The effect of hemodialysis on accelerated atherosclerosis in diabetic patients: correlation of carotid artery intima-media thickness with oxidative stress

Biological Antioxidant Potential Negatively Correlates With Carotid Artery Intima-Media Thickness

Oxidative stress is a crucial factor in the pathogenesis and development of cardiovascular disease. Recently, simplified methods for the detection of reactive oxygen species (ROS) using the derivatives of reactive oxygen metabolites (d-ROMs) test as an index of ROS products and the biological antioxidant potential (BAP) test as an index of antioxidant potential have been utilized. These methods are easy to perform, quick, inexpensive since they use small equipment, and provide reliable results compared with established oxidative stress and antioxidant markers. Because oxidative stress has been shown to represent the balance of production of ROS and antioxidant capacity, it is more appropriate to evaluate ROS and antioxidant capacity simultaneously. However, no study has examined the associations among d-ROMs, BAP values, and carotid artery intima-media thickness (IMT) concurrently. Therefore, we studied the associations among d-ROMs, BAP values, and the carotid artery IMT. Carotid artery IMT, blood pressure (BP), fasting circulating d-ROMs, BAP, glucose metabolism, lipid, and C-reactive protein levels were measured in 95 subjects (age: 49.5 ± 13.8 years; men: 41; women: 54), including 42 healthy subjects and 53 patients with hypertension, dyslipidemia, and diabetes mellitus who were not on medication. The results of multiple regression analysis revealed that dependent carotid artery IMT determinants remained significantly associated with age, systolic BP, total cholesterol, and BAP, whereas dependent BAP determinants remained significantly associated with body mass index and carotid artery IMT. BAP was strongly correlated with carotid artery IMT in our cohort. Our results suggest that BAP may be a useful risk marker for carotid atherosclerosis.

Association of Plasma Adiponectin and Oxidized Low-Density Lipoprotein with Carotid Intima-Media Thickness in Diabetic Nephropathy

AIMS

We sought to determine the association between levels of adiponectin and oxidized low-density lipoprotein (ox-LDL) in patients with diabetic nephropathy as well as their effect on carotid intima-media thickness (cIMT).

METHODS

Adiponectin and ox-LDL were determined in 25 diabetic patients without nephropathy and 94 patients at different stages of diabetic nephropathy including subjects on hemodialysis. cIMT was measured using real-time B-mode ultrasonography.

RESULTS

Plasma adiponectin levels increased significantly with severity of diabetic nephropathy (P = 0.002), on the contrary to ox-LDL which decreased with disease severity (P < 0.001). cIMT was significantly higher at late stages of diabetic nephropathy compared with early stages (P = 0.022). Adiponectin was a significant negative predictor of ox-LDL levels (β = -5.45, P = 0.023), independently of confounding factors. There was no significant correlation between cIMT and adiponectin or ox-LDL either in the total sample population or according to disease staging. Cluster analysis showed that patients with the highest cIMT values, highest levels of adiponectin, and lowest levels of ox-LDL were included in one cluster and all assigned to stage 5 of diabetic nephropathy.

CONCLUSIONS

There was no significant association between adiponectin or ox-LDL and cIMT and, therefore, other factors affecting this surrogate marker of cardiovascular disease in diabetic nephropathy should be sought.

Relation between carotid intima media thickness and oxidative stress markers in type 1 diabetic children and adolescents

BACKGROUND

Carotid intima media thickness (CIMT) is a non invasive marker of subclinical atherosclerosis. Hyperglycemia, oxidatively modified atherogenic lipoproteins and advanced glycation end products are linked to increased oxidative stress in diabetes. We aimed to find out the relation between carotid intima media thickness in type 1 diabetic children and adolescents and plasma nitric oxide and total antioxidant capacity levels as markers of oxidative stress.

METHODS

This study included 50 children and adolescents with type 1 diabetes mellitus with mean age (9.7 ± 3.4 years) and 50 healthy age and sex matched controls. They were subjected to assessment of hemoglobin A1c, total cholesterol and triglycerides, serum total antioxidant capacity, serum nitric oxide (NO) by colorimetric method and carotid intima media thickness by B-mode ultrasound.

RESULTS

There was significant elevation in serum nitric oxide (17.07 ± 6.4 vs 12.6 ± 4.7 μmol/L; p < 0.001), CIMT (0.47 ± 0.04 vs 0.39 ± 0.02 mm; p < 0.001) and significant reduction in serum total antioxidant capacity (0.41 ± 0.29 vs 0.87 ± 0.23 mmol/L; p < 0.001) in diabetic patients compared to controls. Carotid intima media thickness was correlated positively with nitric oxide (r = 0.402, p = 0.01) and negatively with total antioxidant capacity (r = -0.341, p = 0.02). Carotid intima media thickness was also correlated positively with age, duration of diabetes but not correlated with glycemic control or lipid profile.

CONCLUSION

The significant elevation in nitric oxide and reduction in total antioxidant capacity in children and adolescents with type 1 diabetes mellitus with their correlation with carotid intima media thickness may reflect the role of oxidative stress in the development of atherosclerosis in young type 1 diabetic subjects.

The alteration in Cu/Zn superoxide dismutase and adhesion molecules concentrations in diabetic patients with chronic kidney disease: the effect of dialysis treatment

AIMS

The study investigated the effect of chronic kidney disease (CKD) and renal replacement therapy on diabetes mellitus-mediated alterations in antioxidative defence and in soluble adhesion molecules (sCAMs).

METHODS

We assessed plasma Cu/Zn superoxide dismutase (Cu/Zn SOD) and sCAMs (sICAM-1, sVCAM-1) concentrations by ELISA in diabetic and non-diabetic patients on hemodialysis (HD), continuous ambulatory peritoneal dialysis (CAPD) and on conservative treatment.

RESULTS

All studied parameters were higher in diabetic patients when compared to non-diabetics CKD patients. Cu/Zn SOD and sVCAM-1 were lower in diabetic patients on HD and on CAPD relative to their non-diabetic counterparts. In contrary, sICAM-1 level was grown up in dialyzed diabetic patients relative to the non-diabetic patients. The positive association was between Cu/Zn SOD and sVCAM-1 in each studied group. The inverse relationship was between glycemia and these parameters in CAPD, whereas the positive correlation was observed between glycemia and sICAM-1.

CONCLUSIONS

The coexistence of diabetes mellitus is the important factor for the elevation both antioxidant defence as well as sCAMs in CKD patients. The inception of dialysis treatment can affect Cu/Zn SOD and sVCAM-1 but not sICAM-1 levels in diabetics. Moreover, these data suggest that both antioxidative defence and sCAMs could be regulated in different ways by glycemia.

Differential effects of low-dose fenofibrate treatment in diabetic rats with early onset nephropathy and established nephropathy

We have previously shown that low-dose fenofibrate treatment has an ability to prevent diabetes-induced nephropathy in rats. We investigated here the comparative pre- and post-treatment effects of low-dose fenofibrate (30 mg/kg/day p.o.) in diabetes-induced onset of nephropathy. Rats were made diabetics by single administration of streptozotocin (STZ, 55 mg/kg i.p.). The development of diabetic nephropathy was assessed biochemically and histologically. Moreover, lipid profile and renal oxidative stress were assessed. Diabetic rats after 8 weeks of STZ-administration developed apparent nephropathy by elevating serum creatinine, blood urea nitrogen and microproteinuria, and inducing glomerular-capsular wall distortion, mesangial expansion and tubular damage and renal oxidative stress. Fenofibrate (30 mg/kg/day p.o., 4 weeks) pretreatment (4 weeks after STZ-administration) markedly prevented diabetes-induced onset of diabetic nephropathy, while the fenofibrate (30 mg/kg/day p.o., 4 weeks) post-treatment (8 weeks after STZ-administration) was less-effective. However, both pre-and post fenofibrate treatments were effective in preventing diabetes-induced renal oxidative stress and lipid alteration in diabetic rats though the pretreatment was slightly more effective. Conversely, both pre-and post fenofibrate treatments did not alter elevated glucose levels in diabetic rats. It may be concluded that diabetes-induced oxidative stress and lipid alteration, in addition to a marked glucose elevation, play a detrimental role in the onset of nephropathy in diabetic rats. The pretreatment with low-dose fenofibrate might be a potential therapeutic approach in preventing the onset of nephropathy in diabetic subjects under the risk of renal disease induction. However, low-dose fenofibrate treatment might not be effective in treating the established nephropathy in diabetic subjects.

Asymmetric dimethylarginine: a novel cardiovascular risk factor in end-stage renal disease

OBJECTIVE

This cross-sectional study explored the association between carotid intima-media thickness (CIMT) and the oxidative stress markers asymmetric dimethylarginine (ADMA) and homo cysteine in patients with end-stage renal disease who were on haemodialysis.

METHODS

A total of 30 patients undergoing chronic haemodialysis treatment were recruited to this study. Homocysteine and ADMA levels were determined using a fluorescence polarization immunoassay and an enzyme-linked immunosorbent assay, respectively. CIMT was measured as a marker of atherosclerosis using high-resolution ultrasonography and was performed after haemodialysis.

RESULTS

Significant positive correlations were found between CIMT and ADMA, and CIMT and duration of haemodialysis. Linear regression analysis showed that ADMA level and age were significant independent determinants of CIMT, whereas homo cysteine was not.

CONCLUSIONS

The relationship demonstrated between plasma ADMA and carotid artery thickening suggests that ADMA may be a novel marker of atherosclerosis in patients on haemodialysis.

Genetic variation in GPX1 is associated with GPX1 activity in a comprehensive analysis of genetic variations in selenoenzyme genes and their activity and oxidative stress in humans

Previous studies suggest some effects of selenium on risk of several chronic diseases, which may be mediated through a small number of selenoenzymes with antioxidant properties. In this cross-sectional analysis of 195 participants from the Seattle Barrett's Esophagus Study who were free of esophageal cancer at the time of blood draw, we examined whether the number of the minor alleles in 26 tagging single nucleotide polymorphisms (SNP) of five selenoenzyme genes [i.e., glutathione peroxidase 1-4 (GPX1-4) and selenoprotein P (SEPP1)] was associated with activity of GPX1 in white blood cells and GPX3 in plasma, and concentrations of SEPP1 and markers of oxidative stress [malondialdehyde (MDA) and protein carbonyl content] in plasma. At the gene level, associations were observed between overall variation in GPX1 and GPX1 activity (P = 0.02) as well as between overall variation in GPX2 and SEPP1 concentrations (P = 0.03). By individual SNP, two variants in GPX1 (rs8179164 and rs1987628) showed a suggestive association with GPX1 activity (P = 0.10 and 0.08, respectively) and two GPX2 variants (rs4902346 and rs2071566) were associated with SEPP1 concentration (P = 0.004 and 0.002, respectively). Furthermore, two SNP in the SEPP1 gene (rs230813 and rs230819) were associated with MDA concentrations (P = 0.03 and 0.02, respectively). Overall, our study supports the hypothesis that common genetic variants in selenoenzymes affect their activity.

Endothelial function and oxidative stress in chronic kidney disease of varying severity and the effect of acute hemodialysis

AIM

Oxidative stress (OS) and endothelial dysfunction are implicated in accelerated atherosclerosis in chronic kidney disease (CKD). We assessed endothelial function, OS, and carotid intimal medial thickness (CIMT) and their correlates in 44 CKD stage 5 patients (group III) before and after hemodialysis (HD), 40 patients of CKD stages 3 and 4 (group II), and 25 matched controls (group I).

METHODS

OS was measured by serum concentration of antioxidants; vitamin C and fractional reducing ability of plasma (FRAP) and pro-oxidant; thiobarbituric acid reactive substances (TBARS). Ultrasonography of carotid artery for CIMT and of brachial artery for flow-mediated dilatation (endothelium-dependent dilatation, EDD) was done.

RESULTS

TBARS increased significantly with severity of CKD. Antioxidants FRAP and vitamin C were significantly lower in CKD patients as compared with controls, but there was no significant difference between groups II and III. EDD decreased significantly with severity of CKD, whereas CIMT though higher in CKD patients as compared with controls was not significantly different between groups II and III. After a session of HD as compared with predialysis, levels of TBARS decreased, whereas those of FRAP, vitamin C, and EDD increased. On multivariate analysis, there was negative correlation of TBARS with glomerular filtration rate (GFR), serum albumin, hemoglobin, and EDD. Vitamin C had positive correlations with GFR, serum albumin, hemoglobin, and EDD. EDD had direct correlation with GFR, whereas CIMT correlated negatively with EDD.

CONCLUSIONS

Endothelial dysfunction and OS occur early in CKD, are closely related to each other and structural atherosclerosis, and are proportional to decline in GFR.

The effects of 1-year treatment with a haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) dialysis on biomarkers of oxidative stress in patients with chronic renal failure

In the last few years haemodiafiltration with on-line regeneration of ultrafiltrate (HFR) has been shown to have a positive impact on inflammation and oxidative stress biomarkers, but its effect on antioxidant levels and on oxidative damage to biomolecules in the long-term is still unknown. This is a randomised clinical study over 12 months involving 40 patients on haemodialysis, comparing the effect of HFR (n=25) dialysis with haemodialysis with polysulfone (HD-PS, n=15) on oxidative stress. Total antioxidant capacity, enzymatic antioxidant [superoxide dismutase (SOD), catalase and glutathione peroxidase], non-enzymatic (GSH) and biomarkers of oxidative stress (TBARs, carbonyl groups and 8-OH-dG) were evaluated. The antioxidant activity decreased in the lymphocytes of patients dialysed with HFR, with a significant decrease in the enzyme SOD. In the oxidative stress biomarkers, an increase was seen in the levels of 8-OH-dG in patients on HD-PS dialysis but not in those treated with HFR. Throughout the year the changes in antioxidant levels and biomarkers of oxidative damage in patients dialysed with HFR were generally more modest and fluctuated less than those dialysed with HD-PS. Our study indicates that, in general, long-term dialysis with HFR does not modified antioxidant parameters or increases the oxidative damage to biomolecules. The HFR showed to be a biocompatible technique for long-term dialysis.