Radiographic
contrast agent-induced
acute renal failure is an increasingly recognized clinical event. Multiple factors have been implicated in its development. Recent experiments have demonstrated that
sodium diatrizoate, a common ionic
radiocontrast agent, is moderately toxic to proximal tubule cells in vitro, and that this toxicity is enhanced by
hypoxia. In this study, we compare toxicities of the nonionic
radiocontrast agent,
iopamidol, and the commonly used ionic
contrast agent,
diatrizoate.
Suspensions enriched in proximal tubule segments were exposed for 82.5 min to 10 or 25 mM
diatrizoate or 10 or 25 mM
iopamidol with or without 22.5 min or 30 min of
hypoxia. Cell viability parameters, including basal and uncoupled respiratory rates, tubule cell
potassium and
calcium levels and cell
ATP content were measured. No consistent differences in tubule viability parameters were observed between tubule
suspensions exposed to 10 mM concentrations of the
radiocontrast agents during either oxygenated or hypoxic conditions. Under oxygenated conditions, both 25 mM
iopamidol and
diatrizoate exposure produced greater metabolic alterations in renal tubules than control conditions, but the effects were not statistically significant. With concomitant
hypoxia, the alterations after 25 mM
diatrizoate exposure were significantly greater than those seen after exposure to 25 mM
iopamidol.
Iopamidol had less of a detrimental effect on renal tubule
potassium content and both basal and uncoupled respiratory rates than that of
diatrizoate under these conditions. Thus,
diatrizoate is more toxic to rabbit renal proximal tubule cells than
iopamidol in vitro, and this difference in toxicity is enhanced by
hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)