Carvedilol prevents low-density lipoprotein (LDL)-enhanced monocyte adhesion to endothelial cells by inhibition of LDL oxidation

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Early use of beta-blockers attenuates systemic inflammatory response and lung oxygenation impairment after distal type acute aortic dissection

We have reported that serum C-reactive protein (CRP) elevation is an independent predictor of lung oxygenation impairment (LOI) after distal type acute aortic dissection (AAD). Systemic activation of the inflammatory system after aortic injury may play a role in the development of LOI. The aim of this study is to clarify the effect of beta-blockers on systemic inflammation and the development of LOI after distal type AAD. A total of 49 patients, who were admitted with distal type AAD and treated conservatively, were examined. White blood cell (WBC) count, serum CRP level, and arterial blood gases were measured serially. Forty patients received beta-blocker treatment within 24 h of the onset, while 9 patients received no beta-blocker treatment. Maximum WBC count, maximum CRP level, lowest PaO₂/FiO₂ (P/F) ratio, and patient background were compared between the two groups. There was no difference between the groups according to age, sex, coronary risk factors, blood pressure, serum level of CRP, WBC count, and oxygenation index on admission. Beta-blocker treatment was associated with lower maximum WBC count (P = 0.0028) and lower maximum serum CRP level (P = 0.0004). The minimum P/F ratio was higher in patients with beta-blocker treatment than in those without (P = 0.0076). Multivariate analysis revealed that administration of a beta-blocker was an independent negative determinant of LOI (P/F ratio ≤200 mmHg). In conclusion, early use of beta-blockers prevented excessive inflammation and LOI after distal type AAD, suggesting a pleiotropic effect of beta-blockers on the inflammatory response after AAD.

Optimal β-blocker for prevention of atrial fibrillation after on-pump coronary artery bypass graft surgery: Carvedilol versus metoprolol

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass graft (CABG) surgery. It has been shown that prophylactic oral beta-blocker administration reduces the incidence of post-CABG AF. However, the optimal beta-blocker has not been identified.

OBJECTIVE

This study sought to determine whether oral carvedilol (with its unique anti-inflammatory and antioxidant properties) is more effective than oral metoprolol for prevention of AF after CABG surgery.

METHODS

Between April 2006 and December 2006, 120 patients (63 men, mean age 61 +/- 9.4 years) who were scheduled to undergo their first on-pump CABG were enrolled in this study. The patients were randomized in a prospective 1:1 manner to receive either oral carvedilol (n = 60) or oral metoprolol (n = 60). The end point of the study was the occurrence of the new-onset AF during the first 5 days after CABG.

RESULTS

AF occurred in 29 of 120 patients (24.0%). The incidence of postoperative AF was 15.0% (9 of 60) in the carvedilol group and 33% (20 of 60) in the metoprolol group (P = .022). The carvedilol group was treated with mean daily dose of 46 +/- 9 mg and metoprolol group with mean daily dose of 93 +/- 11 mg. There were no differences between the study groups regarding any known preoperative, perioperative, or postoperative characteristics (all values were P >.05). No significant adverse effect was observed in either group.

CONCLUSION

This prospective study suggested that oral carvedilol is more effective than oral metoprolol in the prevention of AF after on-pump CABG. It is well tolerated when started before and continued after the surgery. However, further prospective studies are needed to clarify this issue.

Metoprolol treatment decreases tissue myeloperoxidase activity after spinal cord injury in rats

Neutrophil infiltration has been reported to play an important role in spinal cord injury (SCI). In addition to their cardioprotective effects, beta-blockers have been found to have neuroprotective effects on the central nervous system, but their effect on SCI has not yet been studied. In the current study, we investigated the effect of metoprolol on myeloperoxidase (MPO) activity, a marker of neutrophil activation, in the spinal cord after experimental SCI in rats. Rats were divided into six groups: controls received only laminectomy and spinal cord samples were taken immediately; the sham operated group received laminectomy, and spinal cord samples were taken 4h after laminectomy; the trauma only group underwent a 50g/cm contusion injury but received no medication; and three other groups underwent trauma as for the trauma group, and received 30mg/kg methylprednisolone, 1mg/kg metoprolol, or 1mL saline, respectively. All the medications were given intraperitoneally as single doses, immediately after trauma. Spinal cord samples were taken 4h after trauma and studied for MPO activity. The results showed that tissue MPO activity increased after injury. Both metoprolol and methylprednisolone treatments decreased MPO activity, indicating a reduction in neutrophil infiltration in damaged tissue. The effect of metoprolol on MPO activity was found to be similar to methylprednisolone. In view of these data, we conclude that metoprolol may be effective in protecting rat spinal cord from secondary injury.

Reducing the risks of sudden death and heart failure post myocardial infarction: utility of optimized pharmacotherapy

Current guidelines define the standard of care for patients after myocardial infarction (MI), with particular focus on patients with significant ventricular dysfunction. Inherent in these recommendations are assumptions about the relative risks and benefits, as well as the costs, of the available options. This review will consider strategies to prevent sudden death and heart failure post-MI by utilization of pharmacologic therapies--angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARB), aldosterone antagonists, statins, and beta-blockers--in parallel with the approaches reviewed elsewhere in this supplement. A patient-centric approach necessitates that drugs in each class be compared for efficacy within this patient population. Clinical trials have demonstrated the efficacy of several drugs, such as ACE inhibitors, beta-blockers, and aldosterone antagonists, in patients post-MI, yet these benefits do not seem to be reflected in the epidemiologic data. This may reflect underutilization of these therapies or, alternatively, support the notion that efficacy in clinical trials does not assure effectiveness in clinical practice. The latter point is a subject of ongoing investigation, while the former is being addressed through quality-of-care initiatives. In clinical practice, aggressiveness is key, starting with patient education. If patients understand their risks better, compliance and adoption of a more ideal lifestyle seem more likely. However, even with educational programs, human nature teaches us that marked change in behavior is difficult and therefore, to minimize risks, particularly of sudden death and heart failure post infarction, an optimized pharmacologic regimen serves as a powerful tool.

Carvedilol inhibits basal and stimulated ACE production in human endothelial cells

Angiotensin-converting enzyme (ACE) plays an important role in the pathophysiology of cardiovascular disease. We examined the effect of carvedilol, a cardiovascular drug, on basal and stimulated ACE production in human endothelial cells. Carvedilol (0.625-5 microM), in a concentration-dependent manner, inhibited basal and vascular endothelial growth factor (VEGF, 0.5 nM) or phorbol 12-myristate 13-acetate (PMA, 10 nM) induced ACE up-regulation. Carvedilol has non-selective beta-adrenoceptor and selective alpha1-adrenoceptor blocking activity, calcium channel blocking, and anti-oxidant activity. To study whether these activities were related to ACE down-regulation, endothelial cells were treated with metoprolol (1-10 microM), propranolol (1-10 microM), prazosin (1-5 microM), nicardipine (1-10 microM), probucol (1-100 microM), or ascorbic acid (1-100 microM). None of these compounds modified ACE. VEGF (0.5 nM) and PMA (10 nM) induced PKC phosphorylation, which was inhibited by co-treatment of cell cultures with carvedilol (5 microM). In conclusion, carvedilol inhibited basal and VEGF or PMA induced ACE up-regulation. Inhibition of PKC phosphorylation was probably involved in carvedilol action.

Carvedilol inhibits tumor necrosis factor-alpha-induced endothelial transcription factor activation, adhesion molecule expression, and adhesiveness to human mononuclear cells

OBJECTIVE

We tested the hypothesis that carvedilol, a beta-adrenoceptor and alpha-adrenoceptor antagonist with potent antioxidant property, could inhibit tumor necrosis factor-alpha (TNF-alpha)-induced endothelial adhesiveness to human mononuclear cells (MNCs), an early sign of atherogenesis.

METHODS AND RESULTS

Circulating MNCs were isolated from the peripheral blood of healthy subjects. Compared with control condition, pretreatment of carvedilol (10 micromol/L for 18 hours) or probucol (5 micromol/L for 18 hours), but not propanolol, prazosin, or both propanolol and prazosin significantly decreased TNF-alpha-stimulated adhesiveness of cultured human aortic endothelial cells (HAECs) to MNCs. Carvedilol inhibited TNF-alpha-stimulated endothelial vascular cell adhesion molecule-1 (VCAM-1) and E-selectin (66.0+/-2.0% and 55.60+/-1.0% of control, P<0.05, respectively) expression, whereas probucol inhibited only VCAM-1 expression (79.0+/-5.0% of control, P<0.05). Propanolol, prazosin, or both did not alter the expression of adhesion molecules. Further, pretreatment with carvedilol significantly inhibited TNF-alpha-stimulated intracellular reactive oxygen species (ROS) production and the activation of redox sensitive nuclear factor kappa B and activator protein-1 transcription pathways.

CONCLUSIONS

Carvedilol reduced TNF-alpha-stimulated endothelial adhesiveness to human MNCs by inhibiting intracellular ROS production, transcription factor activation, and VCAM-1 as well as E-selectin expression, suggesting its potential role in clinical atherosclerosis disease.

Effects of carvedilol on oxidative stress in polymorphonuclear and mononuclear cells in patients with essential hypertension

PURPOSE

To compare the effects of carvedilol and propranolol on oxidative stress in leukocytes and C-reactive protein levels in patients with hypertension.

METHODS

Sixty hypertensive patients were randomly assigned to carvedilol (20 mg; n = 30) or propranolol (60 mg; n = 30) for 6 months. Thirty normotensive subjects who were given placebo served as controls. Oxidative stress in polymorphonuclear cells and mononuclear cells were measured by gated flow cytometry. C-reactive protein levels were measured by immunonephelometric assay.

RESULTS

Oxidative stress in polymorphonuclear cells and mononuclear cells was increased significantly in hypertensive patients compared with in normotensive controls. After 6 months of treatment, carvedilol decreased oxidative stress significantly in polymorphonuclear cells by a mean of 45 arbitrary units (95% confidence interval [CI]: 32 to 59 arbitrary units; P <0.001) and propranolol decreased oxidative stress significantly by 20 arbitrary units (95% CI: 7 to 33 arbitrary units; P <0.003; P = 0.001 for difference between treatments). Carvedilol also decreased oxidative stress significantly in mononuclear cells by 23 arbitrary units (95% CI: 15 to 31 arbitrary units; P <0.001), whereas propranolol decreased oxidative stress by 2 arbitrary units (95% CI: 7 to 12 arbitrary units; P = 0.62; P = 0.002 for difference between treatments). Carvedilol decreased C-reactive protein levels significantly by a median of 0.073 mg/dL (interquartile range, 0.034 to 0.112 mg/dL; P <0.001), whereas propranolol decreased levels by 0.012 mg/dL (interquartile range, 0.009 to 0.032 mg/dL; P = 0.26; P = 0.003 for difference between treatments).

CONCLUSION

These findings suggest that carvedilol inhibits oxidative stress in polymorphonuclear and mononuclear cells, as well as lowers C-reactive protein levels, to a greater extent than does propranolol in hypertensive patients.

Carvedilol: a review of its use in chronic heart failure

Carvedilol (Dilatrend) blocks beta(1)-, beta(2)- and alpha(1)-adrenoceptors, and has antioxidant and antiproliferative effects. Carvedilol improved left ventricular ejection fraction (LVEF) in patients with chronic heart failure (CHF) in numerous studies. Moreover, significantly greater increases from baseline in LVEF were seen with carvedilol than with metoprolol in a double-blind, randomised study and in a meta-analysis. Carvedilol also reversed or attenuated left ventricular remodelling in patients with CHF and in those with left ventricular dysfunction after acute myocardial infarction (MI). Combined analysis of studies in the US Carvedilol Heart Failure Trials Program (patients had varying severities of CHF; n = 1094) revealed that mortality was significantly lower in carvedilol than in placebo recipients. In addition, the risk of hospitalisation for any cardiovascular cause was significantly lower with carvedilol than with placebo. Mortality was significantly lower with carvedilol than with metoprolol in patients with mild to severe CHF in the Carvedilol Or Metoprolol European Trial (COMET) [n = 3029]. The Carvedilol Prospective Randomised Cumulative Survival (COPERNICUS) trial (n = 2289) demonstrated that compared with placebo, carvedilol was associated with significant reductions in all-cause mortality and the combined endpoint of death or hospitalisation for any reason in severe CHF. All-cause mortality was reduced in patients who received carvedilol in addition to conventional therapy compared with those who received placebo plus conventional therapy in the Carvedilol Post-Infarct Survival Control in LV Dysfunction (CAPRICORN) trial (enrolling 1959 patients with left ventricular dysfunction following acute MI). Carvedilol was generally well tolerated in patients with CHF. Adverse events associated with the alpha- and beta-blocking effects of the drug occurred more commonly with carvedilol than with placebo, whereas placebo recipients were more likely to experience worsening heart failure. In conclusion, carvedilol blocks beta(1)-, beta(2)- and alpha(1)-adrenoceptors and has a unique pharmacological profile. It is thought that additional properties of carvedilol (e.g. antioxidant and antiproliferative effects) contribute to its beneficial effects in CHF. Carvedilol improves ventricular function and reduces mortality and morbidity in patients with mild to severe CHF, and should be considered a standard treatment option in this setting. Administering carvedilol in addition to conventional therapy reduces mortality and attenuates myocardial remodelling in patients with left ventricular dysfunction following acute MI. Moreover, mortality was significantly lower with carvedilol than with metoprolol in patients with mild to severe CHF, suggesting that carvedilol may be the preferred beta-blocker.

Oxidative stress in chronic renal allograft nephropathy in rats: effects of long-term treatment with carvedilol, BM 91.0228, or alpha-tocopherol

Oxidative stress is markedly increased after kidney transplantation and may participate in the development and/or progression of chronic renal allograft nephropathy. In the present study we sought to assess the nephroprotective potential of antioxidative treatment in renal allograft recipients. Experiments were performed in the Fisher-Lewis rat model of chronic renal allograft nephropathy, with isografted Lewis rats serving as controls. Allografted rats were orally treated with carvedilol, an antihypertensive drug with antioxidative properties (25 mg/kg/d), its purely antioxidative derivative BM 91.0228 (5 mg/kg/d), alpha-tocopherol (100 mg/kg/d), a combination of propranolol/doxazosine (10/5 mg/kg/d), or vehicle for 24 weeks. At the end of the study, oxidative status and influence of antioxidative treatment were assessed in transplanted animals. Chronic allograft nephropathy was characterized by a marked increase of markers for oxidative stress (increased plasma and kidney levels of malondialdehyde, reduced glutathione, and tocopherol levels in renal allografts). Treatment with carvedilol, BM 91.0228, and tocopherol significantly improved antioxidative status of allograft kidney recipients. In addition, carvedilol reduced elevated blood pressure in allografted rats. However none of the drugs had a beneficial influence on functional and morphologic renal changes. Our data thus demonstrate that long-term treatment with the antioxidants carvedilol, BM 91.0228, or alpha-tocopherol does not prevent development of chronic transplant nephropathy, despite an improvement of antioxidative status.

Different mechanisms of adhesion molecule expression in human dermal microvascular endothelial cells by xanthoma tissue-mediated and copper-mediated oxidized low density lipoproteins

BACKGROUND

Oxidation of low density lipoprotein (LDL) has been implicated in infiltration of foam cells derived from circulating monocytes. Monocyte adhesion to endothelial cells and migration into dermis are essential steps for infiltration of foam cells.

OBJECTIVE

We investigated the role of adhesion molecules contributing to the process of monocyte adhesion to human dermal microvascular endothelial cells (HDMEC). Special attention was paid to the signal transduction for adhesion molecule expression induced by two distinct types of oxidized LDL.

METHODS

HDMEC were incubated with xanthoma tissue-modified LDL (x-LDL), a model of extravasated LDL oxidized in xanthoma lesions, or Cu(2+)-treated LDL (Cu-LDL), a model of oxidized LDL. Adhesion of U937 cells, a human monocytic leukemia cell line, to HDMEC and expression of endothelial cell adhesion molecules on HDMEC were examined. Signal transduction pathways for the adhesion molecule expression were evaluated by employing specific inhibitors.

RESULTS

x-LDL induced adhesion of U937 cells to HDMEC through vascular cell adhesion molecule-1 (VCAM-1) and E-selectin by activating tyrosine kinase pathway. Cu-LDL up-regulated the adhesion through not only VCAM-1 and E-selectin but also intercellular cell adhesion molecule-1 (ICAM-1) by activating G(i) protein pathway.

CONCLUSION

Extravasated and oxidized LDL in xanthoma lesions contributes to foam cell recruitment by activating tyrosine kinase pathway and inducing adhesion of monocytes to HDMEC through VCAM-1 and E-selectin. Cu-LDL, on the other hand, activates G(i) protein pathway and induces the adhesion through ICAM-1, VCAM-1 and E-selectin.

Treatment of hypertension in renal transplant recipients

PURPOSE OF REVIEW

Hypertension is very common in renal transplant recipients and is a significant risk factor for mortality from cardiovascular diseases and for development of graft dysfunction.

RECENT FINDINGS

Recent guidelines for the treatment of hypertension (Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure VI Report and World Health Organization Guidelines) do not directly address post-transplant hypertension. Specific recommendations for the drug treatment of hypertension in renal allograft recipients have not been given in the Clinical Practice Guidelines of the American Society of Transplantation or those of the European Renal Association.

SUMMARY

The present paper summarizes some important aspects of post-transplant hypertension and discusses potential treatment strategies aimed at reducing blood pressure and thus improving patient and allograft survival.

[Analysis of differences in flow-mediated dilation in relation to the treatment of coronary patients]

INTRODUCTION

Flow-mediated dilation (FMD) is thought to be related to the development of coronary disease. We were interested in knowing the degree of FMD in a large sample of coronary patients in relation to the therapy they were given in clinical practice.

PATIENTS AND METHOD

We studied 1,081 coronary patients (age 68 +/- 12 years, 73% male) in which FMD was evaluated in the brachial artery. The patients were classified into 5 treatment groups (416 who receive 2 or more treatments were excluded): group A: 81 controls treated with aspirin, group B: 198 treated with ACE inhibitors, group C: 106 with calcium antagonists, group D: 145 with beta-blockers, and group E: 135 with lipid lowering medication (93% statins).

RESULTS

ANOVA was used to analyze the differences between groups. With regard to the number of risk factors present in each group, the patients treated with ACE inhibitors (2.44 +/- 0.79 vs 2.14 +/- 0.89; p < 0.05) and statins (3.45 +/- 0.70 vs 2.14 +/- 0.89; p < 0.05) had more risk factors than GrA and higher levels of LDL-cholesterol (ACE inhibitors 145.0 +/- 33.5 vs 128.5 +/- 32.2 and statins 157.8 +/- 45.3 vs 128.5 +/- 32.2; p < 0.05). GrB had a higher glycemia than controls (123.4 +/- 32.2 vs 114.7 +/- 33.7; p < 0.05). The control group was younger than the therapeutic groups (p < 0.05). Compared with the control group, FMD was significantly higher only in the group treated with ACE inhibitors (3.42 +/- 6.01 vs 0.82 +/- 6.04; p < 0.05). Multivariate logistical regression showed that treatment with ACE inhibitors and statins (p < 0.05) were independent predictors of FMD > 4%.

CONCLUSION

Treatment with ACE inhibitors or statins was predictive of the normalization of FMD in coronary patients in clinical practice.

Apoptosis in the ischemic reperfused myocardium

Recovery of the myocardium from an ischemic event depends on the reperfusion of the ischemic area. Resumed blood flow to the tissue restores the metabolic substrates necessary for energy production and cell survival. Paradoxically, ischemic reperfusion (I/R) can result in further damage to the myocardium (I/R injury) through an acute inflammatory response mediated by cytokines, neutrophils, macrophages, and reactive oxygen species. These events can trigger cardiomyocyte death through either necrosis or apoptosis. This report will focus on the apoptosis process, which is an organized, active, and gene-directed process of cell self-destruction that can be initiated by intracellular genetic programs, or second messenger pathways inside the cell upon extracellular stimulation by signaling molecules or stress. Awareness of the apoptotic process in cardiomyocytes and endothelial cells is relevant to myocardial preservation during cardiopulmonary bypass compared with off-pump cornary artery bypass procedures. Pharmacological interventions of the signaling pathways that control apoptosis provide an opportunity for new therapeutic approaches to reduce I/R injury in the heart. This review of apoptosis will introduce the perfusionist to apoptosis in the I/R heart, discuss some of the metabolic pathways that initiate it, and report on developing strategies to prevent it.

Role of beta blockers in congestive heart failure

Prolonged activation of the adrenergic nervous system has adverse consequences on the cardiovascular system in patients with congestive heart failure. Beta adrenergic receptor-blocker therapy modifies these deleterious effects. Beta blockers have been shown to improve myocardial function and survival when used in conjunction with conventional treatment with diuretics, angiotensin-converting enzyme inhibitors, and digoxin. Beta blocker therapy in mild-to-moderate heart failure should not be delayed because it causes some reversal of both neurohormonal compensatory mechanisms and the deleterious myocardial remodeling process. This paper reviews the beneficial effects of beta adrenergic receptor-blocker therapy on the pathophysiology, symptoms, left ventricular function, morbidity, and mortality in patients with congestive heart failure. (c)2000 by CHF, Inc.

Effect of gliclazide on monocyte-endothelium interactions in diabetes

Enhanced monocyte-endothelial cell interactions have been documented in diabetes. Because adherence of monocytes to the endothelium is one of the earliest events in the development of atherosclerosis, its alteration may represent one of the mechanisms leading to accelerated atherosclerosis in diabetic patients. Previous studies have suggested that lipoprotein oxidation and protein glycation may contribute to the increased monocyte binding to the diabetic vasculature. Based on the recent finding that gliclazide has free-radical scavenging activity, we examined the ex vivo and in vitro effects of this drug on human monocyte binding to endothelial cells. Our results demonstrate that short-term administration of gliclazide to patients with type 2 diabetes lowers the enhanced adhesion of diabetic monocytes observed before gliclazide treatment (163+/-24% over control values, p<0.005) to levels similar to those observed in controls. They also show that gliclazide (10 microg/ml) reduces in vitro by approximately 35% both oxidized low-density lipoprotein (LDL)- and glycated albumin-induced monocyte adhesion to endothelial cells. Based on these results, we next investigated the molecular mechanisms responsible for the inhibitory effect of gliclazide on glycated albumin-induced monocyte adhesion to endothelium. In glycated albumin-treated endothelial cells, we observed induction of cell-associated expression of E-selectin (ELAM-1; 170+/-10% over control values, p<0.005), intercellular cell adhesion molecule-1 (ICAM-1; 131+/-8% over control values, p<0.005) and vascular cell adhesion molecule-1 (VCAM-1; 134+/-8% over control values, p<0.005), augmentation in the levels of the transcripts of these molecules, and an increase in the DNA binding of NF-kappaB in the promoters of these antigens. Gliclazide markedly inhibited the induction of all these parameters. Because the oxidative stress-sensitive transcription factor NF-kappaB is implicated in endothelial cell activation, the observed inhibitory effect of gliclazide on NF-kappaB activation and glycated albumin-induced expression of DNA binding activity for the NF-kappaB site in the ELAM-1, ICAM-1 and VCAM-1 promoters seems to be due to its antioxidant properties. These results suggest that gliclazide, by its ability to reduce endothelial activation, may exert potential beneficial effects in the prevention of atherosclerosis associated with type 2 diabetes.

No effect of carvedilol on nitric oxide generation in phagocytes but modulation of production of superoxide ions

Since carvedilol has been claimed to possess antioxidative effects, this drug might affect functional responses, including nitric oxide (NO) generation, of polymorphonuclear neutrophils (PMN) and macrophages. When we assessed the effects of carvedilol on PMN responses in vitro, we observed that carvedilol dose dependently modulated generation of superoxide ions by NADPH oxidase when induced by the formylpeptide formyl-methionyl-leucyl-phenylalanine (fMLP) or the phorbol ester phorbol myristate acetate. This effect was not coupled to diminished phospholipase C activity. In contrast to the effect on NADPH oxidase, neither the fMLP-elicited NO generation by PMN nor the response of the murine macrophage cell line J774 to lipopolysaccharide was affected. There was no evidence from cell-free assay systems that carvedilol is a scavenger for superoxide ions or NO. Moreover, carvedilol did not affect other reactions dependent on NO, e.g. spontaneous or fMLP-stimulated PMN migration or lipoxin A(4)-, fMLP-, or A23187-induced neutrophil cytotoxicity for human umbilical vein endothelial cells. Thus, these effects point to the possibility that carvedilol modulates the NADPH oxidase of PMN but leaves the nitric oxide synthase of phagocytes intact.

The inhibitory effects of carvedilol against arrhythmias induced by coronary reperfusion in anesthetized rats

BACKGROUND

Previous study has shown the antiarrhythmic effects of carvedilol on isolated rat hearts, but little is known about the mechanism of this protective action. This article examines the inhibitory effect of carvedilol against arrhythmias induced by reperfusion in anesthetized rats. In addition, the results are compared with those with propranolol, superoxide dismutase (SOD) plus catalase, and a combination of both in order to elucidate the mechanism of the protective actions.

METHODS AND MATERIALS

Ninety percent of the rats in the control group showed lethal ventricular fibrillation (VF). Carvedilol at the doses of 0.03, 0.1, and 0.3 mg/kg significantly reduced the incidence of lethal VF to 0%, 0%, and 10%, respectively (P <.05). In contrast, propranolol at the doses of 0.3, 1.0, and 3.0 mg/kg and SOD (35,000 units/kg) plus catalase (400,000 units/kg) did not reduce the incidence of lethal VF (80%, 60%, 70%, and 70%, respectively). However, administration of a combination of propranolol (1.0 mg/kg) and SOD plus catalase completely inhibited the occurrence of lethal VF to 0% (P<.05).

CONCLUSION

These results indicate that carvedilol has the inhibitory effect against reperfusion arrhythmias in rats and suggest that the mechanism of action of this compound is related to the combined effects of beta-blocking and antioxidant.

Endothelial apoptosis: could it have a role in the pathogenesis and treatment of disease?

Endothelial apoptosis can be found in a number of diseases. This review summarizes the current knowledge about the causes and consequences of endothelial apoptosis, and analyzes its possible role in the pathogenesis and treatment of several diseases. Novel forms of therapy based on the proposed pathophysiologic mechanisms are discussed.

Gliclazide decreases low-density lipoprotein oxidation and monocyte adhesion to the endothelium

Increasing evidence implicates oxidized low-density lipoprotein (LDL) and advanced glycation end products (AGE) in the atherogenesis associated with diabetes mellitus. In the present study, we examined the in vitro effects of gliclazide on LDL oxidation and monocyte adhesion to endothelial cells induced by oxidized LDL and glycated albumin. To assess the clinical relevance of our in vitro findings, we also measured the effect on monocyte adhesion of gliclazide administration to type 2 diabetic patients. Incubation of human monocytes and endothelial cells with increasing concentrations of gliclazide (0 to 10 microg/mL) and native LDL (100 microg/mL) induced a dose-dependent diminution of cell-mediated LDL oxidation. Pretreatment of endothelial cells with gliclazide (0 to 10 microg/mL) before addition of native LDL (100 microg/mL) or glycated albumin (100 microg/mL) resulted in a dose-dependent diminution of oxidized LDL- and glycated albumin-induced monocyte adhesion to endothelial cells. In type 2 diabetic patients, administration of gliclazide inhibits the increased adhesiveness of monocytes to levels similar to those observed in control subjects. These results indicate that gliclazide is an antioxidant and suggest a beneficial effect of this drug in the prevention of atherosclerosis associated with type 2 diabetes.

Carvedilol treatment of kidney graft recipients with chronic rejection

Carvedilol is an antihypertensive drug with properties that may be potentially beneficial for kidney graft recipients. The purpose of the study was to investigate if progression of an established chronic rejection may be attenuated or reversed by carvedilol. An open, single-centre, phase II, pilot study, with a 2-yr follow-up, was performed in 25 kidney graft recipients with chronic rejection or accelerated transplant atherosclerosis. Seventeen patients had stable graft function assessed by serum creatinine levels. Eight patients withdrew from the study due to lack of efficacy (increase in serum creatinine 174-477 micromol/L (46-191%) from the initial levels). However. these patients had higher serum creatinine levels and proteinuria already at the start of the study. Both systolic and diastolic blood pressure, as well as heart rate, were stable in all study patients. Low density lipoprotein (LDL)/high density lipoprotein (HDL) cholesterol ratio decreased from 4.7 +/- 1.9 at 1 month to 3.5 +/- 1.2 at 18 months (p < 0.05), and MDA plasma levels decreased from 0.714 +/- 0.119 to 0.493 +/- 0.073 micromol/L after 3 months of carvedilol treatment (p < 0.05). No attenuation of progression of chronic graft rejection by carvedilol treatment was observed in the study. It is suggested that the process of chronic rejection could not be reversed by carvedilol because the patients included in the study already had severe morphological and functional changes of the graft. In conclusion, our study demonstrated that carvedilol provides a good control of blood pressure in renal transplanted patients. Carvedilol treatment had a beneficial effect on lipid pattern and reduced lipid oxidation, but there was no obvious effect on progression of chronic rejection.

Oxidized low density lipoprotein: atherogenic and proinflammatory characteristics during macrophage foam cell formation. An inhibitory role for nutritional antioxidants and serum paraoxonase

Oxidative stress and inflammatory processes are of major importance in atherogenesis because they stimulate oxidized LDL (Ox-LDL)-induced macrophage cholesterol accumulation and foam cell formation, the hallmark of early atherosclerosis. Under oxidative stress, both blood monocytes and plasma lipoproteins invade the arterial wall, where they are exposed to atherogenic modifications. Oxidative stress stimulates endothelial secretion of monocyte chemoattractant protein 1 (MCP-1) and of macrophage colony stimulating factor (M-CSF), leading to monocyte adhesion and differentiation, respectively. LDL binds to extracellular matrix (ECM secreted by endothelial cells, smooth muscle cells and macrophages) proteoglycans, in a process that contributes to the enhanced susceptibility of the lipoprotein to oxidation by arterial wall macrophages. ECM-retained Ox-LDL is taken up by activated macrophages via their scavenger receptors. This leads to cellular cholesterol accumulation and enhanced atherogenesis. Protection of LDL against oxidation by antioxidants that can act directly on the LDL, or indirectly on the cellular oxidative machinery, or conversion of Ox-LDL to a non-atherogenic particle by HDL-associated paraoxonase (PON-1), can contribute to attenuation of atherosclerosis.

Comparative effects of carvedilol and metoprolol on cardiac ischemia-reperfusion injury

The effects of carvedilol, a multiple-action neurohormonal antagonist, and metoprolol, a highly selective beta1 antagonist, were compared on postischemic contractile recovery and contracture. Isolated rabbit hearts were aerobically perfused for 45 min and subjected to zero-flow normothermic ischemia for 30 or 60 min followed by reperfusion for 30 min. Carvedilol and metoprolol were added to the perfusion solution 10 min before inducing ischemia and were maintained in the perfusate throughout reperfusion. Left ventricular developed pressure (LVDP) and left ventricular end-diastolic pressure (LVEDP) were assessed with an intraventricular balloon. Because the volume of the balloon was held constant, an increase in LVEDP reflected an increase in diastolic chamber stiffness or "contracture." After 30 min of ischemia, the carvedilol-treated hearts exhibited a significantly better cardiac function than did control or metoprolol-treated hearts. At the end of reperfusion, the control group LVDP recovered to 21.4+/-9.9% of the preischemic value. With 0.03, 0.1, and 0.3 microM metoprolol, LVDP recovered to 33.2+/-13.6%, 41.7+/-13.0%, and 48.8+/-13.3% of initial developed pressure, respectively. In the carvedilol group, a greater recovery of LVDP was obtained at 0.03, 0.1, and 0.3 microM: 64.0+/-2.5%, 60.4+/-6.3%, and 68.0+/-2.0% of preischemic values, respectively (p < 0.05 vs. controls). Within the first 5 min of reperfusion, LVEDP increased to 70.3+/-2.7 mm Hg in control hearts, indicating a pronounced contracture, whereas metoprolol reduced LVEDP when given at high concentration, 0.3 microM (41.9+/-10.7 mm Hg). Carvedilol, even at the lowest concentration, 0.03 microM, almost completely inhibited the postischemic contracture (16.5+/-4.0 mm Hg; p < 0.05 vs. control and metoprolol). The cardioprotection provided by carvedilol also is observed in hearts subjected to more severe ischemic periods. After 60 min of ischemia, control hearts failed to restore LVDP function; in the metoprolol group, ventricular function recovered to only 4.6+/-3.1%, whereas carvedilol-treated hearts exhibited 23.6+/-1.9% of preischemic values at the end of reperfusion. In addition, carvedilol induced a reduction in ischemic contracture: control, 36.7+/-3 mm Hg; metoprolol, 38.7+/-3.7 mm Hg; and carvedilol, 15.7+/-8.4 mm Hg at 50 min of ischemia. Similarly, carvedilol reduced contracture during the reperfusion compared with metoprolol and control groups (83.2+/-3.4 mm Hg, 106.9+/-3.3 mm Hg, and 107.6+/-4.1 mm Hg, respectively). These data clearly demonstrate that carvedilol was markedly more effective than metoprolol to protect systolic function after ischemia and to reduce postischemic contracture.

Protective effects of carvedilol in the myocardium

Beta blockers have long been used in the treatment of systemic hypertension, where they effectively lower blood pressure and, in so doing, they decrease left ventricular hypertrophy. The sympathetic nervous system is activated in patients with congestive heart failure, and therefore it is logical that beta blockers may also provide benefit in these patients. As such, beta blockers are currently being evaluated in several large clinical trials in congestive heart failure. One particular drug, carvedilol, is a third-generation vasodilating beta blocker that is marketed for the treatment of hypertension. The drug lowers systemic arterial blood pressure without producing reflex tachycardia and preserves renal function. Carvedilol decreases mortality by 65% and decreases hospitalization by 29% in patients with congestive heart failure. The effects of carvedilol in heart failure may result, at least in part, from beta blockade as well as vasodilation, the latter resulting from alpha(1)-adrenoceptor blockade. Interestingly, carvedilol has a number of additional properties that may also provide benefit in these patients. Carvedilol and several of its metabolites are potent antioxidants that may inhibit catecholamine toxicity resulting from the oxidation of norepinephrine and the subsequent formation of toxic intermediates, including the generation of reactive oxygen free radicals in the myocardium. As a result of its antioxidant activity, carvedilol also blocks the expression of several genes involved in myocardial damage and cardiac remodeling, and the drug inhibits free radical-induced activation of transcription factors and programmed cell death (apoptosis). Carvedilol is a novel beta blocker that is highly effective in the treatment of hypertension and congestive heart failure, and combines in one molecule a number of important pharmacologic properties.

Gliclazide decreases cell-mediated low-density lipoprotein (LDL) oxidation and reduces monocyte adhesion to endothelial cells induced by oxidatively modified LDL

Low-density lipoprotein (LDL) oxidation has been suggested to play a key role in the pathogenesis of atherosclerosis, a major complication of diabetes mellitus. Gliclazide, a second-generation sulfonylurea, is widely used in the treatment of type II diabetes mellitus. Recently, a free-radical-scavenging activity of gliclazide has been reported. In the present study, we examined the effects of gliclazide on cell-mediated LDL oxidation and monocyte adhesion to endothelial cells induced by oxidatively modified LDL. Incubation of human monocytes and bovine aortic endothelial cells (BAE cells) with increasing concentrations of gliclazide (0 to 10 micrograms/mL) and native LDL (100 micrograms/mL) resulted in a dose-dependent diminution of cell-mediated LDL oxidation as assayed by measurement of thiobarbituric acid (TBA)-reactive substances (TBARS). In addition, exposure of BAE cells to gliclazide (0 to 10 micrograms/mL) and native LDL (100 micrograms/mL) induced a dose-dependent diminution of the oxidized LDL-induced monocyte adhesion to BAE cells as measured by the myeloperoxidase (MPO) assay. The effects of glyburide, another second-generation sulfonylurea, were also tested on cell-mediated oxidation of LDL and LDL-induced monocyte adhesion to the endothelium. No significant effect of this drug was observed on these two processes. These results therefore demonstrate that gliclazide is effective in vitro in reducing both cell-mediated LDL oxidation and monocyte adhesion to the endothelium. These findings suggest a potential beneficial effect of gliclazide in the prevention of atherosclerosis in diabetic patients.

Amyloid beta-induced neurotoxicity is associated with phospholipase D activation in cultured rat hippocampal cells

The role of phospholipase D (PLD) in amyloid beta (Abeta)-induced neurotoxicity was studied by comparing the effects of Abeta (1-40) on PLD activity and release of lactate dehydrogenase (LDH) from cultured rat hippocampal cells. PLD activity was determined in [3H]myristic acid-labeled cells by measuring the formation of [3H]phosphatidylethanol in the presence of ethanol (0.5%), and LDH activity in the cell media was measured via colorimetric assay. Abeta (50 microM), aged for 3 days to allow for peptide aggregation, acutely (1 h) stimulated PLD activity. Unaged Abeta (50 microM) had no acute (1 h) effect on PLD activity, but significantly stimulated PLD activity by 87% when incubated with cells for 1-3 days. Abeta (50 microM)-induced PLD activity was closely correlated with Abeta (50 microM)-induced LDH release over a time course of 1-3 days. These data suggest that PLD activation may be involved in Abeta-induced neurotoxicity.

Are the reactive oxygen-derived species (ROS) interactive properties of the many therapeutic drugs from various categories pertinent to their beneficial effects?

Many pathologic states are known to involve the generation of reactive oxygen species, (ROS). It is not known at present to what extent these phenomena are due to ROS formation, or if their formation is a result of the disease. Many therapeutic drugs either scavenge ROS or inhibit their formation. The purpose of this review is to match the drugs used for certain diseases with their anti-ROS actions. This attempted correlation is made to try to give an answer to the title question.