Effect of contrast media on vascular smooth muscle cells

Abstract

Purpose: In order to alleviate the adverse effects of contrast media (CMs) on the vascular system, the role of Ca2+ in the viability of vascular smooth muscle cells (VSMCs) was investigated. Material and Methods: VSMCs were obtained from swine thoracic aorta. The number of VSMCs was counted under a microscope using the trypan blue dye‐exclusion method 24 h after culture in RPMI containing physiological saline (SAL) as control, iothalamate (IOT), or iohexol (IOH) at 10% by volume with CaCl2 added at 0 to 2.0 mmol/l. Free Ca2+ in the above media was measured using an ion‐selective electrode. Results: Free Ca2+ was 0.4 to 1.5 mmol/l with ionic IOT and 0.4 to 1.8 mmol/l with non‐ionic IOH as well as with control. The ratio of viable cells grown in the presence of CMs to those grown in the control was optimal at approximately 0.60 near 1 mmol/l Ca2+ and decreased markedly to 0.00 at 1.5 mmol/l Ca2+ in the presence of IOT and to 0.39 at 1.8 mmol/l Ca2+ in the presence of IOH, while the ratios decreased gradually to 0.28 in the presence of IOT and 0.53 in the presence of IOH at 0.4 mmol/l Ca2+. Conclusion: Ionic IOT is more cytotoxic to VSMCs than non‐ionic IOH. However, the cytotoxicity was minimal and similar between both CMs at 1 mmol/l Ca2+ in accordance with the sodium‐calcium balance.