BNP levels in patients with long-term exposure to biomass fuel and its relation to right ventricular function

A hypothesis: Potential contributions of metals to the pathogenesis of pulmonary artery hypertension

Pulmonary artery hypertension (PAH) is characterized by vasoconstriction and vascular remodeling resulting in both increased pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP). The chronic and high-pressure stress experienced by endothelial cells can give rise to inflammation, oxidative stress, and infiltration by immune cells. However, there is no clearly defined mechanism for PAH and available treatment options only provide limited symptomatic relief. Due to the far-reaching effects of metal exposures, the interaction between metals and the pulmonary vasculature is of particular interest. This review will briefly introduce the pathophysiology of PAH and then focus on the potential roles of metals, including essential and non-essential metals in the pathogenic process in the pulmonary arteries and right heart, which may be linked to PAH. Based on available data from human studies of occupational or environmental metal exposure, including lead, antimony, iron, and copper, the hypothesis of metals contributing to the pathogenesis of PAH is proposed as potential risk factors and underlying mechanisms for PAH. We propose that metals may initiate or exacerbate the pathogenesis of PAH, by providing potential mechanism by which metals interact with hypoxia-inducible factor and tumor suppressor p53 to modulate their downstream cellular proliferation pathways. These need further investigation. Additionally, we present future research directions on roles of metals in PAH.

Metallomics in pulmonary arterial hypertension patients

Pulmonary arterial hypertension (PAH) prevalence is increasing worldwide, and the prognosis is poor with 5-year survival < 50% in high risk patients. The relationship between metal exposure/essential metal dyshomeostasis and PAH/right ventricular dysfunction is less investigated. The aim of this study is to investigate vegetable consumptions and metal levels between PAH patients and controls. This was a prospective, single center pilot study. Questionnaires were completed by all study subjects (20 PAH patients and 10 healthy controls) on smoking, metal exposure risks, metal supplements, and vegetable consumptions. Blood and urine samples were collected to measure 25 metal levels in blood, plasma, and urine using an X Series II quadrupole inductively coupled plasma mass spectrometry. Statistical analysis was conducted using SAS 9.5 and results with p value < 0.05 were considered significant. Vegetables consumptions (broccoli risk ratio [RR] = 0.4, CI = (0.2, 0.9)], cabbage [RR = 0.2, CI = (0.1, 0.8)], and brussel sprouts [RR = 0.2, CI = (0.1, 0.5)]) are associated with less risks of PAH. In the plasma samples, silver (p < 0.001), and copper (p = 0.002) levels were significantly higher in PAH patients. There was significant positive correlation between cardiac output and cardiac index with plasma levels of silver (r = 0.665, p = 0.001 and r = 0.678 p = 0.001), respectively. There was significant correlation between mixed venous saturation, 6-min walk distance, and last BNP with plasma levels of chromium (r = -0.520, p = 0.022; r = -0.55, p = 0.014; r = 0.463, p = 0.039), respectively. In conclusion, there are significant differences between PAH and control groups in terms of vegetable consumptions and metal concentrations. Silver and chromium levels are correlated with clinical indicators of PAH severities.

All-Cause Mortality Risk Associated With Solid Fuel Use Among Chinese Elderly People: A National Retrospective Longitudinal Study

Background: The adverse health effects of air pollutants are widely reported, and the elderly are susceptible to toxic environments. This study aimed to evaluate the association between use of solid fuels for cooking and mortality among the elderly. Methods: A total of 5,732 and 3,869 participants from the Chinese Longitudinal Healthy Longevity Survey were enrolled in two (2014 and 2018) and three surveys (2011, 2014, and 2018) of survey. Cooking fuel was divided into clean and solid fuel. Cox proportional hazards models were used to estimate the mortality hazard ratio (HR). Subgroup analyses were performed to assess the potential interaction effect. Results: Among the participants in the 2011-2018 survey, 53% reported using solid fuel. Such group was associated with a 9% increase in mortality risk relative to clean fuel users (HR = 1.09, 95% CI = 1.01-1.18). Among participants in the 2014-2018 survey, 339 reported a switch from solid to clean fuels and they were not at increased mortality risk relative to the 488 people that reported a stable use of clean fuels (HR = 1.14, 95% CI = 0.99-1.31) although the estimated HR was similar to the one for stable solid fuel users (HR = 1.19, 95%CI = 1.04-1.36 n = 509). Interaction and stratified analyses showed that solid fuel use had an impact on mortality in participants who were non-current smokers, had low dietary diversity scores, and were living in areas with high PM2.5 concentrations (>50 μg/m3) and city population below 8 million (P for interaction < 0.05). The association was robust in the three sensitivity analyses. Conclusion: The finding showed a clear association between solid fuel use and mortality among older Chinese, and an even stronger association between risk of mortality and solid fuel use among individuals exposed to high levels of PM2.5.

Prenatal Particulate Matter (PM) Exposure and Natriuretic Peptides in Newborns from Mexico City

(1) Background: The aim of this study was to assess associations between particulate matter (PM) exposure and natriuretic peptide concentrations in cord blood from newborns. (2) Methods: we conducted a cross-sectional study in Mexico City with 101 pregnant women from CIMIGEN Hospital. Atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) were measured in plasma from cord blood in 51 newborns by ELISA. We estimated PM exposure (PM2.5 and PM10) at first, second and third trimester of pregnancy. (3) Results: The median and interquartile range for ANP, BNP and CNP plasma concentrations were 66.71 (46.92-80.23), 98.23 (73.64-112.30) and 1129.11 (944.10-1452.02) pg/mL, respectively. PM2.5 and PM10 levels for the whole pregnancy period were 22.2 µg/m³ and 41.63 µg/m³, respectively. Employing multivariable linear regression models adjusted for maternal age, newborn sex, smoking before pregnancy, maternal occupation and newborns' length and height, we observed a 2.47 pg/mL (95%CI: -4.67, -0.27) decrease in BNP associated with PM2.5 exposure during second trimester. Adjusted for the same set of confounders, third trimester PM10 exposure was inversely associated with ANP concentrations (beta estimate: -0.90; 95% CI: -1.80, -0.03). Neither PM10 nor PM2.5 were associated with CNP at any trimester of pregnancy. (4) Conclusions: Prenatal exposure to particulate matter was associated with ANP and BNP decrease in newborns.

Pulmonary exposure to peat smoke extracts in rats decreases expiratory time and increases left heart end systolic volume

Exposure to wildland fire-related particulate matter (PM) causes adverse health outcomes. However, the impacts of specific biomass sources remain unclear. The purpose of this study was to investigate cardiopulmonary responses in rats following exposure to PM extracts collected from peat fire smoke. We hypothesized that peat smoke PM would dose-dependently alter cardiopulmonary function. Male Sprague-Dawley rats (n = 8/group) were exposed to 35 µg (Lo PM) or 350 µg (Hi PM) of peat smoke PM extracts suspended in saline, or saline alone (Vehicle) via oropharyngeal aspiration (OA). Ventilatory expiration times, measured in whole-body plethysmographs immediately after OA, were the lowest in Hi PM exposed subjects at 6 min into recovery (p = .01 vs. Lo PM, p = .08 vs. Vehicle) and resolved shortly afterwards. The next day, we evaluated cardiovascular function in the same subjects via cardiac ultrasound under isoflurane anesthesia. Compared to Vehicle, Hi PM had 45% higher end systolic volume (p = .03) and 17% higher pulmonary artery blood flow acceleration/ejection time ratios, and both endpoints expressed significant increasing linear trends by dose (p = .01 and .02, respectively). In addition, linear trend analyses across doses detected an increase for end diastolic volume and decreases for ejection fraction and fractional shortening. These data suggest that exposure to peat smoke constituents modulates regulation of ventricular ejection and filling volumes, which could be related to altered blood flow in the pulmonary circulation. Moreover, early pulmonary responses to peat smoke PM point to irritant/autonomic mechanisms as potential drivers of later cardiovascular responses.

Review of the health effects of wildland fire smoke on wildland firefighters and the public

Each year, the general public and wildland firefighters in the US are exposed to smoke from wildland fires. As part of an effort to characterize health risks of breathing this smoke, a review of the literature was conducted using five major databases, including PubMed and MEDLINE Web of Knowledge, to identify smoke components that present the highest hazard potential, the mechanisms of toxicity, review epidemiological studies for health effects and identify the current gap in knowledge on the health impacts of wildland fire smoke exposure. Respiratory events measured in time series studies as incidences of disease-caused mortality, hospital admissions, emergency room visits and symptoms in asthma and chronic obstructive pulmonary disease patients are the health effects that are most commonly associated with community level exposure to wildland fire smoke. A few recent studies have also determined associations between acute wildland fire smoke exposure and cardiovascular health end-points. These cardiopulmonary effects were mostly observed in association with ambient air concentrations of fine particulate matter (PM2.5). However, research on the health effects of this mixture is currently limited. The health effects of acute exposures beyond susceptible populations and the effects of chronic exposures experienced by the wildland firefighter are largely unknown. Longitudinal studies of wildland firefighters during and/or after the firefighting career could help elucidate some of the unknown health impacts of cumulative exposure to wildland fire smoke, establish occupational exposure limits and help determine the types of exposure controls that may be applicable to the occupation.

Exposure to occupational air pollution and cardiac function in workers of the Esfahan Steel Industry, Iran

Air pollution is recognized as an important risk factor for cardiovascular disease. We investigated association of exposure to occupational air pollution and cardiac function in the workers of the steel industry. Fifty male workers of the agglomeration and coke-making parts of the Esfahan Steel Company were randomly selected (n = 50). Workers in the administrative parts were studied as controls (n = 50). Those with known history of hypertension, dyslipidemia, or diabetes, and active smokers were not included. Data of age, body mass index, employment duration, blood pressure, fasting blood sugar, and lipid profile were gathered. Echocardiography was performed to evaluate cardiac function. Left ventricular ejection fraction was lower in workers of the agglomeration/coke-making parts than in controls (mean difference = 5 to 5.5 %, P < 0.001). Mild right ventricular dilatation and grade I pulmonary hypertension were present in three (12 %) workers of the coke-making part, but none of the controls (P = 0.010). According to these results, occupational air pollution exposure in workers of the steel industry is associated with left heart systolic dysfunction. Possible right heart insults due to air pollution exposure warrant further investigations.

Lack of association between chronic exposure to biomass fuel smoke and markers of right ventricular pressure overload at high altitude

BACKGROUND

Chronic exposure to biomass fuel smoke has been implicated in the development of pulmonary hypertension and right ventricular pressure/volume overload through activation of inflammation, increase in vascular resistance, and endothelial dysfunction. We sought to compare N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and echocardiography-derived pulmonary artery systolic pressure (PASP) levels in a high-altitude population-based study in Peru with and without chronic exposure to biomass fuel smoke.

METHODS

NT-pro-BNP levels were measured in 519 adults (275 with and 244 without chronic exposure to biomass fuel smoke). Participants answered sociodemographics and clinical history questionnaires, underwent a clinical examination and blood testing for cardiopulmonary biomarkers. PASP was measured in a subgroup of 153 (31%) subjects.

RESULTS

The study group consisted of 280 men (54%) and 239 women (46%). Average age was 56 years and average body mass index was 27 kg/m(2). In multivariable analysis, there was no association between chronic exposure to biomass fuel smoke and NT-pro-BNP (P = .31) or PASP (P = .31). In the subgroup in which both NT-pro-BNP levels and PASP were measured, there was strong evidence of an association between these two variables (ρ = 0.24, 95% CI 0.09-0.39; P = .003). We found that age, high sensitivity C-reactive protein, being male, and systolic blood pressure were positively associated with NT-pro-BNP levels whereas body mass index, low-density/high-density lipoprotein ratio, and Homeostasis Model of Assessment-Insulin Resistance were negatively associated (all P ≤ .02).

CONCLUSIONS

In this population-based study in a high-altitude setting, neither NT-pro-BNP levels nor echocardiography-derived PASP were associated with chronic exposure to biomass fuel smoke.

Solid fuel use is a major risk factor for acute coronary syndromes among rural women: a matched case control study

OBJECTIVES

Almost half of the world's population uses solid fuel for cooking, exposing women to high levels of particulate pollution in indoor air. The risk of acute coronary syndrome (ACS) was assessed among rural women, according to their use of solid fuel.

STUDY DESIGN

Matched case control study.

METHODS

Data were collected at a public tertiary care hospital in a rural district of Pakistan. Seventy-three women with ACS were compared with controls, individually matched for sex and age (± 5 years), who were admitted to hospital for other reasons. Fuels used for cooking and exposures to potentially confounding variables were ascertained through a questionnaire administered at interview and measurement of height and weight. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (95% CIs).

RESULTS

After adjustment for potential confounding factors, current use of solid fuel was strongly associated with ACS (OR 4.8, 95% CI: 1.5-14.8), and risk was lowest in women who had last used solid fuel more than 15 years earlier. The population attributable fraction for ACS in relation to current use of solid fuel was 49.0% (95% CI: 41.3%-57.4%).

CONCLUSIONS

These findings support the hypothesis that indoor air pollution from use of solid fuel is an important cause of ACS. Our study demonstrates the feasibility of case-control studies in rural populations of women to address this question, and is an encouragement to larger and statistically more powerful investigations.

Diesel exhaust induced pulmonary and cardiovascular impairment: the role of hypertension intervention

Exposure to diesel exhaust (DE) and associated gases is linked to cardiovascular impairments; however, the susceptibility of hypertensive individuals is poorly understood. The objectives of this study were (1) to determine cardiopulmonary effects of gas-phase versus whole-DE and (2) to examine the contribution of systemic hypertension in pulmonary and cardiovascular effects. Male Wistar Kyoto (WKY) rats were treated with hydralazine to reduce blood pressure (BP) or l-NAME to increase BP. Spontaneously hypertensive (SH) rats were treated with hydralazine to reduce BP. Control and drug-pretreated rats were exposed to air, particle-filtered exhaust (gas), or whole DE (1500μg/m(3)), 4h/day for 2days or 5days/week for 4weeks. Acute and 4-week gas and DE exposures increased neutrophils and γ-glutamyl transferase (γ-GT) activity in lavage fluid of WKY and SH rats. DE (4weeks) caused pulmonary albumin leakage and inflammation in SH rats. Two-day DE increased serum fatty acid binding protein-3 (FABP-3) in WKY. Marked increases occurred in aortic mRNA after 4-week DE in SH (eNOS, TF, tPA, TNF-α, MMP-2, RAGE, and HMGB-1). Hydralazine decreased BP in SH while l-NAME tended to increase BP in WKY; however, neither changed inflammation nor BALF γ-GT. DE-induced and baseline BALF albumin leakage was reduced by hydralazine in SH rats and increased by l-NAME in WKY rats. Hydralazine pretreatment reversed DE-induced TF, tPA, TNF-α, and MMP-2 expression but not eNOS, RAGE, and HMGB-1. ET-1 was decreased by HYD. In conclusion, antihypertensive drug treatment reduces gas and DE-induced pulmonary protein leakage and expression of vascular atherogenic markers.

THE INDOOR-OUTDOOR AIR-POLLUTION CONTINUUM AND THE BURDEN OF CARDIOVASCULAR DISEASE: AN OPPORTUNITY FOR IMPROVING GLOBAL HEALTH

Current understanding of the association between household air-pollution (HAP) and cardiovascular disease is primarily derived from outdoor air-pollution studies. The lack of accurate information on the contribution of HAP to cardiovascular events has prevented inclusion of such data in global burden of disease estimates with consequences in terms of health care allocation and national/international priorities. Understanding the health risks, exposure characterization, epidemiology and economics of the association between HAP and cardiovascular disease represents a pivotal unmet public health need. Interventions to reduce exposure to air-pollution in general, and HAP in particular are likely to yield large benefits and may represent a cost-effective and economically sustainable solution for many parts of the world. A multi-disciplinary effort that provides economically feasible technologic solutions in conjunction with experts that can assess the health, economic impact and sustainability are urgently required to tackle this problem.