Total plasma homocysteine determination by liquid chromatography before and after methionine loading - Results in cerebrovascular disease

Elevated homocysteine (HCY) levels in tissues and blood are associated with premature occlusive diseases. A number of techniques have been developed to assay HCY, including high-performance liquid chromatography (HPLC) with fluorimetric or electrochemical detection, and radioenzymatic methods. The present study evaluated the adaptation of a liquid chromatographic, ion-exchange technique with postcolumn derivatization using ninhydrin. Fasting and moreover post methionine load total plasma HCY were assayed in 50 patients three months after a stroke and in 20 age-matched controls. Ion-exchange liquid chromatography was performed on an amino acid analyzer using a modified procedure to improve methionine and HCY separation. HCY values in the fasting slate were moderately but significantly increased (P < 0.05) in the patients compared to the controls: 10.5 +/- 3.4 versus 9.3 +/- 2.3 mu mol/l. The difference between the two groups was amplified in post-load HCY results, which were significantly increased (P < 0.05) in the patients: 41.6 +/- 17.8 versus 29.2 +/- 5.5 mu mol/l in controls. The relationship between cerebrovascular disease and impaired HCY metabolism has previously been emphasized by other investigators. Our findings suggest that certain inherited and/or acquired HCY disorders observed in the fasting state (14%) and especially in post-methionine load conditions (32%) may occur during acute disease, and that total plasma HCY can be determined by ion-exchange chromatography even after oral methionine loading.