Benign coxsackievirus damages heart muscle in iron-loaded vitamin E-deficient mice

Several oxidative stressors (dietary selenium deficiency, dietary vitamin E deficiency coupled with fish oil feeding, genetic reduction of glutathione peroxidase activity) allow a normally benign coxsackievirus B3 (CVB3/0) to damage heart muscle in host mice. This study investigated whether dietary iron overload, another oxidant stress, would also permit CVB3/0 to exert a cardiopathologic effect in vitamin E-deficient (-VE) mice. Four groups of mice were fed either a -VE or a +VE diet containing either an adequate or an excessive (30x) amount of iron. After 4 weeks of feeding, the mice were inoculated with CVB3/0 and heart damage was assessed at various times postinfection. Mice fed a diet sufficient in VE with excess iron developed heart damage equivalent to mice fed a diet deficient in vitamin E without excess iron. However, severe heart damage occurred in the group fed a diet deficient in VE with excess iron, which was the most pro-oxidative diet. The highest heart viral titers were found in mice fed the -VE/excessive iron diet. However, the extent of heart damage did not always correlate with the formation of TBARS in liver homogenates. Further research is needed to clarify the role of oxidative stress and iron overload in determining the course of viral infection.     

Interacting nutritional and infectious etiologies of Keshan disease

In 1979, Chinese scientists reported that selenium had been linked to Keshan disease, an endemic juvenile cardiomyopathy found in China. However, certain epidemiological features of the disease could not be explained solely on the basis of inadequate selenium nutrition. Fluctuations in the seasonal incidence of the disease suggested involvement of an infectious agent. Indeed, a coxsackievirus B4 isolated from a Keshan disease victim caused more heart muscle damage when inoculated into selenium-deficient mice than when given to selenium-adequate mice. Those results led us to study the relationship of nutritional status to viral virulence. Coxsackievirus B3/0 (CVB3/0), did not cause disease when inoculated into mice fed adequate levels of Se and vitamin E. However, mice fed diets deficient in either Se or vitamin E developed heart lesions when infected with CVB3/0. To determine if the change in viral phenotype was maintained, we passaged virus isolated from Se-deficient hosts, maintained, we passaged virus isolated from Se-deficient hosts, designated as CVB3/0 Se-, back into Se-adequate hosts. The CVB3/0 Se- virus caused disease in Se-adequate mice. To determine if the phenotype change was due to changes in the viral genome, we sequenced viruses isolated from Se-deficient mice and compared them with the input CVB3/0 virus. Six point mutations differed between the parent strain and the recovered CVB3/0 Se- isolates. When the experiment was repeated using vitamin E-deficient mice, the same 6 point mutations were found. This is the first report of a specific host nutritional deficiency altering viral genotype. Keshan disease may be the result of several interacting causes including a dominant nutritional deficiency (selenium), other nutritional factors (vitamin E, polyunsaturated fatty acids), and an infectious agent (virus).     

Protection of Heme Proteins by Vitamin E, Selenium, and β-Carotene Against Oxidative Damage in Rat Heart, Kidney, Lung and Spleen

Effects of the combination of vitamin E, selenium, and β-carotene on oxidative damage to rat heart, kidney, lung, and spleen were studied by measurement of the production of oxidized heme proteins (OHP) during spontaneous and prooxidant-induced oxidation. Male SD rats were fed with a vitamin E and selenium deficient diet or a diet supplemented with vitamin E, selenium, and β-carotene, Homogenates of heart, kidney, lung, and spleen were incubated at 37°C with and without the presence of bromotrichloromethane (CBrCl₃). The diet supplemented with antioxidants showed a strong protective effect against oxidative damage to heme proteins during the early stages of both spontaneous and CBrCl₃-induced oxidation in contrast to the antioxidant deficient diet. Synergism of multiple antioxygenic nutrients against oxidative damage to various animal tissues is discussed.     

Impact of vitamin E or selenium deficiency on nematode-induced alterations in murine intestinal function

The effects of deficiencies in the antioxidant nutrients, vitamin E and selenium, on the host response to gastrointestinal nematode infection are unknown. The aim of the study was to determine the effect of antioxidant deficiencies on nematode-induced alterations in intestinal function in mice. BALB/c mice were fed control diets or diets deficient in selenium or vitamin E and the response to a secondary challenge inoculation with Heligmosomoides polygyrus was determined. Egg and worm counts were assessed to determine host resistance. Sections of jejunum were mounted in Ussing chambers to measure changes in permeability, absorption, and secretion, or suspended in organ baths to determine smooth muscle contraction. Both selenium and vitamin E deficient diets reduced resistance to helminth infection. Vitamin E, but not selenium, deficiency prevented nematode-induced decreases in glucose absorption and hyper-contractility of smooth muscle. Thus, vitamin E status is an important factor in the physiological response to intestinal nematode infection and may contribute to antioxidant-dependent protective mechanisms in the small intestine.     

Prooxidant diet provides protection during murine infection with Toxoplasma gondii

Toxoplasmosis, particularly toxoplasmic encephalitis, has emerged as a major cause of morbidity and mortality in patients with acquired immunodeficiency syndrome. Patients infected with human immunodeficiency virus typically experience chronic oxidative stress, and concurrent infection with the intracellular parasite Toxoplasma gondii would be expected to further exacerbate this condition. The present study was conducted to determine whether vitamin E and selenium supplementation might be beneficial in a murine model of toxoplasmosis. To investigate the effect of these antioxidants on the severity of parasitic infection. Swiss Webster (SW) or C57Bl/6J mice infected with oocysts of the ME49 strain of T. gondii were maintained on diets containing no vitamin E or selenium, no vitamin E and 8 ppm selenium, 400 IU/kg vitamin E plus 8 ppm selenium, or vitamin E and selenium at the levels present in standard rodent chow (16 IU/kg and 0.2 ppm, respectively). The results of the study showed that increased dietary supplementation with vitamin E and selenium resulted in trends toward increased tissue cyst number, tissue pathology, and weight loss during infection. In contrast, both resistant SW and susceptible C57Bl/6J mice fed a deficient diet (complete absence of vitamin E and selenium) showed the lowest mean numbers of tissue cysts and very little evidence of tissue pathology during chronic infection.     

Dysferlin deficiency confers increased susceptibility to coxsackievirus‐induced cardiomyopathy

Coxsackievirus infection can lead to viral myocarditis and its sequela, dilated cardiomyopathy, which represent major causes of cardiovascular mortality worldwide in children. Yet, the host genetic susceptible factors and the underlying mechanisms by which viral infection damages cardiac function remain to be fully resolved. Dysferlin is a transmembrane protein highly expressed in skeletal and cardiac muscles. In humans, mutations in the dysferlin gene can cause limb‐girdle muscular dystrophy type 2B and Miyoshi myopathy. Dysferlin deficiency has also been linked to cardiomyopathy. Defective muscle membrane repair has been suggested to be an important mechanism responsible for muscle degeneration in dysferlin‐deficient patients and animals. Using both naturally occurring and genetically engineered dysferlin‐deficient mice, we demonstrated that loss of dysferlin confers increased susceptibility to coxsackievirus infection and myocardial damage. More interestingly, we found that dysferlin is cleaved following coxsackieviral infection through the proteolytic activity of virally encoded proteinases, suggesting an important mechanism underlying virus‐induced cardiac dysfunction. Our results in this study not only identify dysferlin deficiency as a novel host risk factor for viral myocarditis but also reveal a key mechanism by which coxsackievirus infection impairs cardiac function, leading to the development of dilated cardiomyopathy.     

The role of antioxidant nutrients in preventing hyperbaric oxygen damage to the retina

Vitamin E and selenium play essential roles in preventing in vivo lipid peroxidation and free radical damage. Hyperbaric oxygen (HBO) treatment adversely affected the electroretinograms (ERGs) of rats fed a diet deficient in both vitamin E and selenium (the basal or B diet) or a diet deficient in vitamin E alone (B + Se diet). After 4 weeks of HBO treatment (3.0 ATA or 100% oxygen, 1.5 hours per day, 5 day/week) rats fed the B diet deficient in vitamin E and selenium for 6 weeks showed decreased (p less than 0.05) a-wave amplitudes, 85 +/- 9 microvolts (microV), n = 11, compared with a-waves recorded (150 +/- 10 microV, n = 21) for age matched rats fed an identical diet for 6 weeks but not treated with HBO. After 15 weeks of HBO treatment, rats fed the B + Se diet deficient in vitamin E alone showed decreased (p less than 0.01) a-wave (61 +/- 9 microV, n = 4) and b-wave (253 +/- 23 microV, n = 4) amplitudes compared with a-wave (115 +/- 7 microV, n = 4) and b-wave amplitudes (450 +/- 35 microV, n = 4) for age matched rats fed the same diet but not treated with HBO. Decreased a- or b-wave amplitudes provide evidence of retinal damage. Rats fed a diet supplemented with vitamin E and selenium or vitamin E alone showed no decreases in either a- or b-wave amplitudes after 15 weeks of HBO treatment.     

Role of antioxidant systems in induced nutritional pancreatic atrophy in chicken

One-day-old chicks were reared using diets differing in their vitamin E and/or selenium content. The purpose of this research was to detect any possible imbalance in the antioxidant defense system, which could be related to development of nutritional pancreatic atrophy. Mitochondrial membranes from animals deficient in both nutrients, or just vitamin E, submitted to peroxidizability ‘in vitro’ had the production of TBARS greatly enhanced. Measurements of the 2-GSH/GSSG ratio suggested that selenium and vitamin E, the latter in higher magnitude, were responsible for maintenance of the reducing capacity of the cell. Enzymatic defense systems against oxidative stress were also studied. The results indicated that the total antioxidant enzymatic activity of pancreatic cells was not sufficient to scavenge all the ROS generated in the nutritionally deficient animals. The present study suggests that nutritional deficiency of selenium and/or vitamin E generates one imbalance between pro-oxidant and antioxidant systems in chicken pancreas, leading to oxidative stress and pancreatic atrophy.     

Vitamin E and selenium regulate balance between beta-adrenergic and muscarinic responses in rat lungs

The effects of hydrogen peroxide on the beta-adrenergic and muscarinic responses of the rat trachea muscle were studied in vitro, after feeding rats, for 6 weeks, either a diet deficient in vitamin E and selenium or a control diet. In the control situation after incubation with 1 mM hydrogen peroxide for 30 min, a reduction of the maximal response to methacholine of 39% occurred whereas no pD2 shift could be demonstrated. Moreover, no response to isoprenaline after precontraction with 3 x 10(-7) M methacholine was left. In the deficient situation, we found a reduction to 64% of the response to methacholine after incubation with 1 mM hydrogen peroxide. Again isoprenaline became inactive, i.e. no relaxation with isoprenaline was observed after precontraction with 3 x 10(-7) M methacholine. We therefore conclude that vitamin E and selenium protect against oxidative stress in lung tissue and thus regulate the (patho-) physiological balance between adrenergic and muscarinic responses.     

Effects of Fermentation Conditions and Aging Temperature on Volatile Ester Contents in Wine

In these present experiments, rats were fed a low casein, vitamin E and selenium deficient diet and were killed at various time intervals up to the occurrence of massive liver necrosis. Liver malondialdehyde, and liver and serum vitamin E levels were analyzed simultaneously with a pathological investigation of the features of the liver and measurement of serum GOT and GPT activities. These investigations were also performed on control rats given a high casein, vitamin E defincient diet or a low casein, vitamin E supplemented diet.

The results show that the liver malondialdehyde level was not increased concomitant with the decrease in liver and serum vitamin E level nor with the occurrence of massive liver necrosis. Liver cells of the rats fed on the low casein, vitamin E deficient diet showed swelling of the cytoplasm at the initial stage, and progressive centrilobular lipid deposition was observed by Sudan III stain.     

饲料硒和维生素E对大鼠机体抗氧化能力的影响

 用克山病病区粮配成基础低硒饲料,补充硒和/或维生素E组成四种不同水平的饲料,饲喂雄性断乳大鼠,观察其对机体抗氧化能力的影响。评价指标是用抗坏血酸诱发的红细胞溶血率、被O~-_2(超氧阴离子)氧化的血红蛋白量和组织中的TBA值。动物饲养13周后,自尾静脉取血,测定溶血率和血红蛋白被氧化的百分率,和全血SeGSHPx(含硒谷胱甘肽过氧化物酶)活力。15周后将动物断头杀死,立即取出心脏和肝脏测定SeGSHPx活力和TBA值。结果表明在克山病病区粮的饲料中补充硒或维生素E,或者二者同时补充均明显提高组织中的SeGSHPx活力和降低组织中的TBA值。不论在硒缺乏时或硒充足时,饲料中补充维生素E显著降低抗坏血酸诱发的红细胞溶血率,对O~-_2氧化血红蛋白无保护作用。在维生素E缺乏时,仅补充硒对溶血无作用。不论饲料中维生素E缺乏或者充足,补充硒对O~-_1氧化血红蛋白均有显著保护作用。     

Protective role of ubiquinone in vitamin E and selenium-deficient plasma membranes.

We have studied the effects of dietary depletion of vitamin E and selenium on endogenous ubiquinone-dependent antioxidant system. Deficiency induced an increase in both coenzyme Q9 and Q10 in liver tissue, reaching a maximum between 4 and 7 weeks of deficient diet consumption. Cytochrome b5 reductase polypeptide was also enriched in membranes after 5 weeks of deficient diet consumption. Substantial DT-diaphorase activity was found in deficient, but not in control plasma membranes. Deficient membranes were very sensitive to lipid peroxidation, although a great protection was observed after incubation with NAD(P)H. Our results show that liver cells can boost endogenous ubiquinone-dependent protective mechanisms in response to deficiency in vitamin E and selenium.     

The effects of in vitro lipid peroxidation on the activity of rat liver microsomal glutathione S-transferase from rats supplemented or deficient in antioxidants

Glutathione S-transferases are a group of multifunctional isozymes that play a central role in the detoxification of hydrophobic xenobiotics with electrophilic centers (1). In this study we investigated the effects of in vitro lipid peroxidation on the activity of liver microsomal glutathione S-transferases from rats either supplemented or deficient in both vitamin E and selenium. Increased formation of malondialdehyde (MDA), a by-product of lipid peroxidation, was associated with a decreased activity of rat liver microsomal glutathione S-transferase. The inhibition of glutathione S-transferase occurred rapidly in microsomes from rats fed a diet deficient in both vitamin E and selenium (the B diet) but was delayed for 15 minutes in microsomes from rats fed the same diet but supplemented with these micro-nutrients (B+E+Se diet). Lipid peroxidation inhibits microsomal glutathione S-transferase and this inhibition is modulated by dietary antioxidants.     

Effect of 3-methylindole on respiratory ethane production in selenium and vitamin E deficient rats

Lipid peroxidation has been proposed as a mechanism of 3-methylindole pneumotoxicity. In this report, lipid peroxidation was measured over 16 h in awake rats given 400 mg/kg i.p. 3-methylindole or its carrier, Cremophore EL. Rats were studied after 8 weeks of feeding a diet either adequate or deficient in vitamin E and selenium. Respiratory ethane production was used as the index of lipid peroxidation. 3-methylindole had no effect on lipid peroxidation for rats fed the adequate diet. For rats on the deficient diet, 3-methylindole suppressed lipid peroxidation by 50% of control. These results indicate that lipid peroxidation is not a mechanism of 3-methylindole pneumotoxicity and support the conclusion that 3-methylindole may act as an antioxidant.     

The effect of selenium and vitamin E on microvascular permeability of rat organs

The effects of dietary sodium selenite and vitamin E on the microvascular permeability of rat organs such as heart, brain, kidney, liver and eye were investigated by using the Evans blue leakage method. Combined deficiency of selenium and vitamin E caused an increase in the permeability of the heart and eye with respect to their controls while it had no considerable effect on the permeability of other organs. On the other hand, toxic levels of selenium (4.2 mg/kg) in diet decreased the permeabilities in kidney, liver, and eye whereas this parameter of brain increased in the same animal group. These results suggested that low or high sodium selenite and vitamin E contents in diet could alter the microvascular permeability of different organs in different manners. It might be important to give reasonable explanations for the pathophysiology of some diseases that are characterized with organ damage and /or disfunction originated from selenium deficiency or toxicity.     

Effect of vitamin E- and selenium-deficiency on rat liver chemiluminescence.

The role of vitamin E and selenium as protective agents against oxidative stress was evaluated by measuring liver chemiluminescence in situ. Weanling rats fed a vitamin E- and selenium-deficient diet showed liver chemiluminescence that was increased 60 and 100% over control values at 16 and 18 days respectively after weaning. At day 21, the double deficiency led to hepatic necrosis, as observed by optical and electron microscopy, and increased serum levels of lactate dehydrogenase and alanine aminotransferase. Single deficiencies, in either vitamin E or selenium, did not produce liver necrosis but increased liver chemiluminescence. Vitamin E deficiency led to a 23 and 50% increase in liver emission at days 18 and 20 respectively; selenium deficiency produced a 64% increase at day 16. The activity of liver selenium-glutathione peroxidase diminished to 13% of the control value in the rats fed doubly deficient and selenium-deficient diets. Activities of superoxide dismutase, catalase and non-selenium-glutathione peroxidase were not modified by the different diets. These results suggest that oxy-radical generation may play a major role in hepatic necrosis in vitamin E- and selenium-deficiency.     

Influence of Diet on Experimental Swine Dysentery. 1. Effects of A Vitamin E and Selenium Deficient Diet Supplemented with 6.8 % Cod Liver Oil

Sixteen growing pigs were fed a vitamin E and selenium deficient diet; half of the animals (Group 2) were given a daily supply of vitamin E and selenium. After having been fed these diets for 53 days, the pigs were infected orally with minced colonic material from cases with typical swine dysentery. This exposure resulted in outbreaks of swine dysentery in both groups. The incubation times were, however, distinctly shorter and the clinical symptoms much more pronounced in Group 1 than in Group 2. The patho^morphological lesions in the colon also differed between the 2 groups. In the pigs of Group 1 evident pseudomembraneous lesions were observed in the spiral colon. In Group 2, the colonic alterations consisted predominantly of a catarrhal enteritis; pseudomembranes occurred in a minor part of colon in only 4 pigs. Both the clinical and the chemical observations and the pathological findings indicated a much better vitamin E and selenium balance in the pigs of Group 2. It is concluded that the treatment with vitamin E and selenium in Group 2 greatly increased resistance to swine dysentery.     

Dietary selenium- and vitamin E-induced alterations in some rabbit tissues

The present study was designed to investigate and compare the effects of dietary selenium (Se) and vitamin E on some physiological parameters and histological changes in liver, heart, and skin tissues, as well as the blood parameters and the related enzymes. Both sex young rabbits were fed with deficient (9.8 μg/kg diet), adequate (225 μg/kg diet), and rich (4.2 mg/kg diet) Se and vitamin E diets for 12–15 wk for this purpose. As the plasma Se levels and the erythrocyte glutathione (GSH) peroxidase activity decreased (79.8±9.4 ng/ml and 2.0±0.3 U/g Hb, respectively) in the deficient group, these values increased (100.4±2.7 ng/mL and 14.5±4.3 U/g Hb) in the rich group significantly with respect to the control group. The other antioxidant enzyme activities and the related element levels did not change significantly in either one of the experimental groups. Although the platelet counts of the two experimental groups were not different from the control values, the collagen and the adenosine diphosphate (ADP) stimulated platelet aggregation rate and intensity increased in the deficient group (p<0.05) and decreased very significantly (p<0.001) in the rich group. In both of the experimental groups, as the percentage values of the neutrophils decreased, the lymphocytes and the eosinophils increased significantly. According to the light microscopic investigations, the observed lesions of considerable intensity within the tissues that elicit cell degenerations were more pronounced in the animals fed with the rich diet than in those fed with the deficient diet. The deficiency as well as toxicity of Se and the deficiency of vitamin E caused several alterations in the physiological functions of the tissues, and these alterations were supported by the histological lesions within these tissues.     

Effect of physical restraint on oxidative stress in mice fed a selenium and vitamin E deficient diet

Physical restraint has been associated with increased oxidative damage to lipid, protein, and DNA. The purpose of this experiment was to determine whether physical restraint would further exacerbate oxidative stress in mice fed a selenium (Se) and vitamin E (VE) deficient diet. Three-week-old mice were fed a Torula yeast diet containing adequate or deficient Se and VE. Menhaden oil was added to the deficient diet to impose an additional oxidative stress. After 4 wk feeding, half the mice in each group were restrained for 5 d in well-ventilated conical tubes for 8 h daily. Mice fed the Se and VE deficient diets had increased liver thiobarbituric acid-reactive substance (TBARS) levels and decreased liver glutathione peroxidase (GPX1) activity and α-tocopherol levels. Plasma corticosterone levels were elevated in restrained mice fed the deficient diet compared to unrestrained mice fed the adequate diet. Restraint had no effect on liver TBARS or α-tocopherol levels. Liver GPX1 activity, however, was lower in restrained mice fed the adequate diet. In addition, liver superoxide dismutase (SOD) activity was lower in the restrained mice fed the adequate or deficient diet. Thus, under our conditions, Se and VE deficient diet, but not restraint, increased lipid peroxidation in mice. Restraint, however, decreased antioxidant protection in mice due to decreased activities of GPX1 and SOD enzymes.