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Fine and ultra-fine particulate matter (PM) are major constituents of urban air pollution and recognized risk factors for cardiovascular diseases. This review examined the effects of PM exposure on vascular tissue. Specific mechanisms by which PM affects the vasculature include inflammation, oxidative stress, actions on vascular tone and vasomotor responses, as well as atherosclerotic plaque formation. Further, there appears to be a greater PM exposure effect on susceptible individuals with pre-existing cardiovascular conditions.

The development and use of nanoparticles have alerted toxicologists and regulators to issues of safety testing. By analogy with ambient air particles, it can be expected that small doses are associated with a small increase in risk of cardiovascular diseases, possibly through oxidative stress and inflammatory pathways. We have assessed the effect of exposure to particulate matter on progression of atherosclerosis and vasomotor function in humans, animals, and ex vivo experimental systems. The type of particles that have been tested in these systems encompass TiO(2), carbon black, fullerene C(60), single-walled carbon nanotubes, ambient air particles, and diesel exhaust particles. Exposure to ambient air particles is associated with accelerated progression of atherosclerosis and vasomotor dysfunction in both healthy and susceptible animal models and humans at risk of developing cardiovascular diseases. The vasomotor dysfunction includes increased vasoconstriction as well as reduced endothelium-dependent vasodilatation; endothelium-independent vasodilatation is often unaffected indicating mainly endothelial dysfunction. Pulmonary exposure to TiO(2), carbon black, and engineered nanoparticles generate vasomotor dysfunction; the effect size is similar to that generated by combustion-derived particles, although the effect could depend on the exposure period and the administered dose, route, and mode. The relative risk associated with exposure to nanoparticles may be small compared to some traditional risk factors for cardiovascular diseases, but superimposed on these and possible exposure to large parts of the population it is a significant public health concern. Overall, assessment of vasomotor dysfunction and progression of atherosclerosis are promising tools for understanding the effects of particulate matter., (© 2011 Informa Healthcare USA, Inc.)

Hormone therapy (HT) is the most effective treatment at present available for climacteric symptoms. As harmful effects were highlighted in recent randomized clinical trials, the risk-benefit ratio does not favor the use of HT for prevention of cardiovascular diseases and bone fractures in postmenopausal women. Nevertheless, experimental and clinical trials suggest that adverse effects of HT basically depend on the estrogen and progestin formulation, dosage, route of administration, patient's age, associated diseases, and duration of treatment. All estrogen formulations and routes of administration have comparable beneficial effects on vasomotor and urogenital symptoms and on bone structure. But adverse effects may differ. Thus, cardiovascular and invasive breast cancer risks are higher with oral estrogen than with transdermal estradiol. However, transdermal estradiol is not free of inconveniences such as differences among individuals in absorption rates, loss of patches due to poor adhesion, and skin irritation. HT requires careful adjustment to each individual patient and continuous monitoring of clinical evolution. In the future, this adjustment and maybe the use of alternative routes such as intranasal could benefit from genetic screening to maximize in each individual the ratio between positive and adverse effects of HT.