Ionic and non-ionic contrast agent-mediated endothelial injury. Quantitative analysis of cell proliferation during endothelial repair.

PURPOSE: To quantitatively evaluate endothelial injury in vivo and to assess the time course of cellular repair after endothelial cell exposure to ionic and non-ionic contrast media.
MATERIAL AND METHODS: Local changes at the cellular level following intraaortic injection of 1 ml of the ionic contrast agent ioxithalamate or 1 ml of the non-ionic contrast agent iomeprol, each with an iodine content of 300 mg/ml, were investigated using rat endothelium as an in vivo model. A sorbitol solution iso-osmolar to iomeprol served as control. Quantitative analysis of endothelial changes by autoradiography of 3H-thymidine-labeled endothelial cells was assessed after 3, 5 and 10 days, determining the 3H-thymidine index and the DNA synthesis rate.
RESULTS: Ioxithalamate showed a clear harmful effect on the endothelium, with an elevated 3H-thymidine index of 7.68% on day 3 and 6.89% on day 5, versus 2.97% on day 3 and 2.55% on day 5 for iomeprol and 2.29% on day 3 and 1.91% on day 5 for the control.
CONCLUSION: Ionic contrast agents lead to reversible transient focal endothelial cell injury. No such side effect was detectable for non-ionic contrast agents.