Background:

Vascular dysfunction is a biological pathway whereby particulate matter (PM) exerts deleterious cardiovascular effects. The effects of ambient PM on vascular function in prediabetic individuals are unclear.

Methods:

A panel study recruited 112 Beijing residents with and without prediabetes. Multiple vascular function indices were measured up to 7 times. The associations between vascular function indices and short-term exposure to ambient PM, including fine particulate matter (PM2.5), ultrafine particles, accumulation mode particles, and black carbon, and the modification of these associations by glucose metabolic status were examined using linear mixed-effects models.

Results:

Increases in brachial artery pulse pressure, central aortic pulse pressure, and ejection duration, and decreases in subendocardial viability ratio and reactive hyperemia index were significantly associated with at least one PM pollutant in all participants, indicating increased vascular dysfunction. For example, for an interquartile range increment in 5-day moving average ultrafine particles, brachial artery pulse pressure, and central aortic pulse pressure increased 5.4% (0.8%–10.4%) and 6.2% (1.2%–11.5%), respectively. Additionally, PM-associated changes in vascular function differed according to glucose metabolic status. Among participants with high fasting blood glucose levels (≥6.1 mmol/L), PM exposure was significantly associated with increased brachial artery systolic blood pressure, central aortic systolic blood pressure, brachial artery pulse pressure, central aortic pulse pressure, and augmentation pressure normalized to a heart rate of 75 bpm and decreased subendocardial viability ratio and reactive hyperemia index. Weaker or null associations were observed in the low-fasting blood glucose group.

Conclusions:

Glucose metabolic disorders may exacerbate vascular dysfunction associated with short-term ambient PM exposure.

在中国近50%的成年人的血糖代谢紊乱，其中10.9%的成年人罹患糖尿病，35.7%的成年人处于糖尿病前期状态。糖尿病和糖尿病前期人群通常面临着多种心血管疾病风险因素的威胁，包括血糖代谢紊乱、血脂代谢紊乱、高血压、肥胖、运动不足等。已有研究表明，这类人群可能对大气颗粒物的不良心血管效应更加易感。血管功能失调是大气颗粒物引发心血管疾病的重要机制之一，但目前对于血糖代谢紊乱人群中大气颗粒物引发的血管功能损伤的认识还十分有限。

北京大学环境科学与工程学院朱彤教授课题组于2013-2015年在北京大学校医院开展前瞻性定组研究SCOPE (A prospective Study COmparing the cardiometabolic and respiratory effects of air Pollution Exposure on healthy and prediabetic individuals)，同时对31名糖尿病前期受试者和81名血糖正常的对照受试者进行跟踪随访。通过在北大校园固定站点连续观测的大气颗粒物浓度数据评估受试者的大气污染暴露水平，测量多项血管功能指标：包括外周血压BP、中心血压CBP、增强压AP、增强指数Aix、心内膜下心肌活力率SEVR等 (Sphygmocor, AtCor Medical, Sydney, Australia) 及反应性充血指数RHI（EndoPAT,Itamar Medical, Israel）以综合评价受试者的血管功能，采用线性混合效应模型探究了大气颗粒物暴露与血管功能的关联性及血糖代谢状态的修饰作用。

该研究表明，大气颗粒物暴露与血管功能失调相关，具体表现为细颗粒物（PM2.5）、粒径小于100纳米的超细颗粒物（UFP）、粒径在100到560纳米的积聚模态颗粒物（AMP）、黑碳（BC）暴露后，受试者血管弹性降低（脉压升高、射血时间增长、心内膜下心肌的活力率降低），内皮功能失调（反应性充血指数降低）。该研究进一步在血糖水平较高的人群中观察到与大气颗粒物相关的血管功能损伤效应比血糖水平较低的人群更显著，例如，在UFP和AMP暴露后，血糖水平较高的人群中收缩压和脉压显著升高，血糖水平较低的人群则无显著变化。

这一研究结果提示血糖代谢紊乱可能加剧大气颗粒物对血管功能的损伤，血糖代谢紊乱人群可能面临更高的由大气颗粒物引发的心血管疾病风险，因此有必要开展更深入的研究来阐明易感性产生的机制，同时采取有效的空气污染控制措施和适当的临床干预手段来保护公众健康。

该研究近日以“Glucose metabolic disorders enhance vascular dysfunction triggered by particulate air pollution: A panel study”为题发表于美国心脏协会心血管著名期刊Hypertension上。北京大学环境科学与工程学院博士后陈悟、韩逸群（现为英国帝国理工学院博士后）为该论文共同第一作者，朱彤教授为通讯作者。该项研究获得国家自然科学基金（21190051、41421064、91844000）和科技部973项目（2015CB553401）的支持，并获得北京大学生物医学伦理委员会的批准（IRB00001052-13024）。

论文信息及链接：Chen W, Han Y, Wang Y, et al. Glucose metabolic disorders enhance vascular dysfunction triggered by particulate air pollution: A panel study. Hypertension, 2022;79(5):1079-1090.

https://doi.org/10.1161/HYPERTENSIONAHA.121.18889

（来源：朱彤课题组）