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 d eveloped to assay HCY, including high-performance liquid chromatograph y (HPLC) with fluorimetric or electrochemical detection, and radioenzy matic 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 plas ma HCY were assayed in 50 patients three months after a stroke and in 20 age-matched controls. Ion-exchange liquid chromatography was perfor med on an amino acid analyzer using a modified procedure to improve me thionine and HCY separation. HCY values in the fasting slate were mode rately 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 differ ence between the two groups was amplified in post-load HCY results, wh ich 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 betwee n cerebrovascular disease and impaired HCY metabolism has previously b een emphasized by other investigators. Our findings suggest that certa in inherited and/or acquired HCY disorders observed in the fasting sta te (14%) and especially in post-methionine load conditions (32%) may o ccur during acute disease, and that total plasma HCY can be determined by ion-exchange chromatography even after oral methionine loading.