Polyphenolics and fat absorption

OBJECTIVES: To elucidate whether the acute consumption of red wine polyphenolic compounds regulates lipid and lipoprotein metabolism in dyslipidemic postmenopausal women. DESIGN: Eight dyslipidemic postmenopausal women each consumed a mixed meal accompanied by either water, dealcoholized red wine or alcoholic red wine on three separate visits, in a random order, 2 weeks apart. One fasting and six hourly postmeal blood samples were taken and analyzed for plasma apolipoprotein B48 (apoB48; specific marker of chylomicrons (CM) and their remnants (CMR)); total-, LDL- and HDL-cholesterol; triglycerides (TAG); insulin and glucose at each time point. RESULTS: There was a decrease in postprandial apoB48 levels after alcoholic and nonalcoholic red wine consumption compared to water. CONCLUSION: Red wine attenuates postprandial CM and CMR levels in plasma, possibly by delaying the absorption of dietary fat, as suggested by a decrease in plasma apoB48 levels. The reduction of postprandial lipoproteins in circulation after red wine consumption may partly explain the low cardiovascular mortality rates among the French.     

The increase in human plasma antioxidant capacity after red wine consumption is due to both plasma urate and wine polyphenols

By using red wine, dealcoholized red wine, polyphenols-stripped red wine, ethanol-water solution and water, the role of wine polyphenols and induction of plasma urate elevation on plasma antioxidant capacity was examined in humans (n=9 per beverage). Healthy males randomly consumed each beverage in a cross-over design. Plasma antioxidant capacity (measured by ferric reducing antioxidant power, FRAP), ethanol, catechin and urate concentrations were determined before and 30, 60, 90, 120 and 180 min after beverage intake. Dealcoholized red wine and polyphenols-stripped red wine induced similar increase in FRAP values which represented nearly half the effect of the original red wine. This indicates that consumption of red wine involves two separate mechanisms in elevation of plasma FRAP values and both wine phenols and plasma urate contribute to that effect.     

低密度脂蛋白体外氧化修饰过程中几种产物变化的动力学研究

用Ｃｕ＾２＋引发低密度脂蛋白的氧化修饰，研究了低密度脂蛋白氧化修饰过程中脂氢过氧化物，共轭二烯烃，硫代巴比妥酸反应物质琼脂糖凝胶电泳迁移率和荧光物质含量变化的动力学。     

终末期肾病患者脂质过氧化水平的变化

目的 :研究慢性终末期肾病 (ESRD)脂质过氧化状况及肾替代治疗对其的影响。　 方法 :观察对象分为正常对照组、慢性肾功能不全非透析 (CRF)组、持续性不卧床腹膜透析 (CAPD)组和血液透析 (HD)组 ;测定各组以及HD前后血浆丙二醛 (MDA)、脂氢过氧化物 (LOOH)含量和血浆抗氧化型LDL抗体 (anti oxLDLAb)水平。　 结果 :ESRD患者血浆MDA、LOOH和anti oxLDLAb水平均比正常对照组明显升高 (P均 <0 0 5 ) ;CRF组血浆MDA、LOOH和anti oxLDLAb水平与SCr浓度呈正相关 (P均 <0 0 1) ,与Ccr呈负相关 (P均 <0 0 1) ;CAPD组血浆MDA含量比CRF组显著升高 (P <0 0 5 ) ;HD组血浆MDA、LOOH和anti oxLDLAb水平均比CRF组明显增高 ,MDA和LOOH浓度比CAPD组明显升高 (P均 <0 0 5 ) ;单次HD前后上述指标无明显变化 (P均 >0 0 5 )。　 结论 :ESRD患者脂质过氧化反应增强 ,并随肾功能恶化而加重 ,HD可能进一步加剧这种病理生理改变。     

N-3 fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring

OBJECTIVE: We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. DESIGN: Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. MEASUREMENTS: Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitamin A, E and C concentrations, and (iii) antioxidant enzymes activities in erythrocytes. The plasma lipid concentrations and fatty acid composition were also determined. RESULTS: Diabetes increased plasma triglyceride and cholesterol concentrations, whereas macrosomia was associated with enhanced plasma cholesterol and triglyceride levels, which diminished by feeding n-3 PUFA diet. N-3 PUFA diet also reduced increased plasma TBARS and corrected the decreased ORAC values in diabetic rats and their macrosomic offspring. EPAX diet increased the diminished vitamin A levels in diabetic mothers and vitamin C concentrations in macrosomic pups. Also, this diet improved the decreased erythrocyte superoxide dismutase and glutathione peroxidase activities in diabetic and macrosomic animals. CONCLUSION: Diabetes and macrosomia were associated with altered lipid metabolism, antioxidant enzyme activities and vitamin concentrations. N-3 PUFA diet improved hyperlipidemia and restored antioxidant status in diabetic dams and MAC offspring.     

Effect of aminoguanidine on lipid peroxidation in streptozotocin-induced diabetic rats.

Diabetes mellitus is postulated to be associated with increased lipid peroxidation, which may contribute to vascular complications. One potential mechanism of the increased lipid peroxidation in diabetes is lipid-linked advanced glycosylation and oxidation. Aminoguanidine (AMGN), the prototype inhibitor of advanced glycosylation end product (AGE) formation, has been recently shown to prevent oxidative modification of low-density lipoprotein (LDL) in vitro at a moderate concentration. It is unknown whether AMGN may act as an antioxidant against lipid peroxidation under hyperglycemia in vivo. To investigate the in vivo effect of AMGN on lipid peroxidation in diabetes, we administered AMGN (1 g/L in drinking water) or vitamin E (400 mg/d for 5 d/wk) to streptozotocin (STZ)-induced diabetic rats for 9 weeks and measured plasma lipid hydroperoxides by ferrous oxidation with xylenol orange II (FOX method) and red blood cell (RBC) membrane malondialdehyde (MDA) and related aldehydes as thiobarbituric acid-reactive substances (TBARS). Plasma lipid hydroperoxide was higher in STZ-induced diabetic rats versus control rats (mean +/- SD, 7.53 +/- 2.03 v 5.62 +/- 0.44 micromol/L, P < .05; n = 8 to 14). RBC membrane TBARS were also higher in STZ-induced diabetic rats than in control rats (2.67 +/- 0.46 v 1.81 +/- 0.19 nmol/mL, P < .05). Plasma lipid hydroperoxide was lower in AMGN-treated (6.23 +/- 0.59 micromol/L, P < .05) and vitamin E-treated (5.29 +/- 0.27 micromol/L, P < .05) diabetic rats than in untreated diabetic rats. RBC membrane TBARS were also lower in AMGN-treated (1.93 +/- 0.12 nmol/mL, P < .05) diabetic rats than in untreated diabetic rats. There was no significant difference in plasma glucose, cholesterol, and triglyceride levels among diabetic groups. Although the mechanism(s) of action of AMGN on lipid peroxidation in vivo should be studied further, these results suggest that AMGN may have an additional beneficial effect as an antioxidant against lipid peroxidation in a prevention trial for diabetic vascular complications.     

Tea catechin consumption reduces circulating oxidized low-density lipoprotein

It has been reported that green tea consumption reduces the risk of coronary artery disease and cardiac events. Catechin is a major constituent of Japanese green tea and an antioxidant. Lipids and oxidization of low-density lipoprotein cholesterol (LDL-C) play important roles in atherosclerosis. Therefore, we evaluated the effect of catechin intake on the lipid profile and plasma oxidized LDL. The study population consisted of 40 healthy adult volunteers (10 men, 30 women). Catechin was extracted from green tea leaves. The subjects were randomly divided into two groups, a catechin group (n = 29) and a control group (n = 11). In the catechin group, catechin (500 mg: equivalent to 6 or 7 cups of green tea) was administered orally. Venous blood samples were obtained before eating a meal at the start and after 4 weeks without any lifestyle modification. Plasma oxidized LDL assay was performed with a sandwich-type enzyme immunoassay using anti-oxidized phosphatidylcholine monoclonal antibody. The baseline lipid profiles and tea consumptions were similar between the two groups. Plasma oxidized LDL was significantly decreased after catechin administration (from 9.56 +/- 9.2 to 7.76 +/- 7.7 U/mL, P = 0.005), while plasma LDL-C, triglyceride, and HDL-C concentrations did not change. Catechin decreased the plasma oxidized LDL concentration without significant change in plasma LDL concentration. The mechanism of the beneficial effects of green tea on coronary artery disease might result from a decrease in plasma oxidized LDL.     

Nitric oxide metabolites and oxidative stress in mild essential hypertension

Many papers have showed non univocal data about oxidative stress status and nitric oxide metabolites in essential hypertension. Considering this preamble we examined the total antioxidant status (TAS), the lipid peroxidation (LP), expressed as thiobarbituric acid-reactive substances (TBARS), the stable end products of nitric oxide (NOx) and LP/NOx ratio in 25 subjects with untreated mild essential hypertension. The obtained data show a significant increase in TBARS (p < 0.001) and NOx (p < 0.001) in hypertensives and no variation in TAS and in TBARS/NOx ratio. None of these parameters was statistically related to the metabolic parameters or to the blood pressure values. The high level of lipid peroxidation observed in this group of hypertensives suggests the timely and specific employment of antihypertensive and antioxidant agents while the NOx increase seems to confirm the inflammatory status accompanying this clinical condition.     

Effects of white and red wine on endothelial function in subjects with coronary artery disease

BACKGROUND: Levels of anti-oxidant polyphenols are higher in red than in white wine and are thought to contribute to the reduced cardiovascular risk associated with moderate consumption of wine observed in epidemiological studies. AIM: To compare the acute effects of acute ingestion of white and red wine on endothelial function in subjects with coronary artery disease (CAD). METHODS: Fourteen subjects with proven CAD were randomised to consume white and red wine with a light meal in a single blind cross-over study. Flow-mediated dilatation (FMD) of the brachial artery was measured using high-resolution ultrasonography. Endothelial function, lipid profile, plasma alcohol and polyphenols were measured at baseline, 60 and 360 min after wine consumption. RESULTS: At baseline, FMD was similar (white wine 1.6 +/- 1.9%, red wine 1.8 +/- 1.7%). At 360 min after ingestion of wine there was no difference in FMD, which improved nearly threefold after both wines (white wine 4.7 +/- 2.2%, red wine 3.4 +/- 2.9%; P = 0.002). There was no detectable change in plasma polyphenol levels after either wine. CONCLUSIONS: These data suggest that wine acutely improves endothelial function in patients with CAD. This improved endothelial function might contribute to a reduced risk of cardiovascular events.     

Food and red wine do not exert acute effects on vascular reactivity

Experimental hyperglycemia and hyperinsulinemia have been shown to affect vascular reactivity. Chronic red wine consumption is associated with less cardiovascular mortality. Whether ingestion of a natural meal and red wine causes acute changes in vascular homeostasis is poorly understood. The aim of the current study was to clarify whether meal ingestion, with and without red wine, exert acute effects on vascular reactivity in healthy humans. We studied vascular reactivity and forearm nitrite balance in 10 healthy subjects under 3 different circumstances: (1) fasting; (2) after ingestion of a standard natural meal (1,050 kcal); and (3) after the same meal enriched with a glass of red wine. We measured forearm blood flow (FBF) by strain-gauge plethismography during intrabrachial, graded infusion of acetylcholine (ACh), sodium nitroprusside (NP), and norepinephrine (NE). We also measured the forearm balance of nitrite before and during ACh infusion. Despite significant increases in plasma glucose and insulin concentrations, the vasodilatory response to Ach and NP after meal ingestion was not different from the fasting response. Similarly, the vasoconstrictory response to NE was similar postprandially and during fasting. Addition of red wine did not modify the response to any of the vasoactive agents. Finally, the forearm nitrite production during Ach infusion was not different in the 3 experimental settings. Food intake, whether associated or not with red wine, does not affect vascular reactivity in normal human subjects.     

Clinicopathological significance of lipid peroxidation in carotid plaques

Several reports have suggested an association between lipid peroxidation and human carotid atherosclerosis, but few reports have demonstrated a link between lipid peroxidation and carotid plaques in humans. In this study, we investigated the relationship between clinical features, histopathological characteristics and lipid peroxidation in patients undergoing carotid endarterectomy (CEA). Forty-one carotid plaques were obtained. A portion of the most severe lesions was subjected to histopathologic examination, and the remainder of the plaques examined for lipid peroxidation. Thiobarbituric acid-reactive substances (TBARS) values were determined as a marker for lipid peroxidation. The lipid-rich core (LC) and macrophage infiltration (Mφ) component as a percentage of total plaque area were measured morphometrically. Based on the results, all plaques were classified into four groups. Group I (GI): LC <10%; Group IIa (GIIa): LC 10–30%, Mφ <5%; Group IIb (GIIb): LC 10–30%, Mφ ≥5%, and Group III (GIII): LC ≥30%. The plaque TBARS values of GIII were significantly higher than those of GI, GIIa, and GIIb. The TBARS values of GIIb were one-and-a-half times higher than those of GIIa. Our results show that lipid peroxidation in carotid plaques is significantly associated with carotid atherosclerosis, especially plaque instability. These findings provide direct evidence of an association between lipid peroxidation and human atherosclerosis.     

Acute effect of drinking red and white wines on circulating levels of inflammation-sensitive molecules in men with coronary artery disease

There is evidence that moderate consumption of red wine with its high content of polyphenolic antioxidants may be more protective than white wine against development of coronary artery disease (CAD). The aim of this study was to compare the acute effects of ingestion of red wine and white wine on markers of inflammation in men with CAD. Thirteen men with angiographically-proven CAD were studied in a cross-over trial. The men consumed 4 mL/kg (2 to 3 glasses) red wine and white wine in random order during a light meal and with at least a week between interventions. Later, the men also consumed an isoenergetic nonalcoholic beverage (control) in the same study protocol. Venous blood was taken at baseline, 1 hour, and 6 hours after the drinks. Plasma interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), blood alcohol, plasma lipids, and plasma polyphenols were measured. Mean +/- SD blood alcohol was 6.5 +/- 2.2 mmol/L and 6.9 +/- 1.1 mmol/L at 1 hour and returned to baseline at 6 hours after intake of red wine and white wine, respectively. Plasma IL-6 concentration increased significantly (P =.01) during 6 hours after ingestion of red wine (56%) and white wine (63%). The increase in plasma IL-6 concentration after ingestion of wine was significantly higher (P =.045) compared with the corresponding increase (11%) following intake of the nonalcoholic beverage. Plasma IL-6 levels at 6 hours (r =.631, P =.02) were correlated significantly with plasma alcohol levels at 1 hour after ingestion of red wine. These data suggest that moderate wine intake may acutely increase plasma levels of IL-6 in men with CAD. It is possible that this increase in plasma IL-6 is a response to alcohol-induced oxidative stress in the liver.     

Oxidative stress in obstructive sleep apnoea.

AIMS: Any sustained elevation of oxidative stress in patients with obstructive sleep apnoea (OSA) might help explain their increased risk for cardiovascular diseases. We tested the hypothesis that measures of oxidative stress are increased in otherwise healthy subjects with OSA when compared to closely matched OSA-free control subjects. METHODS AND RESULTS: Plasma indices of oxidative stress and lipid peroxidation [thiobarbituric acid-reactive substances (TBARS), oxidized LDL (oxLDL), isoprostanes] were measured in 41 moderate-severe OSA males without other diseases and in 35 matched controls first before sleep, then after 4 h of untreated OSA, and again in the morning after 4 h of effective treatment with continuous positive airway pressure (CPAP). Plasma levels of oxLDL, TBARS, and isoprostanes in OSA patients (n=34, 26, 17, respectively) were comparable to the controls (n=28, 27, 15 for the three markers, respectively). Neither untreated OSA nor CPAP treatment nor normal sleep affected levels of any of the three measures of oxidative stress. There was no association between the severity of sleep apnoea and any measure of oxidative stress. CONCLUSION: Otherwise healthy OSA patients, without any other co-morbidities, do not manifest evidence for higher oxidative stress and lipid peroxidation. Thus, oxidative stress and lipid peroxidation do not appear to be key mediators of increased cardiovascular disease in OSA patients.     

The effect of acute red wine polyphenol consumption on postprandial lipaemia in postmenopausal women

Postprandial lipoproteins are potentially atherogenic. The aim of this study was to elucidate whether acute consumption of red wine (RW) and dealcoholised red wine (DRW) regulates postprandial lipid and lipoprotein metabolism in 17 dyslipidaemic postmenopausal women. A mixed meal accompanied by either water, RW or DRW was consumed on three separate visits, in random order, 2 weeks apart. One fasting and 6 hourly postprandial blood samples were taken for lipid analysis. Results showed no significant quantitative changes in postprandial apolipoprotein (apo) B48 levels following the consumption of DRW or RW compared to water. However, qualitatively, DRW may reduce arterial exposure to apoB48-containing lipoproteins over the 6-h postprandial period measured. DRW consumption did not significantly change postprandial TG or insulin levels. A 35% (p = 0.02) increase in postprandial triglyceride (TG) levels and a 54% (p = 0.02) increase in insulin levels were observed following RW consumption, compared to water. In conclusion, acute DRW consumption had no effect on postprandial lipid and lipoprotein metabolism in dyslipidaemic postmenopausal women. However, the consumption of full-compliment RW exacerbated the postprandial lipaemic and insulin response over the 6-h period. Collectively, our findings suggest that neither polyphenols nor red wine reduce atherosclerotic risk by acutely modulating postprandial lipaemia over a 6-h period.     

Therapeutic effects of tender coconut water on oxidative stress in fructose fed insulin resistant hypertensive rats

ObjectiveTo investigate whether tender coconut water (TCW) mitigates oxidative stress in fructose fed hypertensive rats.MethodsMale Sprague Dawley rats were fed with fructose rich diet and treated with TCW (4 mL/100 g of body weight) for 3 subsequent weeks. Systolic blood pressure was measured every three days using the indirect tail cuff method. At the end of the experimental period, plasma glucose and insulin, serum triglycerides and free fatty acids, lipid peroxidation markers (MDA, hydroperoxides and conjugated dienes) and the activities of antioxidant enzymes were analyzed in all the groups.ResultsTreatment with TCW significantly lowered the systolic blood pressure and reduced serum triglycerides and free fatty acids. Plasma glucose and insulin levels and lipid peroxidation markers such as MDA, hydroperoxides and conjugated dienes were significantly reduced in fructose fed rats treated with TCW. Activities of antioxidant enzymes are up regulated significantly in TCW treated rats. Histopathological analysis of liver showed that TCW treatment reduced the lipid accumulation and inflammatory infiltration without any significant hepatocellular damage.ConclusionsThe overall results suggest that, TCW treatment could prevent and reverse high blood pressure induced by high fructose diet probably by inhibition of lipid peroxidation, upregulation of antioxidant status and improved insulin sensitivity.     

Lipid peroxidation in type 2 diabetes: relationship with macrovascular disease?

Background: Macrovascular disease is the leading cause of death in diabetes. The increased risk of atherosclerosis in diabetes may be partly explained by increased lipid peroxidation.Methods: We assessed lipid peroxidation in subjects with type 2 diabetes with (n=23) and without (n=23) macrovascular complications versus healthy age-matched controls (n=13). The diabetic groups were matched for glycemic control (mean HbA_1c=9%), and for age and had similar known duration of diabetes.Results: Plasma TBARS were comparable between diabetic subjects with and without macrovascular complications (1.89±0.32 and 1.81±0.28 μmol/l) and elevated compared to healthy controls (1.64±0.26 μmol/l, p=0.025). Ratios of IgG and IgM antibodies to oxidized vs. native LDL were comparable between diabetic subjects and controls, and also between diabetic subjects with or without macrovascular complications. The lag phase, an index of the resistance of LDL to oxidation, was significantly longer in diabetic patients with macrovascular complications (66±8 min) vs. those without macrovascular complications and controls (resp. 59±7 and 56±7 min, p<0.05). An explanation may be the frequent use of drugs with possible antioxidant potential, e.g. beta-blocking agents, ACE-inhibitors and calcium entry blockers by these patients. Surprisingly, plasma vitamin E levels were higher in diabetic subjects.Conclusions: We found no evidence of increased lipid peroxidation in diabetic subjects with macrovascular complications, but an increased resistance to oxidation in this group, probably due to an altered antioxidant status. The increased TBARS level in diabetic subjects contrasts with the other indices of lipid peroxidation and may be related to prevalent hyperglycemia and should therefore be interpreted cautiously.     

Increased oxidative stress in acute exacerbations of asthma.

Oxidant-antioxidant imbalance may play an important role in the pathogenesis of asthma, especially during acute exacerbations. To compare the systemic oxidant-antioxidant status in patients with acute exacerbations and stable asthma, we measured a wide range of parameters of oxidant-antioxidant balance in leukocytes, plasma, and red cells of 32 patients with acute exacerbations and 97 patients with stable asthma. These included measurement of superoxide anion generation by leukocytes, lipid peroxidation (measured as TBARS), total nitrates and nitrites, protein carbonyls, and protein sulfhydryls in plasma. Antioxidant status was evaluated by measuring the red cell superoxide dismutase and catalase activity, total blood glutathione, glutathione peroxidase activity in red cell and plasma, and total antioxidant capacity (assessed as ferric reducing antioxidant power) in plasma. Plasma total antioxidant capacity and total protein sulfhydryls were found to be decreased (p < 0.01), whereas plasma lipid peroxides were found to be increased (p < 0.05), in acute exacerbations of asthma. No significant differences were found in plasma glutathione peroxidase, protein carbonyls, and total nitrates and nitrites, red cell antioxidative enzyme activities, superoxide anion release from leukocytes, and total blood glutathione between the two groups (p > 0.05). Our observations suggest that acute exacerbations of asthma are associated with increased oxidative stress that is evident from some of the parameters in the plasma. Failure to observe simultaneous changes in all parameters of oxidative stress may be due to the possibility of their responses being dissociated in time or compensatory changes occurring in some of these.     

Effects of red wine on endothelial function: Postprandial studies vs clinical trials

AimsThere are several epidemiological studies suggesting that moderate daily consumption of red wine may reduce cardiovascular risk. Additionally, results from a great number of in vitro studies indicate that constituents found in red wine are responsible for quite a few beneficial effects on endothelial cells. However, comparison of postprandial studies and clinical trials concerning red wine consumption leads to controversial results about its effect on endothelial function and especially flow-mediated dilatation (FMD).Endothelial function is an early indicator of atherosclerosis and vessel damage and at the same time, it is an independent prognostic factor for cardiovascular risk. Therefore, it is very important to investigate the known acute postprandial effects of red wine consumption, which is highly advised by dieticians and doctors, especially in high-risk populations, such as patients with coronary artery disease (CAD).Data synthesisThis is a review of studies investigating acute and short-term effects of red wine on endothelial function, as well as relevant in vitro studies.ConclusionAnalysis of all data about the acute effects of red wine constituents on endothelial function, is inconclusive and it is obvious that new studies are necessary in order to elucidate this matter. Undoubtedly, one should be very careful in suggesting red wine consumption in high-risk populations, as its acute postprandial effect is not yet clear.     

Tumor necrosis factor soluble receptor p55 and lipid peroxidation in patients with acute alcoholic hepatitis

OBJECTIVES: In experimental models, liver injury induced by ethanol, cytotoxic activity of tumor necrosis factor (TNF) -alpha is principally mediated by TNF receptor p55 (TNFRp55). Among the various mechanisms underlying the toxic effects of TNF-alpha, overproduction of reactive oxygen species seems to play a key role in mediating TNF-alpha-induced cytotoxicity. The aim of this study was to evaluate, in patients with alcoholic liver disease, whether alcohol TNFRp55-mediated hepatotoxicity could account for lipid peroxidation expressed by significant increase in serum thiobarbituric reactive acid substances (TBARS) content, and could be amplified by decrease in blood total glutathione content and decrease in plasma antioxidant protective capacity. METHODS: We studied 27 patients with histological alcoholic liver disease (five fibrosis, six acute alcoholic hepatitis (AAH) without cirrhosis, four cirrhosis without AAH, and 12 cirrhosis with AAH. TNFsRp55 and TNFsRp75 plasma levels were measured using ELISA assays. Plasma lipid peroxidation was evaluated by the content of TBARS. Total glutathione (tGSH) content in blood was determined by a kinetic assay. The sensitivity of erythrocytes to an oxidative stress and the plasma antioxidant protective capacity were simultaneously determined by a simple method. RESULTS: In the 18 patients with mild or severe AAH, the plasma levels of TNFsRp55 were negatively correlated with tGSH and were positively correlated with TBARS, with total bilirubin and with discriminant function. tGSH was positively correlated with plasma selenium. The plasma levels of TNFsRp75 were positively correlated with TBARS and with total bilirubin. There was no significant correlation with the mean inhibitory 50% plasma volume or with the percentage of hemolyzed erythrocytes. CONCLUSIONS: Our data support the notions that, in patients with AAH, TNFsRp55 probably mediates cytotoxicity of TNF-alpha, and that cytotoxic effect could be amplified by tGSH depletion in enhancing lipid peroxidation.     

Effect of sex hormones on lipid peroxidation in women with polycystic ovary syndrome, healthy women, and men.

Recently, the influence of free radicals and lipid peroxides on many diseases, the effect of sex hormones on lipid peroxidation and antioxidant effects of estrogens have received considerable interest. In the present study we aimed to investigate the relationship between sex hormones and both lipid peroxidation and glutathione content in women with polycystic ovary syndrome (POS), in healthy women and in healthy men. We measured levels of lipid peroxides and sex hormones in plasma and levels of glutathione in erythrocytes of all cases. We evaluated the level of thiobarbituric acid reactive substances (TBARS) as an index of lipid peroxides and erythrocyte glutathione level as an index of antioxidant. We found that plasma levels of free testosterone, dehydroepiandrosterone sulfate (DHEAS) and estradiol significantly higher in the women with POS group than in the healthy women group. There was no significant difference in the levels of both plasma TBARS and erythrocyte glutathione, between women with POS group and healthy women group. Plasma DHEAS levels of healthy men and women with POS were similar. Plasma TBARS level was higher and erythrocyte glutathione level was lower in the healthy men group than in both the healthy women group and in the women with POS group. These data imply that testosterone has an oxidant effect. DHEAS which is an antioxidant, has a protective role in females with POS. Estrogens have an antioxidant effect but this action changes according to its dominant degradation pathway.