Oxidative stress and nitric oxide related parameters in type II diabetes mellitus: effects of glycemic control

Beneficial effect of grape seed proanthocyanidin extract in rabbits with steroid-induced osteonecrosis via protecting against oxidative stress and apoptosis

BACKGROUND

Oxidative damage and apoptosis play dominant roles in the pathogenesis of steroid-induced osteonecrosis (ON). Grape seed proanthocyanidin extract (GSPE) demonstrates antioxidant and antiapoptotic properties. Our aim was to demonstrate the effects of GSPE in preventing steroid-induced ON in rabbits.

METHODS

Osteonecrosis was induced by high-dose methylprednisolone (40 mg/kg). Rabbits in the preventive medicine group were treated with 100 mg/kg/day GSPE for 14 consecutive days, and the presence or absence of ON was examined histopathologically. Oxidative damage in bone tissue was assessed by immunohistochemical staining of 8-oxo-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA) levels, and activities of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and phospholipid hydroperoxide glutathione peroxidase (GSH-Px). Apoptosis was detected via quantitative terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate nick end labelling (TUNEL) staining and activated caspase 3 immunoblotting and activity.

RESULTS

GSPE significantly attenuated the changes of immunohistochemical staining of 8-OHdG, MDA levels, and antioxidant enzymes activities, which were caused by methylprednisolone administration. Quantitative TUNEL and caspase 3 assay showed lower apoptosis with GSPE application. Simultaneously, GSPE reduced the incidence of steroid-induced ON in an established rabbit model to 17.6 %, compared with 87.5 % in the steroid-only group.

CONCLUSION

These results reveal that GSPE treatment could inhibit oxidative damage and apoptosis to exert beneficial effects on reducing the incidence of steroid-induced ON in rabbit models.

Effects of paricalcitol and aliskiren combination therapy on experimental diabetic nephropathy model in rats

BACKGROUND/AIMS

The aim of the present study was to investigate the effect of combination of aliskiren with paricalcitol on experimental diabetic nephropathy (DN) model in rats.

METHODS

Forty male Sprague Dawley rats were divided into 5 groups of 8 rats each, namely the control (Group C), diabetes (Group D), aliskiren (Group A), paricalcitol (Group P), and aliskiren plus paricalcitol (Group A+P) groups. Aliskiren was given by oral-gavage at a dose of 50 mg/kg/day once daily for 12 weeks. Paricalcitol was given by intraperitoneally at a dose of 0,4 µg/kg/three day of week for 12 weeks. Renal function parameters, oxidative stress biomarkers, mRNA expression of renin-angiotensin system parameters and kidney histology were determined.

RESULTS

Group A+P had lower mean albümin-to-creatinine ratio (ACR) (p=0.004) as well as higher creatinine clearance (CCr) (p<0.005) than the diabetic rats (Group D). Combination therapy significantly increased CCr (Group A+P vs. Group A, p<0.005; Group A+P vs. Group P, p=0.022) and reduced ACR (Group A+P vs. Group A, p=0.018; Group A+P vs. Group P, p<0.005) when compared to monotherapy. Serum malondialdehyde levels were significantly lower (p=0.004); glutathion levels (p=0.003), glutathion peroxidase (p=0.004) and superoxide dismutase (p<0.005) activities were significantly higher in group A+P than in group D. The mean scores of mRNA expression of renin (p<0.005), angiotensin II (p=0.012) and angiotensin type 1 receptor (p=0.018) in group A+P were significantly lower. Although combination therapy showed no additional effect on oxidative system, renin-angiotensin system and renal histology, aliskiren plus paricalcitol significantly decreased interstitial fibrosis volume when compared to monotherapy (Group A+P vs. Group A, p<0.005; Group A+P vs. Group P, p=0.002).

CONCLUSION

Our data seem to suggest a potential role of aliskiren plus paricalcitol acting synergystically for reducing the progression of diabetic nephropathy in an experimental rat model.

Viral load is associated with abnormal serum levels of micronutrients and glutathione and glutathione-dependent enzymes in genotype 3 HCV patients

Background

Oxidative stress in hepatitis C patients has been linked to hepatitis C virus. We verified this assumption in HCV genotype 3 patients by detecting the relationship between viral load and certain specific oxidative stress markers like Cu, Mn, Fe, Se, Zn and glutathione and glutathione-dependent enzymes.

Method

Subjects (n = 200, average age 24 years) with quantitative HCV RNA polymerase chain reaction-proven genotype 3 hepatitis C were simultaneously evaluated. Cu, Mn, Fe, Se and Zn serum levels were by using atomic absorption spectrophotometer. Internationally accepted methods were used for viral load quantification of glutathione, GR and Gpx serum levels.

Result

There was a significant correlation between HCV viral load and studied parameters. With the increase of viral load from mild group (200,000–1,000,000 copies/ml) to severe group (5,000,000–25,000,000 copies/ml) the serum levels of Cu, Mn, Zn, and Fe and glutathione reductase were found to be abnormally high. However, in severe viral load group serum concentration of Se and glutathione was less than the healthy controls.

Conclusion

As a significant correlation was detected between the study parameters in genotype 3 HCV patients, it is concluded that the studied micronutrients and glutathione and glutathione-dependent enzymes are the biomolecular targets of HCV to induce oxidative stress.

General significance

Constant monitoring and regulation of the recommended biomolecular targets of HCV can improve the plight of more than 170 million patients suffering from hepatitis C virus around the globe.

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Viral load, micronutrients, antioxidants are key factors involved in oxidative stress.

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We investigated viral load GSH, GPx, GR, Cu, Mn, Zn, Se, and Fe in genotype 3 HCV patients.

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Abnormal levels of GSH, GPx, Gr and micronutrients are linked with the progression of hepatitis C.

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These parameters are associated to immune response, mitochondrial damage and inflammation.

Antioxidant potential of bilirubin-accelerated wound healing in streptozotocin-induced diabetic rats

Oxidative injury is markedly responsible for wound complications in diabetes mellitus. The biological actions of bilirubin may be relevant to prevent oxidant-mediated cell death, as bilirubin application at a low concentration scavenges reactive oxygen species. Hence, we hypothesized that topical bilirubin application might improve wound healing in diabetic rats. Diabetes was induced in adult male Wistar rats, which were divided into two groups, i.e., diabetic control and diabetic treated. Non-diabetic healthy rats were also taken as healthy control group. Wound area was measured on days 3, 7, 14, and 19 post-wounding. The levels of malondialdehyde (MDA) and reduced glutathione (GSH) and the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were estimated in the granulation tissue. There was a significant increase in percent wound closure in healthy control and diabetic treated rats on days 7, 14, and 19, as compared to diabetic control rats on days 7, 14, and 19. There was significant decrease in MDA levels on days 7, 14, and 19 in diabetic treated rats, as compared to diabetic control rats. Levels of GSH were significantly increased on days 3, 7, 14, and 19 in diabetic treated rats, as compared to diabetic control rats. GPx, SOD, and CAT activities were significantly higher on days 3, 7, and 14 in diabetic treated rats, as compared to diabetic control rats. The findings indicate that bilirubin is effective in reducing the oxidant status in wounds of diabetic rats which might have accelerated wound healing in these rats.

Fenugreek Prevents the Development of STZ-Induced Diabetic Nephropathy in a Rat Model of Diabetes

The present study aims to examine the protective effect of fenugreek and the underlying mechanism against the development of diabetic nephropathy (DN) in streptozotocin- (STZ-) induced diabetic rats. A rat model of diabetes was successfully established by direct injection of STZ and then the rats were administered an interventional treatment of fenugreek. Parameters of renal function, including blood glucose, albuminuria, hemoglobin A1c (HbA1c), dimethyl formamide (DMF), blood urine nitrogen (BUN), serum creatinine (Scr), and kidney index (KI), were detected in the three groups (Con, DN, and DF). Oxidative stress was determined by the activity of antioxidase. Extracellular matrix (ECM) accumulation and other morphological alterations were evaluated by means of immunohistochemistry and electron microscope. Quantitive (q)PCR was employed to detect the mRNA expression of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) and protein expression was determined with western blot analysis. DN rats in the present study demonstrated a significant renal dysfunction, ECM accumulation, pathological alteration, and oxidative stress, while the symptoms were evidently reduced by fenugreek treatment. Furthermore, the upregulation of TGF-β1 and CTGF at a transcriptional and translational level in DN rats was distinctly inhibited by fenugreek. Consequently, fenugreek prevents DN development in a STZ-induced diabetic rat model.

Protective Effect of Ethyl Acetate Fraction of Stereospermum Suaveolens Against Hepatic Oxidative Stress in STZ Diabetic Rats

Stereospermum suaveolens is a folk remedy for the treatment of diabetes and liver disorders in southern parts of India. In the present study, the protective effect of the ethyl acetate fraction of ethanol extract from S. suaveolens against hepatic oxidative stress was evaluated in streptozotocin (STZ)-induced diabetic rats for 14 days. The ethyl acetate fraction was administered orally to the STZ diabetic rats at the doses of 200 and 400 mg/kg. Blood glucose level was measured according to glucose oxidase method. In order to determine hepatoprotective activity, changes in the levels of serum biomarker enzymes such as aspartate transaminase (AST), alanine transaminase (ALT), and serum alkaline phosphatase (SALP) were assessed in the ethyl acetate fraction treated diabetic rats and were compared with the levels in diabetic control rats. In addition, the antioxidant activity of ethyl acetate fraction was evaluated using various hepatic parameters such as thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). It was found that administration of ethyl acetate fraction (200 and 400 mg/kg) produced a significant (P < 0.001) fall in fasting blood glucose level, TBARS, bilirubin, AST, ALT, and SALP, while elevating the GSH levels, and SOD and CAT activities in diabetic rats. Histopathologic studies also revealed the protective effect of ethyl acetate fraction on the liver tissues of diabetic rats. It was concluded from this study that the ethyl acetate fraction from ethanol extract of S. suaveolens modulates the activity of enzymatic and nonenzymatic antioxidants and enhances the defense against hepatic oxidative stress in STZ-induced diabetic rats.

Ebselen exhibits glycation-inhibiting properties and protects against osmotic fragility of human erythrocytes in vitro

Diabetic status is associated with an increase on oxidative stress markers in humans and animal models. We have investigated the in vitro effects of high concentrations of glucose on the profile of oxidative stress and osmotic fragility of blood from control and diabetic patients; we considered whether its antioxidant properties could afford some protection against glucose-induced osmotic fragility, and whether ebselen could act as an inhibitor of hemoglobin glycation. Raising blood glucose to 5-100 mmol/L resulted in a concentration-dependent increase of glycated hemoglobin (HbA1c; P < 0.001) and thiobarbituric acid reactive species (TBA-RS) content (P < 0.004). Non-protein SH groups (NPSH) also increased significantly as the concentration of glucose increased up to 30 mmol/L (P < 0.001). The osmotic fragility was more pronounced in blood of uncontrolled diabetic patients than in these non-diabetic subjects. Ebselen significantly reduced the glucose-induced increase in osmotic fragility and inhibited HbA1c formation (P < 0.0001). These results indicate that blood from patients with uncontrolled diabetes are more sensitive to osmotic shock than from patients with controlled diabetes and control subjects in relation to increased production of free radicals in vivo.

Antidiabetic effect of Lactobacillus casei CCFM0412 on mice with type 2 diabetes induced by a high-fat diet and streptozotocin

OBJECTIVE

The aim of this study was to evaluate the antidiabetic effects of Lactobacillus casei CCFM0412 on mice with type 2 diabetes induced by a high-fat diet and streptozotocin.

METHODS

Thirty-two male C57 BL/6 J mice were assigned to four groups in this study. Type 2 diabetes was induced by feeding of a high-fat diet and injection of streptozotocin. L. casei CCFM0412 was administered to mice at a dose of 10(9) cfu/d per mouse for 12 wk. Body weight, fasting and postprandial 2-h blood glucose, oral glucose tolerance, glycosylated hemoglobin, insulin, and glycogen in liver were measured. Endotoxin, tumor necrosis factor-α, and interleukin-10 levels were determined. Lipid metabolic parameters including triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were also measured. The activities of glutathione peroxides, reactive oxygen species, and superoxide dismutase, and the levels of glutathione and malondialdehyde in the liver also were determined. Pancreas injury was evaluated by histologic analysis.

RESULTS

At 13 wk, L. casei CCFM0412 significantly decreased fasting and postprandial 2-h blood glucose, glycosylated hemoglobin, endotoxin, tumor necrosis factor-α, triglycerides, total cholesterol, low-density lipoprotein cholesterol, reactive oxygen species, and malondialdehyde levels compared with the control group (P < 0.05). The values for insulin, interleukin-10, high-density lipoprotein cholesterol, glutathione peroxides, superoxide dismutase, glutathione, and glycogen were significantly increased at 13 wk (P < 0.05). Islets of Langerhans in the L. casei CCFM0412 group were substantially protected from destruction compared with those in the control group.

CONCLUSION

L. casei CCFM0412 significantly improved glucose intolerance, dyslipidemia, immune-regulatory properties, and oxidative stress in mice with type 2 diabetes induced by a high-fat diet and streptozotocin. The results provide a sound rationale for future clinical trials of oral administration of L. casei CCFM0412 for the primary prevention of type 2 diabetes.

Appraisal of in vitro and in vivo antioxidant activity potential of cornelian cherry leaves

The antioxidant activity of the 80% methanolic extract of Cornus mas L. leaves (CMM) was evaluated by various methods both in vitro and in vivo. In vitro screening tests indicated that CMM had high antioxidant activity in terms of free radical scavenging and metal reducing activity. In vivo antioxidant activity studies in normal healthy rats demonstrated that the total antioxidant capacity of liver homogenates were increased, although no changes were observed in the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase or in the level of lipid peroxidation. Studies on CCl4-treated rats also showed that CMM restored the activities of antioxidant enzymes, lowered the level of lipid peroxidation and elevated the total antioxidant capacities of both the total blood and liver homogenates of the animals. Further activity-guided fractionation studies led to the isolation of gallic acid, a well-known antioxidant, as one of the active components.

Effect of glycemic control on soluble RAGE and oxidative stress in type 2 diabetic patients

BACKGROUND

The interaction of advanced glycation end products (AGEs) and its receptor (RAGE) has played an important role in the pathogenesis of diabetes and its complications. A soluble form of RAGE (sRAGE) has been reported as a decoy receptor for AGEs. Oxidative stress is demonstrated in pathological condition such as atherosclerosis and diabetes mellitus. It has been suggested to be involved in the pathogenesis of both macro- and microvascular complications. This study was designed to evaluate the effect of glycemic control on sRAGE and oxidative stress markers in type 2 diabetic patients.

METHODS

Seventy patients with type 2 diabetes and 20 healthy subjects were recruited into the study. Blood glutathione (GSH) and plasma total nitric oxide (NOx) levels were measured using commercially available colorimetric kits, blood superoxide dismutase (SOD) activity was measured by the method of Marklund and Marklund, and plasma C-peptide, oxidized LDL (ox-LDL), sRAGE, and VCAM-1 levels were measured using competitive ELISA kits.

RESULTS

Plasma sRAGE levels were significantly lower (p < 0.05) while VCAM-1 levels were significantly higher (p < 0.05) in poorly controlled diabetic patients compared with healthy control. Blood GSH levels were significantly lower in diabetic patients compared with healthy control (p < 0.05). Plasma C-peptide, NOx, ox-LDL levels, and SOD activity were not significantly different in diabetic patients compared with healthy control. Plasma levels of sRAGE were negatively associated with circulating VCAM-1 levels in diabetic patients.

CONCLUSION

Poor glycemic control decreases plasma sRAGE and increases VCAM-1 levels while good glycemic control improves these abnormalities which provides benefit to diabetic patients.

The effect of chlorpyrifos on isolated thoracic aorta in rats

This study investigated the effect of chlorpyrifos on thoracic aorta and on the level of NO in plasma and aorta. The effect of chlorpyrifos on thoracic aorta in organ bath was determined in 10 rats. Another 45 rats were assigned to 3 groups with 15 rats each: control group 1 received distilled water, control group 2 was given corn oil, and the last group was given 13.5 mg/kg chlorpyrifos dissolved in corn oil every other day for 8 weeks orally. Chlorpyrifos (10⁻¹⁰ M–10⁻⁵ M) showed no effect on isolated thoracic aorta. Plasma AChE activity was decreased, while LDH, ALT, GGT, and AST activities were increased in chlorpyrifos group compared to control groups. Plasma NO level was increased in chlorpyrifos group compared to control groups. iNOS expression was present in all groups in the cytoplasm of the endothelia and in the smooth muscle cells of aorta. According to semiquantitative histomorphological analysis, iNOS immunopositive reactions were seen in the decreasing order in chlorpyrifos, control 2, and control 1 groups. eNOS immunopositive reactions were observed in the endothelial cell cytoplasm, rarely in the subintimal layer, and the smooth muscle cells of aorta. There were no differences among the groups in terms of eNOS immunostaining. In conclusion, chlorpyrifos induced NO production in aorta following an increase in NOS expression.

Profile of oxidant and antioxidant activity in prepubertal children related to age, gender, exercise, and fitness

Tissue damage resulting from oxidative stress induced by a pathological condition might have more serious consequences in children than in adults. Researchers have not yet identified particular markers — alone or in combination with others — of oxidative stress, or their role in pediatric diseases. The aim of this study was to identify gender-based biomarkers for measuring oxidative stress. Oxidative biomarkers were studied in 138 healthy Spanish children (85 boys, 53 girls) 7 to 12 years of age, at the prepubertal (Tanner I) stage, independent of body mass index (BMI), age, fitness (measured by 20-m shuttle run test), and physical activity (measured by participation in an after-school exercise program). The oxidative biomarkers measured were lipid peroxidation products, total nitrites, protein carbonyls, and oxidized glutathione (GSSG). The antioxidant biomarkers measured were total glutathione (TG), reduced glutathione (GSH), superoxide dismutase activity (SOD), and glutathione peroxidase activity. In the study population, height, weight, waist circumference, and BMI were lower in girls than in boys. For oxidative biomarkers, boys had higher levels of protein carbonyl than girls (p < 0.001). In spite of this, girls had higher levels of GSSG (p < 0.001) and TG (p = 0.001), and a lower GSH/GSSG ratio (p < 0.001) than boys. For the antioxidant response, girls had higher levels of SOD (p = 0.002) than boys. All analyses were adjusted for BMI, age, fitness, and physical activity. In conclusion, prepubertal girls had higher oxidative stress than boys, in addition to higher levels of SOD, independent of age, BMI, fitness, and physical activity.

The protective effects of taurine on experimental acute pancreatitis in a rat model

The aim of this study was to investigate the protective effects of taurine (Tau) on experimental acute pancreatitis (AP) in a rat model by measuring cytokines and oxidant stress markers.

Forty rats were randomly divided into four groups: sham, AP, Tau and AP + Tau. AP was induced with sodium taurocholate. No treatment was given to the AP. All rats were killed 5 days later. Pancreatic tissues of rats and blood samples were obtained.

Tau treatment significantly decreased serum amylase activity ( p < 0.001), total injury score ( p < 0.001), malondialdehyde levels ( p < 0.001) and myeloperoxidase (MPO) activity ( p < 0.001). There was no significant difference between the Tau and AP + Tau groups in serum and pancreatic tumor necrosis factor-α, interleukin (IL)-1β and IL-6 levels ( p = 1.000). Histopathologic scores in the AP + Tau and Tau groups were significantly lower compared with the AP group (both p < 0.001).

These results showed that Tau reduces lipid peroxidation, amylase and MPO activities and the concentrations of proinflammatory cytokines secondary to AP and also increases superoxide dismutase and glutathione peroxidase activities in rats with sodium taurocholate-induced AP. It also has a marked ameliorative effect at histopathologic lesions. With these effects, Tau protects the cells from oxidative damage, reduces inflammation and promotes regression of pancreatic damage.

Effect of carnosine on erythrocyte deformability in diabetic rats

It is known that oxidative stress plays an important role in the chronic complications of diabetes. Lipid peroxidation is one of the consequences of oxidative stress. Erythrocyte deformability abilities are reduced as a result of lipid peroxidation. Conversely, a decrease nitric oxide (NO) production seems to be responsible in endothelial dysfunction which occurs in diabetic vascular complications. Carnosine is a molecule with anti-oxidant properties. The aim of this study was to investigate erythrocyte deformability indices and the effects of carnosine on erythrocyte deformability in diabetes and to determine a possible relationship between carnosine and nitric oxide. Male Wistar albino rats were used in the study. Injections were administered to seven groups consisting of eight rats each. The groups were: Control, Carnosine, L-NAME (NG-nitro-L-arginine methyl ester), Diabetic, STZ (Streptozotocin) +Carnosine, STZ+L-NAME and STZ+Carnosine+L-NAME. In addition, glucose, insulin, MDA (Malondialdehyde) and NO levels were measured and erythrocyte deformability indices were calculated in all groups. Erythrocyte deformability indices and NO levels were decreased and MDA levels were found to be increased in diabetic group. It was also found that carnosine can significantly reverse erythrocyte deformability, reduce lipid peroxidation and increase NO levels in diabetes. It can be concluded that carnosine can recover from microvascular circulation problems by increasing erythrocyte deformability, can protect cells and tissues against lipid peroxidation and can be used as a multi-functional anti-oxidant in the treatment of diabetes mellitus to prevent the complications of diabetes.

Risk factors for coronary heart disease in type II diabetes mellitus

Cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. An attempt has been made to evaluate the risk factors for coronary heart disease in type II diabetics. In the present study the levels of fasting and postprandial plasma glucose, total cholesterol, low density lipoproteins, triglycerides were high and the levels of high density lipoproteins were low in the type II diabetics compared to controls. The markers of free radical induced injury i.e. malondialdehyde and nitrite/nitrate were high while total antioxidant status a marker for antioxidant protection against reactive oxygen species was low in diabetics compared to controls. The study therefore suggests the importance of assessing these markers of oxidative stress and antioxidant capacity along with the other routine investigations in diabetic patients for initiating antioxidant therapy in addition to primary and secondary preventive measures to mitigate the devastating consequences of diabetes leading to coronary heart disease.

Parameters of glycemic control and their relationship with zinc concentrations in blood and with superoxide dismutase enzyme activity in type 2 diabetes patients

OBJECTIVE

This study assessed the relationship between the parameters of glycemic control, and zinc concentrations in blood and superoxide dismutase enzyme activity in type 2 diabetes patients.

SUBJECTS AND METHODS

Seventy-three individuals, aged between 25 and 59 years, were divided into the experimental group (type 2 diabetes patients, n = 36) and control group (n = 37). Plasma and erythrocyte zinc concentrations, superoxide dismutase activity, and parameters of glycemic control were analyzed.

RESULTS

Mean plasma zinc concentration was 74.1 ± 10.7 µg/dL and 68.8 ± 9.6 µg/dL, erythrocyte zinc concentration was 48.1 ± 9.5 µg/gHb and 41.2 ± 8.0 µg/gHb, and superoxide dismutase activity was 2248.9 ± 300.0 U/gHb and 2059.6 ± 285.4 U/gHb, in the experimental group and the control group, respectively (p < 0.05).

CONCLUSION

Type 2 diabetes patients showed a positive response to oxidative stress due to adequate zinc concentration in blood and increased activity of superoxide dismutase, and the enzyme was influenced by serum insulin.

Daily calcium intake and its relation to blood pressure, blood lipids, and oxidative stress biomarkers in hypertensive and normotensive subjects

Several studies revealed that low calcium intake is related to high prevalence of cardiovascular diseases such as hypertension. The prevalence of hypertension is high in Koreans along with their low dietary calcium consumption. Thus, the aim of this study was to evaluate the status of calcium intake between the hypertension and normotension groups and to investigate the correlation between dietary calcium intake and blood pressure, blood lipid parameters, and blood/urine oxidative stress indices. A total of 166 adult subjects participated in this study and were assigned to one of two study groups: a hypertension group (n = 83) who had 140 mmHg or higher in systolic blood pressure (SBP) or 90 mmHg or higher in diastolic blood pressure (DBP), and an age- and sex-matched normotension group (n = 83, 120 mmHg or less SBP and 80 mmHg or less DBP). The hypertension group consumed 360.5 mg calcium per day, which was lower than that of the normotension group (429.9 mg) but not showing significant difference. In the hypertension group, DBP had a significant negative correlation with plant calcium (P < 0.01) after adjusting for age, gender, body mass index (BMI), and energy intake. In the normotension group, total calcium and animal calcium intake were significantly and positively correlated with serum triglycerides. No significant relationship was found between calcium intake and blood/urine oxidative stress indices in both groups. Overall, these data suggest reconsideration of food sources for calcium consumption in management of the blood pressure or blood lipid profiles in both hypertensive and normotensive subjects.

Daily Manganese Intake Status and Its Relationship with Oxidative Stress Biomarkers under Different Body Mass Index Categories in Korean Adults

Manganese (Mn) is an essential micronutrient for human and plays an important role as a cofactor for several enzymes involving fatty acid synthesis, hepatic gluconeogenesis, and oxidative stresses. Also, Mn intake status has been reported to have beneficial effects in reversing metabolic dysfunction including obesity and nonalcoholic steatosis which is linked to mitochondrial dysfunction and oxidative stresses, however, information on dietary Mn intake in Koreans are limited. Hence we investigated the relationship between dietary Mn intake and antioxidant defense factors in healthy and obese subjects. Total of 333 healthy subjects were recruited in the study and were assigned to one of three study groups: a normal group (18.5-22.9), a overweight group (23-24.9), and a obesity group (>25) according to their body mass index (BMI). We assessed Mn intakes (24-hr recall method) and several indicators for antioxidative defenses such as glutathione (GSH), glutathione peroxidase (GPx) and urinary malonaldehyde (MDA). Results showed that body weight and blood pressure of study subjects were increased in dependent of their BMI (p < 0.01). However dietary Mn intakes and oxidative stress biomarkers (GSH, GPx, and MDA) were not significantly different by groups defined by BMI. In correlation analysis adjusting for age, sex and energy intake, dietary Mn intake of the subjects in different BMI categories were not significantly correlated with GSH, GPx, MDA and showed a weak or no association with these oxidative stress markers. In conclusion dietary Mn intake at least in this study has a little or no influence on markers of oxidative status in both healthy and obese subjects.

Evaluation of nitric oxide metabolites in a group of subjects with metabolic syndrome

AIM

To evaluate the concentration of metabolites (NO(2)(-), NO(3)(-)) of nitric oxide (NO) in metabolic syndrome (MS).

MATERIALS AND METHODS

We enrolled 106 subjects (45 women and 61 men) with MS of which 43 (14 women and 27 men) with diabetes mellitus and 63 (31 women and 32 men) without diabetes mellitus, and 54 subjects (19 women and 35 men) as control group. The nitric oxide metabolites (nitrite+nitrate=NOx) were evaluated employing the Griess reagent.

RESULTS

In the whole group of MS subjects was evident, in comparison with control group, a significant increase in NOx. The same finding was also present between control group and diabetic subjects with MS and between control group and nondiabetic subjects with MS. No difference was observed between the two subgroups (diabetic and nondiabetic subjects with MS) about NOx. Contrasting information were obtained examining the linear regression among NOx, age, anthropometric profile, blood pressure values and glycometabolic pattern of subjects with MS.

CONCLUSIONS

In MS subjects we found a significant increase in NOx not influenced by diabetes mellitus. The NOx is a parameter that must be considered in MS keeping in mind that its behavior is related to chronic inflammation that accompanies this clinical condition.

Evaluation of oxidative stress markers in pathogenesis of diabetic neuropathy

Experimental evidences suggest that hyperglycaemia-induced overproduction of reactive oxygen species and subsequent damage to proteins, lipids and DNA may play a key role in the development of distal symmetric polyneuropathy (DSPN)—the most common complication of diabetes mellitus. The study population consisted of 51 individuals aged 52–82 years classified into 3 groups: 16 patients diagnosed with type 2 diabetes mellitus (T2DM) with DSPN, 16 T2DM patients without DSPN and 19 control subjects without diabetes and neuropathy. The study was conducted to determine the activity of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and total antioxidant status (TAS) in the examined groups. An alkaline comet assay was used to determine the extent of DNA damage of oxidized purines as glicosylo-formamidoglicosylase (Fpg) sites, and oxidized pyrimidines as endonuclease III (Nth) sites. A significant decrease of SOD (P < 0.05), GPX (P < 0.05) and nonsignificant decrease of CAT (P > 0.05), and TAS status (P > 0.05) were seen in T2DM patients with neuropathy compared to T2DM patients as well as controls. T2DM patients with or without neuropathy revealed significantly lower (P < 0.05) plasma concentration of nitrous oxide compared to the control subjects. Endogenous level of oxidative DNA damage in T2DM patients with DSPN was significantly higher compared both to the controls and T2DM patients without DSPN (P < 0.001). Moreover, lymphocytes isolated from T2DM patients with DSPN were more susceptible to oxidative DNA lesions induced by hydrogen peroxide than from T2DM patients without DSPN (P < 0.001). Our results confirm hypothesis that oxidative stress may play a substantial role in the development and progression of diabetic distal symmetric polyneuropathy.

A comparative study on the in vitro antioxidant potentials of three edible fruits: cornelian cherry, Japanese persimmon and cherry laurel

This study was designed in order to investigate in vitro antioxidant potentials of 80% methanolic extracts prepared from three edible fruits, Cornus mas L., Diospyros kaki L., Laurocerasus officinalis Roem. For this purpose, 8 different tests were performed including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging tests, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), metal-chelating capacity, determination of total antioxidant capacity, β-carotene bleaching test in a linoleic acid emulsion system and trolox equivalent antioxidant capacity. In addition, for evaluating the phenolic profile, total phenolic, flavonoid and proanthocyanidin contents were measured spectrophotometrically. Among the three fruits analyzed, Diospyros kaki L. showed the highest activity in all tests, except β-carotene bleaching test. Whereas, neither of three fruits showed metal-chelating activity. Also, a good correlation was found between the phenolic content and antioxidant parameters.

Effect of potent ethyl acetate fraction of Stereospermum suaveolens extract in streptozotocin-induced diabetic rats

To evaluate the antihyperglycemic effect of ethyl acetate fraction of ethanol extract of Stereospermum suaveolens in streptozotocin-(STZ-) induced diabetic rats by acute and subacute models. In this paper, various fractions of ethanol extract of Stereospermum suaveolens were prepared and their effects on blood glucose levels in STZ-induced diabetic rats were studied after a single oral administration (200 mg/kg). Administration of the ethyl acetate fraction at 200 mg/kg once daily for 14 days to STZ-induced diabetic rats was also carried out. The parameters such as the fasting blood glucose, hepatic glycogen content, and pancreatic antioxidant levels were monitored. In the acute study, the ethyl acetate fraction is the most potent in reducing the fasting serum glucose levels of the STZ-induced diabetic rats. The 14-day repeated oral administration of the ethyl acetate fraction significantly reduced the fasting blood glucose and pancreatic TBARS level and significantly increased the liver glycogen, pancreatic superoxide dismutase, and catalase activities as well as reduced glutathione levels. The histopathological studies during the subacute treatment have been shown to ameliorate the STZ-induced histological damage of pancreas. This paper concludes that the ethyl acetate fraction from ethanol extract of Stereospermum suaveolens possesses potent antihyperglycemic and antioxidant properties, thereby substantiating the use of plant in the indigenous system of medicine.

Does diabetes mellitus-induced bladder remodeling affect lower urinary tract function? ICI-RS 2011

AIMS

Due to an increase in aging population and changing eating habits diabetes mellitus (DM) type II is a rapidly increasing condition worldwide. Although not so detrimental as other co-morbidities, uropathy contributes to a significantly reduced quality-of-life in those affected. The purpose of this ICS-RS report is to highlight clinical and basic research data to outline directions for further research and possible treatment approaches.

METHODS

This report is based on a think tank presentation and discussion at the ICI-RS 2011, original research data and literature research.

RESULTS

Clinical and experimental data confirm that detrusor overactivity, both neurogenic and myogenic, and changes in transmitter regulation leading to a hyper- excitability of the detrusor are the major findings in diabetic neuropathic bladders. These findings seem to be related to an earlier stage of DM, whereas detrusor underactivity appears to be linked to later stages of DM. Detrusor smooth muscle cells seem to be modulated directly by hyperglycemia. Data support the theory that hyperglycemia-induced oxidative stress in the detrusor smooth muscle and that micro- and macrovascular events are also responsible for urologic complications of DM.

CONCLUSIONS

DM causes bladder remodelling leading to uropathy in a mulitfactorial way. Future research should focus on the effects of DM as a function of time and develop novel animal models looking at defined aspects as well as interaction of different aspects- such as oxidative stress in neurogenic, myogenic and urothelial components and the role of inflammation and hypoxia caused by vascular complications.

Carnitine supplementation modulates high dietary copper-induced oxidative toxicity and reduced performance in laying hens

This experiment was conducted to evaluate the effects of L-carnitine on performance, egg quality and certain biochemical parameters in laying hens fed a diet containing high levels of copper proteinate. Forty-eight 42-week-old laying hens were divided into four groups with four replicates. The laying hens were fed with a basal diet (control) or the basal diet supplemented with either 400 mg carnitine (Car)/kg diet, 800 mg copper proteinate (CuP)/kg diet or 400 mg carnitine + 800 mg copper (Car+CuP)/kg diet, for 6 weeks. Supplemental CuP decreased feed consumption (p < 0.01), feed efficiency and egg production (p < 0.001), as compared to control. The combination of Car and CuP increased (p < 0.001) egg production and feed efficiency as compared to CuP. The activities of alanine aminotransferase (p < 0.05) and alkaline phosphatase (p < 0.01) were increased, while lactate dehydrogenase activity was decreased (p < 0.001) by supplemental CuP and Car+CuP. Supplemental CuP caused an increase in plasma malondialdehyde (p < 0.01) and nitric oxide levels (p < 0.05). In the Car+CuP group, this increase was observed to have been reduced significantly (p < 0.05). Furthermore, Car+CuP increased (p < 0.05) glucose level. These results indicate that the carnitine and copper combination may prevent the possible adverse effects of high dietary copper on performance and lipid peroxidation in hens.

Reduced nitrate level in individuals with hypertension and diabetes

BACKGROUND

Nitric oxide (NO) turnover is vital for proper endothelial function to maintain a healthy vascular system. Various risk factors responsible for hypertension and diabetes may disrupt this homeostasis, leading to decreased bioavailability and/or bioactivity of NO, which potentiates endothelial dysfunction. Plasma NO is a useful indicator of NO homeostasis and vascular endothelial function. Since endothelial function plays a key role in the development and progression of diseases like diabetes and hypertension, we sought to investigate the NO profile in patients having diabetes and hypertension and determine the relationship of NO turnover with the disease.

MATERIALS AND METHODS

For this purpose, three groups were studied for the NO production. The first group consisted of 74 hypertensive patients, the second group consisted of 72 diabetic patients and the third group consisted of 60 healthy controls. Nitrate synthase activity was evaluated by measuring nitrate level using an automated sample injector connected to an automated NO detector - Ion liquid chromatograph.

RESULTS

The plasma concentration of NO was found to be significantly lower in both essential hypertensive patients and diabetic patients without complications as compared to the healthy controls (P < 0.05).

CONCLUSION

This data confirms that different factors like hyperglycemia and blood pressure are seen to have immense influence on NO production.

Evaluation of antidiabetic potential of selected traditional Chinese medicines in STZ-induced diabetic mice

AIMS

Traditional Chinese medicine (TCM) has been used for treating complex chronic diseases owing to their fewer side-effects, better patient tolerance and relatively less cost. The present work was carried out to study the anti-diabetic efficacy and mechanisms of 34 TCMs.

MATERIALS AND METHODS

Streptozotocin (STZ)-diabetic mice were orally administrated with corresponding herbal solution once a day for 4 weeks. At the end of experiment, the level of plasma glucose, malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and the serum aldose reductase (AR) were determined, the effects of TCM extract on α-glucosidase and angiotensin-converting enzyme (ACE) in vitro were also evaluated.

RESULTS

13 out of the 34 herbs showed a statistically significant plasma glucose lowering action compared with the diabetic control group. Biochemical analysis revealed that Atractylodes macrocephala, Codonopsis pilosula, Dioscorea opposite, Flos lonicerae and Pueraria lobata may retard the progression of diabetes via reduce the blood glucose level and prevent the increase of AR activity. Other tested herbs, such as Ramulus cinnamomi, Cinnamomum cassia, and Eucommia ulmoides, showed the antidiabetic ability by either prevent the decrease in SOD activity or suppress the increase of MDA. Zymologic assay reveals that Pueraria lobata and Anemarrhena asphodeloides showed the highest inhibition against α-glucosidase and ACE respectively. Interestingly, the post-treatment glucose levels and AR activity were positively correlated with kidney/body weight of 34 herbs treated diabetic mice (p = 0.02, 0.04 respectively).

CONCLUSIONS

Several potential antidiabetic herbs derived from Chinese traditional pharmacopeia such as Dioscorea opposite, Pueraria lobata, Codonopsis pilosula and Ramulus cinnamomi, have been found to exert a beneficial action on diabetes and diabetic complications via multi-mechanisms.

Oxidative stress status and plasma trace elements in patients with asthma or allergic rhinitis

INTRODUCTION

This study was conducted to evaluate the oxidant/antioxidant balance (oxidative stress status) and plasma essential trace element levels in patients with bronchial asthma or allergic rhinitis.

METHODS

A total of 94 individuals consisting of 19 allergic asthmatics; 17 non-allergic asthmatics; 22 patients with allergic rhinitis; and 36 healthy control people were enrolled into this study. Superoxide dismutase (CuZnSOD) and glutathione peroxidase (GSH-Px) activity as antioxidant defence mechanism parameters, along with malondialdehyde (MDA) as a marker of lipid peroxidation, were determined in erythrocytes of patient groups and controls. Plasma copper and zinc levels were also determined in all groups.

RESULTS

CuZnSOD activity was significantly lower in all groups of patients (p<0.001 for allergic asthmatics, p=0.008 for allergic rhinitis patients, and p<0.001 for non-allergic asthmatics) when compared to those of controls. Erythrocyte GSH-Px enzyme activity was not different when compared to that of the control group. Similarly, the patient groups had no difference from those of the controls with respect to erythrocyte MDA levels. While plasma Cu levels in all asthmatic patients were not different from those of the controls, allergic rhinitis patients had significantly elevated (p<0.001) Cu levels compared to those of the controls. No statistically significant difference was established between patient groups and controls with respect to plasma zinc levels.

CONCLUSION

While defective CuZnSOD activity observed in all patients groups was expected to cause an increase in lipid peroxidation indicated by high MDA levels in these patients groups, the fact that MDA levels were not different from those of controls in all patient groups indicates that other components of anti-oxidant defence system preserve their functions in these patients. On the other hand, statistically significant difference between all patients groups and controls with respect to trace elements was only observed in allergic rhinitis patients who had higher levels of Cu than those of controls.

Hepatoprotective effect of ghrelin on carbon tetrachloride-induced acute liver injury in rats

BACKGROUND & AIMS

Recent studies have revealed that ghrelin may be an antioxidant and antiinflammatory agent. Oxidative stress are considered to play a prominent causative role in the development of various hepatic disorders. We investigated whether ghrelin plays a protective role against carbon tetrachloride (CCl(4))-induced acute liver injury in rats.

METHODS

Forty adult male Sprague-Dawley rats were randomly divided into four equal groups as; control, ghrelin, CCl(4) and ghrelin plus CCl(4). Evaluations were made for lipid peroxidation, enzyme activities and biochemical parameters. Pathological histology was also performed.

RESULTS

CCl(4) treatment increased plasma and liver tissue malondialdehyde (MDA) content and plasma nitric oxide (NO) level, and decreased erythrocyte and liver tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities when compared to control group. At the same time, CCl(4) treatment increased the serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alcaline phosphatase (ALP) activities. By contrast, ghrelin pretreatment reduced plasma and liver MDA content and plasma NO level, and increased erythrocyte and liver tissue SOD, CAT and GPx activities when compared with CCl(4)-treated group. Moreover, both ghrelin alone and ghrelin plus CCl(4) treatment elevated serum glucose level. The CCl(4)-induced histopathological changes were also reduced by the ghrelin pretreatment.

CONCLUSION

Our results show that ghrelin can be proposed to protect the liver against CCl(4)-induced oxidative damage in rats, and the hepatoprotective effect may be correlated with its antioxidant and free radical scavenger effects.

Identification of trans-tiliroside as active principle with anti-hyperglycemic, anti-hyperlipidemic and antioxidant effects from Potentilla chinesis

AIM OF THE STUDY

The present study was carried out to isolate and identify trans-tiliroside as principal compound with anti-hyperglycemic, anti-hyperlipidemic and antioxidant effects from Potentilla chinesis.

MATERIALS AND METHODS

A bioactive compound, trans-tiliroside was isolated from the ethanol extract of Potentilla chinesis and its administration dose was optimized and patented. The normal, alloxan-induced diabetic mice and streptozotocin-induced diabetic rats were used to evaluate the anti-hyperglycemic, anti-hyperlipidemic and antioxidant effects of trans-tiliroside from Potentilla chinesis. Biochemical parameters were assayed in blood samples of different groups of alloxan-induced diabetic mice and streptozotocin-induced diabetic rats.

RESULTS

The level of fasting serum glucose levels, triglycerides (TG) and total cholesterol (TC) in alloxan-induced diabetic mice were significantly decrease after daily oral administration of trans-tiliroside in normal and diabetic mice at doses of 0.4, 0.8 and 1.6 mg/kg/day, for 15 days. Blood glucose level was significant decrease in STZ induced diabetic rats by trans-tiliroside (1.2 and 0.3mg/kg body weight for 10 weeks). The content of TC, low density lipoprotein (LDL-C) and TG levels were decreased and high density lipoprotein (HDL-C) content was increased, so lipid metabolism was improved. Moreover, trans-tiliroside revealed antioxidant activity as shown by increased activities of superoxide dismutase (SOD), decreased level of malondialdehyde (MDA) in diabetic rats. Histological morphology examination showed that the trans-tiliroside restored the damage of pancreas tissues in rats with diabetes mellitus.

CONCLUSION

Trans-tiliroside, a constituent from Potentilla chinesis, revealed significant anti-hyperglycemic, anti-hyperlipidemic and antioxidant activities.

Oxidative stress status in patients with chronic idiopathic urticaria

AIM

The controversial data related to oxidative stress status in patients with chronic idiopathic urticaria (CIU) have been reported. Therefore, the present study was aimed to contribute to this debate by determining oxidative stress markers along with some trace element levels in patients with CIU.

METHODS

Twenty-five patients with CIU (10 males, 15 females) and 36 healthy controls were enrolled into the study. Erythrocyte lipid peroxidation status, scavenger enzyme activities and trace element levels were determined.

RESULTS

While erythrocyte MDA levels, erythrocyte GSH- Px activities and erythrocyte Zn levels showed no differences between the patient and control groups, a statistically significant decrease and increase were observed in erythrocyte CuZn-SOD activities and Cu levels, respectively, in the CIU patients when compared to those of the controls (p < 0.001 for both of them).

CONCLUSION

In conclusion, an oxidative burden which can be relieved by some preserved antioxidant mechanisms seems to be present in patients with CIU even if they are clinically stable and it may probably have a role in the pathogenesis.

Advances in metal-induced oxidative stress and human disease

Detailed studies in the past two decades have shown that redox active metals like iron (Fe), copper (Cu), chromium (Cr), cobalt (Co) and other metals undergo redox cycling reactions and possess the ability to produce reactive radicals such as superoxide anion radical and nitric oxide in biological systems. Disruption of metal ion homeostasis may lead to oxidative stress, a state where increased formation of reactive oxygen species (ROS) overwhelms body antioxidant protection and subsequently induces DNA damage, lipid peroxidation, protein modification and other effects, all symptomatic for numerous diseases, involving cancer, cardiovascular disease, diabetes, atherosclerosis, neurological disorders (Alzheimer's disease, Parkinson's disease), chronic inflammation and others. The underlying mechanism of action for all these metals involves formation of the superoxide radical, hydroxyl radical (mainly via Fenton reaction) and other ROS, finally producing mutagenic and carcinogenic malondialdehyde (MDA), 4-hydroxynonenal (HNE) and other exocyclic DNA adducts. On the other hand, the redox inactive metals, such as cadmium (Cd), arsenic (As) and lead (Pb) show their toxic effects via bonding to sulphydryl groups of proteins and depletion of glutathione. Interestingly, for arsenic an alternative mechanism of action based on the formation of hydrogen peroxide under physiological conditions has been proposed. A special position among metals is occupied by the redox inert metal zinc (Zn). Zn is an essential component of numerous proteins involved in the defense against oxidative stress. It has been shown, that depletion of Zn may enhance DNA damage via impairments of DNA repair mechanisms. In addition, Zn has an impact on the immune system and possesses neuroprotective properties. The mechanism of metal-induced formation of free radicals is tightly influenced by the action of cellular antioxidants. Many low-molecular weight antioxidants (ascorbic acid (vitamin C), alpha-tocopherol (vitamin E), glutathione (GSH), carotenoids, flavonoids, and other antioxidants) are capable of chelating metal ions reducing thus their catalytic activity to form ROS. A novel therapeutic approach to suppress oxidative stress is based on the development of dual function antioxidants comprising not only chelating, but also scavenging components. Parodoxically, two major antioxidant enzymes, superoxide dismutase (SOD) and catalase contain as an integral part of their active sites metal ions to battle against toxic effects of metal-induced free radicals. The aim of this review is to provide an overview of redox and non-redox metal-induced formation of free radicals and the role of oxidative stress in toxic action of metals.

Pathological aspects of lipid peroxidation

Lipid peroxidation (LPO) product accumulation in human tissues is a major cause of tissular and cellular dysfunction that plays a major role in ageing and most age-related and oxidative stress-related diseases. The current evidence for the implication of LPO in pathological processes is discussed in this review. New data and literature review are provided evaluating the role of LPO in the pathophysiology of ageing and classically oxidative stress-linked diseases, such as neurodegenerative diseases, diabetes and atherosclerosis (the main cause of cardiovascular complications). Striking evidences implicating LPO in foetal vascular dysfunction occurring in pre-eclampsia, in renal and liver diseases, as well as their role as cause and consequence to cancer development are addressed.

The effect of sevoflurane and desflurane on markers of oxidative status in erythrocyte

The aim of our study was to evaluate the markers of oxidative status of erythrocyte during general anesthesia and compare the markers of oxidative status of erythrocyte in both sevoflurane and desflurane. Venous blood samples of patients were collected the following time intervals; initial time (IT) and first hour (1st h), first (1st day) and third days (3rd day) after anesthesia (sevoflurane and Desflurane). The levels of magnesium (Mg), zinc (Zn) as a cofactor of these enzymes, malondialdehyde (MDA) and the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzymes were also determined. No significant changes were observed in these measurements when the patients were exposed to desflurane anesthesia. On the other hand, the levels of Zn on erythrocytes were significantly increased at 1st hour and 1st and 3rd days compared to initial time in sevoflurane group (p < 0.01, p < 0.01, and p < 0.05, respectively). The activity of GSH-Px was significantly increased (p = 0.05) while the activity of SOD was significantly decreased (p < 0.01) at 1st hour after administration of sevoflurane compared to the initial time. There were no changes on the levels of Mg and MDA. Our results showed that sevoflurane has more impacts on the antioxidant status of erythrocytes than desflurane.

No altered blood pressure and serum markers of oxidative stress after a long time dietary fish oil in the genetically 9 month-old type-2 diabetes Zucker rat

In this study, we investigated the effect of a high n-3 fatty acid diet (eicosapentaenoic and docosahexaenoic acids) in Zucker obese and lean rats on blood pressure in association with physiological parameters, serum biochemistry and oxidative stress analysis. After 150 days of treatment, dietary fish oil supplementation in Zucker obese rats (9 months of age) reduces bodyweight gain and serum triglyceridemia and nitrite levels, increases serum glucose and angiotensin converting enzyme activity, but does not alter blood pressure, cholesterol levels and serum markers of oxidative stress (malondialdehyde, glutathione), compared to the Zucker rats fed control diet. According to these results, we can consider that after 150 days of treatment, fish oil is not enough to regulate parameters involved in the metabolic syndrome, such as cholesterolemia and blood pressure, in a 9 month-old genetically type-2 diabetes rat.

Emerging gene and stem cell therapies for the treatment of erectile dysfunction

Erectile dysfunction is a prevalent condition that leads to significant morbidity and distress, not just for affected men but also for their partners. Very few currently available treatments ameliorate the underlying causes of the disorder and 'cure' the disease state. Much recent effort has been focused on the development of gene and cell-based approaches to rectify the molecular and tissue defects responsible for ED. Gene therapy has been investigated in animal models as a means to restore normal function to the penis; at this time, however, only one human trial has been published in the peer-reviewed literature. Recent gene therapy studies have focused on the modulation of enzymes associated with the NOS/cGMP pathway, and supplementation of trophic factors, peptides and potassium channels. Stem cell therapy has been a topic of interest in more recent years but there are currently very few published reports in animal models and none in human men. Although stem cell therapy offers the potential for restoration of functional tissues, legitimate concerns remain regarding the long-term fate of stem cells. The long-term safety of both gene and stem cell therapy must be thoroughly investigated before large-scale human studies can be considered.

Effect of pan-retinal laser photocoagulation on plasma VEGF, endothelin-1 and nitric oxide in PDR

AIM

To study plasma levels of vascular endothelial growth factor (VEGF), endothelin-1(ET-1) and nitric oxide (NO) in patients with proliferative diabetic retinopathy (PDR) before and after pan-retinal photocoagulation (PRP).

METHODS

Forty patients (23 females and 17 males, mean age 48.5±12.2 years) with PDR without previous PRP therapy were studied. Blood samples were obtained before and 3 months after the last PRP session. Baseline (prelaser) plasma levels of VEGF, ET-1 and NO were compared with their levels in 30 healthy age- and sex- matched controls and also with plasma levels 3 months post-PRP.

RESULTS

Patients with PDR had significantly raised plasma VEGF (375±89ng/L), ET-1(20±5ng/L) and NO (135±53µmol/L) when compared with healthy control group (P<0.01). After PRP, there was a significant reduction in plasma VEGF (179±66ng/L), ET-1 (11±5ng/L) and NO (91±49µmol/L) levels at 3 months' follow-up but still significantly higher than healthy controls.

CONCLUSION

Patients with PDR demonstrate elevated VEGF, ET-1 and NO, which decrease after successful laser treatment.

Effects of repeated seafood consumption on urinary excretion of arsenic species by volunteers

Arsenic (As) is a known human carcinogen and widely distributed in the environment. The main route of As exposure in the general population is through food and drinking water. Seafood harvested in Korea contains high-level organoarsenics such as arsenobetaine, arsenocholine, and arsenosugars, which are much less harmful than inorganic arsenics. However, for those who eat large amounts of seafood it is important to understand whether seafood consumption affects urinary levels of inorganic As metabolites such as arsenite, arsenate, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA). In this study we investigated urinary As metabolites (inorganic As, MMA[V], DMA[V]) and some biological indexes such as AST, GSH, GPX, lipid peroxidation, and uric acid in volunteer study subjects (seven males and nine females). Total urinary As metabolites were analyzed by the hydride generation method, followed by arsenic speciation using HPLC with ICP-mass spectrometry. Study subjects refrained from eating seafood for 3 days prior to the first urine collection and then ingested seafood daily for 6 consecutive days. The first voided urine of the morning was collected from each subject the first day of the consecutive 6 days of seafood ingestion but prior to the first seafood meal. The first voided urine of the morning was also collected on days 1, 2, 3, 4, 5, 6, 7, 10, and 14 after seafood ingestion. The daily mean intake of total As was 6.98 mg, comprised of 4.71 mg of seaweed (67%), 1.74 mg of flat fish (25%), and 0.53 mg of conch (8%). We observed a substantial increase in total urinary As metabolites for subjects consuming seafood from day 1, which recovered to control level at day 10. The increase in total urinary As metabolites was attributed to the increase in DMA, which is a more harmful metabolite than organoarsenics. However, no significant changes in response biological indexes were observed. These results suggest that it is necessary to evaluate As metabolism when assessing the exposure to inorganic As and potential chronic health effects of seafood consumption in Korea.

Modulation of nitrosative/oxidative stress in the lung of hyperglycemic rabbits by two antidiabetics, pioglitazone and repaglinide

The lungs are involved in diabetes in the cause of the complex phenomena diabetes generates. In the present study, hyperglycemia inhibited pulmonary antioxidants, including superoxide dismutase, catalase, glutathione peroxidase, and glutathione. These effects were accompanied by significant elevation of lipid peroxidation, total nitrites, and nitrotyrosine levels. The study investigated the effects of 2 oral antidiabetics, pioglitazone and repaglinide, on the mentioned parameters. It is concluded that pioglitazone exerts protective effect in the lung by inhibiting nitrosative stress and normalizing the nitrites and nitrotyrosine levels. Administration of repaglinide prevents oxidative and, to a smaller extent, nitrosative changes.

Effects of N-acetylcysteine, deferoxamine and selenium on doxorubicin-induced hepatotoxicity

The aims of our study were to evaluate the antioxidant defence mechanisms of liver tissue challenged by doxorubucin (DOX) and to compare the possible protective effects of N-acetylcysteine (NAC) (n=10), deferoxamine (DOF) (n=10), DOF+NAC (n= 10) and selenium (n=9) on doxorubicin-induced hepatotoxicity. Fifty-six male rats (Mean weight = 250 ± 50 g) randomly divided into five groups. Animals in study groups were pretreated with a single dose of Dox, which was administered intravenously. Control group (n=7) was treated with intravenous saline injection. Selenium was given intraperitoneally. Blood and urine samples were collected before sacrifice. Liver tissue samples were collected and tissue superoxide dismutase (SOD), glutathione peroxidase (GSH-px), CAT activity, MDA, Zn, iron and copper were determined. DFO decreased lipid peroxidation significantly. DFO and NAC decreased CAT activity significantly. Antioxidant regimes increase SOD activities significantly. DOF and NAC increase GSH-px activities and copper levels significantly. Beneficial effect of selenium seems to result from its stimulation of SOD but not to GSH-px. It has been found that DOF, NAC and selenium have protective effects on Dox-induced hepatocellular damage. DOF+NAC did not result additional benefit.

Zinc and diabetes--clinical links and molecular mechanisms

Zinc is an essential trace element crucial for the function of more than 300 enzymes and it is important for cellular processes like cell division and apoptosis. Hence, the concentration of zinc in the human body is tightly regulated and disturbances of zinc homeostasis have been associated with several diseases including diabetes mellitus, a disease characterized by high blood glucose concentrations as a consequence of decreased secretion or action of insulin. Zinc supplementation of animals and humans has been shown to ameliorate glycemic control in type 1 and 2 diabetes, the two major forms of diabetes mellitus, but the underlying molecular mechanisms have only slowly been elucidated. Zinc seems to exert insulin-like effects by supporting the signal transduction of insulin and by reducing the production of cytokines, which lead to beta-cell death during the inflammatory process in the pancreas in the course of the disease. Furthermore, zinc might play a role in the development of diabetes, since genetic polymorphisms in the gene of zinc transporter 8 and in metallothionein (MT)-encoding genes could be demonstrated to be associated with type 2 diabetes mellitus. The fact that antibodies against this zinc transporter have been detected in type 1 diabetic patients offers new diagnostic possibilities. This article reviews the influence of zinc on the diabetic state including the molecular mechanisms, the role of the zinc transporter 8 and MT for diabetes development and the resulting diagnostic and therapeutic options.