Effect of C677T methylenetetrahydrofolate reductase gene polymorphism on plasma homocysteine levels in ethnic groups

The objective of this study was to examine plasma homocysteine levels and C677T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in two ethnic groups from Slovakia. The samples consisted of general Slovak-Romany population (68 men and 81 women) from Southwestern Slovakia and the Slovak-Caucasians (174 men and 177 women) who participated in the CINDI project. The homocysteine levels were examined by HPLC, the analysis of MTHFR genotypes was done by PCR. The Slovak-Romany men (12.0+/-5.6 (S.D.) micromol/l) and women (9.2+/-2.6 microol/l) have significantly lower plasma homocysteine levels (p<0.024 and p<0.00001) when compared to Caucasians (13.3+/-5.1 micromol/l in men and 11.3+/-4.3 micromol/l in women). The genetic equilibrium is assumed for the gene frequencies of the MTHFR polymorphism in both samples. The distribution of MTHFR genotypes did not differ between the two populations (TT 13 vs. 10.6 %; CT 46.6 vs. 41.7 %; CC 40.4 vs. 47.7 %, chí(2)2 = 2.315, df=2, ns). The effect of MTHFR genotypes on homocysteine levels was not confirmed in the Slovak-Romanies and TT homozygosity significantly increased plasma homocysteine levels only in Slovak-Caucasians (11.5+/-4.4 micromol/l, ns; vs. 14.8+/-4.8 micromol/l, p 0.002, respectively). To our knowledge, this is the first epidemiological study in the Romany population examining distribution of the MTHFR genotypes and their effect on homocysteine levels. Further studies are needed to establish the variety of cardiovascular risk factors among Romanies in order to evaluate the significance of particular factors.     

Betaine analogues alter homocysteine metabolism in rats

Glycine betaine supplementation lowers homocysteine levels in homocystinuria and in chronic renal failure patients through methylation catalysed by betaine-homocysteine methyltransferase (BHMT). The aim of this study was to determine the effect of glycine betaine analogues on homocysteine metabolism in Lewis rats. Glycine betaine, proline betaine, trigonelline, dimethylsulfoniopropionate (DMSP) or dimethylthetin (1.5 mmoles) was subcutaneously administered to rats fed a low betaine diet. The effect of each betaine on total plasma homocysteine and urinary and plasma betaine concentrations was monitored for 24h following administration. Baseline plasma homocysteine was 8.5 +/- micromol/l (S.E.M., n=44) and compared to controls concentrations decreased following glycine betaine (0.8+/-0.4 micromol/l, P = 0.064), DMSP (1.0+/-0.5 micromol/l, P = 0.041) and dimethylthetin (1.5 +/- 0.7micromol/l, P = 0.033) treatment, while concentrations increased following proline betaine (2.24 +/-0.7micromol/l, P = 0.002) and trigonelline (1.6 +/-0.3 micromol/l, P < 0.001) treatment. The effect of glycine betaine, DMSP and dimethylthetin on circulating homocysteine concentrations was thought to be mediated by BHMT in vivo. This hypothesis was supported by the finding that circulating glycine betaine concentrations increased following DMSP and dimethylthetin treatment. Proline betaine and trigonelline appeared to be poor BHMT substrates, being largely excreted in the urine unchanged, yet increased circulating homocysteine levels. This suggests they are inhibitors of BHMT. Urinary excretion of glycine betaine increased following treatment with all betaines, suggesting that the resorption of glycine betaine in the kidney was inhibited. The study shows that glycine betaine analogues have multiple effects on homocysteine metabolism (250).     

Liquid chromatographic determination of total homocysteine in blood plasma with photometric detection

A rapid and sensitive method for quantification of homocysteine total forms and glutathione levels in blood plasma via HPLC was developed. Dithiotreitol as a water soluble agent has been used as a reductant for both protein and nonprotein disulphides. Dithiotreitol reacts with the mixed disulphides under 60 degrees C treatment within 10 min. Reduced aminothiols and homocystein were easily derivated with 5,5'-dithiobis-(2-nitrobenzoic acid) and the resultant ultraviolet absorbance within 330 nm was detected by the HPLC method. The concentration of total plasma homocysteine was significantly higher in groups of patients: with the end stage of renal disease: 45.5+/-40.9 micromol/l (n=79), with cerebral vascular disorders 12.3+/-7.0 micromol/l (n=65), and with coronary atherosclerosis 15.4+/-10.9 micromol/l (n=15) than that in healthy subjects (6.2+/-1.74 micromol/l, n=20). Some major advantages of the method include: simultaneous measurement of both total homocysteine and total glutathione, no loss of oxidized form during processing of blood plasma for aminothiols measurement, use of protein-bound aminothiols solution as a calibrator.     

Prospective evaluation of folic acid supplementation on plasma homocysteine concentrations during weight reduction: a randomized, double-blinded, placebo-controlled study in obese women

Elevated total homocysteine concentrations and obesity are both associated with an increased risk of cardiovascular disease. However, previous studies of weight reduction on serum homocysteine concentrations have obtained inconsistent reports. We investigated the effect of folic acid supplementation on serum homocysteine concentrations via a randomized, double-blinded, placebo-controlled study. Seventy-four obese women [age (mean +/- SEM) 41 +/- 1 years; body mass index, 29.6 +/- 0.5 kgs/m2] completed a 12 weeks weight reduction program with dietary advice and light exercise. They were also randomized to take either folic acid supplementation (5 mg daily, n = 36) or placebo (n = 38) groups. This program led to a weight reduction of 7.7% and 8.9% of initial weight for folic acid supplementation and placebo groups, respectively. Serum folate concentrations increased for 3 folds (p < 0.001) in the folic acid group. In the folic acid group, there was a trend of lower fasting serum homocysteine concentrations (7.6 +/- 0.2 vs. 7.3 +/- 0.3 micromol/L), but it did not reach statistical significance (p = 0.170). However, we found that serum homocysteine concentrations decreased significantly in those with higher baseline homocysteine concentrations (8.7 +/- 1.3 vs. 7.8 +/- 1.5 micromol/L, p = 0.004), while it did not change in those with lower baseline homocysteine concentrations (6.6 +/- 0.6 vs. 6.8 +/- 1.2 micromol/L, p = 0.334). Reduction of serum homocysteine concentrations did not correlate with elevation of serum folate concentrations (p = 0.646) in obese women with higher baseline homocysteine concentrations. In conclusion, serum homocysteine concentrations can be maintained in obese women during mild to moderate weight loss. Folic acid supplementation decreased serum homocysteine concentrations in those women who had higher serum homocysteine concentrations before participating in the weight reduction program.     

Effect of low birth weight on adrenal steroids and carbohydrate metabolism in early adulthood

AIM: Data are inconsistent whether hyperinsulinemia might be associated with adrenal hyperandrogenism in young adults born with low birth weight (LBW). METHOD: We investigated the insulin and adrenal steroid production of 70 young LBW adults [33 women (birth weight: 1,795 +/- 435 g) and 37 men (birth weight: 1,832 +/- 337 g)]. Their results were compared to those of 30 controls (14 men, 16 women), born with normal weight. RESULTS: In LBW women, we measured higher basal DHEA (33.5 +/- 13.1 vs. 23.6 +/- 8.7 nmol/l, p < 0.05), DHEAS (8.0 +/- 2.3 vs. 6.3 +/- 2.1 micromol/l, p < 0.05), androstenedione (8.3 +/- 2.8 vs. 6.0 +/- 2.2 nmol/l, p < 0.05) and cortisol (0.25 +/- 0.07 vs. 0.20 +/- 0.07 micromol/l, p < 0.05) levels and higher insulin response during oral glucose tolerance test (log.AUCins: 2.62 +/- 0.06 vs. 2.57 +/- 0.03, p < 0.05). DHEA levels correlated with fasting insulin levels (r = 0.45, p < 0.01) and insulin response (r = 0.33, p < 0.05). In LBW men, higher cortisol (0.27 +/- 0.06 vs. 0.22 +/- 0.06 micromol/l, p < 0.01) and SHBG (18.4 +/- 10.4 vs. 12.7 +/- 5.9 nmol/l, p < 0.05) levels were found. CONCLUSIONS: Our results suggest that modest hypercortisolism is present in young LBW adults. While the endocrine sequel of hypercortisolism raised insulin response and hyperandrogenism is detectable in apparently healthy young LBW women, it is absent in young LBW men. This suggests that gender-dependent mechanisms might play a role in the development of insulin resistance in LBW adults.     

Vitamin E modulation of C-reactive protein in smokers with acute coronary syndromes

Acute coronary syndromes are characterized by the expression of proinflammatory cytokines such as C-reactive protein (CRP). Sustained upregulation of inflammatory markers is associated with an adverse prognosis. Vitamin E is known to have significant anti-inflammatory properties and has been associated with a reduction in cardiovascular events in some studies of high-risk patients. The mechanism of benefit remains controversial. We conducted a randomized, double-blind placebo controlled trial of vitamin E 400 IU daily for 6 months in 110 patients with acute coronary syndromes. Serum samples were collected at enrollment and at 2, 4, and 6 months. CRP, interleukin-6 and the soluble cell adhesion molecules were measured. Vitamin E levels increased significantly in the treatment group (from 31 micromol/l at baseline to 51 micromol/l, p <.0001) and were unchanged in the placebo group (32 micromol/l at baseline to 34 micromol/l, p = NS). CRP levels fell in both the vitamin E group and the placebo group over the treatment period (from 17.2 +/- 2.9 to 6.1 +/- 0.8 mg/l and from 21.5 +/- 4.9 to 5.9 +/- 0.9 mg/l, p = NS for the difference between active and placebo groups). However, vitamin E treatment was associated with significantly lower 6 month CRP levels in smokers versus smokers on placebo (4.7 +/- 0.71 mg/l vs. 8.26 +/- 1.5 mg/l, p =.02). Vitamin E reduces CRP levels in smokers with acute coronary syndromes for up to 6 months after hospitalization.     

Hyperlipoproteinemia impairs endothelium-dependent vasodilation

Atherogenic lipoproteins can cause endothelial dysfunction in the initial stage of atherogenesis. In our study we examined 134 patients with defined hyperlipoproteinemia (non-HDL cholesterol>4.1 mmol/l or triglycerides>2.5 mmol/l or taking any of lipid lowering drugs)--94 men and 40 women. The subgroup of controls of comparable age contained 54 normolipidemic individuals--30 men and 24 women. Patients with hyperlipoproteinemia revealed significantly lower ability of endothelium-dependent flow-mediated vasodilation (EDV) measured on brachial artery (4.13+/-3.07 vs. 5.41+/-3.82 %; p=0.032) and higher carotid intima media thickness than normolipidemic controls (0.68+/-0.22 vs. 0.58+/-0.15 mm; p=0.005). In regression analysis, EDV correlated significantly with plasma concentrations of oxLDL (p<0.05) HDL-cholesterol (p<0.05), Apo A1 (p<0.05), ATI (p<0.01) and non-HDL cholesterol (p<0.05). Patients with hyperlipoproteinemia showed higher plasma levels of oxLDL (65.77+/-9.54 vs. 56.49+/-7.80 U/l; p=0.015), malondialdehyde (0.89+/-0.09 vs. 0.73+/-0.08 micromol/l; p=0.010) and nitrites/nitrates (20.42+/-4.88 vs. 16.37+/-4.44 micromol/l; p=0.018) indicating possible higher long-term oxidative stress in these patients.     

VLDL-triglyceride kinetics during hyperglycemia-hyperinsulinemia: effects of sex and obesity

We have previously shown that sex and obesity independently affect basal very low density lipoprotein (VLDL)-triglyceride (TG) kinetics. In the present study, we investigated the effect of hyperglycemia-hyperinsulinemia on VLDL-TG kinetics in lean and obese men and women (n = 6 in each group). VLDL-TG kinetics were measured during basal, postabsorptive conditions and during glucose infusion (5.5 mg x kg FFM(-1) x min(-1)) by using [(2)H(5)]glycerol bolus injection in conjunction with compartmental modeling analysis. Basal VLDL-TG secretion in plasma was greater in obese than in lean men (7.8 +/- 0.6 and 2.9 +/- 0.4 micromol x l plasma(-1) x min(-1); P < 0.001) but was not different in lean and obese women (5.0 +/- 1.1 and 5.9 +/- 1.1 micromol x l plasma(-1) x min(-1)). Glucose infusion decreased the VLDL-TG secretion rate by approximately 50% in lean and obese men and in lean women (to 1.5 +/- 0.4, 4.0 +/- 0.6, and 2.2 +/- 0.4 micromol x l plasma(-1) x min(-1), respectively; all P < 0.05) but had no effect on the VLDL-TG secretion rate in obese women (4.9 +/- 1.0 micromol x l plasma(-1) x min(-1)). These results demonstrate that both sex and adiposity affect the regulation of VLDL-TG metabolism. Glucose and insulin decrease VLDL-TG production in both lean men and lean women; obesity is associated with resistance to the glucose- and insulin-mediated suppression of VLDL-TG secretion in women, but not in men.     

Gene-nutrient and gene-gene interactions of controlled folate intake by Japanese women

Elevated serum total homocysteine (tHcy) levels are associated with increased risk for cardiovascular disease and dementia. The prevalence rates of homozygous mutants among Japanese women (n = 300) were 17.3%, 1.3%, 18.6%, and 5.3% for methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, reduced folate carrier (RFC-1) A80G, and methionine synthase (MS) A2756G, respectively. The tHcy value was significantly lower (p < 0.001) in young women with CC or CT of MTHFR than with TT (10.9+/-4.7 micromol/L) (n =250). Diversities of serum folate and tHcy in women with 23 combinations of different alleles at low folate intake converged to the highest (34.0+/-8.6 nmol/L) and lowest (7.6+/-1.5 micromol/L) levels, respectively, after folic acid (400 microg/day) supplementation. In the regression equation ( y= ax + b) of serum folate ( y nmol/L) plotted against mean folate intake ( x microg/day), the values of "a" were 0.032, 0.037, and 0.045 for individuals with CC, CT, and TT alleles, respectively, of MTHFR.     

Homocysteine levels in acromegaly patients

Acromegaly is associated with a two to three-fold increase in mortality related predominantly to cardiovascular disease. The excess mortality is associated most closely with higher levels of growth hormone (GH). Survival in acromegaly may be normalized to a control age-matched rate by controlling GH levels; in particular, GH levels less than 2.5 ng/mL are associated with survival rates equal to those of the general population. Hyperhomocysteinemia has also been recognized as a risk factor for cardiovascular disease, yet there are limited data on the prevalence of hyperhomocysteinemia in patients with acromegaly. Eighteen acromegaly patients (7 male, 11 female, mean age 42.8 +/- 11.0 years) in our endocrine clinic consented to having the following tests performed: complete blood count (CBC), thyroid hormones, folic acid, vitamin B12, plasma homocysteine levels, uric acid, fibrinogen, CRP, fasting glucose, insulin, C-peptide, total serum cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, GH, insulin-like growth factor-1 (IGF-1) and GH levels after an oral glucose tolerance test (OGTT). By history, fourteen had macroadenomas and four had microadenomas; eight had hypertension; two had glucose intolerance, and four had diabetes. Fifteen had had transsphenoidal or transfrontal surgery: two had been cured, but 13 others were taking long-acting octreotide. Five patients had undergone radiotherapy and the acromegaly in two was treated primarily with long-acting octreotide. CBC, thyroid hormone, folic acid, and vit B12 levels were normal in all patients. We divided the patients into two groups according to mean GH levels after an OGTT: Group 1 (GH<2.5 ng/mL, n=10), and Group 2 (GH<2.5 ng/mL, n=8). Comparison of the two groups using Mann-Whitney U testing revealed statistically significant lower levels in Group 1 of the following parameters: GH (1.91 +/- 0.90 vs. 8.58 +/- 5.55 ng/mL, p=0.002), IGF-1 (338.30 +/- 217.90 vs. 509.60 +/- 293.58 ng/dL, p=0.06), GH after an OGTT (1.42 +/- 0.81 vs. 9.01 +/- 4.53 ng/mL, p=0.001), plasma homocysteine (12.85 +/- 4.47 vs. 18.20 +/- 4.99 micromol/L, p=0.05), total cholesterol (164.0 +/- 20.81 vs. 188.0 +/- 22.26 mg/dL, p=0.05) and LDL cholesterol (81.0 +/- 9.64 vs. 116.70 +/- 13.03 mg/dl, p=0.01). Differences between the other parameters were not significantly different. Acromegaly patients with high GH levels after an OGTT have much higher levels of homocysteine than patients with lower GH levels. The role of elevated homocysteine levels as an independent cardiovascular risk factor in the mortality of acromegaly patients should be determined in future studies.     

C677T mutation of methylenetetrahydrofolate reductase gene and serum homocysteine levels in Turkish patients with coronary artery disease

Elevated levels of homocysteine is a risk factor for coronary artery disease. The C677T transition in methylenetetrahydrofolate reductase (MTHFR) is associated with increased homocysteine levels in the general population. We analysed the association between the MTHFR C677T polymorphism and serum homocysteine concentrations in patients with coronary artery disease (CAD). Allele frequencies for the 'C' (wild-type) and 'T' alleles were 0.71 and 0.29 in CAD patients and 0.70 and 0.30 in controls, respectively. There was no difference in the distribution of MTHFR genotypes between patients with CAD and control subjects (p > 0.05). In the patient group, homocysteine levels were higher than controls but not significantly (13.99 +/- 7.44 vs. 11.77 +/- 5.18 micromol l(-1); p > 0.05). Serum homocysteine concentration was significantly higher in the TT genotype with respect to CC and CT genotypes in both the control group (p < 0.01) and patient group (p < 0.01). Systolic and diastolic blood pressures in subjects with different MTHFR genotypes did not differ significantly. In conclusion, MTHFR C677T mutation was significantly related to hyperhomocysteinemia. In spite of the clear effect of the MTHFR polymorphism on elevated homocysteine levels, we did not observe any associations among the MTHFR genotypes with a the risk of CAD in the Turkish population.     

Ascorbic acid does not affect large elastic artery compliance or central blood pressure in young and older men

Large elastic artery compliance is reduced and arterial blood pressure (BP) is increased in the central (cardiothoracic) circulation with aging. Reactive oxygen species may tonically modulate central arterial compliance and BP in humans, and oxidative stress may contribute to adverse changes with aging. If so, antioxidant administration may have beneficial effects. Young (Y; 26 +/- 1 yr, mean +/- SE) and older (O; 63 +/- 2 yr, mean +/- SE) healthy men were studied at baseline and during acute (intravenous infusion; Y: n = 13, O: n = 12) and chronic (500 mg/day for 30 days; Y: n = 10, O: n = 10) administration of ascorbic acid (vitamin C). At baseline, peripheral (brachial artery) BP did not differ in the two groups, but carotid artery compliance was 43% lower (1.2 +/- 0.1 vs. 2.1 +/- 0.1 mm(2)/mmHg x 10(-1), P < 0.01) and central (carotid) BP (systolic: 116 +/- 5 vs. 101 +/- 3 mmHg, P < 0.05, and pulse pressure: 43 +/- 4 vs. 36 +/- 3 mmHg, P = 0.16), carotid augmentation index (AIx; 27.8 +/- 7.8 vs. -20.0 +/- 6.6%, P < 0.001), and aortic pulse wave velocity (PWV; 950 +/- 88 vs. 640 +/- 38 cm/s, P < 0.01) were higher in the older men. Plasma ascorbic acid concentrations did not differ at baseline (Y: 71 +/- 5 vs. O: 61 +/- 7 micromol/l, P = 0.23), increased (P < 0.001) to supraphysiological levels during infusion (Y: 1240 +/- 57 and O: 1,056 +/- 83 micromol/l), and were slightly elevated (P < 0.001 vs. baseline) with supplementation (Y: 96 +/- 5 micromol/l vs. O: 85 +/- 6). Neither ascorbic acid infusion nor supplementation affected peripheral BP, heart rate, carotid artery compliance, central BP, carotid AIx, or aortic PWV (all P > 0.26). These results indicate that the adverse changes in large elastic artery compliance and central BP with aging in healthy men are not 1). mediated by ascorbic acid-sensitive oxidative stress (infusion experiments) and 2). affected by short-term, moderate daily ascorbic acid (vitamin C) supplementation.     

Correlation between serum alkaline phosphatase activity and blood glucose levels

Fasting blood glucose levels and serum alkaline phosphatase activity of age-matched Libyan diabetic men (168) and women (168) were determined. The mean levels of blood glucose of men and women were 227 +/- 6 and 237 +/- 5 mg/dl, respectively. The respective values of serum alkaline phosphatase were 179 +/- 5 and 199 +/- 6 IU/l. The mean serum phosphatase activity of women was significantly higher (p less than 0.001) than that of their male counterparts. A statistically significant positive correlation was found between serum alkaline phosphatase and blood glucose levels of these diabetic patients (r = 0.35; p less than 0.001).     

Serum nitric oxide metabolite levels in a general healthy population: relation to sex and age

This study aims at determining serum nitrite/nitrate (NO(x)) levels in healthy subjects within the framework of a population-based study. NO(x) concentration was measured in 3505 subjects aged >/=20 years. Subjects with diabetes, renal dysfunction, those undergoing treatment for dyslipidemia and hypertension, were excluded; also excluded were smokers, pregnant women, and subjects with cardiovascular and infectious diseases or cancer; leaving 1983 (667 men, 1316 women) asymptomatic non-smoking subjects for the analysis. NO(x) concentrations were determined in serum and compared in different age groups. Mean+/-SE of NO(x) concentration was 24.8+/-0.02 and 24.4+/-0.01 micromol/l in men and women respectively. Men aged 20-29 years had significantly higher NO(x) levels compared to corresponding women (25.1+/-0.03 vs. 22.7+/-0.02). Serum NO(x) concentration peaked at 50-59 years in both genders. Comparison between lower and upper quartiles of NO(x) levels was performed in both genders. Women with high serum NO(x) were older and had significantly higher body mass index and fasting plasma glucose. The results of this study determine the normal levels of serum NO(x) concentrations in asymptomatic non-smoker subjects; also show that serum NO(x) concentrations indicate sex and age differences in these subjects.     

Differences in plasma homocysteine levels between Zucker fatty and Zucker diabetic fatty rats following 3 weeks oral administration of organic vanadium compounds

PURPOSE: Recently, our laboratory group has reported that rats with Type 1 diabetes have decreased plasma homocysteine and cysteine levels compared to non-diabetic controls and that organic vanadium treatment increased plasma homocysteine concentrations to non-diabetic concentrations. However, to date, no studies have been done investigating the effects of organic vanadium compounds on plasma homocysteine and its metabolites in Type 2 diabetic animal model. These studies examined the effect of organic vanadium compounds [bis(maltolato)oxovanadium(IV) and bis(ethylmaltolato)oxovanadium(IV); BMOV and BEOV] administered orally on plasma concentrations of homocysteine and its metabolites (cysteine and cysteinylglycine) in lean, Zucker fatty (ZF) and Zucker diabetic fatty (ZDF) rats. ZF rats are a model of pre-diabetic Type 2 diabetes characterized by hyperinsulinemia and normoglycemia. The ZDF rat is a model of Type 2 diabetes characterized by relative hypoinsulinemia and hyperglycemia. METHODS: Zucker lean and ZF rats received BMOV in the drinking water at a dose of 0.19 +/- 0.02 mmol/kg/day. Lean and ZDF rats received BEOV by oral gavage daily at dose of 0.1 mmol/kg. The treatment period for both studies was 21 days. At termination, animals were fasted overnight (approximately 16 h) and blood samples were collected by cardiac puncture for determination of plasma glucose, insulin and homocysteine levels. Plasma homocysteine and its metabolites levels were determined using high-pressure liquid chromatography. Plasma glucose was determined using a Glucose Analyzer 2. Plasma insulin levels were determined by radioimmunoassay. Plasma triglycerides were determined by an enzymatic assay methodology. RESULTS: ZF (n = 4) and ZDF (n = 10) rats had significantly lower plasma homocysteine as compared to their respective lean groups (ZF 0.78 +/- 0.1 micromol/L vs. Zucker lean 2.19 +/- 0.7 micromol/L; ZDF 1.71 +/- 0.2 micromol/L vs. Zucker lean 3.02 +/- 0.3 micromol/L; p < 0.05). BMOV treatment in ZF rats restored plasma homocysteine levels to those observed in lean untreated rats (ZF treated: 2.04 +/- 0.2 micromol/L; lean 2.19 +/- 0.7 micromol/L). There was a modest effect of BMOV treatment on plasma glucose levels in ZF rats. BEOV treatment significantly decreased the elevated plasma glucose levels in the ZDF rats (lean 7.9 +/- 0.1 mmol/L; lean + vanadium 7.7 +/- 0.2 mmol/L; ZDF 29.9 +/- 0.4 mmol/L; ZDF + vanadium 17.4 +/- 0.3 mmol/L, p < 0.05). Organic vanadium treatment reduced cysteine levels in both ZF and ZDF rats. No differences in total plasma cysteinylglycine concentrations were observed. CONCLUSION: Plasma homocysteine levels are significantly reduced in a pre-diabetic model of Type 2 diabetes, which was restored to lean levels upon vanadium treatment; however, this restoration of plasma homocysteine levels was not seen in ZDF Type 2 diabetic rats following vanadium treatment. In the latter case vanadium treatment may not have totally overcome the insulin resistance seen in these animals.     

The effects of hydrogen peroxide promoted by homocysteine and inherited catalase deficiency on human hypocatalasemic patients

Elevated plasma homocysteine can generate oxygen free radicals and hydrogen peroxide. The enzyme catalase is involved in the protection against hydrogen peroxide. We examined the effect of oxidative stress promoted by homocysteine on erythrocyte metabolism (blood hemoglobin, MCV, folate, B12, serum LDH, LDH isoenzymes, haptoglobin) in the oxidative stress sensitive Hungarian patients with inherited catalase deficiency. The plasma homocysteine (HPLC method, Bio-Rad), folate, B12 (capture binding assay, Abbott), blood hemoglobin concentrations, blood catalase activity (spectrophotometric assay of hydrogen peroxide), and MCV values were determined in 7 hypocatalasemic families including hypocatalasemic (male:12, female:18) patients and their results were compared to those of the normocatalasemic (male:17 female: 12) family members. We found decreased (p <.036) folate (ng/ml) concentrations (male hypocatalasemic 5.44 +/- 2.81 vs. normocatalasemic 7.56 +/- 1.97, female 5.01 +/- 1.93 vs. 6.61 +/- 1.91), blood hemoglobin (p <.010, male:140.2 +/- 11.0 vs. 153.6 +/- 11.6 g/l, female: 128.4 +/- 10.9 vs. 139.6 +/- 9.2 g/l). Increased levels of MCV (p <.001) were detected in hypocatalasemic patients (male: 98.6 +/- 3.4 vs. 90.1 +/- 7.5 fl, female: 95.9 +/- 3.9 vs. 90.1 +/- 2.5 fl), plasma homocysteine (p <.049, male: 9.72 +/- 3.61 vs. 7.36 +/- 2.10 umol/l, female: 9.06 +/- 3.10 vs. 6.84 +/- 2.50 umol/l) and not significant (p >.401) plasma B12 (male: 336 +/- 108 vs. 307 +/- 76 pg/ml, female: 373 +/- 180 vs. 342 +/- 75 pg/ml). The serum markers of hemolysis (LDH, LDH isoenzymes, haptoglobin) did not show significant (p >.228) signs of oxidative erythrocyte damage. We report firstly on increased plasma homocysteine concentrations in inherited catalase deficiency. The increased plasma homocysteine and inherited catalase deficiency together could promote oxidative stress via hydrogen peroxide. The patients with inherited catalase deficiency are more sensitive to oxidative stress of hydrogen peroxide than the normocatalasemic family members. This oxidative stress might be responsible for the decreased concentration of the blood hemoglobin via the oxidation sensitive folate and may contribute to the early development of arteriosclerosis and diabetes in these patients.     

Leg free fatty acid kinetics during exercise in men and women

We previously reported that epinephrine stimulates leg free fatty acid (FFA) release in men but not in women. The present studies were conducted to determine whether the same is true during exercise. Six men and six women bicycled for 90 min at 45% of peak O(2) consumption, during which time systemic and leg FFA kinetics ([9, 10-(3)H]palmitate) were measured. The catecholamine and hormonal responses to exercise were not different in men and women. The baseline systemic and leg palmitate release was 94 +/- 15 vs. 114 +/- 5 micromol/min and 16 +/- 2 and 20 +/- 3 micromol/min, respectively, in men and women [P = nonsignificant (NS)]. Systemic and leg palmitate release increased (both P < 0.001) to 251 +/- 18 vs. 212 +/- 16 micromol/min and 73 +/- 19 vs. 80 +/- 12 micromol/min in men and women, respectively, during the last 30 min of exercise (P = NS, men vs. women). We conclude that the systemic and leg adipose tissue lipolytic response to exercise is not different in nonobese men and women.     

Plasma C-reactive protein is not elevated in physically active postmenopausal women taking hormone replacement therapy.

We tested the hypothesis that hormone replacement therapy (HRT)-related increases in C-reactive protein (CRP) would either be blunted or absent in postmenopausal women who regularly perform endurance exercise. Plasma CRP is an independent predictor of future cardiovascular events in healthy men and women. Oral HRT increases plasma CRP concentrations in postmenopausal women. Regular aerobic exercise reduces the risk of cardiovascular events and is associated with lower CRP concentrations in adults. To date, no study has evaluated the influence of habitual physical activity on the elevation of CRP associated with HRT. Plasma CRP concentrations were measured in 114 postmenopausal women: 39 physically active (endurance trained) and 75 sedentary postmenopausal subjects. Sixty-five women were users of HRT (22 physically active and 43 sedentary), and 49 were nonusers (17 physically active and 32 sedentary). CRP levels were approximately 75% higher (P < 0.01) in the sedentary users vs. nonusers of HRT (1.9 +/- 1.8 vs. 1.1 +/- 1.0 mg/l). In contrast, there was no difference in CRP levels between the physically active users and nonusers of HRT (0.6 +/- 0.4 vs. 0.4 +/- 0.2 mg/l; P = 0.61). Regardless of HRT status, CRP concentrations were approximately 65% lower in the physically active compared with sedentary women. In conclusion, physically active postmenopausal women exhibit lower plasma CRP concentrations compared with sedentary controls. Importantly, the HRT-related elevation in plasma CRP levels observed in sedentary women is absent in women who engage in regular endurance exercise. These data suggest that habitual physical activity may prevent the elevation in CRP concentrations due to HRT.     

Effect of diet and 677 C-->T 5, 10-methylenetetrahydrofolate reductase genotypes on plasma homocyst(e)ine concentrations in slovak adolescent population

The objective of this study was to evaluate the effect of diet and 677 C-->T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene on plasma homocyst(e)ine concentrations in an adolescent population (113 males, age: 14.2+/-2.4 years; 202 females, age: 14.9+/-2.1 years) from a region characterized by high cardiovascular mortality. Homocyst(e)ine levels did not differ between males and females (9.4+/-3.5 and 8.9+/-3.1 micromol/l, respectively). The homozygosity for the 677 C-->T MTHFR mutation was found in 4.6 % of subjects. No differences in homocyst(e)ine levels were found between MTHFR genotypes. Analysis of the diet composition which was performed on a 24-hour daily recall basis and a food frequency questionnaire showed a low daily intake of vitamin B6 (males: 1.13 mg/66% RDA; females: 0.92 mg/61% RDA). Daily folic acid intake was 0.21 g/105% RDA in males and 0.23 g/115% RDA in females. The results of our study show that the high homocyst(e)ine levels in the adolescent population were not affected by the 677 C-->T MTHFR mutation. We conclude that an insufficient dietary intake of vitamin B6 and folic acid is responsible for this finding. This is in accord with the recommendation that the dietary allowances for folate should be reset to the originally prescribed levels of 0.4 g/day which should be sufficient to control the homocysteine levels.     

Serum levels of TNF-alpha,sIL-2R,IL-6, and IL-8 are increased and associated with elevated lipid peroxidation in patients with Behçet's disease

AIM: Behçet''s disease (BD) is asystemic immunoinflammatory disorder and the aetiopathogenesis is to be specified. Cytokines play a role in immune response and in many inflammatory diseases. The aim of this case-control study is to investigate serum pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha, interleukin-1beta (IL-1beta), soluble IL-2 receptor (sIL-2R), IL-6, and chemokine IL-8 levels in patients with BD. We also determined the end product of lipid peroxidation (malondialdehyde (MDA)) in BD patients as an index for oxidative stress. METHODS: A total of 37 patients (19 men, 18 women) with BD (active, n = 17; inactive, n = 20) and 20 age-matched and sex-matched healthy control subjects (11 men, nine women) included in this cross-sectional, blinded study. Serum TNF-alpha, IL-1beta, sIL-2R, IL-6 and IL-8 levels were determined by a spectrophotometer technique using the immulite chemiluminescent immunometric assay. Lipid peroxidation was evaluated by Wasowicz et aL The levels of cytokines and lipid peroxidation in the active period were compared with the inactive period of the disease. Results are expressed as mean +/- standard error. RESULTS: IL-1beta levels were below the detection limits of the assay (< 5 pg/ml) in all samples. Mean levels of MDA (8.1+/-0.7 micromol/l), sIL-2R (800+/-38 U/ml), IL-6 (12.6+/-1.1 pg/ml), IL-8 (7.2+/-0.4 pg/ml), and TNF-alpha (7.9+/-0.5 pg/ml) in active BD patients were significantly higher than those in inactive patients (4.3+/-0.5 micromol/l, p < 0.01; 447+/-16 U/ml, p < 0.001; 8.3+/-0.6 pg/ml, p = 0.006; 5.3+/-0.1 pg/ml, p < 0.001; and 5.1 0.2 pg/ml, p < 0.001; respectively) or control subjects (2.1+/-0.2 micromol/l, p < 0.001; 446+/-20 U/ml, p < 0.001; 6.4+/-0.2 pg/ml, p < 0.001; 5.4+/-0.1 pg/ml, p < 0.001; and 4.7+/-0.1 pg/ml, p < 0.001, respectively). On the contrary, only the mean IL-6 level was significantly different between inactive BD and control subjects (p = 0.02). All acute phase reactants were significantly higher in active BD than in inactive period (for each, p < 0.01). Conclusions: High levels of sIL-2R, IL-6, IL-8 and TNF-alpha indicate the activation of immune system in BD. Serum sIL-2R, IL-6, IL-8 and TNF-alpha seem to be related to disease activity. Increased lipid peroxidation suggests oxidative stress in BD and therefore tissue damage in such patients. Amelioration of clinical manifestations would be envisaged by targeting these cytokines, chemokines and lipid peroxidation with pharmacological agents.