Influence of verapamil on the efficacy of vitamin E in preventing the ischemia-reperfusion-induced biochemical dearrangement in cerebral cortex of rat

The possibility that verapamil (CAS 52-53-9) may intensify the efficacy of vitamin E in preventing the ischemia-reperfusion-caused biochemical dearrangement in rat cerebral cortex was investigated. A daily injection of vitamin E at i.m. dose of 175 mg/kg b.wt. for 7 days prior to subjecting the rats to 1 h bilateral occlusion of the common carotid arteries followed by reperfusion for another 1 h, moderately diminished the ischemia-reperfusion-induced increase in the activity of lactate dehydrogenase and in formation of conjugated dienes as well as in the conversion of xanthine dehydrogenase-->xanthine oxidase in cerebral cortex of rats. However, concomitant injection of verapamil at i.m. dose of 0.68 mg/kg b.wt. 15 min prior to ischemia-reperfusion together with vitamin E pretreatment afforded an elegant combined therapy that effectively abolished the dearrangement caused by ischemia-reperfusion in the above parameters. These results indicated that the protective efficacy of vitamin E against ischemia/reperfusion-induced biochemical dearrangement in cerebral cortex was intensified by concomitant use of verapamil.

Perchloroethylene-induced alterations in glucose metabolism and their prevention by 2-deoxy-D-glucose and vitamin E in mice

The effect of 2-deoxy-D-glucose (2DG) and vitamin E on the alterations in glucose metabolism induced by perchloroethylene (PER) was studied in mice. Oral administration of PER (3 g kg-1 body wt. day-1) in sesame oil for 15 days caused a significant increase in liver weight, degeneration/necrosis of hepatocytes and increase in kidney weight, glomerular nephrosis and degeneration. These changes occurred concurrently with a significant decrease in blood glucose level, elevated activities of hexokinase, aldolase and phosphoglucoisomerase and decreased activity of gluconeogenic enzymes (glucose-6-phosphatase and fructose-1,6-diphosphatase), indicating the sensitivity of liver and kidney as target tissues in PER toxicity. Evidence is presented that both 2DG (500 mg kg-1 body wt. day-1 i.p.) and vitamin E (400 mg kg-1 body wt. day-1 by oral gavage) during concomitant administration prevented most of the above PER-induced biochemical and pathological alterations. These results suggest that early metabolic and pathological perturbations following exposure of PER in mice can provide the basis for its documented potential for chronic effects like cytotoxicity and may be involved in modulation of carcinogenicity.

Vitamin E: hype or hope

Unlike other vitamins, Vitamin E probably has received less attention in the past because humans are not likely to suffer from deficiency disorders. This fat soluble vitamin is available in many foods, is easily stored, and is readily reused by the body. The original research carried out in the 1920s found that a Vitamin E deficiency in rats produced problems in their reproductive capacity. The name given to the substance at that time, "tocopherol," reflects this action as it is taken from the Greek word, "tocos," meaning "to give birth."

Impairment of endothelium dependent relaxation in the diabetic rat heart: mechanisms and implications

An increased oxidative stress has been suggested to contribute to disturbances in the regulation of coronary flow and the increased cardiac risk in diabetes. Using the isolated perfused heart of streptozotocin-diabetic rats we could recently show [21] that the basal and the maximal coronary flow (tested by infusion of sodium nitroprusside) are not altered in diabetes, but that the 5-HT stimulated endothelial dependent increase in coronary flow becomes progressively impaired. This defect of the endothelium dependent vasodilatation was prevented by perfusion of the hearts with superoxide dismutase and pre-treatment of the diabetic rats with tocopherol-acetate. Perfusion of the hearts with indomethacin to inhibit the synthesis of vasoconstricting prostaglandin endoperoxides did not improve the disturbed 5-HT induced, endothelium dependent increase in coronary flow. Furthermore, acute variations of the glucose concentration in the perfusion medium did not affect the coronary flow significantly. In myocardium, the constitutive endothelial NO synthetase was nearly exclusively expressed with the highest activity in endothelium, as determined from experiments using isolated cardiac endothelial cells. The activity of NO synthetase determined by conversion of arginine to citrulline was significantly increased in diabetes. In line with this observation, the concentration of arginine in plasma was reduced, but that of citrulline elevated. Additionally, the renal elimination of nitrite was enhanced in diabetes. These data suggest that the impaired endothelium dependent relaxation observed in the diabetic myocardium is presumably not caused by a diminished synthesis and release of NO, but by an accelerated inactivation of NO by superoxide anions. We suggest that the increased NO generation reflects a compensatory mechanism to balance the enhanced inactivation of NO.

Vitamin E in humans: demand and delivery

How much vitamin E is enough? An established use of supplemental vitamin E in humans is in the prevention and therapy of deficiency symptoms. The cause of vitamin E deficiency, characterized by peripheral neuropathy and ataxia, is usually malabsorption-a result of fat malabsorption or genetic abnormalities in lipoprotein metabolism. Genetic abnormalities in the hepatic alpha-tocopherol transfer protein also cause vitamin E deficiency-defects in this protein cause an impairment in plasma vitamin E transport. Impaired delivery of vitamin E to tissues, thereby, results in deficiency symptoms. Also discussed is the use of supplemental vitamin E in chronic diseases such as ischemic heart disease, atherosclerosis, diabetes, cataracts, Parkinson's disease, Alzheimer's disease, and impared immune function, as well as in subjects receiving total parenterol nutrition. In healthy individuals, a daily intake of about 15-30 mg of alpha-tocopherol is recommended to obtain "optimal plasma alpha-tocopherol concentrations" (30 microM or greater).

Disappearance of skin lipofuscin storage and marked clinical improvement in adult onset coeliac disease and severe vitamin E deficiency after chronic vitamin E megatherapy

A case of adult onset coeliac disease with IgA and severe vitamin E deficiencies, associated with cerebellar impairment and peripheral neuropathy, is described. Nerve conduction velocities, BAERs and SEP were altered. Brain nMR showed cortical atrophy mainly in the frontal and parietal regions. At ultrastructural examination, nerve biopsy showed a severe nerve fiber loss with presence of lipofuscin. Lipofuscin has been also found in skin and muscle biopsy. Duodenal biopsy showed villar atrophy with criptae hypoplasia. IgA, Apo A1 lipoprotein and cholesterol were decreased. Serum level of vitamin E was not detectable and its amount did not increase after an oral loading (2 g bolus). Parenteral vitamin E administration (900 mg/day) was able to normalize the plasma values only after 6 months of chronic administration of the drug in coincidence with a significant improvement of clinical and neurophysiological signs, and disappearance of lipofuscin storage in the skin biopsy.

[Antioxidant system disorder in diabetic patients and the means for its normalization]

The condition was studied on the antioxidant system (AOS)--the activities of catalase, concentration of tocoferoli and reduced glutathione--in 112 patients with type I diabetes mellitus during the course of treatment. It has been established that in decompensation of diabetes mellitus there is a striking deterioration of AOS the degree of which depends upon duration and severity of the illness as well as the presence of angiopathies. Employment in the combined treatment of the donator of sulphhydric groups unithiol and a naturally occurring antioxidant tocopheroli promoted normalization of parameters associated with AOS, diabetic angiopathies included.

Modulation of oxidant stress in vivo in chronic cigarette smokers

BACKGROUND

Free radical-induced oxidative damage is thought to be involved in the pathogenesis of diseases associated with cigarette smoking. We examined the production of 8-epi-prostaglandin (PG) F2 alpha, a stable product of lipid peroxidation in vivo, and its modulation by aspirin and antioxidant vitamins in chronic cigarette smokers.

METHODS AND RESULTS

We performed the following studies: (1) a cross-sectional comparison of smokers and control subjects, (2) an examination of the dose-response relationship, (3) an exploration of the effect of smoking cessation (3 weeks) and nicotine patch supplementation, (4) the effect of aspirin consumption, and (5) the effects of 5 days' dosing with vitamin E (100 and 800 U), vitamin C (2 g), and their combination. 8-epi-PGF2 alpha excretion (in pmol/mmol, mean +/- SEM) was 176.5+/-30.6 in heavy smokers, 92.7+/-4.8 (P<.05) in moderate smokers, and 54.1+/-2.7 (P<.005) in nonsmokers. Urinary levels fell from 145.5+/-24.9 to 114.6+/-27.1 (week 2, P<.05) and 112.6+/-24.9 (week 3, P<.05) on cessation of smoking. Aspirin treatment failed to suppress urinary levels of 8-epi-PGF2 alpha despite a significant reduction in urinary 11-dehydro-TxB2 production and suppression of 8-epi-PGF2 alpha and TxB2 in serum. Vitamin C (pre, 194.6+/-40.9; post, 137.2+/-34.1; P<.05) and a combination of vitamin C and E (pre, 171.0+/-39.8; post, 133.5+/-29.6 P<.05) suppressed urinary 8-epi-PGF2 alpha, whereas vitamin E alone had no effect.

CONCLUSIONS

Urinary 8-epi-PGF2 alpha may represent a noninvasive, quantitative index of oxidant stress in vivo. Elevated levels of 8-epi-PGF2 alpha in smokers may be modulated by quitting cigarettes and switching to nicotine patches or by antioxidant vitamin therapy.

[Vitamin e supplementation in Senegalese children with kwashiorkor]

Kwashiorkor continues to be a major cause of infant mortality in the developing world. It has recently been suggesting that this form of malnutrition is due to oxidizing aggression. Vitamin E is a powerful natural anti-oxidant, and we therefore investigated the extent to which its supplementation in the diet contributed to treating child kwashiorkor. Vitamin E was also administered to children suffering from marasmus. The study was conducted from October 1993 to July 1994 and included 79 children (38 cases of kwashiorkor and 41 of marasmus). The treatment resulted in a 76% success rate, with the best results for marasmus (89.5% cure). However, the supplement did not have any effect on the nutritional status for either the kwashiorkor or marasmus patients. In the kwashiorkor group, the weight increase, after disappearance of edema was 15.2 +/- 4.9 g/kg/d in the supplemented group as compared to 16.4 +/- 3.6 g/kg/d in the control group. The duration of edema along treatment was similar for the two groups (supplemented: 8.6 +/- 3.1 days, control group: 7.1 +/- 3.9 days). Possible reasons for vitamin E supplementation having no effect are discussed.

[The efficacy of using alpha-tocopherol during ftorotan anesthesia]

Halothane monoanesthesia in hypoxia leads to activation of lipolysis with increase in the content of NEFA and POL products. The administration of alpha-tocopherol in a dose of 50 mg/liter in such cases was conductive to a statistically significant decrease in the content of peroxidation products in the blood.

Smoking, plasma antioxidants and essential fatty acids before and after nutratherapy

OBJECTIVE

To study the effect of smoking on plasma antioxidants with and without antioxidant vitamin nutratherapy.

DESIGN

Chronic smokers (n = 10, 16 +/- 4 cigarettes a day) and nonsmokers (n = 17) of both sexes were recruited from patients with arthritis-like symptoms. After baseline studies of plasma antioxidant vitamins Q (ubiquinone) and E (alpha-tocopherol) and essential fatty acids (EFA, vitamin F), three months' nutratherapy with vitamins Q (90 mg) and E (350 mg) was administered and plasma reanalyzed.

RESULTS

No sex differences were seen in smoking habits or plasma nutrients. Smokers had normal Q (0.71 +/- 0.07 mg/L) but depressed E (9.4 +/- 0.6 mg/L, P < 0.01). EFA were the same in both groups. Nutratherapy increased Q by about 90% in both groups and E by 47% in smokers and 101% in nonsmokers (P < 0.01). In nonsmokers, nutratherapy protected omega-3 fatty acids (vitamin F1)-plasma docosahexaenoic acid increased by 39%. The vitamin F index (omega-6:omega-3, ratio) remained unchanged in the smokers but decreased in the nonsmokers and became related to the individual plasma vitamin Q but not to vitamin E.

CONCLUSIONS

There was no difference between smokers and nonsmokers before nutratherapy. Nonsmokers may have suffered from passive smoking. After nutratherapy the quantitatively most important antioxidant, ie, vitamin E, increased more in nonsmokers than in smokers. This resulted in less vitamin F1 peroxidation. Nutratherapy cannot overcome disadvantages associated with smoking. Nonsmokers might achieve an antioxidant protection with nutratherapy, which could mean a possible reduced risk of developing cardiovascular disease.

Treatment of actinic prurigo in Chimila Indians

BACKGROUND

Actinic prurigo has a high prevalence in women of child-bearing age. Its treatment has been, among others, with thalidomide. To avoid the deleterious effects of this drug on the embryo, therapeutic alternatives have been sought. Among these, tetracycline and vitamin E have been investigated as to their influence on the symptoms of actinic prurigo. Both these drugs affect superoxide radicals that are thought to be involved in the pathogenesis of actinic prurigo.

MATERIALS AND METHODS

Patients (Chimila Indians with a high prevalence of actinic prurigo) received either (a) tetracycline, 500 mg three times daily, for 6 months, or (b) vitamin E, 100 IU daily, for 6 months. The patients were seen once monthly. There were eight patients in each group.

RESULTS

Both drugs used were effective. Pruritus was remarkably improved by either treatment. None of the side effects were severe enough to lead to interruption of treatment, but the observation period posttreatment was relatively short, 4 months for tetracycline and 2 months for vitamin E. The improvement occurred in spite of the continuation of extensive exposure to the sun.

CONCLUSIONS

Tetracycline and vitamin E are efficacious in relieving the pruritus of actinic prurigo. Preliminary trials of a combination treatment with these two drugs is a new avenue which has shown in preliminary trials to yield synergistic effects which might allow the dosage of tetracycline to be reduced.

Reduced erythrocyte deformability related to activated lipid peroxidation during the early postburn period

The role of lipid peroxidation in reduced red cell deformability has been examined after thermal injury of rats (full skin thickness over 15-20 per cent of total body surface). An increased concentration of erythrocyte malonyldialdehyde (MDA) and blood thiobarbituric acid (TBA) reactive product levels during the first 3 days after thermal trauma was established. There was a remarkable decrease in red cell superoxide dismutase (SOD) activity after burns and an increase in glucose-6-phosphate dehydrogenase (G-6-PD) on day 3 postburn. The deformability of erythrocytes was diminished significantly during the first 3 days after burns. There was a significant negative correlation between the deformability and the amount of MDA accumulated in erythrocytes (r = -0.92). Both the accumulation of MDA and the reduction of SOD activity in erythrocytes were suppressed by alpha-tocopherol treatment, which also prevented the decrease in erythrocyte deformability. These results suggest that the activation of the peroxidative process is a possible mechanism for the decreased deformability of erythrocytes during the early stage after thermal injury.

Abnormalities of antioxidant metabolism in a case of Friedreich's disease

We report a patient with Friedreich's disease (FD) who exhibited abnormalities of antioxidant metabolism, including decreased levels of glutathione peroxidase, glutathione reductase, and selenium, and an increased lipid peroxide index. These abnormalities became normal after treatment with N-acetylcysteine, selenium, and low-dose vitamin E therapy. Treatment was associated with a decreased rate of clinical decline. FD is a neurodegenerative disorder that may be related to disturbed antioxidant metabolism; the disorder may be treatable with antioxidant compounds.

Safety of antioxidant vitamins

As a result of the many scientific and popular press reports of the benefits of antioxidant vitamins (vitamin A, beta-carotene, vitamin E, and ascorbic acid), it is estimated that 40% of the US population is consuming vitamin supplements. The efficacy of these supplements is not yet proved, and some have questioned their safety. Approximately 10 to 15 cases of vitamin A toxic reactions are reported per year in the United States, usually at doses greater than 100,000 IU/d. No adverse effects have been reported for beta-carotene. The frequency of vitamin E toxic reactions is not well delineated, but case reports are few at dosages less than 3200 mg/d. Ascorbic acid toxic reactions are rare at dosages less than 4 g/d. Despite a lack of clinical trial data, it seems that antioxidant vitamins are safe, although prudence might dictate their avoidance by women of childbearing potential, persons with liver disease or renal dysfunction, and those taking certain medications or undergoing specific laboratory tests.

Long-term oral vitamin E supplementation in cystic fibrosis patients: RRR-alpha-tocopherol compared with all-rac-alpha-tocopheryl acetate preparations

To investigate the efficacy of three different vitamin E preparations for optimizing vitamin E status in cystic fibrosis (CF patients long-term, 29 patients (aged 0.7-29.8 y) were randomly assigned to receive 400 IU of either RRR-alpha-tocopherol (A: 268 mg, n = 10) or all rac-alpha-tocopheryl acetate as a fat-soluble (B: 400 mg, n = 10) or water-miscible preparation (C: 400 mg, n = 9) and were followed for 6 wk. In the whole study group, plasma alpha-tocopherol concentrations increased from baseline (10.5 +/- 4.6 micromol/L) to 3 wk (25.7 +/- 6.5 micromol/L; P < 0.001), but not further between 3 and 6 wk; concentrations at 3 and 6 wk did not differ from those of age-matched control subjects (23.6 +/- 3.9 micromol/L). There was no significant difference in the increase from baseline to 6 wk among preparations A (17.75 +/- 8.43 micromol/L), B (14.0 +/- 9.4 micromol/L), and C (15.5 +/- 7.1 micromol/L). Because of differences in body weight, the dose administered ranged from 5.5 to 47.4 IU x kg-1 x d-1; it correlated positively with the increase in plasma alpha-tocopherol concentrations (P < 0.001). There was no significant difference in the increase in plasma alpha-tocopherol concentrations between patients with CF-associated liver disease (n = 8) who received 10.2 +/- 3.8 IU x kg-1 x d-1 and those without liver disease taking comparable doses. We conclude that CF patients can be efficiently supplemented with 400 IU/d of any one of the three vitamin E preparations and plasma values of healthy control subjects can be achieved.