Exposure to biomass smoke extract enhances fibronectin release from fibroblasts

Third-Hand Exposure to E-Cigarette Vapour Induces Pulmonary Effects in Mice

In the last decade, e-cigarette usage has increased, with an estimated 82 million e-cigarette users globally. This is, in part, due to the common opinion that they are "healthier" than tobacco cigarettes or simply "water vapour". Third-hand e-vapour exposure is the chemical residue left behind from e-cigarette aerosols, which is of concern due to its invisible nature, especially among young children. However, there is limited information surrounding third-hand e-vapour exposure. This study aimed to investigate the pulmonary effects of sub-chronic third-hand e-vapour exposure in a murine model. BALB/c mice (4 weeks of age) were exposed to a towel containing nicotine free (0 mg) e-vapour, nicotine (18 mg) e-vapour, or no e-vapour (sham) and replaced daily for 4 weeks. At the endpoint, lung function was assessed, and bronchoalveolar lavage fluid and lungs were collected to measure inflammation and fibrosis. Mice exposed to third-hand e-vapour without nicotine had alveolar enlargement compared to sham exposed controls. Mice exposed to third-hand e-vapour with nicotine had reduced bronchial responsiveness to provocation, increased epithelial thickening in large airways, increased epithelial layers in small airways, alveolar enlargement, and increased small airway collagen deposition, compared to sham exposed controls. In conclusion, our study shows that third-hand e-vapour exposure, particularly in the presence of nicotine, negatively affects the lung health of mice and highlights the need for greater public awareness surrounding the dangers of third-hand exposure to e-cigarette vapour.

Development of Inhalable Spray Dried Nitrofurantoin Formulations for the Treatment of Emphysema

A central characteristic of emphysematous progression is the continuous destruction of the lung extracellular matrix (ECM). Current treatments for emphysema have only addressed symptoms rather than preventing or reversing the loss of lung ECM. Nitrofurantoin (NF) is an antibiotic that has the potential to induce lung fibrosis as a side effect upon oral administration. Our study aims to repurpose NF as an inhalable therapeutic strategy to upregulate ECM expression, thereby reversing the disease progression within the emphysematous lung. Spray-dried (SD) formulations of NF were prepared in conjunction with a two-fluid nozzle (2FN) and three-fluid nozzle (3FN) using hydroxypropyl methylcellulose (HPMC) and NF at 1:1 w/w. The formulations were characterized for their physicochemical properties (particle size, morphology, solid-state characteristics, aerodynamic behaviour, and dissolution properties) and characterized in vitro with efficacy studies on human lung fibroblasts. The 2FN formulation displayed a mass mean aerodynamic diameter (MMAD) of 1.8 ± 0.05 µm and fine particle fraction (FPF) of 87.4 ± 2.8% with significantly greater deposition predicted in the lower lung region compared to the 3FN formulation (MMAD: 4.4 ± 0.4 µm; FPF: 40 ± 5.8%). Furthermore, drug dissolution studies showed that NF released from the 2FN formulation after 3 h was significantly higher (55.7%) as compared to the 3FN formulation (42.4%). Importantly, efficacy studies in human lung fibroblasts showed that the 2FN formulation induced significantly enhanced ECM protein expression levels of periostin and Type IV Collagen (203.2% and 84.2% increase, respectively) compared to untreated cells, while 3FN formulations induced only a 172.5% increase in periostin and a 38.1% increase in type IV collagen. In conclusion, our study highlights the influence of nozzle choice in inhalable spray-dried formulations and supports the feasibility of using SD NF prepared using 2FN as a potential inhalable therapeutic agent to upregulate ECM protein production.

Mechanisms of Lung Damage and Development of COPD Due to Household Biomass-Smoke Exposure: Inflammation, Oxidative Stress, MicroRNAs, and Gene Polymorphisms

Chronic exposure to indoor biomass smoke from the combustion of solid organic fuels is a major cause of disease burden worldwide. Almost 3 billion people use solid fuels such as wood, charcoal, and crop residues for indoor cooking and heating, accounting for approximately 50% of all households and 90% of rural households globally. Biomass smoke contains many hazardous pollutants, resulting in household air pollution (HAP) exposure that often exceeds international standards. Long-term biomass-smoke exposure is associated with Chronic Obstructive Pulmonary Disease (COPD) in adults, a leading cause of morbidity and mortality worldwide, chronic bronchitis, and other lung conditions. Biomass smoke-associated COPD differs from the best-known cigarette smoke-induced COPD in several aspects, such as a slower decline in lung function, greater airway involvement, and less emphysema, which suggests a different phenotype and pathophysiology. Despite the high burden of biomass-associated COPD, the molecular, genetic, and epigenetic mechanisms underlying its pathogenesis are poorly understood. This review describes the pathogenic mechanisms potentially involved in lung damage, the development of COPD associated with wood-derived smoke exposure, and the influence of genetic and epigenetic factors on the development of this disease.

Wood Smoke Extract Promotes Extracellular Matrix Remodeling in Normal Human Lung Fibroblasts

Wood smoke (WS) contains many harmful compounds, including polycyclic aromatic hydrocarbons (PAHs). WS induces inflammation in the airways and lungs and can lead to the development of various acute and chronic respiratory diseases. Pulmonary fibroblasts are the main cells involved in the remodeling of the extracellular matrix (ECM) during the WS-induced inflammatory response. Although fibroblasts remain in a low proliferation state under physiological conditions, they actively participate in ECM remodeling during the inflammatory response in pathophysiological states. Consequently, we used normal human lung fibroblasts (NHLFs) to assess the potential effects of the PAHs-containing wood smoke extract (WSE) on the growth rate, total collagen synthesis, and the expression levels of collagen I and III, matrix metalloproteinase (MMP)-1, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, and the transforming growth factor (TGF)-β1. We also assessed MMPs activity. The results showed that WSE induced a trimodal behavior in the growth rate curves in NHLFs; the growth rate increased with 0.5-1 % WSE and decreased with 2.5% WSE, without causing cell damage; 5-20% WSE inhibited the growth and induced cell damage. After 3 hours of exposure, 2.5% WSE induced an increase in total collagen synthesis and upregulation of TGF-β1, collagen I and III, MMP-1, TIMP-1, and TIMP-2 expression. However, MMP-2 expression was downregulated and MMP-9 was not expressed. The gelatinase activity of MMP-2 was also increased. These results suggest that WSE affects the ECM remodeling in NHLFs and indicate the potential involvement of PAHs in this process.

Air pollution and cardiovascular disease: Can the Australian bushfires and global COVID-19 pandemic of 2020 convince us to change our ways?

Air pollution is a major global challenge for a multitude of reasons. As a specific concern, there is now compelling evidence demonstrating a causal relationship between exposure to airborne pollutants and the onset of cardiovascular disease (CVD). As such, reducing air pollution as a means to decrease cardiovascular morbidity and mortality should be a global health priority. This review provides an overview of the cardiovascular effects of air pollution and uses two major events of 2020-the Australian bushfires and COVID-19 pandemic lockdown-to illustrate the relationship between air pollution and CVD. The bushfires highlight the substantial human and economic costs associated with elevations in air pollution. Conversely, the COVID-19-related lockdowns demonstrated that stringent measures are effective at reducing airborne pollutants, which in turn resulted in a potential reduction in cardiovascular events. Perhaps one positive to come out of 2020 will be the recognition that tough measures are effective at reducing air pollution and that these measures have the potential to stop thousands of deaths from CVD.

Mitochondrial dynamics and mitophagy in lung disorders

Mitochondria are biosynthetic, bioenergetic, and signaling organelles which are critical for physiological adaptations and cellular stress responses to the environment. Various endogenous and environmental stress affects critical processes in mitochondrial homeostasis such as oxidative phosphorylation, biogenesis, mitochondrial redox system which leads to the formation of reactive oxygen species (ROS) and free radicals. The state of function of the mitochondrion is particularly dependent on the dynamic balance between mitochondrial biogenesis, fusion and fission, and degradation of damaged mitochondria by mitophagy. Increasing evidence has suggested a prominent role of mitochondrial dysfunction in the onset and progression of various lung pathologies, ranging from acute to chronic disorders. In this comprehensive review, we discuss the emerging findings of multifaceted regulations of mitochondrial dynamics and mitophagy in normal lung homeostasis as well as the prominence of mitochondrial dysfunction as a determining factor in different lung disorders such as lung cancer, COPD, IPF, ALI/ARDS, BPD, and asthma. The review will contribute to the existing understanding of critical molecular machinery regulating mitochondrial dynamic state during these pathological states. Furthermore, we have also highlighted various molecular checkpoints involved in mitochondrial dynamics, which may serve as hopeful therapeutic targets for the development of potential therapies for these lung disorders.

Sexually dimorphic production of interleukin-6 in respiratory disease

Diverging susceptibility and severity in respiratory diseases is prevalent between males and females. Sex hormones have inconclusively been attributed as the cause of these differences, however, strong evidence exists promoting genetic factors leading to sexual dimorphism. As such, we investigate differential proinflammatory cytokine (interleukin (IL)‐6 and CXCL8) release from TNF‐α stimulated primary human lung fibroblasts in vitro. We present, for the first time, in vitro evidence supporting clinical findings of differential production of IL‐6 between males and females across various respiratory diseases. IL‐6 was found to be produced approximately two times more from fibroblasts derived from females compared to males. As such we demonstrate sexual dimorphism in cytokine production of IL‐6 outside the context of biological factors in the human body. As such, our data highlight that differences exist between males and females in the absence of sex hormones. We, for the first time, demonstrate inherent in vitro differences exist between males and females in pulmonary fibroblasts.

Airway Remodeling in Asthma

Asthma is an inflammatory disease of the airways that may result from exposure to allergens or other environmental irritants, resulting in bronchoconstriction, wheezing, and shortness of breath. The structural changes of the airways associated with asthma, broadly referred to as airway remodeling, is a pathological feature of chronic asthma that contributes to the clinical manifestations of the disease. Airway remodeling in asthma constitutes cellular and extracellular matrix changes in the large and small airways, epithelial cell apoptosis, airway smooth muscle cell proliferation, and fibroblast activation. These pathological changes in the airway are orchestrated by crosstalk of different cell types within the airway wall and submucosa. Environmental exposures to dust, chemicals, and cigarette smoke can initiate the cascade of pro-inflammatory responses that trigger airway remodeling through paracrine signaling and mechanostimulatory cues that drive airway remodeling. In this review, we explore three integrated and dynamic processes in airway remodeling: (1) initiation by epithelial cells; (2) amplification by immune cells; and (3) mesenchymal effector functions. Furthermore, we explore the role of inflammaging in the dysregulated and persistent inflammatory response that perpetuates airway remodeling in elderly asthmatics.

Crucial role for lung iron level and regulation in the pathogenesis and severity of asthma

Accumulating evidence highlights links between iron regulation and respiratory disease. Here, we assessed the relationship between iron levels and regulatory responses in clinical and experimental asthma.We show that cell-free iron levels are reduced in the bronchoalveolar lavage (BAL) supernatant of severe or mild-moderate asthma patients and correlate with lower forced expiratory volume in 1 s (FEV₁). Conversely, iron-loaded cell numbers were increased in BAL in these patients and with lower FEV₁/forced vital capacity (FVC) ratio. The airway tissue expression of the iron sequestration molecules divalent metal transporter 1 (DMT1) and transferrin receptor 1 (TFR1) are increased in asthma, with TFR1 expression correlating with reduced lung function and increased Type-2 (T2) inflammatory responses in the airways. Furthermore, pulmonary iron levels are increased in a house dust mite (HDM)-induced model of experimental asthma in association with augmented Tfr1 expression in airway tissue, similar to human disease. We show that macrophages are the predominant source of increased Tfr1 and Tfr1⁺ macrophages have increased Il13 expression. We also show that increased iron levels induce increased pro-inflammatory cytokine and/or extracellular matrix (ECM) responses in human airway smooth muscle (ASM) cells and fibroblasts ex vivo and induce key features of asthma in vivo, including airway hyper-responsiveness (AHR) and fibrosis, and T2 inflammatory responses.Together these complementary clinical and experimental data highlight the importance of altered pulmonary iron levels and regulation in asthma, and the need for a greater focus on the role and potential therapeutic targeting of iron in the pathogenesis and severity of disease.

Critical role for iron accumulation in the pathogenesis of fibrotic lung disease

Increased iron levels and dysregulated iron homeostasis, or both, occur in several lung diseases. Here, the effects of iron accumulation on the pathogenesis of pulmonary fibrosis and associated lung function decline was investigated using a combination of murine models of iron overload and bleomycin-induced pulmonary fibrosis, primary human lung fibroblasts treated with iron, and histological samples from patients with or without idiopathic pulmonary fibrosis (IPF). Iron levels are significantly increased in iron overloaded transferrin receptor 2 (Tfr2) mutant mice and homeostatic iron regulator (Hfe) gene-deficient mice and this is associated with increases in airway fibrosis and reduced lung function. Furthermore, fibrosis and lung function decline are associated with pulmonary iron accumulation in bleomycin-induced pulmonary fibrosis. In addition, we show that iron accumulation is increased in lung sections from patients with IPF and that human lung fibroblasts show greater proliferation and cytokine and extracellular matrix responses when exposed to increased iron levels. Significantly, we show that intranasal treatment with the iron chelator, deferoxamine (DFO), from the time when pulmonary iron levels accumulate, prevents airway fibrosis and decline in lung function in experimental pulmonary fibrosis. Pulmonary fibrosis is associated with an increase in Tfr1⁺ macrophages that display altered phenotype in disease, and DFO treatment modified the abundance of these cells. These experimental and clinical data demonstrate that increased accumulation of pulmonary iron plays a key role in the pathogenesis of pulmonary fibrosis and lung function decline. Furthermore, these data highlight the potential for the therapeutic targeting of increased pulmonary iron in the treatment of fibrotic lung diseases such as IPF. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Dietary Fatty Acids Amplify Inflammatory Responses to Infection through p38 MAPK Signaling

Obesity is an important risk factor for severe asthma exacerbations, which are mainly caused by respiratory infections. Dietary fatty acids, which are increased systemically in obese patients and are further increased after high-fat meals, affect the innate immune system and may contribute to dysfunctional immune responses to respiratory infection. In this study we investigated the effects of dietary fatty acids on immune responses to respiratory infection in pulmonary fibroblasts and a bronchial epithelial cell line (BEAS-2B). Cells were challenged with BSA-conjugated fatty acids (ω-6 polyunsaturated fatty acids [PUFAs], ω-3 PUFAs, or saturated fatty acids [SFAs]) +/- the viral mimic polyinosinic:polycytidylic acid (poly[I:C]) or bacterial compound lipoteichoic acid (LTA), and release of proinflammatory cytokines was measured. In both cell types, challenge with arachidonic acid (AA) (ω-6 PUFA) and poly(I:C) or LTA led to substantially greater IL-6 and CXCL8 release than either challenge alone, demonstrating synergy. In epithelial cells, palmitic acid (SFA) combined with poly(I:C) also led to greater IL-6 release. The underlying signaling pathways of AA and poly(I:C)- or LTA-induced cytokine release were examined using specific signaling inhibitors and IB. Cytokine production in pulmonary fibroblasts was prostaglandin dependent, and synergistic upregulation occurred via p38 mitogen-activated protein kinase signaling, whereas cytokine production in bronchial epithelial cell lines was mainly mediated through JNK and p38 mitogen-activated protein kinase signaling. We confirmed these findings using rhinovirus infection, demonstrating that AA enhances rhinovirus-induced cytokine release. This study suggests that during respiratory infection, increased levels of dietary ω-6 PUFAs and SFAs may lead to more severe airway inflammation and may contribute to and/or increase the severity of asthma exacerbations.

Inflammatory health effects of indoor and outdoor particulate matter

Inflammation is a common and essential event in the pathogenesis of diverse diseases. Decades of research has converged on an understanding that all combustion-derived particulate matter (PM) is inflammatory to some extent in the lungs and also systemically, substantially explaining a significant portion of the massive cardiopulmonary disease burden associated with these exposures. In general, this means that efforts to do the following can all be beneficial: reduce particulates at the source, decrease the inflammatory potential of PM output, and, where PM inhalation is unavoidable, administer anti-inflammatory treatment. A range of research, including basic illumination of inflammatory pathways, assessment of disease burden in large cohorts, tailored treatment trials, and epidemiologic, animal, and in vitro studies, is highlighted in this review. However, meaningful translation of this research to decrease the burden of disease and deliver a clear and cohesive message to guide daily clinical practice remains rudimentary. Ongoing efforts to better understand substantial differences in the concentration and type of PM to which the global community is exposed and then distill how that influences inflammation promises to have real-world benefit. This review addresses this complex topic in 3 sections, including ambient PM (typically associated with ground-level transportation), wildfire-induced PM, and PM from indoor biomass burning. Recognizing the overlap between these domains, we also describe differences and suggest future directions to better inform clinical practice and public health.

Soluble Wood Smoke Extract Promotes Barrier Dysfunction in Alveolar Epithelial Cells through a MAPK Signaling Pathway

Wildfire smoke induces acute pulmonary distress and is of particular concern to risk groups such as the sick and elderly. Wood smoke (WS) contains many of the same toxic compounds as those found in cigarette smoke (CS) including polycyclic aromatic hydrocarbons, carbon monoxide, and free radicals. CS is a well-established risk factor for respiratory diseases such as asthma and COPD. Limited studies investigating the biological effects of WS on the airway epithelium have been performed. Using a cell culture-based model, we assessed the effects of a WS-infused solution on alveolar epithelial barrier function, cell migration, and survival. The average geometric mean of particles in the WS was 178 nm. GC/MS analysis of the WS solution identified phenolic and cellulosic compounds. WS exposure resulted in a significant reduction in barrier function, which peaked after 24 hours of continuous exposure. The junctional protein E-cadherin showed a prominent reduction in response to increasing concentrations of WS. Furthermore, WS significantly repressed cell migration following injury to the cell monolayer. There was no difference in cell viability following WS exposure. Mechanistically, WS exposure induced activation of the p44/42, but not p38, MAPK signaling pathway, and inhibition of p44/42 phosphorylation prevented the disruption of barrier function and loss of E-cadherin staining. Thus, WS may contribute to the breakdown of alveolar structure and function through a p44/42 MAPK-dependent pathway and may lead to the development and/or exacerbation of respiratory pathologies with chronic exposure.

The role of environmental exposure to non-cigarette smoke in lung disease

Chronic exposure to household indoor smoke and outdoor air pollution is a major contributor to global morbidity and mortality. The majority of these deaths occur in low and middle-income countries. Children, women, the elderly and people with underlying chronic conditions are most affected. In addition to reduced lung function, children exposed to biomass smoke have an increased risk of developing lower respiratory tract infections and asthma-related symptoms. In adults, chronic exposure to biomass smoke, ambient air pollution, and opportunistic exposure to fumes and dust are associated with an increased risk of developing chronic bronchitis, chronic obstructive pulmonary disease (COPD), lung cancer and respiratory infections, including tuberculosis. Here, we review the evidence of prevalence of COPD in people exposed to non-cigarette smoke. We highlight mechanisms that are likely involved in biomass-smoke exposure-related COPD and other lung diseases. Finally, we summarize the potential preventive and therapeutic strategies for management of COPD induced by non-cigarette smoke exposure.

Kidney damage induced by sub-chronic fine particulate matter exposure

According to the WHO, about 3 million people die each year due to ambient air pollution. Most of the in vivo studies on the PM_2.5 effects have been done on respiratory and cardiovascular tissues. However, little is known about the effects on the tissues involved on xenobiotic removal, such as kidneys. In the present study we assess the harmful effects of sub-chronic exposure to PM_2.5 on the kidney, by investigating histologic and serum alterations in healthy and hypertensive rat models. Mean PM_2.5 concentrations during exposures were slightly above the daily WHO standard. Exposed animals showed fibrosis, mesangial expansion, decrease glomerular and tubular lumen volumes in kidneys, with an elevated BUN. Hypertensive animals also exhibited much more severe alterations than healthy animals. We conclude that PM_2.5 induces minimal or small-scale abnormalities that can be determinant for renal health preservation.

Short-chain fatty acids increase TNFα-induced inflammation in primary human lung mesenchymal cells through the activation of p38 MAPK

Short-chain fatty acids (SCFAs), produced as by-products of dietary fiber metabolism by gut bacteria, have anti-inflammatory properties and could potentially be used for the treatment of inflammatory diseases, including asthma. The direct effects of SCFAs on inflammatory responses in primary human lung mesenchymal cells have not been assessed. We investigated whether SCFAs can protect against tumor necrosis factor (TNF)α-induced inflammation in primary human lung fibroblasts (HLFs) and airway smooth muscle (ASM) cells in vitro. HLFs and ASM cells were exposed to SCFAs, acetate (C2:0), propionate (C3:0), and butyrate (C4:0) (0.01-25 mM) with or without TNFα, and the release of proinflammatory cytokines, IL-6, and CXCL8 was measured using ELISA. We found that none of the SCFAs suppressed TNFα-induced cytokine release. On the contrary, challenge with supraphysiological concentrations (10-25 mM), as might be used therapeutically, of propionate or butyrate in combination with TNFα resulted in substantially greater IL-6 and CXCL8 release from HLFs and ASM cells than challenge with TNFα alone, demonstrating synergistic effects. In ASM cells, challenge with acetate also enhanced TNFα-induced IL-6, but not CXCL8 release. Synergistic upregulation of IL-6 and CXCL8 was mediated through the activation of free fatty acid receptor (FFAR)3, but not FFAR2. The signaling pathways involved were further examined using specific inhibitors and immunoblotting, and responses were found to be mediated through p38 MAPK signaling. This study demonstrates that proinflammatory, rather than anti-inflammatory effects of SCFAs are evident in lung mesenchymal cells.

Dietary ω-6 polyunsaturated fatty acid arachidonic acid increases inflammation, but inhibits ECM protein expression in COPD

Background

The obesity paradox in COPD describes protective effects of obesity on lung pathology and inflammation. However, the underlying relationships between obesity, diet and disease outcomes in COPD are not fully understood. In this study we measured the response to dietary fatty acids upon markers of inflammation and remodelling in human lung cells from people with and without COPD.

Methods

Pulmonary fibroblasts were challenged with ω-3 polyunsaturated fatty acids (PUFAs), ω-6 PUFAs, saturated fatty acids (SFAs) or the obesity-associated cytokine TNFα. After 48–72 h release of the pro-inflammatory cytokines interleukin (IL)-6 and CXCL8 was measured using ELISA and mRNA expression and deposition of the extracellular matrix (ECM) proteins fibronectin, type I collagen, tenascin and perlecan were measured using qPCR or ECM ELISA, respectively.

Results

Challenge with the ω-6 PUFA arachidonic acid (AA), but not ω-3 PUFAs or SFAs, resulted in increased IL-6 and CXCL8 release from fibroblasts, however IL-6 and CXCL8 release was reduced in COPD (n = 19) compared to non-COPD (n = 36). AA-induced cytokine release was partially mediated by downstream mediators of cyclooxygenase (COX)-2 in both COPD and non-COPD. In comparison, TNFα-induced IL-6 and CXCL8 release was similar in COPD and non-COPD, indicating a specific interaction of AA in COPD. In patients with or without COPD, regression analysis revealed no relationship between BMI and cytokine release. In addition, AA, but not SFAs or ω-3 PUFAs reduced the basal deposition of fibronectin, type I collagen, tenascin and perlecan into the ECM in COPD fibroblasts. In non-COPD fibroblasts, AA-challenge decreased basal deposition of type I collagen and perlecan, but not fibronectin and tenascin.

Conclusions

This study shows that AA has disease-specific effects on inflammation and ECM protein deposition. The impaired response to AA in COPD might in part explain why obesity appears to have less detrimental effects in COPD, compared to other lung diseases.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0919-4) contains supplementary material, which is available to authorized users.

Dietary omega-6, but not omega-3, polyunsaturated or saturated fatty acids increase inflammation in primary lung mesenchymal cells

Obesity is an important risk factor for developing severe asthma. Dietary fatty acids, which are increased in sera of obese individuals and after high-fat meals, activate the innate immune system and induce inflammation. This study investigated whether dietary fatty acids directly cause inflammation and/or synergize with obesity-induced cytokines in primary human pulmonary fibroblasts in vitro. Fibroblasts were challenged with BSA-conjugated fatty acids [ω-6 polyunsaturated fatty acids (PUFAs) and ω-3 PUFAs or saturated fatty acids (SFAs)], with or without TNF-α, and release of the proinflammatory cytokines, IL-6 and CXCL8, was measured. We found that the ω-6 PUFA arachidonic acid (AA), but not ω-3 PUFAs or SFAs, upregulates IL-6 and CXCL8 release. Combined AA and TNF-α challenge resulted in substantially greater cytokine release than either alone, demonstrating synergy. Synergistic upregulation of IL-6, but not CXCL8, was mainly mediated via cyclooxygenase (COX). Inhibition of p38 MAPK reduced CXCL8 release, induced by AA and TNF-α alone, but not in combination. Synergistic CXCL8 release, following AA and TNF-α challenge, was not medicated via a single signaling pathway (MEK1, JNK, phosphoinositide 3-kinase, and NF-κB) nor by hyperactivation of NF-κB or p38. To investigate if these findings occur in other airway cells, effects of AA in primary human airway smooth muscle (ASM) cells and human bronchial epithelial cells were also investigated. We found proinflammatory effects in ASM cells but not epithelial cells. This study suggests that diets rich in ω-6 PUFAs might promote airway inflammation via multiple pathways, including COX-dependent and -independent pathways, and in an obese person, may lead to more severe airway inflammation.

The effects of CXCL10 polymorphisms on COPD susceptibility

The polymorphisms of cytokine genes has been reported to modulate the individual's susceptibility to environmental stimuli in COPD development. C-X-C motif chemokine 10 (CXCL10) mediates recruitment inflammatory cells such as monocytes. Therefore, it may play a key role in COPD. Here, a case-control study was conducted to evaluate the association between CXCL10 tag-SNPs and COPD risk. Four tag-SNPs including rs4256246, rs4508917, rs56061981, and rs56316945 were identified based on the linkage disequilibrium (LD) analysis in 30 healthy controls. The associations between these four tag-SNPs and COPD risk were further evaluated in 480 COPD cases and 488 controls. We found that the "T" allele of rs56061981 was significantly associated with reducing risk of COPD, while "G" allele of rs56316945 was significantly associated with increasing risk of COPD. SNP rs56316945 was significantly associated with increasing risk of COPD under different models except recessive model after adjusting the sex, age, pack year, and biomass. SNP rs56061981 was significantly associated with decreasing COPD risk under different models except recessive model after adjusting the sex, age, pack year, and biomass. Stratified analysis of smoking status and biomass with SNPs supported rs56061981 may interact with biomass and smoking thus modulate COPD susceptibility and rs56216945 was apparently associated with the severity of pulmonary function of COPD patients. This study suggests that rs56061981 and rs56216945 in CXCL10 gene promoter contribute COPD susceptibility.

Influence of involuntary cigarette smoke inhalation on osseointegration: a systematic review and meta-analysis of preclinical studies

There are no studies that have systematically reviewed the influence of involuntary cigarette smoke inhalation (ICSI) on the stability of implants. The aim of the present study was to perform a systematic review and meta-analysis of preclinical studies that assessed the influence of involuntary cigarette smoke inhalation ICSI on osseointegration. Indexed databases (PubMed, Google-Scholar, Scopus, EMBASE, and Web of Knowledge) were searched till September 2017. Titles and abstracts of studies identified using the above-described protocol were independently screened by 2 authors. Full-texts of studies judged by title and abstract to be relevant were independently evaluated for the stated eligibility criteria. Nine studies were included. Six studies showed that ICSI compromised bone area contact around implants. In 4 studies, peri-implant bone mineral density was significantly higher in the control group than among subjects exposed to ICSI. For the effects of ICSI on the osseointegration of dental implants, significant differences could be observed for bone-to-implant contact for test subjects in cancellous (Z=-4.08, p<0.001) and cortical bone (Z=-4.31, p<0.001) respectively. ICSI may negatively influence osseointegration of dental implants. It is imperative to educate patients about the negative effects of passive smoking on dental and systemic health.

Evidence of Biomass Smoke Exposure as a Causative Factor for the Development of COPD

Chronic obstructive pulmonary disease (COPD) is a progressive disease of the lungs characterised by chronic inflammation, obstruction of airways, and destruction of the parenchyma (emphysema). These changes gradually impair lung function and prevent normal breathing. In 2002, COPD was the fifth leading cause of death, and is estimated by the World Health Organisation (WHO) to become the third by 2020. Cigarette smokers are thought to be the most at risk of developing COPD. However, recent studies have shown that people with life-long exposure to biomass smoke are also at high risk of developing COPD. Most common in developing countries, biomass fuels such as wood and coal are used for cooking and heating indoors on a daily basis. Women and children have the highest amounts of exposures and are therefore more likely to develop the disease. Despite epidemiological studies providing evidence of the causative relationship between biomass smoke and COPD, there are still limited mechanistic studies on how biomass smoke causes, and contributes to the progression of COPD. This review will focus upon why biomass fuels are used, and their relationship to COPD. It will also suggest methodological approaches to model biomass exposure in vitro and in vivo.

Cigarette Smoking-Induced Cardiac Hypertrophy, Vascular Inflammation and Injury Are Attenuated by Antioxidant Supplementation in an Animal Model

Background: Cardiovascular diseases are the leading causes of morbidity and mortality worldwide. Cigarette smoking remains a global health epidemic with associated detrimental effects on the cardiovascular system. In this work, we investigated the effects of cigarette smoke exposure on cardiovascular system in an animal model. The study then evaluated the effects of antioxidants (AO), represented by pomegranate juice, on cigarette smoke induced cardiovascular injury. This study aims at evaluating the effect of pomegranate juice supplementation on the cardiovascular system of an experimental rat model of smoke exposure.

Methods: Adult rats were divided into four different groups: Control, Cigarette smoking (CS), AO, and CS + AO. Cigarette smoke exposure was for 4 weeks (5 days of exposure/week) and AO group received pomegranate juice while other groups received placebo. Assessment of cardiovascular injury was documented by assessing different parameters of cardiovascular injury mediators including: (1) cardiac hypertrophy, (2) oxidative stress, (3) expression of inflammatory markers, (4) expression of Bradykinin receptor 1 (Bdkrb1), Bradykinin receptor 2 (Bdkrb2), and (5) altered expression of fibrotic/atherogenic markers [(Fibronectin (Fn1) and leptin receptor (ObR))].

Results: Data from this work demonstrated that cigarette smoke exposure induced cardiac hypertrophy, which was reduced upon administration of pomegranate in CS + AO group. Cigarette smoke exposure was associated with elevation in oxidative stress, significant increase in the expression of IL-1β, TNFα, Fn1, and ObR in rat's aorta. In addition, an increase in aortic calcification was observed after 1 month of cigarette smoke exposure. Furthermore, cigarette smoke induced a significant up regulation in Bdkrb1 expression level. Finally, pomegranate supplementation exhibited cardiovascular protection assessed by the above findings and partly contributed to ameliorating cardiac hypertrophy in cigarette smoke exposed animals.

Conclusion: Findings from this work showed that cigarette smoking exposure is associated with significant cardiovascular pathology such as cardiac hypertrophy, inflammation, pro-fibrotic, and atherogenic markers and aortic calcification in an animal model as assessed 1 month post exposure. Antioxidant supplementation prevented cardiac hypertrophy and attenuated indicators of atherosclerosis markers associated with cigarette smoke exposure.

Biomass smoke exposure and chronic lung disease

PURPOSE OF REVIEW

Approximately 3 billion people worldwide rely on coal and biomass fuel for cooking and heating. Biomass smoke exposure is associated with several chronic lung diseases, including chronic obstructive pulmonary disease (COPD), asthma-COPD overlap syndrome, usual interstitial pneumonitis, hut lung, and bronchial anthracofibrosis. Household air pollution primarily from biomass smoke is the biggest risk factor for COPD worldwide. Despite the significant burden of biomass smoke-related respiratory disease, the exposure is still underappreciated worldwide, especially in high-income countries.

RECENT FINDINGS

Recent literature highlights the immunoinflammatory differences between biomass smoke-related COPD and tobacco smoke-related COPD that may lead to better understanding of the differences in the clinical phenotypes between the two entities, suggests an association with the recently recognized asthma-COPD overlap syndrome, and elucidates the burden of disease in high-income countries.

SUMMARY

The current review focuses on the association between biomass smoke and common chronic respiratory diseases, discuss differences between biomass smoke-related COPD and tobacco smoke-related COPD, highlights chronic respiratory diseases that are specific for biomass smoke exposure such as hut lung and bronchial anthracofibrosis, and discusses the known impact of beneficial interventions.

Biomass smoke as a risk factor for chronic obstructive pulmonary disease: effects on innate immunity

Chronic obstructive pulmonary disease (COPD), a major cause of mortality and morbidity worldwide, is considered an archetypical disease of innate immunity, where inhaled particles and gases trigger an inflammatory response, favoring tissue proliferation in small airways and tissue destruction in lung parenchyma, in addition to the recruitment of immune cells to these compartments. Although cigarette smoking is still considered the main risk factor for developing COPD, the trend of proposing biomass smoke (BS) exposure as a principal risk factor is gaining importance, as around 3 billion people worldwide are exposed to this pollutant daily. A considerable amount of evidence has shown the potential of BS as an enhancer of lung inflammation. However, an impairment of some innate immune responses after BS exposure has also been described. Regarding the mechanisms by which biomass smoke alters the innate immune responses, three main classes of cell surface receptors-the TLRs, the scavenger receptors and the transient receptor potential channels-have shown the ability to transduce signals initiated after BS exposure. This article is an updated and comprehensive review of the immunomodulatory effects described after the interaction of BS components with these receptors.

Aclidinium bromide combined with formoterol inhibits remodeling parameters in lung epithelial cells through cAMP

Combined muscarinic receptor antagonists and long acting β2-agonists improve symptom control in chronic obstructive pulmonary disease (COPD) significantly. In clinical studies aclidinium bromide achieved better beneficial effects than other bronchodilators; however, the underlying molecular mechanisms are unknown. This study assessed the effect of aclidinium bromide combined with formoterol on COPD lung (n=20) and non-COPD lung (n=10) derived epithelial cells stimulated with TGF-β1+carbachol on: (i) the generation of mesenchymal cells in relation to epithelial cells, (II) extracellular matrix (ECM) deposition, and (iii) the interaction of ECM on the generation of epithelial and mesenchymal cells. TGF-β1+carbachol enhanced the generation of mesenchymal cells, which was significantly reduced by aclidinium bromide or formoterol. The effect of combined drugs was additive. Inhibition of p38 MAP kinase and Smad by specific inhibitors or aclidinium bromide reduced the generation of mesenchymal cells. In mesenchymal cells, TGF-β1+carbachol induced the deposition of collagen-I and fibronectin which was prevented by both drugs dose-dependently. Formoterol alone reduced collagen-I deposition via cAMP, this however, was overruled by TGF-β1+carbachol and rescued by aclidinium bromide. Inhibition of fibronectin was cAMP independent, but involved p38 MAP kinase and Smad. Seeding epithelial cells on ECM collagen-I and fibronectin induced mesenchymal cell generation, which was reduced by aclidinium bromide and formoterol. Our results suggest that the beneficial effect of aclidinium bromide and formoterol involves cAMP affecting both, the accumulation of mesenchymal cells and ECM remodeling, which may explain the beneficial effect of the drugs on lung function in COPD.

Pathogenic mechanisms in chronic obstructive pulmonary disease due to biomass smoke exposure

Chronic obstructive pulmonary disease (COPD) mortality and morbidity have increased significantly worldwide in recent decades. Although cigarette smoke is still considered the main risk factor for the development of the disease, estimates suggest that between 25% and 33% of COPD patients are non-smokers. Among the factors that may increase the risk of developing COPD, biomass smoke has been proposed as one of the most important, affecting especially women and children in developing countries. Despite the epidemiological evidence linking exposure to biomass smoke with adverse health effects, the specific cellular and molecular mechanisms by which this pollutant can be harmful for the respiratory and cardiovascular systems remain unclear. In this article we review the main pathogenic mechanisms proposed to date that make biomass smoke one of the major risk factors for COPD.

Fibronectin predicts the outcome of acute-on-chronic hepatitis B liver failure

BACKGROUND

Acute-on-chronic hepatitis B liver failure (ACHBLF) is a serious condition with varied etiologies and manifestations, and is associated with a high mortality rate. Fibronectin is involved in a number of biological processes, including cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing and ischemic injury. Serum fibronectin concentrations may provide prognostic information in ACHBLF; however, as a prognostic marker of mortality in patients with ACHBLF, it needs further validation.

METHODS

The aim of this study was to examine whether admission levels of fibronectin in ACHBLF patients are correlated with outcomes. In this prospective study, 78 ACHBLF patients were compared to 70 matched healthy controls. Fibronectin levels were determined using a commercial enzyme-linked immunosorbent assay kit to determine the prognostic value of fibronectin levels on admission.

RESULTS

The median (range) fibronectin level at admission for ACHBLF patients was significantly reduced compared with that of healthy controls (142 [62-275] mg/l vs 265 [190-346] mg/l, respectively; p<0.001). Fibronectin levels were significantly higher in surviving patients than in those who died (155 [70-275] mg/l vs 119 [62-235] mg/l; p=0.020). Receiver operating characteristic curve analysis showed that a cut-off level of 135 mg/l was the best prognostic indicator, yielding positive and negative predictive values of 60% (18/30) and 71% (30/42), respectively.

CONCLUSIONS

Our results suggested that decreased serum fibronectin levels in patients with ACHBLF were correlated to hepatic injury and inflammation. However, because of the lack of specificity, the use of fibronectin as an independent prognostic indicator is limited.