The Kidney Injury Induced by Short-Term PM2.5 Exposure and the Prophylactic Treatment of Essential Oils in BALB/c Mice

Particulate Matter-Induced Neurotoxicity: Unveiling the Role of NOX4-Mediated ROS Production and Mitochondrial Dysfunction in Neuronal Apoptosis

Urban air pollution, a significant environmental hazard, is linked to adverse health outcomes and increased mortality across various diseases. This study investigates the neurotoxic effects of particulate matter (PM), specifically PM2.5 and PM10, by examining their role in inducing oxidative stress and subsequent neuronal cell death. We highlight the novel finding that PM increases mitochondrial ROS production via stimulating NOX4 activity, not through its expression level in Neuro-2A cells. Additionally, PMs provoke ROS production via increasing the expression and activity of NOX2 in SH-SY5Y human neuroblastoma cells, implying differential regulation of NOX proteins. This increase in mitochondrial ROS triggers the opening of the mitochondrial permeability transition pore (mPTP), leading to apoptosis through key mediators, including caspase3, BAX, and Bcl2. Notably, the voltage-dependent anion-selective channel 1 (VDAC1) increases at 1 µg/mL of PM2.5, while PM10 triggers an increase from 10 µg/mL. At the same concentration (100 µg/mL), PM2.5 causes 1.4 times higher ROS production and 2.4 times higher NOX4 activity than PM10. The cytotoxic effects induced by PMs were alleviated by NOX inhibitors GKT137831 and Apocynin. In SH-SY5Y cells, both PM types increase ROS and NOX2 levels, leading to cell death, which Apocynin rescues. Variability in NADPH oxidase sources underscores the complexity of PM-induced neurotoxicity. Our findings highlight NOX4-driven ROS and mitochondrial dysfunction, suggesting a potential therapeutic approach for mitigating PM-induced neurotoxicity.

Early-life exposure to ambient air pollutants and kidney function in adolescents: a cohort study based on the 'Children of 1997' Hong Kong birth cohort

OBJECTIVES

Air pollution is increasingly linked to impaired kidney function in adults. However, little is known about how early-life exposure to air pollutants affects kidney function in adolescents.

STUDY DESIGN

Cohort study.

METHODS

We leveraged data from the 'Children of 1997' Hong Kong population-representative birth cohort (N = 8327). Residential exposure to average ambient levels of four air pollutants, including inhalable particle (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), and nitrogen monoxide (NO), during in utero, infancy, and childhood periods was estimated using the inverse distance weighting. Kidney function was assessed using estimated glomerular filtration rate (eGFR) calculated from age-adjusted equations for adolescents. Generalized linear regression was used to examine the association of air pollutant exposure in each period with kidney function at 17.6 years. Two-pollutant models tested the robustness of the association.

RESULTS

Of the 3350 participants included, 51.4% were boys. Exposure to PM10 was associated with poorer kidney function. Each interquartile range increment in PM10 was inversely associated with eGFR (β: -2.933, 95% confidence interval -4.677 to -1.189) in utero, -2.362 (-3.992 to -0.732) infancy, -2.708 (-4.370 to -1.047) childhood, and -2.828 (-4.409 to -1.247) overall. Exposure to PM10 and SO2in utero had a stronger inverse association with kidney function in males. The associations were robust to PM10 exposure in two-pollutant models.

CONCLUSIONS

Our findings suggest that early-life exposure to ambient PM10 and SO2 is associated with reduced kidney function in adolescents, especially exposure in utero.

PM2.5 induces renal tubular injury by activating NLRP3-mediated pyroptosis

Fine particulate matter (PM2.5)-related health issues have received increasing attention as a worldwide public health problem, and PM2.5-related chronic kidney disease (CKD) has been emerging over the years. Limited research has focused on the mechanism of PM2.5-induced kidney disease. To investigate the impact of PM2.5 on the kidney and its potential mechanism, we generated a PM2.5-exposed C57BL/6 mouse model by using Shanghai Meteorological and Environment Animal Exposure System (Shanghai-METAS) for 12 weeks, urine, blood and kidney tissues were collected. The pathological changes and the function of the kidney were measured after PM2.5 exposure for 12 weeks. Along with glomerular damage, tubular damage was also severe in PM2.5-induced mice. The results of mRNA-seq indicate that pyroptosis is involved. Pyroptosis is defined as caspase-1-dependent programmed cell death in response to insults. The expression of the nucleotide-binding and oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3), Caspase-1, gasdermin D (GSDMD) and IL-1β was detected. NLRP3 inflammasome activation and subsequent pyroptosis were observed in PM2.5-exposed kidney tissues and PM2.5-exposed Bumpt cells too. At the meantime, the inhibitors of NLRP3 and caspase-1 were applied to the PM2.5 exposed Bumpt cells. It turned out to have a significant rescue effect of the inhibitors. This study revealed new insights into PM2.5-induced kidney injury and specific kidney pathological damage, as well as morphological changes, and defined the important role of pyroptosis in PM2.5-induced kidney dysfunction.

Associations between short-term exposure to PM2.5, NO2 and O3 pollution and kidney-related conditions and the role of temperature-adjustment specification: A case-crossover study in New York state

Epidemiologic evidence on the relationship between air pollution and kidney disease remains inconclusive. We evaluated associations between short-term exposure to PM_2.5, NO₂ and O₃ and unplanned hospital visits for seven kidney-related conditions (acute kidney failure [AKF], urolithiasis, glomerular diseases [GD], renal tubulo-interstitial diseases, chronic kidney disease, dysnatremia, and volume depletion; n = 1,209,934) in New York State (2007-2016). We applied a case-crossover design with conditional logistic regression, controlling for temperature, dew point temperature, wind speed, and solar radiation. We used a three-pollutant model at lag 0-5 days of exposure as our main model. We also assessed the influence of model adjustment using different specifications of temperature by comparing seven temperature metrics (e.g., dry-bulb temperature, heat index) and five intraday temperature measures (e.g., daily mean, daily minimum, nighttime mean), according to model performance and association magnitudes between air pollutants and kidney-related conditions. In our main models, we adjusted for daytime mean outdoor wet-bulb globe temperature, which showed good model performance across all kidney-related conditions. We observed the odds ratios (ORs) for 5 μg/m³ increase in daily mean PM_2.5 to be 1.013 (95% confidence interval [CI]: 1.001, 1.025) for AKF, 1.107 (95% CI: 1.018, 1.203) for GD, and 1.027 (95% CI: 1.015, 1.038) for volume depletion; and the OR for 5 ppb increase in daily 1-hour maximum NO₂ to be 1.014 (95% CI; 1.008, 1.021) for AKF. We observed no associations with daily 8-hour maximum O₃ exposure. Association estimates varied by adjustment for different intraday temperature measures: estimates adjusted for measures with poorer model performance resulted in the greatest deviation from estimates adjusted for daytime mean, especially for AKF and volume depletion. Our findings indicate that short-term exposure to PM_2.5 and NO₂ is a risk factor for specific kidney-related conditions and underscore the need for careful adjustment of temperature in air pollution epidemiologic studies.

Sipeimine attenuates PM2.5-induced lung toxicity via suppression of NLRP3 inflammasome-mediated pyroptosis through activation of the PI3K/AKT pathway

Exposure to fine particulate matter (PM2.5), an environmental pollutant, significantly contributes to the incidence of and risk of mortality associated with respiratory diseases. Sipeimine (Sip) is a steroidal alkaloid in fritillaries that exerts antioxidative and anti-inflammatory effects. However, protective effect of Sip for lung toxicity and its mechanism to date remains poorly understood. In the present study, we investigated the lung-protective effect of Sip via establishing the lung toxicity model of rats with orotracheal instillation of PM2.5 (7.5 mg/kg) suspension. Sprague-Dawley rats were intraperitoneally administered with Sip (15 mg/kg or 30 mg/kg) or vehicle daily for 3 days before instillation of PM2.5 suspension to establish the model of lung toxicity. The results found that Sip significantly improved pathological damage of lung tissue, mitigated inflammatory response, and inhibited lung tissue pyroptosis. We also found that PM2.5 activated the NLRP3 inflammasome as evidenced by the upregulation levels of NLRP3, cleaved-caspase-1, and ASC proteins. Importantly, PM2.5 could trigger pyroptosis by increased levels of pyroptosis-related proteins, including IL-1β, cleaved IL-1β, and GSDMD-N, membrane pore formation, and mitochondrial swelling. As expected, all these deleterious alterations were reversed by Sip pretreatment. These effects of Sip were blocked by the NLRP3 activator nigericin. Moreover, network pharmacology analysis showed that Sip may function via the PI3K/AKT signaling pathway and animal experiment validate the results, which revealed that Sip inhibited NLRP3 inflammasome-mediated pyroptosis by suppressing the phosphorylation of PI3K and AKT. Our findings demonstrated that Sip inhibited NLRP3-mediated cell pyroptosis through activation of the PI3K/AKT pathway in PM2.5-induced lung toxicity, which has a promising application value and development prospect against lung injury in the future.

Lactoferrin attenuated urban particulate matter-induced nephrotoxicity by regulating the CSF2/CENPE axis

Several epidemiological studies regarding the adverse effect of air pollution have notably accelerated in recent years. Urban particulate matter (PM) gains access to the respiratory system and translocates into the circulation to affect several tissues, such as the liver and kidneys. Lactoferrin is a substance belonging to the non-heme iron-binding glycoprotein which is present in breast milk and other exocrine fluids. Lactoferrin is protective against many pathophysiological conditions. In the present study, we explored the potential influence of lactoferrin on PM-induced nephrotoxicity. We found that lactoferrin rescued PM-induced cell death but did not affect apoptosis in human kidney cells. Lactoferrin decreased necroptosis and fibrosis but increased autophagy in human kidney cells. Furthermore, the gene expression profiles of PM and lactoferrin were analyzed by RNA sequencing. The transcriptional profiles were uploaded and analyzed by ingenuity pathway analysis software and gene set enrichment analysis. The results showed that the crucial role of the CSF2/CENPE pathway was involved in human kidney cells treated with PM and lactoferrin. In a mouse model, lactoferrin ameliorates PM-induced nephrotoxicity by regulating necroptosis, fibrosis, autophagy and the CSF2/CENPE axis. In summary, these findings showed that lactoferrin could be a novel therapeutic or preventive agent for renal disorders caused by airborne PM pollution.

Exposure to airborne particulate matter induces renal tubular cell injury in vitro: the role of vitamin D signaling and renin-angiotensin system

Background

Exposure to air pollution can interfere with the vitamin D endocrine system. This study investigated the effects of airborne particulate matter (PM) on renal tubular cell injury in vitro and explored the underlying mechanisms.

Methods

HK-2 human renal proximal tubule cells were treated with PM with or without 1,25(OH)₂D₃ analog, 19-Nor-1,25(OH)₂D₂ (paricalcitol, 10 nM) for 48 h. The dose- and time-dependent cytotoxicity of PM with or without paricalcitol was determined via cell counting kit-8 assay. Cellular oxidative stress was assessed using commercially available enzyme-linked immunosorbent assay kits. The protein expression of vitamin D receptor (VDR), cytochrome P450(CYP)27B1, CYP24A1, renin, angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1), nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-kB (NF-kB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 was determined.

Results

PM exposure decreased HK-2 cell viability in a dose- and time-dependent manner. The activities of superoxide dismutase and malondialdehyde in HK-2 cells increased significantly in the group exposed to PM. PM exposure decreased VDR and Nrf2, while increasing CYP27B1, renin, ACE, AT1, NF-kB, TNF-α, and IL-6. The expression of VDR, CYP27B1, renin, ACE, AT1, and TNF-α was reversed by paricalcitol treatment. Paricalcitol also restored the cell viability of PM-exposed HK-2 cells.

Conclusion

Our findings indicate that exposure to PM induces renal proximal tubular cell injury, concomitant with alteration of vitamin D endocrine system and renin angiotensin system. Vitamin D could attenuate renal tubular cell damage following PM exposure by suppressing the renin-angiotensin system and by partially inhibiting the inflammatory response.

The Physiological Effects of Air Pollution: Particulate Matter, Physiology and Disease

Nine out of 10 people breathe air that does not meet World Health Organization pollution limits. Air pollutants include gasses and particulate matter and collectively are responsible for ~8 million annual deaths. Particulate matter is the most dangerous form of air pollution, causing inflammatory and oxidative tissue damage. A deeper understanding of the physiological effects of particulate matter is needed for effective disease prevention and treatment. This review will summarize the impact of particulate matter on physiological systems, and where possible will refer to apposite epidemiological and toxicological studies. By discussing a broad cross-section of available data, we hope this review appeals to a wide readership and provides some insight on the impacts of particulate matter on human health.

Association between gaseous air pollutants and idiopathic nephrotic syndrome in children: a 12-year population-based cohort study

Background

To date, there is insufficient knowledge about the association of air pollution and childhood nephrotic syndrome in the real world. This study aimed to evaluate the effects of the three common gaseous air pollutants, including sulfur dioxide, total hydrocarbon, and methane, on the risk of idiopathic nephrotic syndrome (INS) in children.

Methods

We collected data from the Taiwan National Health Insurance Research Database and Taiwan Air Quality-Monitoring Database. Children younger than 18 years old, identified from January 1, 2000, were followed up until the first diagnosis of INS was established or until December 31, 2012. We measured the incidence rates and hazard ratios for INS stratified based on the quartiles (Q1–Q4) of air pollutant concentration. Multivariate Cox proportional hazards models were also applied by adjusting age, sex, monthly income, and urbanization.

Results

Compared with participants exposed to Q1 concentrations, the adjusted hazard ratios (aHRs) for INS increased progressively along the four quartiles of sulfur dioxide, total hydrocarbon, and methane, from 1 (Q1) to 1.78 (Q4), 1 (Q1) to 3.49 (Q4), 1 (Q1) to 7.83 (Q4), respectively.

Conclusions

Our study revealed that children with exposure to higher concentrations of sulfur dioxide, total hydrocarbon, and methane was associated with an increased risk of INS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13052-022-01269-8.

Adverse effects of PM2.5 on cardiovascular diseases

As an air pollutant, fine particulate matter with a diameter  ≤ 2.5 μm (PM_2.5) can enter the body through the respiratory tract and cause adverse cardiovascular effects. Here, the effects of PM_2.5 on atherosclerosis, hypertension, arrhythmia, myocardial infarction are summarized from the perspective researches of human epidemiology, animal, cell and molecule. The results of this review should be proved useful as a scientific basis for the prevention and treatment of cardiovascular disease caused by PM_2.5.

Critical windows of perinatal particulate matter (PM2.5) exposure and preadolescent kidney function

Air pollution exposure, especially particulate matter ≤2.5 μm in diameter (PM2.5), is associated with poorer kidney function in adults and children. Perinatal exposure may occur during susceptible periods of nephron development. We used distributed lag nonlinear models (DLNMs) to examine time-varying associations between early life daily PM2.5 exposure (periconceptional through age 8 years) and kidney parameters in preadolescent children aged 8-10 years. Participants included 427 mother-child dyads enrolled in the PROGRESS birth cohort study based in Mexico City. Daily PM2.5 exposure was estimated at each participant's residence using a validated satellite-based spatio-temporal model. Kidney function parameters included estimated glomerular filtration rate (eGFR), serum cystatin C, and blood urea nitrogen (BUN). Models were adjusted for child's age, sex and body mass index (BMI) z-score, as well as maternal education, indoor smoking report and seasonality (prenatal models were additionally adjusted for average first year of life PM2.5 exposure). We also tested for sex-specific effects. Average perinatal PM2.5 was 22.7 μg/m3 and ranged 16.4-29.3 μg/m3. Early pregnancy PM2.5 exposures were associated with higher eGFR in preadolescence. Specifically, we found that PM2.5 exposure between weeks 1-18 of gestation was associated with increased preadolescent eGFR, whereas exposure in the first 14 months of life after birth were associated with decreased eGFR. Specifically, a 5 μg/m3 increase in PM2.5 during the detected prenatal window was associated with a cumulative increase in eGFR of 4.44 mL/min/1.732 (95%CI: 1.37, 7.52), and during the postnatal window we report a cumulative eGFR decrease of -10.36 mL/min/1.732 (95%CI: -17.68, -3.04). We identified perinatal windows of susceptibility to PM2.5 exposure with preadolescent kidney function parameters. Follow-up investigating PM2.5 exposure with peripubertal kidney function trajectories and risk of kidney disease in adulthood will be critical.

The influence of PM2.5 exposure on kidney diseases

The harm of air pollution to public health has become a research hotspot, especially atmospheric fine-particulate matter (PM_2.5). In recent years, epidemiological investigations have confirmed that PM_2.5 is closely related to chronic kidney disease and membranous nephropathy Basic research has demonstrated that PM_2.5 has an impact on the normal function of the kidneys through accumulation in the kidney, endothelial dysfunction, abnormal renin-angiotensin system, and immune complex deposition. Moreover, the mechanism of PM_2.5 damage to the kidney involves inflammation, oxidative stress, apoptosis, DNA damage, and autophagy. In this review, we summarized the latest developments in the effects of PM_2.5 on kidney disease in human and animal studies, so as to provide new ideas for the prevention and treatment of kidney disease.

Associations of Carbonaceous Compounds and Water-Soluble Inorganic Ions in Ambient PM2.5 with Renal Function in Older Individuals: The China BAPE Study

Exposure to fine particulate matter (PM_2.5) is proven to be associated with a decline in renal function. However, few studies have explored the acute renal damage from carbonaceous compounds and water-soluble inorganic ions (WSIIs), which constitute the bulk of total PM_2.5 mass. We examined the acute effect of these constituents of ambient PM_2.5 on renal function in older Chinese individuals. Seventy-one healthy people aged 60-69 years from Jinan, China, were enrolled and visited monthly and asked to complete survey questionnaires, undergo physical exams, and provide blood samples. The hourly concentrations of organic carbon, elemental carbon (EC), and WSIIs in ambient PM_2.5 were collected from a fixed-site monitoring station. The association between PM_2.5 constituents and estimated glomerular filtration rate (eGFR) was evaluated using linear mixed-effects models after controlling for a series of covariates. We observed that ambient carbonaceous compounds and WSIIs were associated with a significant decline in renal function. The interquartile range increased in the 24 h moving average of carbonaceous compounds, and WSIIs in ambient PM_2.5 were associated with -13.11% [95% confidence interval (95% CI): -19.49, -6.21%] to -0.81% (95% CI: -4.17, 2.67%) changes in eGFR. We found significant associations between EC, chlorine (Cl^-), sodium (Na⁺), and magnesium (Mg²⁺) and eGFR in single-pollutant, constituent-PM_2.5, and residual-constituent models with a lag period of 0-24 h. This study demonstrated that carbonaceous compounds and WSIIs in PM_2.5 were inversely associated with renal function.

Short-term associations between particulate matter air pollution and hospital admissions through the emergency room for urinary system disease in Beijing, China: A time-series study

Evidence on the relationship between particulate matter air pollution and urinary system disease (UD) is scarce. This study aims to evaluate the associations between short-term exposures to PM_2.5 and PM₁₀ and risk of daily UD inpatient hospital admissions through the emergency room (ER-admissions) in Beijing. We obtained 41,203 weekday UD ER-admissions for secondary and tertiary hospitals in all 16 districts in Beijing during 2013-2018 from the Beijing Municipal Health Commission Information Center and obtained district-level air pollution concentrations based on 35 fixed monitoring stations in Beijing. We conducted a two-stage time-series analysis, with district-specific generalized linear models for each of Beijing's 16 districts, followed by random effects meta-analysis to obtain pooled risk estimates. We evaluated lagged and cumulative associations up to 30 days. In single-pollutant models, for both PM_2.5 and PM₁₀, cumulative exposure averaged over the day of admission and the previous 10 days (lag 0-10 days) showed the strongest association, with per interquartile range increases of PM_2.5 or PM₁₀ concentrations associated with a 7.5 % (95 % confidence interval [CI]: 3.0 %-12.2 %) or 6.0 % (95 % CI: 1.1 %-11.2 %) increased risk of daily UD hospital admissions, respectively. The risk estimates were robust to adjustment for co-pollutants and to a variety of sensitivity analyses. However, due to the strong correlation between PM_2.5 and PM₁₀ concentrations, we were unable to disentangle the respective relationships between these two exposures and UD risk. In this study, we found that short-term exposures to PM_2.5 and PM₁₀ are risk factors for UD morbidity and that cumulative exposure to PM pollution over a period of one to two weeks (i.e., 11 days) could be more important for UD risk than transient exposure during each of the respective single days.

1,2,4-Trimethoxybenzene selectively inhibits NLRP3 inflammasome activation and attenuates experimental autoimmune encephalomyelitis

NOD-like receptor (NLR) family pyrin domain-containing-3 (NLRP3) inflammasome is implicated in inflammation-associated diseases such as multiple sclerosis, Parkinson's disease, and stroke. Targeting the NLRP3 inflammasome is beneficial to these diseases, but few NLRP3 inflammasome-selective inhibitors are identified to date. Essential oils (EOs) are liquid mixtures of volatile and low molecular-weight organic compounds extracted from aromatic plants, which show various pharmacological activities, including antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory properties. In this study we screened active ingredients from essential oils, and identified 1,2,4-trimethoxybenzene (1,2,4-TTB) as a selective NLRP3 inflammasome inhibitor. We showed that 1,2,4-TTB (1 mM) markedly suppressed nigericin- or ATP-induced NLRP3 inflammasome activation, thus decreased caspase-1 activation and IL-1β secretion in immortalized murine bone marrow-derived macrophages (iBMDMs) and in primary mouse microglia. Moreover, 1,2,4-TTB specifically inhibited the activation of NLRP3 inflammasome without affecting absent in melanoma 2 (AIM2) inflammasome activation. We further demonstrated that 1,2,4-TTB inhibited oligomerization of the apoptosis-associated speck-like protein containing a CARD (ASC) and protein-protein interaction between NLRP3 and ASC, thus blocking NLRP3 inflammasome assembly in iBMDMs and in primary mouse macrophages. In mice with experimental autoimmune encephalomyelitis (EAE), administration of 1,2,4-TTB (200 mg · kg^-1 · d^-1, i.g. for 17 days) significantly ameliorated EAE progression and demyelination. In conclusion, our results demonstrate that 1,2,4-TTB is an NLRP3 inflammasome inhibitor and attenuates the clinical symptom and inflammation of EAE, suggesting that 1,2,4-TTB is a potential candidate compound for treating NLRP3 inflammasome-driven diseases, such as multiple sclerosis.

Effect of miR-132-3p on sepsis-induced acute kidney injury in mice via regulating HAVCR1/KIM-1

OBJECTIVE

To investigate the effect of miR-132-3p and HAVCR1/kidney injury molecule (KIM)-1 on sepsis-induced acute kidney injury (AKI) in mice.

METHODS

One hundred C57BL/6 mice were divided into five groups with 20 mice in each group: the normal group (normal mice), the model group (mice with sepsis), the miR-132-3p mimic group (miR-132-3p overexpression), the oe-HAVCR1/KIM-1 group (HAVCR1/KIM-1 overexpression), and the miR-132-3p mimic + oe-HAVCR1/KIM-1 group. Dual-luciferase reporter assay was performed to verify the targeting relationship between miR-132-3p and HAVCR1/KIM-1. The expressions of miR-132-3p and HAVCR1/KIM-1 in mice' kidneys, the levels of renal function markers, the expressions of apoptosis-associated proteins, the renal cell apoptosis rate, and the inflammatory factors in serum were all examined.

RESULTS

We found that miR-132-3p can target HAVCR1/KIM-1 and regulate its expression. Compared with the normal mice, the septic mice exhibited lower miR-132-3p level and higher HAVCR1/KIM-1 level (both P<0.05). Moreover, the septic mice had higher levels of cleaved caspase-3, Bax, blood urea nitrogen, creatinine, tumor necrosis factor-α, interleukin-1β, and interleukin-6, higher renal cell apoptosis rate, and lower Bcl-2 level than the normal mice (all P<0.05). MiR-132-3p overexpression could improve the renal function of the mice with sepsis and inhibit renal cell apoptosis and inflammatory progression, whereas HAVCR1/KIM1 overexpression exhibited an opposite effect and could block the renal protective effects of miR-132-3p overexpression on the septic mice.

CONCLUSION

MiR-132-3p overexpression can inhibit renal cell apoptosis and inflammatory progression via suppressing HAVCR1/KIM-1 expression, thereby exert renal protective effects on mice with sepsis.

2-Undecanone Protects against Fine Particle-Induced Kidney Inflammation via Inducing Mitophagy

Exposure to particulate matter has been associated with diseases of the respiratory and cardiovascular systems. Owing to the dense vasculature of the kidney, it has also been identified as a PM_2.5 target organ. A potential contributor to PM_2.5-mediated damage may be the promotion of inflammation. The essential oil 2-undecanone (2-methyl nonyl ketone) is an H. cordata isolate, and it has been shown to possess diverse pharmacologic effects, including anti-inflammatory properties. In this study we explored the ability of 2-undecanone to protect against PM_2.5-induced kidney inflammation and the exact mechanisms in this process. We found that PM_2.5 elevated the levels of certain inflammatory cytokines in BALB/c mice and in HEK 293 cells. Supplementation with 2-undecanone attenuated this PM_2.5-induced inflammatory injury. Interestingly, in HEK 293 cells, the PM_2.5-associated inflammation was aggravated by the mitophagy inhibitor Medivi-1, while it was attenuated by rapamycin, indicating that the mechanism of 2-undecanone-mediated inhibition of inflammation may relate to mitophagy. Meanwhile, 2-undecanone induces mitophagy in HEK 293 cells by suppressing Akt1-mTOR signaling. These results indicate that PM_2.5 can induce kidney inflammation, and mitophagy induced by 2-undecanone may play a protective role against this renal inflammation.

lncRNA Gm16410 Mediates PM2.5-Induced Macrophage Activation via PI3K/AKT Pathway

PM₂.₅ refers to atmospheric particulate matters with a diameter of less than 2.5 μm. The deposit of PM₂.₅ in lung cells can cause oxidative stress, leading to changes in macrophage polarity, which can subsequently cause pulmonary inflammation. Long-chain non-coding RNA (lncRNA) is a class of transcripts that regulate biological processes through multiple mechanisms. However, the role of lncRNA in PM₂.₅-induced lung inflammation has not been established. In this study, the biological effects and associated mechanism of lncRNA in PM₂.₅-induced change in macrophage polarity were investigated. The lncRNA-mediated PM₂.₅-induced macrophage inflammation and lung inflammation-associated injury were also determined. Mice were exposed to chronic levels of PM₂.₅, and changes in the expression of lncRNA in the lung were measured by lncRNA microarray. lncRNAs that showed significant changes in expression in response to PM₂.₅ were identified. lncRNA showing the biggest change was subjected to further analysis to determine its functional roles and mechanisms with respect to macrophage activation. The result showed that a significant reduction in expression of one lncRNA, identified as lncGm16410, was observed in the lung of mice and RAW264.7 cells following exposure to PM₂.₅. lncGm16410 suppressed PM₂.₅-induced macrophage activation via the SRC protein-mediated PI3K/AKT signaling pathway. PM₂.₅ promoted lung inflammation by downregulating the expression of lncGm16410, enhancing the activation of macrophages. Thus, lncGm16410 might provide new insight into the prevention of PM₂.₅ injury.

Fine Particulate Matter (PM2.5) and Chronic Kidney Disease

The impact of ambient particulate matter (PM) on public health has become a great global concern, which is especially prominent in developing countries. For health purposes, PM is typically defined by size, with the smaller particles having more health impacts. Particles with a diameter <2.5 μm are called PM_2.5. Initial research studies have focused on the impact of PM_2.5 on respiratory and cardiovascular diseases; nevertheless, an increasing number of data suggested that PM_2.5 may affect every organ system in the human body, and the kidney is of no exception. The kidney is vulnerable to particulate matter because most environmental toxins are concentrated by the kidney during filtration. According to the high morbidity and mortality related to chronic kidney disease, it is necessary to determine the effect of PM_2.5 on kidney disease and its mechanism that needs to be identified. To understand the current status of PM_2.5 in the atmosphere and their potential harmful kidney effects in different regions of the world this review article was prepared based on peer-reviewed scientific papers, scientific reports, and database from government organizations published after the year 1998. In this review, we focus on the worldwide epidemiological evidence linking PM_2.5 with chronic kidney disease and the effect of PM_2.5 on the chronic kidney disease (CKD) progression. At the same time, we also discuss the possible mechanisms of PM_2.5 exposure leading to kidney damage, in order to emphasize the contribution of PM_2.5 to kidney damage. A global database on PM_2.5 and kidney disease should be developed to provide new ideas for the prevention and treatment of kidney disease.

Personal exposure to fine particulate matter and renal function in children: A panel study

There is a lack of evidence regarding the association of short-term exposure to fine particulate matter (PM_2.5) with renal function in children and its underlying mechanism. We included 105 children aged 4-13 years from a panel study conducted in Wuhan, China with up to 3 repeated visits across 3 seasons from October 9, 2017 to June 1, 2018. We measured personal real-time PM_2.5 exposure concentration continuously for 72 h preceding each round of health examinations that included serum creatinine and cytokines. Linear mixed-effects models were performed to estimate the effects of PM_2.5 on estimated glomerular filtration rate (eGFR) over various lag times, and a mediation analysis was applied for the role of cytokines in association between PM_2.5 and eGFR. Results showed that personal exposure to PM_2.5 was dose-responsive related to decreased eGFR within lag 2 days. The effect was the strongest at lag 0 day with estimation of -1.69% [95% confidence interval (CI): -2.27%, -1.10%] in eGFR by a 10-μg/m³ increase in PM_2.5, and reached peak at lag 3 h, then declined over time. Such inverse relationships were more evident among children aged 4-6 years, or boys or those who lived proximity to major roadways <300 m. Notably, eGFR still held on to decrease even when PM_2.5 was below Class II Chinese ambient air quality standard at lag 0 day. Moreover, the effect of PM_2.5 on eGFR was significantly reduced in children with high and medium levels of serum chemokine ligand 27 (CCL27), but not in those with low CCL27. Furthermore, CCL27 was positively relevant to PM_2.5, and mediated proportion of CCL27 ranged from 3.75% to 6.61% in relations between PM_2.5 and decreased eGFR over various lag times. In summary, short-term PM_2.5 exposure might be dose-responsive associated with reduced eGFR whereby a mechanism partly involving CCL27 among healthy children.

Associations between Personal PM2.5 Elemental Constituents and Decline of Kidney Function in Older Individuals: the China BAPE Study

Long-term exposure to fine particulate matter (PM_2.5) is associated with kidney dysfunction. However, few studies have investigated acute effects of PM_2.5 elemental constituents on renal function. We evaluated associations between personal PM_2.5 and its elemental constituents and kidney function, assessed by an estimated glomerular filtration rate (eGFR) in Biomarkers of Air Pollutants Exposure in the Chinese aged 60-69 study. Seventy one older individuals were visited monthly between September 2018 and January 2019. Each participant wore a PM_2.5 monitor for 72 h, responded to a questionnaire, and underwent a physical examination with blood sampling. Linear mixed-effect models were used to estimate associations between personal PM_2.5 elemental constituents and eGFR. We found that significant changes in eGFR from -1.69% [95% confidence interval (CI): -3.34%, -0.01%] to -3.27% (95% CI: -5.04%, -1.47%) were associated with interquartile range (IQR) increases in individual PM_2.5 exposures at various lag periods (7-12, 13-24, 0-24, 25-48, and 49-72 h). An IQR increase in 72 h moving averages of copper, manganese, and titanium in personal PM_2.5 corresponded to -2.34% (95% CI: -3.67%, -0.99%) to -4.56% (95% CI: -7.04%, -2.00%) changes in eGFR. Personal PM_2.5 and some of its elemental constituents are inversely associated with eGFR in older individuals.

Air pollutants and subsequent risk of chronic kidney disease and end-stage renal disease: A population-based cohort study

Air pollutants have been reported to be a possible risk factor of chronic kidney disease (CKD). However, epidemiologic results regarding acidic gases and CKD have yet to be elucidated. We linked the Taiwan Air Quality Monitoring Database (TAQMD) to the Longitudinal Health Insurance Database. An observational cohort of 161,970 Taiwan citizens who had not been diagnosed with CKD was formed. The concentrations of air pollutant were classified into four levels based on quartile. Multivariable and univariable Cox proportional hazard regression models were used to assess the risk of developing CKD and end-stage renal disease (ESRD). Compared with Q1-level SO2, exposure to the Q4 level was at a 1.46-fold risk of developing CKD (95% confidence interval [CI] = 1.28-1.65) and 1.32-fold risk of ESRD (95% CI = 1.03-1.70). Compared with Q1-level NOx, exposure to the Q4 level was at a 1.39-fold higher risk of developing CKD (95% CI = 1.22-1.58) and 1.70-fold risk of ESRD (95% CI = 1.33-2.18). Compared with Q1-level NO, exposure to the Q4 level was at a 1.48-fold risk of CKD (95% CI = 1.30-1.68) and 1.54-fold risk of ESRD (95% CI = 1.20-1.98). Compared with Q1-level particles <2.5 μm (PM2.5), exposure to the Q4 level were at a 1.74-fold risk of CKD (95% CI = 1.53-1.98) and 1.69-fold risk of ESRD (95% CI = 1.32-2.16). Exposure to particulate and acidic gas air pollution was observed to be associated with an increased risk of CKD and ESRD.

Particulate matter pollution and hospital outpatient visits for endocrine, digestive, urological, and dermatological diseases in Nanjing, China

Clinical or pathological evidence demonstrated that air pollution could undermine other organ systems of human body besides respiratory and circulation systems. Investigations that directly relate hospital outpatient visits for endocrine (ENDO), digestive (DIGE), urological (UROL), and dermatological (DERM) diseases categories with ambient particulate matter (PM) are still lacking, particularly in heavily polluted cities. Here, we conducted a time-series analysis using 812,624, 1,111,342, 539,803, and 741,662 hospital visits for ENDO, DIGE, UROL, and DERM, respectively, in Nanjing, China from 2013 to 2019. A generalized additive model was applied to estimate the exposure-response associations. Results showed that a 10 μg/m³ increase in PM_2.5 concentration on lag 0 day was significantly associated with 0.59% (95% CI: 0.30%, 0.88%), 0.43% (0.15%, 0.70%), 0.36% (0.06%, 0.66%), and 0.65% (0.42%, 0.87%) increase for ENDO, DIGE, UROL, and DERM hospital visits, respectively. The estimated effects of PM₁₀ were slightly smaller but still statistically significant. The magnitude and significance of the associations between PM and four health outcomes were sensitive to additional adjustment for co-pollutants. Exposure-response relationships were linear for PM concentrations lower than 100 μg/m³ but the curves became nonlinear across the full range of exposures due to a flatten slope at higher concentrations. We also explored the effect modifications by season (cold or warm), age (5-18, 18-64, 65-74, or 75+ years), and sex (male or female). Results showed that the DERM-related population aged 65 years or older was more vulnerable to PM exposure, compared with the 5 to 17-year age group; the DERM-related population aged 75 years or older and 65 years or older was more vulnerable to PM_2.5 and PM₁₀ exposure, respectively, compared with the 18 to 64-year age group. Our study provided suggestive evidence that ambient PM pollution was associated with ENDO, DIGE, UROL, and DERM outpatient hospital visits in Nanjing, China.

Mutagenicity and Cytotoxicity of Particulate Matter Emitted from Biodiesel-Fueled Engines

Biodiesel engines produce several intermediate species, which can potentially harm the human health. The concentration of these species and their health risk potential varies depending on engine technology, fuel, and engine operating condition. In this study, experiments were performed on a large number of engines having different configurations (emissions norms/fuel used), which were operated at part load/full load using B20 (20% v/v biodiesel blended with mineral diesel) and mineral diesel. Experiments included measurement of gaseous emissions, and physical, chemical, and biological characterization of exhaust particulate matter (PM). Chemical characterization of PM was carried out for detecting polycyclic aromatic hydrocarbons (PAH's) and PM bound trace metals. The biological toxicity associated with PM was assessed using human embryonic kidney 293T cells (HEK 293T). The mutagenic potential of the PM was tested at three different concentrations (500, 100, and 50 μg/mL) using two different  Salmonella strains, TA98 and TA100, with and without liver S9 metabolic enzyme fraction. PM samples exhibited cytotoxic effect on HEK 293T cells (IC₅₀ < 100 μg/mL) and there was significant potential for reactive oxygen species (ROS) generation. Comparison of different engines showed that modern engines (Euro-III and Euro-IV compliant) produced relatively cleaner exhaust compared to older engines (Euro-II compliant). Biodiesel-fueled engines emitted lower number of particles compared to diesel-fueled engines. However, chemical characterization revealed that biodiesel-fueled engines exhaust PM contained several harmful PAHs and trace metals, which affected the biological activity of these PM, as reflected in the biological investigations. Mutagenicity and cytotoxicity of PM from biodiesel-fueled engines were relatively higher compared to their diesel counterparts, indicating the need for exhaust gas after-treatment.