Sabine C. Wolf

Effects of nebivolol on proliferation and apoptosis of human coronary artery smooth muscle and endothelial cells

OBJECTIVE Secondary failure due to late restenosis continues to occur in 30-50% of individuals after PTCA. beta-Blockers play an important role in the treatment of CAD. The aim of this study was to investigate the effects of the new beta-blocker nebivolol on cell proliferation of human coronary smooth muscle cells (haCSMCs) and endothelial cells (haECs) in comparison to traditional beta-blockers. METHODS The effect of nebivolol and other beta-blockers on proliferation of HaECs and HaCSMCs was analyzed by bromodeoxyuridine incorporation. Apoptosis was measured by determination of hypodiploid DNA in both cell types. Additionally, in HaECs NO formation, endothelin-1 transcription and secretion were determined. RESULTS Incubation for 1, 2, 4, 7 or 14 days resulted in a concentration- and time-dependent reduction of proliferation up to 80% in HaECs and HaCSMCs. beta-Blockers such as propranolol, metoprolol or bisoprolol did not exert this effect. Nebivolol inhibited accelerated haCSMC proliferation even in the presence of growth factors such as TGFbeta(1) and PDGF-BB. Nebivolol concentration-dependently induced a moderate apoptosis (10(-5) mol/l: 23%) and a decrease of haCSMCs in the S-phase by 66%. HaECs showed comparable results. During nebivolol incubation NO formation of HaCEs increased, while endothelin-1 transcription and secretion were suppressed. CONCLUSION Whereas classical beta-blockers do not affect cell growth, only nebivolol inhibits haCSMC or haEC proliferation and induces a moderate rate of apoptosis. Furthermore, in HaCEs NO formation increases and endothelin-1 secretion decreases suggesting that nebivolol may represent a beta-blocker with great promises in CAD therapy.

β-blockers of the Third Generation Inhibit Endothelin-1 Liberation, mrna Production and Proliferation of Human Coronary Smooth Muscle and Endothelial Cells

tinues to occur in 30–50% of individuals (1). Restenosis after vascular injury probably results from the interdependent actions of the ensuing thrombosis, inflammation, liberation of potent growth-regulatory molecules such as platelet-derived growth factor, basic fibroblast growth factor, and smooth muscle cell accumulation (2). This involves proliferation, chemotactic migration into the intimal layers of the vessel and secretion of extracellular matrix proteins (3,4). Novel therapeutic strategies to treat cardiovascular disease should achieve four things: (1) improve prognosis in patients; (2) modulate thrombosis and inflammation; (3) reverse endothelial cell dysfunction; (4) inhibit vascular smooth muscle cell proliferation and migration. Because β-blockers improve the prognosis of postinfarct patients suffering from coronary heart disease, the aim of this study was to investigate the antiproliferative effect of the third generation β-blocker nebivolol. METHODS

Influence of Nebivolol and Metoprolol on Inflammatory Mediators in Human Coronary Endothelial or Smooth Muscle Cells. Effects on Neointima Formation After Balloon Denudation in Carotid Arteries of Rats Treated with Nebivolol

Objective and Background: Inflammation plays a critical role in all stages of atherogenesis. Proliferating vascular smooth muscle cells (SMC) and endothelial cells (EC) enhancing the inflammatory response, both contribute to the progression of atherosclerosis. Anti-proliferative, anti-inflammatory and anti-oxidative therapy seems to be a promising therapeutic strategy. The aim of this study was to assess the anti-proliferative and anti-inflammatory effect of the β-blocker nebivolol in comparison to metoprolol in vitro and to find out whether nebivolol inhibits neointima formation in vivo. Methods and Results: Real-time-RT-PCR revealed a decrease in VCAM-1, ICAM-1, PDGF-B, E-selectin and P-selectin mRNA expression in human coronary artery EC and SMC incubated with nebivolol for 72 hours while metoprolol did not have this effect. Nebivolol reduced MCP-1 and PDGF-BB protein in the culture supernatant of SMC and EC, respectively. Sprague-Dawley rats were treated with nebivolol for 0 or 35 days before and 28 days after carotid balloon injury. Immunohistological analyses showed that pre-treatment with nebivolol was associated with a decreased number of SMC layers and macrophages and an increased lumen area at the site of the arterial injury. The intima area was reduced by 43% after pre-treatment. Conclusion: We found that nebivolol reduced the expression of proinflammatory genes in endothelial cells and vascular smooth muscle cells in vitro whereas metoprolol did not. In vivo, nebivolol inhibited neointima formation by reducing SMC proliferation and macrophage accumulation.

Effect of nebivolol on left ventricular function in patients with chronic heart failure: a pilot study

Sympathetic activity is a significant predictor of a poor prognosis in heart failure. Beta‐blockers have been shown to improve the prognosis of patients with heart failure.

Chronically Elevated Endothelin-1 Concentrations Modulate the β-Adrenergic Receptor System In Vitro and In Vivo

In atherosclerosis and heart failure chronically elevated endothelin-1 (ET-1) plasma concentrations have been found which correlate with an increased mortality. The aim of this study was to determine the effects of chronically elevated ET-1 concentrations in vitro on the expression of the beta-adrenergic receptor (betaAR), the alpha-subunit of the stimulatory guanine-nucleotide-binding protein (G(s alpha)), and to determine betaARs ability to activate adenylyl cyclase. In order to elucidate the effects of elevated ET-1 concentrations in vivo, male rats were infused with ET-1 and betaAR density was measured. Smooth muscle cells were incubated with ET-1 (10(-7) mol/l) for 6 to 48 h. Densities of betaARs were determined by radioligand binding studies and the G(s alpha) was analyzed by Western blotting. Isoproterenol-mediated adenylyl cyclase activity was measured. Additionally male rats were infused with ET-1 for 3 weeks. In vitro the betaAR density increased by 52% (p < 0.05, n = 5). The G(s alpha) increased to 260%. The isoproterenol-stimulated adenylyl cyclase activity was increased to 228%. In vivo, the pulmonary and myocardial betaAR density was elevated by 43% and 97%, respectively. Chronic ET receptor activation induces a transregulation of betaARs in vitro and in vivo.

Endothelin-receptor antagonists in uremic cardiomyopathy.

Increased endothelin-1 (ET-1) levels were found in patients with chronic renal failure. These correlate with the severity of renal failure. Patients with elevated ET-1 concentrations show an increased cardiovascular mortality. The prevalence of severe left ventricular hypertrophy (LVH) is a very important factor for survival and morbidity in uremic patients The aim of this study was to assess the protective effect of ET-receptor antagonists in chronic uremia. Sprague Dawley rats were subtotally nephrectomized (SNX) and treated either with the endothelin-A- (ET(A)) receptor antagonist LU302146 or with the unselective ET(A)/ET(B)-receptor antagonist LU302872 (30 mg/kgbw/day both). After subtotal nephrectomy protein excretion SNX (130.0 +/- 22.5 mg/24 h) was increased in comparison to the ET(A)-group (446 +/- 103 mg/24 h) and the ET(AB)-group (23.2 +/- 37 mg/24 h) vs sham: 115 +/- 19 mg/24 h). Heart weight was decreased by the ET(A)/ET(B)-receptor antagonist LU302146. Left ventricular contractility was impaired in SNX by about 40%. Treatment with the ET-receptor antagonists prevented the impairment in left ventricular function. Our study results provide a possible therapeutic approach using ET receptor antagonists to reduce cardiac hypertrophy and renal proteinuria. Further human studies are needed to show whether this protection of the heart and kidney might influence the survival and life-expectancy of patients suffering from chronic renal failure.

Influence of endothelin receptor antagonists on myocardial protein kinase C isoforms in uraemic cardiomyopathy

Increased endothelin-1 (ET-1) levels were found in patients with chronic renal failure and these correlate with the severity of renal failure. Increased mortality due to cardiovascular problems is observed in patients with elevated ET-1 concentrations. The aim of this study was to find out the influence of ET-1 and ET receptor antagonists on myocardial protein kinase C (PKC) regulation in uraemic cardiomyopathy. Male rats were subtotally nephrectomized and treated with an ET(A)-receptor antagonist (30 mg x kg(-1) x day(-1), LU302146) or an ET(AB)-receptor antagonist (30 mg x kg(-1) x day(-1), LU302872) for 12 weeks. One group was left untreated (SNX) and one group was sham-operated (sham). Systolic blood pressure, myocardial weight and the changes of the protein kinase C isoforms in the heart were determined. PKC isoforms alpha and delta were investigated by Western blot analysis using specific antibodies. In the SNX group, systolic blood pressure rose to 154+/-5 mmHg after 12 weeks. The ET(A) receptor antagonist prevented this increase in blood pressure, but ET(AB) antagonism did not. Left ventricular weight increased in SNX; this increase was inhibited by the ET(A) receptor antagonist. In comparison with the sham group, PKC isoform alpha increased by 19% in SNX animals. When the SNX animals were treated with ET(A) or ET(AB) antagonists, PKC isoform alpha levels decreased by 31%. PKC isoform delta levels decreased by 35% in SNX animals. Treatment with both ET(A) or ET(AB) antagonists increased PKC isoform delta levels to normal. In the myocardium of uraemic rats PKC isoforms are differentially regulated with an increase in alpha isoform but a decrease in delta isoform. ET receptor blockers normalize these PKC isoforms.

Endothelin-1 and endothelin-3 levels in different types of glomerulonephritis

There is evidence that an activated renal endothelin (ET) system is involved in development of glomerulosclerosis. However it is still unknown if different ETs are involved in the pathogenesis of various types of glomerulonephritis (GN). This study characterized ET-1 and ET-3 levels in patients suffering from chronic GN. We performed a prospective study to evaluate the ET-1 and ET-3 levels in 19 patients with biopsy-proven GN, including four minimal-change nephropathies (MCN), six perimembraneous GN (PM-GN), and nine mesangioproliferative GN (MP-GN). Twelve healthy subjects matched for age and sex served as controls. ET-1 and ET-3 were measured in plasma (p) and in urine [spontaneous urine (sp.urine) and urine over 24 h (24-h urine)] using a specific radioimmunoassay. Patients and controls were compared using the Wilcoxon rank-sum test. In MCN, ET-1 levels were enhanced in sp. urine (p = 0.03) and 24-h urine (p = 0.01), whereas ET-3 levels did not differ from controls. In comparison, in PM-GN we found an increased ET-3 level in 24-h urine (p = 0.004). In MP-GN, ET-3 levels were also elevated in p (p = 0.0002) and urine specimens (sp. urine p = 0.05; 24-h urine p = 0.03). No positive correlation to C3 or C4 complement fractions was found. Age, blood pressure or renal function did not correlate with ET-1 or ET-3 levels. In MP-GN and PM-GN, ET-3 is elevated whereas ET-1 is not. In contrast ET-1 is increased in MC-GN. These data indicate an important role for the ET-1 and ET-3 systems in the pathophysiology of different forms of GN. This is significant with regard to an early preservation of renal function at the onset of GN by the use of selective ET antagonists.

Infectious risk factors for atherosclerotic vascular disease in hemodialysis patients-Chlamydia pneumoniae but not Helicobacter pylori or cytomegalovirus is associated with increased C-reactive protein

Background: Cardiovascular disease is a major problem in patients with chronic renal failure leading to increased mortality. Several infectious agents have been implicated to be associated with atherosclerosis. We were interested to evaluate whether there is a correlation between a past infection with Chlamydia pneumoniae (Cpn), Helicobacter pylori (Hp) or cytomegalovirus (CMV) and the manifestation of a symptomatic atherosclerotic disease in patients with endstage renal failure. Methods and Results: Patients (n = 267) on hemodialysis were investigated. In 101 patients with an apparent atherosclerotic disease (case group) increased IgA levels against Cpn were found (p ≤ 0.0001 vs. controls; n = 33). Nearly 45% of the case group had a history of myocardial infarction (MI) (p ≤ 0.0001). Prior stroke was found in about 30% of patients in the case group (p ≤ 0.002). Elevated CRP levels were identified as an independent risk factor for atherosclerosis in all groups. IgA seropositivity against Cpn correlated with elevated CRP values for all atherosclerotic patients (p ≤ 0.001), especially in the group of patients with MI (p ≤ 0.019) and peripheral vascular disease (p ≤ 0.005). There was no correlation between CMV (IgG, IgM) or Hp (IgA, IgG) seropositivity and atherosclerotic disease. Conclusion, IgA seropositivity for Cpn and elevated CRP values but not Hp or CMV was associated with an increased rate of symptomatic atherosclerotic manifestations as MI, stroke, cerebral or peripheral atherosclerosis in patients with endstage renal disease on hemodialysis.

Secondary syphilis after liver transplantation: case report and review of the literature

Abstract:  Syphilitic disease is uncommon, but its incidence has increased worldwide in the last few years. An unusual manifestation of secondary syphilis after orthotopic liver transplantation is described which confirms that lues should be considered in patients with immune deficiency and abnormal liver function tests.