Bernini W

Vascular prostacyclin is increased in patients ingesting omega-3 polyunsaturated fatty acids before coronary artery bypass graft surgery.

Interest in the antithrombotic potential of diets enriched with fish oil-derived polyunsaturated fatty acids (omega-3 PUFAs) prompted us to examine how these fatty acids, when taken preoperatively, affect hemostasis, plasma lipid levels, and production of prostacyclin (PGI2) by vascular tissues in atherosclerotic patients undergoing coronary artery bypass graft surgery. Fifteen patients with angiographically proven coronary artery disease received 3 g/day eicosapentaenoic acid and 1.3 g/day docosahexaenoic acid as capsules of purified fish oil for 28 days before surgery. Platelet aggregation induced by low concentrations of ADP, collagen, and epinephrine decreased (p less than 0.05) and serum thromboxane B2 decreased 36% (p less than 0.01) from baseline values. Bleeding times increased 40% (p less than 0.01) from baseline. Serum triglycerides decreased 50% (p less than 0.05) without a change in total serum cholesterol. Spontaneous production of PGI2 measured as 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), its stable hydrolytic product, by saphenous vein and aortic and atrial tissues obtained at surgery was greater in tissues from patients receiving omega-3 PUFA supplements than in tissues from matched controls (13.8 +/- 2.2 versus 8.6, 21.0 +/- 3.1 versus 11.5 +/- 2.1, and 166 +/- 13 versus 102 +/- 15 ng/g, respectively, all p less than 0.05). Arachidonate-stimulated production of PGI2, as indicated by increased levels of 6-keto-PGF1 alpha, was increased. Despite changes in platelet function, bleeding time, and vascular PGI2, the perioperative blood loss was not increased in subjects receiving fish oil supplements. Thus, omega-3 PUFAs at moderate dosages may exert antithrombotic effects by increasing prostacyclin production by vessel walls as well as by direct inhibition of platelet activity.

Low-Density Lipoprotein Level Reduction by the 3-Hydroxy-3-Methylglutaryl Coenzyme-A Inhibitor Simvastatin Is Accompanied by a Related Reduction of F2-Isoprostane Formation in Hypercholesterolemic Subjects No Further Effect of Vitamin E

Background—Both statins and vitamin E, by reducing the rate of lipid peroxidation, may interfere with oxidative stress, but the impact of their combination is unknown. Methods and Results—We randomized 43 hypercholesterolemic patients (21 men, 22 women, age 63±11 years) to either simvastatin, to achieve >20% reduction of total cholesterol, or simvastatin plus 600 mg/d vitamin E for 2 months. Patients were then crossed over to the alternative treatment. Lipid parameters documented patients’ compliance to simvastatin, whereas plasma levels of vitamin E documented compliance and absorption of vitamin E. We assessed urinary excretion of the isoprostane 8-iso-prostaglandin F2&agr; (8-iso-PGF2&agr;) as an in vivo index of oxidative stress at baseline and after each month of therapy. 8-Iso-PGF2&agr; was significantly reduced by simvastatin, from 361±148 pg/mg creatinine (mean±SD) at baseline to 239±124 pg/mg creatinine after 1 month. The addition of vitamin E did not reduce such levels any further (256±125 after 1 month). Linear regression analysis showed a weak inverse relationship of 8-iso-PGF2&agr; with vitamin E levels but a much stronger relationship with LDL cholesterol (R2=0.162;P <0.001). Conclusions—In hypercholesterolemic patients, LDL cholesterol is a major correlate of oxidative stress. Concomitant with LDL cholesterol reduction, simvastatin causes a drastic reduction of oxidative stress to a level that is not further reduced by the addition of vitamin E. Results of clinical trials with vitamin E may have been hampered by inadequate knowledge of the background level of lipid peroxidation, which is a major determinant of vitamin E bioactivity.

Soluble E-selectin in essential hypertension: A correlate of vascular structural changes*

BACKGROUND Increased expression of the endothelial leukocyte adhesion molecule E-selectin is implicated in vascular disease and may accompany the development of hypertension. We evaluated plasma soluble (s) E-selectin to assess its relationship with endothelium-dependent and endothelium-independent vasodilation in patients with hypertension. METHODS Thirty-one previously untreated and uncomplicated essential hypertensive patients were compared with 16 normotensive controls for changes in forearm blood flow (by strain-gauge plethysmography) in response to brachial artery infusion of the endothelium-dependent vasodilator acetylcholine, and of the endothelium-independent vasodilator sodium nitroprusside. As an index of structural changes, minimal forearm vascular resistances were calculated as the ratio between maximal vasodilation after 13 min of ischemia and mean blood pressure. RESULTS Responses to acetylcholine were significantly lower and minimal forearm vascular resistances higher in hypertensives versus controls, whereas responses to nitroprusside were comparable. Baseline sE-selectin concentrations were (mean +/- SEM) 37.4 +/- 1.8 ng/mL in hypertensives and 27.8 +/- 0.7 ng/mL in normotensives (P < .001). In essential hypertensive patients, a significant (P < .01) correlation with the response to nitroprusside (r = -0.47) was found, but not with the response to acetylcholine or minimal forearm vascular resistances. sE-selectin was also positively correlated with age and LDL cholesterol. At multivariate analysis, sE-selectin remained significantly correlated with nitroprusside responses and LDL cholesterol. CONCLUSIONS In patients with essential hypertension, plasma levels of sE-selectin are higher than in normotensive controls and mostly related to structural vascular changes.

Inhibition of platelet function by injectable isosorbide dinitrate.

The possibility that isosorbide dinitrate (ISDN) inhibits platelet function in humans has been explored in vitro and in vivo. Incubation of citrated platelet-rich plasma from healthy subjects with scalar concentrations (1.25, 12.5 and 125 micrograms/ml) of ISDN for 5 and 10 minutes resulted in a decrease in platelet aggregation after ADP, adrenaline, and arachidonic acid at the highest drug concentration (mean decrease: 72% [p less than 0.01], 56% [p less than 0.05] and 62% [p less than 0.05], respectively, with the 10-minute incubation). Also, a significant reduction (30%) in generated thromboxane (TX)B2 levels was observed after arachidonic acid (p less than 0.01). ISDN was then infused at rate of 4 mg/hour for 30 minutes in 11 patients with angina and at a rate of 30 mg/hour for 20 minutes in 8. The smaller dose, which caused minor changes in arterial pressure and heart rate, was accompanied by a marked, significant decrease in ADP- and adrenaline-induced aggregation, with a nadir at 60 minutes from the infusion stop (decreases of 40% and 51% respectively). Circulating platelet aggregates also decreased, with a minimum (-41%, p less than 0.05) at the end of the infusion. The higher infusion rate, causing marked hemodynamic effects, was not accompanied by the occurrence of clear antiplatelet effects. Thus, ISDN can affect platelet function both in vitro and in vivo. The in vivo effect occurs at lower concentrations than in vitro but is blunted when a marked hemodynamic response occurs.

111In Platelet Scintigraphy for the Noninvasive Detection of Carotid Plaque Thrombosis

Background and Purpose— Thrombosis on atherosclerotic lesions in the large extracranial arteries is the main cause of embolization in the distal cerebral circulation and thus is involved in the pathogenesis of ischemic stroke. The assessment of biological characteristics of lesions that are predictive of thrombotic complications might help in stratification of the risk for stroke but is currently imperfect. Methods— We compared the performance of 111In-platelet scintigraphy with blood pool subtraction, ultrasound-based tissue texture analyses, and transcranial Doppler techniques in their ability to predict the occurrence of superficial thrombosis or the presence of a lipid pool in carotid artery plaque specimens removed at the time of carotid endarterectomy in 22 patients with unilateral carotid artery stenosis of >70%. Results— Positivity at 111In-platelet scintigraphy was present in 8 patients and correctly identified the presence of thrombosis superimposed on a complicated plaque. Neither tissue texture analysis nor emboli detection by transcranial Doppler, performed in 12 patients, significantly identified plaque thrombosis. None of the techniques used were able to detect the presence of a significant lipid pool inside the plaque. Conclusions— Indium-platelet scintigraphy is an accurate noninvasive diagnostic tool to detect thrombotic complications in carotid plaques. Prospective studies should assess its ultimate value in risk stratification, possibly to guide the decision of whether to perform endarterectomy in selected patient categories.

Inhibition of platelet function during in vivo infusion of isosorbide mononitrates: Relationship between plasma drug concentration and hemodynamic effects

Isosorbide monitrates (IS-2-MN and IS-5-MN), hepatic metabolites of isosorbide dinitrate, inhibit platelet function in vitro very differently, with IS-2-MN being much more potent than IS-5-MN. To assess their antiplatelet properties in vivo and to compare time and dosage requirements, we infused both IS-2-MN and IS-5-MN for 30 minutes, on 2 separate days, into nine patients with stable coronary artery disease, at rates of 4 mg/hr (n = 4) and 8 mg/hr (n = 5). Two additional patients received IS-5-MN at 16 mg/hr. Platelet aggregation and thromboxane (TX) B2 generation in response to various agonists, drug plasma concentrations, and blood pressure were monitored throughout the study. A significant decrease in platelet aggregation and TXB2 production by adenosine diphosphate and adrenaline occurred in seven of nine patients receiving IS-2-MN and in 7 of 11 patients receiving IS-5-MN. Response was dose related, with more patients responding at 8 mg/hr to IS-2-MN (five of five) than to IS-5-MN (three of five), and was maximum at the end of the infusion time, corresponding to peak plasma levels. Patients responding to drug infusions with an inhibition of platelet function were characterized by a greater vascular responsiveness compared to nonresponders, since the decrease in systolic blood pressure (mean +/- SEM) was significantly greater in the former (15.4 +/- 3.2) than in the latter (2.5 +/- 2.1, p less than 0.05). Therefore both mononitrates, when administered at infusion rates between 8 and 16 mg/hr, are accompanied by a consistent inhibition of adenosine diphosphate- and adrenaline-induced aggregation and TX generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Sulfido‐peptide leukotrienes in coronary heart disease – relationship with disease instability and myocardial ischaemia

Eur J Clin Invest 2010; 40 (3): 258–272

The double bond in unsaturated fatty acids is the necessary and sufficient requirement for the inhibition of expression of endothelial leukocyte adhesion molecules through interference with nuclear factor-κB activation

ConclusionsThese results indicate that the single double bond present in oleic acid is a necessary and sufficient requirement for FA inhibition of endothelial activation. Since this occurred independent of the stimuli used and was present also with PMA, bypassing membrane receptors, these results point to an interference with a common signal transduction pathway for cytokine signaling. These results are accounted for by an inhibition of NF-χB activation, here demonstrated at the same concentrations required for the inhibition of surface protein. Relevance of these observations to explaining the alleged beneficial antiatherogenic effects of the Mediterranean diet, in which oleic acid in olive oil is a major nutritional component, could lie in the relatively selective displacement of saturated FA by oleate addition to endothelial cells which was also shown to occur in our system. Thus, an increase in the unsaturation index in cell membranes by oleic acid-rich diets is theoretically additive to the effects of polyunsaturated FA. By these mechanisms, monocyte recruitment in response to atherogenic stimuli might be decreased (3).

Omega-3 Fatty Acid Supplementation and Lipoprotein(a) Concentrations in Patients with Chronic Glomerular Diseases

Renal disease patients often exhibit alterations in the lipid profile which may become an important risk of accelerated atherosclerosis and contribute to disease progression. Among such alterations, increased levels of lipoprotein(a) [Lp(a)] are common and may be related, in part, to the degree of proteinuria. Omega-3 polyunsaturated fatty acids (omega-3 FA) have been reported to decrease Lp(a) concentrations in nonrenal subjects. In addition, they have recently been shown to reduce proteinuria in patients with chronic glomerular disease. We therefore tested the hypothesis that omega-3 FA treatment in patients with chronic glomerular disease may reduce Lp(a) concentrations. Eight patients (2 with membranous glomerulonephritis, 6 with focal glomerular sclerosis) were submitted to a total of 13 six-week courses of treatment with omega-3 FA, at a dose of 3 g/day with a triglyceride preparation (n = 4) and of 7.7 g/day with an ethyl-ester preparation (n = 9). Both treatments significantly increased the proportions of omega-3 to omega-6 FA in total serum lipids, documenting compliance to treatment. Both treatments were also effective in decreasing serum thromboxane (from mean 490 +/- (SEM) 70 to 325 +/- 49 ng/ml, p < 0.05, in the high-dose group) and prolonging the bleeding time (from 5.8 +/- 0.4 to 7.7 +/- 0.5 min, p < 0.05, in the high-dose group), thus documenting the biological efficacy of treatment. However, despite a significant reduction in serum triglyceride levels (from 137 +/- 20 to 104 +/- 19 mg/dl in the high-dose group), Lp(a) concentrations did not change (292 +/- 120 U/l before, 315 +/- 130 U/l after the high-dose therapy). Treatment-related changes in proteinuria (from 2.9 +/- 0.5 to 2.1 +/- 0.7 g/24 h) were not related at all to changes in Lp(a) levels. We conclude that omega-3 FA do not decrease Lp(a) concentrations in renal patients with chronic glomerular diseases and that Lp(a) levels are unlikely to be related to the degree of proteinuria within the short-term modifications induced by omega-3 FA.

Anti-D treatment for chronic immune thrombocytopenic purpura : clinical and laboratory aspects

We used low-dose anti-D immunoglobulins for home treatment of Rh+ adult patients with chronic immune thrombocytopenic purpura (ITP). After informed consent, 15 unselected outpatients (ten males and five females, aged 22 to 72), affected by chronic ITP with negative HIV test, were given intramuscular injection of 900-1500 micrograms of anti-Rh0 (D) IgG over 3 days every month for 2 or 3 consecutive months. Platelet count (mean +/- SD) significantly increased from basal value of 17,000 +/- 9,000/microL to 72,000 +/- 55,000/microL at the end of treatment. Eight patients achieved a rise in platelet count above 50,000/microL (five above 100,000/microL) and two of them maintained the increase longer than 6 months without further anti-D administration. Three patients responsive to the first cycle responded to further treatment with substantially identical results. Seven patients had no response. Four of them had not responded to previous glucocorticoid and intravenous IgG therapy. Direct antiglobulin test became strongly positive in all patients and mean serum haptoglobin decreased from a basal value of 118 +/- 59 to 61 +/- 43 mg/dL; nevertheless no clinically overt hemolysis was observed in any patient, there was no rise of serum indirect bilirubin and hemoglobin level was unchanged (mean +/- SD basal level 13.6 +/- 2.2 g/dL; after anti-D 13.9 +/- 1.2 g/dL). No hematoma developed at the injection site, and no other side effects occurred. Our results show that anti-D therapy is effective in the majority of patients well tolerated, and feasible as home treatment: thus it can be recommended as a cheap and safe alternative treatment in ITP Rh+ patients.