Inhalation of Simulated Smog Atmospheres Affects Cardiac Function in Mice

Abstract

The health effects of individual criteria air pollutants have been well investigated. However, little is known about the health effects of air pollutant mixtures that more realistically represent environmental exposures. The present study was designed to evaluate the cardiac effects of inhaled simulated smog atmospheres (SA) generated from the photochemistry of either gasoline and isoprene (SA-G) or isoprene (SA-Is) in mice. Four-month-old female mice were exposed for 4 h to filtered air (FA), SAG , or SA-Is. Immediately and 20 h after exposure, cardiac responses were assessed with a Langendorff preparation using a protocol consisting of 20 min of global ischemia followed by 2 h of reperfusion. Cardiac function was measured by index of left-ventricular developed pressure (LVDP) and cardiac contractility (dP/dt) before ischemia. Pre-ischemic LVDP was lower in mice immediately after SA-Is exposure (52.2±5.7 cm H 2 O compared to 83.9±7.4 cm H 2 O after FA exposure; p=0.008) and 20 h after SAG exposure (54.0±12.7 cm H 2 O compared to 79.3±7.4 cm H 2 O after FA exposure; p=0.047). Pre-ischemic left ventricular contraction dP/dt max was lower in mice immediately after SA-Is exposure (2025±169 cm H 2 O/sec compared to 3044±219 cm H 2 O/sec after FA exposure; p<0.05) and 20 h after SAG exposure (1864±328 cm H 2 O/sec compared to 2650±258 cm H 2 O/sec after FA exposure; p=0.05). In addition, SAG reduced the coronary artery flow rate 20 h after exposure compared to the FA control. This study demonstrates that acute SAG and SA-Is exposures decrease LVDP and cardiac contractility in mice, indicating that photochemically-altered atmospheres affect the cardiovascular system.

Fatty Dihydropyridines With Anti-Hypertensive and Cardioprotective Potential During Ischemia and Reperfusion

“…The study of the isolated heart is used in several types of tests being extremely useful in the translational evaluation of these pharmacological tests [32,33]. According to Tong et al [34], heart retrograde perfusion models are ex vivo methods of clinical relevance for the study of myocardial infarction to evaluate function and injury.…”

Cardiovascular effects of diesel exhaust inhalation: photochemically altered versus freshly emitted in mice

“…In a clinical study Madden et al (Madden et al 2014) showed that the combination of O 3 and DE co-exposure produced greater than additive of effects of O 3 and DE on lung function decrements in healthy adults, suggesting that a potential interaction between the gaseous and particulate pollutants inducing greater than additive effects. In addition, animal studies demonstrated that the cardiovascular effects of atmosphere mixtures exposure were dominated by the gaseous components (McIntosh-Kastrinsky et al 2013, Tong et al 2018, Hazari et al 2018). However, Kurhanewicz et al (Kurhanewicz et al 2014) found that co-exposure of O 3 with fine or ultrafine PM produced varied cardiac responses, suggesting that cardiovascular effects of particle-gas co-exposures are not simply additive or even generalizable.…”