Increase In Plasma Methionine Research Articles

242 Effects of different carbohydrate sources on taurine status in healthy Beagle dogs

Abstract Consumption of grain-free (GF) diets has recently been linked to canine dilated cardiomyopathy in selected dog breeds. Soluble fiber present in GF carbohydrate sources may be contributing to taurine depletion, thus affecting heart health. The objective of this study was to evaluate the effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Two practical diets sufficient in sulfur-amino acids and taurine were formulated with the same proportion of carbohydrate sources: a grain-based (GB) containing sorghum, millet, and spelt, and a GF containing peas, potatoes and tapioca starch. Twelve Beagle dogs were fed experimental diets for 4-wk in a randomized complete block design. The morning prior to feeding experimental diets (baseline) and two and four weeks after, markers of taurine metabolism were analyzed in blood, urine, and fresh fecal samples. Data were analyzed as a change from baseline in a repeated measures model by GLIMMIX (SAS, version 9.4) in which the main effects of time, diet, and their interaction were evaluated. Greater concentrations of taurine in plasma (158 vs. 117 nmol/mL) and whole blood (254 vs. 234 nmol/mL) were observed during experimental period compared to baseline. An increase in plasma methionine was also observed during experimental period compared to baseline (64 vs. 57nmol/mL). Dogs fed GF exhibited higher plasma taurine concentration compared to those fed GB (181 vs. 138 nmol/mL). There were no significant effects of diet, time, or their interaction on plasma cystine concentration, urinary taurine:creatinine ratio, or total fecal bile acid (BA) excretion (P > 0.05). However, dogs fed GF had greater fecal primary BA (26 vs 14%) as a proportion of total BA compared to those fed GB. This study suggests that GF diets do not impair taurine blood concentration, but the increased proportion of fecal primary BA may decrease recycling of taurine through enterohepatic circulation.

Open-Label Trial of Vitamin D3 Supplementation in Children with Autism Spectrum Disorder

JOURNAL OF CHILD AND ADOLESCENT PSYCHOPHARMACOLOGY Volume X, Number x, 2016 a Mary Ann Liebert, Inc. Pp. 1–10 DOI: 10.1089/cap.2015.0159 Original Article Randomized, Placebo-Controlled Trial of Methyl B12 for Children with Autism Robert L. Hendren, DO, 1 S. Jill James, PhD, 2 Felicia Widjaja, MPH, 1 Brittany Lawton, BS, 1 Abram Rosenblatt, PhD, 1 and Stephen Bent, MD 1 Abstract Objective: Children with autism spectrum disorder (ASD) have been reported to have reduced ability to methylate DNA and elevated markers of oxidative stress. We sought to determine if methyl B12, a key metabolic cofactor for cellular methylation reactions and antioxidant defense, could improve symptoms of ASD. Methods: A total of 57 children with ASD were randomly assigned to 8 weeks of treatment with methyl B12 (75 lg/kg) or saline placebo every 3 days in a subcutaneous injection. The primary outcome measure was overall improvement in symptoms of ASD as measured by the Clinical Global Impressions-Improvement (CGI-I) score. Secondary outcome mea- sures included changes in the Aberrant Behavior Checklist (ABC) and the Social Responsiveness Scale (SRS). Laboratory measures of methionine methylation and antioxidant glutathione metabolism were assessed at baseline and 8 weeks. Results: A total of 50 children (mean age 5.3 years, 79% male) completed the study. The primary outcome measure – the clinician rated CGI-I score – was statistically significantly better (lower) in the methyl B12 group (2.4) than in the placebo group (3.1) (0.7 greater improvement in the methyl B12 group, 95% CI 1.2–0.2, p = 0.005). Clinical improvement among children treated with methyl B12 was positively correlated with increases in plasma methionine ( p = 0.05), decreases in S-adenosyl-l- homocysteine (SAH) ( p = 0.007) and improvements in the ratio of S-adenosylmethionine (SAM) to SAH ( p = 0.007), indi- cating an improvement in cellular methylation capacity. No improvements were observed in the parent-rated ABC or SRS. Conclusions: Methyl B12 treatment improved clinician-rated symptoms of ASD that were correlated with improvements in measures of methionine metabolism and cellular methylation capacity. Clinical Trial Registry: Efficacy Study of Subcutaneous Methyl B12 in Children with Autism: NCT01039792 (clinical trials.gov1). Introduction with autism had significantly lower plasma methionine, S- adenosylmethionine (SAM), homocysteine, cystathionine, cysteine, and total glutathione as well as significantly higher levels of S-adenosyl-l-homocysteine (SAH), adenosine, and oxidized gluta- thione. These laboratory changes were consistent with increased oxidative stress and impaired methylation capacity in children with ASD ( James et al. 2004). As shown in Figure 1, these abnormalities are related to three interconnected metabolic pathways known col- lectively as methionine transmethylation/transsulfuration metabo- lism (Hirsch et al. 2008; Kalinina et al. 2014; Watson et al. 2014). A second study in 2006 of 80 children with ASD and 73 controls again demonstrated the same pattern of methylation deficit and oxidative stress ( James et al. 2006). A more recent study in 2012 examined 68 children with ASD, 40 unaffected siblings, and 54 age- matched unaffected, unrelated control children. Reduced methyla- tion capacity was associated with DNA hypomethylation and reduced glutathione antioxidant defense in the children with ASD but not in their unaffected siblings or control children (Melnyk et al. A utism spectrum disorder (ASD) is a complex neurodeve- lopmental disorder characterized by deficits in social inter- action and restricted, repetitive patterns of behavior that now affects 1 in 68 children (Developmental Disabilities Monitoring Network Surveillance Year Principal and Centers for Disease Control and Prevention 2014). ASD has a significant genetic component, with up to 25% of cases being caused by an identifiable genetic defect (Huguet et al. 2013). However, two recent epide- miologic studies have concluded that environmental influences have a greater contribution than genetic factors in the etiology of autism (Hallmayer et al. 2011; Sandin et al. 2014). Many metabolic processes have shown specific deficits in children with ASD, including both cellular methylation and glutathione- mediated antioxidant defense (Rossignol and Frye 2012). In 2004, James et al. reported findings of a small study of 20 children with autism compared with 33 healthy controls, and found that children Department of Psychiatry, University of California, San Francisco, California. Arkansas Children’s Hospital Institute, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas. Funding: This study was supported by a grant from Autism Speaks (grant #3031 to Dr. Hendren).

Randomized, Placebo-Controlled Trial of Methyl B12 for Children with Autism.

Children with autism spectrum disorder (ASD) have been reported to have reduced ability to methylate DNA and elevated markers of oxidative stress. We sought to determine if methyl B12, a key metabolic cofactor for cellular methylation reactions and antioxidant defense, could improve symptoms of ASD. A total of 57 children with ASD were randomly assigned to 8 weeks of treatment with methyl B12 (75 μg/kg) or saline placebo every 3 days in a subcutaneous injection. The primary outcome measure was overall improvement in symptoms of ASD as measured by the Clinical Global Impressions-Improvement (CGI-I) score. Secondary outcome measures included changes in the Aberrant Behavior Checklist (ABC) and the Social Responsiveness Scale (SRS). Laboratory measures of methionine methylation and antioxidant glutathione metabolism were assessed at baseline and 8 weeks. A total of 50 children (mean age 5.3 years, 79% male) completed the study. The primary outcome measure - the clinician rated CGI-I score - was statistically significantly better (lower) in the methyl B12 group (2.4) than in the placebo group (3.1) (0.7 greater improvement in the methyl B12 group, 95% CI 1.2-0.2, p = 0.005). Clinical improvement among children treated with methyl B12 was positively correlated with increases in plasma methionine (p = 0.05), decreases in S-adenosyl-l-homocysteine (SAH) (p = 0.007) and improvements in the ratio of S-adenosylmethionine (SAM) to SAH (p = 0.007), indicating an improvement in cellular methylation capacity. No improvements were observed in the parent-rated ABC or SRS. Methyl B12 treatment improved clinician-rated symptoms of ASD that were correlated with improvements in measures of methionine metabolism and cellular methylation capacity. Clinical Trial Registry: Efficacy Study of Subcutaneous Methyl B12 in Children with Autism: NCT01039792 ( clinicaltrials.gov1 ).

Choline-related supplements improve abnormal plasma methionine-homocysteine metabolites and glutathione status in children with cystic fibrosis

Background:Liver triacylglycerol accumulation and oxidative stress are common in cystic fibrosis (CF) and also occur in choline deficiency. Previously, we showed an association between elevated plasma homocysteine, reduced ratios of S-adenosylmethionine to S-adenosylhomocysteine (SAM:SAH) and of phosphatidylcholine to phosphatidylethanolamine, and phospholipid malabsorption in children with CF.Objective:The objective was to address a possible relation between altered methionine-homocysteine metabolism and choline metabolism in children with CF.Design:Children with CF were assigned without bias to supplementation with 2 g lecithin/d (n= 13), 2 g choline/d (n= 12), or 3 g betaine/d (n= 10) for 14 d. Plasma concentrations of methionine, adenosine, cysteine, cysteinyl-glycine, glutathione, glutathione disulfide (GSSG), and fatty acids; SAM:SAH; and red blood cell phospholipids were measured within each group of children with CF before and after supplementation. Plasma from healthy children without CF (n= 15) was analyzed to obtain reference data.Results:Children with CF had higher plasma homocysteine, SAH, and adenosine and lower methionine, SAM:SAH, and glutathione:GSSG than did children without CF. Supplementation with lecithin, choline, or betaine resulted in a significant increase in plasma methionine, SAM, SAM:SAH, and glutathione:GSSG and a decrease in SAH (n= 35). Supplementation with choline or betaine was associated with a significant decrease in plasma SAH and an increase in SAM:SAH, methionine, and glutathione:GSSG. Supplementation with lecithin or choline also increased plasma methionine and SAM.Conclusion:We showed that dietary supplementation with choline-related compounds improves the low SAM:SAH and glutathione redox balance in children with CF.

Absence of limiting amino acids in calves fed a corn and soybean meal diet past three months of age.

We conducted three nitrogen balance trials using Holstein bull calves older than 16 wk (Trial 1; n = 8), 13 wk (Trial 2; n = 6), and 15 wk of age (Trial 3; n = 9) in a 4 x 4 (Trial 1) or 3 x 3 Latin square design (Trials 2 and 3) to identify limiting amino acids for a corn and soybean meal diet. All calves were trained to maintain reflex closure of the reticular groove after weaning at 5 wk of age. The basal diet was fed daily at 20 or 27 g/kg BW (Trial 1) and at 20 g/kg BW (Trials 2 and 3). The lower feeding level resulted in reduced urinary excretion of purine derivatives, suggesting reduced synthesis of ruminal microbial protein (Trial 1). In Trials 1 and 2, administration of DL-methionine plus L-lysine monohydrochloride through the reticular groove did not increase N retention compared with the supplement of isonitrogenous L-glutamine at either level of intake. In Trial 3, administration of either casein or isonitrogenous monosodium glutamate increased N retention to a similar extent above that observed with a N-free supplement. Results suggested that no specific amino acids were limiting for the corn-soybean meal diet. Administration of methionine plus lysine resulted in a remarkable increase in plasma methionine (Trials 1 and 2), especially at the lower intake level (Trial 1), and a decrease in plasma branched-chain amino acids at either intake level. Glutamine supplementation did not increase plasma branched-chain amino acids compared with the supplementation of diammonium citrate (Trial 2).

Plasma Concentrations of Homocysteine and Other Aminothiol Compounds Are Related to Food Intake in Healthy Human Subjects

We investigated total, free and protein-bound plasma homocysteine, cysteine and cysteinylglycine in 13 subjects aged 24-29 y after a breakfast at 0900 h containing 15-18 g of protein and a dinner at 1500 h containing approximately 50 g of protein. Twelve subjects had normal fasting homocysteine (mean +/- SD, 7.6 +/- 1.1 mumol/L) and methionine concentrations (22.7 +/- 3.5 mumol/L) and were included in the statistical analyses. Breakfast caused a small but significant increase in plasma methionine (22.2 +/- 20.6%) and a brief, nonsignificant increase followed by a significant decline in free homocysteine. However, changes in total and bound homocysteine were small. After dinner, there was a marked increase in plasma methionine by 16.7 +/- 8.9 mumol/L (87.9 +/- 49%), which was associated with a rapid and marked increase in free homocysteine (33.7 +/- 19.6%, 4 h after dinner) and a moderate and slow increase in total (13.5 +/- 7.5%, 8 h) and protein-bound (12.6 +/- 9.4%, 8 h) homocysteine. After both meals, cysteine and cysteinylglycine concentrations seemed related to changes in homocysteine, because there were parallel fluctuations in the free:bound ratios of all three thiols. Dietary changes in plasma homocysteine will probably not affect the evaluation of vitamin deficiency states associated with moderate to severe hyperhomocysteinemia but may be of concern in the risk assessment of cardiovascular disease in patients with mild hyperhomocysteinemia. Synchronous fluctuations in the free:bound ratio of the plasma aminothiol compounds indicate that biological effects of homocysteine may be difficult to separate from effects due to associated changes in other aminothiol compounds.

Kinetics of plasma homocysteine in healthy subjects after peroral homocysteine loading

The kinetics of plasma homocysteine were determined in 13 healthy subjects after peroral administration and in one person after intravenous injection. Various forms of homocysteine completely dissolved in an aqueous solution were rapidly absorbed after peroral administration, and the bioavailability was estimated to be 0.53. The volume of distribution was 0.66 L/kg. The area under the plasma concentration curve (AUC0-48 h) was proportional to the administered dose (33.5-134 mumol/kg body wt), and showed small interindividual variations. Plasma homocysteine showed first-order elimination kinetics for at least 6 h. The half-life (t1/2) was 223 +/- 45 min, and there was a significant correlation between t1/2 values determined on two different occasions in the same individual. The transient hyperhomocysteinemia was associated with an increase in plasma methionine, which probably reflects intracellular remethylation of homocysteine. Less than 2% of the administered homocysteine dose was recovered in the urine. These findings may form the basis for future studies on the regulation of plasma homocysteine in health and disease, and should motivate the evaluation of a homocysteine loading test as a diagnostic tool.

Estimation of Lysine and Methionine Requirements of Growing Steers Fed Corn Silage-Based or Corn-Based Diets

Methionine and lysine requirements of growing steers were studied. Steers (Experiment 1, 313kg) fed 6.4kg of an 80% corn silage diet (1.38% N) had duodenal flows of methionine, cysteine, and lysine of 9.7, 10.7, and 40.2 g/d. Linear increases in plasma methionine and plasma lysine in response to abomasal infusions of DL-methionine and L-lysine indicated that requirements for methionine and lysine were met by basal flows or that neither lysine nor methionine was the first or sole limiting amino acid. Steers (Experiment 2, 383kg) fed 7.5kg of a 75% corn diet (1.55% N) had methionine, cysteine, and lysine flows at the duodenum of 13.8, 16.1, and 52.9 g/d. Abomasal infusions of DL-methionine resulted in linear increases in plasma methionine, but abomasal infusions of L-lysine resulted in two-phase broken line plasma amino acid response curves. For steers infused with lysine alone, the breakpoint occurred at 4 g/d infused lysine, whereas steers receiving 9 g/d DL-methionine had a breakpoint at 8 g/d infused lysine. The total absorbable lysine requirement was estimated to be 44 to 48 g/d, depending upon methionine status. Rumen-protected amino acids fed to steers on both dietary regimens were effective in supplying methionine and lysine postruminally.

The Use of Low Protein Liquid Diets to Determine the Methionine Requirement and the Efficacy of Methionine Hydroxy Analogue for the Three-Week-Old Pig

A mechanical feeding device that dispenses liquid diets hourly was developed to feed 3-week-old pigs under carefully controlled and sanitary conditions. Pigs were weaned at 19–21 days of age, placed in individual cages of the automatic feeder, and trained to eat low protein (9%) milk diets, which were supplemented with essential amino acids, glutamic acid and monosodium glutamate so as to be equivalent to 14% protein nitrogen. The basal 9% protein diet contained 0.25% L-methionine and 0.08% L-cysteine and was supplemented with L- or DL-methionine or DL-methionine hydroxy analogue (MHA) at various levels for evaluation of the methionine requirement. Pigs fed the basal diet showed a significant decrease in gain, feed efficiency and plasma urea (P < 0.05) relative to animals that received supplemental methionine or MHA. The plasma methionine concentration remained below 0.2 µmol/ml plasma when pigs were fed diets containing 0.25–0.51% methionine; however, a significant increase in plasma methionine (P < 0.05) was seen when pigs were fed diets that contained greater than 0.51% methionine activity in the form of L- or DL-methionine or DL-MHA. The highest average daily gain (470 g) obtained with a diet containing 0.51% methionine was significantly better (P < 0.05) than diets containing more or less L- or DL-methionine, and the feed efficiency of this diet (1.58 kg feed per kilogram gain) was also significantly better (P < 0.05) than the feed efficiency obtained with other dietary methionine levels. MHA (0.17%) added to the basal diet significantly improved the average daily gain (P < 0.05) and lead to a significant decrease in plasma urea (P < 0.05) relative to pigs that received the basal diet. Supplemental MHA (>0.51% methionine level) produced significant increases (P < 0.05) in plasma methionine. These data show that the methionine requirement of the 3-week-old pig can be satisfied with L- or DL-methionine or DL-MHA at a level equal to 0.51% of the dietary solids and that these three are equivalent. These experiments also show that low protein diets supplemented with amino acids can be used for liquid feeding of pigs weaned at 3 weeks of age, and average daily gains of greater than 400 g can be realized.

Influence of Copper Supplementation on the Relationship between Dietary Methionine and Free Plasma Methionine

One-day-old broiler chicks were adapted to a basal, isolated soyprotein-cornstarch diet containing 20% protein, 0.59% methionine and 3,300 kcal metabolizable energy (ME)/kg. They were then fed experimental diets consisting of three levels (0, 500, 1,000 ppm) of copper added to each of the basal diet plus four levels (0, 0.4, 0.8, or 1.5%) of L-methionine for 1 or 4 weeks. Growth was retarded after 1 week by all levels of supplementary methionine, and by 500 or 1,000 ppm excess copper. The plasma concentrations of free methionine, serine, α-aminobutyric acid and cystathionine were increased by excess dietary methionine. Excess copper prevented the increase in plasma methionine. After 4 weeks, the plasma methionine concentration and rate of growth of chicks fed 0.4% excess L-methionine did not differ significantly from basal values. The growth retardation caused by 500 ppm excess copper was alleviated by 0.4% supplemental methionine, and the elevations in plasma methionine and liver and spleen iron concentrations observed in chicks fed 1.5% excess methionine were reduced by 1,000 ppm excess copper. The patterns of the relationship between dietary methionine and liver or spleen iron, in the presence or absence of supplementary copper, were similar to those between dietary and free plasma methionine.methionine copper toxicity

Concentrations of amino acids and urea in the plasma of the preruminant calf and estimation of the amino acid requirements.

1. A study was made of factors affecting the plasma concentrations of free amino acids (PAA) and urea (PU) in calves receiving liquid diets. 2. When calves were given whole milk (approximately 0-05 kg/kg live weight) at 10.00 and 17.00 hours there were marked decreases in PAA and slight decreases in PU for about 3-4 h after the morning feed. Both PAA and PU thereafter increased slightly and then remained constant for the next 10 h. In subsequent comparative experiments samples were taken 3 h after the morning feed. The variation in plasma methionine, isoleucine, leucine, phenylalanine, tyrosine and total PAA was apparently greater between than within animals. 3. In calves transferred from a diet of whole milk to one consisting of diluted whole milk supplemented with appropriate nutrients, including amino acids, but deficient in methionine, PU increased markedly and plasma methionine decreased. 4. Two calves (50-60 kg live weight) given the latter diet supplemented to give an intake of more than 4-5 g L-methionine/d together with 0-3 g cystine/d showed marked increases in plasma methionine. This was considered to correspond with the point at which methionine requirements were met and that under these conditions the methionine requirement for these calves (mean value plus or minus SE) was 4-5 plus or minus 0-2 g/d. In the same two calves PU decreased markedly with increasing levels of methionine supplementation up to 3-9 g/d and the estimated methionine requirement (mean value plus or minus SE) was 3-9 plus or minus 0-4 g/d.

Growth and Plasma Amino Acid Pattern of Chicks Fed Fish Meal as Sole Source Protein: Effect of Dietary Levels of Chloride, Sulfate, Glutamic Acid and Methionine

Two experiments were conducted with chicks fed fish meal as sole source protein from day 1 to day 21 to determine the effect (1) of lowered dietary chloride and sulfate content, (2) of additions of glutamic acid, and (3) of methionine on the growth response and on the plasma free amino acid pattern. These treatments produced characteristic effects on growth and the amino acid concentration in the plasma, indicating complex interactions. Decreasing the chloride and sulfate in a diet containing 12% protein supplied entirely by a fish meal produced a significant positive growth response which was apparently due to the resulting increased availability of arginine and increased concentration in the plasma. Supplementation of glutamic acid (5.05%) to the suboptimal 12% protein diet resulted in an increase in plasma glutamic acid and alanine, but increased growth occurred only when the diet also contained the higher level of chloride and sulfate. The addition of glutamic acid decreased the plasma concentration of threonine, serine, tyrosine, and phenylalanine.Methionine additions failed to increase growth unless glumatic acid was also included in the diet with the lower chloride and sulfate content. The 0.2% methionine supplement with glutamic acid produced a growth response and an increase in plasma methionine, cystathionine, and α-amino butyric acid. When 0.6% methionine was added to the diet, the plasma levels of these three amino acids were higher, resulting in a growth depression. Both levels of methionine supplements in combination with the glutamic acid caused a drop in the plasma lysine, threonine, valine, and histidine.