Antioxidant Status in the Blood of Patients With Active Vitiligo

We have previously reported that patients with active vitiligo (AVP) have elevated urinary levels of catecholamine metabolites, such as homovanillic and vanilmandelic acids, irrespective of the form of the disease (acrofacial, segmental, generalized). We have suggested that abnormal release of catecholamines from autonomic nerve endings might play an etiological role in the onset and development of vitiligo through an overproduction of toxic (oxy)radicals in the microenvironment of melanocytes in the affected areas. In the present study we have investigated whether this suggested increase in radicals might be associated with an oxidative stress in the blood of AVP. We have analyzed by gas-chromatography mass-spectrometry, by high pressure liquid chromatography, by spectophotometry plasma levels of vitamin E (Vit E), lipoperoxides (LIP), and polyunsaturated fatty acids of phospholipids (PL-FA), erythrocyte reduced glutathione (GSH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in 62 patients affected with different forms of active vitiligo (acrofacial, segmental, generalized) and in 60 age-matched controls. Our results show that blood levels of Vit E, SOD, GSH, GSH-Px activity, LIP and PL-FA in AVP were not significantly different from those of healthy age matched controls, indicating that melanocyte damage in vitiligo is not linked with a generalized oxidative stress.     

Blood antioxidant status and urinary levels of catecholamine metabolites in beta-thalassemia.

It has been reported that iron overload in beta-thalassemia leads to an enhanced generation of reactive oxygen species and to oxidative stress. We have studied the oxidant/antioxidant imbalance in the blood of 48 transfusion-dependent beta-thalassemic patients (TLP) (17 males, 31 females, 11-22 year), under chelation therapy, and in 40 sex and age matched healthy controls (CTR). Plasma and lymphocyte levels of vitamin E (Vit E), ubiquinol (CoQ10H2), ubiquinone (CoQ10), plasma concentrations of vitamin A (Vit A), beta-carotene, lycopene, vitamin C (Vit C), total thiols, fatty acid patterns of phospholipids (PL-FA), and plasma and urinary markers of lipoperoxidation (TBA-RM, conjugated dienes, and azelaic acid (AZA), as well as the urinary levels of catecholamine and serotonin metabolites, were evaluated by gas chromatography-mass spectrometry (GC-MS), HPLC and spectrophotometry. Routine laboratory blood analyses were performed on the same samples; 39/48 TLP were HCV positive. Blood samples were collected just before transfusion, the 24 h urine samples the day before. Our results clearly showed that a severe oxidative stress occurs in the plasma of TLP in comparison with CTR. In fact, the levels of lipophilic antioxidants and ascorbate were severely depleted: CoQ10H2 (-62.5%), total CoQ10 (-35.1%), Vit E (-43.8%), beta-carotene (-31.1%), lycopene (-63.7%), Vit A (-35.9%), Vit C (-23.1%). The impairment of the antioxidant status was associated with elevated plasma levels of by-products of lipoperoxidation and urinary concentrations of catecholamine metabolites and of AZA, indicating a high degree of both neurological stress and lipoperoxidation. A significant positive correlation was found between vitamin E and non-transferrin-bound iron (NTBI) (r = -0.81; p < 0.001), while no correlation was found between antioxidant depletion and ferritin serum levels, average blood consumption, or the presence of clinical complications. The administration of selective antioxidants along with an appropriate diet might represent a promising way of counteracting oxidative damage and its deleterious effects on the progression of the disease.     

Blood antioxidant status and urinary levels of catecholamine metabolites in β-thalassemia

It has been reported that iron overload in β-thalassemia leads to an enhanced generation of reactive oxygen species and to oxidative stress. We have studied the oxidant/antioxidant imbalance in the blood of 48 transfusion-dependent β-thalassemic patients (TLP) (17 males, 31 females, 11–22 year), under chelation therapy, and in 40 sex and age matched healthy controls (CTR). Plasma and lymphocyte levels of vitamin E (Vit E), ubiquinol (CoQ₁₀H₂), ubiquinone (CoQ₁₀), plasma concentrations of vitamin A (Vit A), β-carotene, lycopene, vitamin C (Vit C), total thiols, fatty acid patterns of phospholipids (PL-FA), and plasma and urinary markers of lipoperoxidation (TBA-RM, conjugated dienes, and azelaic acid (AZA), as well as the urinary levels of catecholamine and serotonin metabolites, were evaluated by gas chromatography-mass spectrometry (GC-MS), HPLC and spectrophotometry. Routine laboratory blood analyses were performed on the same samples; 39/48 TLP were HCV positive. Blood samples were collected just before transfusion, the 24 h urine samples the day before. Our results clearly showed that a severe oxidative stress occurs in the plasma of TLP in comparison with CTR. In fact, the levels of lipophilic antioxidants and ascorbate were severely depleted: CoQ₁₀H₂ (-62.5%), total CoQ₁₀ (-35.1%), Vit E (-43.8%, β-carotene (-31.1%), lycopene (-63.7%), Vit A (-35.9%), Vit C (-23.1%). The impairment of the antioxidant status was associated with elevated plasma levels of by-products of lipoperoxidation and urinary concentrations of catecholamine metabolites and of AZA, indicating a high degree of both neurological stress and lipoperoxidation. A significant positive correlation was found between vitamin E and non-transferrin-bound iron (NTBI) (r = -0.81; p < 0.001), while no correlation was found between antioxidant depletion and ferritin serum levels, average blood consumption, or the presence of clinical complications. The administration of selective antioxidants along with an appropriate diet might represent a promising way of counteracting oxidative damage and its deleterious effects on the progression of the disease.     

Epidermal Oxidative Stress in Vitiligo

Epidermal levels of enzymatic and non-enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), vitamin E (Vit E), ubiquinol (CoQ₁₀H₂), and reduced glutathione (GSH), as well as polyunsaturated fatty acids of phospholipids (PL-PUFA), were evaluated in the affected epidermis of 15 patients with active vitiligo (AVP) and in the corresponding epidermis of 15 healthy phototype matched controls. The epidermal levels of CoQ₁₀H₂, Vit E, GSH, and CAT activity were significantly reduced in AVP and were associated with a marked increase of oxidized glutathione, whereas SODs and GSH-Px activities and ubiquinone concentration remained similar to control values. Antioxidant deficiency, in particular the decline of lipophilic antioxidants, i. e., CoQ₁₀H₂ and Vit E, accounts well for PL-PUFA reduction observed in vitiligo epidermis, mainly affecting C18: 3 n-3, C20: 3 n-6, C20: 4 n-6, and C22: 6 n-3 fatty acids and suggesting the occurrence of a lipoperoxidative process. In conclusion, both an imbalance of the intracellular redox status and a significant depletion of enzymatic and non-enzymatic antioxidants feature the epidermis of AVP, and represent a fingerprint of an abnormal oxidative stress leading to epidermal cell injury.     

The effects of hydrogen peroxide promoted by homocysteine and inherited catalase deficiency on human hypocatalasemic patients

Elevated plasma homocysteine can generate oxygen free radicals and hydrogen peroxide. The enzyme catalase is involved in the protection against hydrogen peroxide. We examined the effect of oxidative stress promoted by homocysteine on erythrocyte metabolism (blood hemoglobin, MCV, folate, B12, serum LDH, LDH isoenzymes, haptoglobin) in the oxidative stress sensitive Hungarian patients with inherited catalase deficiency. The plasma homocysteine (HPLC method, Bio-Rad), folate, B12 (capture binding assay, Abbott), blood hemoglobin concentrations, blood catalase activity (spectrophotometric assay of hydrogen peroxide), and MCV values were determined in 7 hypocatalasemic families including hypocatalasemic (male:12, female:18) patients and their results were compared to those of the normocatalasemic (male:17 female: 12) family members. We found decreased (p <.036) folate (ng/ml) concentrations (male hypocatalasemic 5.44 +/- 2.81 vs. normocatalasemic 7.56 +/- 1.97, female 5.01 +/- 1.93 vs. 6.61 +/- 1.91), blood hemoglobin (p <.010, male:140.2 +/- 11.0 vs. 153.6 +/- 11.6 g/l, female: 128.4 +/- 10.9 vs. 139.6 +/- 9.2 g/l). Increased levels of MCV (p <.001) were detected in hypocatalasemic patients (male: 98.6 +/- 3.4 vs. 90.1 +/- 7.5 fl, female: 95.9 +/- 3.9 vs. 90.1 +/- 2.5 fl), plasma homocysteine (p <.049, male: 9.72 +/- 3.61 vs. 7.36 +/- 2.10 umol/l, female: 9.06 +/- 3.10 vs. 6.84 +/- 2.50 umol/l) and not significant (p >.401) plasma B12 (male: 336 +/- 108 vs. 307 +/- 76 pg/ml, female: 373 +/- 180 vs. 342 +/- 75 pg/ml). The serum markers of hemolysis (LDH, LDH isoenzymes, haptoglobin) did not show significant (p >.228) signs of oxidative erythrocyte damage. We report firstly on increased plasma homocysteine concentrations in inherited catalase deficiency. The increased plasma homocysteine and inherited catalase deficiency together could promote oxidative stress via hydrogen peroxide. The patients with inherited catalase deficiency are more sensitive to oxidative stress of hydrogen peroxide than the normocatalasemic family members. This oxidative stress might be responsible for the decreased concentration of the blood hemoglobin via the oxidation sensitive folate and may contribute to the early development of arteriosclerosis and diabetes in these patients.     

Oxidative protein damage in plasma of type 2 diabetic patients.

In this study, we evaluated protein oxidation in 84 patients with Type 2 diabetes with no complications and in 61 healthy volunteers who formed the control group, whose ages matched those of the patients. We determined plasma carbonyl and plasma thiol levels as markers of oxidative protein damage and erythrocyte glutathione, plasma ceruloplasmin and transferrin as markers of free radical scavengers. The concentrations (mean +/- SD) of both of plasma carbonyl (1.24 +/- 0.46 vs. 0.72 +/- 0.17 nmole/mg protein; p < 0.0001) and lipid hydroperoxides (1.8 +/- 0.63 vs. 1.3 +/- 0.21 micromole/l; p < 0.0001) were increased, and the concentration of plasma transferrin (3.85 +/- 0.65 vs. 4.59 +/- 0.79 g/l; p < 0.05) was decreased, respectively, in Type 2 diabetic patients compared with those of the controls. There were no significant differences in the concentrations of plasma thiol (0.0064 +/- 0.001 vs. 0.0068 +/- 0.001 micromole/mg protein), erythrocyte glutathione (2.54 +/- 0.57 vs. 2.65 +/- 0.56 mg/g Hb), plasma ceruloplasmin (548 +/- 107.30 vs. 609 +/- 93.34 mg/l) between the patients and the controls. These changes observed in diabetic patients contribute to the imbalance in the redox status of the plasma. We attribute this imbalance to oxidative protein damage in Type 2 diabetic patients clinically free of complications.     

The effects of isosorbide dinitrate on methemoglobin reductase enzyme activity and antioxidant states

Isosorbide dinitrate (ISDN) has been used in the treatment of ischaemic cardiovascular diseases for many years. ISDN is the most popular nitric oxide donor and causes methemoglobinemia as an important side-effect. The purpose of this study was to examine antioxidant states and methemoglobin reductase activity after giving ISDN and ISDN plus vitamin E. Rats were divided into three groups according to the treatment: control group, ISDN group and ISDN plus vit. E group. We measured reduced glutathione in blood (GSH), plasma malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and NADH-dependent methemoglobin reductase activities. In the ISDN group, plasma MDA levels were significantly high compared to the control and ISDN + vit. E groups (p < 0.001). In the ISDN and ISDN + vit. E groups, blood GSH levels were higher than those of the control group (p < 0.05). Changes of SOD and GPx activities were not significant. In the ISDN and ISDN + vit. E groups the erythrocyte catalase and NADH-dependent methemoglobin reductase activities were significantly higher than that in the control group (p < 0.001). We conclude that oxidant drugs such as ISDN need to be carefully used because of lipid peroxidation and methemoglobinemia. These findings support the notion that vitamine E protects tissues against oxidative stress.     

Combined (n-3 and n-6) essential fatty deficiency is a potent modulator of plasma lipids, lipoprotein composition, and lipolytic enzymes

Essential fatty acids (EFA) are important structural and functional components of cell membranes. Their deficiency has been associated with several clinical and biochemical abnormalities. In the present study, the lipid profile as well as the concentration, composition, and metabolism of lipoproteins were examined in rats rendered EFA-deficient over a period of 12 weeks. Changes in plasma fatty acids mainly induced an increase of palmitoleic (16:1 n-7) and eicosatrienoic (20:3 n-9) acids, while linoleic (18:2 n-6), arachidonic (20:4 n-6), linolenic (18:3 n-3), and docosahexaenoic (22:6 n-3) acids were decreased. The results show increased concentrations of free fatty acids (FFA) (P less than 0.001), triglycerides (P less than 0.001), total cholesterol (P less than 0.02), free cholesterol (P less than 0.005), and phospholipids (P less than 0.05) when compared to pair-fed controls. Similar levels of cholesteryl esters were found in the two groups, and lecithin: cholesterol acyltransferase activity (nmol/100 microliters plasma per h) (8.98 +/- 1.44 vs 8.72 +/- 0.50) did not differ. On the other hand, postheparin extrahepatic lipoprotein lipase (LPL) activity was significantly (P less than 0.002) decreased (5.96 +/- 0.29 vs 7.29 +/- 0.68 mumol FFA/ml per h) and could account for the hypertriglyceridemia as well for the relative triglyceride enrichment of very low density lipoprotein, intermediate density lipoprotein, and low density lipoprotein particles. This enzymatic depletion of LPL was mainly due to the adipose tissue, since a higher level (P less than 0.001) of hepatic lipase (325.8 +/- 16.0 vs 130.8 +/- 9.5 nmol FFA/mg protein per h) was found in liver acetone powder extracts.(ABSTRACT TRUNCATED AT 250 WORDS)     

Methionine challenge paradoxically induces a greater activation of the antioxidant defence in subjects with hyper- vs. normohomocysteinemia

To determine whether hyperhomocysteinemia induced post-methionine loading (PML) is associated with different response in the aminothiol redox state and oxidative stress vs. normohomocysteinemia, we assessed PML plasma thiols, vitamins, free malondialdehyde (MDA), and blood reduced glutathione (GSH) in 120 consecutive subjects (50 [35-56] years, 83 males), divided into two groups according to PML plasma total Hcy < 35 microM (Group 1, n = 65) or > or = 35 microM (Group 2, n = 55).In the group as a whole, plasma reduced cysteine and cysteinylglycine, blood reduced GSH (all p for time = 0.0001) and plasma total GSH (p for time = 0.001) increased from baseline to PML. MDA values were unchanged. Group 1 and 2 differed in blood reduced GSH (p for group = 0.004, higher in Group 2), and MDA levels (p for group = 0.024, lower in Group 2).The oxidative stress induced by methionine challenge seems to be opposed by scavenger molecules activation, namely GSH, and lipid peroxidation does not increase. This mechanism paradoxically appears to be more efficient in hyperhomocysteinemic subjects.     

The effect of vitamin E and plant extract mixture composed of carvacrol, cinnamaldehyde and capsaicin on oxidative stress induced by high PUFA load in young pigs

The objective of our study was to determine the antioxidative potential of a plant extract (PE) mixture composed of carvacrol, capsicum oleoresin and cinnamaldehyde against high n-3 polyunsaturated fatty acid (PUFA)-induced oxidative stress in young pigs. Thirty-two weaned castrated male crossbred pigs (BW 10.9 kg; n = 32) were randomly assigned to four dietary treatments (n = 8). The negative control diet (Cont) contained 17.2% energy from fat. Oxidative stress was induced in three of the four experimental groups with the inclusion of n-3 PUFA rich linseed oil. Linseed oil substituted wheat starch in the diet to elevate the amount of energy from fat to 34.1%. One of these diets served as a positive control (Oil), one was additionally supplemented with 271.2 mg/kg of PE mixture and one with 90.4 mg/kg α-tocopheryl acetate (Vit E). After 14 days of treatment, blood and urine were collected for the determination of lipid peroxidation and DNA damage. Lipid peroxidation was studied by plasma malondialdehyde (MDA) concentrations, 24 h urinary MDA and F2-isoprostane (iPF2α-VI) excretion, total antioxidant status of plasma and glutathione peroxidase assays. Lymphocyte DNA fragmentation and 24 h urinary 8-hydroxy-2'-deoxyguanosine excretion were measured to determine DNA damage. Consumption of n-3 PUFA rich linseed oil increased the amount of MDA in plasma and urine, and induced DNA damage in lymphocytes, but did not elevate the amount of iPF2α-VI excreted in the urine. The supplementation with PE and with Vit E did not reduce MDA levels in plasma and urine, but it decreased the percentage of DNA damage in lymphocytes (P < 0.001). The PE reduced the urinary iPF2α-VI excretion in comparison to the Cont diet. The results show that PE and Vit E supplemented to pigs in concentrations of 271.2 mg/kg and 90.4 mg/kg, respectively, can effectively protect pig's blood lymphocytes against oxidative DNA damage, thus suggesting their potentially beneficial effects on the immune system under dietary-induced oxidative stress.     

Plasma and atrial levels of atrial natriuretic peptide (ANP) in pulmonary hypertensive rats

Immunoreactive atrial natriuretic peptide (IR-ANP) was measured in plasma and atrium of normal and monocrotaline induced pulmonary hypertensive rats (PH rats). In these animals, there was right ventricular hypertrophy and right ventricular systolic pressure was elevated. Fourteen days after a single dose of monocrotaline (40 mg/kg), plasma IR-ANP concentrations were significantly elevated (964.3 +/- 63.0 pg/ml vs. 521.0 +/- 81.9 pg/ml in controls, p less than 0.001). Tissue levels of IR-ANP in the right atrium in PH rats was significantly lower than those in the controls (45.1 +/- 3.9 ng/mg vs. 240.5 +/- 10.4 ng/mg, p less than 0.001), while there was no significant difference in tissue levels of atrial IR-ANP in the left atrium between the two groups. Thus, development of pulmonary hypertension led to an increase in release of ANP from the right atrium.     

Exercise-induced endotoxemia: the effect of ascorbic acid supplementation

Strenuous, long-duration aerobic exercise results in endotoxemia due to increased plasma levels of lipopolysaccharide (LPS) leading to cytokine release, oxidative stress, and altered gastrointestinal function. However, the effect of short-term strenuous aerobic exercise either with or without antioxidant supplementation on exercise-induced endotoxemia is unknown. A significant increase in the concentration of bacterial LPS (endotoxin) was noted in the venous circulation of healthy volunteers following maximal acute aerobic exercise (0.14(-1) pre-exercise vs. 0.24(-1) postexercise, p <0.01). Plasma nitrite concentration also increased with exercise (0.09 +/- 0.05 nM x ml(-1) vs. 0.14 +/- 0.01 nM x ml(-1), p <0.05) as did ascorbate free radical levels (0.02 +/- 0.001 vs. 0.03 +/- 0.002 arbitrary units, p <0.05). Oral ascorbic acid supplementation (1000 mg) significantly increased plasma ascorbic acid concentration (29.45 mM x l(-1) to 121.22 mM x l(-1), p <0.05), and was associated with a decrease in plasma LPS and nitrite concentration before and after exercise (LPS: 0.01(-1); nitrite: 0.02 +/- 0.02 nM x ml(-1) vs. 0.02 +/- 0.03 nM x ml(-1)). Ascorbic acid supplementation led to a significant increase in ascorbate free radical levels both before (0.04 +/- 0.01 arbitrary units) and after exercise (0.06 +/- 0.02 arbitrary units, p <0.05). In conclusion, strenuous short-term aerobic exercise results in significant increases in plasma LPS levels (endotoxemia) together with increases in markers of oxidative stress. Supplementation with ascorbic acid, however, abolished the increase in LPS and nitrite but led to a significant increase in the ascorbate radical in plasma. The amelioration of exercise-induced endotoxemia by antioxidant pretreatment implies that it is a free radical-mediated process while the use of the ascorbate radical as a marker of oxidative stress in supplemented systems is limited.     

A comparison of the effects of troglitazone and vitamin E on the fatty acid composition of serum phospholipids in an experimental model of insulin resistance

The aim of this study was to investigate the effects of troglitazone (TRO)--a new insulin-sensitizing agent--on some metabolic parameters in an experimental model of hypertriglyceridemia and insulin resistance, hereditary hypertriglyceridemic rats, and to compare its effects with those of vitamin E, an antioxidant agent. Three groups of the above rats were fed diets with a high content of sucrose (70% of energy as sucrose) for four weeks. The first group was supplemented with TRO (120 mg/kg diet), the second one with vitamin E (500 mg/kg diet), and the third group served as the control. Vitamin E supplementation did not lower serum triglycerides (2.42 +/- 0.41 vs. 3.39 +/- 0.37 mmol/l, N.S.) while TRO did (1.87 +/- 0.24 vs. 3.39 +/- 0.37 mmol/l, p < 0.01). Neither TRO nor vitamin E influenced the serum levels of free fatty acids (FFA). Both drugs influenced the spectrum of fatty acids in serum phospholipids--TRO increased the levels of polyunsaturated fatty acids (PUFA) n-6 (36.04 +/- 1.61 vs. 19.65 +/- 1.56 mol %, p < 0.001), vitamin E increased the levels of PUFA n-3 (13.3 +/- 0.87 vs. 6.79 +/- 0.87 mol %, p < 0.001) and decreased the levels of saturated fatty acids (32.97 +/- 0.58 vs. 51.45 +/- 4.01 mol %, p < 0.01). In conclusion, TRO lowered the level of serum triglycerides but vitamin E did not have this effect in hypertriglyceridemic rats. Compared with TRO, vitamin E had a different effect on the spectrum of fatty acids in serum phospholipids.     

Effect of vitamin E supplementation on post-exercise plasma lipid peroxidation and blood antioxidant status in smokers: with special reference to haemoconcentration effect

The oxidative effects were investigated of exhausting exercise in smokers, and the possible protective role of 400 mg day(-1) vitamin E (Vit E) supplementation over a period of 28 days. The subjects exercised to exhaustion including concentric-eccentric contractions following maximal cycling. The haematocrit and haemoglobin, leucocyte (WBC), plasma lactic acid (La) and malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), serum Vit E and ceruloplasmin (CER) concentrations were measured pre and post exercise. Supplementation increased Vit E concentrations 28% and 31% in the controls and the smokers, respectively. Cigarette smoking and/or Vit E supplementation did not influence plasma lipid peroxidation or the antioxidant status at rest. Exercise caused significant haemoconcentration in all groups. When the post-exercise concentrations were adjusted for haemoconcentration, a significant elevation in La concentrations due to exercise was observed in all groups. Similarly, there were significant elevations in the adjusted WBC counts in all groups except the Vit E supplemented controls. The MDA concentrations on the other hand, when adjusted for haemoconcentration, did not exhibit any difference due to exercise. Exercise did not affect the GPx and CER activities either, while causing a SOD activity loss in all groups except the Vit E supplemented non-smokers. Serum Vit E concentrations diminished significantly in all groups after exercise. Post-exercise plasma MDA and blood antioxidant concentrations were not altered by smoking. The results would suggest that plasma volume changes should always be taken into account when assessing post-exercise plasma concentrations and that smoking and exercise do not have an additional collective effect on plasma lipid peroxidation and the dose of Vit E administered was insufficient to maintain the serum concentrations after exercise.     

Defective regulation and action of atrial natriuretic peptide in type 2 diabetes.

Increased plasma atrial natriuretic peptide (ANP) levels and impaired ANP action have been reported in patients with diabetes or insulin resistance. The aim of this study was to assess the interaction between insulin and ANP in type 2 diabetes. In 12 normotensive, normoalbuminuric type 2 diabetics, we infused insulin at a high (6.6 pmol/min/kg) or, on a different day, at a low rate (0.6 pmol/min/kg) during 4 hours of isoglycemia under isovolumic, isoosmolar conditions. The normal response was established in 12 healthy volunteers using an identical protocol. Despite higher baseline ANP levels (17.7 +/- 2.8 vs. 10.8 +/- 1.8 pg/ml, p = 0.04), urinary sodium excretion was similar in diabetics and controls (113 +/- 8.5 vs. 102 +/- 8.8 mEq/24 hours, p = ns). In both groups, hyperinsulinemia caused a decrease in blood volume (0.33 +/- 0.10 l, p < 0.01), diastolic blood pressure (6 %, p < 0.02), and natriuresis. However, plasma ANP decreased in controls (from 12.7 +/- 1.9 to 8.6 +/- 1.4 pg/ml, p = 0.01) but not in type 2 diabetics (15.1 +/- 2.7 vs. 17.2 +/- 3.8 pg/ml, p = ns). We conclude that ANP release is resistant to volume stimulation in type 2 diabetic patients, and natriuresis is resistant to ANP action. This dual disruption of ANP control may play a role in blood pressure regulation in diabetes.     

Dietary fat source and cholesterol interactions alter plasma lipids and tissue susceptibility to oxidation in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats

Due to the potential for dietary fat source to alter plasma lipids and tissue antioxidant status, we hypothesized that blends of saturated, n-6 and n-3 fats with cholesterol would affect LDL and tissue susceptibility to in vitro oxidation. The effects of dietary fat blends of butter (B), beef tallow (T), soybean oil (SBO) or menhaden oil (MO) and cholesterol on systolic blood pressure (SBP), plasma lipoproteins and tissue susceptibility to glutathione (GSH) depletion and lipid peroxidation (TBARS) were examined in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats. SBP in SHRs was higher (p < 0.001) than in WKYs at 13-weeks of age but was not altered by dietary fat or cholesterol. LDL- and HDL-cholesterol were greater (p < 0.001) in WKY than SHR. LDL-cholesterol and (VLDL7- + LDL-cholesterol)/HDL-cholesterol ratios were reduced in MO vs. B, T and SBO groups. HDL-cholesterol levels tended to be lower and greater in B and MO groups, respectively vs. T and SBO groups. Initial LDL fluorescence was greater (p < 0.001) in high- vs. low-cholesterol groups. The change in LDL fluorescence was reduced (p < 0.001) in high-cholesterol groups, and MO vs. B, T and SBO rats. MO fed rats had reduced (p < 0.001) RBC, heart and liver GSH depletion and reduced (p < 0.01) tissue TBARS and RBC MDA production. In summary, a moderate level of dietary MO did not increase tissue and LDL in vitro oxidizability in SHR and WKY rats. High dietary cholesterol exhibited a protective effect against in vitro oxidation of LDL and selected tissues.     

Depression of biliary glutathione excretion by chronic ethanol feeding in the rat

The effects of chronic alcohol feeding on biliary glutathione excretion were studied in rats pair fed diets containing either ethanol (36% of total energy) or isocaloric carbohydrate for 4-6 weeks. An exteriorized biliary-duodenal fistula was established and total glutathione (GSH) and oxidized glutathione (GSSG) were measured. A significant decrease was observed in rats fed alcohol chronically compared to their pair fed controls in the biliary excretion of GSH (55.7 +/- 37.0 vs 243.1 +/- 29.0 micrograms/ml bile, p less than 0.025) as well as biliary GSSG (12.5 +/- 5.0 vs 49.9 +/- 8.0 micrograms/ml bile, p less than 0.05) and in bile flow (23.1 +/- 1.6 vs 29.2 +/- 1.3 micrograms/min, p less than 0.05). An acute dose of ethanol tended to exaggerate the decrease on biliary GSH and GSSG in the two groups of animals. The depression in biliary GSH could not be attributed to decreased GSH synthesis since S35-L-methionine incorporation into hepatic and biliary GSH was unchanged or even increased after chronic ethanol feeding.     

Selenium, glutathione peroxidases, and some other antioxidant parameters in blood of patients with chronic renal failure

In the present study several parameters associated with oxidative stress were examined in the blood of 25 chronic renal failure (CRF) patients and the results were compared with 18 healthy subjects. Mean creatinine concentration in patients was 1,216 +/- 292 micromol/l. Selenium (Se) concentration in red cells, whole blood and in plasma of CRF patients (106 +/- 32.5, 59.0 +/- 16.7 and 42.4 +/- 13.8 ng/ml, respectively) was significantly (0.0001 < P 0.01) lower (by 20-42%) compared with the controls. Red cell and plasma glutathione peroxidase (GSH-Px) activities (16.6 +/- 3.4 U/g Hb and 93.7 +/- 32.9 U/l plasma) were lower by 12 and 53% (P < 0.05 and < 0.0001, respectively) in patients than in healthy subjects. GSH concentration in red cells of patients (2.81 +/- 0.45 mmol/l) was significantly (P < 0.001) higher (by 20%) than in control group. Malonyldialdehyde (MDA) concentration (expressed as thiobarbituric acid-reactive substances) in red cells of patients (725 +/- 155 nmol/g Hb) was significantly (P < 0.001) higher (by 28%) than in control group. No significant difference was observed in the activity of superoxide dismutase in pLasma between the two groups. In conclusion, our results confirm that the aLterations in Se levels in blood components and in GSH-Px activity in plasma show that the kidney plays an important role in Se homeostasis and in plasma GSH-Px synthesis.     

Tetradecylthioacetic acid prevents the inflammatory response in two-kidney, one-clip hypertension

ANG II promotes inflammation through nuclear factor-kappaB (NF-kappaB)-mediated induction of cytokines and reactive oxygen species (ROS). The aim of the present study was to examine the effect of tetradecylthioacetic acid (TTA), a modified fatty acid, on NF-kappaB, proinflammatory markers, ROS, and nitric oxide (NO) production in two-kidney, one-clip (2K1C) hypertension. The 2K1C TTA-treated group had lower blood pressure (128 +/- 3 mmHg) compared with 2K1C nontreated (178 +/- 5 mmHg, P < 0.001). The p50 and p65 subunits of NF-kappaB were higher in the clipped kidney (0.44 +/- 0.01 and 0.22 +/- 0.01, respectively) compared with controls (0.25 +/- 0.03 and 0.12 +/- 0.02, respectively, P < 0.001). In the 2K1C TTA-treated group, these values were similar to control levels. The same pattern of response was seen in the nonclipped kidney. In 2K1C hypertension, cytokines plasma were higher than in control: TNF-alpha was 13.5 +/- 2 pg/ml (P < 0.03), IL-1beta was 58.8 +/- 10 pg/ml (P = 0.003), IL-6 was 210 +/- 33 pg/ml (P < 0.001), and monocyte chemoattractant protein-1 was 429 +/- 21 pg/ml (P = 0.04). In the 2K1C TTA-treated group, these values were similar to controls, and the same pattern was seen in the clipped kidney. Clipping increased 8-iso-PGF-2alpha (P < 0.01) and decreased NO production (P < 0.01 vs. control) in the urine. TTA treatment normalized these values. NO production was also lower in clipped and nonclipped kidney (P < 0.001). After TTA treatment, these values were similar to controls. The results indicate that TTA has a potent anti-inflammatory effect in 2K1C by inhibition of p50/p65 NF-kappaB subunit activation, reduction of cytokines production and ROS, and enhanced NO production.     

Relation of leptin and tumor necrosis factor alpha to body weight changes in patients with pulmonary tuberculosis

In this study we investigated whether leptin and TNFalpha levels change with improvement in body weight with antituberculotic therapy in active tuberculosis patients. 30 patients (8 females and 22 males) with active pulmonary tuberculosis formed the patient group, and 25 sex- and age-matched healthy subjects (8 females and 17 males) served as the control group. Body weight, body mass index (BMI) and serum leptin and plasma TNFalpha levels are measured before and in the sixth month of therapy in all patients. Before the initiation of therapy, BMI of the patients was significantly lower than BMI of the controls (20.2 +/- 1.6 vs. 25.2 +/- 2.7 kg/m(2), respectively; p < 0.05). After treatment, BMI of the patients increased significantly to 21.4 +/- 1.9 kg/m(2) (p < 0.05), but was still lower than that of the controls (p < 0.05). Pretreatment serum leptin (4.5 +/- 0.9 vs. 2.1 +/- 0.2 ng/ml, respectively; p < 0.05) and plasma TNFalpha (27.9 +/- 3.4 vs. 23.9 +/- 3.0 pg/ml, respectively; p < 0.05) levels of the patients were significantly higher than those of the controls. After treatment, serum leptin levels increased to 6.7 +/- 2.2 ng/ml, but this rise was not statistically significant (p > 0.05). Treatment did not result in any significant change in TNFalpha levels, either. Delta leptin was highly related to Delta BMI in patients with tuberculosis (r = 0.68, p = 0.02). In the pretreatment period, there was a significant correlation between leptin and TNFalpha levels in the whole patient group (r = 0.78, p < 0.001), and in female (r = 0.74, p < 0.001) and male patients separately (r = 0.74, p = 0.035). In conclusion, leptin and TNFalpha may be responsible for the weight loss in pulmonary tuberculosis patients, but their levels do not change with improvement in body weight with antituberculotic treatment.