Ozone and cardiovascular injury

Abstract

Air pollution is increasingly recognized as an important and modifiable determinant of cardiovascular diseases in urban communities. The potential detrimental effects are both acute and chronic having a strong impact on morbidity and mortality. The acute exposure to pollutants has been linked to adverse cardiovascular events such as myocardial infarction, heart failure and life-threatening arrhythmias. The long-terms effects are related to the lifetime risk of death from cardiac causes. The WHO estimates that air pollution is responsible for 3 million premature deaths each year. The evidence supporting these data is very strong nonetheless, epidemiologic and observational data have the main limitation of imprecise measurements. Moreover, the lack of clinical experimental models makes it difficult to demonstrate the individual risk. The other limitation is related to the lack of a clear mechanism explaining the effects of pollution on cardiovascular mortality. In the present review we will explore the epidemiological, clinical and experimental evidence of the effects of ozone on cardiovascular diseases.The pathophysiologic consequences of air pollutant exposures have been extensively investigated in pulmonary systems, and it is clear that some of the major components of air pollution (e.g. ozone and particulate matter) can initiate and exacerbate lung disease in humans [1]. It is possible that pulmonary oxidant stress mediated by particulate matter and/or ozone (O3) exposure can result in downstream perturbations in the cardiovasculature, as the pulmonary and cardiovascular systems are intricately associated, and it is well documented that specific environmental toxins (such as tobacco smoke [2]) introduced through the lungs can initiate and/or accelerate cardiovascular disease development. Indeed, several epidemiologic studies have proved that there is an association between PM and O3 and the increased incidence of cardiovascular morbidity and mortality [3]. Most of the evidence comes from studies of ambient particles concentrations. However, in Europe and elsewhere, the air pollution profile has gradually changed toward a more pronounced photochemical component. Ozone is one of the most toxic components of the photochemical air pollution mixture. Indeed, the biological basis for these observations has not been elucidated.In the present review, the role of ozone as chemical molecule will be firstly considered. Secondly, pathogenetic mechanisms connecting the atmospheric ozone level and cardiovascular pathology will be examined. Thirdly, the literature relating hospitalization frequency, morbidity and mortality due to cardiovascular causes and ozone concentration will be studied. The correlation between ozone level and occurrence of acute myocardial infarction will be eventually discussed.

Impact of meteorological parameters and air pollution on emergency department visits for cardiovascular diseases in the city of Zagreb, Croatia

“…Results of our study revealed a negative correlation between O 3 concentrations and CVD-related emergency visits, which is in line with previous studies (22)(23)(24). However, many studies showed destructive effects of this pollutant on the cardiovascular system.…”

“…Several review studies (2,9,22) showed that O 3 was one of the most toxic compounds of mixed photochemical smog. Results of our study revealed a negative correlation between O 3 concentrations and CVD-related emergency visits, which is in line with previous studies (22)(23)(24).…”

Ozone short-term exposure and acute coronary events: A multicities study in Tuscany (Italy)

“…Increased risk of paroxysmal atrial fibrillation episodes (Rich et al, 2005), ventricular arrhythmias (Rich et al, 2006), reduction of heart rate variability, and increased resting heart rate have been reported (Zanobetti et al, 2010). A recent review of Srebot and colleagues (Srebot et al, 2009) extensively examined the available knowledge on the pathways connecting ozone and cardiovascular adverse effects, including influence on macrovascular diameter and tone, increased peripheral blood pressure, short-term autonomic imbalance, effects on inflammation response, and increased oxidative stress in the cardiovascular system.…”

Conceptual model for assessing criteria air pollutants in a multipollutant context: A modified adverse outcome pathway approach

“…Less is known, however, about mechanisms mediating O 3 -induced cardiovascular responses (U.S. EPA, 2013b). Preliminary evidence implicates altered autonomic tone, systemic inflammation, vascular oxidative stress, and endothelial/vascular dysfunction (Srebot et al, 2009).…”