Mechanisms of Inhaled Fine Particulate Air Pollution-Induced Arterial Blood Pressure Changes

• Published in: Environmental health perspectives 2009-03, Vol.117 (3), p.361-366
• Main Authors: Bartoli, Carlo R., Wellenius, Gregory A., Diaz, Edgar A., Lawrence, Joy, Coull, Brent A., Akiyama, Ichiro, Lee, Lani M., Okabe, Kazunori, Verrier, Richard L., Godleski, John J.
• Format: Article
• Language: English
• Subjects: Air pollution; Alterations; Animals; Arteries; Baroreceptors; Baroreflex - drug effects; Baroreflexes; Black carbon; Blocking; Blood pressure; Blood Pressure - drug effects; Copyrights; Cross-Over Studies; Crossovers; Devices; Diastolic blood pressure; Dogs; Environmental health; Epidemiology; Exposure; Health; Health aspects; Heart rate; Heart Rate - drug effects; Hemodynamics; Hypertension; Inhalation; Inhalation Exposure - adverse effects; Linear Models; Mathematical models; Particle mass; Particulate matter; Particulate Matter - administration & dosage; Particulate Matter - toxicity; Reflexes; Risk factors; Telemetry
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.11573

Background: Epidemiologic studies suggest a positive association between fine particulate matter and arterial blood pressure, but the results have been inconsistent. Objectives: We investigated the effect of ambient particles on systemic hemodynamics during a 5-hr exposure to concentrated ambient air particles (CAPs) or filtered air (FA) in conscious canines. Methods: Thirteen dogs were repeatedly exposed via permanent tracheostomy to CAPs (358.1 ± 306.7 μg/m³, mean ± SD) or FA in a crossover protocol (55 CAPs days, 63 FA days). Femoral artery blood pressure was monitored continuously via implanted telemetry devices. We measured baroreceptor reflex sensitivity before and after exposure in a subset of these experiments (n = 10 dogs, 19 CAPs days, 20 FA days). In additional experiments, we administered α-adrenergic blockade before exposure (n = 8 dogs, 16 CAPs days, 15 FA days). Blood pressure, heart rate, rate-pressure product, and baroreceptor reflex sensitivity responses were compared using linear mixed-effects models. Results: CAPs exposure increased systolic blood pressure (2.7 ± 1.0 mmHg, p = 0.006), diastolic blood pressure (4.1 ± 0.8 mmHg; p < 0.001), mean arterial pressure (3.7 ± 0.8 mmHg; p < 0.001), heart rate (1.6 ± 0.5 bpm; p < 0.001), and rate-pressure product (539 ± 110 bpm × mmHg; p < 0.001), and decreased pulse pressure (-1.7 ± 0.7 mmHg, p = 0.02). These changes were accompanied by a 20 ± 6 msec/mmHg (p = 0.005) increase in baroreceptor reflex sensitivity after CAPs versus FA. After α-adrenergic blockade, responses to CAPs and FA no longer differed significantly. Conclusions: Controlled exposure to ambient particles elevates arterial blood pressure. Increased peripheral vascular resistance may mediate these changes, whereas increased baroreceptor reflex sensitivity may compensate for particle-induced alterations in blood pressure.