Nanoparticles and the cardiovascular system: a critical review

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Nanoparticles and the cardiovascular system: a critical review Nanoparticles (NPs) are tiny particles with a diameter of less than 100 nm. Traffic exhaust is a major source of combustion-derived NPs (CDNPs), which represent a significant component in urban air pollution. Epidemiological, panel and controlled human chamber studies clearly demonstrate that exposure to CDNPs is associated with multiple adverse cardiovascular effects in both healthy individuals and those with preexisting cardiovascular disease. NPs are also manufactured from a large range of materials for industrial use in a vast array of products including for use as novel imaging agents for medical use. There is currently little information available on the impacts of manufactured NPs in humans, but experimental studies demonstrate similarities to the detrimental cardiovascular actions of CDNPs. This review describes the evidence for these cardiovascular effects and attempts to resolve the paradox between the adverse effects of the unintentional exposure of CDNPs and the intentional delivery of manufactured NPs for medical purposes. KEYWORDS: atherosclerosis n atherothrombosis n cardiovascular n combustion n engineered n inflammation n lungs n manufactured n nanoparticles

There is a long history of research demonstrating that inhalation of a variety of environmental and occupational particles can lead to lung disease after they become airborne in workplaces or the environment and get inhaled into the lungs [1] . Particles can be categorized in various ways, however, the classification on the basis of size is a useful one, especially because the toxicity (on a mass basis) of particles increases as their size decreases [2] . The terms nanoparticles (NPs) and ultrafine particles describe particles in the same size range (less than 100 nm), but the former can be defined as manufactured and ultrafine particles are sometimes defined as those arising in ambient air; in this review they are viewed as interchangeable depending on the context. NPs or ultrafine particles are defined as particles with at least two dimensions less than 100 nm; NPs have three dimensions less than 100 nm and nanofibers have two dimensions less than 100 nm and the third dimension can be tens or hundreds of microns in length. In general this review deals with NPs, not nanofibers. Particle size affects the aerodynamic behavior of particles and, therefore, is an important factor influencing the deposition of particles in the lung, and specifically, the region of deposition. Fine (~0.1–2.5 µm) and coarse (~2.5–10 µm) compact particles deposit by sedimentation or impaction, while NPs (
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