Oxidative stress, endothelial function, carotid artery intimal thickness and their correlates among chronic peritoneal dialysis patients

Markers of Oxidative Stress, Inflammation, and Endothelial Dysfunction in Diabetic and Nondiabetic Patients with Chronic Kidney Disease on Peritoneal Dialysis

Chronic kidney disease (CKD) is a low-grade inflammatory state which is accom-panied by elevated markers of oxidative stress, inflammatory, and endothelial dysfunction in patients on peritoneal dialysis (PD). These represent a key triad for the development and progression of atherosclerosis. The present study assessed the markers of oxidative stress, inflammatory and endothelial dysfunction in diabetic and non-diabetic CKD patients on PD. A cross-sectional study was undertaken on 100 CKD patients on PD, of whom 52 patients were nondiabetic and 48 were diabetic patients. Blood samples were estimated for malondialdehyde (MDA) and ferric reducing ability of plasma (FRAP) as markers of oxidative stress; interleukin (IL)-6, high-sensitivity C-reactive protein (hs-CRP), and fibrinogen as inflammatory markers; and markers of endothelial dysfunction such as nitric oxide (NO), carotid wall intimal medial thickness (CIMT), and number of plaques, among others. The MDA levels increased and FRAP levels decreased in both diabetic and nondiabetic CKD patients on PD. The levels of IL-6, hs-CRP, fibrinogen, NO, CIMT, and the number of plaques were significantly higher in diabetic patients than in nondiabetic CKD patients on PD. The lipid profile was significantly atherogenic in diabetic patients compared with nondiabetics CKD patients. The results showed increased oxidative stress, inflammation, and endothelial dysfunction in diabetic patients compared with nondiabetics CKD patients on PD.

Cardiovascular Risk Factors and Markers of Atherosclerosis in Stable Kidney Transplant Recipients

BACKGROUND

There is limited evidence regarding the risk factors influencing vascular injury in kidney transplant recipients, except for accelerated vasculopathy and endothelial dysfunction in the pre-transplantation period of end-stage renal failure. Therefore, we performed a cross-sectional study to evaluate the role of traditional and novel or potential nontraditional risk factors in vascular and endothelial dysfunction in a cohort of stable kidney transplant recipients.

METHODS

One hundred forty-two kidney transplant recipients at 8.4 ± 1.8 years after transplantation were enrolled into the study. Different markers of vascular injury, such as carotid intima-media thickness (IMT), pulse wave velocity (PWV), and peripheral arterial tonometry (PAT), were assessed. Inflammatory markers, oxidative stress and endothelial function surrogate markers, adhesion molecules, and parathormone and osteoprotegerin levels were measured.

RESULTS

Among traditional risk factors, only age, pre-transplantation diabetes, left ventricular hypertrophy (LVH) and cardiovascular disease (CVD) were related to increased IMT and PWV, whereas PAT values were significantly decreased only in diabetics and patients with CVD and were similar in patients with and without LVH. In multivariate regression analysis, IMT was explained by age, previous CVD episodes, and higher high-sensitivity C-reactive protein levels, and PWV by age and pre-transplantation diabetes. The regression analysis failed to find any significant explanatory variables for PAT.

CONCLUSIONS

1. In stable kidney transplant recipients, age, pre-transplantation diabetes, previous cardiovascular episode, and systemic microinflammation were predictors of vascular injury. 2. PAT is poorly associated with traditional CV risk factors and does not correspond with levels of biochemical markers of endothelial dysfunction in those patients.

Effect of vitamin C on endothelial function of children with chronic renal failure: An experimental study

Background:

It is well established that improvement of endothelial dysfunction (ED) could prevent or delay the occurrence of cardiovascular disease (CVD) and its related morbidity and mortality in patients with chronic kidney disease (CKD). In this study we investigated whether administration of vitamin C could be effective by improving brachial artery flow-mediated dilation (FMD) and intima media thickness (IMT), two surrogate markers of ED, in children with CKD or chronic renal failure (CRF).

Materials and Methods:

In this analytic-experimental study children aged 3-18 years with a diagnosis of CRF and a group of healthy children were enrolled. Vitamin C (250 mg/day) administrated for the two studied groups for 1 month. Endothelial function was evaluated by FMD and IMT measurement using vascular Doppler ultrasonography, before and after trial.

Results:

In this study 18 patients with CRF and 19 normal children as the control group were studied. At baseline mean of IMT and FMD was not different in the two studied groups (P > 0.05). After vitamin C administration IMT decreased significantly in the two studied groups (P < 0.05). FMD increased in the two studied groups but the difference was significant in the control group (P < 0.05).

Conclusion:

The findings of this interventional trial have demonstrated that vitamin C could have protective effect on ED of patients with CRF possibly in those with severe form of the disease but for obtaining more conclusive results larger sample size is needed.

Influence of Malondialdehyde and Matrix Metalloproteinase-9 on Progression of Carotid Atherosclerosis in Chronic Renal Disease with Cardiometabolic Syndrome

Objective was to assess whether the concentration of malondialdehyde (MDA) as a marker of lipid peroxidation and serum concentration of matrix metalloproteinase-9 (MMP-9) are involved in the process of atherosclerosis in chronic kidney disease (CKD) patients nondialysis-dependent and those on peritoneal dialysis (PD), both with signs of cardiometabolic syndrome (CMS). Thirty CKD and 22 PD patients were included in a study. All observed patients were divided into three subgroups depending on the degree of atherosclerotic changes in the carotid arteries (CA). Severity of atherosclerotic changes in the CA was evaluated by ultrasonography. We confirmed significantly lower level of serum MDA throughout all the stages of atherosclerosis in PD patients compared with observed CKD patients (P < 0.05) and increased serum concentration of MDA and MMP-9 with the progression of severity atherosclerotic changes in both groups of patients. The multiple regression analysis revealed that MDA and MMP-9 are significant predictors of changes in IMT-CA CKD patients (P < 0.05) and plaque score on CA in these patients (P < 0.05). The results suggest that MDA and MMP-9 could be mediators of CKD-related vascular remodeling in CMS.

Impact of peritoneal dialysis treatment on arterial stiffness and vascular changes in diabetic type 2 and nondiabetic patients with end-stage renal disease

Diabetes mellitus (DM) is the leading cause of the end-stage renal disease (ESRD). Vascular diseases are the most common cause of morbidity and mortality in the chronic kidney disease. The aim of this study was to analyze the impact of peritoneal dialysis (PD) treatment on morphologic and hemodynamic vascular parameters of carotid arteries in diabetic type 2 and nondiabetic patients with ESRD during the period of one year after the start of PD treatment using ultrasonography of carotid arteries and their relation on uremia and PD inherent factors. Mean intima-media thickness, plaque score, peak systolic velocity, end-diastolic velocity, and carotid diameter significantly decreased 12 months after PD treatment start in both groups. Significant reduction in median serum endothelin-1 concentration after 12 months on PD treatment was observed in the group of patients with DM (7.6–5.9 pg/mL) and also in group of patients without DM (3.6–3.3 pg/mL). Also median nitric oxide concentration significantly increased after 12 months on PD compared to baseline levels both in patients with DM (25.0–34.3 μmol/L) as was observed in patients without DM (49.6–56.5 μmol/L). PD treatment, with the regulation of these vasoactive molecules and other vascular risk factors, significantly contributes to vascular remodeling, especially in DM patients.