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

Association between biomass exposure and COPD occurrence in Fez, Morocco: results from the BOLD study

OBJECTIVE

To investigate the association between biomass exposure and chronic obstructive pulmonary disease (COPD) in a representative sample of adults from the Moroccan population METHODS: A cross-sectional study was conducted in Fez as part of the Burden of Obstructive Lung Disease (BOLD) study, which included apparently healthy subjects aged 40 years and above. Biomass exposure was defined as self-report use of various biomass types for heating or cooking. The Wood Heating Exposure Index, and the Cooking Biomass Exposure Index were used to assess biomass exposure. Participants underwent post-bronchodilator spirometry and COPD was defined as having a forced expiratory volume in 1 s/forced vital capacity ratio <0.7. Descriptive, univariate and multivariable statistical analyses adjusting for potential confounders including age, sex, smoking, education level, Mokken scale (wealth index) and occupational dust exposure were performed for the general population and separately for men and women.

RESULTS

A total of 760 subjects were included, comprising 350 men and 410 women. In the multivariable analyses, we found a statistically significant association between a higher Wood Heating Exposure Index and COPD in men (adjusted OR=3.8; 95% CI: 1.4 to 10.4). While for women, a high Cooking Biomass Exposure Index was the main factor potentially linked to the increased risk of COPD (adjusted OR=7.2; 95% CI: 1.7 to 30.0).

CONCLUSION

This study suggests that biomass exposure is a significant risk factor for COPD development in both men and women, independently of the smoking status which is known as its main risk factor.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Comprehensive epigenomic profiling of human alveolar epithelial differentiation identifies key epigenetic states and transcription factor co-regulatory networks for maintenance of distal lung identity

BACKGROUND

Disruption of alveolar epithelial cell (AEC) differentiation is implicated in distal lung diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung adenocarcinoma that impact morbidity and mortality worldwide. Elucidating underlying disease pathogenesis requires a mechanistic molecular understanding of AEC differentiation. Previous studies have focused on changes of individual transcription factors, and to date no study has comprehensively characterized the dynamic, global epigenomic alterations that facilitate this critical differentiation process in humans.

RESULTS

We comprehensively profiled the epigenomic states of human AECs during type 2 to type 1-like cell differentiation, including the methylome and chromatin functional domains, and integrated this with transcriptome-wide RNA expression data. Enhancer regions were drastically altered during AEC differentiation. Transcription factor binding analysis within enhancer regions revealed diverse interactive networks with enrichment for many transcription factors, including NKX2-1 and FOXA family members, as well as transcription factors with less well characterized roles in AEC differentiation, such as members of the MEF2, TEAD, and AP1 families. Additionally, associations among transcription factors changed during differentiation, implicating a complex network of heterotrimeric complex switching in driving differentiation. Integration of AEC enhancer states with the catalog of enhancer elements in the Roadmap Epigenomics Mapping Consortium and Encyclopedia of DNA Elements (ENCODE) revealed that AECs have similar epigenomic structures to other profiled epithelial cell types, including human mammary epithelial cells (HMECs), with NKX2-1 serving as a distinguishing feature of distal lung differentiation.

CONCLUSIONS

Enhancer regions are hotspots of epigenomic alteration that regulate AEC differentiation. Furthermore, the differentiation process is regulated by dynamic networks of transcription factors acting in concert, rather than individually. These findings provide a roadmap for understanding the relationship between disruption of the epigenetic state during AEC differentiation and development of lung diseases that may be therapeutically amenable.

Effect of Antioxidants in the Treatment of COPD Patients: Scoping Review

Chronic obstructive pulmonary disease (COPD) is a common, preventable, treatable lung disease characterized by persistent respiratory symptoms and airflow limitation and multiorgan impact. This affects the nutritional status of patients and requires multidimensional interventions including nutritional interventions according to individual metabolic needs. Our scoping review determined the effects of antioxidants in the treatment of COPD patients and their role in the decrease in the probability of exacerbations, hospital readmissions, and changes in lung function. The sources MEDLINE, LILACS, and Google Scholar were consulted and 19 studies were selected. The most indicated antioxidants are N-Acetylcysteine, vitamins E and D, and Zinc. Other antioxidants from plants or fruits extracts are also being investigated. The beneficial effect of antioxidants in stable or exacerbated patients is not clear, but theoretical and biological arguments of benefit justify lines of research that specify the impact on reducing oxidative stress and negative effects in COPD.

Lung Features in Individuals with Biomass Smoke Exposure Characterized by CT Scan and Changes in Pulmonary Function

Background and Objective

To determine the effects of BSE (biomass smoke exposure) on pulmonary and non-pulmonary changes in patients with COPD compared with normal individuals.

Methods

Using a cohort, we recruited 16 healthy individuals with BSE (BSE normal), 19 patients with BSE+COPD, 13 healthy individuals with cigarette smoke exposure (CSE normal), 25 patients with CSE+COPD, and 25 healthy controls. Patients with GOLD stage I and II COPD were included. Baseline data (demographic data, BSE or CSE, lung function, and CT findings) and follow-up lung function data were collected. CT parameters of emphysema, pulmonary small vessels, airway remodeling, pectoralis muscles, and erector spinae muscle were measured.

Results

Individuals with BSE were mainly women (32/35, 91.43%). Compared with the CSE+COPD group, the BSE+COPD group demonstrated slower lung function decline, increased lower lung emphysema, narrower airway lumen dimensions and increased airway wall thickening in the moderate and small airways (all P<0.05). Compared with healthy controls, the CSE normal and BSE normal groups exhibited significant reductions in pulmonary small vessel area and obvious airway remodeling in small airways (P<0.05). Compared with the BSE normal group, the BSE+COPD group showed significantly more severe emphysema and airway remodeling, as well as reduced left pectoralis major muscle area (all P<0.05).

Conclusion

Healthy individuals with BSE had reduced pulmonary small vessel area and evidence of airway remodeling; patients with BSE and COPD showed more severe emphysema, airway remodeling, and reductions in pectoralis major muscle area.

Clinical Trial Registration

ChiCTR-OO-14004264.

Differences between cigarette smoking and biomass smoke exposure: An in silico comparative assessment of particulate deposition in the lungs

Cigarette smoking and biomass smoke are the two main environmental risk factors of chronic obstructive pulmonary disease (COPD) worldwide. However, it remains unclear why these exposures result in two different disease phenotypes. In this study, we assessed the lung deposition from biomass and cigarette smoke exposures and examined whether differences due to inherently different particle size distributions and inhalation conditions may contribute to the differences between biomass- and tobacco-related COPD phenotypes. Using high-fidelity three-dimensional computational fluid-particle dynamics in a representative upper airway geometry, coupled to one-dimensional models of the lower airways, we computed total deposited doses and examined regional deposition patterns based on exposure data from a randomized control trial in Peru and from the literature for biomass and mainstream cigarette smoke, respectively. Our results showed that intrathoracic deposition was higher in cigarette smoking, with 36.8% of inhaled biomass smoke particles and 57.7% of cigarette smoke particles depositing in the intrathoracic airways. We observed higher fractions of cigarette smoke particles in the last few airway generations, which could explain why cigarette smoking is associated with more emphysema than biomass smoke exposure. Mean daily deposited dose was two orders of magnitude higher in cigarette smoking. Lobar distributions of the deposited dose also differed, with the left lower and right upper lobes receiving the highest doses of biomass and cigarette smoke particles, respectively. Our findings suggest that the differences between biomass- and tobacco-related COPD could, at least in part, be due to differences in total and regional lung deposition of biomass and cigarette smoke.

A comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women in Tamilnadu, India

It is of interest to document data on the comparative analysis of biomass and clean fuel exposure on pulmonary function during cooking among rural women. The study consisted of 100 biomass and 100 LPG fuel using women with no smoking habits and other related illness Parameters such as FVC, FEV1, FEV1/FVC, PEFR, FEF25-75%were obtained using the computerized spirometry to assess the pulmonary function in these subjects. The collected data were analyzed using the Student t-test method and Pearson correlation. The exposure index for biomass fuel users is 69.78±27.25 showing high exposure duration during cooking. The parameters for pulmonary functions significantly declined in FVC (42.34±13.6), FEV1 (45.55±15.98), PEFR (34.11±14.78) and FEF25-75% (45.56±23.00) for biomass fuel user. However, this is not true for FEV1/FVC ratio (107.56±16.9). The increase in PFT suggests the restrictive and obstructive patterns of pulmonary diseases. There was a negative correlation between increased duration of cooking and the value of FEV1/FVC (r = -0.2961), FEF25-75% (r = -0.3519) and PEFR (r = -0.2868). Thus, the deformation of pulmonary function due to extended exposure of biomass fuel for cooking women in rural Tamilnadu is shown using parameter features such as high exposure index, overcrowded area and improper ventilated houses.

Participation of HHIP Gene Variants in COPD Susceptibility, Lung Function, and Serum and Sputum Protein Levels in Women Exposed to Biomass-Burning Smoke

BACKGROUND

A variety of organic materials (biomass) are burned for cooking and heating purposes in poorly ventilated houses; smoke from biomass combustion is considered an environmental risk factor for chronic obstructive pulmonary disease COPD. In this study, we attempted to determine the participation of single-nucleotide variants in the HHIP (hedgehog-interacting protein) gene in lung function, HHIP serum levels, and HHIP sputum supernatant levels in Mexican women with and without COPD who were exposed to biomass-burning smoke.

METHODS

In a case-control study (COPD-BS, n = 186, BBES, n = 557) in Mexican women, three SNPs (rs13147758, rs1828591, and rs13118928) in the HHIP gene were analyzed by qPCR; serum and supernatant sputum protein levels were determined through ELISA.

RESULTS

The rs13118928 GG genotype is associated with decreased risk (p = 0.021, OR = 0.51, CI95% = 0.27-0.97) and the recessive genetic model (p = 0.0023); the rs1828591-rs13118928 GG haplotype is also associated with decreased risk (p = 0.04, OR = 0.65, CI95% 0.43-0.98). By the dominant model (rs13118928), the subjects with one or two copies of the minor allele (G) exhibited higher protein levels. Additionally, two correlations with the AG genotype were identified: BBES with FEV1 (p = 0.03, r2 = 0.53) and COPD-BS with FEV1/FVC (p = 0.012, r2 = 0.54).

CONCLUSIONS

Single-nucleotide variants in the HHIP gene are associated with decreased COPD risk, higher HHIP serum levels, and better lung function in Mexican women exposed to biomass burning.

The long-term outcomes of tobacco control strategies based on the cognitive intervention for smoking cessation in COPD patients

OBJECTIVE

To evaluate the long-term efficacy of tobacco control strategies based on cognitive intervention for smoking cessation in chronic obstructive pulmonary disease (COPD) patients, and to provide basis for clinical practice.

MATERIALS AND METHODS

102 COPD patients with a long-term history of smoking from the outpatient clinic were recruited in the study. These smokers were randomly divided into intervention group and control group. The intervention group received a cognitive intervention containing individual consultation, telephone follow-ups and self-help materials, etc. The prevalence of quitting smoking, acute exacerbation (AE), lung function and survival were compared in the groups in 10 years.

RESULTS

There were significant differences between the intervention group and the control group in the rate of persistent quitting smoking in half a year (17.6% vs 3.9%) (P < 0.05), the rate of quitting smoking at the 6th month (58.8% vs 33.3%) (P < 0.05). After 3 months (P < 0.01) and 6 months (P < 0.01), the difference in body weight between the intervention group and the control group was statistically significant. Intervention-group patients had fewer AE per year (P < 0.01) and higher FEV1/FVC ratio (P < 0.01) after 5-year and 10-year follow-up. Besides, the FEV1% predicted in the intervention patients was higher than that in control group after 10-year follow-up. The ages of patients in the death group were greater than those in the survival group. Death-group patients had longer smoking times, higher smoking index, and later onset of COPD symptoms. Death-group patients had lower FEV1% predicted (P < 0.05) and FEV1/FVC ratio (P < 0.01). During 10-year follow-up, 30 patient deaths were recorded (the control group: n = 48; 19 deaths, and intervention group: n = 46; 11 deaths), and patients in the control group had lower survival than those in the intervention group. (P < 0.05).

CONCLUSION

The method of quitting smoking based on cognitive intervention is an effective way for COPD patients to quit smoking successfully. Quitting smoking can slower deterioration in lung function and improve the survival of COPD patients.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2000031239 (Chinese clinical trial registry).

Amerindian Ancestry Influences Genetic Susceptibility to Chronic Obstructive Pulmonary Disease

The contribution of genetic ancestry on chronic obstructive pulmonary disease (COPD) predisposition remains unclear. To explore this relationship, we analyzed the associations between 754,159 single nucleotide polymorphisms (SNPs) and risk of COPD (n = 214 cases, 193 healthy controls) in Talca, Chile, considering the genetic ancestry and established risk factors. The proportion of Mapuche ancestry (PMA) was based on a panel of 45 Mapuche reference individuals. Five PRDM15 SNPs and two PPP1R12B SNPs were associate with COPD risk (p = 0.05 to 5×10^-4) in those individuals with lower PMA. Based on linkage disequilibrium and sliding window analyses, an adjacent PRDM15 SNPs were associated with COPD risk in the lower PMA group (p = 10^-3 to 3.77×10^-8). Our study is the first to report an association between PPP1R12B and COPD risk, as well as effect modification between ethnicity and PRDM15 SNPs in determining COPD risk. Our results are biologically plausible given that PPP1R12B and PRDM15 are involved in immune dysfunction and autoimmunity, providing mechanistic evidence for COPD pathogenesis and highlighting the importance to conduct more genome wide association studies (GWAS) in admixed populations with Amerindian descent.

Comparative study on respiratory function among rural women using biomass fuel and non-biomass fuel: evidence of a cross-sectional survey in Bangladesh

Respiratory diseases' mortality and morbidity have been a major public health burden primarily attributed to widespread exposure to indoor and outdoor pollutants in the environment. The study conducted among 510 Bangladeshi women residing in the northeastern zone of the Sylhet division from semi-urban and rural settings to compare the biomass fuel users (N = 255) with the non-biomass users (N = 255). It has been observed that all the symptoms had a higher prevalence among the women who were exposed to biomass fuel compared with those exposed to clean gas fuel. Women exposed to biomass group reported frequent cough and phlegm production episodes during a 3-month timeline before the survey period which was found statistically higher (p < 0.001) compared with that of the clean gas fuel group. Moreover, the use of biomass fuel has been associated with a significant decrease in forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and peak expiratory flow rate (PEFR). Appropriate strategies from stakeholders and government authorities in disseminating health hazards from biomass fuel along with supporting the community by providing alternative energy sources for cooking can largely impact people's lives.

The Role of Toll-Like Receptors 2 and 4 in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Currently, chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. The determination of immune mechanisms of inflammation in the disease presents an important challenge for fundamental medical research. According to modern views, Toll-like receptors (TLRs), among which TLR2 and TLR4 play a key role, are one of the essential components of inflammatory process in COPD. This review focuses on following aspects: the role of TLR2 and TLR4 in the initiation of inflammatory process in COPD; the mechanisms of influence of various exogenous factors (cigarette smoke, suspended particulate matter, and bacteria) on the expression of TLR2 and TLR4; the contribution of these TLRs to the T-helper (Th) immune response development in COPD, in particular to the Th17 immune response, which contributes to the progression of the disease and therapeutic implications of TLR2 and TLR4 in COPD.

Airborne Particulate Matter: Human Exposure and Health Effects

OBJECTIVE

Exposure to airborne particulate matter (PM) is estimated to cause millions of premature deaths annually. This work conveys known routes of exposure to PM and resultant health effects.

METHODS

A review of available literature.

RESULTS

Estimates for daily PM exposure are provided. Known mechanisms by which insoluble particles are transported and removed from the body are discussed. Biological effects of PM, including immune response, cytotoxicity, and mutagenicity, are reported. Epidemiological studies that outline the systemic health effects of PM are presented.

CONCLUSION

While the integrated, per capita, exposure of PM for a large fraction of the first-world may be less than 1 mg per day, links between several syndromes, including attention deficit hyperactivity disorder (ADHD), autism, loss of cognitive function, anxiety, asthma, chronic obstructive pulmonary disease (COPD), hypertension, stroke, and PM exposure have been suggested. This article reviews and summarizes such links reported in the literature.

Electrochemical methods for detection of biomarkers of Chronic Obstructive Pulmonary Disease in serum and saliva

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death nowadays, and its underdiagnosis is still a great challenge. More effective diagnosis method is in urgent need since the traditional spirometry has many limitations in the practical application. The electrochemical (EC) detection methods have their unique advantages of high accuracy, short response time and easy integration of the system. In this review, recent works on the EC methods for COPD biomarkers including interleukin 6 (IL-6), interleukin 8 (IL-8) and C-reactive protein (CRP) are summarized. Five types of EC methods are highlighted in this study, as enzyme-labelled immunosensors, nanoparticle-labelled immunosensors, capacitive or impedimetric immunosensors, magnetoimmunosensors, and field effect transistor (FET) immunosensors. To date, EC immunosensors have been exhibiting high analytical performance with a detection limit that can achieve several pg/mL or even lower. The simplicity of EC immunosensors makes them a perfect solution for a future point-of-care device to use in settings for COPD diagnosis and follow-up. Nevertheless, more efforts need to be paid on the simultaneous detection of multiple biomarkers, a demand for the clinical diagnosis, and processes of assay simplification towards achieving one-step detection.

Solid Fuel Use and Incident COPD in Chinese Adults: Findings from the China Kadoorie Biobank

BACKGROUND

Solid fuels are widely used in China. Household air pollution from the burning of solid fuels may increase the risk of chronic obstructive pulmonary disease (COPD), but prospective evidence is limited.

OBJECTIVES

We examined the association of solid fuel use for cooking and heating with the risk of COPD in a prospective cohort study.

METHODS

Participants were from the China Kadoorie Biobank. Current and previous fuels used for household cooking and heating were self-reported at baseline in 2004–2008. In the present study, "solid fuels" refers to coal and wood, whereas "cleaner fuels" refers to energy sources that presumably produce lower levels of indoor pollution, including electricity, gas, and central heating. A total of 475,827 adults 30–79 y of age without prevalent COPD were followed through the end of 2015. We used adjusted Cox regression models to estimate hazard ratios for COPD.

RESULTS

Over 9.1 y of follow-up, 9,835 incident COPD cases were reported. Compared with the use of cleaner fuels for cooking, using coal and wood for cooking was positively associated with COPD, with fully adjusted HRs of 1.06 (95% CI: 0.98, 1.15) and 1.14 (95% CI: 1.06, 1.23), respectively. Adjusted HRs for heating with coal and wood were 1.16 (95% CI: 1.04, 1.29) and 1.21 (95% CI: 1.09, 1.35), respectively. The positive association between cooking with solid fuel and COPD appeared to be limited to women and never- (vs. ever-) smokers. COPD risk increased with a higher number of years of solid fuel use for heating and wood use for cooking.

CONCLUSIONS

The use of solid fuel for cooking and heating was associated with the increased risk of COPD in this prospective cohort study. Studies with more accurate exposure assessment are needed to confirm the association. https://doi.org/10.1289/EHP2856.

The health and social implications of household air pollution and respiratory diseases

Approximately three billion individuals are exposed to household air pollution (HAP) from the burning of biomass fuels worldwide. Household air pollution is responsible for 2.9 million annual deaths and causes significant health, economic and social consequences, particularly in low- and middle-income countries. Although there is biological plausibility to draw an association between HAP exposure and respiratory diseases, existing evidence is either lacking or conflicting. We abstracted systematic reviews and meta-analyses for summaries available for common respiratory diseases in any age group and performed a literature search to complement these reviews with newly published studies. Based on the literature summarized in this review, HAP exposure has been associated with acute respiratory infections, tuberculosis, asthma, chronic obstructive pulmonary disease, pneumoconiosis, head and neck cancers, and lung cancer. No study, however, has established a causal link between HAP exposure and respiratory disease. Furthermore, few studies have controlled for tobacco smoke exposure and outdoor air pollution. More studies with consistent diagnostic criteria and exposure monitoring are needed to accurately document the association between household air pollution exposure and respiratory disease. Better environmental exposure monitoring is critical to better separate the contributions of household air pollution from that of other exposures, including ambient air pollution and tobacco smoking. Clinicians should be aware that patients with current or past HAP exposure are at increased risk for respiratory diseases or malignancies and may want to consider earlier screening in this population.

Risk of acute exacerbations in chronic obstructive pulmonary disease associated with biomass smoke compared with tobacco smoke

BACKGROUND

Risk of exacerbations in chronic obstructive pulmonary disease (COPD) associated with biomass smoke has not been well addressed, although biomass smoke is similar in composition to tobacco smoke.

METHODS

To investigate whether the risk of exacerbations in COPD associated with biomass smoke differs from that in COPD associated with tobacco smoke, we recruited patients with COPD from two Korean multicenter prospective cohorts. In a multiple linear regression model, the standardized regression coefficient (β) of biomass smoke exposure ≥25 years was most similar to that (β') of tobacco smoke exposure ≥10 pack-years (β = - 0.13 and β' = - 0.14). We grouped patients with COPD into four categories based on the above cut-offs: Less Tobacco-Less Biomass, Less Tobacco-More Biomass, More Tobacco-Less Biomass, and More Tobacco-More Biomass. The main outcome was the incidence of moderate or severe exacerbations.

RESULTS

Among 1033 patients with COPD, 107 were included in Less Tobacco-Less Biomass (mean age: 67 years, men: 67%), 40 in Less Tobacco-More Biomass (mean age: 70 years, men: 35%), 631 in More Tobacco-Less Biomass (mean age: 68 years, men: 98%), and 255 in More Tobacco-More Biomass (mean age: 69 years, men: 97%). The incidence rates of exacerbations were not significantly different between Less Tobacco-More Biomass and More Tobacco-Less Biomass (adjusted incidence rate ratio, 1.03; 95% confidence interval, 0.56-1.89; P = 0.921). No interaction between sex and tobacco and biomass smoke was observed. When propensity score matching with available covariates including age and sex was applied, a similar result was observed.

CONCLUSIONS

Patients with COPD associated with biomass smoke and those with COPD associated with tobacco smoke had a similar risk of exacerbations. This suggests that patients with COPD associated with biomass smoke should be treated actively.

Indoor air pollution exposure effects on lung and cardiovascular health in the High Himalayas, Nepal: An observational study

BACKGROUND

Exposure to indoor biomass fuel smoke is associated with increased morbidity and mortality. The aim of this study is to evaluate the association between exposure to indoor biomass burning and early pulmonary and cardiovascular damage.

METHODS

The indoor levels of particulate matter (PM) [PM₁₀, PM_2.5] and black carbon (BC) were monitored in 32 houses in a Himalayan village. Seventy-eight subjects were submitted to spirometry and cardiovascular evaluation [carotid to femoral pulse wave velocity (PWV) and echocardiography].

RESULTS

Peak indoor BC concentration up to 100 μg m^-3 and PM₁₀ - PM_2.5 up to 1945-592 μg m^-3 were measured. We found a non-reversible bronchial obstruction in 18% of subjects ≥40 yr; mean forced expiratory flow between 25% and 75% of the forced vital capacity (FEF_25-75) <80% in 54% of subjects, suggestive of early respiratory impairment, significantly and inversely related to age. Average BC was correlated with right ventricular-right atrium gradient (R = 0.449,p = .002), total peripheral resistances (TPR) (R = 0.313,p = .029) and PWV (R = 0.589,p < .0001) especially in subjects >30 yr. In multiple variable analysis, BC remained an independent predictor of PWV (β = 0.556,p = .001), and TPR (β = 0.366;p = .018).

CONCLUSIONS

Indoor pollution exposure is associated to early pulmonary and cardiovascular damages, more evident for longer duration and higher intensity exposure.

KIR/HLA Gene Profile Implication in Systemic Sclerosis Patients from Mexico

Introduction

Systemic Sclerosis (SSc) is an autoimmune, inflammatory, and multisystemic disease characterized by the presence of autoantibodies and fibrosis. The pathogenesis involves the interaction between immune system cells such as macrophages, NK cells, T cells, and B cells. Killer-cell Immunoglobulin-like Receptors (KIR) are expressed in NK cells and some T cell subsets that recognize HLA class I molecules as ligands and are involved in regulating the activation and inhibition of these cells. The KIR family consists of 14 genes and two pseudogenes; according to the gene content, the genotype could be AA and Bx. The aim of this study was to evaluate the association between KIR/HLA genes and genotypes with SSc and the clinical characteristics.

Methods

We included 50 SSc patients and 90 Control Subjects (CS). Genotyping of KIR, HLA-C, -Bw4, and -A^∗03/^∗11 was made by SSP-PCR.

Results

In SSc patients, a higher frequency of KIR2DL2 (p = 0.0007, p′ = 0.011), KIR2DS4del (p = 0.001, p′ = 0.021), and HLA-C2 (p = 0.02, p′ = 0.09) was found. This is the first study to evaluate the frequency of HLA-A^∗03/^∗11 in SSc patients, of which a low frequency was found in both groups. Compound genotypes KIR2DL2+/HLA-C1+ or KIR2DL2+/HLA-C2+ have a higher frequency in SSc patients. The Bx genotype was the most frequent and was associated with risk to SSc (p = 0.007, OR = 3.1, 95% CI = 1.4–7.9, p′ = 0.014). The genotypes with a higher iKIR number than aKIR (iKIR > aKIR) were found in all individuals; genotypes with 7-8 iKIR genes were increased in SSc patients. We do not find an association between the KIR genes with the clinical characteristics.

Conclusion

The results suggest that KIR2DL2 and 2DS4del could have a risk role in the development of SSc, but not with clinical manifestations.

Environmental Risks and Children's Health in a Mayan Community from Southeast of Mexico

BACKGROUND

The World Health Organization (WHO) estimates that 25% of global morbidity and one-third of childhood morbidity may be attributable to environment. Low and high-income countries displayed different environmental risks. Mexico demonstrates the necessity for creating a national environmental health program. In southeastern Mexico, Tixméhuac, is a Mayan community with a high marginalization degree and social backwardness. The main childhood morbidities are acute and chronic diseases.

OBJECTIVE

The aim of the study was to recognize environmental risks for children's health in Tixméhauc, Yucatan State.

METHODS

A total of one hundred children under five years old participated. To identify the environmental risks at home, items from the Green Sheet Guidance (WHO), Salamanca General Survey and Environmental Clinical History were used. To know the prevalence of respiratory diseases and asthma, the International Study of Asthma and Allergies in Children (ISAAC) survey was used. Potentially hazardous sites were identified partially using the Methodology for Identification and Evaluation of Health Hazards in Contaminated Sites from the Pan American Health Organization (PAHO).

FINDINGS

The low stature of, malnutrition, presence of wheezing and asthma symptoms in children were higher than expected. The suspected cases of parasitosis and vector-borne disease occurred in 50% of the children. Indoor air quality perception was associated with respiratory pathology history; housing quality was related to suspected cases of vector-borne diseases; drinking water quality was linked to suspected cases of parasitosis. Risk areas in the community include agricultural activity, which has led to deposits of empty containers of agrochemicals and electronic waste among solid waste dump.

CONCLUSION

This study presents observed environmental risks to children in a low development country and in developing countries. The community has a low perception of the environmental risk. The need for public health programs reducing risks to children's environmental health is imperative.

Association between Household Air Pollution Exposure and Chronic Obstructive Pulmonary Disease Outcomes in 13 Low- and Middle-Income Country Settings

RATIONALE

Forty percent of households worldwide burn biomass fuels for energy, which may be the most important contributor to household air pollution.

OBJECTIVES

To examine the association between household air pollution exposure and chronic obstructive pulmonary disease (COPD) outcomes in 13 resource-poor settings.

METHODS

We analyzed data from 12,396 adult participants living in 13 resource-poor, population-based settings. Household air pollution exposure was defined as using biomass materials as the primary fuel source in the home. We used multivariable regressions to assess the relationship between household air pollution exposure and COPD outcomes, evaluated for interactions, and conducted sensitivity analyses to test the robustness of our findings.

MEASUREMENTS AND MAIN RESULTS

Average age was 54.9 years (44.2-59.6 yr across settings), 48.5% were women (38.3-54.5%), prevalence of household air pollution exposure was 38% (0.5-99.6%), and 8.8% (1.7-15.5%) had COPD. Participants with household air pollution exposure were 41% more likely to have COPD (adjusted odds ratio, 1.41; 95% confidence interval, 1.18-1.68) than those without the exposure, and 13.5% (6.4-20.6%) of COPD prevalence may be caused by household air pollution exposure, compared with 12.4% caused by cigarette smoking. The association between household air pollution exposure and COPD was stronger in women (1.70; 1.24-2.32) than in men (1.21; 0.92-1.58).

CONCLUSIONS

Household air pollution exposure was associated with a higher prevalence of COPD, particularly among women, and it is likely a leading population-attributable risk factor for COPD in resource-poor settings.

Comparative analysis of COPD associated with tobacco smoking, biomass smoke exposure or both

Background

Exposure to noxious gases and particles contained in both tobacco smoking (TS) and biomass smoke (BS) are well recognized environmental risk factors for chronic obstructive pulmonary disease (COPD). COPD is characterized by an abnormal inflammatory response, both in the pulmonary and systemic compartments. The differential effects of TS, BS or their combined exposure have not been well characterized yet. This study sought to compare the lung function characteristics and systemic inflammatory response in COPD patients exposed to TS, BS or their combination.

Methods

Sociodemographic, clinical and lung functional parameters were compared across 49 COPD patients with a history of smoking and no BS exposure (TS COPD), 31 never-smoker COPD patients with BS exposure (BS COPD), 46 COPD patients with a combined exposure (TS + BS COPD) and 52 healthy controls (HC) who have never been exposed neither to TS or BS. Blood cell counts, C-reactive protein (CRP), fibrinogen and immunoglobulin E (IgE) levels were quantified in all four groups.

Results

TS + BS COPD patients exhibited significantly lower oxygen saturation than the rest of groups (p < 0.01). Spirometry and diffusing capacity were significantly higher in BS than in TS or TS + BS patients. CRP levels were significantly higher in TS COPD patients than in BS COPD group (p < 0.05), whereas fibrinogen was raised in COPD patients with a history of smoking (TS and TS + BS) when compared to control subjects (p < 0.01). Finally, COPD patients with BS exposure (BS and BS + TS groups) showed higher IgE levels than TS and HC (p < 0.05).

Conclusions

There are significant physiological and inflammatory differences between COPD patients with TS, BS and TS + BS exposures. The latter had worse blood oxygenation, whereas the raised levels of IgE in BS exposed patients suggests a differential Th2 systemic inflammatory pattern triggered by this pollutant.

The complications of treating chronic obstructive pulmonary disease in low income countries of sub-Saharan Africa

INTRODUCTION

In most low and middle-income countries, chronic obstructive pulmonary disease (COPD) is on the rise. Areas covered: Unfortunately, COPD is a neglected disease in these countries. Taking sub-Saharan Africa as an example, in rural areas, COPD is even unknown regarding public awareness and public health planning. Programs for the management of COPD are poorly developed, and the quality of care is often of a low standard. Inhaled medication is often not available or not affordable. Tobacco smoking is the most common encountered risk factor for COPD. However, in sub-Saharan Africa, household air pollution is another major risk factor for the development of COPD. Communities are also exposed to a variety of other risk factors, such as low birth weight, malnutrition, severe childhood respiratory infections, occupational exposures, outdoor pollution, human-immunodeficiency virus and tuberculosis. All these factors contribute to the high burden of poor respiratory health in sub-Saharan Africa. Expert commentary: A silent growing epidemic of COPD seems to be unravelling. Therefore, prevention and intervention programs must involve all the stakeholders and start as early as possible. More research is needed to describe, define and inform treatment approaches, and natural history of biomass-related COPD.

Smoking cessation affects the natural history of COPD

Background

Cigarette smoking is the most commonly encountered and readily identifiable risk factor for COPD. However, it is not clear which quantitative factors related to smoking influence the prognosis of COPD patients.

Methods

A total of 204 patients with a long-term history of smoking were enrolled into this study and followed up for 5 years. Patients were divided into “death” or “survival” groups based on follow-up results and “quitting-smoking” or “continuing-smoking” groups based on whether they gave up smoking.

Results

Patients in the death group had a longer smoking time, lower prevalence of quitting smoking, later onset of COPD symptoms, older age at quitting smoking, lower forced expiratory volume in one second (FEV₁) % predicted, and lower ratio of FEV₁/forced vital capacity. Age, age at quitting smoking, and FEV₁% predicted were independently associated with mortality from COPD. Compared to the continuing-smoking group, the quitting-smoking group had a lower mortality rate, longer course of COPD, earlier onset of COPD symptoms, and lower residual volume percent predicted. During the 5-year follow-up, 113 deaths were recorded (quitting-smoking group: n=92; 40 deaths; continuing-smoking group: n=112; 73 deaths). The mortality risk remained significantly higher in the continuing-smoking group than the quitting-smoking group (log-rank test, 13.59; P=0.0002).

Conclusion

Smoking time may be related to the mortality rate from COPD. Smoking cessation has the greatest capacity to influence the natural history of COPD.

Effects of emissions from sugar cane burning on the trachea and lungs of Wistar rats

Objective:

To evaluate the effects of exposure to emissions from sugar cane burning on inflammatory mechanisms in tissues of the trachea and lung parenchyma in Wistar rats after different periods of exposure.

Methods:

This was an experimental open randomized study. The animals were divided into four groups: a control group (CG) underwent standard laboratory conditions, and three experimental groups were exposed to emissions from sugar cane burning over different periods of time, in days-1 (EG1), 7 (EG7), and 21 (EG21). After euthanasia with 200 mg/kg of ketamine/xylazine, fragments of trachea and lung were collected and fixed in 10% formalin. Histological analyses were performed with H&E and picrosirius red staining.

Results:

No inflammatory infiltrates were found in the tissues of CG rats. The histological examination of tissues of the trachea and lung parenchyma revealed that the inflammatory process was significantly more intense in EG7 than in the CG (p < 0.05 and p < 0.01, respectively). In comparison with the CG and EG1, angiogenesis in the lung parenchyma and collagen deposition in tracheal tissues were significantly greater only in EG21 (p < 0.001 and p < 0.01, respectively).

Conclusions:

In this sample, emissions from sugar cane burning induced acute focal and diffuse inflammation in the lamina propria of tracheal tissues, with no loss of ciliated epithelial tissue. In the lung parenchyma of the animals in the experimental groups, there was interstitial and alveolar edema, together with polymorphonuclear cell infiltrates.

Is Chronic Obstructive Pulmonary Disease Caused by Wood Smoke a Different Phenotype or a Different Entity?

Around 40% of the world's population continue using solid fuel, including wood, for cooking or heating their homes. Chronic exposure to wood smoke is a risk factor for developing chronic obstructive pulmonary disease (COPD). In some regions of the world, this can be a more important cause of COPD than exposure to tobacco smoke from cigarettes. Significant differences between COPD associated with wood smoke (W-COPD) and that caused by smoking (S-COPD) have led some authors to suggest that W-COPD should be considered a new COPD phenotype. We present a review of the differences between W-COPD and S-COPD. On the premise that wood smoke and tobacco smoke are not the same and the physiopathological mechanisms they induce may differ, we have analyzed whether W-COPD can be considered as another COPD phenotype or a distinct nosological entity.

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.