Plasma Homocysteine, Methylenetetrahydrofolate Reductase Gene Polymorphism and Carotid Intima-media Thickness in Italian Type 2 Diabetic Patients

Background: Moderately elevated levels of homocysteine have been associated with an increased cardiovascular risk in type 2 diabetic patients. The role of methylenetetrahydrofolate reductase gene polymorphism is less clear.

Materials And Methods: We investigated the contribution of plasma homocysteine levels and the methylenetetrahydrofolate reductase gene polymorphism to the variability of carotid intima-media thickness in 124 consecutive Italian patients with type 2 diabetes mellitus. Fasting plasma homocysteine was measured by high-pressure liquid chromatography with an electrochemical detector; methylenetetrahydrofolate reductase genotypes were determined by polymerase chain reaction and restriction enzyme digestion. The carotid intima-media thickness was evaluated with high-resolution B-mode ultrasonography.

Results: Age, creatinine and plasma homocysteine levels showed a positive correlation with mean carotid intima-media thickness values, but only age and creatinine levels were still associated with mean carotid intima-media thickness values in the multivariate analysis. Plasma homocysteine levels were significantly higher in the patients bearing the 677T/677T genotype of the methylenetetrahydrofolate reductase polymorphism; mean carotid intima-media thickness values were not different in the three different methylenetetrahydrofolate reductase genotypes.

Conclusion: In 124 Italian patients with type 2 diabetes mellitus, basal levels of plasma homocysteine, as well as methylenetetrahydrofolate reductase gene polymorphism, did not explain the variability of mean carotid intima-media thickness.