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Homocysteine metabolism in diabetes

E P Wijekoon1, M E Brosnan, J T Brosnan

  • 1Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X9.

Biochemical Society Transactions
|October 25, 2007
PubMed

Insights

Plasma homocysteine (Hcy) levels are lower in patients with diabetes. This study investigated Hcy metabolism in diabetes, finding altered enzyme activity contributes to reduced Hcy levels in both Type 1 and Type 2 diabetes.

Area of Science:

  • Biochemistry
  • Metabolic Research
  • Endocrinology

Background:

  • Elevated plasma homocysteine (Hcy) is a risk factor for cardiovascular disease (CVD).
  • CVD is a leading cause of mortality in diabetic patients.
  • Understanding Hcy metabolism in diabetes is crucial for disease management.

Purpose of the Study:

  • To investigate the alterations in homocysteine metabolism in diabetic patients.
  • To identify the specific metabolic pathways and enzymes involved in Hcy regulation in diabetes.
  • To elucidate the role of insulin and counter-regulatory hormones in Hcy metabolism during diabetes.

Main Methods:

  • Comparative analysis of plasma Hcy levels in diabetic patients (Type 1 and Type 2) and control groups.
  • Enzyme activity assays for key enzymes in Hcy metabolism, including trans-sulfuration pathway enzymes and betaine:homocysteine methyltransferase (BHMT).
  • In vitro studies to assess the direct effects of insulin and counter-regulatory hormones on enzyme activity.

Main Results:

  • Plasma Hcy levels were found to be lower in diabetic patients without renal complications compared to controls.
  • In Type 1 diabetes, increased activity of trans-sulfuration enzymes was the primary reason for reduced Hcy.
  • In Type 2 diabetes, both trans-sulfuration enzymes and BHMT showed increased activity, contributing to Hcy catabolism.

Conclusions:

  • Diabetes mellitus, independent of renal complications, is associated with reduced plasma homocysteine levels.
  • Altered activities of trans-sulfuration enzymes and BHMT, influenced by insulin and counter-regulatory hormones, explain the modified Hcy metabolism in diabetes.
  • These findings provide insights into the complex interplay between diabetes and Hcy metabolism, potentially impacting CVD risk stratification.

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