Exposure to particulate matter (PM) is generally associated with elevated risk of cardiovascular morbidity and mortality. Elderly and obese subjects may be particularly susceptible, although short-term effects are poorly described. Sixty healthy subjects (25 males, 35 females, age 55 to 83 years, body mass index > 25 kg/m2) were included in a cross-over study with 5 hours of exposure to particle- or sham-filtered air from a busy street using an exposure-chamber. The sham- versus particle-filtered air had average particle number concentrations of ~23.000 versus ~1800/cm3 and PM2.5 levels of 24 versus 3μg/m3, respectively. The PM contained similar fractions of elemental and black carbon (~20-25%) in both exposure scenarios. Reactive hyperemia and nitroglycerin-induced vasodilation in finger arteries and heart rate variability (HRV) measured within 1 h after exposure were primary outcomes. Potential explanatory mechanistic variables included markers of oxidative stress (ascorbate/dehydroascorbate, nitric oxide-production cofactor tetrahydrobiopterin and its oxidation product dihydrobiopterin) and inflammation markers (C-reactive protein and leukocyte differential counts). Nitroglycerin-induced vasodilation was reduced by 12% [95% confidence interval: −22%; −1.0%] following PM exposure, whereas hyperemia-induced vasodilation was reduced by 5% [95% confidence interval: −11.6%; 1.6%]. Moreover, HRV measurements showed that the high and low frequency domains were significantly decreased and increased, respectively. Redox and inflammatory status did not change significantly based on the above measures. This study indicates that exposure to real-life levels of PM from urban street air impairs the vasomotor function and HRV in overweight middle-aged and elderly adults, although this could not be explained by changes in inflammation, oxidative stress or nitric oxide-cofactors.

中文翻译：

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在超重和老年人中，控制性暴露于城市街道空气中的颗粒物与血管舒张和心率变异性降低有关。

接触颗粒物（PM）通常会增加心血管疾病的发病率和死亡率。尽管对短期效应的描述很少，但老年人和肥胖的受试者可能特别容易受到影响。60名健康受试者（男25名，女35名，年龄55至83岁，体重指数> 25 kg / m2）纳入交叉研究，暴露于繁忙街道上经过颗粒或深水过滤的空气5个小时使用曝光室。假空气和颗粒过滤空气的平均颗粒数浓度分别为〜23.000和〜1800 / cm3，以及PM2.5水平分别为24和3μg/ m3。在两种暴露情况下，PM都包含相似比例的元素碳和黑碳（约20-25％）。主要的结果是暴露后1小时内测得的手指动脉反应性充血和硝酸甘油诱导的血管舒张以及心率变异性（HRV）。潜在的解释性机械变量包括氧化应激的标志物（抗坏血酸/脱氢抗坏血酸，一氧化氮生成辅助因子四氢生物蝶呤及其氧化产物二氢生物蝶呤）和炎症标志物（C反应蛋白和白细胞差异计数）。硝酸甘油诱导的血管舒张减少了12％[95％置信区间：-22％；PM暴露后为−1.0％]，而充血引起的血管舒张减少了5％[95％置信区间：-11.6％；1.6％]。此外，HRV测量结果表明，高频域和低频域分别显着减少和增加。根据上述方法，氧化还原和炎症状态没有明显改变。这项研究表明，城市街道空气暴露于现实生活中的PM会损害超重中老年人的血管舒缩功能和HRV，尽管这不能用炎症，氧化应激或一氧化氮-辅因子的变化来解释。