Effect of haemodialysis on the oxidative stress and antioxidants in diabetes mellitus

The Effect of the Hydroalcoholic Extract of Watercress on the Levels of Protein Carbonyl, Inflammatory Markers, and Vitamin E in Chronic Hemodialysis Patients

Introduction

Chronic kidney disorder is a main public health concern. Inflammatory processes and oxidative stress are common in end-stage renal disease patients. We aimed to evaluate the effect of the hydroalcoholic extract of watercress (WC) on the inflammatory cytokines and protein carbonyl (PCO) contents in chronic hemodialysis patients.

Methods

This was a double-blind randomized clinical trial performed on 46 hemodialysis patients. The participants were randomly divided into two groups: intervention group (500 mg hydroalcoholic extract of WC every day for 4 weeks) and control group (500 mg of white flour every night for 4 weeks). The blood samples were taken to determine the levels of vitamin E, PCO, and inflammatory cytokines at baseline and the end of treatment.

Results

Forty-five patients completed the study (22 patients in the intervention group and 23 patients in the control group). There was a significant reduction in the PCO level (20.33 ± 4.40 vs. 15.06 ± 6.41, P=0.001) in the intervention group; also, this change was statistically significant relative to the control group. Furthermore, there were significant reductions in hs-CRP (8953.30 ± 5588.06 vs. 7249.86 ± 5091.62, P=0.007) and IL-6 (60.10 (55.99, 73.10) vs. 55.21 (53.39, 60.48), P=0.050) in the intervention group, but these changes were not significant in comparison with the control group.

Conclusion

We conclude that the hydroalcoholic extract of WC reduced the PCO content in hemodialysis patients via inhibition of protein oxidation. Although WC administration had caused a significant reduction in IL-6 and CRP levels, these differences were not statistically significant relative to the control group. Further research is needed to identify the antioxidant and anti-inflammatory effects of WC in hemodialysis patients.

Effect of uremic serum on Th17/Treg cell balance and endoplasmic reticulum stress in rats

BACKGROUND/AIMS

The imbalance of T helper 17 (Th17) and regulatory T (Treg) cells exists in the occurrence and development of various diseases. Endoplasmic reticulum stress (ERS) is an important self-protective cellular response to harmful stimuli, such as uremic environment. The objective of this study was to investigate the Th17/Treg cell balance and ERS in a uremic environment and analyze the relationship between them.

METHODS

(1) The rat spleen lymphocytes were extracted and treated with thapsigargin (inducer of ERS) and sodium citrate. The proportion of Th17 and Treg cells were then detected. (2) The uremic serum-cultured lymphocytes were used and divided into three groups: non-uremic serum group, uremic serum group, and uremic serum + sodium citrate group. Afterward, the proportion of Th17/Treg cells and the expression of ERS-related proteins (GRP78 and CHOP) were detected.

RESULTS

Thapsigargin had no significant effect on the proportion of Th17 cells within a limited concentration range, but it could reduce the proportion of Treg cells, sodium citrate had a negative influence on the deviation of Th17/Treg cells treated with thapsigargin. Uremic serum treatment reduced the proportion of Treg cells, resulting in an increase of the Th17/Treg ratio. However, sodium citrate had no influence on the deviation of Th17/Treg cells treated by uremic serum. Sodium citrate reduced the elevation of ERS-related proteins induced by uremic serum.

CONCLUSIONS

Uremic serum can lead to the imbalance of Th17/Treg cells as well as ERS, suggesting that ERS is one of the mechanisms of the imbalance of Th17/Treg cells induced by uremic serum. Sodium citrate can inhibit ERS induced by uremic serum.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin–angiotensin–aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water–electrolyte and acid–base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

Serum levels of protein carbonyl, a marker of oxidative stress, are associated with overhydration, sarcopenia and mortality in hemodialysis patients

Background

Increased oxidative stress in end-stage renal disease is regarded as one of the important mechanisms in the atherosclerosis and muscle wasting. However, studies examining the clinical significance of oxidative stress by direct measurement of these markers and its association with volume status and sarcopenia are limited.

Methods

A follow-up cross-sectional study was performed in stable hemodialysis (HD) patients and serum protein carbonyl levels were measured as a biomarker of oxidative stress. Additionally, multi-frequency body composition analysis, handgrip strength (HGS) and nutritional assessments were performed at baseline.

Results

Eighty-eight patients undergoing HD were included and 30 (34.1%) patients died during a mean follow-up of 5.2 years. The mean patient age was 60.6 ± 13.5 years, and the mean HD duration was 50.8 ± 41.3 months. In total, 16 patients (18.2%) were overhydrated, 49 (55.7%) had low HGS and 36 (40.9%) had low muscle mass. Serum protein carbonyl levels were associated with serum levels of albumin, prealbumin and transferrin, hydration status and low HGS. Overhydration (odds ratio [OR] 7.01, 95% CI 1.77–27.79, p = 0.006), prealbumin (OR 0.91, 95% CI 0.83–0.99, p = 0.030), subjective global assessment (OR 3.52, 95% CI 1.08–11.46, p = 0.037) and sarcopenia (OR 3.41, 95% CI 1.02–11.32, p = 0.046) were significantly related to increased serum protein carbonyl levels. Multivariate analysis showed that the serum levels of protein carbonyl (Hazard ratio [HR] 2.37, 95% CI 1.02–5.55, p = 0.036), albumin (HR 0.17, 95% CI 0.06–0.46, p = 0.003), prealbumin (HR 0.86, 95% CI 0.80–0.92, p = 0.001), overhydration (HR 2.31, 95% CI 1.26–8.71, p = 0.015) and sarcopenia (HR 2.72, 95% CI 1.11–6.63, p = 0.028) were independent determinants of all-cause mortality.

Conclusions

Serum protein carbonyl was significantly associated with overhydration, nutritional status and sarcopenia, and could be a new predictor of mortality in patients undergoing HD.

Plasma Protein Carbonylation in Haemodialysed Patients: Focus on Diabetes and Gender

Patients with end-stage renal disease (ESRD) undergoing haemodialysis (HD) experience oxidative/carbonyl stress, which is postulated to increase after the HD session. The influence of diabetes mellitus and sex on oxidation of plasma proteins in ESRD has not yet been clarified despite that diabetic nephropathy is the most common cause of ESRD in developed and developing countries and despite the increasingly emerging differences between males and females in epidemiology, pathophysiology, clinical manifestations, and outcomes for several diseases. Therefore, this study aimed to evaluate the possible effect of type 2 diabetes mellitus, gender, and dialysis filter on plasma level of protein carbonyls (PCO) in ESRD patients at the beginning and at the end of a single HD session. Results show that mean post-HD plasma PCO levels are significantly higher than mean pre-HD plasma PCO levels and that the type of dialysis filter and dialysis technique are unrelated to plasma PCO levels. The mean level of plasma PCO after a HD session increases slightly but significantly in nondiabetic ESRD patients compared to diabetic ones, whereas it increases more markedly in women than in men. These novel findings suggest that women with ESRD are more susceptible than men to oxidative/carbonyl stress induced by HD.

Oxidative stress in the optic nerve and cortical visual area of steptozotocin-induced diabetic Wistar rats: Blockade with a selective bradykinin B1 receptor antagonist

The role of bradykinin B₁ receptors on the oxidative stress as measured by the levels of Na+/K+ ATPase activity, malondialdehyde (MDA) and glutathione (GSH) in male Wistar rat optic nerve and visual cortex area 1 and 4weeks after STZ treatment was studied. Rats were divided into 4 groups (n=6-7): 1. Controls (non-diabetics); 2. Diabetics (65mg/kg streptozotocin, STZ); 3. Diabetics injected with B₁ antagonist R-954 (2mg/Kg) during the last 3days of a one week period; 4. Diabetics injected with B₁ antagonist R-954 (2mg/Kg) during the last 3days of a 4week period. The results showed that plasma glucose levels increased by up to 4 fold in diabetic rats 1 or 4weeks following the STZ treatment. R-954 treatment did significantly decrease blood glucose levels. Levels of MDA was increased in the plasma of the 1 and 4week diabetic animals whereas the GSH levels were decreased. Both markers returned to normal following R-954 treatment. Na+/K+ ATPase activity significantly decreased in the optic nerve and visual cortex of diabetic rats at 1 and 4weeks but returned to normal following R-954 treatment. MDA levels increased markedly at 1 and 4weeks compared with control levels in the optic nerve but slightly in the visual cortex and returned to control levels in both tissues following R-954 treatment. GSH levels decreased in both tissues at 1 and 4weeks compared with control levels. Following administration of the selective BKB₁R antagonist R-954, the levels of GSH returned to normal in both tissues of the 1 and 4week diabetic animals. These results showed that the inducible BKB₁ receptors are associated with the oxidative stress in the optic nerve and cortical visual area of diabetic rats and suggested that BKB₁-R antagonist R-954 could have a beneficial role in the treatment of diabetic retinopathy.

Selenylation of Polysaccharide from the Sweet Potato and Evaluation of Antioxidant, Antitumor, and Antidiabetic Activities

Interest in sweet potato as a functional food is growing. A polysaccharide (SWP) was isolated from the sweet potato tuber and elucidation of its structure as composed of rhamnose, glucose, and galactose undertaken. To improve its activity, selenylation of this novel polysaccharide (Se-SWP) was undertaken by using microwave synthesis. In vitro evaluation showed that the Se-SWP has excellent antioxidant activity on scavenging free radicals and reducing capacity. In vivo antitumor evaluation showed selenylation polysaccharide could effectively inhibit tumor growth (>50%) and adjust immune factor levels in the mice (IL-2, TNF-α, and VEGF). The antidiabetic potential of Se-SWP was tested in STZ-induced diabetic rats. The results indicated that the Se-SWP treatment significantly reduced the levels of malondialdehyde and other disadvantageous factors that were increased by the STZ treatment. Meanwhile, the Se-SWP treatment caused a significant increase in the activities of enzymatic antioxidants and the levels of nonenzymatic antioxidants in the organs of diabetic rats. All of the activity evaluations indicated that the selenylation method could improve the activity of sweet potato polysaccharide and its efficacy as a potential therapeutic, which will be the focus of further study.

Acute blood glucose fluctuation enhances rat aorta endothelial cell apoptosis, oxidative stress and pro-inflammatory cytokine expression in vivo

Background

Complications of diabetes mellitus (DM) are related not only to elevated plasma glucose, but also plasma glucose fluctuations. However, the specific mechanism underlying the role of plasma glucose fluctuation in the pathogenesis of DM complications remains poorly understood. In the present study, the influence of acute fluctuant hyperglycemia and persistent hyperglycemia on vascular endothelial cell apoptosis, function, oxidative stress and inflammation was examined in vivo.

Methods

Rats were assigned to three different groups (n = 10/group) that received 48-h infusions of saline (SAL group), continuous 50 % glucose (constant high glucose group [CHG]), or intermittent 50 % glucose (acute blood glucose fluctuation group [AFG]). Plasma 8-isoprostaglandin, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) levels were quantified by using enzyme-linked immunosorbent assay (ELISA) commercial kits. Plasma insulin levels were measured by radioimmunoassays (RIAs) using kits. The aortic segment was collected. The levels of malondialdehyde (MDA) and activity of glutathione peroxidase (GSH-PX) were measured in endothelial homogenates prepared from endothelial cells harvested from the aorta using colorimetric kits. Apoptosis of vascular endothelial cells was determined with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Endothelial dysfunction was assessed by isometric tension recording to evaluate the endothelial function. The expression of B cell lymphoma-2 (Bcl-2), Bcl-2 Associated X protein (Bax), pro caspase-3, caspase-3 p17, 3-nitrotyrosine (3-NT) and p47phox protein in rat aortic endothelial cells were tested with Western blot analysis. Endothelial cells reactive oxygen species (ROS) formation was determined using dihydroethidium-dependent fluorescence microtopography in aortic cryo-sections. Expression of IL-6, TNF-α and ICAM-1 mRNAs in vascular endothelial cells were determined by real-time quantitative PCR.

Results

Endothelial cells apoptosis and dysfunction were observed significantly in the aortas of the AFG group (P < 0.05). The AFG had reduced Bcl-2 and pro caspase-3 levels and enhanced Bax mitochondrial translocation and caspase-3 p17 protein levels in comparison with the CHG group (P < 0.05). Both AFG and CHG induced β-cell dysfunction and insulin resistance (P < 0.05). AFG increased MDA and 8-isoprostaglandin levels in plasma, oxidative stress in vascular endothelial cells, and inflammatory cytokines in plasma and vascular endothelial cells (P < 0.05).

Conclusion

Acute glucose fluctuation may cause significant oxidative stress and inflammation in endothelial cells, increase the adhesion of monocytes to endothelial cells, and elevate endothelial cell apoptosis, resulting in severe cardiovascular injury.

Influence of Hemodialysis on Lipid Peroxidation, Enzymatic and Non-Enzymatic Antioxidant Capacity in Chronic Renal Failure Patients

BACKGROUND

Free radical induced damages are thought to be involved in chronic kidney disease (CKD), especially in patients who are on hemodialysis (HD) for prolonged periods. Hemodialysis can influence multiple biochemical factors, several of which are useful, although the rest can be harmful and increase the severity of disease.

OBJECTIVES

The purpose of this study was to evaluate the effect of the HD membrane polysulfone on oxidative stress markers, by measuring the level of lipid peroxidation and total antioxidant activity (TAC), in the blood of HD patients.

PATIENTS AND METHODS

This study was carried out on 31 HD patients and 31 healthy persons, matched for age and sex, as control group. Blood samples were drawn before and after HD from arteriovenous fistulas, and once from the controls. Superoxide dismutase (SOD), catalase (CAT) and thiobarbituric acid-reactive substance (TBARS) in blood hemolyzate, Glutathione peroxidase (GpX) of whole blood and TAC of plasma were measured, respectively. Then, we investigated the association between TAC of plasma, measured by ferric reducing antioxidant power (FRAP), and lipid peroxidation level with its related parameters, in HD patients.

RESULTS

The SOD, GpX and CAT were decreased after HD (P < 0.05). Also, FRAP was shown to decrease after HD (P < 0.05). However, erythrocyte TBARS levels (μmol/gr of Hb) were increased after HD, in comparison with controls, and before HD (P < 0.05). There was a significant negative correlation between TBARS and antioxidant indices, such as SOD (r = -0.67, P = 0.001), GpX (r = -0.76, P = 0.001), CAT (r = -0.63, P = 0.001) and FRAP (r = -0.84, P = 0.001). The FRAP was significantly and directly correlated with uric acid (r = +0.62, P = 0.001), SOD (r = +0.72, P = 0.001), GpX (r = +0.87, P = 0.001) and CAT (r = +0.84, P = 0.001).

CONCLUSIONS

The results of our study proposed that there is a loss or inactivation of antioxidant factors, coupled with increased lipid peroxidation during the procedure of HD, possibly through the dialyzer membrane, with probable consequences on the severity of illness.

Advanced oxidation protein products and ischaemia-modified albumin in obstructive sleep apnea

BACKGROUND

Several studies have shown that obstructive sleep apnea increases incidence of cardiovascular morbidity and mortality. The high systemic oxidative stress in obstructive sleep apnea has been considered as a major pathogenic mechanism leading to cardiovascular disease. Oxidative stress-related lipid and DNA oxidation in obstructive sleep apnea have been reported in the previous studies. In contrast, there is limited and contradictory information regarding protein oxidation in obstructive sleep apnea patients such as ischaemia-modified albumin and advanced oxidation protein products. Therefore, we aimed to investigate plasma ischaemia-modified albumin and advanced oxidation protein products and their correlation with total oxidative status and total antioxidative capacity in the obstructive sleep apnea patients.

METHODS

Plasma ischaemia-modified albumin, advanced oxidation protein products, total oxidative status and total antioxidative capacity were measured in 25 healthy volunteers and 59 obstructive sleep apnea patients diagnosed with polysomnography.

RESULTS

Plasma total antioxidative capacity was significantly lower (P = 0·012) and total oxidative status was significantly higher (P < 0·001) in the patients compared to the controls demonstrating increased oxidative stress in the patients. Plasma advanced oxidation protein products were significantly higher in the patients than the controls (P = 0·024). Plasma ischaemia-modified albumin levels were not statistically different between the obstructive sleep apnea patients and controls (P = 0·74).

CONCLUSIONS

We conclude that high systemic oxidative stress in obstructive sleep apnea is reflected by increased advanced oxidation protein products without causing an increase in ischaemia-modified albumin.

Hypoxia and oxidative stress markers in pediatric patients undergoing hemodialysis: cross section study

Background

Tissue injury due to hypoxia and/or free radicals is common in a variety of disease processes. This cross-sectional study aimed to investigate effect of chronic kidney diseases (CKD) and hemodialysis (HD) on hypoxia and oxidative stress biomarkers.

Methods

Forty pediatric patients with CKD on HD and 20 healthy children were recruited. Plasma hypoxia induced factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) were measured by specific ELISA kits while, total antioxidant capacity (TAC), total peroxide (TPX), pyruvate and lactate by enzymatic/chemical colorimetric methods. Oxidative stress index (OSI) and lactate/pyruvate (L/P) ratio were calculated.

Results

TAC was significantly lower while TPX, OSI and VEGF were higher in patients at before- and after-dialysis session than controls. Lactate and HIF-1α levels were significantly higher at before-dialysis session than controls. Before dialysis, TAC and L/P ratio were lower than after-dialysis. In before-dialysis session, VEGF correlated positively with pyruvate, HIF-1α and OSI correlated positively with TPX, but, negatively with TAC. In after-dialysis session, HIF-1α correlated negatively with TPX and OSI; while, OSI correlated positively with TPX.

Conclusions

CKD patients succumb considerable tissue hypoxia with oxidative stress. Hemodialysis ameliorated hypoxia but lowered antioxidants as evidenced by decreased levels of HIF-1α and TAC at before- compared to after-dialysis levels.

Ischemia modified albumin and carbonyl protein as potential biomarkers of protein oxidation in hemodialysis

OBJECTIVE

The aim of this study was to evaluate the effect of HD on ischemia modified albumin (IMA) and protein carbonyl groups in order to investigate the role of IMA as a marker of protein oxidation.

DESIGN AND METHODS

This study was conducted with 23 chronic hemodialysis patients. The serum IMA levels and protein carbonyl groups were measured immediately before hemodialysis (pre-HD) and after the end of hemodialysis (post-HD).

RESULTS

IMA concentrations were significantly higher in post-HD than those of the pre-HD and carbonyl protein concentrations were higher in post-HD in comparison with pre-HD. A significant correlation was observed between IMA and carbonyl protein levels.

CONCLUSIONS

The increase of IMA levels and protein carbonyl groups post-HD could be attributed to the increase of oxidative stress associated with HD, and IMA appears to be an important biomarker for assessing protein oxidation after HD.

Adsorption and carbonylation of plasma proteins by dialyser membrane material: in vitro and in vivo proteomics investigations

BACKGROUND

Protein carbonylation is an irreversible and not reparable reaction which is caused by the introduction into proteins of carbonyl derivatives such as ketones and aldehydes, generated from direct oxidation processes or from secondary protein reaction with reactive carbonyl compounds. Several studies have demonstrated significantly increased levels of reactive carbonyl compounds, a general increase in plasma protein carbonyls and carbonyl formation on major plasma proteins in blood from uremic patients, particularly those undergoing chronic haemodialysis.

MATERIALS AND METHODS

In the present preliminary study, we first assessed by an in vitro filtration apparatus the possible effects of different materials used for haemodialysis membranes on protein retention and carbonylation. We employed hollow fiber minidialyzers of identical structural characteristics composed of either polymethylmethacrylate, ethylenevinyl alcohol, or cellulose diacetate materials. Protein Western Blot and SDS-PAGE coupled to mass spectrometry analysis were applied to highlight the carbonylated protein-binding characteristics of the different materials. We also investigated in vivo protein carbonylation and carboxy methyl lisine-modification in plasma obtained before and after a haemodialysis session.

RESULTS

Our data underline a different capability on protein adsorption associated with the different properties of the filter materials, highlighting the central buffering and protective role of serum albumin. In particular, polymethylmethacrylate and cellulose diacetate showed, in vitro, the highest capacity of binding plasma proteins on the surface of the hollow fiber minidialyzers.

CONCLUSIONS

The present study suggests that biomaterials used for fabrication of haemodialysis membrane may affect the carbonyl balance in chronic uremic patients.

Prediction of diabetic retinopathy: role of oxidative stress and relevance of apoptotic biomarkers

Diabetic retinopathy (DR) is the foremost cause of blindness in working-aged worldwide; it is characterized by vascular and neuronal degeneration. Features of DR include leukocyte adhesion, increased vascular permeability, neovascularization and neuronal cell death. Early diagnosis and intervention are important to prevent or at least ameliorate the development of DR. Recent reports indicate that pathophysiological mechanisms leading to diabetic retinopathy include oxidative stress and retinal cell death cascades. Circulating biomarkers of oxidative stress such as malondialdehyde (MDA), thiobarbituric acid reacting substances (TBARS), conjugated diene (CD), advanced oxidation protein products (AOPP), protein carbonyl, 8-hydroxydeoxyguanosin (8-OHdG), nitrotyrosine, and F(2) isoprostanes and pro-apoptosis molecules (caspase-3, Fas, and Bax) are associated with increased susceptibility to develop DR in diabetic subjects. Thus, identification of oxidative stress and cell death biomarkers in diabetic patients could be in favor of predicting, diagnosis, and prevention of DR, and to target for novel therapeutic interventions.

Oxidative stress parameters as possible urine markers in patients with diabetic nephropathy

OBJECTIVE

Reactive oxygen species play a crucial role in the pathogenesis of diabetic nephropathy (DN). The present study was performed to assess oxidative stress parameters-thiobarbituric acid reactive substances (TBARS), reactive carbonyl derivates (RCDs), and total sulfhydryl groups (TSHGs)-in serum and urine of patients with DN.

METHODS

All parameters were determined in patients with type 2 and type 1 diabetes mellitus and microalbuminuria (DMT2-MIA, DMT1-MIA, respectively) and patients with type 2 diabetes mellitus and macroalbuminuria (DMT2-MAA) compared to healthy controls.

RESULTS

Serum and urine TBARS levels were higher in all patients with DN and microalbiminuria compared to the control group. RCD levels significantly increased in serum of patients with DMT2 relative to the controls as well as in urine of patients with DMT2-MAA and DMT1-MIA. In all groups of patients, TSHGs decreased in serum but not in urine of patients with DMT2-MAA.

CONCLUSION

Urine TBARS, RCDs, and TSHGs could be proposed as possible markers for oxidative damage of kidney in DN.

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

OBJECTIVE

Both diabetes and hemodialysis (HD) are associated with increased oxidative stress. The aim of this study was to clarify the effect of maintenance HD on oxidative stress parameters in diabetic patients and to explore any relation between carotid artery intima-media thickness (CIMT) and oxidative stress markers.

METHODS

Twenty Type 2 diabetic patients undergoing chronic maintenance HD, 20 type 2 diabetic patients with normal renal function, and 20 age- and sex-matched healthy subjects were included. Serum thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCO), and nitrite/nitrate levels were determined as oxidative stress markers. Serum vitamin E, plasma sulfhydryl (P-SH), erythrocyte glutathione (GSH) levels, and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were measured as antioxidants. CIMT was assessed by carotid artery ultrasonography.

RESULTS

Both diabetic patient groups had enhanced oxidative stress indicated by higher levels of TBARS, PCO, and nitrate/nitrite and lower activities of SOD, CAT, and GPx compared to controls. Diabetic patients undergoing HD had significantly higher CIMT (P=.001) and higher levels of nitrite/nitrate (P=.05), PCO (P=.03), and GSH (P=.04) but significantly lower levels of P-SH (P<.001), serum vitamin E (P=.04), SOD (P=.02), CAT (P=.001), and GPx (P=.006) compared to diabetic patients with normal renal functions. There were significant negative correlations between CIMT and SOD (r=-0.50, P<.001), CAT (r=-0.41, P=.003), and P-SH levels (r=-0.51, P<.001) and significant positive correlation between CIMT and nitrite/nitrate levels (r=0.41, P=.003) and TBARS (r=0.35, P=.02). Linear regression analysis showed TBARS was significantly and positively correlated with CIMT (P=.04), while SOD and P-SH were significantly and negatively correlated with CIMT (P=.05 and P=.02, respectively).

CONCLUSIONS

Hemodialysis exacerbates oxidative stress and disturbances in antioxidant enzymes in diabetic patients. Serum nitrite/nitrate and TBARS can be used as positive determinants, while erythrocyte SOD, CAT activities, and P-SH level can be used as negative determinants of atherosclerosis assessed by CIMT in diabetic patients.

[Significance of metal ion metabolism and oxidative stress in male patients with porphyria cutanea tarda]

In the last decades, the role of oxidative stress and trace elements was proven to play an important role in the pathogenesis of more and more diseases. This is why a great importance is attributed lately to the antioxidant therapy, and lots of studies are dealing with this issue. In porphyria cutanea tarda (PCT) the biosynthesis of hem is damaged, because of the reduced activity of uroporphyrinogen-decarboxylase enzyme. The hem precursors are accumulating in blood, liver and skin. The hem precursors and porphyrin are eliminated with urine and stool. The enzyme defect is autosomal dominant. The skin symptoms are intensified by sun exposure. This is because the accumulation of uroporphyrins and heptacarboxylporphyrin in the skin causes photosensitivity, and the accumulated iron has a lipid-peroxidation effect. Besides the genetical origin, the alcohol consumption, the hepatotoxic drugs, estrogen and viral infections can also determine the development of the disease. The applied treatment is phlebotomy. In the case of PCT that appears in the field of liver damage, the accumulation of iron is responsible for the development of oxidative stress. The patient's redox homeostasis is changed, and the level of antioxidants is decreased. The redox state of liver and the effects of additional antioxidant treatment in phlebotomized PCT patients were determined by biochemical and trace element analytical methods. According to the clinical data, phlebotomy proved to be an effective treatment in PCT patients. Phlebotomy improved the phototoxic skin symptoms, but it did not improve the ratios of trace elements to each other in the blood of the patients.

Effect of Age, Gender, and Diabetes on Excess Death in End-Stage Renal Failure

Life expectancy is short in elderly individuals with end-stage renal failure (ESRF). This study aimed to compare mortality in patients with ESRF versus the general population (GP) to assess the evolution of excess mortality by age, gender, nephropathy, and dialysis modality after first dialysis. All incident adult dialysis patients from January 1,1999, to December 31, 2003, who lived in Rhône-Alpes Region (France) were included and followed up to death or December 31, 2005. Standardized mortality ratios (SMR) in comparison with GP were computed in the first to the fifth years after first dialysis. In the whole cohort (3025 incident patients), SMR decreased during these 5 yr from 7.4 to 5.2 (P = 0.002). In the 18- to 44-, 45- to 64-, 65- to 74-, 75- to 84-, and > or =85-yr-old groups, SMR decreased from 26.7 to 6.2 (P = 0.01), from 12.8 to 8.1 (P = 0.03), from 8.6 to 5.6 (P = 0.051), from 7.1 to 4.5 (P = 0.02), and from 3.5 to 1.2 (P = 0.14), respectively. Among age categories, differences were significant in the first 3 yr (P < 0.05). SMR were higher 1.5-fold in women than in men in the first 4 yr (P < 0.05). In patients with diabetic nephropathy (DN), SMR increased during the first 3 yr (P = 0.045) and were higher than in patients without DN in the second, third, and fourth years (P < 0.05). SMR were higher in the peritoneal dialysis than in the hemodialysis group in the fourth year (P < 0.01). Patients with ESRF have a high excess mortality compared with the GP. Older patients with ESRF experienced less excess mortality. ESRF cancels out women's survival advantage noted in the GP. SMR evolution in patients with DN was different from that in patients without DN.

Eucommia ulmoidesOliver Leaf Extract Increases Endogenous Antioxidant Activity in Type 2 Diabetic Mice

Eucommia ulmoides Oliver (Du-zhong) leaf extract was investigated for its antioxidant effects in type 2 diabetic animals, C57BL/KsJ-db/db mice. Du-zhong extract equivalent to 1% dried whole Du-zhong leaf (0.187 g of extract/100 g of diet) was added to the experimental diets for 6 weeks. The Du-zhong extract supplement significantly lowered blood glucose concentrations and elevated plasma paraoxonase activity compared with the control group. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were significantly higher in the Du-zhong group compared with the control group, while glutathione reductase (GR) activity was not different between groups. The activities of SOD, GSH-Px, and GR in liver and kidney were not affected by Du-zhong extract supplementation, whereas the CAT activity was significantly higher in the Du-zhong group than in the control group. Du-zhong extract supplementation resulted in lower levels of hydrogen peroxide and lipid peroxide in erythrocytes, liver, and kidney. These results suggest that the antioxidant activity of Du-zhong extract is potentially beneficial for the prevention and management of complications of type 2 diabetes.