IN-VITRO EFFECTS OF IONIC AND NONIONIC CONTRAST-MEDIA ON RED-BLOOD-CELLS AGGREGATION

An in vitro model was designed to examine the effect of three contrast media (CM) : two non ionic (Iohexol, Iopamidol) and one ionic (Ioxagl ate) molecules on erythrocyte aggregation. Red blood cells were suspen ded in a chemically defined medium (Albumin : 10 g/l), Immunoglobulins : 12 g/l, Fibrinogen : 1.5 g/1) supplemented with various proportions of CM (10-25% V/V). Control samples contained NaCl or Saccharose solu tions with a nearly similar osmolality. Erythrocyte aggregation at con stant hematocrit (HT = 40%) was determined by the analysis of the ligh t backscattered by blood suspension during the aggregation process. As compared to control samples, non ionic CM induced a weak decrease in erythrocyte aggregation, when the ionic molecule caused a marked incre ase in the aggregation, which was related to CM concentration. A diffe rent interaction of ionic and non ionic CM with erythrocyte membranes has been shown by fluorescence studies. After addition of CM, it was n oted a fluorescence quenching of lipophilic probes (TMA-DPH and DPH) e mbedded in erythrocyte membranes. This quenching probably due to benze ne ring and iodine atoms of contrast media markedly varied according t o the used fluorescent probe and the CM. In the presence of ionic CM, the fluorescence quenching is more important than that induced by non ionic CM. Thus, besides osmolality and viscosity of CM which play a ro le in erythrocyte aggregation, some intrinsic properties of CM such as the ionic or non ionic nature could influence erythrocyte membrane-co ntrast medium interactions and consequently erythrocyte aggregation (J Mal Vasc, 1993, 18, pages 135-143).