| 1. |
- Annuk, Margus, et al.
(author)
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Cyclooxygenase inhibition improves endothelium-dependent vasodilatation in patients with chronic renal failure
- 2002
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In: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 17:12, s. 2159-2163
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Journal article (peer-reviewed)abstract
- BACKGROUND: Some studies have demonstrated beneficial effects of L-arginine as a substrate for nitric oxide synthesis, and diclofenac as an inhibitor of cyclooxygenase (COX)-derived vasoconstrictive agents on vascular responses in humans during several pathological conditions. The aim of the present study was to investigate the acute effects of L-arginine and diclofenac on endothelium-dependent vasodilatation (EDV) and endothelium-independent vasodilatation (EIDV) in patients with chronic renal failure (CRF). METHODS: Effects of L-arginine and diclofenac on EDV and EIDV were measured in 15 patients with CRF and in 15 healthy controls by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (2 and 4 micro g/min evaluating EDV) and sodium nitroprusside (5 and 10 micro g/min evaluating EIDV). RESULTS: L-Arginine infusion increased methacholine-induced vasodilatation both in patients with CRF and healthy controls. Diclofenac infusion increased methacholine-induced vasodilatation only in patients with CRF. There was no significant change in nitroprusside-induced vasodilatation after L-arginine and diclofenac infusions both in patients with CRF and healthy controls. CONCLUSIONS: These results suggest that COX inhibition reduces the levels of a prostanoid-derived vasoconstrictive agent contributing to the impaired EDV in patients with CRF, while in this age group L-arginine improves EDV regardless of renal function.
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| 2. |
- Annuk, Margus, et al.
(author)
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Endothelium-dependent vasodilation and oxidative stress in chronic renal failure : impact on cardiovascular disease
- 2003
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In: Kidney International, Supplement. - 0098-6577. ; :84, s. S50-S53
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Journal article (other academic/artistic)abstract
- Despite significant progress in renal replacement therapy, the mortality from cardiovascular disease (CVD) in patients with chronic renal failure (CRF) is many times higher than in the general population. The traditional risk factors are frequently present in CRF patients. However, based upon conventional risk factor analysis, these factors do not fully explain the extraordinary increase in morbidity and mortality in CVD among patients with CRF. Accumulating evidence suggests that CRF is associated with impaired endothelial cell function. In recent years, the role of endothelial dysfunction (ED) and excessive oxidative stress (OS) in the development of CVD has been highlighted. ED is an early feature of vascular disease in different diseases such diabetes, hypertension, hypercholesterolemia, and coronary heart disease. The precise mechanism which induces ED is not clear. Several factors however, including OS-related accumulation of uremic toxins, hypertension and shear stress, dyslipidemia with cytotoxic lipoprotein species such as small, dense low-density lipoprotein (LDL) particles, competitive inhibition of endothelial nitric oxide (NO) by increased production by asymmetrical dimethylarginine (ADMA) are pathogenic. In addition, it is known that excessive OS causes ED. An overproduction of reactive oxygen species (ROS) may injure the endothelial cell membrane, inactivate NO, and cause oxidation of an essential cofactor of nitric oxide synthase (NOS). Recent studies have demonstrated that an impaired endothelium-dependent vasodilation and OS are closely related to each other in patients with CRF.
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| 3. |
- Annuk, Margus, et al.
(author)
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Impaired endothelium-dependent vasodilatation in renal failure in humans
- 2001
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In: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 16:2, s. 302-306
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Journal article (peer-reviewed)abstract
- 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.
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| 4. |
- Annuk, Margus, et al.
(author)
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Oxidative stress and endothelial function in chronic renal failure
- 2001
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In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 12:12, s. 2747-2752
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Journal article (other academic/artistic)abstract
- This study aimed to investigate the relationship between oxidative stress and endothelium-dependent vasodilation in patients with chronic renal failure (CRF). Thirty-seven patients with CRF underwent evaluation of endothelium-dependent vasodilation and endothelium-independent vasodilation by means of forearm blood flow measurements with venous occlusion plethysmography during local intra-arterial infusions of methacholine (evaluating endothelium-dependent vasodilation) and sodium nitroprusside (evaluating endothelium-independent vasodilation). Lag phase of lipoprotein fraction to oxidation, total antioxidative activity, diene conjugates, thiobarbituric acid reactive substances, lipid hydroperoxide, reduced glutathione (GSH), oxidized GSH (GSSG), and the GSH redox ratio (GSSG/GSH) were all measured as markers of oxidative stress. Two groups of healthy subjects (61 and 37 subjects, respectively) were used as controls. In one group, oxidative stress markers were measured, whereas endothelium-dependent vasodilation and endothelium-independent vasodilation were assessed in the other group. Compared with controls, the patients with renal insufficiency had an impaired endothelium-dependent vasodilation, a shorter lag phase of lipoprotein fraction, and higher levels of diene conjugates, lipid hydroperoxide, and GSSG levels. The GSSG/GSH ratio was lower in patients with CRF. Endothelium-dependent vasodilation was positively correlated with total antioxidative activity (r = 0.41, P = 0.016), GSH (r = 0.44, P < 0.0098), and lag phase of LDL (r = 0.35, P = 0.036) and negatively correlated with GSSG (r = -0.40, P < 0.018), GSSG/GSH (r = -0.47, P = 0.0057), and diene conjugates (r = -0.53 P < 0.0015) in patients with CRF. These results show that an impaired endothelium vasodilation function and oxidative stress are related to each other in patients with CRF.
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| 5. |
- Annuk, Margus, et al.
(author)
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Oxidative stress markers in pre-uremic patients
- 2001
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In: Clinical Nephrology. - 0301-0430. ; 56:4, s. 308-314
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Journal article (pop. science, debate, etc.)abstract
- 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.
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| 6. |
- Fellström, Bengt, et al.
(author)
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Effect of fluvastatin on renal end points in the Assessment of Lescol in Renal Transplant (ALERT) trial
- 2004
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In: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 66:4, s. 1549-1555
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Journal article (peer-reviewed)abstract
- BACKGROUND: Hyperlipidemia is a risk factor for long-term renal transplant dysfunction, but no prospective clinical trials have investigated the effects of statin treatment on graft function in renal transplant recipients. The aim of the present study was to evaluate the effect of fluvastatin on long-term renal transplant function and development of chronic allograft nephropathy in the ALERT (Assessment of Lescol in Renal Transplantation) study. METHODS: ALERT was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin, 40 mg and 80 mg daily, in renal transplant recipients. Patients were randomized to receive either fluvastatin (N= 1050) or placebo (N= 1052) and followed for five to six years. Renal end points included graft loss or doubling of serum creatinine or death; glomerular filtration rate (GFR) was also measured during follow-up in a subset of patients (N= 439). RESULTS: There were 283 patients (13.5%) with graft loss, mainly due to chronic rejection (82%), yielding an annual rate of 2.4%. Fluvastatin treatment significantly lowered mean low-density lipoprotein (LDL)-cholesterol levels by 32% (95% CI -33 to -30) compared with placebo, but had no significant effect on the incidence of renal graft loss or doubling of serum creatinine, or decline in GFR throughout follow-up in the whole study population. Neither was any treatment effect by fluvastatin found in any of the subgroups analyzed. CONCLUSION: Fluvastatin treatment significantly improves lipid values in renal transplant recipients but has no effect on graft loss or doubling of serum creatinine.
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| 7. |
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| 8. |
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| 9. |
- Jardine, Alan G., et al.
(author)
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Fluvastatin prevents cardiac death and myocardial infarction in renal transplant recipients : post-hoc subgroup analyses of the ALERT Study
- 2004
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In: American Journal of Transplantation. - : Elsevier BV. - 1600-6135 .- 1600-6143. ; 4:6, s. 988-995
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Journal article (peer-reviewed)abstract
- Renal transplant recipients have a greatly increased risk of premature cardiovascular disease. The ALERT study was a multicenter, randomized, double-blind, placebo-controlled trial of fluvastatin (40-80 mg/day) in 2102 renal transplant recipients followed for 5-6 years. The main study used a composite cardiac end-point including myocardial infarction, cardiac death and cardiac interventions. Although reduced by fluvastatin, this primary end-point failed to achieve statistical significance thus precluding analysis of predefined subgroups. Therefore, in the present survival analysis, we used an alternative primary end-point of cardiac death or definite nonfatal myocardial infarction (as used in other cardiac outcome trials) which was significantly reduced by Fluvastatin therapy and permits subgroup analysis. Fluvastatin reduced LDL-cholesterol by 1 mmol/L compared with placebo, and the incidence of cardiac death or definite myocardial infarction was reduced from 104 to 70 events (RR 0.65; 95% CI 0.48, 0.88; p = 0.005). Fluvastatin use was associated with reduction in cardiac death or nonfatal myocardial infarction, which achieved statistical significance in many subgroups. The subgroups included patients at lower cardiovascular risk, who were younger, nondiabetic, nonsmokers and without pre-existing CVD. These data support the early introduction of statins following renal transplantation.
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| 10. |
- Lind, Lars, et al.
(author)
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Evaluation of endothelium-dependent vasodilation in the human peripheral circulation
- 2000
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In: Clinical Physiology. - : Wiley. - 0144-5979 .- 1365-2281. ; 20:6, s. 440-448
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Journal article (peer-reviewed)abstract
- 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.
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