FATTY-ACID-BINDING PROTEINURIA DIAGNOSES MYOCARDIAL-INFARCTION IN THERAT

Cytoplasmic heart-type fatty acid-binding protein (H-FABP(c)) is a low molecular weight protein with abundant presence in the myocardium. Up on ischemia it is released from the heart and can subsequently be dete cted in plasma and urine. In this study, the value of measurement of H -FABP(c) excreted into urine for the diagnosis of myocardial infarctio n (MI) is investigated in the rat. To this end, firstly the kinetic be haviour of H-FABP(c) in plasma was examined and its release into urine quantified. After injection of purified H-FABP(c) in normal animals, a net recovery in urine of 14-29% was found. The kinetic behaviour of H-FABP(c) in plasma was characterized by a total clearance of 0.33 ml/ min and a half-life value of total elimination of about 270 min. Knowi ng these plasma characteristics of H-FABP(c), a comparison was made be tween the cumulative amounts of H-FABP(c) released in the 24-hour urin e of MI rats and of sham-operated animals. In MI rats, with a mean mor phometric MI size of 43%, the mean total amount of H-FABP(c) excreted into urine was 79 mug, while in sham-operated rats this was 23 mug. Th is difference between both groups is significant (p < 0.001). It is co ncluded that urinary H-FABP(c) can be used as a noninvasive marker for MI in the rat.