (CO), nitrogen oxide (NO), nitrogen oxides (NOx), sulfur dioxide (SO2), and ozone (O3) with kidney function, and explore interactions among these air pollutants on kidney function. We used the Taiwan Air Quality Monitoring and Taiwan Biobank databases to derive data on community-dwelling individuals in Taiwan and daily air pollution levels, respectively. We enrolled 26,032 participants. Multivariable analysis showed that high levels of PM2.5, PM10, O3 (all p < 0.001), and SO2 (p = 0.001) and low levels of CO, NO (both p < 0.001), and NOx (p = 0.047) were significantly correlated with low estimated glomerular filtration rate (eGFR). With regard to negative effects, the interactions between PM2.5 and PM10 (p < 0.001), PM2.5 and PM10 (p < 0.001), PM2.5 and SO2, PM10 and O3 (both p = 0.025), PM10 and SO2 (p = 0.001), and O3 and SO2 (p < 0.001) on eGFR were significantly negatively. High PM10, PM2.5, O3, and SO2 were associated with a low eGFR, whereas high CO, NO, and NOx were associated with a high eGFR. Furthermore, negative interactions between PM2.5 and PM10, O3 and SO2, PM10 and O3, PM2.5 and SO2, and PM10 and SO2 on eGFR were observed. The findings of this study have important implications for public health and environmental policy. Specifically, the results of this study may be useful in individuals and organizations to take action to reduce air pollution and promote public health.

A FRET-based ratiometric fluorescent probe for SO32- detection in Chinese medicine and living cells

Chinese herbal medicine is receiving more and more attention at home and abroad as a traditional Chinese clinical medicine. To make herbal medicines can be preserved for a long time, they are usually fumigated with sulfur. However, after the medicinal materials have been fumigated with sulfur, SO₂ residues will remain, which, when exposed to water, will create sulfites and bisulfites. Excessive sulfites can cause a variety of severe ailments and diminish the quality and effectiveness of therapeutic plants. Therefore, developing an effective SO₃^2-/HSO₃^- detection method is important. This study chose coumarin derivatives as fluorescent acceptors and pyridinium acrylonitrile structures as fluorescent donors to create a ratiometric fluorescent probe CPA using the fluorescence resonance energy transfer (FRET) effect. The probe CPA exhibited a fluorescence transition from red to green under excitation at 405 nm with an interval of 149 nm, a reaction time of less than 1 min, a low detection limit of 86 nM, and the probe CPA has good specific recognition of SO₃^2- and is resistant to interference. In addition, CPA has low in vitro cytotoxicity and can successfully detect endogenous sulfites in living cells.

Combined effects of ambient air pollution and PM2.5 components on renal function and the potential mediation effects of metabolic risk factors in China

Growing evidence links long-term air pollution exposure with renal function. However, little research has been conducted on the combined effects of air pollutant mixture on renal function and multiple mediation effects of metabolic risk factors. This study enrolled 8996 adults without chronic kidney disease (CKD) at baseline from the CHCN-BTH cohort study. Three-year exposure to air pollutants [particulate matter ≤ 2.5 µm (PM_2.5), PM₁₀, PM₁, ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and carbon monoxide (CO)] and PM_2.5 components [black carbon (BC), ammonium (NH₄⁺), nitrate (NO₃^-), sulfate (SO₄^2-) and organic matter (OM)] were assessed using well-validated machine learning methods. Linear mixed models were applied to investigate the associations between air pollutants and estimated glomerular filtration rate (eGFR). Quantile G-computation was used to assess the combined effects of pollutant mixtures. Causal mediation analysis and Bayesian mediation analysis were employed to estimate the mediation effects of metabolic risk factors. An interquartile range increases in BC (-0.256, 95 %CI: -0.331, -0.180) and OM (-0.603, 95 %CI: -0.810, -0.397) were significantly associated with eGFR decline; while O₃ (1.151, 95 %CI: 0.813, 1.489), PM₁₀ (0.721, 95 %CI: 0.309, 1.133), NH₄⁺ (0.990, 95 %CI: 0.638, 1.342), and NO₃^- (0.610, 95 %CI: 0.405, 0.815) were associated with higher eGFR. The combined effect of the PM_2.5 component mixture was found to be associated with lower eGFR (-1.147, 95 % CI: -1.456, -0.839), with OM contributing 72.4 % of the negative effect. Univariate mediation analyses showed that high-density lipoprotein (HDL) mediated 7.1 %, 6.9 %, and 6.1 % effects of O₃, BC, and OM, respectively. However, these mediation effects were not significant in Bayesian mediation analysis. These findings suggest the effect of the PM_2.5 component mixture on eGFR decline and the strong contribution of OM. Metabolic risk factors may not mediate the effects of air pollutants. Further study is warranted to clarify the potential mechanisms involved.

Residential greenness and kidney function: A cohort study of Thai employees

Higher residential greenness is associated with a lower risk of chronic kidney disease, but evidence on the association between greenness exposure and kidney function has not been conducted. Using cohort data from Electricity Generating Authority of Thailand (EGAT) employees, we investigated the association between long-term exposure to greenness and kidney function using estimated glomerular filtration rate (eGFR) in Bangkok Metropolitan Region (BMR), Thailand. We analyzed data from 2022 EGAT workers (aged 25-55 years at baseline) from 2009 to 2019. The level of greenness was calculated using the satellite-derived Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI). From 2008 to 2019, the average concentration of each air pollutant (PM₁₀, O₃, NO₂, SO₂, and CO) at the sub-district level in BMR was generated using the Kriging method. Long-term exposure for each participant was defined as the 1-year average concentrations before the date of the physical examination in 2009, 2014, and 2019. We employed linear mixed effects models to evaluate associations of NDVI and EVI with eGFR. The robustness of the results was also tested by including air pollutants in the models. After relevant confounders were controlled, the interquartile range increase in NDVI was associated with higher eGFR [1.03% (95%CI: 0.33, 1.74)]. After PM₁₀ and SO₂ were included in the models, the associations between NDVI and eGFR became weaker. The additions of O₃, NO₂, and CO strengthened the associations between them. In contrast, we did not find any association between EVI and eGFR. In conclusion, there was a positive association between NDVI and eGFR, but not for EVI. Air pollutants had a significant impact on the relationship between NDVI and eGFR. Additional research is needed to duplicate this result in various settings and populations to confirm our findings.

Fine and ultrafine particle- and gas-polycyclic aromatic hydrocarbons affecting southern Thailand air quality during transboundary haze and potential health effects

Distribution of PM_0.1, PM₁ and PM_2.5 particle- and gas-polycyclic aromatic hydrocarbons (PAHs) during the 2019 normal, partial and strong haze periods at a background location in southern Thailand were investigated to understand the behaviors and carcinogenic risks. PM₁ was the predominant component, during partial and strong haze periods, accounting for 45.1% and 52.9% of total suspended particulate matter, respectively, while during normal period the contribution was only 34.0%. PM_0.1 concentrations, during the strong haze period, were approximately 2 times higher than those during the normal period. Substantially increased levels of particle-PAHs for PM_0.1, PM₁ and PM_2.5 were observed during strong haze period, about 3, 5 and 6 times higher than those during normal period. Gas-PAH concentrations were 10 to 36 times higher than those of particle-PAHs for PM_2.5. Average total Benzo[a]Pyrene Toxic Equivalency Quotients (BaP-TEQ) in PM_0.1, PM₁ and PM_2.5 during haze periods were about 2-6 times higher than in the normal period. The total accumulated Incremental Lifetime Cancer Risks (ILCRs) in PM_0.1, PM₁ and PM_2.5 for all the age-specific groups during the haze effected scenario were approximately 1.5 times higher than those in non-haze scenario, indicating a higher potential carcinogenic risk. These observations suggest PM_0.1, PM₁ and PM_2.5 were the significant sources of carcinogenic aerosols and were significantly affected by transboundary haze from peatland fires. This leads to an increase in the volume of smoke aerosol, exerting a significant impact on air quality in southern Thailand, as well as many other countries in lower southeast Asia.

Ambient ozone pollution and prevalence of chronic kidney disease: A nationwide study based on the China National survey of chronic kidney disease

The health hazards of ambient ozone (O₃) pollution are receiving increasing attention worldwide. However, the evidence on the association between O₃ and risks of chronic kidney disease (CKD) remains insufficient and inconsistent, particularly in developing countries where there is an absence of macroscopic investigations at a large population scale. Based on data from a representative nationwide cross-sectional CKD survey in 13 Chinese provinces and a high resolution O₃ air pollution inversion dataset, generalized linear models were used to evaluate the associations of O₃ concentration with prevalence of CKD. The results of this study suggested that long-term O₃ exposure was positively associated with the risk of CKD. A 10 μg/m³ increment in O₃ concentration was associated with an increased odds of CKD prevalence [OR = 1.11 (95% CI: 1.03, 1.21)] among all the 47,086 participants. Stronger associations were found in urban regions, younger adults <65 years, and people with higher socio-economic status (income and education level). A 10 μg/m³ increment in O₃ concentration was associated with a higher increased odds of CKD prevalence in urban regions [OR = 1.31 (95% CI: 1.16, 1.47)] compared to rural regions [OR = 0.95 (95% CI: 0.84, 1.08), P for subgroup difference<0.001]. A stronger association of O₃ concentration with CKD prevalence was found among younger people aged <65 years [OR = 1.21 (95% CI: 1.10, 1.33)] compared to those aged ≥65 years [OR = 0.92 (95% CI: 0.79, 1.07), P for subgroup difference = 0.003]. Our study demonstrated that long-term O₃ exposure may increase risk of CKD in the general Chinese population, and the findings stressed the importance of persistent efforts in air pollution prevention and control.

PM2.5 Induces Early Epithelial Mesenchymal Transition in Human Proximal Tubular Epithelial Cells through Activation of IL-6/STAT3 Pathway

Particulate matter exposure has been known as a potential risk for the global burden of disease, such as respiratory and cardiovascular diseases. Accumulating evidence suggests that PM2.5 (particulate matter with a diameter less than 2.5 μm) is associated with increased risk of kidney disease, but the mechanisms underlying the renal injury caused by PM2.5 remain to be elucidated. This study investigated the effects of PM2.5 on human proximal tubular epithelial (HK-2) cells by monolayer and 3D spheroid cultures and explored the potential mechanisms. The typical morphology of HK-2 cells showed epithelial–mesenchymal transition (EMT), resulting in reduced adhesion and enhanced migration after PM2.5 exposure, and was accompanied by decreased E-cadherin expression and increased vimentin and α-SMA expressions. Exposure to PM2.5 in the HK-2 cells could lead to an increase in interleukin-6 (IL-6) levels and cause the activation of signal transducer and activator of transcription 3 (STAT3), which is involved in EMT features of HK-2 cells. Furthermore, blocking IL-6/STAT3 signaling by an IL-6 neutralizing antibody or STAT3 inhibitor was sufficient to reverse PM2.5-induced EMT characteristics of the HK-2 cells. Our study suggests that PM2.5 could induce early renal tubule cell injury, contributing to EMT change, and the induction of IL-6/STAT3 pathway may play an important role in this process.