Brook Robert D, Bard Robert L, Morishita Masako, Dvonch J Timothy, Wang Lu, Yang Hui-Yu, Spino Catherine, Mukherjee Bhramar, Kaplan Mariana J, Yalavarthi Srilakshmi, Oral Elif A, Ajluni Nevin, Sun Qinghua, Brook Jeffrey R, Harkema Jack, Rajagopalan Sanjay
Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Environ Health Perspect. 2014 Jun;122(6):624-30. doi: 10.1289/ehp.1306595. Epub 2014 Mar 11.
Fine particulate matter (PM) air pollution is associated with numerous adverse health effects, including increased blood pressure (BP) and vascular dysfunction. Coarse PM substantially contributes to global air pollution, yet differs in characteristics from fine particles and is currently not regulated. However, the cardiovascular (CV) impacts of coarse PM exposure remain largely unknown.
Our goal was to elucidate whether coarse PM, like fine PM, is itself capable of eliciting adverse CV responses.
We performed a randomized double-blind crossover study in which 32 healthy adults (25.9 ± 6.6 years of age) were exposed to concentrated ambient coarse particles (CAP; 76.2 ± 51.5 μg/m(3)) in a rural location and filtered air (FA) for 2 hr. We measured CV outcomes during, immediately after, and 2 hr postexposures.
Both systolic (mean difference = 0.32 mmHg; 95% CI: 0.05, 0.58; p = 0.021) and diastolic BP (0.27 mmHg; 95% CI: 0.003, 0.53; p = 0.05) linearly increased per 10 min of exposure during the inhalation of coarse CAP when compared with changes during FA exposure. Heart rate was on average higher (4.1 bpm; 95% CI: 3.06, 5.12; p < 0.0001) and the ratio of low-to-high frequency heart rate variability increased (0.24; 95% CI: 0.07, 0.41; p = 0.007) during coarse particle versus FA exposure. Other outcomes (brachial flow-mediated dilatation, microvascular reactive hyperemia index, aortic hemodynamics, pulse wave velocity) were not differentially altered by the exposures.
Inhalation of coarse PM from a rural location is associated with a rapid elevation in BP and heart rate during exposure, likely due to the triggering of autonomic imbalance. These findings add mechanistic evidence supporting the biological plausibility that coarse particles could contribute to the triggering of acute CV events.
细颗粒物（PM）空气污染与众多不良健康影响相关，包括血压（BP）升高和血管功能障碍。粗颗粒物对全球空气污染有很大贡献，但其特性与细颗粒物不同，目前不受监管。然而，暴露于粗颗粒物对心血管（CV）的影响在很大程度上仍不清楚。
我们的目标是阐明粗颗粒物是否像细颗粒物一样，本身能够引发不良的心血管反应。
我们进行了一项随机双盲交叉研究，32名健康成年人（年龄25.9±6.6岁）在农村地区暴露于浓缩环境粗颗粒物（CAP；76.2±51.5μg/m³）和过滤空气（FA）中2小时。我们在暴露期间、暴露后立即以及暴露后2小时测量心血管结局。
与暴露于过滤空气期间的变化相比，吸入粗CAP期间，每暴露10分钟，收缩压（平均差异=0.32mmHg；95%CI：0.05，0.58；p=0.021）和舒张压（0.27mmHg；95%CI：0.003，0.53；p=0.05）呈线性升高。与暴露于过滤空气相比，暴露于粗颗粒物期间心率平均更高（4.1次/分钟；95%CI：3.06，5.12；p<0.0001），低频与高频心率变异性比值增加（0.24；95%CI：0.07，0.41；p=0.007）。其他结局（肱动脉血流介导的扩张、微血管反应性充血指数、主动脉血流动力学、脉搏波速度）未因暴露而有差异改变。
吸入农村地区的粗颗粒物与暴露期间血压和心率的快速升高有关，这可能是由于自主神经失衡的触发。这些发现增加了机制证据，支持粗颗粒物可能导致急性心血管事件触发的生物学合理性。
