Atherosclerosis and vasomotor dysfunction in arteries of animals after exposure to combustion-derived particulate matter or nanomaterials

Abstract

Exposure to particulate matter (PM) from traffic vehicles is hazardous to the vascular system, leading to clinical manifestations and mortality due to ischemic heart disease. By analogy, nanomaterials may also be associated with the same outcomes. Here, the effects of exposure to PM from ambient air, diesel exhaust and certain nanomaterials on atherosclerosis and vasomotor function in animals have been assessed. The majority of studies have used pulmonary exposure by inhalation or instillation, although there are some studies on non-pulmonary routes such as the gastrointestinal tract. Airway exposure to air pollution particles and nanomaterials is associated with similar effects on atherosclerosis progression, augmented vasoconstriction and blunted vasorelaxation responses in arteries, whereas exposure to diesel exhaust is associated with lower responses. At present, there is no convincing evidence of dose-dependent effects across studies. Oxidative stress and inflammation have been observed in the arterial wall of PM-exposed animals with vasomotor dysfunction or plaque progression. From the data, it is evident that pulmonary and systemic inflammation does not seem to be necessary for these vascular effects to occur. Furthermore, there is inconsistent evidence with regard to altered plasma lipid profile and systemic inflammation as a key step in vasomotor dysfunction and progression of atherosclerosis in PM-exposed animals. In summary, the results show that certain nanomaterials, including TiO₂, carbon black and carbon nanotubes, have similar hazards to the vascular system as combustion-derived PM.

Keywords:

• Air pollution
• atherosclerosis
• nanomaterials
• particulate matter
• vasomotor dysfunction

Acknowledgements

The authors gratefully acknowledge the comments and suggestions of five reviewers selected by the Editor and unknown to the authors. Their comments and suggestions were of immense value in revising the manuscript.

Declaration of interest

The affiliation of the authors is as shown on the cover page. This paper was prepared during the normal course of authors' employment. The strategy for the literature review, the evaluation of the literature and the conclusions drawn are the exclusive professional work of the authors. The authors have obtained financial support from The Danish Council of Independent Research (Medical Sciences, Grant no. 12–126262) and the Danish Working Environment Research Foundation (Danish Center for Nanosafety, Grant no. 20110092173–3). None of the authors have appeared in legal proceedings or regulatory proceedings related to the contents of the paper. The paper is a professional work product of the authors and not necessarily that of the employers.