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Inhaled ultrafine (nano) particles can translocate into the bloodstream and interact with circulatory cells causing systemic and cardiovascular events. To gain more insight into this potential mechanism, we studied the interaction of diesel exhaust particles (DEP) with human, rat and mouse erythrocytes in vitro. Incubation of erythrocytes with DEP (1, 10 or 100 μg/ml) for 30 min caused the highest hemolytic effect (up to 38%) in rats, compared to small but significant hemolysis in mice (up to 2.5%) and humans (up to 0.7%). Transmission electron microscopy of erythrocytes revealed the presence of variable degrees of ultrafine (nano)-sized aggregates of DEP either internalized and/or adsorbed onto the erythrocytes in the three species. A significant amount of DEP was found in rat and mouse (but not human) erythrocytes. Lipid erythrocyte susceptibility to in vitro peroxidation measured by malondialdehyde showed a significant and dose-dependent increase in erythrocytes of rats, but not humans or mice. Unlike in human erythrocytes, total antioxidant status (TAS) and superoxide dismutase (SOD) activity in rats were significantly and dose- dependently decreased. In mouse erythrocytes, DEP caused a decreased in SOD (at 10 μg/ml) and TAS (at 100 μg/ml) activities. In conclusion, DEP caused species-dependent erythrocyte hemolysis and oxidative stress, and were either taken up and/or adsorbed onto the red blood cells. Rat (and to a lesser degree mouse) erythrocytes were susceptible to DEP. Human erythrocytes showed the highest resistance to the observed effects. These species difference should be noted when using rats and mice blood as models for humans., (Copyright © 2012 S. Karger AG, Basel.)

Abstract: Several epidemiological studies have shown that acute exposure to particulate air pollution is associated with increases in cardiovascular morbidity and mortality, and that these effects are especially exacerbated among individuals with pre-existing compromised cardiovascular function such as hypertension. This study was undertaken to determine the cardiovascular effect of diesel exhaust on TO mice made hypertensive by implanting osmotic minipump infusing angiotensin II or vehicle (control). On day 13, the animals were intratracheally instilled with either DEP (15μg/mouse) or saline. 24h later, pulmonary exposure to DEP had significantly decreased the systolic blood pressure (SBP) in hypertensive (HT) mice (P <0.01), but not in normotensive (NT) mice. The number of leukocytes and red blood cells, and the plasma interleukin 6 concentration in plasma, however, were not affected in any of the animals. The PaO2 was decreased, and PaCO2 increased in DEP-treated HT mice compared to NT mice treated with DEP (P <0.05). The number of circulating platelets was significantly increased in DEP-treated HT versus saline-treated HT and DEP-treated NT mice. Moreover, in NT mice, DEP exposure induced a prothrombotic effect in pial arterioles compared with saline-treated NT mice (P <0.05). Interestingly, in DEP-treated HT mice, the prothrombotic events were significantly aggravated compared with saline-treated HT and DEP-treated NT mice. The direct addition of DEP (0.1–1μg/ml) to untreated mouse blood significantly induced in vitro platelet aggregation in a dose-dependent fashion, and these effects were more pronounced in blood of HT mice. In vitro exposure to DEP (0.25–1μg/ml) led to activated intravascular coagulation, an effect that was confirmed by a shortening of both the activated partial thromboplastin time (aPTT) and the prothrombin time (PT). The effect of DEP on aPTT was potentiated in the plasma of HT mice. It can be concluded that the thrombotic events caused by DEP are exacerbated by hypertension in mice. Our findings, therefore, provide a possible plausible explanation for the cardiovascular morbidity and mortality accompanying urban air pollution. [Copyright &y& Elsevier]

Studies the cloning and expression of the sodium/hydrogen exchanger (NHE) from Amphiuma red blood cells. Cloning of Amphiuma NHE cDNA; Comparisons of atNHE1 with other NHE sequences; Functional characterization of Amphiuma, human, and chimeric NHE transfectants.