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Background: Contrast media (CM) administrated during percutaneous coronary intervention (PCI) is associated with endothelial dysfunction (ED) and systemic vascular injury. Brain natriuretic peptide (BNP) administration 24 hours post PCI decreases ED. Aims: To evaluate 1.The ability of human BNP (hBNP) infusion during PCI, to prevent ED in acute coronary syndrome's (ACS) patients post the PCI. 2. The effect of CM on human coronary microvascular endothelial cells (HCMEC).3. Explain ED by invitro study. Methods and results (in vivo): Non-ST elevation ACS patients who underwent PCI (111) were randomized into 2 groups: an hBNP group who received hBNP infusion during the procedure (n=44), and control group who received nitroglycerin (n=67). Flow mediated dilatation (FMD) (by ≥2.5%), BNP, corin, serum creatinine (sCr) and estimate Glomerular Filtration Rate (eGFR), before and 24 hr after operative were recorded, starting with the same baseline. The post PCI FMD and eGFR were significantly reduced in the control group (p=0.05, 0.002) but not in the hBNP group (p=0.16, 0.4). BNP, corin and sCr increased significantly in the control group (p=0.001, 0.003, 0.0002 respectively) but not in hBNP group (p=0.09, 0.07, 0.18). Methods and results (in vitro): HCMEC were treated with CM (10%) in the presence and absence of BNP. eNOS, corin and cGMP levels were measured by ELISA and the results were compared to untreated cells. In both treatments eNOS was significantly reduced (p=0.001) and corin was significantly increased (p=0.002). cGMP was not affected by CM treatment (p=0.278), but was increased significantly (p=0.001) by hBNP combination. cGMP immuno-flourescence staining of HCMEC showed distorted cellular cGMP appearance by CM treatment, that was corrected in the combination with hBNP with accentuated subsarcolemmal staining. Conclusions: CM reduces eNOS level in HCMEC. Therefore, reduced in NO-cGMP pathway's products, probably is the mechanism that induces ED in-vivo. BNP treatment reduces FMD diminution and kidney injury post PCI. A compensatory rise in corin that increases BNP as well as the hBNP administration, invivo and invitro, maintains cytosolic cGMP via NP-cGMP pathway, and compensates for NO-cGMP loss, (reduced sGC) and thus prevents ED.

BACKGROUND The coronary microvasculature may be abnormal even in the presence of angiographically normal epicardial arteries. Abnormalities of small coronary vessels have been invoked as a cause of angina. METHODS AND RESULTS To quantitatively evaluate the morphology of capillaries in patients with idiopathic dilated cardiomyopathy (DCM) or the syndrome of angina and small vessel disease (SVD), we performed electron microscopic morphometry of capillaries in right ventricular biopsy samples taken from 32 patients. Ten had angina, normal epicardial coronary arteries, and evidence for SVD; 12 had DCM; and 10 had normal hearts. In patients with DCM, the ratio of microvessels to myocytes was not different than that of controls (0.49 +/- 0.06 versus 0.51 +/- 0.05). Mean cross-sectional areas of the capillaries (lumen plus wall) and lumen were significantly greater than those of controls (45.3 +/- 15.1 versus 22.7 +/- 8.3 micron 2, p less than 0.001; 17.6 +/- 6.9 versus 11.6 +/- 6.2 micron 2, p less than 0.05, respectively). Fibrous content of the myocardium, as assessed by quantitative light microscopy, was significantly increased (16.3 +/- 3.3% versus 5.0 +/- 2.4%, p less than 0.001). In contrast, in patients with SVD, the capillary-to-myocyte ratio was reduced (0.33 +/- 0.08, p less than 0.001). Although mean cross-sectional areas of the entire capillary (32.4 +/- 19.7 micron 2) and the lumen (8.9 +/- 7.8 micron 2) were not statistically different than those of controls, there was an absence of capillaries less than 15 micron 2 in cross-sectional area, and the frequency distribution of the lumen area was skewed to the left. Swollen endothelial cells frequently encroached upon the lumen. There was a mild increase in fibrous content (9.5 +/- 3.7%, p less than 0.05). CONCLUSIONS Enlarged capillaries and a normal ratio of capillaries to myocytes appear to be features of DCM. Of the patients with SVD, there was both a relative lack of capillaries and capillary lumen narrowing from swollen endothelium. These changes may induce ischemia and angina and may result in mild fibrosis.

A70-year-old patient with no apparent heart disease was admitted after a motor-vehicle accident and had right hemispheric intracerebral hemorrhage with compression over the lateral ventricle (Figure 1⇓). The patient was admitted to an intensive care unit, where an ECG was taken. ECG repolarization abnormalities were followed by repeated …

The effects of sodium pump inhibition produced by exposure to the cardiac glycosides, ouabain or dihydroouabain, or by reduction in extracellular potassium to 1.0 mM, on contractile state and sodium-calcium exchange were studied in primary monolayer cultures of chick embryo ventricular cells. Ouabain, 10(-6)M, dihydroouabain, 5 X 10(-5)M, and extracellular potassium of 1.0 mM all induced similar and prominent positive inotropic effects. These effects were accompanied, in each case, by 40-50% inhibition of the rate of active uptake of 42K and by similar increases in steady state sodium content. Stimulation of the rate of 45Ca uptake on exposure to zero extracellular sodium occurred in response to extracellular potassium (1.0 mM) or to glycoside concentrations that induced a positive inotropic effect and sodium-potassium pump inhibition. Reactivation of the sodium pump after return from 1.0 to 4.0 mM extracellular potassium was rapid and was associated with membrane hyperpolarization and slowing of spontaneous beating rate. With pump reactivation under these circumstances, the time course of disappearance of stimulation of sodium-calcium exchange on exposure to zero extracellular sodium was similar to the time course of loss of the positive inotropic effect. Under physiological conditions (4.0 mM extracellular potassium), exposure to positively inotropic but nontoxic concentrations of ouabain or dihydroouabain caused a small but consistent increase in unidirectional calcium influx, but had no discernible effect on calcium efflux. Since similar inotropic effects were produced for comparable degrees of glycoside or low extracellular potassium-induced sodium pump inhibition and increases in cellular sodium content, sodium pump inhibition rather than a glycoside-specific change in calcium binding appears to underlie the inotropic response. These findings are further consistent with the view that the primary mechanism of the positive inotropic effects of digitalis and low extracellular potassium in this experimental preparation is sodium pump inhibition resulting in increased intracellular sodium. We suggest that increased calcium influx via sodium-calcium exchange is the principal mechanism whereby increased intracellular sodium results in enhanced calcium availability to the myofibrils, but an additional effect on calcium efflux is not excluded.