Effect of vitamin E on the response to ischemia-reperfusion of Langendorff heart preparations from hyperthyroid rats

Hyperthyroidism has been reported to decrease heart antioxidant capacity and increase its susceptibility to in vitro oxidative stress. This may affect the heart response to ischemia-reperfusion, a condition that increases free radical production. We compared the functional recovery from in vitro ischemia-reperfusion (Langendorff) of hearts from euthyroid (E), hyperthyroid (H, ten daily intraperitoneal injections of T3, 10 microg/100g body weight), vitamin E-treated (VE, ten daily intramuscular injections, 20 mg/100g body weight) and hyperthyroid vitamin E-treated (HVE) rats. We also determined lipid peroxidation, tissue antioxidant capacity and the tissue capability to face an oxidative stress in vitro. A significant tachycardia was displayed during reperfusion following 20 min ischemia by the hyperthyroid hearts, together with a low recovery of left ventricular developed pressure (LVDP) and left ventricular dP/dt(max). When H hearts were paced at 300 beats/min, the functional recovery (LVDP and dP/dt(max)) was close to 100% and significantly higher than in E paced hearts. At the end of the ischemia-reperfusion protocol, myocardium antioxidant capacity was significantly lower, whereas lipid peroxidation and the susceptibility to in vitro oxidative stress were higher in the T3 treated (H) than in euthyroid rats. The in vitro tachycardic response, the reduction in the antioxidant capacity and the increase in lipid peroxidation were prevented by treatment of hyperthyroid rats with vitamin E (HVE). These results suggest that the tachycardic response to reperfusion following chronic T3 pretreatment was associated with the reduced capability of the heart to face oxidative stresses in hyperthyroidism.     

Role of nitric oxide in the reperfusion induced injury in hyperthyroid rat hearts

We recently reported that hyperthyroidism affects the heart response to ischemia/reperfusion. A significant tachycardia during reperfusion was associated with an increase in the oxidative stress of hearts from T3-treated animals. In the present study we checked the possible role of nitric oxide (NO) in this major stress induced by the hyperthyroid state. We compared the functional recovery from ischemia/reperfusion of Langendorff preparations from euthyroid (E) and hyperthyroid (H, ten daily intraperitoneal injections of T3, 10 microg/100 g body weight) rats, in the presence and in the absence of 0.2 mM Nomega-nitro-L-arginine (L-NNA). At the end of the ischemia/reperfusion protocol (10 min preischemic perfusion, 20 min global ischemia, 30 min reperfusion) lipid peroxidation, antioxidant capacity (CA) and susceptibility to in vitro oxidative stress were determined on heart homogenates. The main effect of hyperthyroidism on the reperfusion functional response was confirmed to be a strong tachycardic response (154% recovery at 25 min reperfusion) accompanied by a low recovery in both left ventricular diastolic pressure (LVDP) and left ventricular dP/dtmax. This functional response was associated with a reduction in CA and an increase in both lipid peroxidation and susceptibility to oxidative stress. Perfusion of hearts with L-NNA per se had small but significant negative chronotropic and positive inotropic effects on preischemic performance of euthyroid rat hearts only. More importantly, L-NNA perfusion completely blocked the reperfusion tachycardic response in the hyperthyroid rats. Concomitantly, myocardium oxidative state (lipid peroxidation, CA and in vitro susceptibility to oxidative stress) of L-NNA perfused hearts was similar to that of E animals. These results suggest that the higher reperfusion-induced injury occurring in hyperthyroid animals is associated with overproduction of nitric oxide.     

Role of nitric oxide in the reperfusion induced injury in hyperthyroid rat hearts

We recently reported that hyperthyroidism affects the heart response to ischemia/reperfusion. A significant tachycardia during reperfusion was associated with an increase in the oxidative stress of hearts from T₃-treated animals. In the present study we checked the possible role of nitric oxide (NO) in this major stress induced by the hyperthyroid state. We compared the functional recovery from ischemia/reperfusion of Langendorff preparations from euthyroid (E) and hyperthyroid (H, ten daily intraperitoneal injections of T₃, 10 μg/100 g body weight) rats, in the presence and in the absence of 0.2 mM N^ω-nitro-L-arginine (L-NNA). At the end of the ischemia/reperfusion protocol (10 min preischemic perfusion, 20 min global ischemia, 30 min reperfusion) lipid peroxidation, antioxidant capacity (C_A) and susceptibility to in vitro oxidative stress were determined on heart homogenates. The main effect of hyperthyroidism on the reperfusion functional response was confirmed to be a strong tachycardic response (154% recovery at 25 min reperfusion) accompanied by a low recovery in both left ventricular diastolic pressure (LVDP) and left ventricular dP/dt_max. This functional response was associated with a reduction in C_A and an increase in both lipid peroxidation and susceptibility to oxidative stress. Perfusion of hearts with L-NNA per se had small but significant negative chronotropic and positive inotropic effects on preischemic performance of euthyroid rat hearts only. More importantly, L-NNA perfusion completely blocked the reperfusion tachycardic response in the hyperthyroid rats. Concomitantly, myocardium oxidative state (lipid peroxidation, C_A and in vitro susceptibility to oxidative stress) of L-NNA perfused hearts was similar to that of E animals. These results suggest that the higher reperfusion-induced injury occurring in hyperthyroid animals is associated with overproduction of nitric oxide.     

Olive oil supplemented with vitamin E affects mitochondrial coenzyme Q levels in liver of rats after an oxidative stress induced by adriamycin.

In this study we have evaluated the supplementation of olive oil with vitamin E on coenzyme Q concentration and lipid peroxidation in rat liver mitochondrial membranes. Four groups of rats were fed on virgin olive, olive plus 200 mg/kg of vitamin E or sunflower oils as lipid dietary source. To provoke an oxidative stress rats were administered intraperitoneally 10 mg/kg/day of adriamycin the last two days of the experiment. Animals fed on olive oil plus vitamin E had significantly higher coenzyme Q and vitamin E levels but a lower mitochondrial hydroperoxide concentration than rats fed on olive oil. Retinol levels were not affected, by either different diets or adriamycin treatment. In conclusion, an increase in coenzyme Q and alpha-tocopherol in these membranes can be a basis for protection against oxidation and improvement in antioxidant capacity.     

Role of vitamin E as a lipid-soluble peroxyl radical scavenger: in vitro and in vivo evidence

Multiple reactive oxygen/nitrogen species induce oxidative stress. Mammals have evolved with an elaborate defense network against oxidative stress, in which multiple antioxidant compounds and enzymes with different functions exert their respective roles. Radical scavenging is one of the essential roles of antioxidants and vitamin E is the most abundant and important lipophilic radical-scavenging antioxidant in vivo. The kinetic data and physiological molar ratio of vitamin E to substrates show that the peroxyl radicals are the only radicals that vitamin E can scavenge to break chain propagation efficiently and that vitamin E is unable to act as a potent scavenger of hydroxyl, alkoxyl, nitrogen dioxide, and thiyl radicals in vivo. The preventive effect of vitamin E against the oxidation mediated by nonradical oxidants such as hypochlorite, singlet oxygen, ozone, and enzymes may be limited in vivo. The synergistic interaction of vitamin E and vitamin C is effective for enhancing the antioxidant capacity of vitamin E. The in vitro and in vivo evidence of the function of vitamin E as a peroxyl radical-scavenging antioxidant and inhibitor of lipid peroxidation is presented.     

Free radical reaction products and antioxidant capacity in beating heart coronary artery surgery compared to conventional bypass

Oxygen-derived free radicals are important agents of tissue injury during ischemia and reperfusion. The aim of this study was to investigate changes in protein and lipid oxidation and antioxidant status in beating heart coronary artery surgery and conventional bypass and to compare oxidative stress parameters between the two bypass methods. Serum lipid hydroperoxide, nitric oxide, protein carbonyl, nitrotyrosine, vitamin E, and β-carotene levels and total antioxidant capacity were measured in blood of 30 patients undergoing beating heart coronary artery surgery (OPCAB, off-pump coronary artery bypass grafting) and 12 patients undergoing conventional bypass (CABG, on-pump coronary artery bypass grafting). In the OPCAB group, nitric oxide and nitrotyrosine levels decreased after reperfusion. Similarly, β-carotene level and total antioxidant capacity also decreased after anesthesia and reperfusion. In the CABG group, nitric oxide and nitrotyrosine levels decreased after ischemia and reperfusion. However, protein carbonyl levels elevated after ischemia and reperfusion. Vitamin E, β-carotene, and total antioxidant capacity decreased after ischemia and reperfusion. Significantly decreased nitration and impaired antioxidant status were seen after reperfusion in both groups. Moreover, elevated protein carbonyls were found in the CABG group. The off-pump procedure is associated with lower degree of oxidative stress than on-pump coronary surgery.     

Antioxidant treatment prevents cardiac protein oxidation after ischemia-reperfusion and improves myocardial function and coronary perfusion in senescent hearts.

Cardiovascular ageing is associated with an increase in cardiac susceptibility to ischaemia and reperfusion and production of reactive oxygen species has been suspected to be responsible for this age-associated particular vulnerability. To determine whether administration of antioxidant treatment could afford some protection against ischaemia and reperfusion during aging, isolated perfused hearts from adult and senescent rats were submitted to normoxia (180 min), prolonged low-flow ischaemia (15% of initial coronary flow;180 min) or low-flow ischaemia/reperfusion (45 min/30 min), without or with antioxidant enzymes (superoxide dismutase+catalase; 50IU/ml). Contractile function and coronary perfusion were measured and protein oxidation was quantitated in left ventricle after normoxia, ischaemia and ischaemia/reperfusion. Protein oxidation was higher in senescent than in adult hearts after ischaemia-reperfusion, in contrast to prolonged ischaemia. During prolonged ischaemia, antioxidant treatment prevented coronary vasoconstriction at both ages and delayed contractile dysfunction in senescent hearts but did not limit protein oxidation. During reperfusion, antioxidant treatment prevented coronary vasoconstriction and protein oxidation at both ages and considerably improved recovery of contractile function in senescent hearts. In conclusion, antioxidant treatment fully protects the senescent heart against ischaemia/reperfusion but not against prolonged ischaemia injury, indicating that oxidative stress plays a central role in the age-associated vulnerability to ischaemia-reperfusion.     

Vitamin E and oxidative stress

Oxidative stress can result from or be enhanced by a large variety of conditions, including nutritional imbalance, exposure to chemical and physical agents in the environment, strenuous physical activities, injury, and hereditary disorders. While many enzymes and compounds are involved in protecting cells from the adverse effects of oxidative stress, vitamin E occupies an important and unique position in the overall antioxidant defense. The antioxidant function of vitamin E is closely related to the status of many dietary components. Vitamin E-depleted animals are generally more susceptible to the adverse effects of environmental agents than supplemented animals. Also, vitamin E supplementation is beneficial to certain groups of the population. However, supplementing vitamin E in experimental subjects maintained on a nutritionally adequate diet does not always provide additional protection. Differential metabolic responses in various organs and differences in experimental conditions often contribute in the discrepancies in the literature. The lack of clear evidence for the occurrence of lipid peroxidation or antioxidant function of vitamin E in vivo can be attributed partly to the presence of active pathways for metabolizing hydroperoxides, aldehydes, and other oxidation products. Specific and sensitive techniques for measuring lipid peroxidation products in biological systems are essential for understanding the role of free radical-induced lipid peroxidation in tissue damage and antioxidant function of vitamin E in vivo.     

Protective antioxidant effect of vitamins C and E in streptozotocin induced diabetic rats

We have investigated the protective effect of vitamin C and E together supplementation on oxidative stress and antioxidant enzyme activities in the liver of streptozotocin-induced diabetic rats, unsupplemented diabetic and control rats. We also determined the levels of both the vitamins and oxidative stress in plasma. Vitamin supplementation in diabetic rats lowered plasma and liver lipid peroxidation, normalised plasma vitamin C levels and raised vitamin E above normal levels. In liver, the activity of glutathione peroxidase was raised significantly and that of glutathione-S-transferase was normalised by vitamin supplementation in diabetic rats. The levels of lipid peroxidation products in plasma and liver of vitamin-supplemented diabetic rats and activities of antioxidant enzymes in liver suggest that these vitamins reduce lipid peroxidation by quenching free radicals.     

A diet high in cholesterol and deficient in vitamin E induces lipid peroxidation but does not enhance antioxidant enzyme expression in rat liver

Expression of antioxidant enzymes (AOE), an important mechanism in the protection against oxidative stress, could be modified by the redox status of the cells. The aim of this project was to evaluate the role of vitamin E deficiency in association with a high-cholesterol diet in the hepatic lipid peroxidation and the expression of AOE. Two groups of 6 male rats were fed with a high-cholesterol or a high-cholesterol vitamin E-deficient diet. All animals were sacrificed at 72 days of treatment. Liver lipid peroxidation index (Malondialdehyde; MDA) and hepatic AOE were evaluated. Total liver RNA was extracted, and the steady state messenger RNA (mRNA) levels of glutathion peroxydase, manganese superoxide dismutase, Cu/Zn superoxide dismutase and catalase were examined by northern blot. After 72 days on the diet, a significant increase in the lipid peroxidation index was observed in the vitamin E deficient group (MDA : 4.45 +/- 0.29 nmol/mg protein versus 3.65 +/- 0.1 nmol/mg protein in vitamin E normal group). Despite this oxidative stress, the activities and mRNA levels of liver AOE were not significantly different in the 2 groups. These preliminary results show that chronic vitamin E deficiency associated with high cholesterol diet is able to increase lipid peroxidation without modulation of AOE expression and activity in the liver. This suggests that beneficial effects of dietary vitamin E are due to a plasma antioxidant effect or a cell mediated action, rather than to a specific modulation of cellular enzymes.     

Cyclopentenosine, major trifunctional crosslinking amino acid isolated from acid hydrolysate of elastin

Young male rats were sacrificed either at rest or immediately after a single bout of swimming lasting either 5 or 8 h. Mitochondrial population, obtained by centrifugation (10,000g for 10 min) from liver homogenates freed from debris and nuclei, was resolved by differential centrifugation into three fractions. Homogenates and mitochondrial preparations were examined for their protein content, oxidative capacity (by cytochrome oxidase activity), peroxidative processes (by thiobarbituric acid reactive substance and hydroperoxide levels), antioxidant status (by reduced glutathione and vitamin E levels and whole antioxidant capacity), and susceptibility to in vitro oxidative stress. In all groups, the antioxidant level was smaller and oxidative capacity, lipid peroxidation, and susceptibility to oxidants were greater in the heavy mitochondrial fraction. Exercise of shorter duration did not significantly affect most of the parameters; only the resulting homogenate glutathione level and susceptibility to oxidative stress decreased and increased, respectively, compared with control values. In contrast, more prolonged exercise was associated with increased lipid peroxidation and susceptibility to oxidative stress and decreased antioxidant levels in all preparations. The contribution of each fraction to the whole mitochondrial population was also modified in that the heavy fraction decreased and light fractions increased. These results suggest that liver antioxidant defence systems are able to withstand oxidative challenge due to low-intensity exercise of moderate duration. In contrast, the free radical production associated with long-lasting exercise causes oxidative injury in cellular components and in particular induces protein degradation in the heavy mitochondrial fraction characterized by higher susceptibility to oxidative stress.     

Side-stream cigarette smoke induces dose-response in systemic inflammatory cytokine production and oxidative stress

Side-stream cigarette smoke (SSCS), a major component of secondhand smoke, induces reactive oxygen species, which promote oxidative damage in tissues and organs. Inflammatory cytokines play an important role in the pathogenesis of atherosclerosis and heart failure. The present 4-month study examined the effect of various chronic SSCS exposure levels on splenic inflammatory cytokine secretion, heart contractile function, and pathology at 60- and 120-min per day, 5 days per week, for a total of 16 weeks. Tissue vitamin E level and lipid peroxide production also were tested to estimate the oxidative stress. The study found that the pro-inflammatory cytokines, interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and IL-1beta, significantly increased in 120-min SSCS-exposed mice. Decreased stroke volume and increased peripheral arterial resistance were observed in mice exposed to 120-min SSCS per day. Heart pathology was only found in 120-min SSCS-exposed mice. Cardiac and hepatic antioxidant vitamin E levels were decreased as a result of oxidative stress. Hepatic lipid peroxides were increased upon 60-min SSCS exposure. The data also demonstrated that the cardiac alpha-tocopherol level has a strong correlation with stroke volume; splenic IL-1beta has a strong negative correlation with stroke volume; splenic TNF-alpha has a very strong negative correlation with stroke volume. In conclusion, SSCS exposure induced systemic inflammatory responses. SSCS exposure also accentuated systemic lipid peroxidation with depletion of cardiac and hepatic antioxidant vitamin E level. Finally, SSCS exposure at 120 min per day decreased stroke volume and increased vascular resistance. Systemic IL-1beta and TNF-alpha production are responsible for heart contractile dysfunction. Free radicals may be responsible for the progression to heart contractile dysfunction induced, in part, by SSCS. Oxidized lipoprotein could contribute to the vascular functional changes. Exploring the mechanism of vascular dysfunction in mice is warranted. A more precise quantification of the smoking exposure dose in mice needs to be determined as well.     

Selenium supplementation and ischemia-reperfusion injury in rats

Cardiac ischemia--reperfusion injury results in oxidative stress and poor physiological recovery. This study examined the amount of lipid and protein oxidation during ischemia-reperfusion to assess the degree of oxidative stress. Selenium supplementation was used to alter the antioxidant status of rats and the recovery of myocardial function post ischemia-reperfusion was investigated. Male Wistar rats were fed diets containing 0, 50, and 1000 microg/kg sodium selenite for 5 weeks, whilst controls received normal rat food containing 240 microg/kg selenium. Langendorff-perfused hearts were subjected to 22.5 min global ischemia and 45 min reperfusion, with functional recovery assessed. Heart tissues were assayed for the presence of lipid peroxides and protein carbonyls and correlated to cardiac recovery. Following ischemia and reperfusion there was a significant increase in both protein oxidation and lipid peroxidation. Hearts from selenium-deficient animals demonstrated higher levels of both protein carbonyls and lipid peroxides and were more susceptible to ischemia-reperfusion injury when compared to controls (38% versus 47% recovery of rate pressure product (RPP)). Selenium supplementation lowered the levels of protein carbonyls and lipid peroxides and resulted in improved recovery of cardiac function post ischemia-reperfusion (57% recovery of RPP). These data suggest that selenium supplementation may provide an effective method for reducing oxidative damage post cardiac ischemia-reperfusion.     

Topically applied vitamin E prevents massive cutaneous inflammatory and oxidative stress responses induced by double application of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mice

Vitamin E (alpha-tocopherol) is a promising chemopreventive and pharmacologically safe agent, which can be exploited or tested against skin cancer. It is an established antioxidant with an ability to ameliorate the UV-induced skin damage and chemically induced inflammation in lungs. However, there are some conflicting reports about its role as a modulator of chemically induced promotion. We evaluated its efficacy in preventing the inflammatory and oxidative stress responses in a double 12-O-tetradecanoylphorbol-13-acetate (TPA) application tumor skin promotion protocol. Double application of TPA was undertaken to produce massive inflammatory and oxidative stress responses. Topical TPA treatment adversely altered many of the marker responses of stage I skin tumor promotion. Vitamin E application 30 min prior to TPA treatment (10 nmol) inhibited induction of hydrogen peroxide, myeloperoxidase (MPO) activity, xanthine oxidase (XO) activity and lipid peroxidation (LPO). Vitamin E also positively modulated altered antioxidants of mouse skin. Histological examination also revealed marked improvement. These results confirm the efficacy of vitamin E against early inflammatory and oxidative stress responses, which are hallmark of tumor promotion and provide rational basis for chemopreventive action of vitamin E in skin cancer.     

PBN spin trapping of free radicals in the reperfusion-injured heart. Limitations for pharmacological investigations

Post-ischemic reperfusion causes cardiac dysfunction and radical-induced lipid peroxidation (LPO) detectable by ESR spin trapping. This study deals with the applicability of the spin trap technique to pharmacological investigations during myocardial reperfusion injury. The use of the spin trap phenylbutylnitrone (PBN, 3 mM) in isolated rat hearts demonstrated the release of alkoxyl radicals (a_N = 1.39 mT, a_H = 0.19 mT) formed particularly within the first 15 min of reperfusion following 30 min of ischemia. The decline of radicals, after 10 min of reperfusion, was accompanied by recovery of function in 80% of the hearts. The radical concentration in the coronary effluent (maximum after 7.5 min) was reduced by the infusion of 1 mM mercaptopropionylglycine (MPG, 2.7 ± 0.5 U/ml, p < 0.001) or 5 M vitamin E (11.7 ± 0.8 U/ml, p < 0.001), compared to the (PBN-containing) control (29.7 ± 4.3 U/ml). Moreover, functional recovery (left ventricular developed pressure, LVDP 91.6 ± 20% of pre-ischemic level, p < 0.05) was improved by the hydrophilic radical scavenger MPG, compared to the (PBN-containing) control (LVDP 50.5 ± 15.7% of baseline). PBN alone led to higher functional recovery (p < 0.05) and reduced VF (duration of ventricular fibrillation; 7.10 ± 0.36 min/30 min, p < 0.05), compared to the untreated (PBN-free) control (LVDP 26.6 ± 11.8%; VF 19.42 ± 3.64 min/30 min). The Ca antagonist verapamil (0.1 M), MPG, and the lipophilic vitamin E showed cardioprotection in the absence of PBN: post-ischemic recovery of LVDP was 25.4 ± 6.8% (p < 0.05), 39.6 ± 12.7% (p < 0.05) and 52.4 ± 2.6% (p < 0.01), respectively, compared to the corresponding untreated control (13.3 ± 6.6%). Whereas verapamil and vitamin E were able to protect the heart when present alone, they offered no additive effect in the presence of PBN. Therefore, PBN can be used to estimate the radical scavenger properties of an agent in the heart. However, because of the protective properties of PBN itself, the results of simultaneous investigations of the effects of other compounds, such as Ca antagonists or lipophilic radical scavengers, on heart function may be limited.     

Metabolic syndrome in the rat: females are protected against the pro-oxidant effect of a high sucrose diet

Metabolic syndrome is more prevalent in men than in women. In an experimental dietary model of metabolic syndrome, the high-fructose-fed rat, oxidative stress has been observed in males. Given that estradiol has been documented to exert an antioxidant effect, we investigated whether female rats were better protected than males against the adverse effects of a high-sucrose diet, and we studied the influence of hormonal status in female rats. Males and females were first fed a sucrose-based or starch-based diet for 2 weeks. In the males, the plasma triglyceride (TG)-raising effect of sucrose was accompanied by significantly lowered plasma alpha-tocopherol and a significantly lowered alpha-tocopherol/TG ratio (30%), suggesting that vitamin E depletion may predispose lipoproteins to subsequent oxidative stress. In males, after exposure of heart tissue homogenate to iron-induced lipid peroxidation, thiobarbituric reactive substances were significantly higher in the sucrose-fed than in the starch-fed rats. In contrast, in sucrose-fed females, neither a decrease in vitamin E/TG ratio nor an increased susceptibility of heart tissue to peroxidation was observed, despite both a significantly decreased heart superoxide dismutase activity (14%) and a significant 3-fold increase in plasma nitric oxide concentration compared with starch-fed females. The influence of hormonal status in female rats was then assessed using intact, ovariectomized, or estradiol-supplemented ovariectomized female rats fed the sucrose or starch diet for 2 weeks. After exposure of heart tissue to iron-induced lipid peroxidation, higher susceptibility to peroxidation was found only in ovariectomized females fed the sucrose diet compared with the starch group and not in intact females or ovariectomized females supplemented with estradiol. Thus, estrogens, by their effects on antioxidant capacity, might explain the sexual difference in the pro-oxidant effect of sucrose diet resulting in metabolic syndrome in rats.     

Effect of Vitamin E and Polyunsaturated Fatty Acids on Cryopreserved Sperm Quality in Bos taurus Bulls Under Testicular Heat Stress

Taurine bulls are highly susceptible to heat stress, leading to increased oxidative stress (OS) and impaired sperm viability. Polyunsaturated fatty acids (PUFAs) supplementation can be an alternative to improve semen quality, which also results in more sperm susceptibility to lipid peroxidation. Moreover, this deleterious effect can be exacerbated in animals affected by heat stress. Vitamin E is a key antioxidant that counteracts lipid peroxidation of sperm membrane caused by OS. Thus, combining PUFAs with vitamin E may improve sperm quality. In this context, this study aimed to evaluate the effect of interaction between PUFAs and vitamin E on sperm quality in Bos taurus bulls under testicular heat stress. Sixteen taurine bulls under testicular heat stress were randomly assigned in four groups: Control, Vitamin E, PUFA, and PUFA?+?Vitamin E. All groups lasted for 60 days. Samples were cryopreserved/thawed and analyzed for motility variables (CASA), membrane and acrosome integrity, mitochondrial activity, susceptibility to oxidative stress, DNA integrity, and sperm-binding capacity. Results showed that vitamin E had a beneficial effect on some sperm characteristics, whereas PUFA supplementation had an adverse effect when the two treatments were evaluated separately. Finally, the association between PUFAs and vitamin E did not improve sperm quality.     

Protective effect of vitamin E on ischaemia-reperfusion injury in ovarian grafts

Ovarian cortical tissue cryopreservation with subsequent autografting is a potential strategy for the preservation of fertility in patients undergoing systemic chemotherapy and pelvic radiotherapy. Non-vascular implants are first subjected to a period of ischaemia before revascularization and are, therefore, vulnerable to ischaemia-reperfusion injury from reactive oxygen species. Ischaemia-reperfusion injury was investigated during the first week after surgery in murine ovarian grafts and human ovarian xenografts in mice with severe combined immune deficiency (SCID) by measuring total lipid peroxides and malondialdehyde concentrations with a colorometric assay. The effects of administering an antioxidant, vitamin E, on these concentrations were also tested. Products of lipid peroxidation were higher in non-supplemented murine autografts compared with control ovaries (P < 0.05), and were significantly reduced on day 3 by vitamin E administration (P < 0.05). Similarly, in human xenografts, there was a significant reduction in lipid peroxidation with vitamin E administration. These results correspond to a significantly greater total follicle survival in the murine grafts of the supplemented group (45 versus 72%; P < 0.05). They suggest that antioxidant treatment improves the survival of follicles in ovarian grafts by reducing ischaemia-reperfusion injury.     

Enhancement of lipid peroxidation and its amelioration by vitamin E in a subject with mutations in the SBP2 gene

Selenocysteine (Sec) insertion sequence-binding protein 2 (SBP2) is essential for the biosynthesis of Sec-containing proteins, termed selenoproteins. Subjects with mutations in the SBP2 gene have decreased levels of several selenoproteins, resulting in a complex phenotype. Selenoproteins play a significant role in antioxidative defense, and deficiencies in these proteins can lead to increased oxidative stress. However, lipid peroxidation and the effects of antioxidants in subjects with SBP2 gene mutations have not been studied. In the present study, we evaluated the lipid peroxidation products in the blood of a subject (the proband) with mutations in the SBP2 gene. We found that the proband had higher levels of free radical-mediated lipid peroxidation products, such as 7β-hydroxycholesterol, than the control subjects. Treatment of the proband with vitamin E (α-tocopherol acetate, 100 mg/day), a lipid-soluble antioxidant, for 2 years reduced lipid peroxidation product levels to those of control subjects. Withdrawal of vitamin E treatment for 7 months resulted in an increase in lipid peroxidation products. Collectively, these results clearly indicate that free radical-mediated oxidative stress is increased in the subject with SBP2 gene mutations and that vitamin E treatment effectively inhibits the generation of lipid peroxidation products.     

Breath alkanes as a marker of oxidative stress in different clinical conditions

We assessed oxidative stress in three different clinical conditions: smoking, human immunodeficiency virus (HIV) infection, and inflammatory bowel disease, using breath alkane output and other lipid peroxidation parameters such as plasma lipid peroxides (LPO) and malondialdehyde (MDA). Antioxidant micronutrients such as selenium, vitamin E, C, beta-carotene and carotenoids were also measured. Lipid peroxidation was significantly higher and antioxidant vitamins significantly lower in smokers compared to nonsmokers. Beta-carotene or vitamin E supplementation significantly reduced lipid peroxidation in that population. However, vitamin C supplementation had no effect. In HIV-infected subjects, lipid peroxidation parameters were also elevated and antioxidant vitamins reduced compared to seronegative controls. Vitamin E and C supplementation resulted in a significant decrease in lipid peroxidation with a trend toward a reduction in viral load. In patients with inflammatory bowel disease, breath alkane output was also significantly elevated when compared to healthy controls. A trial with vitamin E and C is underway. In conclusion, breath alkane output, plasma LPO and MDA are elevated in certain clinical conditions such as smoking, HIV infection, and inflammatory bowel disease. This is associated with lower levels of antioxidant micronutrients. Supplementation with antioxidant vitamins significantly reduced these lipid peroxidation parameters. The results suggest that these measures are good markers for lipid peroxidation.