Serum 25-hydroxyvitamin D predicts severity and prognosis in stroke patients.

BACKGROUND AND PURPOSE: We aimed to evaluate the association between 25-hydroxyvitamin D (25(OH)D) levels and both clinical severity at admission and outcome at discharge in stroke patients. METHODS: From February 2010 to December 2010, consecutive stroke patients admitted to the Department of Neurology of Dijon, France, were identified. Clinical information was collected. Serum concentration of 25(OH)D was measured at baseline. Stroke severity was assessed at admission using the NIHSS score. Functional impairment was evaluated at discharge using the modified Rankin scale (m-Rankin). Multivariate analyses were performed using logistic regression models. RESULTS: Of the 386 recorded patients, serum 25(OH)D levels were obtained in 382 (median value = 35.1 nM; IQR = 21-57.8). At admission, 208 patients had a NIHSS ≤5, with a higher mean 25(OH)D level than that observed in patients with moderate-to-high severity (45.9 vs. 38.6 nM, P < 0.001). In multivariate analyses, a 25(OH)D level in the lowest tertile (<25.7 nM) was a predictor of a NIHSS ≥6 (OR = 1.67; 95% CI = 1.05-2.68; P = 0.03). The mean 25(OH)D level was lower in patients with moderate-to-severe handicap at discharge (m-Rankin 3-6) than in patients with no or mild handicap (35.0 vs. 47.5 nM, P < 0.001). In multivariate analyses, the lowest tertile of 25(OH)D level (<25.7 nM) was associated with a higher risk of moderate-to-severe handicap (OR = 2.06; 95% CI = 1.06-3.94; P = 0.03). CONCLUSION: A low serum 25(OH)D level is a predictor of both severity at admission and poor early functional outcome in stroke patients. The underlying mechanisms of these associations remain to be investigated.

Time course of asymmetric dimethylarginine (ADMA) and oxidative stress in fructose-hypertensive rats: a model related to metabolic syndrome.

OBJECTIVE: Asymmetric dimethylarginine (ADMA) is an endogenous modulator of endothelial function and oxidative stress, and increased levels of this molecule have been reported in some metabolic disorders and cardiovascular diseases. The aim of this work was to analyze the time course of dimethylarginine compounds and oxidative stress levels and the relationship between these and cardiovascular function in fructose-hypertensive rats. METHODS AND RESULTS: 90 male Sprague-Dawley rats were randomized into 2 groups, fed for 3 months with standard (C) chow supplemented or not with fructose (F, 60%). After sacrifice at different weeks (W), the aorta and plasma were harvested to assess the vascular and biochemical parameters. Our work showed that the plasma levels of ADMA in the fructose-fed rats increased after 2 weeks of the diet (1.6 ± 0.3 µM vs. 1.2 ± 0.3 µM, p < 0.05) with no changes in plasma levels of either SDMA or L-arginine and after an increase in glycemia. Levels of vascular oxidative stress, estimated in aortic segments using an oxidative fluorescence technique, were higher in the F group (W2: 1.14 ± 0.2% vs. 0.33 ± 0.02%, p < 0.01). An increase in expression levels of nitrotyrosine (3-fold) and iNOS (2-fold) were noted in the fructose-fed rats. After 1 month, this was associated with a significant increase in NAD(P)H oxidase activity. Concerning vascular function, a 15% decrease in maximal endothelium-dependent relaxation was found in the aorta of the F group. Our work showed that the presence of exogenous L-MMA, an inhibitor of NO synthase, was associated with a significant reduction in endothelium-dependent relaxation in isolated aorta rings of the C group; this effect was not observed in the vessels of fructose-fed rats. CONCLUSION: Our findings suggest that the elevated levels of ADMA observed could in part be secondary to the early development of oxidative stress associated with the development of hypertension.

[Oxidative stress is exacerbated in diabetic patients during cardiopulmonary bypass]. / Exacerbation du stress oxydatif chez les patients diabétiques durant une circulation extracorporelle.

UNLABELLED: Circulation on blood extracorporeally through plastic tubing activates several pathways including systemic inflammation and oxidative stress. These phenomena are suspected to participate to neurological and cardiovascular side effects observed in the patients under cardiopulmonary bypass (CPB). A direct relationship, in diabetic patients, between hyperglycemia and morbidity and mortality has been established. However, it is still unclear whether perioperative hyperglycemia has a direct effect on adverse events in cardiac surgery. The purpose of this study was to determine the influence of hyperglycemia on inflammation and oxidative stress in patients under CPB during cardiac surgery. MATERIAL AND METHODS: Control patients (n=17) and diabetic (type 2) patients (n=13) were included in this study. Blood samples were drawn before, during and after the CPB. Oxidative stress was evaluated in the plasma by direct and indirect approaches. Direct detection of ascorbyl radicals was assessed by electron spin resonance spectroscopy. An index: ascorbyl radical/vitamin C ratio is an indicator of the degree of oxidative stress taking place in the plasma. Oxygen radical absorbing capacity (ORAC) values were used as measurement of antioxidant capacity of the plasma. To determine inflammation profile of patients, we measure the evolution of plasma concentration of interleukin 8 (IL-8). RESULTS: During cross clamping and post-CPB, the index ascorbyl radical/vitamin C is increased; the value of the index is more significant in diabetic patients. Concomitantly, ORAC values decreased in all the patients during cross clamping (p<0.05). Results concerning inflammatory index showed that IL-8 levels increased during the CPB. CONCLUSION: In conclusion, the current study indicates that a systemic oxidative stress occurs during CPB and post-CPB periods and that in patients with type 2 diabetes mellitus, the systemic oxidative stress was increased.

Effect of a swim training on homocysteine and cysteine levels in rats.

The purpose of this study was to investigate the effects of a 8-week of swim training on total plasma homocysteine and cysteine levels in 16 male Sprague-Dawley rats aged 17 weeks. We also evaluated the activity of hepatic cystathionine beta-synthase (CBS), an enzyme involved in the metabolism of Hcy, the concentration of plasma glutathione, taurine, and a fraction of vitamin B6: the pyridoxal 5-phosphate (PLP). After one week of acclimatization, rats were randomly divided into two groups: 8 non-trained (NTR) and 8 trained rats (TR). Following the training period, body weight gain was lower in TR than in NTR. Plasma homocysteine did not differ among groups while significantly lower plasma cysteine and taurine levels were found in TR (157.83 +/- 8.6 micromol/L; 133.01 +/- 9.32 micromol/L; P < 0.05) compared with data of NTR (176.19 +/- 4.9 micromol/L; 162.57 +/- 8.16 micromol/L; P < 0.05). No significant changes in hepatic CBS activity were observed in TR compared with NTR. Moreover, values for plasma glutathione and PLP concentrations were not affected by training.These results indicate that training reduces plasma cysteine and taurine levels whereas it does not modify other studied parameters. Thus, physical training may regulate cysteine metabolism.

[Hyperhomocysteinemia: an independent risk factor or a simple marker of vascular disease?. 1. Basic data]. / L'hyperhomocystéinémie: facteur de risque cardiovasculaire ou simple marqueur ? 1. Données fondamentales.

Recent epidemiological studies have suggested that hyperhomocysteinemia is associated with increased risk of vascular disease. Homocysteine is a sulphur-containing amino acid whose metabolism stands at the intersection of two pathways: remethylation to methionine, which requires folate and vitamin B12 (or betaine in an alternative reaction); and transsulfuration to cystathionine which requires vitamin B6. The two pathways are coordinated by S-adenosylmethionine which acts as an allosteric inhibitor of the methylenetetrahydrofolate reductase (MTHFR) and as an activator of cystathionine beta-synthase (CBS). Hyperhomocysteinemia arises from disrupted homocysteine metabolism. Severe hyperhomocysteinemia is due to rare genetic defects resulting in deficiencies in CBS, MTHFR, or in enzymes involved in methyl cobalamine synthesis and homocysteine methylation. Mild hyperhomocysteinemia seen in fasting condition is due to mild impairment in the methylation pathway (i.e. folate or B12 deficiencies or MTHFR thermolability). Post-methionine-load hyperhomocysteinaemia may be due to heterozygous cystathionine-beta-synthase defect or B6 deficiency. Patients with homocystinuria and severe hyperhomocysteinemia develop arterial thrombotic events, venous thromboembolism, and more seldom premature arteriosclerosis. Experimental evidence suggests that an increased concentration of homocysteine may result in vascular changes through several mechanisms. High levels of homocysteine induce sustained injury of arterial endothelial cells, proliferation of arterial smooth muscle cells and enhance expression/activity of key participants in vascular inflammation, atherogenesis, and vulnerability of the established atherosclerotic plaque. These effects are supposed to be mediated through its oxidation and the concomitant production of reactive oxygen species. Other effects of homocysteine include: impaired generation and decreased bioavailability of endothelium-derived relaxing factor/nitric oxide; interference with many transcription factors and signal transduction; oxidation of low-density lipoproteins; lowering of endothelium-dependent vasodilatation. In fact, the effect of elevated homocysteine appears multifactorial affecting both the vascular wall structure and the blood coagulation system.

[Hyperhomocysteinemia: an independent risk factor or a simple marker of vascular disease? 2. Epidemiological data]. / L'hyperhomocystéinémie: facteur de risque cardiovasculaire ou simple marqueur ? 2. Données épidémiologiques.

Elevated plasma total homocysteine (tHcy) is considered as a risk factor for occlusive cardiovascular disease (CVD). This concept is based on the observations of premature vascular disease in patients with homocystinuria and on the association between tHcy and increased risk of CVD in prospective studies. However, some observations have raised questions about tHcy as a risk factor. First, low risk population based prospective studies tend to indicate a weak association or no association between tHcy and CVD. Second, several traditional risk factors for CVD are associated with tHcy and may confound the relation between tHcy and CVD. Third, the C667T transition of the methylenetetrahydrofolate reductase causes a moderate increase in tHcy but no or only minor increased CVD risk. Thus, only placebo-controlled intervention studies with tHcy-lowering B-vitamins and clinical endpoints can provide additional valid arguments for the debate over whether tHcy is a causal CVD risk factor.

Effects of a direct injection of liposoluble iron into rat striatum. Importance of the rate of iron delivery to cells.

For a better understanding of the role of iron imbalance in neuropathology, a liposoluble iron complex (ferric hydroxyquinoline, FHQ) was injected into striatum of rats. The effects of two modalities of iron injections on brain damage, hydroxyl radical (*OH) production (assessed by the salicylate method coupled to microdialysis) and tissue reactive iron level (evaluated ex vivo by the propensity of the injected structure for lipid peroxidation) were examined. Rapid injection of FHQ (10 nmoles of 5 mM FHQ pH 3 solution over 1-min period) but not that of corresponding vehicle led to extensive damage associated with increased tissue free iron level in the injected region. Conversely, neither lesion nor free iron accumulation was observed after slow FHQ injection (10 nmoles of a 100 microM FHQ pH 7 solution over 1-h period) as compared to corresponding vehicle injection. Production of *OH was induced by slow FHQ injection but not by rapid FHQ injection, probably as a result of in vivo abolition of iron-induced *OH formation by acid pH. Indeed, rapid injection of FAC pH 7 (ferric ammonium citrate, 5 mM in saline) was associated with *OH formation whereas rapid injection of FAC pH 3 did not. Our results identify the rate of iron delivery to cells as an important determinant of iron toxicity and do not support a major role for extracellular *OH in damage associated with intracerebral iron injection.

Vitamin E-coated dialyzer reduces oxidative stress in hemodialysis patients.

The high incidence of cardiovascular disease in hemodialyzed (HD) patients is well established and oxidative stress has been involved in this phenomenon. The aim of our study was to evaluate if a vitamin E-coated dialyzer could offer protection to HD patients against oxidative stress. Sixteen HD patients were successively assessed for one month (i) on a high biocompatible synthetic dialyzer (AN) and (ii) on a vitamin E-coated dialyzer (VE). Blood samples were taken before and after the dialysis session at the end of each treatment period. HD session conducted with the AN dialyzer was responsible for acute oxidative stress, significantly assessed after HD by a decreased plasma vitamin C level and an increased ascorbyl free radical (AFR)/vitamin C ratio used as an index of oxidative stress. Plasma elastase activity, reflecting neutrophil activation, was also increased; soluble P-selectin, reflecting platelet activation, did not show any variation. The use of the VE dialyzer was associated with a less extended oxidative stress compared with the AN membrane: basal vitamin C level was higher, and after the HD session AFR/vitamin C ratio and elastase activity were not significantly increased. Plasma vitamin E levels were not affected. Our study demonstrates that HD is associated with oxidative stress, which can be partially prevented by the use of a vitamin E-coated dialyzer. Our data suggest that this dialyzer may exert a site-specific scavenging effect on free radical species in synergy with a reduced activation of neutrophils.

Postischemic myocardial recovery and oxidative stress status of vitamin C deficient rat hearts.

OBJECTIVE: To investigate the role of vitamin C tissue content as a protective agent during myocardial ischemia-reperfusion injury, we have evaluated the postischemic functional recovery and free radical release of osteogenic disorder Shionogi (ODS) inherently scorbutic rat hearts and compared them to healthy Wistar rat hearts. METHODS: Isolated perfused hearts of ODS or Wistar rats underwent 30 min of a global total normothermic ischemia followed by 30 min of reperfusion. The lipid-soluble spin trap alpha-phenyl N-tert-butylnitrone (3 mM) was perfused upstream of the coronary bed. Functional parameters were recorded and samples of coronary effluents were analysed using electron spin resonance spectroscopy to characterise and quantify the amount of radical species released. RESULTS: From the onset of reperfusion, a large and long-lasting release of alkyl/alkoxyl radicals was detected, with a peak value of 29.0+/-3.2 nM obtained after 13 min, which was associated with a persistent contractile dysfunction. However, ODS rat hearts showed a higher myocardial recovery with lower left ventricular end diastolic pressure (44.34+/-1.74 vs. 55.03+/-1.57 mmHg for Wistar), higher recovery of rate pressure product (12.3+/-1.4 vs. 1.9+/-1.7x10(3) mmHg beats/min for Wistar) and shorter duration of contractile abnormalities during reperfusion (3.7+/-1.0 vs. 20.8+/-5.3 min for Wistar). Moreover, free radical release was identical in ODS rat hearts as compared to control Wistar rats. Ascorbic acid tissue content was significantly altered in ODS rats (31.9+/-3.3 vs. 591.0+/-54.9 mmol/g of tissue for Wistar) but superoxide dismutases, glutathion peroxidases and inducible heat shock protein 70 genes were up-regulated. CONCLUSIONS: This study shows that ascorbic-acid-deficient ODS rat hearts are more resistant to an ischemic insult than control Wistar rats, probably through the development of alternative protective defences, like the induction of heat shock proteins. These paradoxical results raise the question of the relative importance of each endogenous antioxidant in the cardiac resistance to ischemia-reperfusion injury.

Pre-clinical study of the epinephrine-cisplatin association for the treatment of intraperitoneal carcinomatosis.

We have previously shown that intraperitoneal (i.p.) epinephrine enhances tumour penetration and anti-cancer activity of i.p.-administered cisplatin in rats with peritoneal carcinomatosis. Here, we show a direct correlation between the i.p. epinephrine concentration and cisplatin accumulation in rat peritoneal tumour nodules up to a concentration of 5 mg/l. This concentration leads to a maximal 3.7-fold increase of tumour platinum content and a maximal vasoconstriction of the peritoneal and tumour superficial microcirculation when registered by a laser doppler probe. Further, epinephrine half-life was 20.8+/-3.6 min in the peritoneal cavity of two laparotomized pigs. In these animals, epinephrine plasma concentration, heart rate and systolic blood pressure were dependent on the intraperitoneal dose of epinephrine, and life-threatening signs were not observed in either animal. In conclusion, a 5 mg/l concentration of epinephrine could be safely maintained in peritoneal fluid by regular replacement. This concentration is sufficient to maintain a constant vasoconstriction of the peritoneal and tumoral microvascular bed, and enhance the slow diffusion of cisplatin into peritoneal tumour nodules in the course of per-operative intraperitoneal chemotherapy.

Folate status worsens in recently institutionalized elderly people without evidence of functional deterioration.

OBJECTIVE: To follow folate status, hematological and cognitive changes during the first year of institutionalization among elderly subjects. DESIGN: Prospective study. SETTING: Long-stay unit of the Dijon University Geriatric Hospital. SUBJECTS: Twenty women and four men older than 65 years admitted consecutively. MAIN OUTCOME MEASURES: Folate and vitamin B-6 dietary intake was evaluated by a five-day record on admission (day 1 or d 1), at day 45 (d 45), day 90 (d 90), day 135 (d 135), day 180 (d 180), day 360 (d 360). Circulating levels of folate, vitamin B-6, total homocysteine (tHcy), blood counts and cognitive performance were determined in parallel. RESULTS: From d 1 to d 360, mean folate and vitamin B-6 intakes remained below the French RDA and mean folate intakes decreased significantly (delta = 10.2%, p < 0.05). Mean plasma or erythrocyte folate decreased significantly (delta = 33.7%, p <0.05 and delta = -30.2%, p < 0.001, respectively) from d 1 to d 360; no significant change was observed for the other blood parameters. The incidence of folate deficiency increased (8% vs. 37% for plasma folate <6.8 nmol/L and 8% vs. 17% for erythrocyte folate <340 nmol/L) from d I to d 360. Mean plasma pyridoxal 5'-phosphate (PLP) remained <20 nmol/L during the one-year follow-up. There was no difference between genders for plasma tHcy. Although mean plasma tHcy was <14 micromol/L. plasma tHcy was >14 micromol/L in about one-third of the subjects. At each period, 50% or more subjects were anemic (Hct <35% in women and Hct <40% in men), but the anemia was normocytic (MCV <100 fL). Subjects had a moderate dementia at admission, and no change was observed during the study. CONCLUSIONS: Subjects were already vitamin B-6 deficient at admission. Folate status was impaired during the study. Low vitamin intakes were the main cause of vitamin B-6 deficiency and folate status deterioration. Hematology and mental status capacity were not aggravated by folate status deterioration. Plasma tHcy didn't appear to be an earlier predictor of folate deficiency.

Changes in thiamin, riboflavin, niacin, beta-carotene, vitamins, C, A, D and E status of French Elderly Subjects during the first year of institutionalization.

Vitamin status was assessed in 26 recently institutionalized elderly subjects by combining dietary and biochemical measurements of thiamin, riboflavin, niacin, beta-carotene, vitamins C, A, D and E at admission (P1), and 1.5 (P2), 3.0 (P3), 4.5 (P4), 6.0 (P5), 12 (P6) months later. At admission, except for vitamin A, mean vitamin intakes were lower than the 1992 French Recommended Dietary Allowance. Thiamin, vitamins C, A and E status seemed nearly satisfactory as less than one-fourth of the population sample had blood values lower than the cut-off point for thiamin (erythrocyte thiamin pyrophosphate < 0.17 mumol/l), vitamin A (serum retinol < 1.05 mumol/l), vitamin C (serum vitamin C < 11.3 mumol/l) and vitamin E (serum alpha-tocopherol < 9.3 mumol/l) or higher than the cut-off point for thiamin (erythrocyte transketolase activity coefficient > 1.19). Almost half of the subjects for riboflavin, and almost all non supplemented subjects for vitamin D were in risk of vitamin deficiency (46% had an erythrocyte glutathione reductase activity coefficient > 1.19 and 72% had a plasma 25(OH)D3 < 25 nmol/l). During the study, vitamins status remained unchanged for riboflavin, niacin, vitamins A, D and E, improved for vitamin C (P = 0.004) or impaired for thiamin (P = 0.008). Thus, institutionalization seemed to have no effect on riboflavin, niacin, vitamins A, D and E status and a slight effect on thiamin and vitamin C status.

5,10-methylenetetrahydrofolate reductase common mutations, folate status and plasma homocysteine in healthy French adults of the Supplementation en Vitamines et Mineraux Antioxydants (SU.VI.MAX) cohort.

The 677cytosine mutation identified in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene has been frequently associated with an elevated plasma homocysteine concentration. The aim of the present study was to determine the impact of this MTHFR common mutation on plasma and erythrocyte folate (RCF) and plasma total homocysteine (tHcy) concentrations in healthy French adults. A cohort of 291 subjects living in the Paris area and participating in the Supplementation en Vitamines et Mineraux Antioxydants (SU.VI.MAX) study were analysed to assess the impact of MTHFR polymorphism 677C-->T on folate status and plasma tHcy concentration. The frequency of the mutant homozygote for 677C-->T polymorphism (677TT genotype) in the present cohort was 16.8%. There were significant differences in plasma tHcy between 677CC, 677CT and 677TT genotype groups. The RCF concentrations were significantly different between each genotype, the lowest levels being associated with the 677TT genotype. When segregated by gender, no differences in tHcy between homozygous 677TT, heterozygous 677CT and wild-type 677CC genotype groups in women were observed. The fasting tHcy in women was unrelated to the 677C-->T mutation. However, tHcy was significantly increased in men with the homozygous 677TT genotype. We also analysed the possible implication of a second new MTHFR polymorphism (1298A-->C) in subjects with mild hyperhomocysteinaemia (4th quartile of homocysteinaemia; tHcy >11.1 micromol/l). The polymorphism 1298A-->C did not have a notable effect on tHcy or on the RCF levels. Our observations confirm a relatively high frequency of the 677TT genotype in the French population. Women with this genotype did not show the same increase in tHcy observed in men. In the present study dietary folate intake was not measured. Thus, the interaction of dietary folate with the MTHFR genotype in the French population needs further study.

Chronic exercise affects vitamin B-6 metabolism but not requirement of growing rats.

The effect of chronic exercise (forced swimming) on vitamin B-6 status and metabolism was studied in growing male rats fed deficient (0 mg pyridoxine-HCl/kg), suboptimal (2 mg pyridoxine-HCl/kg) or control (7 mg pyridoxine-HCl/kg) diets for 9 wk. Sedentary rats were fed the same diets. Body weight gain was lower in deficient rats than in both other dietary groups. Sedentary rats were heavier than trained rats of all diet groups. Erythrocyte aspartate aminotransferase, urinary 4-pyridoxic acid excretion, blood (plasma and erythrocytes) and tissue B-6 vitamers were measured. Urinary 4-pyridoxic acid, plasma pyridoxal 5'-phosphate and erythrocyte aspartate aminotransferase values of exercised and sedentary rats responded to changes in dietary pyridoxine but were not different from one another. After 9 wk of vitamin B-6 depletion, tissue concentrations of pyridoxal 5'-phosphate and pyridoxamine 5;5'-phosphate were 41-66% and 26-49% lower, respectively, in the deficient groups than in the control groups. Larger percentage differences occurred in plasma than in tissues (95 vs. 22-66%). In liver, pyridoxal 5'-phosphate concentrations were lower, whereas pyridoxal concentrations were higher in trained than in sedentary rats. In gastrocnemius muscle, pyridoxal 5'-phosphate, pyridoxamine 5'-phosphate and total vitamin B-6 concentrations were higher in trained than in sedentary rats. Concentrations of vitamin B-6 compounds in heart, kidneys, brain and adrenals were not affected by training. On the basis of the vitamin B-6-dependent variables measured in this study, we conclude that prolonged exercise affects the metabolism of vitamin B-6, but does not increase the vitamin B-6 requirement in growing rats.

Vitamin B6 and vitamin C status in elderly patients with infections during hospitalization.

We have evaluated whether vitamin B6 and C metabolism may be altered by infection in the elderly. Vitamin B6 and C biochemical status has been assessed for times over a period of 21 days (days 0, 7, 14, and 21) in 18 subjects > or = 75 years. The subjects were divided into 3 groups: group I (8 subjects with acute infection), group II (4 malnourished subjects), and group III (6 control subjects). Vitamin B6 status was determined by plasma pyridoxal-5'-phosphate (PLP) and erythrocyte aspartate aminotransferase activation coefficient (alpha-EAST), and vitamin C status by plasma ascorbic acid. During the 3 weeks, vitamins B6 and C values were significantly different between groups: at days 7 and 14, PLP values were significantly higher in group III than in both groups I and II, and alpha-EAST values were significantly higher in group I than in both groups II and III. Plasma ascorbate values were significantly lower in group I than in both groups II and III. These data suggest that an acute catabolic state like infection may influence vitamin B6 and C metabolism. Nevertheless, more work is needed to assert that vitamin B6 and C supplementation may be useful during infection.