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Biomedical subjects

B Fellström

Publications and source records attributed to B Fellström.

At least 19 recordsLinked to original sources

Renal dysfunction is a strong and independent risk factor for mortality and cardiovascular complications in renal transplantation.

Renal transplant recipients (RTR) have shortened life expectancy, primarily due to premature cardiovascular disease (CVD). Traditional CVD risk factors are highly prevalent. In addition, several non-traditional risk factors may contribute to the high risk. The aim of the study was to evaluate the effects of renal dysfunction on mortality and cardiovascular complications in 1052 placebo-treated patients of the Assessment of LEscol in Renal Transplantation (ALERT) trial. Follow-up was 5-6 years and endpoints included cardiac death, non-cardiovascular death, all-cause mortality, major adverse cardiac event (MACE), non-fatal myocardial infarction (MI) and stroke. The effects of serum creatinine at baseline on these endpoints were evaluated. Elevated serum creatinine in RTR was a strong and independent risk factor for MACE, cardiac, non-cardiovascular, and all-cause mortality, but not for stroke or non-fatal MI alone. Serum creatinine was associated with increased mortality and MACE, independent of established CVD risk factors. Graft loss resulted in increased incidences of non-cardiovascular death, all-cause mortality, MACE and non-fatal MI. In conclusion, elevated serum creatinine is a strong risk factor for all-cause, non-cardiovascular and cardiac mortality, and MACE, independent of traditional risk factors, but not for stroke or non-fatal MI alone.

Cardiovascular Diseases↗

Long-term cardiac outcomes in renal transplant recipients receiving fluvastatin: the ALERT extension study.

Renal transplant recipients (RTR) have an increased risk of premature cardiovascular disease. The ALERT study is the first trial to evaluate the effect of statin therapy on cardiac outcomes following renal transplantation. Patients initially randomized to fluvastatin or placebo in the 5-6 year ALERT study were offered open-label fluvastatin XL 80 mg/day in a 2-year extension to the original study. The primary endpoint was time to first major adverse cardiac event (MACE). Of 1787 patients who completed ALERT, 1652 (92%) were followed in the extension. Mean total follow-up was 6.7 years. Mean LDL-cholesterol was 98 mg/dL (2.5 mmol/L) at last follow-up compared to a pre-study level of 159 mg/dL (4.1 mmol/L). Patients randomized to fluvastatin had a reduced risk of MACE (hazards ratio [HR] 0.79, 95% CI 0.63-0.99, p = 0.036), and a 29% reduction in cardiac death or definite non-fatal MI (HR 0.71, 95% CI 0.55-0.93, p = 0.014). Total mortality and graft loss did not differ significantly between groups. Fluvastatin produces a safe and effective reduction in LDL-cholesterol associated with reduced risk of MACE in RTR. The lipid-lowering and cardiovascular benefits of fluvastatin are comparable to those of statins in other patient groups, and support use of fluvastatin in RTR.

Adult↗

Cyclosporine nephrotoxicity.

The introduction of cyclosporine (CSA) into organ transplantation was a landmark achievement leading to a substantial improvement of the early transplant results. It was particularly the reduction in early severe acute rejections that accounted for this improvement. However, on a long-term basis development of chronic transplant nephropathy did not seem to become counteracted by CSA. Conversely, CSA may cause both acute and chronic nephrotoxicity, with reduced renal transplant function along with arteriolopathy and interstitial fibrosis. This is the shortcoming of CSA as well as other calcineurin inhibitors (CNIs) such as tacrolimus (TAC). Other immunosuppressive agents were developed subsequently, including Target of Rapamycin (ToR) blockers and mycophenolate mofetil (MMF), which were not nephrotoxic. Current strategies to overcome CNI toxicity include reduction or even stopping administration of CSA or TAC along with switching to a sirolimus, everolimus or MMF based regimen. This strategy has been documented (and there are currently additional ongoing studies) to cause an improvement in renal transplant function or to reduce the deterioration rate. These measures to deal with CSA toxicity need further documentation, since a preserved good renal function seems to not only have an important impact on graft survival but also on patient survival.

Acute Disease↗

Candesartan cilexetil reduces graft arteriosclerosis in aortic transplantation model in rat.

To date established treatment of transplant arteriosclerosis is basically missing and there is a need for new therapeutic approaches. Angiotensin II (Ang II) and Ang II receptor type 1 (AT) are present in the vascular wall. Blocking of the AT1 receptor by pharmacological agents may inhibit damaging effects of Ang II on endothelial and smooth muscle cells. The purpose of the study was to evaluate the effect of the AT1 receptor blocker Candesartan cilexetil on the development of graft arteriosclerosis in a rat aortic transplant model. Two strain combinations were used for aortic transplantation: DA to PVG; and PVG to PVG. The animals received Candesartan cilexetil treatment (9.5 + 1.4 mg/kg/day) for 8 weeks. Candesartan cilexetil treatment reduced neointimal formation both in allografts (Qint 30.2 +/- 8.8% vs. 22.1 +/- 8.7%, P < 0.05) and in isografts (Qint 15.5 +/- 4.4% vs. 6.7 +/- 3.3%, P = 0.0001). Blocking of the AT1 receptor signalling by Candesartan cilexetil was also associated with a reduced expression of TGF-beta1. Macrophage infiltration was not affected by the treatment. Candesartan cilexetil treatment leads to reduced neointimal formation in aortic transplant. The positive effect of the drug might be partly explained by a reduction of TGF-beta1 expression in the grafts. Candesartan treatment may provide another possibility for prevention of transplant arteriosclerosis and chronic rejection.

Animals↗

Impaired endothelium-dependent vasodilatation in renal failure in humans.

BACKGROUND: The main causes of death in patients with chronic renal failure (CRF) are cardiovascular complications. The aim of the present study was to compare endothelium-dependent vasodilatation (EDV) in patients with chronic renal failure with a control population controlling for hypertension, diabetes mellitus and hypercholesterolaemia. METHODS: Fifty-six patients with moderate CRF (mean creatinine clearance 29.4 ml/min/1.73 m(2)) underwent evaluation of EDV and endothelium-independent vasodilatation (EIDV) by means of forearm blood flow (FBF) measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (Mch, 2 and 4 microg/min evaluating EDV) and sodium nitroprusside (SNP, 5 and 10 microg/min evaluating EIDV). Fifty-six control subjects without renal impairment underwent the same investigation. RESULTS: Infusion of Mch increased FBF significantly less in patients with renal failure than in controls (198 vs 374%, P<0.001), whereas no significant difference was seen regarding the vasodilatation induced by SNP (278 vs 269%). The differences in EDV between the groups were still significant after controlling for hypertension, blood glucose, and serum cholesterol in multiple regression analysis (P<0.001). EDV was related to serum creatinine (r=-0.37, P<0.01), creatinine clearance (r=0.45, P<0.005) and to serum triglyceride levels (r=-0.29, P<0.005) in the CRF group. CONCLUSIONS: Patients with moderate CRF have an impaired EDV even after correction for traditional cardiovascular risk factors and this impairment is related to the degree of renal failure.

Aged↗

Effects of fluvastatin on cardiac events in renal transplant patients: ALERT (Assessment of Lescol in Renal Transplantation) study design and baseline data.

BACKGROUND: Recent clinical trials of primary and secondary prevention of cardiovascular disease have demonstrated that lowering plasma cholesterol with 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors ('statins') reduces morbidity and mortality from coronary heart disease in diverse patient populations. STUDY AIMS: The aim of the present ALERT (Assessment of Lescol in Renal Transplantation) study is to determine whether renal transplant recipients would also benefit from statin therapy. ALERT is a multicentre, randomized, double-blind, placebo-controlled trial to assess the effect of fluvastatin in renal transplant recipients with mild-to-moderate hypercholesterolaemia. The primary objective is to investigate the effects of fluvastatin on major adverse cardiac events (MACE). In addition, the effects on cardiovascular and all-cause mortality, as well as renal function, will be addressed. STUDY POPULATION: The study population contains patients with functioning renal allografts of more than 6 months' duration, recruited from 75 centres in Northern Europe and Canada. Patients of both sexes, aged 30-75 years, with a total cholesterol level of 4.0-9.0 mmol/l (155-348 mg/dl) were included, except for those with a history of myocardial infarction, where the upper limit for inclusion was 7.0 mmol/l (270 mg/dl). STUDY DESIGN: A total of 2100 patients were recruited by the end of October 1997 and will be followed for up to 6 years. This report presents the design features of the study (recruitment, follow-up, sample size, data analysis and study organization), along with baseline results. ALERT is the first large-scale prospective, randomized, double-blind study to address the prevention of cardiovascular mortality in renal transplant patients receiving an HMGCoA reductase inhibitor.

Adult↗

Risk factors for and management of post-transplantation cardiovascular disease.

The mortality rates due to cardiovascular disease (CVD) in transplant recipients are greater than in the general population. CVD is a major cause of both graft loss and patient death in renal transplant recipients, and improving cardiovascular health in transplant recipients will presumably help to extend both patient and graft survival. Further studies are needed to better evaluate the effectiveness of risk modification on subsequent CVD morbidity and mortality. There is no reason to consider risk factors for CVD such as hyperlipidaemia, hypertension and diabetes mellitus in transplant recipients differently from in the general population. In addition, there are specific transplantation risk factors such as acute rejection episodes and the use of immunosuppressive drugs. It is obvious that several of the immunosuppressive agents used today have disadvantageous influences on risk factors for CVD such as hyperlipidaemia, hypertension and post-transplantation diabetes mellitus (PTDM), but the relative importance of immunosuppressant-induced increases in these risk factors is basically unknown. This may be a strong argument for the selective use and individual tailoring of immunosuppressive agents based upon the risk factor profile of the patient, without jeopardising the function of the graft. Hyperlipidaemia is common after transplantation, and immunosuppression with corticosteroids, cyclosporin, or sirolimus (rapamycin) causes different types of post-transplantation hyperlipidaemia. However, to date, no studies have demonstrated that lipid lowering strategies significantly reduce CVD morbidity or mortality and improve allograft survival in transplant recipients. Several studies using preventive or interventional approaches are ongoing and will be reported in the near future. Post-transplantation hypertension appears to be a major risk factor determining graft and patient survival, and immunosuppressive agents have different effects on hypertension. Controlled studies support the opinion that post-transplantation hypertension must be treated as strictly as in a population with essential hypertension, diabetes mellitus, or chronic renal failure. As increasing numbers of immunosuppressive agents become available for use, we may be in a better position to tailor immunosuppressive therapy to the individual patient, avoiding the use of diabetogenic drugs, drug combinations, or inappropriate doses in patients susceptible to PTDM. Multiple acute rejection episodes have also been demonstrated to be a risk factor for CVD - a strong argument for the use of immunosuppressive drugs to reduce acute rejection. Until we have a better understanding from ongoing landmark studies on the management of CVD, presently available therapy to reduce risk factors needs to be used together with individual tailoring of immunosuppressive therapy with the aim of reducing CVD in these patients.

Antihypertensive Agents↗

Oxidative stress markers in pre-uremic patients.

AIM: The present study was designed to investigate a complex of oxidative stress (OS) markers in patients with chronic renal failure (CRF) and to study the relationship between different OS markers and degree of renal failure. The following indices of OS were measured in plasma: oxidized glutathione (GSSG), reduced glutathione (GSH), total glutathione (TGSH), glutathione redox ratio (GSSG/GSH) and resistance of lipoprotein fraction to oxidation (lag phase of LPF). Baseline diene conjugation level of lipoprotein fraction (BDC-LPF), total antioxidative activity (TAA), diene conjugates (DC), lipid hydroperoxides (LOOH) and thiobarbituric acid-reactive substances (TBARS) were measured in serum. All markers in plasma and serum were measured both in patients with CRF and in healthy controls. SUBJECTS AND METHODS: Blood samples were obtained from 38 patients with CRF and from 61 healthy controls. Routine biochemical analyses were performed by using commercially available kits. RESULTS: Levels of DC, BDC-LPF, LOOH, GSSG and GSSG/GSH ratio were significantly increased and lag phase of LPF was significantly shortened in patients with CRF compared with healthy controls. Serum creatinine and urea levels correlated significantly with GSSG level and GSSG/GSH in patients with CRF. A significant inverse correlation was found between glutathione redox ratio and lag phase of LPF and between GSSG level and BDC-LPF. CONCLUSIONS: The findings suggest that renal patients are in a state of oxidative stress compared with healthy controls. The most informative indices to evaluate the degree of OS in CRF were: GSSG level, GSSG/GSH status, lag phase of LPF and BDC-LPF.

Aged↗

Impact and management of hyperlipidemia posttransplantation.

CVD morbidity and mortality is a major cause of premature death and allograft loss in recipients of renal and cardiac transplants, and hyperlipidemia--a major risk factor for CVD in the general population--may be a significant risk factor for CVD in transplant recipients. Hyperlipidemia is common after transplantation, and immunosuppression with corticosteroids, cyclosporine, or sirolimus causes posttransplantation hyperlipidemia. Posttransplantation hyperlipidemia can be treated in various ways, but statin therapy has thus far proved to be the most effective in lowering lipid levels in the transplant population. However, to date, no large solid end-point studies have demonstrated that lipid-lowering therapy with statins (or any other class of agents) significantly reduces CVD morbidity or mortality and improves allograft survival in transplant recipients, although some smaller studies point in that direction. The ongoing ALERT trial is currently studying whether early and later intervention with a statin (fluvastatin) can reduce chronic allograft dysfunction, decrease CVD, and improve patient survival in transplant recipients.

Heart Transplantation↗

Evaluation of endothelium-dependent vasodilation in the human peripheral circulation.

Flow-mediated vasodilation (FMD) in the brachial artery measured by ultrasound, and the increase in forearm blood flow (FBF) induced by local infusion of a muscarinic-receptor agonist have both frequently been used to evaluate endothelium-dependent vasodilation (EDV) in the human forearm. The present study intended to evaluate the relationship between these techniques and to investigate if vasodilation induced by the muscarinic receptor-agonist methacholine (MCh) was owing to production of nitric oxide (NO). FMD during hyperaemia was assessed by ultrasound and FBF was measured by venous occlusion plethysmography during local infusion of MCh or L-arginine in the human forearm. Both these methods were applied in 26 individuals. In another 12 individuals forearm arterial and venous plasma concentrations of nitrate/nitrite (NOx) were measured together with FBF before and during local MCh infusion. While the change in brachial artery diameter induced by sublingually given nitroglycerine and the vasodilatory response to sodium nitroprusside (SNP) given locally in the forearm were significantly correlated (r = 0.70, P < 0.01), FMD showed no relationship with the vasodilation evoked by MCh (r = -0.03) or L-arginine (r = 0.04). The five-fold increase in FBF during MCh infusion was associated with a significant increase in venous plasma NOx concentrations (P < 0.05) and a more than 11-fold increase in forearm NOx-release (P < 0.01). Thus, a significant relationship between the two methods regarding the evaluation of endothelium-independent vasodilation evoked by NO-donors was found, but no relationship was found between the two methods regarding the evaluation of endothelium-dependent vasodilation. Furthermore, vasodilation induced by MCh in the forearm seems to be induced by NO-release.

Adult↗

Increased fracture rate in diabetes mellitus and females after renal transplantation.

BACKGROUND: Bone disease and fractures after organ transplantation pose severe clinical problems. About 20% of renal transplant patients have type 1 diabetes (IDDM). However, data are scarce in the literature about the occurrence of spontaneous fractures in IDDM patients posttransplantation. METHODS: In this cross-sectional study using a questionnaire and hospital records the prevalence of symptomatic bone disease was investigated in 193 renal transplanted patients with functioning renal grafts 6 months to 23 years after the transplantation. RESULTS: The frequency of IDDM was 18%. In the total group the rate of osteoporotic fractures posttransplantation was 17%, and the majority of fractures occurred within the first 3 years after the transplantation. A high rate of fractures, 40%, was noted in the diabetes group (P<0.001), compared with 11% in the nondiabetes group. Fractures seen in IDDM were often multiple and located mostly in the appendicular skeleton, i.e., in ankles and feet. Female gender was also associated with an elevated fracture rate, 23% (P<0.05). CONCLUSION: An increased incidence of osteoporotic fractures after renal transplantation was found in diabetic and female patients. The mechanism behind bone fragility in IDDM is multifactorial and despite a restored renal function bone disease may progress, and is probably enhanced by the immunosuppressive treatment.

Cross-Sectional Studies↗

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.

Adult↗

Altered flow properties of blood and increased plasma fibrinogen in cyclosporin-treated renal allograft recipients.

BACKGROUND: Abnormalities in blood rheology may be factors contributing to cardiovascular complications and the progression of renal failure in kidney allograft recipients. The haemorheological variables haematocrit, fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency and fluidity were measured in 27 cyclosporin A (CyA)-treated patients who had received a renal graft at least 6 months previously. Their creatinine clearance was in the range of 12-92 ml/min/1.73 m2 (mean 55+/-19). The values were compared with those obtained from a control group comprising 20 healthy subjects matched according to age, sex and smoking habits. RESULTS: The haematocrit, plasma fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency, body mass index (BMI), mean arterial pressure (MAP) and serum triglycerides were increased in the transplanted patients, and the serum high density lipoprotein (HDL)-cholesterol and erythrocyte fluidity decreased. The haemorheological variables were used as dependent variables in a stepwise regression analysis with age, MAP, BMI, urinary albumin excretion rate, blood CyA concentration, creatinine clearance, and serum triglycerides, cholesterol and HDL-cholesterol as independent variables. Plasma fibrinogen was positively correlated with BMI and blood CyA. The whole blood viscosity was positively correlated with blood CyA and negatively with serum HDL-cholesterol. Only serum triglycerides remained correlated with erythrocyte aggregation tendency. CONCLUSIONS: All variables with a known impact on blood viscosity were altered in the present group of renal transplant recipients. Inappropriate regulation of erythrocyte formation, overweight, the use of CyA, high triglycerides and low HDL-cholesterol levels may be factors contributing to this. The importance of impaired flow properties of blood for the development of cardiovascular diseases and transplant glomerulosclerosis needs to be examined.

Adult↗