A community study of the effect of particulate matter on blood measures of inflammation and thrombosis in an elderly population

BACKGROUND: The mechanism behind the triggering effect of fine particulate matter (PM) air pollution on cardiovascular events remains elusive. We postulated that elevated levels of PM would be associated with increased blood levels of inflammatory and thrombotic markers in elderly individuals. We also hypothesized that elevated PM would increase levels of cytokines in individuals with heart disease. METHODS: We measured these blood markers in 47 elderly individuals with (23) and without (16 COPD and 8 healthy) cardiovascular disease (CVD) on 2 or 3 mornings over a 5 or 10-day period between February 2000 and March 2002. Blood measures were paired with residence level outdoor PM measured by nephelometry. Analyses determined the within-individual effect of 24-hour averaged outdoor PM on blood measures. RESULTS: Analyses found no statistically significant effect of a same day 10 ug/m(3 )increase in fine PM on log transformed levels of CRP 1.21 fold-rise [95% CI: 0.86, 1.70], fibrinogen 1.02 fold-rise [95% CI: 0.98, 1.06], or D-dimer 1.02 fold-rise [95% CI: 0.88, 1.17] in individuals with CVD. One-day lagged analyses in the CVD subgroup found similar null results. These same models found no change in these blood markers at the same-day or 1-day lag in the group without CVD. In 21 individuals with CVD, a 10 μg/m(3 )increase in same-day PM was associated with a 1.3 fold-rise [95% CI: 1.1, 1.7] in the level of monocyte chemoattractant protein-1. CONCLUSION: We did not find consistent effects of low ambient levels of PM on blood measures of inflammation or thrombosis in elderly individuals

Pulmonary Effects of Indoor- and Outdoor-Generated Particles in Children with Asthma

Most particulate matter (PM) health effects studies use outdoor (ambient) PM as a surrogate for personal exposure. However, people spend most of their time indoors exposed to a combination of indoor-generated particles and ambient particles that have infiltrated. Thus, it is important to investigate the differential health effects of indoor- and ambient-generated particles. We combined our recently adapted recursive model and a predictive model for estimating infiltration efficiency to separate personal exposure (E) to PM(2.5) (PM with aerodynamic diameter ≤2.5 μm) into its indoor-generated (E(ig)) and ambient-generated (E(ag)) components for 19 children with asthma. We then compared E(ig) and E(ag) to changes in exhaled nitric oxide (eNO), a marker of airway inflammation. Based on the recursive model with a sample size of eight children, E(ag) was marginally associated with increases in eNO [5.6 ppb per 10-μg/m(3) increase in PM(2.5); 95% confidence interval (CI), −0.6 to 11.9; p = 0.08]. E(ig) was not associated with eNO (−0.19 ppb change per 10μg/m(3)). Our predictive model allowed us to estimate E(ag) and E(ig) for all 19 children. For those combined estimates, only E(ag) was significantly associated with an increase in eNO (E(ag): 5.0 ppb per 10-μg/m(3) increase in PM(2.5;) 95% CI, 0.3 to 9.7; p = 0.04; E(ig): 3.3 ppb per 10-μg/m(3) increase in PM(2.5); 95% CI, −1.1 to 7.7; p = 0.15). Effects were seen only in children who were not using corticosteroid therapy. We conclude that the ambient-generated component of PM(2.5) exposure is consistently associated with increases in eNO and the indoor-generated component is less strongly associated with eNO

Diesel Exhaust Inhalation Elicits Acute Vasoconstriction in Vivo

BACKGROUND: Traffic-related air pollution is consistently associated with cardiovascular morbidity and mortality. Recent human and animal studies suggest that exposure to air pollutants affects vascular function. Diesel exhaust (DE) is a major source of traffic-related air pollution. OBJECTIVES: Our goal was to study the effects of short-term exposure to DE on vascular reactivity and on mediators of vascular tone. METHODS: In a double-blind, crossover, controlled exposure study, 27 adult volunteers (10 healthy and 17 with metabolic syndrome) were exposed in randomized order to filtered air (FA) and each of two levels of diluted DE (100 or 200 μg/m3 of fine particulate matter) in 2-hr sessions. Before and after each exposure, we assessed the brachial artery diameter (BAd) by B-mode ultrasound and collected blood samples for endothelin-1 (ET-1) and catecholamines. Postexposure we also assessed endothelium-dependent flow-mediated dilation (FMD). RESULTS: Compared with FA, DE at 200 μg/m3 elicited a decrease in BAd (0.11 mm; 95% confidence interval, 0.02–0.18), and the effect appeared linearly dose related with a smaller effect at 100 μg/m3. Plasma levels of ET-1 increased after 200 μg/m3 DE but not after FA (p = 0.01). There was no consistent impact of DE on plasma catecholamines or FMD. CONCLUSIONS: These results demonstrate that short-term exposure to DE is associated with acute endothelial response and vasoconstriction of a conductance artery. Elucidation of the signaling pathways controlling vascular tone that underlie this observation requires further study

Flow mediated dilation of the brachial artery: an investigation of methods requiring further standardization

BACKGROUND: In order to establish a consistent method for brachial artery reactivity assessment, we analyzed commonly used approaches to the test and their effects on the magnitude and time-course of flow mediated dilation (FMD), and on test variability and repeatability. As a popular and noninvasive assessment of endothelial function, several different approaches have been employed to measure brachial artery reactivity with B-mode ultrasound. Despite some efforts, there remains a lack of defined normal values and large variability in measurement technique. METHODS: Twenty-six healthy volunteers underwent repeated brachial artery diameter measurements by B-mode ultrasound. Following baseline diameter recordings we assessed endothelium-dependent flow mediated dilation by inflating a blood pressure cuff either on the upper arm (proximal) or on the forearm (distal). RESULTS: Thirty-seven measures were performed using proximal occlusion and 25 with distal occlusion. Following proximal occlusion relative to distal occlusion, FMD was larger (16.2 ± 1.2% vs. 7.3 ± 0.9%, p < 0.0001) and elongated (107.2 s vs. 67.8 s, p = 0.0001). Measurement of the test repeatability showed that differences between the repeated measures were greater on average when the measurements were done using the proximal method as compared to the distal method (2.4%; 95% CI 0.5–4.3; p = 0.013). CONCLUSION: These findings suggest that forearm compression holds statistical advantages over upper arm compression. Added to documented physiological and practical reasons, we propose that future studies should use forearm compression in the assessment of endothelial function

Pulmonary Effects of Indoor- and Outdoor-Generated Particles in Children with Asthma-0

<p><b>Copyright information:</b></p><p>Taken from "Pulmonary Effects of Indoor- and Outdoor-Generated Particles in Children with Asthma"</p><p>Environmental Health Perspectives 2005;113(4):499-503.</p><p>Published online 10 Jan 2005</p><p>PMCID:PMC1278493.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p