Oxidative stress and apoptosis are induced in human endothelial cells exposed to urban particulate matter

The Oxidative Potential of Airborne Particulate Matter Research Trends, Challenges, and Future Perspectives-Insights from a Bibliometric Analysis and Scoping Review

This study is a comprehensive analysis of the oxidative potential (OP) of particulate matter (PM) and its environmental and health impacts. The researchers conducted a bibliometric analysis and scoping review, screening 569 articles and selecting 368 for further analysis. The study found that OP is an emerging field of study, with a notable increase in the number of publications in the 2010s compared to the early 2000s. The research is primarily published in eight journals and is concentrated in a few academic and university-based institutions. The study identified key research hotspots for OP-PM, emphasizing the importance of capacity building, interdisciplinary collaboration, understanding emission sources and atmospheric processes, and the impacts of PM and its OP. The study highlighted the need to consider the effects of climate change on OP-PM and the regulatory framework for PM research. The findings of this study will contribute to a better understanding of PM and its consequences, including human exposure and its effects. It will also inform strategies for managing air quality and protecting public health. Overall, this study provides valuable insights into the field of OP-PM research and highlights the need for continued research and collaboration to address the environmental and health impacts of PM.

Inflammatory response in mouse lungs to haze episodes under different backgrounds of particulate matter exposure

Particulate matter (PM) toxicity has mostly been investigated through in vitro exposure or tracheal infusion in animal models. However, given the complexity of ambient conditions, most animal studies do not mimic real-life PM exposure. In this work, we established a novel integrated exposure model to study the dynamic inflammatory response and defense strategies in ambient PM-exposed mice. Three groups of male C57BL/6 mice were kept in three chambers with pre-exposure to filtered air (FA), unfiltered air (UFA), or the air with a low PM concentration (PM2.5 ≤ 75 μg/m3) (LPM), respectively, for 37 days. Then all three groups of mice were exposed to haze challenge for 3 days, followed by exposure in filtered air for 7 days to allow recovery. Our results suggest that following a haze challenge, the defense strategies of mice of filtered air (FA) and low PM (LPM) groups comprised a form of "counterattack", whereas the response of the unfiltered air (UFA) group could be viewed as a "silence". While the latter strategy protected the lung tissues of mice from acute inflammatory damage, it also foreshadowed the development of chronic inflammatory diseases. These findings contribute to explaining previously documented PM-associated pathogenic mechanisms.

The impact of particulate matters on apoptosis in various organs: Mechanistic and therapeutic perspectives

Ecological air contamination is the non-homogenous suspension of insoluble particles into gas or/and liquid fluids known as particulate matter (PM). It has been discovered that exposure to PM can cause serious cellular defects, followed by tissue damage known as cellular stress. Apoptosis is a homeostatic and regulated phenomenon associated with distinguished physiological actions inclusive of organ and tissue generation, aging, and development. Moreover, it has been proposed that the deregulation of apoptotic performs an active role in the occurrence of many disorders, such as autoimmune disease, neurodegenerative, and malignant, in the human population. Recent studies have shown that PMs mainly modulate multiple signaling pathways involved in apoptosis, including MAPK, PI3K/Akt, JAK/STAT, NFκB, Endoplasmic Stress, and ATM/P53, leading to apoptosis dysregulation and apoptosis-related pathological conditions. Here, the recently published data concerning the effect of PM on the apoptosis of various organs, with a particular focus on the importance of apoptosis as a component in PM-induced toxicity and human disease development, is carefully discussed. Moreover, the review also highlighted the various therapeutic approaches, including small molecules, miRNA replacement therapy, vitamins, and PDRN, for treating diseases caused by PM toxicity. Notably, researchers have considered medicinal herbs a potential treatment for PM-induced toxicity due to their fewer side effects. So, in the final section, we analyzed the performance of some natural products for inhibition and intervention of apoptosis arising from PM-induced toxicity.

Impact of air pollution on cardiovascular aging

The world population is aging rapidly, and by some estimates, the number of people older than 60 will double in the next 30 years. With the increase in life expectancy, adverse effects of environmental exposures start playing a more prominent role in human health. Air pollution is now widely considered the most detrimental of all environmental risk factors, with some studies estimating that almost 20% of all deaths globally could be attributed to poor air quality. Cardiovascular diseases are the leading cause of death worldwide and will continue to account for the most significant percentage of non-communicable disease burden. Cardiovascular aging with defined pathomechanisms is a major trigger of cardiovascular disease in old age. Effects of environmental risk factors on cardiovascular aging should be considered in order to increase the health span and reduce the burden of cardiovascular disease in older populations. In this review, we explore the effects of air pollution on cardiovascular aging, from the molecular mechanisms to cardiovascular manifestations of aging and, finally, the age-related cardiovascular outcomes. We also explore the distinction between the effects of air pollution on healthy aging and disease progression. Future efforts should focus on extending the health span rather than the lifespan.

Effects of urban particulate matter on the quality of erythrocytes

With the acceleration of industrialisation and urbanisation, air pollution has become a serious global concern as a hazard to human health, with urban particulate matter (UPM) accounting for the largest share. UPM can rapidly pass into and persist within systemic circulation. However, few studies exist on whether UPM may have any impact on blood components. In this study, UPM standards (SRM1648a) were used to assess the influence of UPM on erythrocyte quality in terms of oxidative and metabolic damage as well as phagocytosis by macrophages in vitro and clearance in vivo. Our results showed that UPM had weak haemolytic properties. It can oxidise haemoglobin and influence the oxygen-carrying function, redox balance, and metabolism of erythrocytes. UPM increases the content of reactive oxygen species (ROS) and decreases antioxidant function according to the data of malonaldehyde (MDA), glutathione (GSH), and glucose 6 phosphate dehydrogenase (G6PDH). UPM can adhere to or be internalised by erythrocytes at higher concentrations, which can alter their morphology. Superoxide radicals produced in the co-incubation system further disrupted the structure of red blood cell membranes, thereby lowering the resistance to the hypotonic solution, as reflected by the osmotic fragility test. Moreover, UPM leads to an increase in phosphatidylserine exposure in erythrocytes and subsequent clearance by the mononuclear phagocytic system in vivo. Altogether, this study suggests that the primary function of erythrocytes may be affected by UPM, providing a warning for erythrocyte quality in severely polluted areas. For critically ill patients, transfusion of erythrocytes with lesions in morphology and function will have serious clinical consequences, suggesting that potential risks should be considered during blood donation screening. The current work expands the scope of blood safety studies.

Diesel exhaust particles induce human umbilical vein endothelial cells apoptosis by accumulation of autophagosomes and caspase-8 activation

Diesel exhaust particles (DEP) are risk factors for endothelial cells (ECs) dysfunction. However, the mechanism by which DEP induce ECs apoptosis remains unclear. Here, we investigated how DEP induce death of human umbilical vein ECs (HUVECs), with a focus on the autophagy-mediated apoptotic pathway. DEP induced dose-dependent HUVECs death and exposure to the IC₅₀ concentration of DEP (70 µg/ml) led to apoptosis. DEP phosphorylated Beclin-1 (Ser93) and increased protein levels of p62 and LC3BII and the number of LC3B puncta, indicating autophagy initiation. DEP increased expression of pro- and mature forms of cathepsin D, which increases lysosomal activity. However, DEP suppressed expression of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor proteins (STX17, VAMP8, SNAP29, YKT6, and STX7) to inhibit autolysosome formation, resulting in accumulation of autophagosomes. LC3B, p62, and caspase-8 form a tertiary complex in accumulated autophagosomes, which is known to serve as a platform for caspase-8 activation. Indeed, DEP activates caspase-8 and pretreatment with a caspase-8 inhibitor suppressed DEP-induced apoptosis. Furthermore, depletion of p62 decreased caspase-8 and caspase-3 activation and inhibited the DEP-induced apoptosis. Taken together, these findings demonstrated that DEP induced HUVECs apoptosis by inhibiting autophagosome maturation and identified caspase-8 as a novel mediator of DEP-induced ECs apoptosis.

Global research trends in atherosclerosis: A bibliometric and visualized study

Background

Increasing evidence has spurred a considerable evolution of concepts related to atherosclerosis, prompting the need to provide a comprehensive view of the growing literature. By retrieving publications in the Web of Science Core Collection (WoSCC) of Clarivate Analytics, we conducted a bibliometric analysis of the scientific literature on atherosclerosis to describe the research landscape.

Methods

A search was conducted of the WoSCC for articles and reviews serving exclusively as a source of information on atherosclerosis published between 2012 and 2022. Microsoft Excel 2019 was used to chart the annual productivity of research relevant to atherosclerosis. Through CiteSpace and VOSviewer, the most prolific countries or regions, authors, journals, and resource-, intellectual-, and knowledge-sharing in atherosclerosis research, as well as co-citation analysis of references and keywords, were analyzed.

Results

A total of 20,014 publications were retrieved. In terms of publications, the United States remains the most productive country (6,390, 31,93%). The most publications have been contributed by Johns Hopkins Univ (730, 3.65%). ALVARO ALONSO produced the most published works (171, 0.85%). With a betweenness centrality of 0.17, ERIN D MICHOS was the most influential author. The most prolific journal was identified as Atherosclerosis (893, 4.46%). Circulation received the most co-citations (14,939, 2.79%). Keywords with the ongoing strong citation bursts were “nucleotide-binding oligomerization (NOD), Leucine-rich repeat (LRR)-containing protein (NLRP3) inflammasome,” “short-chain fatty acids (SCFAs),” “exosome,” and “homeostasis,” etc.

Conclusion

The research on atherosclerosis is driven mostly by North America and Europe. Intensive research has focused on the link between inflammation and atherosclerosis, as well as its complications. Specifically, the NLRP3 inflammasome, interleukin-1β, gut microbiota and SCFAs, exosome, long non-coding RNAs, autophagy, and cellular senescence were described to be hot issues in the field.

The Impact of Fine Particulate Matter 2.5 on the Cardiovascular System: A Review of the Invisible Killer

Air pollution exerts several deleterious effects on the cardiovascular system, with cardiovascular disease (CVD) accounting for 80% of all premature deaths caused by air pollution. Short-term exposure to particulate matter 2.5 (PM_2.5) leads to acute CVD-associated deaths and nonfatal events, whereas long-term exposure increases CVD-associated risk of death and reduces longevity. Here, we summarize published data illustrating how PM_2.5 may impact the cardiovascular system to provide information on the mechanisms by which it may contribute to CVDs. We provide an overview of PM_2.5, its associated health risks, global statistics, mechanistic underpinnings related to mitochondria, and hazardous biological effects. We elaborate on the association between PM_2.5 exposure and CVD development and examine preventive PM_2.5 exposure measures and future strategies for combating PM_2.5-related adverse health effects. The insights gained can provide critical guidelines for preventing pollution-related CVDs through governmental, societal, and personal measures, thereby benefitting humanity and slowing climate change.

The involvement of DRP1-mediated caspase-1 activation in inflammatory response by urban particulate matter in EA.hy926 human vascular endothelial cells

Atmospheric particulate matter (PM) has been reported to be closely related to cardiovascular adverse events. However, the underlying mode of action remains to be elucidated. Previous studies have documented that PM induces mitochondrial damage and inflammation, the relation between these two biological outcomes is still unclear though. In this study, we used EA.hy926 human vascular endothelial cells and a standard PM, PM SRM1648a to study the potential effects of mitochondrial dysfunction on endothelial inflammatory responses. As a result, PM SRM1648a changes mitochondrial morphology and interrupts mitochondrial dynamics with a persistent tendency of fission in a dose-dependent manner. Additionally, the caspase-1/IL-1β axis is involved in inflammatory responses but not cell pyroptosis in EA.hy926 cells following the exposure to PM SRM1648a. The activation of caspase-1 has implications in inflammation but not pyroptosis, because caspase-1-dependent pyroptosis is not the main modality of cell death in PM SRM1648a-treated EA.hy926 cells. With regard to the association between mitochondrial damage and inflammation in the case of particle stimulation, DRP1-mediated mitochondrial fission is responsible for inflammatory responses as a result of caspase-1 activation. The current study showed that PM SRM1648a has the ability to disturb mitochondrial dynamics, and trigger endothelial inflammation via DRP1/caspase-1/IL-1β regulatory pathway. In a conclusion, mitochondrial fission enables EA.hy926 cells to facilitate caspase-1 activation in response to PM SRM1648a, which is a crucial step for inflammatory reaction in vascular endothelial cells.

The critical role of epigenetic mechanism in PM2.5-induced cardiovascular diseases

Cardiovascular disease (CVD) has become the leading cause of death worldwide, which seriously threatens human life and health. Epidemiological studies have confirmed the occurrence and development of CVD are closely related to air pollution. In particular, fine particulate matter (PM_2.5) is recognized as an important environmental factor contributing to increased morbidity, mortality and hospitalization rates among adults and children. However, the underlying mechanism by which PM_2.5 promotes CVD development remains unclear. With the development of epigenetics, recent studies have shown that PM_2.5 exposure may induce or aggravate CVD through epigenetic changes. In order to better understand the potential mechanisms, this paper reviews the epigenetic changes of CVD caused by PM_2.5. We summarized the epigenetic mechanisms of PM_2.5 causing cardiovascular pathological damage and functional changes, mainly involving DNA methylation, non-coding RNA, histone modification and chromosome remodeling. It will provide important clues for exploring the biological mechanisms affecting cardiovascular health.

Metabolic Response of RAW 264.7 Macrophages to Exposure to Crude Particulate Matter and a Reduced Content of Organic Matter

Exposure to air pollution from various airborne particulate matter (PM) is regarded as a potential health risk. Airborne PM penetrates the lungs, where it is taken up by macrophages, what results in macrophage activation and can potentially lead to negative consequences for the organism. In the present study, we assessed the effects of direct exposure of RAW 264.7 macrophages to crude PM (NIST1648a) and to a reduced content of organic matter (LAp120) for up to 72 h on selected parameters of metabolic activity. These included cell viability and apoptosis, metabolic activity and cell number, ROS synthesis, nitric oxide (NO) release, and oxidative burst. The results indicated that both NIST1648a and LAp120 negatively influenced the parameters of cell viability and metabolic activity due to increased ROS synthesis. The negative effect of PM was concentration-dependent; i.e., it was the most pronounced for the highest concentration applied. The impact of PM also depended on the time of exposure, so at respective time points, PM induced different effects. There were also differences in the impact of NIST1648a and LAp120 on almost all parameters tested. The negative effect of LAp120 was more pronounced, what appeared to be associated with an increased content of metals.

The In Vitro Proinflammatory Properties of Water Accommodated Sediment Extracts from a Creosote-Contaminated US Environmental Protection Agency Superfund Site

The southern branch of the Elizabeth River near Portsmouth, Virginia, USA, is one of the most creosote-polluted subestuaries in North America and the former location of the Atlantic Wood US Environmental Protection Agency Superfund site. We previously demonstrated that adult Atlantic Wood killifish collected in situ had severe hepatic lesions, including hepatoblastoma and hepatocellular carcinoma, as well as suppressed circulating antibody responses compared to a historical reference site. Moreover, several innate immune functions were higher in Atlantic Wood fish, including elevated expression of hepatic cyclooxygenase-2 (COX-2), suggesting a proinflammatory environment. To further examine the potential of Atlantic Wood contaminants to modulate innate immune function(s), the present study used RAW264.7 mouse macrophages as an in vitro model to develop new approach methodologies for rapid screening. Lipopolysaccharide (LPS)-stimulated nitric oxide secretion by macrophages is a rapid, sensitive, and predictive in vitro system for screening potentially immunotoxic contaminants as single compounds or as complex mixtures. Compared to the reference site, filter-sterilized Atlantic Wood sediment extracts (water accommodated fractions) induced nitric oxide and IL-6 secretion as well as inducible nitric oxide synthase and COX-2 proteins at levels comparable to or higher than those induced by LPS treatments alone. Extracts also increased phagocytic activity by macrophages. Using a limulus lysate assay, we show that bacterial endotoxin levels in Atlantic Wood extracts are higher than in reference extracts and that polymyxin-B chelation ameliorates proinflammatory effects. These findings illuminate the reality of sediment constituents other than toxic compounds previously associated with developmental abnormalities and carcinogenesis in killifish from the Atlantic Wood site. Perhaps these data also suggest the presence of contaminant-adapted consortia of sediment microbes at many heavily polluted sites worldwide compared to less contaminated sites. Environ Toxicol Chem 2021;40:1576-1585. © 2021 SETAC.

Acute kidney damage by PM2.5 exposure in a rat model

PM2.5 exposure is associated with a glomerular filtration rate (GFR) reduction, and renal tissue damage. The goal of this study was demonstrate the acute effect of PM2.5 on the kidney. Male rats were acutely exposed to PM2.5 or filtered air. Blood pressure was mesure and early kidney biomarkers were evaluated in serum and urine samples, and also IL-1β, IL-6 and TNFα were determined. Oxidative biomarkers, angiotensin/bradykinin-related proteins, KIM-1, IL-6 and histology were determined. Blood pressure, GFR, and early kidney damage biomarkers increase together with oxidative biomarkers and angiotensin/bradykinin endocrine-related proteins increased after exposure to PM2.5. Urinary IL-6 increased after exposure to PM2.5, whereas in kidney cortex decreased. Histological changes were observed and accompanied by the induction of KIM-1. Acute exposure to PM2.5 not decline kidney function. However, it can induce early kidney damage biomarkers, oxidative stress, inflammation and angiotensin mediators, which perhabs culminates in a lose of renal function.

The critical role of endothelial function in fine particulate matter-induced atherosclerosis

Ambient and indoor air pollution contributes annually to approximately seven million premature deaths. Air pollution is a complex mixture of gaseous and particulate materials. In particular, fine particulate matter (PM2.5) plays a major mortality risk factor particularly on cardiovascular diseases through mechanisms of atherosclerosis, thrombosis and inflammation. A review on the PM2.5-induced atherosclerosis is needed to better understand the involved mechanisms. In this review, we summarized epidemiology and animal studies of PM2.5-induced atherosclerosis. Vascular endothelial injury is a critical early predictor of atherosclerosis. The evidence of mechanisms of PM2.5-induced atherosclerosis supports effects on vascular function. Thus, we summarized the main mechanisms of PM2.5-triggered vascular endothelial injury, which mainly involved three aspects, including vascular endothelial permeability, vasomotor function and vascular reparative capacity. Then we reviewed the relationship between PM2.5-induced endothelial injury and atherosclerosis. PM2.5-induced endothelial injury associated with inflammation, pro-coagulation and lipid deposition. Although the evidence of PM2.5-induced atherosclerosis is undergoing continual refinement, the mechanisms of PM2.5-triggered atherosclerosis are still limited, especially indoor PM2.5. Subsequent efforts of researchers are needed to improve the understanding of PM2.5 and atherosclerosis. Preventing or avoiding PM2.5-induced endothelial damage may greatly reduce the occurrence and development of atherosclerosis.

Acute exposure to traffic-related air pollution alters antioxidant status in healthy adults

BACKGROUND

Exposure to traffic-related air pollution is associated with an increased risk of cardiovascular and respiratory disease. Evidence suggests that inhaled pollutants precipitate these effects via multiple pathways involving oxidative stress.

OBJECTIVE

Postulating that a decrease in circulating antioxidant levels reflect an oxidative response, we investigated the effect of inhaled diesel exhaust (DE) on the ratio of reduced to oxidized glutathione (GSH/GSSG) in healthy adults, and whether pre-exposure antioxidant supplementation blunted this response. We also examined exposure-related changes in antioxidant/stress response leukocyte gene expression (GCLc, HMOX-1, IL-6, TGFβ) and plasma IL-6 levels.

METHODS

Nineteen nonsmoking adults participated in a double-blind, randomized, four-way crossover study. Each subject completed 120-min exposures to filtered air and DE (200 μg/m3), with and without antioxidant pretreatment. Antioxidant comprised 1000 mg ascorbate for 7 days and 1200 mg N-acetylcysteine 1 day prior to exposure, with 1000 mg and 600 mg, respectively, administered 2 h prior to exposure. Whole blood glutathione was measured pre- and post-exposure; plasma IL-6 and mRNA expression were quantified pre, during and post exposure.

RESULTS

Diesel exhaust exposure was associated with significantly decreased GSH/GSSG (p = 0.001) and a 4-fold increase in IL-6 mRNA (p = 0.01) post exposure. Antioxidant pretreatment did not significantly mediate the effect of DE exposure on GSH/GSSG, though appeared to decrease the effect of exposure on IL-6 mRNA expression.

CONCLUSIONS

Acute DE inhalation induced detectable oxidative effects in healthy adults, which were not significantly attenuated by the selected antioxidant pre-treatment. This finding supports the premise that oxidative stress is one mechanism underlying the adverse effects of traffic-related air pollution.

Effects of antioxidants on oxidative stress and inflammatory responses of human bronchial epithelial cells exposed to particulate matter and cigarette smoke extract

Particulate matter (PM) is a type of air pollutant that induces adverse health effects, including acute exacerbation of chronic obstructive pulmonary disease (COPD). However, the effects of co-exposure to PM and cigarette smoke extract (CSE) on bronchial epithelial cells remain unknown. This study investigated the cytotoxic and pro-inflammatory effects of combined exposure to PM and CSE on bronchial epithelial cells, and assessed the potential of antioxidants to inhibit CSE/PM-induced oxidative stress and inflammation. Exposure of epithelial cells to PM or CSE induced cytotoxicity, inflammation, and oxidative stress, all of which were dramatically increased when cells were exposed to the combination of CSE and PM. Importantly, the adverse effects of CSE/PM exposure were suppressed when cells were treated with sulforaphane (SFN) or sulforaphane N-acetylcysteine (SFNAC). Furthermore, SFN and SFNAC suppressed the CSE/PM-induced pro-inflammatory cytokine production and expression of inflammatory genes. Combined PM and CSE exposure further activated the MAPK and Nrf2 signaling pathways. SFN and SFNAC attenuated CSE/PM-induced epithelial toxicity through the ERK/JNK signaling pathway-dependent inhibition of inflammation. Moreover, SFN and SFNAC suppressed ROS generation by activating antioxidant enzymes and Nrf2 signaling. Therefore, SFN and SFNAC could be a promising approach to prevent or mitigate the exacerbation of pulmonary diseases caused by PM and other air pollutants.

Urban PM2.5 Induces Cellular Toxicity, Hormone Dysregulation, Oxidative Damage, Inflammation, and Mitochondrial Interference in the HRT8 Trophoblast Cell Line

Objective: Epidemiological studies have found air pollution to be a driver of adverse pregnancy outcomes, including gestational diabetes, low term birth weight and preeclampsia. It is unknown what biological mechanisms are involved in this process. A first trimester trophoblast cell line (HTR-8/SVneo) was exposed to various concentrations of PM2.5 (PM2.5) in order to elucidate the effect of urban particulate matter (PM) of size <2.5 μm on placental function. Methods: PM2.5 were collected at a site representative of urban traffic and dispersed in cell media by indirect and direct sonication. The HTR-8 cells were grown under standard conditions. Cellular uptake was studied after 24 and 48 h of exposure by transmission electron microscopy (TEM). The secretion of human chorionic gonadotropin (hCG), progesterone, and Interleukin-6 (IL-6) was measured by ELISA. Changes in membrane integrity and H₂O₂ production were analyzed using the CellTox^TM Green Cytotoxicity and ROSGlo^TM assays. Protease activity was evaluated by MitoTox^TM assay. Mitochondrial function was assessed through high resolution respirometry in an Oroboros O2k-FluoRespirometer, and mitochondrial content was quantified by citrate synthase activity. Results: TEM analysis depicted PM2.5 cellular uptake and localization of the PM2.5 to the mitochondria after 24 h. The cells showed aggregated cytoskeleton and generalized necrotic appearance, such as chromatin condensation, organelle swelling and signs of lost membrane integrity. The mitochondria displayed vacuolization and disruption of cristae morphology. At 48 h exposure, a significant drop in hCG secretion and a significant increase in progesterone secretion and IL-6 production occurred. At 48 h exposure, a five-fold increase in protease activity and a significant alteration of H₂O₂ production was observed. The HTR-8 cells exhibited evidence of increased cytotoxicity with increasing exposure time and dose of PM2.5. No significant difference in mitochondrial respiration or mitochondrial mass could be demonstrated. Conclusion: Following exposure to air pollution, intracellular accumulation of PM may contribute to the placental dysfunction associated with pregnancy outcomes, such as preeclampsia and intrauterine growth restriction, through their direct and indirect effects on trophoblast protein secretion, hormone regulation, inflammatory response, and mitochondrial interference.

Deciphering the Code between Air Pollution and Disease: The Effect of Particulate Matter on Cancer Hallmarks

Air pollution has been recognized as a global health problem, causing around 7 million deaths worldwide and representing one of the highest environmental crises that we are now facing. Close to 30% of new lung cancer cases are associated with air pollution, and the impact is more evident in major cities. In this review, we summarize and discuss the evidence regarding the effect of particulate matter (PM) and its impact in carcinogenesis, considering the “hallmarks of cancer” described by Hanahan and Weinberg in 2000 and 2011 as a guide to describing the findings that support the impact of particulate matter during the cancer continuum.

Particulate matters induce acute exacerbation of allergic airway inflammation via the TLR2/NF-κB/NLRP3 signaling pathway

BACKGROUND

Exposure to particulate matters (PMs) can lead to an acute exacerbation of allergic airway diseases, increasing the severity of symptoms and mortality. However, little is known about the underlying molecular mechanism. This study aimed to investigate the effects of PMs on acute exacerbation of allergic airway inflammation and seek potential therapeutic targets.

METHODS

Non-allergic control and ovalbumin (OVA)-allergic wide-type (WT) and Toll-like receptor 2 knockout (Tlr2-/-) mice were exposed to 100 μg of PM (diameter 5.85 μm) or saline by the oropharyngeal instillation. The responses were examined three days after exposure. In the RAW264.7 macrophage cell line, Tlr2 was knocked down by small-interfering RNA or the NF-κB inhibitor JSH-23 was used, and then the cells were stimulated with PMs for 12 h before comparison of the inflammatory responses.

RESULTS

PM exposure led to increased inflammatory cell recruitment and airway intensity of PAS + staining in OVA-allergic WT mice, accompanied with an accumulation of inflammatory cells and elevated inflammatory cytokines, such as IL-6 and IL-18, in the bronchoalveolar lavage fluid (BALF). Furthermore, the protein levels of TLR2 and the NLRP3 inflammasome were elevated concomitantly with the airway inflammation post-OVA/PMs challenge. Tlr2 deficiency effectively inhibited the airway inflammation, including pulmonary inflammatory cell recruitment, mucus secretion, serum OVA-specific immunoglobulin E (IgE), and BALF inflammatory cytokine production. Additionally, the P-induced NLRP3 activation in the RAW 264.7 cell line was diminished by the knockdown of Tlr2 or JSH-23 treatment in vitro.

CONCLUSION

Our results indicated that PMs exacerbate the allergic airway inflammation mediated by the TLR2/ NF-κB/NLRP3 signaling pathway. Inhibition of NF-κB seems to be a possible treatment.

Ambient fine particulate matter induces inflammatory responses of vascular endothelial cells through activating TLR-mediated pathway

This study aims to investigate the role of Toll-like receptors (TLRs) on fine particulate matter (PM_2.5)-induced inflammatory responses of vascular endothelial cells. Inflammatory factors and TLRs were examined in the aorta of mice after nonsurgical intratracheal instillation of PM_2.5 as well as in the human umbilical vein endothelial cells (HUVECs) treated with PM_2.5. In addition, the effects of TLR2 and TLR4 inhibitors in the secretion of interleukin 6 (IL-6) and IL-1β and the expression of TLRs were determined in the HUVECs. The results showed that PM_2.5 could increase the expression of IL-1β, IL-6, TLR2, and TLR4 in vitro and in vivo. Anti-TLR2 IgG or TAK242, an inhibitor of TLR4, decreased the secretion of IL-1β and IL-6 by HUVECs and reduced the expression of corresponding TLRs. In conclusion, we demonstrate that both TLR2 and TLR4 are involved in PM_2.5-induced inflammatory responses of vascular endothelial cells. Inhibition of TLR2 and TLR4 expression has the potential to prevent PM_2.5-induced cardiovascular diseases.

Rooibos (Aspalathus linearis) and honeybush (Cyclopia species) modulate the oxidative stress associated injury of diesel exhaust particles in human umbilical vein endothelial cells

BACKGROUND

Previous evidence show foods and beverages rich in polyphenolic compounds to have favourable effects on the cardiovascular system.

HYPOTHESIS

The current study assessed the modulation of oxidative stress and associated inflammation induced by diesel exhaust particles (DEP - SRM 2975) by pre-treatment of human umbilical vein endothelial cells (HUVECs) with aqueous extracts of rooibos [fermented (FR) as well as green form (GR)] and honeybush [fermented form (FH)].

STUDY DESIGN

HUVEC are either exposed to DEP (10 µg/ml) for 4 h or pre-treated with 40 and 60 µg/ml of FR or GH or FR, or 50 µg/ml orientin (OR) for 6 h prior to DEP exposure.

METHODS

In vitro antioxidant capacity of the extracts was assessed and the polyphenol contents were also assessed by HPLC. ROS, cell viability, lactate dehydrogenase leakage, lipid peroxidation, GSH:GSSG ratios, conjugated diene and protein carbonyl levels were determined as indices of oxidative stress and cytotoxicity. RT-qPCR and western blot were used to assess inflammatory cytokines and antioxidant genes expression.

RESULTS

DEP caused a dose and time-dependent increase in ROS production, significant (p < 0.001) increase in protein carbonyl (PC) formation, thiobarbituric acid reactive substances and conjugated dienes levels (p < 0.01) and a significant reduction in glutathione (GSH) redox status. Pre-incubation with either the herbal extracts or orientin attenuated these effects. The significant increase in IL-1α, IL-6, IL-8, VCAM-1 and ATF4 gene expression caused by DEP (10 µg/ml) were also attenuated by the presence of the FR, GR and FH extracts, and OR . Pre-treatment with the rooibos extracts or flavone orientin enhanced cell viability, reduced LDH leakage, enhanced mRNA expression of NQO1 and Nrf2, but repressed CYP1B1 mRNA induced by DEP. Western blot showed both the herbal tea extracts and orientin to enhance NQO1 and γGSC protein induction by DEP.

CONCLUSION

Taken together, the herbal extracts offer protection against DEP-induced oxidative stress and inflammatory response.

The cardiovascular protective effects of rooibos (Aspalathus linearis) extract on diesel exhaust particles induced inflammation and oxidative stress involve NF-κB- and Nrf2-dependent pathways modulation

Studies have shown that diesel exhaust particles (DEP) induced oxidative stress and inflammation. This present study examined the molecular effects of aqueous rooibos extract (RE) on the cardiovascular toxic effect of methanol extract of DEP in exposed Wistar rats. The results showed that DEP caused significant (p < 0.001) increase in MDA and CDs levels in the aorta and heart but this increase was significantly (p < 0.001) attenuated by rooibos extract. DEP induced IL-8, TNFα, IL-1β and decreased IL-10 gene expressions, all of which were reversed in the presence of rooibos extract. The expression of NF-κB, and IκKB genes were also significantly (p < 0.001) induced by DEP in both tissues, but pre-treatment with RE attenuated these effects. In contrast, DEP repressed IκB mRNA level, which was significantly (p < 0.001) reversed by rooibos extract pre-treatment. In addition, pre-treatment with rooibos extract attenuated the increased Nrf2 and HO-1 mRNA levels caused by DEP. This indicates the potential of rooibos extract to protect against DEP-induced cardiovascular toxicity.

A Novel Ruthenium-based Molecular Sensor to Detect Endothelial Nitric Oxide

Nitric oxide (NO) is a key regulator of endothelial cell and vascular function. The direct measurement of NO is challenging due to its short half-life, and as such surrogate measurements are typically used to approximate its relative concentrations. Here we demonstrate that ruthenium-based [Ru(bpy)₂(dabpy)]²⁺ is a potent sensor for NO in its irreversible, NO-bound active form, [Ru(bpy)₂(T-bpy)]²⁺. Using spectrophotometry we established the sensor’s ability to detect and measure soluble NO in a concentration-dependent manner in cell-free media. Endothelial cells cultured with acetylcholine or hydrogen peroxide to induce endogenous NO production showed modest increases of 7.3 ± 7.1% and 36.3 ± 25.0% respectively in fluorescence signal from baseline state, while addition of exogenous NO increased their fluorescence by 5.2-fold. The changes in fluorescence signal were proportionate and comparable against conventional NO assays. Rabbit blood samples immediately exposed to [Ru(bpy)₂(dabpy)]²⁺ displayed 8-fold higher mean fluorescence, relative to blood without sensor. Approximately 14% of the observed signal was NO/NO adduct-specific. Optimal readings were obtained when sensor was added to freshly collected blood, remaining stable during subsequent freeze-thaw cycles. Clinical studies are now required to test the utility of [Ru(bpy)₂(dabpy)]²⁺ as a sensor to detect changes in NO from human blood samples in cardiovascular health and disease.

Particulate Matter Air Pollution: Effects on the Cardiovascular System

Air pollution is a complex mixture of gaseous and particulate components, each of which has detrimental effects on human health. While the composition of air pollution varies greatly depending on the source, studies from across the world have consistently shown that air pollution is an important modifiable risk factor for significantly increased morbidity and mortality. Moreover, clinical studies have generally shown a greater impact of particulate matter (PM) air pollution on health than the gaseous components. PM has wide-ranging deleterious effects on human health, particularly on the cardiovascular system. Both acute and chronic exposure to PM air pollution is associated with increased risk of death from cardiovascular diseases including ischemic heart disease, heart failure, and ischemic/thrombotic stroke. Particulate matter has also been shown to be an important endocrine disrupter, contributing to the development of metabolic diseases such as obesity and diabetes mellitus, which themselves are risk factors for cardiovascular disease. While the epidemiological evidence for the deleterious effects of PM air pollution on health is increasingly accepted, newer studies are shedding light on the mechanisms by which PM exerts its toxic effects. A greater understanding of how PM exerts toxic effects on human health is required in order to prevent and minimize the deleterious health effects of this ubiquitous environmental hazard. Air pollution is a growing public health problem and mortality due to air pollution is expected to double by 2050. Here, we review the epidemiological evidence for the cardiovascular effects of PM exposure and discuss current understanding about the biological mechanisms, by which PM exerts toxic effects on cardiovascular system to induce cardiovascular disease.

PM2.5 impairs neurobehavior by oxidative stress and myelin sheaths injury of brain in the rat

Air particulate matter (PM) is a serious environmental problem that has been found to cause neuropathological disorders. Although the general toxicity of PM2.5 has been intensively studied, its neurobehavior effects are poorly discussed. In this study, we aim to investigate whether different exposure time of PM2.5 influence neurobehavior of rats, induce oxidative stress, histopathologic abnormalities, apoptosis, or changes of mitochondria and myelin. The results reveal that exposure to PM2.5 impaired spatial learning and memory, inquiring ability, as well as sensory function. These alterations were related to ultrastructure changes of mitochondria and myelin sheaths, abnormal expression of apoptosis-related proteins (Caspase-3, Caspase-9). These results provide a basis for a better understanding of myelin abnormality-related neurobehavior impairment in response to PM2.5.

miRNAs deregulation in lung cells exposed to airborne particulate matter (PM10) is associated with pathways deregulated in lung tumors

Particulate matter (PM) is an environmental pollutant that has been associated with an increased risk for lung cancer. PM exposure induces cellular alterations and the deregulation of cell signaling pathways. However other mechanisms such as microRNAs deregulation, might be involved in the development and progression of some types of epithelial cancer. The aim of this work was to evaluate miRNA expression in epithelial lung cells after exposure to PM₁₀ and to identify the possible gene targets of deregulated miRNAs. We measured the expression of 2538 miRNAs using a microarray platform after 72 h of PM₁₀ exposure; the potential biological function was inferred with bioinformatics analysis and we validated the relative expression of 10 selected miRNAs with real-time PCR. We found that the expression of 74 miRNAs was significantly changed: 45 miRNAs were downregulated and were involved in proliferation, cell cycle, cytoskeleton modification and autophagy; meanwhile, 29 miRNAs related to apoptosis, DNA damage repair and xenobiotic metabolism were upregulated.

Effects of prenatal exposure to air pollution on preeclampsia in Shenzhen, China

The impact of ambient air pollution on pregnant women is a concern in China. However, little is known about the association between air pollution and preeclampsia and the potential modifying effects of meteorological conditions have not been assessed. This study aimed to assess the effects of prenatal exposure to air pollution on preeclampsia, and to explore whether temperature and humidity modify the effects. We performed a retrospective cohort study based on 1.21 million singleton births from the birth registration system in Shenzhen, China, between 2005 and 2012. Daily average measurements of particulate matter <10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), air temperature (T), and dew point (T_d) were collected. Logistic regression models were performed to estimate associations between air pollution and preeclampsia during the first and second trimesters, and during the entire pregnancy. In each time window, we observed a positive gradient of increasing preeclampsia risk with increasing quartiles of PM₁₀ and SO₂ exposure. When stratified by T and T_d in three categories (<5th, 5th -95th, and >95th percentile), we found a significant interaction between PM₁₀ and T_d on preeclampsia; the adverse effects of PM₁₀ increased with T_d. During the entire pregnancy, there was a null association between PM₁₀ and preeclampsia under T_d < 5th percentile. Preeclampsia risk increased by 23% (95% CI: 19-26%) when 5th < T_d < 95th percentile, and by 34% (16-55%) when T_d > 95th percentile. We also found that air pollution effects on preeclampsia in autumn/winter seasons were stronger than those in the spring/summer. This is the first study to address modifying effects of meteorological factors on the association between air pollution and preeclampsia. Findings indicate that prenatal exposure to PM₁₀ and SO₂ increase preeclampsia risk in Shenzhen, China, and the effects could be modified by humidity. Pregnant women should limit air pollution exposure, particularly during humid periods.

Effects on IL-1β signaling activation induced by water and organic extracts of fine particulate matter (PM2.5) in vitro

Fine particulate matter (PM_2.5) air pollution poses a major risk to human health worldwide, and absorbed chemicals play a key role in determining the toxicity of PM_2.5. After inhalation and entry into the lungs, PM_2.5 components induce pro-inflammatory cytokines (e.g., interleukin (IL)-1β) in pulmonary cells. To test whether PM_2.5 components induce IL-1β through signing pathways that include the toll-like receptor 4 (TLR4)/nuclear factor-κ-gene binding (NF-κB), nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3), we exposed the mouse macrophage cell-line RAW264.7 to both water and organic extracts of PM_2.5 sampled over a 1-year period in Beijing, China. Varying degrees of oxidative stress and inflammatory responses were induced following exposure, while organic extracts of PM_2.5 collected during the heating season induced more significant responses. This response is attributed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) originating from coal combustion and biomass burning for domestic heating. The inhibition of signaling molecules suggested that increased IL-1β was associated with the TLR4/NF-κB pathway and NLRP3 inflammasome activation, with a slightly difference between water and organic extracts exposure groups, which was likely the result of different chemical components. Our study elucidated a potentially important mechanism by which PM_2.5 components could trigger pulmonary inflammation, thus improving our understanding of the deleterious effects of this important and prevalent form of air pollution.

Protective effects of Paeoniflorin against AOPP-induced oxidative injury in HUVECs by blocking the ROS-HIF-1α/VEGF pathway

BACKGROUND

Paeoniflorin, a monoterpene glycoside, exerts protective vascular effects, showing good antioxidant properties. However, whether Paeoniflorin has protective effect against the oxidative damage induced by advanced oxidation protein products (AOPPs) in Human umbilical vein endothelial cells (HUVECs) is unknown, as is the underlying mechanism.

PURPOSE

The present study was designed to investigate the effect of Paeoniflorin on oxidative damage of HUVECs and elucidate its underlying molecular mechanisms.

METHODS

The fluorescence intensity of 2', 7'-dichlorofluorescein-diacetate (DCFH-DA) staining was detected for intracellular reactive oxygen species (ROS) production. The increases mitochondrial membrane potential (MMP) was measured via flow cytometry and confocal microscopy using MitoTracker® Deep Red/ MitoTracker® Green staining. The intracellular adenosine triphosphate (ATP) was measured by ATP Determination Kit according to the manufacturer's protocol. Nox2, Nox4, hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and nuclear factor-κB (NF-κB) p65 expressions were detected by western blot.

RESULTS

Our results showed that Paeoniflorin increases MMP and ATP levels of HUVECs induced by AOPPs, and attenuates NF-κB p65 expression on HUVECs might mainly result from its antioxidant capability by suppressing ROS production. Moreover, we also found that Paeoniflorin can suppress HIF-1α and VEGF protein expression through a decrease of ROS production via down-regulation of Nox2/Nox4 expression in HUVECs. AOPP-induced RAGE mRNA up-regulation was blocked by Paeoniflorin treatment in HUVECs.

CONCLUSION

Our results provided the first experimental that Paeoniflorin protects against AOPP-induced oxidative damage in HUVECs, mainly through a mechanism involving a decrease in ROS production by the inhibition of Nox2/Nox4 and RAGE expression; restored ATP depletion and mitochondria dysfunction via ROS suppression; and down-regulated HIF-1α/VEGF, possibly via the ROS-NF-κB axis.

Role of oxidative stress in cardiovascular disease outcomes following exposure to ambient air pollution

Exposure to ambient air pollution is associated with adverse cardiovascular outcomes. These are manifested through several, likely overlapping, pathways including at the functional level, endothelial dysfunction, atherosclerosis, pro-coagulation and alterations in autonomic nervous system balance and blood pressure. At numerous points within each of these pathways, there is potential for cellular oxidative imbalances to occur. The current review examines epidemiological, occupational and controlled exposure studies and research employing healthy and diseased animal models, isolated organs and cell cultures in assessing the importance of the pro-oxidant potential of air pollution in the development of cardiovascular disease outcomes. The collective body of data provides evidence that oxidative stress (OS) is not only central to eliciting specific cardiac endpoints, but is also implicated in modulating the risk of succumbing to cardiovascular disease, sensitivity to ischemia/reperfusion injury and the onset and progression of metabolic disease following ambient pollution exposure. To add to this large research effort conducted to date, further work is required to provide greater insight into areas such as (a) whether an oxidative imbalance triggers and/or worsens the effect and/or is representative of the consequence of disease progression, (b) OS pathways and cardiac outcomes caused by individual pollutants within air pollution mixtures, or as a consequence of inter-pollutant interactions and (c) potential protection provided by nutritional supplements and/or pharmacological agents with antioxidant properties, in susceptible populations residing in polluted urban cities.

Maternal exposure to ambient PM2.5 exaggerates fetal cardiovascular maldevelopment induced by homocysteine in rats

Maternal exposure to airborne particulate matter with aerodynamic diameter <2.5 µm (PM_2.5 ) during pregnancy and lactation periods is associated with filial congenital cardiovascular diseases. This study aimed to investigate the toxic effects of maternal exposure to ambient levels of PM_2.5 on filial cardiovascular maldevelopment induced by homocysteine. Using a 2 × 2 factorial design, rats were randomized into four groups and were exposed to ambient PM_2.5 or filtered air (FA) throughout the pregnancy and lactation periods coupled with the administration of either homocysteine (HCY) or normal saline (NS) daily from gestation days 8-10. Morphological changes in the heart, myocardial apoptosis, expressions of cardiac progenitor transcriptional factors, and levels of cytokines were investigated in the offspring. The apoptosis-like changes in the myocardium were seen in the FA plus HCY-treated group and more obviously in the PM_2.5 plus HCY-treated group, which was in accordance with an increased myocardial apoptosis rate in the two groups. PM_2.5 exposure resulted in significantly decreased Nkx2-5 protein level and GATA4 and Nkx2-5 mRNA expressions, and significantly increased TNF-α and IL-1β levels. There were significant interactions between PM_2.5 exposure and HCY-treatment that PM_2.5 exposure reduced Nkx2-5 protein levels and GATA4 and Nkx2-5 mRNA expressions in the HCY-treated groups. These results suggest that maternal exposure to PM_2.5 , even at the ambient levels in urban regions in China, exaggerates filial cardiovascular maldevelopment induced by HCY in a murine model, exacerbating structural abnormalities in the filial cardiac tissue, which is possibly associated with oxidative stress and reduced GATA4 and Nkx2-5 transcription factor expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 877-889, 2017.

Air particulate matter induced oxidative stress and inflammation in cardiovascular disease and atherosclerosis: The role of Nrf2 and AhR-mediated pathways

Air particulate matter (PM) is an important component of air pollution, which has been reported to play important role in the adverse health effects of the latter. Extensive experimental data and epidemiological studies have shown that the increased cardiovascular morbidity and mortality and atherosclerosis caused by air pollution are mainly due to the PM component. Implicated in these adverse health effects of PM, is their ability to induce oxidative stress and pro-inflammatory events in the vascular system. The association between the cardiovascular ischemic events and atherosclerosis induced by PM has been linked to the ultrafine and fine components. These particles have a high content of redox cyclic chemicals. This, together with their ability to combine with proatherogenic molecules enhanced tissue oxidative stress. Studies have shown that the oxidative stress induced by PM could up-regulates the expression of phase I and phase II metabolize enzymes. This up-regulation occurs by the activation of transcription factors (such as nuclear factor (erythroid-derived 2) -like 2-related factor (Nrf2) and aryl hydrocarbon receptor (AhR)). This review will focus on data supporting the role of oxidative stress and inflammation in PM-induced cardiovascular diseases and atherosclerosis and the importance of Nrf2-and AhR- dependent regulatory pathways in the PM-induced cardiovascular events and atherosclerosis.

Secretome derived from breast tumor cell lines alters the morphology of human umbilical vein endothelial cells

Metastases, responsible for most of the solid tumor associated deaths, require angiogenesis and changes in endothelial cells. In this work, the effect of the secretomes of three breast tumor cell lines (MCF-7, MDA-MB-231 and ZR-75-30) on human umbilical vein endothelial cells (HUVEC) morphology was investigated. HUVEC treated with secretomes from breast cells were analyzed by confocal and time-lapse microscopy. Secretomes from ZR-75-30 and MDA-MB-231 cells modify the morphology and adhesion of HUVEC. These changes may provoke the loss of endothelial monolayer integrity. In consequence, tumor cells could have an increased access to circulation, which would then enhance metastasis.

Titanium dioxide nanoparticles induce the expression of early and late receptors for adhesion molecules on monocytes

BACKGROUND

There is growing evidence that exposure to titanium dioxide nanoparticles (TiO2 NPs) could be harmful. Previously, we have shown that TiO2 NPs induces endothelial cell dysfunction and damage in glial cells. Considering that inhaled particles can induce systemic effects and the evidence that nanoparticles may translocate out of the lungs, we evaluated whether different types of TiO2 NPs can induce the expression of receptors for adhesion molecules on monocytes (U937 cell line). We evaluated the role of reactive oxygen spices (ROS) on these effects.

METHODS

The expression of receptors for early (sLe(x) and PSGL-1) and late (LFA-1, VLA-4 and αVβ3) adhesion molecules was evaluated in U937 cells on a time course (3-24 h) using a wide range of concentrations (0.001-100 μg/mL) of three types of TiO2 NPs (<25 nm anatase, 50 nm anatase-rutile or < 100 nm anatase). Cells exposed to TNFα were considered positive controls, and unexposed cells, negative controls. In some experiments we added 10 μmolar of N-acetylcysteine (NAC) to evaluate the role of ROS.

RESULTS

All tested particles, starting at a concentration of 0.03 μg/mL, induced the expression of receptors for early and late adhesion molecules. The largest increases were induced by the different molecules after 3 h of exposure for sLe(x) and PSGL-1 (up to 3-fold of the positive controls) and after 18 h of exposure for LFA-1, VLA-4 and αVβ3 (up to 2.5-fold of the positive controls). Oxidative stress was observed as early as 10 min after exposure, but the maximum peak was found after 4 h of exposure. Adhesion of exposed or unexposed monocytes to unexposed or exposed endothelial cells was tested, and we observed that monocytes cells adhere in similar amounts to endothelial cells if one of the two cell types, or both were exposed. When NAC was added, the expression of the receptors was inhibited.

CONCLUSIONS

These results show that small concentrations of particles may activate monocytes that attach to endothelial cells. These results suggest that distal effects can be induced by small amounts of particles that may translocate from the lungs. ROS play a central role in the induction of the expression of these receptors.

Advantages of pure platelet-rich plasma compared with leukocyte- and platelet-rich plasma in promoting repair of bone defects

Background

High levels of pro-inflammatory cytokines in leukocyte- and platelet-rich plasma (L-PRP) may activate the nuclear factor κB (NF-κB) pathway to counter the beneficial effect of the growth factors on bone regeneration. However, to date, no relevant studies have substantiated this.

Methods

L-PRP and pure platelet-rich plasma (P-PRP) were isolated. The in vitro effects of L-PRP and P-PRP on the proliferation, viability and migration of human bone marrow-derived mesenchymal stem cells (HBMSCs) and EaHy926, tube formation of EaHy926, and osteogenic differentiation of HBMSCs were assessed by cell counting, flow cytometry, scratch assay, tube formation assay, and real-time quantitative polymerase chain reaction (RT-PCR), western blotting and Alizarin red staining, respectively. The in vitro effects of L-PRP and P-PRP on the nuclear translocation of NF-κB p65, mRNA expression of inducible nitric oxide synthase and cyclooxygenase-2, and production of prostaglandin E2 and nitric oxid were assessed by western blotting, RT-PCR, enzyme-linked immunosorbent assay and Griess reaction, respectively. The in vivo effects of L-PRP or P-PRP preprocessed β-tricalcium phosphate (β-TCP) on the calvarial defects in rats were assessed by histological and immunofluorescence examinations.

Results

P-PRP, which had similar platelet and growth factors concentrations but significantly lower concentrations of leukocytes and pro-inflammatory cytokines compared with L-PRP, promoted the proliferation, viability and migration of HBMSCs and EaHy926, tube formation of EaHy926 and osteogenic differentiation of HBMSCs in vitro, compared with L-PRP. The implantation of P-PRP preprocessed β-TCP also yielded better histological results than the implantation of L-PRP preprocessed β-TCP in vivo. Moreover, L-PRP treatment resulted in the activation of the NF-κB pathway in HBMSCs and EaHy926 in vitro while the postoperative delivery of caffeic acid phenethyl ester, an inhibitor of NF-κB activation, enhanced the histological results of the implantation of L-PRP preprocessed β-TCP in vivo.

Conclusions

Leukocytes in L-PRP may activate the NF-κB pathway via the increased pro-inflammatory cytokines to induce the inferior effects on bone regeneration of L-PRP compared with P-PRP. Hence, P-PRP may be more suitable for bone regeneration compared with L-PRP, and the combined use of P-PRP and β-TCP represents a safe, simple, and effective alternative option for autogenous bone graft in the treatment of bone defects.

Fine particulate matter in acute exacerbation of COPD

Chronic obstructive pulmonary disease (COPD) is a common airway disorder. In particular, acute exacerbations of COPD (AECOPD) can significantly reduce pulmonary function. The majority of AECOPD episodes are attributed to infections, although environmental stress also plays a role. Increasing urbanization and associated air pollution, especially in developing countries, have been shown to contribute to COPD pathogenesis. Elevated levels of particulate matter (PM) in polluted air are strongly correlated with the onset and development of various respiratory diseases. In this review, we have conducted an extensive literature search of recent studies of the role of PM_2.5 (fine PM) in AECOPD. PM_2.5 leads to AECOPD via inflammation, oxidative stress (OS), immune dysfunction, and altered airway epithelial structure and microbiome. Reducing PM_2.5 levels is a viable approach to lower AECOPD incidence, attenuate COPD progression and decrease the associated healthcare burden.

PM2.5 and Cardiovascular Diseases in the Elderly: An Overview

Background: Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in the elderly and the ambient concentration of PM_2.5 has been associated with several cardiovascular diseases. Methods: We describe the present state of planetary air pollution, analyze epidemiological studies linking PM_2.5 and CVD, and discuss multiple pathophysiological mechanisms linking PM_2.5 and CVD. Results: A few epidemiological studies show that the elderly appear specifically susceptible to adverse cardiovascular effects triggered by PM_2.5 exposure. Plausible pathophysiological mechanisms include inflammatory dysfunction, oxidative stress, abnormal activation of the hemostatic system and disturbance of the autonomic nervous system. Conclusions: An in-depth knowledge of the chemical compounds, pathophysiological mechanisms, and epidemiological studies of PM_2.5 are recommended to understand this important and modifiable factor contributing to geriatric CVD burden. We offer public health recommendations to reduce this preventable cause of disease and death.

Oxidative stress, apoptosis, and cell cycle arrest are induced in primary fetal alveolar type II epithelial cells exposed to fine particulate matter from cooking oil fumes

Epidemiological studies demonstrate a linkage between morbidity and mortality and particulate matter (PM), particularly fine particulate matter (PM2.5) that can readily penetrate into the lungs and are therefore more likely to increase the incidence of respiratory and cardiovascular diseases. The present study investigated the compositions of cooking oil fume (COF)-derived PM2.5, which is the major source of indoor pollution in China. Furthermore, oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest induced by COF-derived PM2.5 in primary fetal alveolar type II epithelial cells (AEC II cells) were also detected. N-acetyl-L-cysteine (NAC), a radical scavenger, was used to identify the role of oxidative stress in the abovementioned processes. Our results suggested that compositions of COF-derived PM2.5 are obviously different to PM2.5 derived from other sources, and COF-derived PM2.5 led to cell death, oxidative stress, apoptosis, and G0/G1 cell arrest in primary fetal AEC II cells. Furthermore, the results also showed that COF-derived PM2.5 induced apoptosis through the endoplasmic reticulum (ER) stress pathway, which is indicated by the increased expression of ER stress-related apoptotic markers, namely GRP78 and caspase-12. Besides, the induction of oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest was reversed by pretreatment with NAC. These findings strongly suggested that COF-derived PM2.5-induced toxicity in primary fetal AEC II cells is mediated by increased oxidative stress, accompanied by ER stress which results in apoptosis.

Particulate matter (PM₁₀) induces metalloprotease activity and invasion in airway epithelial cells

Airborne particulate matter with an aerodynamic diameter ≤ 10 μm (PM10) is a risk factor for the development of lung diseases and cancer. The aim of this work was to identify alterations in airway epithelial (A549) cells induced by PM10 that could explain how subtoxic exposure (10 μg/cm(2)) promotes a more aggressive in vitro phenotype. Our results showed that cells exposed to PM10 from an industrial zone (IZ) and an urban commercial zone (CZ) induced an increase in protease activity and invasiveness; however, the cell mechanism is different, as only PM10 from CZ up-regulated the activity of metalloproteases MMP-2 and MMP-9 and disrupted E-cadherin/β-catenin expression after 48 h of exposure. These in vitro findings are relevant in terms of the mechanism action of PM10 in lung epithelial cells, which could be helpful in understanding the pathogenesis of some human illness associated with highly polluted cities.

Toxicology of ambient particulate matter

It is becoming increasingly clear that inhalation exposure to particulate matter (PM) can lead to or exacerbate various diseases, which are not limited to the lung but extend to the cardiovascular system and possibly other organs and tissues. Epidemiological studies have provided strong evidence for associations with chronic obstructive pulmonary disease (COPD), asthma, bronchitis and cardiovascular disease, while the evidence for a link with lung cancer is less strong. Novel research has provided first hints that exposure to PM might lead to diabetes and central nervous system (CNS) pathology. In the current review, an overview is presented of the toxicological basis for adverse health effects that have been linked to PM inhalation. Oxidative stress and inflammation are discussed as central processes driving adverse effects; in addition, profibrotic and allergic processes are implicated in PM-related diseases. Effects of PM on key cell types considered as regulators of inflammatory, fibrotic and allergic mechanisms are described.

Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals

Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNA or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25μg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM.

Carbon black nanoparticles promote endothelial activation and lipid accumulation in macrophages independently of intracellular ROS production

Exposure to nanoparticles (NPs) may cause vascular effects including endothelial dysfunction and foam cell formation, with oxidative stress and inflammation as supposed central mechanisms. We investigated oxidative stress, endothelial dysfunction and lipid accumulation caused by nano-sized carbon black (CB) exposure in cultured human umbilical vein endothelial cells (HUVECs), THP-1 (monocytes) and THP-1 derived macrophages (THP-1a). The proliferation of HUVECs or co-cultures of HUVECs and THP-1 cells were unaffected by CB exposure, whereas there was increased cytotoxicity, assessed by the LDH and WST-1 assays, especially in THP-1 and THP-1a cells. The CB exposure decreased the glutathione (GSH) content in THP-1 and THP-1a cells, whereas GSH was increased in HUVECs. The reactive oxygen species (ROS) production was increased in all cell types after CB exposure. A reduction of the intracellular GSH concentration by buthionine sulfoximine (BSO) pre-treatment further increased the CB-induced ROS production in THP-1 cells and HUVECs. The expression of adhesion molecules ICAM-1 and VCAM-1, but not adhesion of THP-1 to HUVECs or culture dishes, was elevated by CB exposure, whereas these effects were unaffected by BSO pre-treatment. qRT-PCR showed increased VCAM1 expression, but no change in GCLM and HMOX1 expression in CB-exposed HUVECs. Pre-exposure to CB induced lipid accumulation in THP-1a cells, which was not affected by the presence of the antioxidant N-acetylcysteine. In addition, the concentrations of CB to induce lipid accumulation were lower than the concentrations to promote intracellular ROS production in THP-1a cells. In conclusion, exposure to nano-sized CB induced endothelial dysfunction and foam cell formation, which was not dependent on intracellular ROS production.