Is atherosclerotic disease associated with organic components of ambient fine particles?

Heart disease is a major killer in western societies; coronary artery disease and atherosclerosis are important contributors to this mortality. Atherosclerosis in mice with a deleted apoE gene (apoE-/-) is accelerated by exposure to ambient ultrafine particles (UFP) which are particles smaller than 180 nm in diameter. UFP contain organic components that are pro-oxidant and may cause or aggravate heart disease. Could removal of these organic constituents mitigate adverse cardiovascular effects? ApoE-/- mice were exposed to concentrated UFP (CAP), CAP from which organic constituents were removed by thermal denuding (deCAP) or purified air (controls) for 5 hr/day, 4 days/week for 8 weeks. Heart rate (HR), heart rate variability (HRV), biomarkers of oxidative stress and the sizes of arterial plaques were measured. Adverse effects were seen in CAP-exposed mice (increased size of arterial plaque, increased oxidative stress and decreased HRV, compared to controls). Adverse effects were not observed in deCAP-exposed mice. Removal of organic constituents from ambient particles resulted in significant reduction of toxic cardiovascular effects of air pollution exposure.