Contrast agents and renal cell apoptosis.
OBJECTIVE
Contrast media (CM) induce a direct toxic effect on renal tubular cells. This toxic effect may have a role in the pathophysiology of contrast nephropathy.


RESULTS
We evaluated (i) the cytotoxicity of CM [both low-osmolality (LOCM) and iso-osmolality (IOCM)], of iodine alone, and of an hyperosmolar solution (mannitol 8%) on human embryonic kidney (HEK 293), porcine proximal renal tubular (LLC-PK1), and canine Madin-Darby distal tubular renal (MDCK) cells; and (ii) the effectiveness of various antioxidant compounds [n-acetylcysteine (NAC), ascorbic acid and sodium bicarbonate] in preventing CM cytotoxicity. The cytotoxicity of CM was assessed at different time points, with different methods: cell viability, DNA laddering, flow cytometry, and caspase activation. Both LOCM and IOCM produced a concentration- and time-dependent increase in cell death as assessed by the different methods. On the contrary, iodine alone and hyperosmolar solution did not induce any significant cytotoxic effect. There was not any significant difference in the cytotoxic effect between LOCM and IOCM. Furthermore, both LOCM and IOCM caused a marked increase in caspase-3 and -9 activities and poly(ADP-ribose) fragmentation, while no effect on caspase-8/-10 was observed, thus indicating that the CM activated apoptosis mainly through the intrinsic pathway. Both CM induced an increase in protein expression levels of pro-apoptotic members of the Bcl2 family (Bim and Bad). NAC and ascorbic acid but not sodium bicarbonate had a dose-dependent protective effect on renal cells after 3 h incubation with high dose (200 mg iodine/mL) of both LOCM and IOCM.


CONCLUSIONS
Both LOCM and IOCM induce a dose-dependent renal cell apoptosis. NAC and ascorbic acid but not sodium bicarbonate prevent this contrast-induced apoptosis.
Romano
Giulia
G
Department of Cellular and Molecular Biology and Pathology, Federico II University of Naples, Naples, Italy.
Briguori
Carlo
C
Quintavalle
Cristina
C
Zanca
Ciro
C
Rivera
Natalia V
NV
Colombo
Antonio
A
Condorelli
Gerolama
G
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000008:administration & dosage; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D003287:Contrast Media / Q000009:adverse effects*; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007472:Iohexol / Q000009:adverse effects / Q000031:analogs & derivatives*; D007684:Kidney Tubules / Q000187:drug effects* / Q000378:metabolism; D009994:Osmolar Concentration; D013552:Swine; D014283:Triiodobenzoic Acids / Q000009:adverse effects*
D003287:Contrast Media; D014283:Triiodobenzoic Acids; C093233:iobitridol; D007472:Iohexol; D020169:Caspases; C044834:iodixanol; D001205:Ascorbic Acid