Creatine supplementation prevents hyperhomocysteinemia, oxidative stress and cancer-induced cachexia progression in Walker-256 tumor-bearing rats.

The purpose of this study was to investigate (1) the impact of tumor growth on homocysteine (Hcy) metabolism, liver oxidative stress and cancer cachexia and, (2) the potential benefits of creatine supplementation in Walker-256 tumor-bearing rats. Three experiments were conducted. First, rats were killed on days 5 (D5), 10 (D10) and 14 (D14) after tumor implantation. In experiment 2, rats were randomly assigned to three groups designated as control (C), tumor-bearing (T) and tumor-bearing supplemented with creatine (TCr). A life span experiment was conducted as the third experiment. Creatine was supplied in drinking water for 21 days (8 g/L) in all cases. Tumor implantation consisted of a suspension of Walker-256 cells (8.0 × 10(7) cells in 0.5 mL of PBS). The progressive increase (P < 0.05) in tumor mass coincided with a progressively lower body weight and higher hepatic oxidative stress; plasma Hcy concentration was 80 % higher (P < 0.05) by 10 days of tumor implantation. Impaired Hcy metabolism was evidenced by decreased hepatic betaine-homocysteine methyltransferase (Bhmt), glycine N-methyltransferase (Gnmt) and cystathionine beta synthase (CBS) gene expression. In contrast, creatine supplementation promoted a 28 % reduction of tumor weight (P < 0.05). Plasma Hcy (C 6.1 ± 0.6, T 10.3 ± 1.5, TCr 6.3 ± 0.9, µmol/L) and hepatic oxidative stress were lower in the TCr group compared to T. Creatine supplementation was unable to decrease Hcy concentration and to increase SAM/SAH ratio in tumor tissue. These data suggest that creatine effects on hepatic impaired Hcy metabolism promoted by tumor cell inoculation are responsible to decrease plasma Hcy in tumor-bearing rats. In conclusion, Walker-256 tumor growth is associated with progressive hyperhomocysteinemia, body weight loss and liver oxidative stress in rats. Creatine supplementation, however, prevented these tumor-associated perturbations.

Folic acid and autism: What do we know?

Autism spectrum disorders (ASD) consist in a range of neurodevelopmental conditions that share common features with autism, such as impairments in communication and social interaction, repetitive behaviors, stereotypies, and a limited repertoire of interests and activities. Some studies have reported that folic acid supplementation could be associated with a higher incidence of autism, and therefore, we aimed to conduct a systematic review of studies involving relationships between this molecule and ASD. The MEDLINE database was searched for studies written in English which evaluated the relationship between autism and folate. The initial search yielded 60 potentially relevant articles, of which 11 met the inclusion criteria. The agreement between reviewers was κ = 0.808. The articles included in the present study addressed topics related to the prescription of vitamins, the association between folic acid intake/supplementation during pregnancy and the incidence of autism, food intake, and/or nutrient supplementation in children/adolescents with autism, the evaluation of serum nutrient levels, and nutritional interventions targeting ASD. Regarding our main issue, namely the effect of folic acid supplementation, especially in pregnancy, the few and contradictory studies present inconsistent conclusions. Epidemiological associations are not reproduced in most of the other types of studies. Although some studies have reported lower folate levels in patients with ASD, the effects of folate-enhancing interventions on the clinical symptoms have yet to be confirmed.

Whey protein supplementation increases methionine intake but not homocysteine plasma concentration in rats.

The purpose of this study was to examine the effects of whey protein supplementation on homocysteine (Hcy) metabolism and liver oxidative stress in rats. Twenty-four rats were divided into 3 groups (n = 8) to receive one of the following diets for 4 weeks: control diet (C), whey protein-composed diet (WP), and whey protein-supplemented diet (WPS). The C and WP diets consisted of AIN-93 with 20% casein and 20% whey protein as protein source, respectively. WPS was AIN-93 (20% casein) supplemented by the addition of 20% (w/w) whey protein. Four weeks of ingesting a WPS diet resulted in a significantly higher (P < 0.05) total protein and methionine intakes. Although a significant increase (P < 0.05) in the hepatic S-adenosylmethionine and S-adenosylhomocysteine levels occurred in WPS group compared with C and WP, no significant change was observed in plasma Hcy concentration between groups. Furthermore, the levels of lipid hydroperoxides and advanced oxidation protein products, known liver oxidative stress markers, were increased in the WPS group compared with the C group. In addition, no change in glutathione liver concentration was observed in any of the groups studied. In conclusion, whey protein supplementation increases methionine intake substantially; however, it does not change plasma Hcy concentrations. On the other hand, increased hepatic oxidative stress markers were observed in whey protein supplemented rats were probably due to high protein intake.

Effect of folate, vitamin B6, and vitamin B12 intake and MTHFR C677T polymorphism on homocysteine concentrations of renal transplant recipients.

Plasma hyperhomocysteinemia (HHcy) is considered a risk factor for chronic allograft dysfunction (CAD), the main cause of functional loss in transplant recipients. Genetic polymorphisms that alter enzymes involved in homocysteine (Hcy) metabolism, such as methylenetetrahydrofolate reductase (MTHFR), and vitamin deficiency can result in HHcy. The objectives of this study were to investigate the relationship between HHcy and CAD development, and to evaluate the effect of intake of folate and vitamins B6 and B12 as well as MTHFR C677T polymorphism on Hcy concentrations. Ninety-eight renal transplant recipients including 48 showing CAD and 50 with normal renal function (NRF), were included in this cross-sectional study. Peripheral blood samples were collected for plasma Hcy quantification by liquid chromatography/sequential mass spectrometry (LC-MS/MS), and for MTHFR polymorphism analysis using polymerase chain reaction-restriction fragment length polymorphism. Dietary intake was evaluated using a nutritional questionnaire. HHcy (P=.002) and higher mean concentrations of Hcy (P=.029) were associated with CAD. An association was observed between HHcy and 677T variant allele in the CAD group (P=.0005). There was no correlation between Hcy concentration and folate, vitamin B6 or vitamin B12 intake in the CAD group. However, a negative correlation was observed between Hcy concentration and folate intake (P=.043), and also between Hcy concentration and vitamin B6 intake (P=.030) in the NRF group. According to our study, HHcy is associated with CAD development. In patients with CAD, MTHFR polymorphism seems to have a greater effect on the Hcy concentration than the vitamin intake. Increased folate and vitamin B6 intakes seem to reduce Hcy concentrations among transplant recipients with NRF, and could contribute to reducing the risk of CAD development.

Concurrent folate treatment prevents Na+,K+-ATPase activity inhibition and memory impairments caused by chronic hyperhomocysteinemia during rat development.

We investigated the hypothesis that folate administration would prevent hyperhomocysteinemia-induced memory deficits and Na(+),K(+)-ATPase activity inhibition. Chronic hyperhomocysteinemia was induced from the 6th to the 28th day of life by subcutaneous injection of homocysteine (0.3-0.6 micromol/g), twice a day; control Wistar rats received the same volume of saline solution (0.9% NaCl). Half of the homocysteine- and saline-treated groups also received intraperitoneal administration of folate (0.011 micromol/g) from the 6th to the 28th day of life. A group of animals was killed 12 h after the last injection, plasma and parietal cortex were collected for biochemical analysis. Another group stayed at Central Animal House until 60th day of life, when the rats were submitted to behavioral testing in water maze or were killed for evaluation of cortical Na(+),K(+)-ATPase activity. Results showed that hyperhomocysteinemia impaired reference memory for platform location, as assessed by fewer crossings to the platform place and increased latency for the first crossing, when compared to controls. In the working memory task homocysteine-treated animals also needed more time to find the platform. We also observed that Na(+),K(+)-ATPase activity was reduced in parietal cortex of hyperhomocysteinemic rats sacrificed 12h after the last injection of homocysteine (29-day-old rats). In contrast, this enzyme was not altered when the rats were sacrificed 31 days after the treatment (60-day-old rats). Hyperhomocysteinemic rats treated with folate had all those impairments prevented, an effect probably related to folate antioxidant properties.

Effect of oral hormone replacement therapy on plasma homocysteine levels.

BACKGROUND: Various inherited or acquired conditions can lead to mild or severe hyperhomocysteinemia, which has toxic effects on the vascular endothelium. It has been reported that hormone replacement therapy is associated with decreased homocysteine plasma levels, but this is still a controversial issue. PURPOSE: To compare homocysteine plasma levels in women before and after 3 months of oral hormone replacement therapy. METHODS: Twenty-four women were selected to take part in the study. Blood samples were collected immediately before hormone replacement therapy (cyclic association of 2 mg of estradiol valerate and 1 mg of cyproterone acetate) and three months after the beginning of hormone replacement therapy. Samples collected before hormone replacement therapy were used as controls. Plasma homocysteine levels and the presence of C677T mutation in the methylene tetrahydrofolate reductase gene were evaluated in all participants. RESULTS: The methylene tetrahydrofolate reductase gene mutation was detected in 8 women (33.3%) in heterozygosis, in 3 (12.5%) in homozygosis, and 13 women (54.2%) did not present the mutation. No significant differences were observed in homocysteine levels before and after three months of oral hormone replacement therapy, regardless of the C677T genotype. CONCLUSIONS: The results obtained indicate that homocysteine plasma levels are not affected after three months of oral hormone replacement therapy.

[Plasma homocysteine concentration and its relationship with the development of preeclampsia. Effect of prenatal administration of folic acid]. / Concentraciones de homocisteína plasmática en embarazadas y su relación con el desarrollo de preeclampsia. Efecto de la administración prenatal de ácido fólico.

The increase of plasmatic homocysteine (Hc) in pregnant women, who later develop preeclampsia/eclampsia, the cause of this increment and its pathogenic role in toxemia of pregnancy, are still controversial. The objectives of the present research were to determine the plasmatic He concentrations during the first and second trimesters of pregnancy and the effect of folic acid administration on these values, and in the prevention of preeclampsia. Ninety six pregnant women of low economic background were studied on the first prenatal consultation: 27 women in the first trimester of pregnancy and 59 in the second. After 8 hours of fasting, venous blood was extracted and each patient was provided with 1 mg folic acid tablets and instructed to ingest one tablet daily, and to come back to the laboratory after three months. Plasma homocysteine and serum folic acid were determined for each patient before and after the folic acid treatment, by using the IMX system (Abbott Lab) and radioimmunoassay, respectively. Basal homocysteine concentrations were 4.0 +/- 2.1 micromol/L and 4.8 +/- 2.1 micromol/L in the first and second trimesters respectively, with no significant modifications after three months of folic acid. Although the degree of desertion from the study was high, it was possible to determine the evolution of 65 pregnancies. Ten of them developed preeclampsia (15.4%). No significant differences were found in Hc concentrations, or the frequency of hyperhomocysteinemia in the different stages of pregnancy, between women with normal gestation and those who developed preeclampsia. The small sample size of these groups, preclude any valid conclusion, however the results do not suggest that Hc concentration or folic acid administration influence the development of toxemia of pregnancy.

Variations in the lipid profile of patients with chronic renal failure, treated with folic acid.

Dyslipidemia and increases in plasma homocysteine usually occur at end-stage renal disease; both are recognized as risk factors for atherosclerosis. Folate administration reduces homocysteine concentration. In this study we determined the effect of a high dose of folic acid (40 mg intravenous injection three times a week) on plasma and red blood cell lipid profiles in twelve chronic renal failure patients on regular hemodialysis. Fasting blood samples were taken at the beginning of the study (baseline) and after 21, 42, and 64 days of treatment. Folic acid supplementation decreased plasma homocysteine. Plasma triglyceride levels decreased whereas polyunsaturated fatty acid values increased after 21 days; then they returned to baseline levels at the end of treatment. Total cholesterol and low-density lipoprotein (LDL) cholesterol were higher than those of the baseline during all the study, whereas high-density lipoprotein (HDL) cholesterol was reduced. In erythrocyte membranes, folic acid therapy enhanced cholesterol/phospholipid ratios and the fluorescence anisotropy of diphenyl-hexatriene. We conclude that large doses of folic acid produce a favorable effect, reducing plasma homocysteine levels and protecting patients from atherosclerosis. However, as this therapy induces significant alterations in both plasma and erythrocyte membrane lipid profiles, plasma lipid values should be controlled throughout the treatment of patients with renal failure.

The C677T thermolabile variant of methylene tetrahydrofolate reductase on homocysteine, folate and vitamin B12 in a hemodialysis center.

Homocysteine is a risk factor for cardiovascular disease. Mutations in a key enzyme in homocysteine metabolism, methylenetetrahydrofolate reductase, may contribute to hyperhomocysteinemia and alter folate and cobalamin levels. After starting hemodialysis, 10 mg oral folate daily and 500 micrograms intravenous methylcobalamin once weekly were prescribed to 27 hemodialysis patients (time on hemodialysis > or = 12 months) and two groups were defined: Group A normal; Group B heterozygous. Initial, third and twelfth month measurements of homocysteine, serum folate and vitamin B12 levels were collected and analyzed. Heterozygous state of methylenetetrahydrofolate reductase prevalence was 48% and homozygozity 4%. Hyperhomocysteinemia was present in both groups. Cobalamin final levels were significantly lower in Group B compared to Group A. Homocysteine, serum folate and cobalamin levels at third and twelfth month were significantly different from baseline levels but non-different between them in both groups. In Group B, vitamin B12 at third month was significantly higher than initial, but final measurements were not different from baseline determinations. In conclusion, the heterozygous prevalence of the enzyme in hemodialysis patients is similar to that reported in the general population; hyperhomocysteinemia is frequent in hemodialysis patients and final levels in heterozygous patients are significantly higher than in normal patients. Cobalamin levels are lower in the heterozygous group. After one year of treatment, homocysteine tends to increase, suggesting a secondary resistance phenomenon to vitamin supplementation in heterozygous patients.

The Chilean flour folic acid fortification program reduces serum homocysteine levels and masks vitamin B-12 deficiency in elderly people.

Hyperhomocysteinemia is considered a risk factor for cardiovascular disease and is prevalent in the elderly. Supplementation with folic acid, vitamin B-6 and B-12 lowers homocysteine levels. In January 2000, the Chilean government initiated a flour folic acid fortification program to decrease the occurrence of neural tube defects. The aim of this study was to evaluate the effect of this program on serum homocysteine and folate levels in elderly subjects after 6 mo. A total of 108 elderly people were studied. We measured serum folate, homocysteine and vitamin B-12 levels before the fortification started and 6 mo later. At baseline, folate deficiency (<6.8 nmol/L) was present in 1.8%, vitamin B-12 deficiency (<165 pmol/L) in 27.6% and hyperhomocysteinemia (>14 micromol/L) in 31% of the sample. Six months later, serum folate levels increased from 16.2 +/- 6.2 to 32.7 +/- 7.1 nmol/L (P < 0.001), homocysteine levels decreased from 12.95 +/- 3.7 to 11.43 +/- 3.6 micromol/L (P < 0.001) and vitamin B-12 levels were unchanged. Flour fortification with folic acid had a moderate lowering effect on homocysteine levels. Given that vitamin B-12 deficiency was more common than folate deficiency, it may be more appropriate to add vitamin B-12 to food, at least in foods for this age group.

The C677T thermolabile variant of methylene tetrahydrofolate reductase on homocysteine, folate and vitamin B12 in a hemodialysis center

Homocysteine is a risk factor for cardiovascular disease. Mutations in a key enzyme in homocysteine metabolism, methylenetetrahydrofolate reductase, may contribute to hyperhomocysteinemia and alter folate and cobalamin levels. After starting hemodialysis, 10 mg oral folate daily and 500 micrograms intravenous methylcobalamin once weekly were prescribed to 27 hemodialysis patients (time on hemodialysis > or = 12 months) and two groups were defined: Group A normal; Group B heterozygous. Initial, third and twelfth month measurements of homocysteine, serum folate and vitamin B12 levels were collected and analyzed. Heterozygous state of methylenetetrahydrofolate reductase prevalence was 48

. Hyperhomocysteinemia was present in both groups. Cobalamin final levels were significantly lower in Group B compared to Group A. Homocysteine, serum folate and cobalamin levels at third and twelfth month were significantly different from baseline levels but non-different between them in both groups. In Group B, vitamin B12 at third month was significantly higher than initial, but final measurements were not different from baseline determinations. In conclusion, the heterozygous prevalence of the enzyme in hemodialysis patients is similar to that reported in the general population; hyperhomocysteinemia is frequent in hemodialysis patients and final levels in heterozygous patients are significantly higher than in normal patients. Cobalamin levels are lower in the heterozygous group. After one year of treatment, homocysteine tends to increase, suggesting a secondary resistance phenomenon to vitamin supplementation in heterozygous patients.