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Methionine metabolism in human pregnancy
Jaividhya Dasarathy1, Lourdes L Gruca, Carole Bennett
1Department of Family Medicine, Case Western Reserve University School of Medicine at MetroHealth Medical Center, Cleveland, OH, USA.
The American Journal of Clinical Nutrition
|November 27, 2009
Summary
Pregnancy alters methionine metabolism, with higher transsulfuration rates early on and increased transmethylation later. These changes in methionine and homocysteine impact maternal health and fetal development.
Area of Science:
- Nutritional biochemistry
- Maternal-fetal medicine
- Metabolic research
Background:
- Pregnancy-associated hyperhomocysteinemia links to adverse outcomes like neural tube defects and preeclampsia.
- Human pregnancy's adaptive changes in methionine metabolism remain unclear.
Purpose of the Study:
- To investigate methionine transsulfuration and transmethylation kinetics in healthy pregnant women.
- To compare these metabolic rates across trimesters and with nonpregnant individuals.
Main Methods:
- Utilized stable isotope tracers ([1-(13)C]methionine, [C(2)H(3)]methionine, [(2)H(5)]phenylalanine) for whole-body rate of appearance (Ra) measurements.
- Infusions were administered to healthy pregnant women (trimesters 1, 2, 3) and nonpregnant controls.
- Assessed the impact of enteral nutrient loads on tracer kinetics.
Main Results:
- Phenylalanine Ra was lower in early pregnancy and increased with gestational age.
- Methionine transsulfuration rates were higher in the first trimester.
- Methionine transmethylation rates increased in the third trimester, with lower plasma cysteine and homocysteine levels during pregnancy.
Conclusions:
- Human pregnancy involves dynamic shifts in methionine metabolism: increased transsulfuration early and transmethylation late in gestation.
- Findings offer insights into methionine and homocysteine roles in pregnancy complications.
- Results inform nutritional support strategies for pregnant women.
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