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Biomedical subjects

Christoph Wanner

Publications and source records attributed to Christoph Wanner.

At least 19 recordsLinked to original sources
PubMed2007

Lipid metabolism in chronic kidney disease: the role of statins in cardiovascular risk.

In the general population, the relation between lipids and cardiovascular disease is clearcut, whereas it is highly controversial in chronic kidney disease (CKD) patients. This is primarily due to diverging results of retrospective observational trials. This study design often encounters confounding, especially in renal disease patients. Even if analyses are corrected for multiple influences, there might be unknown confounders changing the results. Prospective randomized trials assure that groups are comparable except for the intervention used. Confounding is eliminated by randomization. Nevertheless, the lipid discussion was restarted when two randomized, placebo-controlled, interventional trials on lipid-lowering therapy in renal patients have been published (Assessment of Lescol in Renal Transplantation and 4D Study [Atorvastatin in patients with type 2 diabetes on hemodialysis]). Surprisingly, both showed no significant reduction of the primary endpoint by statin therapy. In addition to other factors, this might be due to an altered pathogenesis of atherosclerosis in renal patients where multiple nontraditional cardiovascular risk factors are to be mentioned and different characteristics of cardiovascular disease with a high proportion of sudden cardiac death are present. This review will focus on dyslipidemia in renal failure and its treatment. The data published so far is summarized and grouped according to the different stages of CKD.

Cardiovascular Diseases↗
PubMed2006

Vasopeptidase inhibition normalizes blood pressure and restores endothelial function in renovascular hypertension.

BACKGROUND/AIMS: Vasopeptidase inhibitors by definition inhibit both angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP), therefore they may exceed the effect of ACE inhibitors in the treatment of hypertension. The present study investigated the effect of the vasopeptidase inhibitor AVE7688 in comparison to the ACE inhibitor ramipril on systolic blood pressure (SBP) and endothelial function in renovascular hypertension. METHODS: Wistar-Kyoto rats with renovascular hypertension (two-kidney one-clamp-model) were randomized 2 weeks after unilateral clamping of the right renal artery for 3 weeks' oral treatment with either AVE7688 (30 mg/kg/day), ramipril (1 mg/kg/day) or placebo. SBP was measured by the tail-cuff method and endothelium-dependent and -independent vascular function was assessed in isolated preconstricted (norepinephrine 10(-7) mol/l) aortic rings as relaxation to acetylcholine (10(-10)-10(-4) mol/l) and sodium nitroprusside (10(-10)-10(-4) mol/l), respectively. RESULTS: Two weeks after clamping, SBP was significantly elevated (196 +/- 16 vs. 145 +/- 8 mm Hg for sham-operated rats; p < 0.01) and further increased in placebo-treated animals to 208 +/- 19 mm Hg. Treatment with AVE7688 and ramipril had a similar blood pressure-lowering effect (119 +/- 8 and 124 +/- 10 mm Hg, respectively; p < 0.01 vs. placebo). Maximum endothelium-dependent relaxation was reduced in hypertensive rats (72 +/- 6 vs. 99 +/- 7% in control rats; p < 0.05). Endothelium-dependent relaxation was restored by AVE7688 (101 +/- 6%) and ramipril (94 +/- 8%), respectively, whereas endothelium-independent relaxation was comparable in all groups. CONCLUSION: In renovascular hypertension the vasopeptidase inhibitor AVE7688 exhibited similar blood pressure-lowering and endothelial protective properties as compared to the ACE inhibitor ramipril. Therefore, in high renin models of hypertension, vasopeptidase inhibition may be considered an alternative treatment option to ACE inhibition.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

Effects of pravastatin treatment on blood pressure regulation after renal transplantation.

BACKGROUND/AIM: Hypertension is one of the main cardiovascular risk factors and has an impact also on long-term kidney graft survival. In addition to their lipid-lowering properties, it was shown that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors also have a blood pressure lowering effect. We examined whether treatment with a statin interferes with blood pressure regulation and antihypertensive treatment after renal transplantation. METHODS: 74 patients were treated with initially 20 mg of pravastatin daily immediately after kidney transplantation. This group was compared to a matched cohort of 76 patients without statin treatment. All patients received standard immunosuppressive triple therapy with ciclosporin A microemulsion together with an antiproliferative agent and prednisolone. Primary objective of this analysis was systolic and diastolic blood pressure regulation with and without pravastatin. Furthermore, graft function expressed as creatinine clearance and proteinuria, immunosuppressive regimen, and incidence of cardiovascular events and graft loss were recorded for 48 months. RESULTS: The blood pressure regulation was comparable in both groups; however, to achieve this, significantly more antihypertensive drugs had to be used in the statin-treated patients as compared with the controls (2.9 vs. 2.2 agents at 48 months). A slightly higher ciclosporin A exposure of the statin-treated patients could have contributed to this observation. The graft function after 4 years was comparable between the groups (creatinine clearance 56.9 vs. 57.0 ml/min), and a trend of reduced proteinuria could be demonstrated after 4 years of statin treatment (0.4 vs. 0.9 g/day). The low-density lipoprotein cholesterol levels decreased as expected during treatment (3.1 vs. 3.7 mmol/l at 48 months), but the recommended target levels for patients with a high cardiovascular risk have not been reached. A trend towards lower incidences of acute rejection, chronic allograft nephropathy, and graft loss was noted in the statin-treated group. Adverse effects of statin treatment have not been observed. CONCLUSION: Treatment with pravastatin at low to average dosages does not result in improved blood pressure regulation after kidney transplantation.

Blood Pressure↗
PubMed2006

Effects of a polyelectrolyte additive on the selective dialysis membrane permeability for low-molecular-weight proteins.

BACKGROUND: Improving the sieving characteristics of dialysis membranes enhances the clearance of low-molecular-weight (LMW) proteins and may have an impact on outcome in patients receiving haemodialysis. To approach this goal, a novel polyelectrolyte additive process was applied to a polyethersulphone (PES) membrane. METHODS: Polyelectrolyte-modified PES was characterized in vitro by measuring complement activation and sieving coefficients of cytochrome c and serum albumin. In a prospective, randomized, cross-over study, instantaneous plasma water clearances and reduction rates of LMW proteins [beta(2)-microglobulin (b2m), cystatin c, myoglobin, retinol binding protein] were determined in eight patients receiving dialysis treatment with PES in comparison with polysulphone (PSU). Biocompatibility was assessed by determination of transient leucopenia, plasma levels of complement C5a, thrombin-antithrombin III (TAT), myeloperoxidase (MPO) and elastase (ELT). RESULTS: PES showed a steeper sieving profile and lower complement activation in vitro compared with PSU. Instantaneous clearance (69 +/- 8 vs. 58 +/- 3 ml/min; P < 0.001) and reduction rate (72.3 +/- 1 5% vs 66.2 +/- 6.1%; P < 0.001) of b2m were significantly higher with PES as compared with PSU. With higher molecular weight of proteins, differences in the solute removal between PES and PSU further increased, whereas albumin loss remained low (PES, 0.53 +/- 0.17 vs PSU, <0.22 g/dialysis). MPO, ELT and TAT did not differ between the two membranes. In contrast, leucopenia was less pronounced and C5a generation was significantly lower during dialysis with PES. CONCLUSIONS: Polyelectrolyte modification of PES results in a higher LMW protein removal and in optimized biocompatibility. Whether these findings translate into better outcome of patients receiving haemodialysis requires further studies.

Animals↗
PubMed2006

The effect of fluvastatin on cardiac outcomes in patients with moderate to severe renal insufficiency: a pooled analysis of double-blind, randomized trials.

BACKGROUND: Individuals with chronic kidney disease are at high risk for cardiovascular disease and have a high prevalence of hyperlipidemia. Lipid-lowering therapy may help patients with renal disease reduce their risk for cardiovascular events. METHODS: A pooled analysis of 30 completed clinical trials compared the efficacy and safety profiles of fluvastatin in subgroups of patients with moderate to severe renal insufficiency (creatinine clearance < 50 ml/min) and patients with normal renal function or mild renal insufficiency (creatinine clearance > or = 50 ml/min). RESULTS: Changes in lipid parameters with fluvastatin treatment were similar for the compared patient subgroups. Fluvastatin treatment reduced combined cardiac death and myocardial infarction by 41% compared with placebo among patients with moderate to severe renal insufficiency (hazard ratio, 0.59; p=0.007) and by 30% among patients with normal renal function or mild renal insufficiency (hazard ratio, 0.70; p=0.009). The relative reduction in the risk of major adverse cardiac events, a composite endpoint comprising cardiac death, nonfatal myocardial infarction, and coronary intervention procedures, with fluvastatin treatment was not significant for patients with moderate to severe renal insufficiency (hazard ratio, 0.83; p=0.18); in this patient subgroup, the incidence of coronary intervention procedures was similar between treatment groups. The safety profiles were similar for fluvastatin- and placebo-treated patients. CONCLUSIONS: The results of this pooled analysis indicate that fluvastatin is safe and effective for reducing cardiac death and nonfatal myocardial infarction in patients with moderate to severe renal insufficiency. Fluvastatin did not reduce the rate of coronary intervention procedures.

Anticholesteremic Agents↗
PubMed2006

Cross-talk between the kidney and the cardiovascular system.

In recent years, increasing evidence has been provided that even minor renal dysfunction is a powerful cardiovascular risk factor that induces typical cardiovascular alterations and thus predisposes to coronary heart disease as well as to noncoronary cardiovascular problems. This first had been noted in patients with diabetes but now has been confirmed amply in patients without diabetes as well. Numerous heterogeneous abnormalities have been described in patients with early renal dysfunction (e.g., microalbuminuria, reduced estimated GFR). One final common pathway seems to be endothelial cell dysfunction. The link between albuminuria and generalized endothelial cell dysfunction (as indicated by diminished flow-mediated vasodilation, markers of endothelial cell dysfunction, sloughed off endothelial cells, and high transcapillary albumin escape rate) is unclear. In patients with early renal dysfunction, a long list of classical and nonclassical cardiovascular risk factors have been identified: Elevated asymmetric dimethyl-l-arginine concentrations, markers of microinflammation, oxidative stress, features of metabolic syndrome, abnormal adipokine concentrations, dyslipidemia, inappropriate activation of the renin-angiotensin system, and sympathetic overactivity. The mechanisms that link dysfunction of the kidney and the cardiovascular system are being sought. The most interesting unifying concept, however, is deranged fetal programming linking nephron underdosing to the increased cardiovascular risk.

Cardiovascular System↗
PubMed2006

Impact of enzyme replacement therapy on cardiac morphology and function and late enhancement in Fabry's cardiomyopathy.

The present study evaluated the evolution of cardiac morphology, function, and late enhancement as a noninvasive marker of myocardial fibrosis, and their inter-relation during enzyme replacement therapy in patients with Fabry's disease using magnetic resonance imaging and color Doppler myocardial imaging. Late enhancement, which was present in up to 50% of patients, was associated with increased left ventricular mass, the failure of a significant regression of hypertrophy during enzyme replacement therapy, and worse segmental myocardial function. Late enhancement may predict the effect of enzyme replacement therapy on left ventricular mass and cardiac function.

Adult↗
PubMed2006

Lessons learnt from the 4D trial.

Renal dysfunction alters the pathogenesis of cardiovascular disease (CVD) profoundly conferring a very high-risk to the patients. Currently strategies are developed to combat CVD and clinical studies test a number of hypothesis. In this setting the results of the 4D study, comparing atorvastatin with placebo on cardiovascular outcomes in 1255 type 2 diabetic patients on maintenance hemodialysis, came as a great and unsuspected surprise. After a median follow-up of 4 years atorvastatin (20 mg/d) decreased the relative risk by 8% (95% confidence interval, 0.77-1.10; P=0.37) despite a high number of cardiovascular events and an overall 24% cardiovascular mortality. This indicates, that the risk in type 2 diabetic patients on hemodialysis origins from factors other than an atherogenic lipoprotein phenotype alone. Due to non-significant effects of atorvastatin on the primary endpoint and the different quality of such endpoints in dialysis patients as well as an unexplained higher rate of fatal strokes in atorvastatin treated patients we do not recommend to initiate statin treatment in patients with type 2 diabetes mellitus undergoing hemodialysis therapy at the present time. Statin therapy should be implemented earlier during the course of progressive vascular damage.

Atorvastatin↗
PubMed2006

An assessment of statin safety by nephrologists.

Recently, concerns regarding potential adverse effects of the statins on the kidney have been raised. The Kidney Expert Panel of the National Lipid Association's (NLA) Safety Task Force, made up of 3 nephrologists, was convened to review all of the currently available evidence pertinent to determining whether statins cause kidney injury, independent of the known, rare mechanisms of rhabdomyolysis and allergic, drug-induced, interstitial nephritis. The Panel reviewed published and unpublished evidence and found none that suggested that statins, when used in doses currently approved by the US Food and Drug Administration (FDA), cause kidney injury.

Dose-Response Relationship, Drug↗
PubMed2006

Hidden population substructures in an apparently homogeneous population bias association studies.

Linkage- and association-based approaches have been applied to attempt to unravel the genetic predisposition for complex diseases. However, studies often report contradictory results even when similar population backgrounds are investigated. Unrecognized population substructures could possibly explain these inconsistencies. In an apparently homogeneous German sample of 612 patients with type 2 diabetic and end-stage diabetic nephropathy and 214 healthy controls, we tested for hidden population substructures and their possible effects on association. Using a genetic vector space analysis of genotypes of 20 microsatellite markers, we identified four distinct subsets of cases and controls. The significance of these substructures was demonstrated by subsequent association analyses, using three genetic markers (UCSNP-43,-19,-63; intron 3 of the calpain-10 gene). In the undivided sample, we found no association between individual SNPs or any haplogenotypes (ie the genotype combination of two multilocus haplotypes) and type 2 diabetes. In contrast, when analyzing the four groups separately, we found that there was evidence for association of the common C allele of UCSNP-63 with the trait in the largest group (n=547 cases/101 controls; P=0.002). In this subset haplotype 112 was more frequent in controls than in cases (P=0.006; haplogenotype 112/121: odds ratio (OR)=0.27, 95% confidence intervals (CI)=0.13-0.57), indicating a protective effect against the development of type 2 diabetes. Our study demonstrates that unconsidered population substructures (ethnicity-dependent factors) can severely bias association studies.

Bias↗
PubMed2006

C-reactive protein: a family of proteins to regulate cardiovascular function.

Based on a multitude of clinical studies, C-reactive protein (CRP) has emerged as a risk marker for the development of cardiovascular disease, leading to recently published recommendations for screening the general population for plasma CRP level as a predictor for future cardiovascular events. However, uncertainties exist in how to apply these recommendations to populations with very high serum CRP levels and a high prevalence of cardiovascular disease, such as patients with end-stage renal disease. Furthermore, in vitro results are conflicting concerning the role of CRP in the vessel wall. Although many data are in favor of a proinflammatory effect of CRP, evidence is accumulating that CRP also exerts anti-inflammatory actions, mainly in neutrophils and platelets. Many of the apparently contradictory actions of CRP may be attributed to method issues, but, of interest, also may be explained by the existence of 2 distinct conformations of CRP, the native pentamer (nCRP) and modified CRP (mCRP) forms. nCRP is the classical acute-phase reactant detected in serum, whereas mCRP represents a predominantly tissue-bound form. It is detected immunohistochemically, mainly in and around endothelial and vascular smooth muscle cells. Although mCRP activates endothelial cells and neutrophils, induces neutrophil adhesion to the endothelium, and delays apoptosis of neutrophils in vitro, these effects were absent using nCRP. Clearly defined CRP conformers thus may provide a tool for how to reconcile the reported proinflammatory and anti-inflammatory properties of CRP. There is good evidence to believe that CRP is more than just a "bad guy," and further experiments are needed to determine how these 2 configurations contribute to atherogenesis, development of cardiovascular disease, and acute coronary events.

Animals↗
PubMed2006

The renal safety profile of fluvastatin: results of a pooled analysis.

A pooled analysis was designed to evaluate the effects of fluvastatin on the kidney, in terms of renal adverse events, laboratory abnormalities, and renal function over time. An analysis of adverse events was performed on data from 30 completed clinical trials of fluvastatin in 11,815 patients. An analysis of renal function was also performed on data from patients who participated in long-term studies >6 months in treatment duration. Creatinine clearance was calculated using the Cockcroft-Gault formula. Mean creatinine clearance values were in the normal to near-normal range at baseline. Changes in creatinine clearance and serum creatinine from baseline were similar in fluvastatin-treated patients and placebo-treated patients. In the all-fluvastatin group, mean creatinine clearance (+/-standard deviation) increased from 87.8 (+/-42.8) mL/min at baseline to 89.4 (+/-41.2) mL/min at endpoint. In the placebo group, mean creatinine clearance (+/- standard deviation) increased from 87.7 (+/- 43.9) mL/min at baseline to 88.7 (+/-41.4) mL/min at endpoint. In the all-fluvastatin group, mean serum creatinine (+/- standard deviation) decreased from 1.14 (+/-0.20) mg/dL at baseline to 1.11 (+/-0.20) mg/dL at endpoint. In the placebo group, mean serum creatinine (+/-standard deviation) decreased from 1.15 (+/-0.22) mg/dL at baseline to 1.12 (+/-0.22) mg/dL at endpoint. The incidence of renal adverse events was low and comparable between the fluvastatin and placebo treatment groups. This pooled analysis demonstrates that fluvastatin treatment across the approved daily dose range of 20 mg to 80 mg does not adversely affect creatinine or creatinine clearance over time in dyslipidemic patients.

Anticholesteremic Agents↗
PubMed2006

Fabry disease: guidelines for the evaluation and management of multi-organ system involvement.

Fabry disease is an X-linked metabolic storage disorder due to the deficiency of lysosomal alpha-galactosidase A, and the subsequent accumulation of glycosphingolipids, primarily globotriaosylceramide, throughout the body. Males with classical Fabry disease develop early symptoms including pain and hypohidrosis by the second decade of life reflecting disease progression in the peripheral and autonomic nervous systems. An insidious cascade of disease processes ultimately results in severe renal, cardiac, and central nervous system complications in adulthood. The late complications are the main cause of late morbidity, as well as premature mortality. Disease presentation in female heterozygotes may be as severe as in males although women may also remain asymptomatic. The recent introduction of enzyme replacement therapy to address the underlying pathophysiology of Fabry disease has focused attention on the need for comprehensive, multidisciplinary evaluation and management of the multi-organ system involvement. In anticipation of evidence-based recommendations, an international panel of physicians with expertise in Fabry disease has proposed guidelines for the recognition, evaluation, and surveillance of disease-associated morbidities, as well as therapeutic strategies, including enzyme replacement and other adjunctive therapies, to optimize patient outcomes.

Adult↗
PubMed2006

Dyslipidemia, inflammation and dialysis outcomes: what we know now.

PURPOSE OF REVIEW: The limited prognosis of patients with chronic kidney disease starts when renal function begins to decline. RECENT FINDINGS: Available interventions did not prove their efficacy. Treatment of dyslipidemia and inflammation by statins was shown to be effective in post-hoc subgroup analyses of large-scale randomized controlled trials in patients with chronic kidney disease stages 2 and 3. So far, randomized controlled trials in dialysis patients (HEMO, ADEMEX, 4D study) and after kidney transplantation (ALERT study) have produced so-called 'negative results'. It is most likely that these trials had limited power to prove the primary hypothesis. It is also probable that cardiac disease in renal patients changes its character from a vascular atherosclerotic to a more complex structural heart disease in combination with stiff arteries (arteriosclerosis). Clinically, this leads to a high proportion of sudden cardiac deaths: of 270 cardiac deaths in the 4D trial, 160 were of sudden cardiac origin. A complex pathogenetic process and a number of new emerging cardiovascular disease risk factors in the setting of high-grade inflammation/infection are proposed as being responsible. SUMMARY: This review focuses on outcome variables in diabetic hemodialysis patients with special focus on risk factors such as inflammation and dyslipidemia.

C-Reactive Protein↗
PubMed2006

Lipid changes and statins in chronic renal insufficiency.

It has been known for a long time that chronic kidney disease (CKD) is associated with dyslipidemia, but the full extent of abnormalities has been appreciated only recently, because routine laboratory tests fail to disclose the entire spectrum of lipid abnormalities. Lipids, particularly HDL cholesterol, are predictive of cardiovascular events, but a paradoxic inverse relation between cholesterol concentration and cardiovascular death has been noted in uremic patients. This currently is thought to be explained by the confounding effect of microinflammation and possibly calcification, but this is not definitely proved. Several retrospective analyses that included patients with mild or moderate CKD documented benefit from lowering of cholesterol by statins. In contrast, the Die Deutsche Diabetes Dialyse (4D) study and a small Scandinavian study failed to show a benefit from lowering of cholesterol by statins in ESRD. Pathomechanistically, it is possible that nonclassical pathomechanisms override statin-sensitive mechanisms as also suggested by the observation that statins fail to reduce carotid intima-media thickening. Although, experimentally, exposure to lipids (particularly oxidized lipids) aggravates progression, data on the effect of statins on progression in patients with CKD are not definite. The most likely explanation is that the impact of numerous confounders obscures their effect on progression. The increase in urinary protein excretion of patients who are treated with statins had been a cause of concern, but the underlying mechanism (i.e. interference with proximal tubular reabsorption of protein) meanwhile has been well documented.

Atherosclerosis↗
PubMed2005

Impact of oxidized low density lipoprotein on vascular cells.

Oxidized LDL (OxLDL) is a proatherogenic lipoprotein, accumulating in the vascular wall and contributing to the pathogenesis of vascular dysfunction early in the development of atherosclerosis. Enhanced serum levels of OxLDL, as well as antibodies against its epitopes, are predictive for endothelial dysfunction and coronary heart disease. While enhanced oxidative stress is one factor triggering formation of OxLDL, OxLDL itself has been identified as a potent stimulus for vascular oxygen radical formation, causing a vicious circle. OxLDL-induced O(2)(-) formation, largely through activation of NADPH oxidase, but also through uncoupling of endothelial NO-synthase and through direct O(2)(-) release, leads to endothelial dysfunction. Furthermore, OxLDL-induced O(2)(-) formation has a strong impact on tissue remodeling, resulting in either cell growth - proliferation or hyperplasia - or apoptotic cell death. The effect of OxLDL on cell cycle regulation is mediated by activation of the small GTPase RhoA and consequent regulation of p27(KIP1), a key enzyme of the cell cycle. In addition, OxLDL-induced activation of RhoA sensitizes the contractile apparatus of the vessel wall, enhancing the contractile tonus and favoring vasospasm. Thus, through a variety of mechanisms, OxLDL importantly contributes to vascular dysfunction and remodeling.

Animals↗