Inflammatory mediators induced by coarse (PM2.5-10) and fine (PM2.5) urban air particles in RAW 264.7 cells

Use of human airway smooth muscle in vitro and ex vivo to investigate drugs for the treatment of chronic obstructive respiratory disorders

Isolated airway smooth muscle has been extensively investigated since 1840 to understand the pharmacology of airway diseases. There has often been poor predictability from murine experiments to drugs evaluated in patients with asthma or chronic obstructive pulmonary disease (COPD). However, the use of isolated human airways represents a sensible strategy to optimise the development of innovative molecules for the treatment of respiratory diseases. This review aims to provide updated evidence on the current uses of isolated human airways in validated in vitro methods to investigate drugs in development for the treatment of chronic obstructive respiratory disorders. This review also provides historical notes on the pioneering pharmacological research on isolated human airway tissues, the key differences between human and animal airways, as well as the pivotal differences between human medium bronchi and small airways. Experiments carried out with isolated human bronchial tissues in vitro and ex vivo replicate many of the main anatomical, pathophysiological, mechanical and immunological characteristics of patients with asthma or COPD. In vitro models of asthma and COPD using isolated human airways can provide information that is directly translatable into humans with obstructive lung diseases. Regardless of the technique used to investigate drugs for the treatment of chronic obstructive respiratory disorders (i.e., isolated organ bath systems, videomicroscopy and wire myography), the most limiting factors to produce high-quality and repeatable data remain closely tied to the manual skills of the researcher conducting experiments and the availability of suitable tissue.

Causal effects of exposure to ambient air pollution on cancer risk: Insights from genetic evidence

Air pollution has been increasingly linked to cancer risk. However, the genetic causality between air pollution and cancer risk remains poorly understood. To elucidate the potential roles of air pollution (NOx, NO2, PM2.5, PM course, and PM10) in the risk of 18 specific-site cancers, large-scale genome-wide association studies with a novel Mendelian randomization (MR) method were employed. Our MR analyses revealed significant associations between certain air pollutants and specific types of cancer. Specifically, a positive association was observed between NOx exposure and squamous cell lung cancer (OR: 1.96, 95%CI: 1.07-3.59, p = 0.03) as well as esophageal cancer (OR: 1.002, 95%CI: 1.001-1.003, p = 0.005). Genetically predicted NO2 exposure was found to be a risk factor for endometrial cancer (OR 1.41, 95%CI: 1.03-1.94, p = 0.03) and ovarian cancer (OR: 1.49, 95%CI: 1.14-1.95, p = 0.0037). Additionally, genetically predicted PM2.5 exposure was associated with an increased risk of ER+ breast cancer (OR: 1.24, 95%CI: 1.03-1.5, p = 0.02) and ER- breast cancer (OR: 2.57, 95%CI: 1.05-6.3, p = 0.04). PM course exposure was identified as a risk factor for glioma (OR: 487.28, 95%CI: 13.08-18,153, p = 0.0008), while PM10 exposure exerted a detrimental effect on mesothelioma (OR: 114.75, 95%CI: 1.14-11,500.11, p = 0.04) and esophageal cancer (OR: 1.01, 95%CI: 1.007-1.02, p = 0.03). These findings underscored the importance of mitigating air pollution to reduce the burden of cancer and highlight the need for further investigations to elucidate the underlying mechanisms involved in these associations.

Coarse Particulate Matter and Markers of Inflammation and Coagulation in the Multi-Ethnic Study of Atherosclerosis (MESA) Population: A Repeat Measures Analysis

BACKGROUND

In contrast to fine particles, less is known of the inflammatory and coagulation impacts of coarse particulate matter (PM 10 - 2.5 , particulate matter with aerodynamic diameter ≤ 10 μ m  and > 2.5 μ m ). Toxicological research suggests that these pathways might be important processes by which PM 10 - 2.5 impacts health, but there are relatively few epidemiological studies due to a lack of a national PM 10 - 2.5 monitoring network.

OBJECTIVES

We used new spatiotemporal exposure models to examine associations of both 1-y and 1-month average PM 10 - 2.5 concentrations with markers of inflammation and coagulation.

METHODS

We leveraged data from 7,071 Multi-Ethnic Study of Atherosclerosis and ancillary study participants 45-84 y of age who had repeated plasma measures of inflammatory and coagulation biomarkers. We estimated PM 10 - 2.5 at participant addresses 1 y and 1 month before each of up to four exams (2000-2012) using spatiotemporal models that incorporated satellite, regulatory monitoring, and local geographic data and accounted for spatial correlation. We used random effects models to estimate associations with interleukin-6 (IL-6), C-reactive protein (CRP), fibrinogen, and D-dimer, controlling for potential confounders.

RESULTS

Increases in PM 10 - 2.5 were not associated with greater levels of inflammation or coagulation. A 10 - μ g / m 3 increase in annual average PM 10 - 2.5 was associated with a 2.5% decrease in CRP [95% confidence interval (CI): - 5.5 , 0.6]. We saw no association between annual average PM 10 - 2.5 and the other markers (IL-6: - 0.7 % , 95% CI: - 2.6 , 1.2; fibrinogen: - 0.3 % , 95% CI: - 0.9 , 0.3; D-dimer: - 0.2 % , 95% CI: - 2.6 , 2.4). Associations consistently showed that a 1 0 - μ g / m 3 increase in 1-month average PM 10 - 2.5 was associated with reduced inflammation and coagulation, though none were distinguishable from no association (IL-6: - 1.2 % , 95% CI: - 3.0   , 0.5; CRP: - 2.5 % , 95% CI: - 5.3 , 0.4; fibrinogen: - 0.4 % , 95% CI: - 1.0 , 0.1; D-dimer: - 2.0 % , 95% CI: - 4.3 , 0.3).

DISCUSSION

We found no evidence that PM 10 - 2.5 is associated with higher inflammation or coagulation levels. More research is needed to determine whether the inflammation and coagulation pathways are as important in explaining observed PM 10 - 2.5 health impacts in humans as they have been shown to be in toxicology studies or whether PM 10 - 2.5 might impact human health through alternative biological mechanisms. https://doi.org/10.1289/EHP12972.

Effect of E. cava and C. indicum Complex Extract on Phorbol 12-Myristate 13-Acetate (PMA)-Stimulated Inflammatory Response in Human Pulmonary Epithelial Cells and Particulate Matter (PM)2.5-Induced Pulmonary Inflammation in Mice

This study explores the potential of a natural composite formulation known as ED, consisting of Ecklonia cava (E. cava, family: Lessoniaceae) and Chrysanthemum indicum Linne (C. indicum, family: Asteraceae), in alleviating lung inflammation induced by fine particulate matter (PM2.5). Initial assessments confirmed that neither ED nor one of its components, dieckol, exhibited cytotoxic effects on A549 cells. Subsequently, the impact of ED and dieckol on MUC5AC gene expression in A549 cells stimulated by phorbol 12-myristate 13-acetate (PMA) was investigated, revealing promising results that demonstrated a dose-dependent inhibition of MUC5AC gene expression. The study also delves into the underlying mechanisms, demonstrating that ED and dieckol effectively suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs), including JNK, ERK, and p38, which are known to be involved in the regulation of MUC5AC gene expression. In in vivo experiments using a PM2.5-induced pulmonary inflammation mouse model, the research findings showed that ED mitigated cellular accumulation in the airways, leading to a significant reduction in the total cell count in bronchoalveolar lavage fluid (BALF). Moreover, ED exhibited protective effects against PM2.5-induced pulmonary damage, characterized by reduced inflammatory cell infiltration and decreased mucus secretion in pulmonary tissues. Additionally, ED's anti-inflammatory properties were evident in its ability to decrease the levels of key inflammatory cytokines, TNF-α and IL-6, both in the serum and lung tissue of the PM2.5-induced pulmonary inflammation mouse model. These findings suggest the potential of ED as a therapeutic agent for inflammatory respiratory diseases.

An integrative analysis of lipidomics and transcriptomics in various mouse brain regions in response to real-ambient PM2.5 exposure

Exposure to Fine particulate matter (PM2.5) has been associated with various neurological disorders. However, the underlying mechanisms of PM2.5-induced adverse effects on the brain are still not fully defined. Multi-omics analyses could offer novel insights into the mechanisms of PM2.5-induced brain dysfunction. In this study, a real-ambient PM2.5 exposure system was applied to male C57BL/6 mice for 16 weeks, and lipidomics and transcriptomics analysis were performed in four brain regions. The findings revealed that PM2.5 exposure led to 548, 283, 304, and 174 differentially expressed genes (DEGs), as well as 184, 89, 228, and 49 distinctive lipids in the hippocampus, striatum, cerebellum, and olfactory bulb, respectively. Additionally, in most brain regions, PM2.5-induced DEGs were mainly involved in neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction, and calcium signaling pathway, while PM2.5-altered lipidomic profile were primarily enriched in retrograde endocannabinoid signaling and biosynthesis of unsaturated fatty acids. Importantly, mRNA-lipid correlation networks revealed that PM2.5-altered lipids and DEGs were obviously enriched in pathways involving in bile acid biosynthesis, De novo fatty acid biosynthesis, and saturated fatty acids beta-oxidation in brain regions. Furthermore, multi-omics analyses revealed that the hippocampus was the most sensitive part to PM2.5 exposure. Specifically, dysregulation of Pla2g1b, Pla2g, Alox12, Alox15, and Gpx4 induced by PM2.5 were closely correlated to the disruption of alpha-linolenic acid, arachidonic acid and linoleic acid metabolism in the hippocampus. In summary, our findings highlight differential lipidomic and transcriptional signatures of various brain regions by real-ambient PM2.5 exposure, which will advance our understanding of potential mechanisms of PM2.5-induecd neurotoxicity.

Role of different mechanisms in pro-inflammatory responses triggered by traffic-derived particulate matter in human bronchiolar epithelial cells

BACKGROUND

Traffic-derived particles are important contributors to the adverse health effects of ambient particulate matter (PM). In Nordic countries, mineral particles from road pavement and diesel exhaust particles (DEP) are important constituents of traffic-derived PM. In the present study we compared the pro-inflammatory responses of mineral particles and DEP to PM from two road tunnels, and examined the mechanisms involved.

METHODS

The pro-inflammatory potential of 100 µg/mL coarse (PM10-2.5), fine (PM2.5-0.18) and ultrafine PM (PM0.18) sampled in two road tunnels paved with different stone materials was assessed in human bronchial epithelial cells (HBEC3-KT), and compared to DEP and particles derived from the respective stone materials. Release of pro-inflammatory cytokines (CXCL8, IL-1α, IL-1β) was measured by ELISA, while the expression of genes related to inflammation (COX2, CXCL8, IL-1α, IL-1β, TNF-α), redox responses (HO-1) and metabolism (CYP1A1, CYP1B1, PAI-2) was determined by qPCR. The roles of the aryl hydrocarbon receptor (AhR) and reactive oxygen species (ROS) were examined by treatment with the AhR-inhibitor CH223191 and the anti-oxidant N-acetyl cysteine (NAC).

RESULTS

Road tunnel PM caused time-dependent increases in expression of CXCL8, COX2, IL-1α, IL-1β, TNF-α, COX2, PAI-2, CYP1A1, CYP1B1 and HO-1, with fine PM as more potent than coarse PM at early time-points. The stone particle samples and DEP induced lower cytokine release than all size-fractionated PM samples for one tunnel, and versus fine PM for the other tunnel. CH223191 partially reduced release and expression of IL-1α and CXCL8, and expression of COX2, for fine and coarse PM, depending on tunnel, response and time-point. Whereas expression of CYP1A1 was markedly reduced by CH223191, HO-1 expression was not affected. NAC reduced the release and expression of IL-1α and CXCL8, and COX2 expression, but augmented expression of CYP1A1 and HO-1.

CONCLUSIONS

The results indicate that the pro-inflammatory responses of road tunnel PM in HBEC3-KT cells are not attributed to the mineral particles or DEP alone. The pro-inflammatory responses seem to involve AhR-dependent mechanisms, suggesting a role for organic constituents. ROS-mediated mechanisms were also involved, probably through AhR-independent pathways. DEP may be a contributor to the AhR-dependent responses, although other sources may be of importance.

Potential Biological Mediators of Myocardial and Vascular Complications of Air Pollution-A State-of-the-Art Review

Ambient air pollution is recognised globally as a significant contributor to the burden of cardiovascular diseases. The evidence from both human and animal studies supporting the cardiovascular impact of exposure to air pollution has grown substantially, implicating numerous pathophysiological pathways and related signalling mediators. In this review, we summarise the list of activated mediators for each pathway that lead to myocardial and vascular injury in response to air pollutants. We performed a systematic search of multiple databases, including articles between 1990 and Jan 2022, summarising the evidence for activated pathways in response to each significant air pollutant. Particulate matter <2.5 μm (PM_2.5) was the most studied pollutant, followed by particulate matter between 2.5 μm-10 μm (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃). Key pathogenic pathways that emerged included activation of systemic and local inflammation, oxidative stress, endothelial dysfunction, and autonomic dysfunction. We looked at how potential mediators of each of these pathways were linked to both cardiovascular disease and air pollution and included the overlapping mediators. This review illustrates the complex relationship between air pollution and cardiovascular diseases, and discusses challenges in moving beyond associations, towards understanding causal contributions of specific pathways and markers that may inform us regarding an individual's exposure, response, and likely risk.

Fine-Dust-Induced Skin Inflammation: Low-Molecular-Weight Fucoidan Protects Keratinocytes and Underlying Fibroblasts in an Integrated Culture Model

Prolonged exposure to fine dust (FD) increases the risk of skin inflammation. Stimulated epidermal cells release growth factors into their extracellular environment, which can induce inflammation in dermal cells. Algae are considered rich sources of bioactive materials. The present study emphasized the effect of low-molecular-weight fucoidan isolated from Sargassum confusum (LMF) against FD-induced inflammation in HaCaT keratinocytes and underneath fibroblasts (HDFs) in an integrated culture model. HDFs were treated with media from FD-stimulated HaCaT with LMF treatments (preconditioned media). The results suggested that FD increased the oxidative stress in HaCaT, thereby increasing the sub-G₁ phase of the cell cycle up to 587%, as revealed via flow cytometric analysis. With preconditioned media, HDFs also displayed oxidative stress; however, the increase in the sub-G₁ phase was insignificant compared with HaCaT. LMF dose-dependently regulated the NF-κB/MAPK signaling in HaCaT. Furthermore, significant downregulation in NF-κB/MAPK signaling, as well as inflammatory cytokines, tissue inhibitors of metalloproteinases, matrix metalloproteinases, and reduction in relative elastase and collagenase activities related to the extracellular matrix degeneration were observed in HDFs with a preconditioned media treatment. Therefore, we concluded that HDFs were protected from inflammation by preconditioned media. Continued research on tissue culture and in vivo studies may reveal the therapeutic potential of LMF.

The Lipid Profile and Biochemical Parameters of COPD Patients in Relation to Smoking Status

Tobacco consumption is the most incriminated and studied risk factor for Chronic obstructive pulmonary disease (COPD), but other factors such as air pollution, are also linked to this disease. One of the known aspects of this chronic lung disease is that its occurrence is mainly due to the chronic inflammation of the airways. Lipid metabolism seems to be affected by smoking, with studies showing a correlation between this habit and high levels of triglycerides and low levels of high-density lipoprotein cholesterol (HDL-CHOL). Uric acid concentration is thought to reflect the antioxidative capacity of the body because it is the most abundant aqueous antioxidant. The aim of this study was to investigate the lipid profile and biochemical parameters of COPD patients in relation to smoking status. The present study was conducted between 2020 and 2021 in the Clinical Hospital of Pneumology in Iasi, Romania. Patients diagnosed with COPD (n = 52) were included and divided in three groups depending on their smoking status: non-smokers, smokers and ex-smokers. The obtained results show low correlations between COPD stages and serum uric acid concentrations (r = 0.4; p ˂ 0.05), smoking status (smoker/non-smoker/ex-smoker) and total serum cholesterol values (r = 0.45; p ˂ 0.05), but also between serum urea concentrations and the number of packs-years for the smoker/ex-smoker groups (r = 0.45, p ˂ 0.05). Smoking was associated with changes in the lipid profile of smokers and ex-smokers, along with increased low-density lipoprotein cholesterol (LDL-CHOL) and low serum uric acid values.

The efficacy, effectiveness, and safety of Kyung-ok-ko: A narrative review

Kyung-ok-ko (KOK), a traditional medicinal formula in East Asia, has been recently studied across various fields. However, comprehensive reviews of clinical applications of KOK targeting clinical and experimental studies are lacking. Therefore, the application of KOK is being limited to the range of tonic medicines. To overcome this limitation, we aim to investigate the effectiveness, mechanism, and safety of KOK to obtain evidence regarding its effects in clinical applications. We searched for clinical and experimental articles in 11 databases (PubMed, Cochrane Library, Excerpta Medica dataBASE, China National Knowledge Infrastructure, Google Scholar, Research Information Sharing Service, Oriental Medicine Advanced Searching Integrated System, Koreanstudies Information Service System, Korean Medical Database, DBpia, and ScienceON). We selected 54 studies based on the inclusion criteria. Three clinical studies used KOK for a consumptive disease and health promotion. Fifty-one experimental studies reported the antioxidant activity, neuroprotective activity, anticancer effect, anti-inflammatory activity, immunological activity, growth promotion, impacts on cardiovascular system diseases, gastrointestinal system diseases, respiratory system diseases, and metabolic bone disease, hepatoprotective function, and antifatigue function of KOK, which were considered effective and safe in consumptive, chronic, metabolic, inflammatory, and immune diseases. We identified the effectiveness of KOK in the treatment of a wide range of diseases. However, further clinical studies are warranted in the future.

Status of TNF-α and IL-6 as pro-inflammatory cytokines in exhaled breath condensate of late adolescents with asthma and healthy in the dust storm and non-dust storm conditions

Exposure to airborne particulate matter (PM) can be considered as an important risk factor for human health. Some cytokines have been recognized as the biomarkers of exposure to air pollution. Experimental studies indicate that PM exposure could be associated with inflammation. Thus, the purpose of this study was to evaluate whether the exposure to air PM is associated with biomarkers of inflammation. The specific aim of this study was to determine the correlation between airborne PM levels and IL-6 and TNF-α as airway inflammation biomarkers among two groups of late adolescents in northwest of Iran. This study included 46 subjects, comprising 23 asthmatic subjects and 23 non-asthmatic persons. Environmental PM (PM₁₀, PM_2.5 and PM₁) levels were measured in dust storm and non-dust storm days during both cold and warm seasons. Following the sampling of PM, Two pro-inflammatory cytokines of IL-6 and TNF-α in exhaled breath condensate (EBC) were also determined in the EBC samples via commercial ELISA kits. Daily mean ambient air PM₁₀, PM_2.5 and PM₁ concentrations during the dust storm days was 221.79, 93.13 and 25.52 μg m^-3 and in non-dusty days 48.37, 18.54 and 6.1 μg m^-3, respectively. Biomarkers levels were significantly (p < 0.001) higher in asthmatic students compared to the non-asthmatic subjects. EBC cytokines levels were increased in dust storm days compared to the non-dusty days (p < 0.001) and were positively correlated with different size of ambient PM concentration. Dust storm conditions can increase the pro-inflammatory cytokines and cause adverse effects on pulmonary health and lung tissue damage.

Characterization of Si and SiO2 in Dust Emitted during Granite Polishing as a Function of Cutting Conditions

Particles emitted during manufacturing processes such as polishing can represent a serious danger for the environment and for occupational safety. The formation mechanisms responsible for these dust emissions include chip formation, friction at the tool/workpiece and chip/tool interfaces, shearing and cutting. These mechanisms thus depend on workpiece and tool properties, as well as the polishing conditions. In the case of granite polishing, particle emissions during polishing can contain chemical compounds such as silica, which represent harmful health risks for the worker. It is therefore important to characterize the particles emitted and to search for possible interactions between the particles (size and composition) and the machining conditions in order to find ways of reducing emissions at the source. In this study, an investigation was undertaken to characterize the particles emitted during granite polishing as a function of polishing conditions, type of granite, and abrasive grit sizes used. Scanning electron microscopy (SEM) was employed for particle morphology characterization and particle grain size and chemical composition were evaluated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques, respectively. Results show that the influence of polishing speed and feed rate on particle emission depends mainly on the granite type used, providing useful information for controlling the polishing procedure, and thereby dust emission.

Association of short-term particulate matter exposure with suicide death among major depressive disorder patients: a time-stratified case-crossover analysis

There is growing evidence that suggests a potential association between particulate matter (PM) and suicide. However, it is unclear that PM exposure and suicide death among major depressive disorder (MDD) patients, a high-risk group for suicide. We aimed to assess the effect of short-term exposure to PM on the risk of suicide in MDD patients who are at high risk for suicide. We investigated the risk of suicide among 922,062 newly-diagnosed MDD patients from 2004 to 2017 within the Korean National Health Insurance Service (NHIS) database. We identified 3,051 suicide cases from January 1, 2015, to December 31, 2017, within the death statistics database of the Korean National Statistical Office. PMs with aerodynamic diameter less than 2.5 μm (PM2.5), less than 10 μm (PM10), and 2.5–10 μm (PM2.5–10) were considered, which were provided from the National Ambient Air Monitoring System in South Korea. Time-stratified case-crossover analysis was performed to investigate the association of particulate matter exposure to suicide events. The risk of suicide was significantly high upon the high level of exposure to PM2.5, PM2.5–10 (coarse particle) and PM10 on lag 1 (p for trend < 0.05). Short-term exposure to a high level of PM was associated with an elevated risk for suicide among MDD patients. There is a clear dose–response relationship between short-term PM exposures with suicide death among MDD patients. This result will be used as an essential basis for consideration when establishing an air pollution alarm system for reducing adverse health outcomes by PM.

Anti-Adhesive Properties of Calcium Alginate from Sargassum fusiforme against Particulate Matter-Induced Inflammation

Fine dust generated by particulate matter (PM) pollution is a serious ecological issue in industrialized countries and causes disorders of the respiratory system and skin in humans. In the previous study, Sargassum fusiforme was treated with citric acid to remove heavy metals. In this study, the transfer of PM-mediated inflammatory responses through the skin to macrophages was evaluated. Moreover, the anti-adhesive effects of calcium alginate isolated from S. fusiforme (SFCA) against PM-induced inflammation were investigated. The structures of processing and unprocessing SFCA were then analyzed by Fourier-transform infrared spectroscopy (FT-IR), revealing minimal change after acid-processing. SFCA had protective effects both in PM-stimulated HaCaT keratinocytes and RAW 264.7 macrophages. In cellular environments, it was found that SFCA attenuated signal protein expressions such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E₂ (PGE₂), and pro-inflammatory cytokines. Furthermore, macrophages were added to the culture medium of PM-stimulated keratinocytes to induce inflammation. SFCA was observed to significantly inhibit inflammatory responses; additionally, SFCA showed an in vivo anti-adhesive effect in zebrafish embryos.

Toxicology of respiratory system: Profiling chemicals in PM10 for molecular targets and adverse outcomes

Numerous studies have shown that the increasing trend of respiratory diseases have been closely associated with the endogenous toxic chemicals (polycyclic aromatic hydrocarbons, heavy metal ions, etc.) in PM₁₀. In the present study, we aim to determine the strong correlations between the chemicals in PM₁₀ and the adverse consequences. We used the ChemView DB, the ToxRef DB and a comprehensive literature analysis to collect, identify, and evaluate the chemicals in PM₁₀ and their adverse effects on respiratory system, and then used the ToxCast DB to analyze their bioactivity and key targets through 1192 molecular targets and cell characteristic endpoints. Meanwhile, the bioinformatics analysis were carried out on the molecular targets to screen out prevention and treatment targets. A total of 310 chemicals related to the respiratory system were identified. An unsupervised two-directional heatmap was constructed based on hierarchical clustering of 227 chemicals by their effect scores. A subset of 253 chemicals with respiratory system toxicity had in vitro bioactivity on 318 molecular targets that could be described, clustered and annotated in the heatmap and bipartite network, which were analyzed based on the protein information in UniProt KB database and the software of GO, STRING, and KEGG. These results showed that the chemicals in PM₁₀ have strong correlation with different types of respiratory system injury. The main pathways of respiratory system injury caused by PM₁₀ are the Calcium signaling pathway, MAPK signaling pathway, and PI3K-AKT signaling pathway, and the core proteins in which are likely to be the molecular targets for the prevention and treatment of damage caused by PM₁₀.

Protective effect of the effective part of Andrographis paniculata (Burm.f.) Nees on PM2.5-induced lung injury in rats by modulating the NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (Burm.f.) Nees, a traditional Chinese herb, has been widely used in various Asian countries as a treatment for upper respiratory tract infections for centuries.

AIM OF THE STUDY

Continuous inhalation of fine particulate matter (PM_2.5) may induce various respiratory diseases. This study elucidated the protective effect of the effective part of Andrographis paniculata (Burm.f.) Nees (AEP) against PM_2.5-induced lung injury and detailed the underlying mechanism.

MATERIALS AND METHODS

Male Wistar rats were orally administered 0.5% sodium carboxymethylcellulose (CMC-Na), andrographolide (AG) (200 mg/kg) and AEP (100 mg/kg, 200 mg/kg and 400 mg/kg) once a day for 28 days. The rats were intratracheally instilled with PM_2.5 suspension (8 mg/kg) every other day beginning on the 24th day for a total of 3 times. On the 29th day, bronchoalveolar lavage fluid (BALF) was collected to analyze the levels of lactate dehydrogenase (LDH), acid phosphatase (ACP), alkaline phosphatase (AKP), total proteins (TP), tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6). Hematoxylin & eosin staining was conducted to evaluate the pathological changes in the lung tissues. The protein expression of NF-κB p65 in the lung tissues was analyzed by immunohistochemistry staining. Moreover, the nuclear translocation of NF-κB p65 and the phosphorylation of IκBα were analyzed by western blotting.

RESULTS

PM_2.5 exposure caused lung toxicity, which was characterized by pathological injury and increased levels of LDH, ACP, AKP and TP in BALF. Meanwhile, PM_2.5 exposure induced lung inflammatory response, including infiltration of inflammatory cells and increased levels of inflammatory factors, such as TNF-α and IL-6 in BALF. AEP treatment significantly ameliorated the PM_2.5-induced lung toxicity and the inflammatory response in rats. Moreover, AEP significantly inhibited the PM_2.5-induced upregulation of NF-κB p65 protein expression, phosphorylation of IκBα and nuclear translocation of NF-κB p65 in lung tissue. Compared to AG, AEP exhibited a better ability to alleviate PM_2.5-induced pathological damage and decrease the TP level in the BALF.

CONCLUSION

AEP could be used to improve PM_2.5-induced lung injury by modulating the NF-κB pathway, and multicomponent therapy with traditional Chinese medicine may be more effective than single-drug therapy.

Genomic Approach to the Assessment of Adverse Effects of Particulate Matters on Skin Cancer and Other Disorders and Underlying Molecular Mechanisms

Air pollutants are in the spotlight because the human body can easily be exposed to them. Among air pollutants, the particulate matter (PM) represents one of the most serious toxicants that can enter the human body through various exposure routes. PMs have various adverse effects and classified as severe carcinogen by International Agency for Research on Cancer. Their physical and chemical characteristics are distinguished by their size. In this review, we summarized the published information on the physicochemical characteristics and adverse effects of PMs on the skin, including carcinogenicity. Through comparisons of biological networks constructed from relationships discussed in the previous scientific publications, we show it is possible to predict skin cancers and other disorders from particle-size-specific signaling alterations of PM-responsive genes. Our review not only helps to grasp the biological association between ambient PMs and skin diseases including cancer, but also provides new approaches to interpret chemical-gene-disease associations regarding the adverse effects of these heterogeneous particles.

Taurine reduction associated with heart dysfunction after real-world PM2.5 exposure in aged mice

Ambient PM_2.5 has been proved to be an independent risk factor for cardiovascular diseases; however, little information is available on the age-dependent effects of PM_2.5 on the cardiovascular system and the underlying mechanisms following chronic exposure. In this study, multi-aged mice were exposed to PM_2.5 via the newly developed real-ambient PM_2.5 exposure system to investigate age-related effects on the heart after long-term exposure. First, the chemical and physical properties of PM_2.5 used in the exposure system were analyzed. The heart rate of conscious mice was recorded, and results showed that exposure of aged mice to PM_2.5 for 26 weeks significantly increased heart rate. Histological analysis and ELISA assays indicated that aged mice were more sensitive to PM_2.5 exposure in terms of inducing cardiac oxidative stress and inflammation. Furthermore, untargeted metabolomics revealed that taurine was involved with the PM_2.5-induced cardiac dysfunction. The reduced taurine concentration in the heart was examined by LC-MS and imaging mass spectrometry; it may be due to the increased p53 expression level, ROS and inflammatory cytokines. These results emphasize the age-dependent effects of PM_2.5 on the cardiovascular system and suggest that taurine may be the novel cardiac effect target for PM_2.5-induced heart dysfunction in the aged.

Algae-Derived Anti-Inflammatory Compounds against Particulate Matters-Induced Respiratory Diseases: A Systematic Review

Air pollution has recently become a subject of increasing concern in many parts of the world. The World Health Organization (WHO) estimated that nearly 4.2 million early deaths are due to exposure to fine particles in polluted air, which causes multiple respiratory diseases. Algae, as a natural product, can be an alternative treatment due to potential biofunctional properties and advantages. This systematic review aims to summarize and evaluate the evidence of metabolites derived from algae as potential anti-inflammatory agents against respiratory disorders induced by atmospheric particulate matter (PM). Databases such as Scopus, Web of Science, and PubMed were systematically searched for relevant published full articles from 2016 to 2020. The main key search terms were limited to "algae", "anti-inflammation", and "air pollutant". The search activity resulted in the retrieval of a total of 36 publications. Nine publications are eligible for inclusion in this systematic review. A total of four brown algae (Ecklonia cava, Ishige okamurae, Sargassum binderi and Sargassum horneri) with phytosterol, polysaccharides and polyphenols were reported in the nine studies. The review sheds light on the pathways of particulate matter travelling into respiratory systems and causing inflammation, and on the mechanisms of actions of algae in inhibiting inflammation. Limitations and future directions are also discussed. More research is needed to investigate the potential of algae as anti-inflammatory agents against PM in in vivo and in vitro experimental models, as well as clinically.

Influence of fine particulate matter and its pure particulate fractions on pulmonary immune cells and cytokines in mice

Particulate matter with a diameter ≤2.5 µm (PM^2.5) has a complex composition and has been associated with the incidence of cardiopulmonary disease and premature death in humans. However, whether pure particulate fractions of PM^2.5 (PPP^2.5), which are composed primarily of carbon, are responsible for the toxicity caused by ambient particulate matter (original PM^2.5 particles, OPP^2.5) is currently unclear. The present study assessed the acute toxic effects of OPP^2.5 sampled in Beijing, China and of its PPP^2.5 fraction in male BALB/c mice. The mice were intratracheally instilled with a single dose of aerosolized OPP^2.5 or PPP^2.5. Blood, lungs and bronchoalveolar lavage fluid were collected after 24 h for histopathology, flow cytometry and the measurement of pro-inflammatory cytokines/chemokines and other biochemical factors. Both OPP^2.5 and PPP^2.5 caused acute toxicity, particularly inflammatory responses, including an increase in the levels of pro-inflammatory cytokines and an accumulation of numerous immune cells in the lungs. OPP^2.5 induced a stronger inflammatory response than PPP^2.5. The complex components adsorbed into the solid core granules of OPP^2.5 and the granules themselves contributed to the toxic effects.

Inhibitory effects of cudratricusxanthone O on particulate matter-induced pulmonary injury

Particulate matter 2.5 (PM_2.5), aerodynamic diameter ≤ 2.5 μm, is the primary air pollutant that plays the key role for lung injury resulted from the loss of vascular barrier integrity. Cudratricusxanthone O (CTXO) is a novel xanthone compound isolated from the root of Cudrania tricuspidata Bureau. Here, we investigated the beneficial effects of CTXO against PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated ECs and mice. CTXO significantly scavenged PM_2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase (MAPK). Concurrently, CTXO activated Akt, which helped maintain endothelial integrity. Furthermore, CTXO reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid in PM-induced lung tissues. These results indicated that CTXO may exhibit protective effects against PM-induced inflammatory lung injury and vascular hyperpermeability.

Fucoxanthin-rich fraction from Sargassum fusiformis alleviates particulate matter-induced inflammation in vitro and in vivo

Particulate matter (PM) contributes to air pollution and primarily originates from unregulated industrial emissions and seasonal natural dust emissions. Fucoxanthin (Fx) is a marine natural pigment from brown macroalgae that has been shown to have various beneficial effects on health. However, the effects of Fx on PM-induced toxicities in cells and animals have not been assessed. In this study, we investigated the anti-inflammatory potential of the Fx-rich fraction (FxRF) of Sargassum fusiformis against PM-mediated inflammatory responses. The FxRF composition was analyzed by rapid-resolution liquid chromatography mass spectrometry. Fx and other main pigments were identified. FxRF attenuated the production of inflammatory components, including prostaglandin E2 (PGE2), cyclooxygenase-2, interleukin (IL)-1β, and IL-6 from PM-exposed HaCaT keratinocytes. PM exposure also reduced the levels of nitric oxide (NO), tumor necrosis factor-α, inducible nitric oxide synthase (iNOS), and PGE2 in PM-exposed RAW264.7 macrophages. Additionally, the culture medium from PM-exposed HaCaT cells induced upregulation of NO, iNOS, PGE2, and pro-inflammatory cytokines in RAW264.7 macrophages. FxRF also significantly decreased the expression levels of factors involved in inflammatory responses, such as NO, reactive oxygen species, and cell death, in PM-exposed zebrafish embryos. These results demonstrated the potential protective effects of FxRF against PM-induced inflammation both in vitro and in a zebrafish model.

Indoor, outdoor, and personal exposure to PM2.5 and their bioreactivity among healthy residents of Hong Kong

Direct evidence about associations between fine particles (PM_2.5) components and the corresponding PM_2.5 bioreactivity at the individual level is limited. We conducted a panel study with repeated personal measurements involving 56 healthy residents in Hong Kong. Fractional exhaled nitric oxide (FeNO) levels were measured from these subjects. Out of 56 subjects, 27 (48.2%) participated in concurrent outdoor, indoor, and personal PM_2.5 monitoring. Organic carbon (OC), elemental carbon (EC), particle bound-polycyclic aromatic hydrocarbons (PAHs), and phthalates were analyzed. Alteration in cell viability, lactic dehydrogenase (LDH), interleukin-6 (IL-6), and 8-isoprostane by 50 μg/mL PM_2.5 extracts was determined in A549 cells in vitro. Moderate heterogeneities were shown in PM_2.5 exposures and the corresponding PM_2.5 bioreactivity across different sample types. Associations between the analyzed components and PM_2.5 bioreactivity were assessed using the multiple regression models. Toxicological results revealed that indoor and personal exposure to OC as well as PAH compounds and their derivatives (e.g., Alkyl-PAHs, Oxy-PAHs) induced cell viability reduction and increase in levels of LDH, IL-6, and 8-isoprostane. Overall, OC in personal exposure played a dominant role in PM_2.5-induced bioreactivity. Subsequently, we examined the associations of FeNO with IL-6 and 8-isoprostane levels using mixed-effects models. The results showed that per interquartile change in IL-6 and 8-isoprostane were associated with a 6.4% (p < 0.01) and 11.1% (p < 0.01) increase in FeNO levels, respectively. Our study explored the toxicological properties of chemical components in PM_2.5 exposure, which suggested that residential indoors and personal OC and PAHs should be of great concern for human health. These findings indicated that further studies in inflammation and oxidative stress-related illnesses due to particle exposure would benefit from the assessment of in vitro PM_2.5 bioreactivity.

Autophagy changes in lung tissues of mice at 30 days after carbon black-metal ion co-exposure

OBJECTIVES

Accumulating studies have investigated the PM2.5-induced pulmonary toxicity, while gaps still remain in understanding its toxic mechanism. Due to its high specific surface area and adsorption capacity similar to nanoparticles, PM2.5 acts as a significant carrier of metals in air and then leads to altered toxic effects. In this study, we aimed to use CBs and Ni as model materials to investigate the autophagy changes and pulmonary toxic effects at 30 days following intratracheal instillation of CBs-Ni mixture.

MATERIALS AND METHODS

Groups of mice were instilled with 100 µL normal saline (NS), 20 µg CBs, and 4 µg Ni or CBs-Ni mixture, respectively. At 7 and 30 days post-instillation, all the mice were weighed and then sacrificed. The evaluation system was composed of the following: (a) autophagy and lysosomal function assessment, (b) trace element biodistribution observation in lungs, (c) pulmonary lavage biomedical analysis, (d) lung histopathological evaluation, (e) coefficient analysis of major organs and (f) CBs-Ni interaction and cell proliferation assessment.

RESULTS

We found that after CBs-Ni co-exposure, no obvious autophagy and lysosomal dysfunction or pulmonary toxicity was detected, along with complete clearance of Ni from lung tissues as well as recovery of biochemical indexes to normal range.

CONCLUSIONS

We conclude that the damaged autophagy and lysosomal function, as well as physiological function, was repaired at 30 days after exposure of CBs-Ni. Our findings provide a new idea for scientific assessment of the impact of fine particles on environment and human health, and useful information for the comprehensive treatment of air pollution.

Fifteen Years of Airborne Particulates in Vitro Toxicology in Milano: Lessons and Perspectives Learned

Air pollution is one of the world’s leading environmental causes of death. The epidemiological relationship between outdoor air pollution and the onset of health diseases associated with death is now well established. Relevant toxicological proofs are now dissecting the molecular processes that cause inflammation, reactive species generation, and DNA damage. In addition, new data are pointing out the role of airborne particulates in the modulation of genes and microRNAs potentially involved in the onset of human diseases. In the present review we collect the relevant findings on airborne particulates of one of the biggest hot spots of air pollution in Europe (i.e., the Po Valley), in the largest urban area of this region, Milan. The different aerodynamic fractions are discussed separately with a specific focus on fine and ultrafine particles that are now the main focus of several studies. Results are compared with more recent international findings. Possible future perspectives of research are proposed to create a new discussion among scientists working on the toxicological effects of airborne particles.

Indoor PM2.5, tobacco smoking and chronic lung diseases: A narrative review

The lung is one of the most important organs exposed to environmental agents. People spend approximately 90% of their time indoors, and risks to health may thus be greater from exposure to poor air quality indoors than outdoors. Multiple indoor pollutants have been linked to chronic respiratory diseases. Environmental tobacco smoke (ETS) is known as an important source of multiple pollutants, especially in indoor environments. Indoor PM_2.5 (particulate matter with aerodynamic diameter < 2.5 μm) was reported to be the most reliable marker of the presence of tobacco smoke. Recent studies have demonstrated that PM_2.5 is closely correlated with chronic lung diseases. In this paper, we reviewed the relationship of tobacco smoking and indoor PM_2.5 and the mechanism that underpin the link of tobacco smoke, indoor PM_2.5 and chronic lung diseases.

Particulate Matter Increases the Severity of Bleomycin-Induced Pulmonary Fibrosis through KC-Mediated Neutrophil Chemotaxis

Background: Although particular matter (PM) increases incidence and severity of idiopathic pulmonary fibrosis, the underlying mechanism remains elusive. Methods: The effects of PM were evaluated in a murine model of bleomycin-induced pulmonary fibrosis. Mice were divided into four groups, receiving: (1) Saline (control), (2) bleomycin, (3) PM, or (4) bleomycin plus PM (Bleo+PM). Additional groups of Bleo+PM mice were treated with sivelestat (an inhibitor of neutrophil elastase) or reparixin (a C-X-C motif chemokine receptor 2 antagonist), or were genetically modified with keratinocyte chemoattractant (KC) deletion. Results: Pulmonary fibrosis was not observed in the control or PM groups. Bleomycin induced pulmonary fibrosis within 14 days. The Bleo+PM group showed worse pulmonary fibrosis when compared to the bleomycin group. Analyses of immune cell profile and chemokine/cytokine concentrations at day 2-bronchoalveolar lavage fluid (BALF) revealed that the Bleo+PM group had increased neutrophil number and elastase level and KC concentration compared to the bleomycin group. Neutrophil elastase activated the Smad2/Smad3/α-SMA pathway to induce collagen deposition, while sivelestat abrogated the increased severity of pulmonary fibrosis caused by PM. Chemotaxis assay revealed that BALF of the Bleo+PM group recruited neutrophil, which was dependent on KC. Further, genetic KC deletion or pharmaceutical inhibition of KC binding to CXCR2 with reparixin ameliorated the PM-induced increased severity of pulmonary fibrosis. Conclusions: These data provide evidence that the PM-induced increased severity of pulmonary fibrosis depends on KC-mediated neutrophil chemotaxis and give additional mechanic insight that will aid in the development of therapeutic strategies.

The protective effect of Sargassum horneri against particulate matter-induced inflammation in lung tissues of an in vivo mouse asthma model

Sargassum horneri is an edible brown seaweed with potential anti-inflammatory properties. The present study was designed to evaluate the anti-inflammatory properties of S. horneri using an in vivo mouse asthma model following exposure to particulate matter (PM). 7-8 week old BALB/c mice (20-25 g) were randomly divided into seven groups (n = 4) as follows: 1: no treatment, 2: OVA (ovalbumin) + PM, 3: OVA + PM + SHE (S. horneri ethanol extract) 200 mg kg-1, 4: OVA + PM + SHE 400 mg kg-1, 5: OVA + PM + prednisone 5 mg kg-1, 6: OVA only, and 7: PM only. All mice (except healthy controls) were sensitized on the first day by intraperitoneal injection of 10 μg OVA and 2 mg Al(OH)3 in 200 μL of saline. Starting from day 15, mice (except groups 1 and 6) were exposed to sonicated PM (5 mg m-3, 30 min day-1) through a nebulizer daily for 7 consecutive days. Mice exposed to PM and OVA showed up-regulated expression of MAPKs and pro-inflammatory cytokine production in the lungs. Furthermore, PM-exposed lungs had significantly reduced expression of Nrf2 and HO-1 genes. However, oral administration of the SHE reduced the phosphorylation levels of MAPKs, iNOS and COX2 expression levels, and mRNA expression levels of pro-inflammatory cytokines. In addition, SHE treated group mice had up-regulated anti-oxidant gene expression levels in the lungs compared to group 2. These findings demonstrate that oral administration of the SHE re-establishes PM-induced inflammation and oxidative stress in the lungs. Taken together, the SHE has therapeutic potential in preventing PM-induced inflammation and oxidative stress.

Seasonal Variations and Chemical Predictors of Oxidative Potential (OP) of Particulate Matter (PM), for Seven Urban French Sites

Epidemiological studies suggest that the main part of chronic effects from air pollution is likely to be linked with particulate matter (PM). Oxidative potential (OP) of PM is gaining strong interest as a promising health exposure metric. This study combined atmospheric detailed composition results obtained for seven different urban background environments over France to examine any possible common feature in OP seasonal variations obtained using two assays (acid ascorbic (AA) and dithiothreitol (DTT)) along a large set of samples ( N > 700 ). A remarkable homogeneity in annual cycles was observed with a higher OP activity in wintertime at all investigated sites. Univariate correlations were used to link the concentrations of some major chemical components of PM and their OP. Four PM components were identified as OP predictors: OC, EC, monosaccharides and Cu. These species are notably emitted by road transport and biomass burning, targeting main sources probably responsible for the measured OP activity. The results obtained confirm that the relationship between OP and atmospheric pollutants is assay- and location-dependent and, thus, the strong need for a standardized test, or set of tests, for further regulation purposes.

Inhibitory Effects of Black Ginseng on Particulate Matter-Induced Pulmonary Injury

Inhalation of fine particulate matter (PM2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. Black ginseng (BG), steamed and dried ginseng nine times, exhibits various pharmacological activities such as antibacterial, antihyperglycemic, anti-atopic, antibacterial, and anti-inflammatory activities. In this study, we investigated the beneficial effects of black ginseng extract (BGE) against PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM2.5-treated ECs and mice. BGE significantly scavenged PM2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase (MAPK). Concurrently, BGE activated Akt, which helped maintain endothelial integrity. Furthermore, BGE reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid in PM-induced lung tissues. These results indicated that BGE may exhibit protective effects against PM-induced inflammatory lung injury and vascular hyperpermeability.

Inhibitory effects of collismycin C and pyrisulfoxin A on particulate matter-induced pulmonary injury

BACKGROUND

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. Marine microbial natural products isolated from microbial culture broths were screened for pulmonary protective effects against PM_2.5. Two 2,2'-bipyridine compounds isolated from a red alga-associated Streptomyces sp. MC025-collismycin C (2) and pyrisulfoxin A (5)-were found to inhibit PM_2.5-mediated vascular barrier disruption.

PURPOSE

To confirm the inhibitory effects of collismycin C and pyrisulfoxin A on PM_2.5-induced pulmonary injury STUDY DESIGN: In this study, we investigated the beneficial effects of collismycin C and pyrisulfoxin A on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation.

METHODS

Permeability, leukocyte migration, proinflammatory protein activation, reactive oxygen species (ROS) generation, and histology were evaluated in PM_2.5-treated ECs and mice.

RESULTS

Collismycin C and pyrisulfoxin A significantly scavenged PM_2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase as well as activated Akt, which helped in maintaining endothelial integrity, in purified pulmonary endothelial cells. Furthermore, collismycin C and pyrisulfoxin A reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid of PM-treated mice.

CONCLUSION

These data suggested that collismycin C and pyrisulfoxin A might exert protective effects on PM-induced inflammatory lung injury and vascular hyperpermeability.

Inhibitory effects of compounds isolated from Dioscorea batatas Decne peel on particulate matter-induced pulmonary injury in mice

Particulate matter 2.5 (PM_2.5), with an aerodynamic diameter of ≤2.5 μm, is the primary air pollutant that plays a key role associated with lung injury produced by loss of vascular barrier integrity. Dioscorea batatas Decne (Chinese yam), a perennial plant belonging to Dioscoreaceae family, is widely cultivated in tropical and subtropical regions across Asia. Both aerial parts and root of D. batatas are consumed for nutritional and medicinal purposes. The aim of this study was to (1) identify the bioactive compounds present in D. batatas peel which may be responsible for inhibition of PM_2.5-induced pulmonary inflammation in mice and (2) examine in vitro mechanisms underlying the observed effects of these compounds on mouse lung microvascular endothelial cells. The measured parameters include permeability, leukocyte migration, proinflammatory protein activation, reactive oxygen species (ROS) generation, and histology. Two phenanthrene compounds, 2,7-dihydroxy-4,6-dimethoxyphenanthrene (1) and 6,7-dihydroxy-2,4-dimethoxyphenanthrene (2) were isolated from D. batatas peels. Both these phenanthrene compounds exhibited significant scavenging activity against PM_2.5-induced ROS and inhibited ROS-induced activation of p38 mitogen-activated protein kinase. In addition, enhancement of Akt pathway, involved in the maintenance of endothelial integrity, was noted. These phenanthrene compounds also reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid obtained from PM_2.5-induced lung tissues. Evidence thus indicates that phenanthrene compounds derived from D. batatas may exhibit protective effects against PM_2.5-induced inflammatory lung injury and vascular hyperpermeability in mice.

Different biological effects of PM2.5 from coal combustion, gasoline exhaust and urban ambient air relate to the PAH/metal compositions

Few studies have compared the biological effects of PM_2.5 from coal combustion, gasoline exhaust and urban ambient air, and the roles of polycyclic aromatic hydrocarbons (PAHs) and metals playing in the process remain unclear. In this study, PM_2.5 samples from coal combustion, gasoline exhaust and urban ambient air were analyzed for 16 PAHs and 23 metals. Cytotoxic and inflammatory effects of different PM_2.5 were evaluated on differentiated THP-1 and A549 cells, respectively. We found that the coal combustion PM_2.5 samples induced stronger cytotoxic and inflammatory effects (p < 0.05). Pearson's correlation and principal component analysis showed that the PAHs containing four or more benzenoid rings and specific metals of cadmium, thallium, zinc and lead were positively related to the biological effects. Our results suggested that coal combustion PM_2.5 might be a more serious health hazard. Specific PAHs and metals might be account for the PM_2.5 induced biological effects.

Inhibitory effects of Kyung-Ok-Ko, traditional herbal prescription, on particulate matter-induced vascular barrier disruptive responses

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. A traditional herbal prescription, Kyung-Ok-Ko (KOK), has long been used in Oriental medicine as a tonic for age-related diseases. In this study, we investigated the beneficial effects of KOK on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated EC and mice. KOK significantly scavenged PM_2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase (MAPK). Concurrently, KOK activated Akt, which helped maintain endothelial integrity. Furthermore, KOK reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in bronchoalveolar lavage fluids in PM-induced lung tissues. These data suggested that KOK might exhibit protective effects in PM-induced inflammatory lung injury and vascular hyperpermeability.

Beijing urban particulate matter-induced injury and inflammation in human lung epithelial cells and the protective effects of fucosterol from Sargassum binderi (Sonder ex J. Agardh)

Particulate matter (PM) air pollution has gradually become a widespread problem in East Asia. PM may cause unfamiliar inflammatory responses, oxidative stress, and pulmonary tissue damage, and a comprehensive understanding of the underlying mechanisms is required in order to develop effective anti-inflammatory agents. In this study, fine dust collected from Beijing, China (CPM) (size < PM13 with majority < PM2.5) was evaluated for its oxidative stress- and inflammation-inducing effects, which cause cell damage, in A459 human lung epithelial cells. Oxidative stress was marked by an increase in intracellular ROS levels and the production of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and heme oxygenase-1 (HO-1). Upon induction of oxidative stress, a marked increase was observed in the expression of key inflammatory mediators such as COX-2 and PGE2 and the pro-inflammatory cytokines TNF-α and IL-6 via NF-kB and MAPK pathways. Cellular damage was marked by a reduction in viability, increased lactate dehydrogenase (LDH) release, formation of apoptotic and necrotic bodies, accumulation of sub-G1 phase cells, and DNA damage. Apoptosis was found to be mediated via the activation of caspases through the mitochondria-mediated pathway. Fucosterol, purified from the brown alga Sargassum binderi (Sonder ex J. Agardh) by bio-assay-guided fractionation and purification, exhibited potential therapeutic effects against CPM-induced detrimental effects. Further studies could focus on developing fucosterol, in forms such as steroidal inhalers, against PM-induced pulmonary tissue inflammation.

Association of particulate matter air pollution and hospital visits for respiratory diseases: a time-series study from China

Fine particulate matter (PM_2.5) is a mixture of multiple components, which is associated with several chronic diseases, including respiratory and cardiovascular diseases. We evaluated the association between daily PM_2.5 and PM_2.5-10 exposure and hospital visits for respiratory diseases. Hospital visits for respiratory diseases were collected from Yinzhou Health Information System database. We used generalized additive models to examine the excess relative risk (ERR) and 95% confidence interval for hospital visits for respiratory diseases associated with each 10-μg/m³ increase in PM_2.5 and PM_2.5-10 concentration. Non-linear exposure-response relationship between PM exposure and hospital visits for respiratory diseases was evaluated by a smooth spline. The ERRs for hospital visits for respiratory diseases associated with a 10-μg/m³ increase in the 6-day cumulative average concentration of PM_2.5 and PM_2.5-10 were 5.40 (95% CI 2.32, 8.57) and 6.37% (95% CI 1.84, 11.10), respectively. The findings remained stable when we adjusted other gaseous air pollution. PM_2.5 and PM_2.5-10 were associated with the increased visits for the acute upper respiratory infection, pneumonia, asthma, and COPD. In this time-series study, we found a positive association between daily particulate matter exposure and hospital visits for respiratory diseases.

Inhibitory effects of protopanaxatriol type ginsenoside fraction (Rgx365) on particulate matter-induced pulmonary injury

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury attributed to the loss of vascular barrier integrity. Black ginseng (BG), steamed 9 times and dried ginseng, and its major protopanaxatriol type ginsenosides (ginsenoside Rg4, Rg6, Rh4, Rh1, and Rg2) exhibited various biological activities including anti-septic, anti-diabetic, wound healing, immune-stimulatory, and anti-antioxidant activity. The aim of this study was to investigate the beneficial effects of Rgx365 (a protopanaxatriol type rare ginsenosides fraction) on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated EC and mice. Rgx365 significantly scavenged PM_2.5-induced ROS, inhibited ROS-induced activation of p38 mitogen-activated protein kinase (MAPK), activated Akt in purified pulmonary EC, which helped maintain endothelial integrity. Further, Rgx365 reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in bronchoalveolar lavage fluids in PM-induced mouse lung tissues. Data suggested that Rgx365 might exhibit protective effects in PM-induced inflammatory lung injury and vascular hyperpermeability.

Adverse Effects of Fine-Particle Exposure on Joints and Their Surrounding Cells and Microenvironment

Current understanding of the health risks and adverse effects upon exposure to fine particles is premised on the direct association of particles with target organs, particularly the lung; however, fine-particle exposure has also been found to have detrimental effects on sealed cavities distant to the portal-of-entry, such as joints. Moreover, the fundamental toxicological issues have been ascribed to the direct toxic mechanisms, in particular, oxidative stress and proinflammatory responses, without exploring the indirect mechanisms, such as compensated, adaptive, and secondary effects. In this Review, we recapitulate the current findings regarding the detrimental effects of fine-particle exposure on joints, the surrounding cells, and microenvironment, as well as their deteriorating impact on the progression of arthritis. We also elaborate the likely molecular mechanisms underlying the particle-induced detrimental influence on joints, not limited to direct toxicity, but also considering the other indirect mechanisms. Because of the similarities between fine air particles and engineered nanomaterials, we compare the toxicities of engineered nanomaterials to those of fine air particles. Arthritis and joint injuries are prevalent, particularly in the elderly population. Considering the severity of global exposure to fine particles and limited studies assessing the detrimental effects of fine-particle exposure on joints and arthritis, this Review aims to appeal to a broad interest and to promote more research efforts in this field.

Seasonal variations in the oxidative stress and inflammatory potential of PM2.5 in Tehran using an alveolar macrophage model; The role of chemical composition and sources

The current study was designed to assess the association between temporal variations in urban PM_2.5 chemical composition, sources, and the oxidative stress and inflammatory response in an alveolar macrophage (AM) model. A year-long sampling campaign collected PM_2.5 samples at the Sharif University in Tehran, Iran. PM-induced reactive oxygen species (ROS) production was measured both with an acellular dithiothreitol consumption assay (DTT-ROS; ranged from 2.1 to 9.3 nmoles min^-1 m^-3) and an in vitro macrophage-mediated ROS production assay (AM-ROS; ranged from 125 to 1213 μg Zymosan equivalents m^-3). The production of tumor necrosis factor alpha (TNF-α; ranged from ~60 to 518 pg TNF-α m^-3) was quantified as a marker of the inflammatory potential of the PM. PM-induced DTT-ROS and AM-ROS were substantially higher for the colder months' PM (1.5-fold & 3-fold, respectively) compared with warm season. Vehicular emission tracers, aliphatic diacids, and hopanes exhibited moderate correlation with ROS measures. TNF-α secretion exhibited a markedly different pattern than ROS activity with a 2-fold increase in the warm months compared to the rest of the year. Gasoline vehicles and residual oil combustion were moderately associated with both ROS measures (R ≥ 0.67, p < 0.05), while diesel vehicles exhibited a strong correlation with secreted TNF-α in the cold season (R = 0.89, p < 0.05). mRNA expression of fourteen genes including antioxidant response and pro-inflammatory markers were found to be differentially modulated in our AM model. HMOX1, an antioxidant response gene, was up-regulated throughout the year. Pro-inflammatory genes (e.g. TNF-α and IL1β) were down-regulated in the cold season and displayed moderate to weak correlation with crustal elements (R > 0.5, p < 0.05). AM-ROS activity showed an inverse relationship with genes including SOD2, TNF, IL1β and IL6 (R ≥ -0.66, p < 0.01). Our findings indicate that Tehran's PM_2.5 has the potential to induce oxidative stress and inflammation responses in vitro. In the current study, these responses included NRF2, NF-κB and MAPK pathways.

Comprehensive hippocampal metabolite responses to PM2.5 in young mice

Fine particulate matter (PM_2.5) exposure alters brain development, clinical cognition and behavior in childhood. Previous studies of this subject have mainly been epidemiological investigations or analyses of gene and protein levels; however, gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling, which will help clarify the molecular mechanisms of susceptibility in PM_2.5-induced neurotoxicity, is lacking. In the present study, C57BL/6 mice at different ages (4 weeks, 4 months and 10 months) received oropharyngeal aspiration of PM_2.5 (3 mg/kg) every other day for 4 weeks. The Morris water maze showed that PM_2.5 exposure caused deterioration of spatial learning and memory in young (4 week old) mice. In addition, the levels of several metabolites belonging to different metabolite classes were significantly changed by PM_2.5 exposure in 4-week-old mice. Based on metabolic pathway analysis, we speculated that the decline in spatial learning and memory due to PM_2.5 exposure may be directly or indirectly associated with hippocampal region-specific metabolic alterations involving energy metabolism (citric acid, succinic acid, malic acid, maltose and creatinine); cholesterol metabolism (desmosterol, lanosterol and campesterol); arachidonic acid metabolism (methyl arachidonic acid, nonanoic acid and linoleic acid); inositol phosphate metabolism (myo-inositol, myo-inositol-1-phosphate and methyl-phosphate) and aspartic acid metabolism (aspartic acid, asparagine and homoserine).

Mortality and morbidity for cardiopulmonary diseases attributed to PM2.5 exposure in the metropolis of Rome, Italy

The aim of the study was to evaluate the health effects associated with the exposure to ground-level of particulate matters with aerodynamic diameter ≤ 2.5 μm (PM_2.5) on citizens in Rome (Italy) in 2015 and 2016. Based on the new version of the World Health Organization's AirQ+ model, we have estimated the short- and long-term effects of PM_2.5 on hospital admissions due to cardiovascular (HA-CVD) and respiratory diseases (HA-RD) as well as on mortality for ischemic heart disease (M-IHD) and chronic obstructive pulmonary disease (M-COPD). In this study, city-specific relative risk values and baseline incidence rates were used to calculate the association between PM_2.5 and daily counts of emergency hospitalizations and mortality. The annual mean PM_2.5 concentrations were 18 μg m^-3 and 14 μg m^-3 in 2015 and 2016, respectively. In Rome, the citizens are mostly exposed to daily mean PM_2.5 concentrations of 10-20 μg m^-3 during the study period. In 2015-2016, 0.4-0.6% for HA-CVD, 1.1-1.5% for HA-RD, 16.5-18.1% for M-IHD and 8.5-9.2% for M-COPD are attributed to PM_2.5. In 2015-2016, 134-186 HA-CVD, 126-175 HA-RD, 947-1037 M-IHD and 244-279 M-COPD, caused by PM_2.5 exposure, could be "avoided" if PM_2.5 concentrations would not exceed 10 μg m^-3, i.e. the threshold recommended by the World Health Organization. Thus, a consistent air quality management and sustainable city planning are needed, urgently, to mitigate the adverse effects of PM_2.5 exposure in Rome.

Acute effect of fine and coarse particular matter on cardiovascular visits in Ningbo, China

Although a growing number of epidemiological studies have been conducted on size-specific health effects of particulate matter in China, results remain inconsistent. In this study, we investigated acute effect of fine and coarse particular matter on cardiovascular hospital visits in Ningbo, China. We used generalized additive models to examine short-term effects of PM_2.5 and PM_10-2.5 on cardiovascular hospital visits by adjustment for temporal, seasonal, and meteorological effects. Subgroup analyses were conducted by age, sex, and season. We also examined the stability of their effects in multi-pollutant models. We found that PM_2.5 were associated with cardiovascular hospital visits (RR = 1.006; 95% CI 1.000, 1.011) and results remained similar after adjustment for PM_10-2.5 (RR = 1.005; 95% CI 0.998, 1.013). There was a borderline association between PM_10-2.5 and cardiovascular hospital visits (RR = 1.007; 95% CI 0.997, 1.016), which disappeared after controlling for PM_2.5 (RR = 1.000; 95% CI 0.988, 1.013). The associations appeared to be stronger in the cold season and among the elderly (≥ 75 years). The findings of this study suggested significant adverse effects of PM_2.5, but no independent effects of PM_10-2.5 on cardiovascular hospital visits. Additional studies are needed to confirm these findings.

Exogenous nanoparticles and endogenous crystalline molecules as danger signals for the NLRP3 inflammasomes

Inflammasome mechanisms are involved as some of the pathways of sterile inflammation. Inflammasomes are large multiprotein complexes in the cytosol and are a key system for the production of the pivotal inflammatory cytokines, interleukin (IL)-1β and IL-18, and inflammatory cell death called pyroptosis. Although a number of inflammasomes have been described, the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing 3 (NLRP3) is the most extensively investigated inflammasome. Exogenous pathogen-associated molecular patterns released during infection and endogenous crystalline danger/damage-associated molecular patterns (DAMPs) are well-known activators of NLRP3 inflammasomes. In addition, nanoparticle-associated molecular patterns (NAMPs), which are mediated by synthetic materials, including nanomaterials and nanoparticles, are proposed to be new danger signals of NLRP3 inflammasomes. Importantly, NAMP- and DAMP-triggered inflammation, a defining characteristic in inflammatory diseases, is termed as sterile inflammation because it occurs in the absence of foreign pathogens. This review focuses on the role of inflammasomes in exogenous NAMP- and endogenous crystalline DAMP-mediated sterile inflammation. Moreover, many regulatory mechanisms have been identified to attenuate NLRP3 inflammasomes. Therefore, we also summarize endogenous negative regulators of NLRP3 inflammasome activation, particularly induced by NAMPs or crystalline DAMPs.

Anti-inflammatory potential of alginic acid from Sargassum horneri against urban aerosol-induced inflammatory responses in keratinocytes and macrophages

The airborne particulate pollutants originating in the deserts of Mongolia and China which becomes contaminated with industrial effluents and traffic emissions while moving with the wind currents towards East Asia has recently become a serious environmental and health issue in the region. They cause asthma, collateral lung tissue damage, oxidative stress, allergic reactions, and inflammation. The current study was undertaken to evaluate the protective effects of alginate extracted from the invasive alga Sargassum horneri (SHA) against fine dust collected from Beijing, China (Chinese fine dust; CFD). It was found that CFD induces inflammation in HaCaT keratinocytes and inhibits macrophage activation. All of the particulate matter (PM) comprising CFD was < PM13 majority being < PM2.5 which is defined for mineral elements and polycyclic aromatic hydrocarbons. SHA attenuated PGE2 levels in CFD-induced HaCaT keratinocytes. The IC50 for SHA was 36.63 ± 4.11 µg mL-l. SHA also reduced the levels of COX-2, IL-6, and TNF-α, and inhibited certain key molecular mediators of the NF-κB and MAPK pathways in keratinocytes. SHA substantially reduced the levels of CFD-derived metal ions like Pb2+ and Ca2+ in keratinocytes attributable to its metal ion chelating properties. CFD-induced HaCaT keratinocyte culture media increased inflammatory responses in RAW 264.7 macrophages. These cells presented with increased levels of NO, iNOS, COX-2, PGE2, and pro-inflammatory cytokines. It was found that the aforementioned effects could be reversed in RAW 264.7 macrophages when keratinocytes were treated with SHA. Therefore, SHA could be used against fine dust-induced inflammation in keratinocytes.

Sources of Airborne Endotoxins in Ambient Air and Exposure of Nearby Communities—A Review

Endotoxin is a bioaerosol component that is known to cause respiratory effects in exposed populations. To date, most research focused on occupational exposure, whilst much less is known about the impact of emissions from industrial operations on downwind endotoxin concentrations. A review of the literature was undertaken, identifying studies that reported endotoxin concentrations in both ambient environments and around sources with high endotoxin emissions. Ambient endotoxin concentrations in both rural and urban areas are generally below 10 endotoxin units (EU) m−3; however, around significant sources such as compost facilities, farms, and wastewater treatment plants, endotoxin concentrations regularly exceeded 100 EU m−3. However, this is affected by a range of factors including sampling approach, equipment, and duration. Reported downwind measurements of endotoxin demonstrate that endotoxin concentrations can remain above upwind concentrations. The evaluation of reported data is complicated due to a wide range of different parameters including sampling approaches, temperature, and site activity, demonstrating the need for a standardised methodology and improved guidance. Thorough characterisation of ambient endotoxin levels and modelling of endotoxin from pollution sources is needed to help inform future policy and support a robust health-based risk assessment process.

Sargassum horneri (Turner) C. Agardh ethanol extract inhibits the fine dust inflammation response via activating Nrf2/HO-1 signaling in RAW 264.7 cells

BACKGROUND

Among the different kinds of pollution, air pollution continues to increase globally. East Asia is considered to be significantly affected. As a result, the populations in these regions face serious health issues including respiratory disorders. This study investigated the impact of fine dust (FD) particles (CRM No. 28) on macrophage cells as a model for alveolar lung cells.

METHODS

The research focused on inflammation and oxidative stress induced by FD and Sargassum horneri (Turner) C. Agardh ethanol extract (SHE) as a potential treatment. S. horneri is a type of brown algae that has demonstrated anti-inflammatory effects against RAW 264.7 macrophages in previous studies. MTT, Griess, ELISA, western blotting, and mRNA expression analyses using PCR techniques were used in this study.

RESULTS

The optimum FD concentration was determined to be 125 μg mL- 1. FD particles stimulated inflammatory mediators production (iNOS, COX-2, and PGE2) and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), leading to NO production. These mediators were dose-dependently downregulated by treatment with SHE. IL-6 and TNF-α were identified as biomarkers for FD. SHE treatment induced HO-1 and Nrf2 activity in a dose-dependent manner under FD stimulation. This confirmed the cytoprotective effect against oxidative stress induced via FD. Furthermore, treatment of the cells with a p38 MAPK inhibitor (SB202190) induced FD-stimulated NO production.

CONCLUSIONS

The results suggest that SHE increases macrophage cellular resistance to FD-induced inflammation and oxidative stress, probably via the p38 MAPK pathway and Nrf2/HO-1 expression.

Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation

Objective

Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge.

Methods

We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM∆C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM.

Results

Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM∆C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge.

Conclusions

Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

Macrophage Recognition of Crystals and Nanoparticles

Inhalation of exogenous crystals such as silica, asbestos, and carbon nanotubes can cause lung fibrosis and cancer. Endogenous crystals such as monosodium urate, cholesterol, and hydroxyapatite are associated with pathogenesis of gout, atherosclerosis, and osteoarthritis, respectively. These crystal-associated-inflammatory diseases are triggered by the macrophage NLRP3 inflammasome activation and cell death. Therefore, it is important to understand how macrophages recognize crystals. However, it is unlikely that macrophages have evolutionally acquired receptors specific for crystals or recently emerged nanoparticles. Several recent studies have reported that some crystal particles are negatively charged and are recognized by scavenger receptor family members in a charge-dependent manner. Alternatively, a model for receptor-independent phagocytosis of crystals has also been proposed. This review focuses on the mechanisms by which macrophages recognize crystals and nanoparticles.