Myocardial Infarction Changes Sphingolipid Metabolism in the Uninfarcted Ventricular Wall of the Rat

It is known that the ratio, the level of sphingosine-1-phosphate (S1P)/the level of ceramide (CER) determines survival of the cells. The aim of the present study was to examine the effect of myocardial infarction on the level of different sphingolipids in the uninfarcted area. The experiments were carried out on male Wistar rats: 1, control; 2, after ligation of the left coronary artery (infarct) and 3, sham operated. Samples of the uninfarcted area of the left ventricle were taken in 1, 6 and 24 h after the surgery. The level of sphingolipids, S1P, CER, sphingosine (SPH), sphinganine-1-phosphate (SPA1P) and sphinganine (SPA) was determined. The control values were (ng/mg), S1P-0.33 +/- A 0.03, SPH-1.02 +/- A 0.13, SPA1P-0.11 +/- A 0.01, SPA-0.28 +/- A 0.04, total CER-20.3 +/- A 1.8. In infarct, the level of S1P in the uninfarcted area was reduced by similar to 3 times in 1 and 6 h and decreased further in 24 h. The level of SPH decreased in 1 h and returned to the control thereafter. The total level of CER decreased in 6 h after the infarction. Sham surgery also produced changes in the level of certain sphingolipids. The ratio, the level of S1P/the level of CER was markedly reduced at each time point after the infarction. It is concluded that the reduction in the S1P/CER ratio could be responsible for increased apoptosis in the uninfarcted area after the myocardial infarction in the rat.