Dataset Information

Evaluation of tracer labelled methionine load test in vitamin B-12 deficient adolescent women.

ABSTRACT:

Background

Methionine loading test (MLT) has been used primarily to identify defects in transsulfuration of homocysteine in cystathionine beta synthase deficiency. It may not be as useful to evaluate remethylation pathway, in vitamin B-12 and folate deficiencies.

Objective

We used tracer isotope labelled MLT to interrogate transsulfuration and remethylation independently in vitamin B-12 deficiency.

Design

We studied vitamin B-12 deficient women with a tracer labelled MLT before and eleven months after treatment with vitamin B-12. The fractional contribution of [13C]homocysteine to breath CO2 was used as a measure of transsulfuration, and difference in the intracellular enrichment of [13C]methionine and that of [C2H3]methionine as a measure of remethylation of homocysteine. Combined pre- and post-treatment results were analyzed to investigate the association between plasma vitamin B-12 concentrations and measures of homocysteine metabolism.

Results

The subjects were 17 years old, with a BMI of 19.4 kg/m2. Treatment with vitamin B-12, 2µg/day increased plasma B-12 from 93 (78.7, 106.2) [median (25th, 75th centiles)] to 161.5 (125.5, 226.2) pmol/L; 44% were below <150pmol/L after treatment. Fasting homocysteine concentration was significantly lower and that of cysteine higher in subjects with B-12 levels >150pmol/L. The tracer estimated transsulfuration of homocysteine was lower and remethylation higher with B-12 levels >150pmol/L when compared with those <150pmol/L.

Conclusions

The tracer labelled MLT in combination with fasting parameters is a robust way to estimate parameters of methionine metabolism and can be used in the field where prime-constant rate infusion studies cannot be done efficiently.

SUBMITTER: Bhat DS

PROVIDER: S-EPMC5967743 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evaluation of tracer labelled methionine load test in vitamin B-12 deficient adolescent women.

Bhat Dattatray S DS Gruca Lourdes L LL Bennett Carole D CD Katre Prachi P Kurpad Anura V AV Yajnik Chittaranjan S CS Kalhan Satish C SC

PloS one 20180524 5

<h4>Background</h4>Methionine loading test (MLT) has been used primarily to identify defects in transsulfuration of homocysteine in cystathionine beta synthase deficiency. It may not be as useful to evaluate remethylation pathway, in vitamin B-12 and folate deficiencies.<h4>Objective</h4>We used tracer isotope labelled MLT to interrogate transsulfuration and remethylation independently in vitamin B-12 deficiency.<h4>Design</h4>We studied vitamin B-12 deficient women with a tracer labelled MLT be ...[more]

PMID: 29795596

Similar Datasets

Project description:BackgroundVitamin B-12 deficiency is often considered synonymous with pernicious anemia, a rare condition in which severe malabsorption of the vitamin requires high-dose parenteral treatment. In developing countries such as India, inadequate dietary intake of B-12 due to socio-cultural factors leads to widely prevalent asymptomatic low B-12 status. In this scenario, lower doses of oral B-12 may be effective, safer and more affordable.ObjectiveTo examine the effects of oral B-12 treatment at physiological doses on hematological and biochemical indices and peripheral nerve function in B-12 deficient rural Indian adolescent women.MethodsThirty-nine women with B-12 deficiency who were excluded from a community based B-12 supplementation trial (Pune Rural Intervention in Young Adolescents (PRIYA)) received oral B-12 2?g/day, either alone (n = 19) or with multiple micronutrients (UNIMAPP formula + 20gm milk powder, n = 20) for 11 months. Hematological indices, nutrients (B-12, folate), metabolites (homocysteine) and peripheral nerve function (SUDOSCAN, Impetomedical, Paris and sensory nerve conduction velocity (NCV) of median and sural nerves) were assessed at baseline and after 11 months of B-12 treatment.ResultsResults were similar in the two treatment allocation groups, which were therefore combined. At baseline, all women had B-12 concentration <100pmol/L, 79% were anemic and 33% had macrocytosis, but none had neuropathy. After 11 months of treatment, B-12 levels increased, while folate did not change. The prevalence of anemia fell to 59% and mean corpuscular volume (MCV) and plasma homocysteine concentrations decreased. Sudomotor nerve function in the feet improved by an average of 14.7%, and sensory conduction velocity in median and sural nerves increased by 16.2% and 29.4% respectively.ConclusionWe document clinically beneficial effects of supplementation with a physiological dose of oral B-12 in asymptomatic rural Indian adolescent women with very low B-12 status. These findings support a public health approach to tackle the widely prevalent low B-12 status in young Indians.

Dataset Information

Evaluation of tracer labelled methionine load test in vitamin B-12 deficient adolescent women.

Background

Objective

Design

Results

Conclusions

Publications

Evaluation of tracer labelled methionine load test in vitamin B-12 deficient adolescent women.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets