Histamine release and contrast media-induced renal vasoconstriction

Area of Science:

• Nephrology
• Pharmacology
• Vascular Biology

Background:

• Contrast media are essential in medical imaging but can induce nephrotoxicity.
• Histamine release is a suspected contributor to contrast-induced renal vasoconstriction and subsequent kidney damage.

Purpose of the Study:

• To investigate the role of histamine release in contrast medium-induced renal vasoconstriction.
• To compare the effects of ionic and nonionic contrast media on renal arteries.
• To assess the impact of histamine H1 and H2 blockers on contrast-induced renal vasoconstriction.

Main Methods:

• Isometric contractions of rabbit renal arteries were measured.
• Arteries were stimulated with KCl, ionic (diatrizoate), and nonionic (iomeprol, iodixanol) contrast media.
• The effects of histamine H1 (diphenhydramine) and H2 (cimetidine) blockers were evaluated.
• Histamine concentrations post-contrast administration were quantified.

Main Results:

• Ionic contrast media (diatrizoate) induced significant dose-dependent renal artery contractions (27%) compared to nonionic agents (iodixanol 5%, iomeprol 4.5%).
• Diphenhydramine partially inhibited contractions (49%), while cimetidine had no effect.
• Histamine levels significantly increased only after diatrizoate administration.

Conclusions:

• Ionic contrast media trigger histamine release, leading to renal vasoconstriction, which can be partially mitigated by H1 blockers.
• Nonionic contrast media do not induce histamine release or significant renal vasospasm.
• These findings highlight potential differences in nephrotoxicity mechanisms between ionic and nonionic contrast agents.