Effects of X-ray contrast media and radiation on human vascular endothelial cells in vitro.

We have used cell culture techniques to study the effects of 16 contrast agents on human vascular endothelial cells (HUVEC) in vitro, where both the dose and duration of exposure are precisely known. Our results demonstrate that 1) exposure of HUVEC to radiographic contrast media can produce dose and time-dependent inhibition of the incorporation of [3H]leucine, [3H]thymidine, or [3H]uridine into macromolecules; 2) thymidine incorporation is the most affected; 3) the inhibition is not primarily due to osmotic effects; and 4) concomitant exposure to X-irradiation does not sensitize HUVEC to contrast agents. Where marked inhibition occurred, it was accompanied by changes in cell morphology and later, by loss of the cytoplasmic marker lactate dehydrogenase, indicating that under the conditions of our experiments the effects were cytotoxic, and not merely cytostatic.