Contrast nephrotoxicity: predictive value of urinary enzyme markers in a rat model.
OBJECTIVE
We tested whether urinary enzymes are an accurate and useful marker of renal damage in a rat model of contrast media nephrotoxicity.


METHODS
Thirty rats were pretreated with a combination of salt depletion, indomethacin, and contrast material. Alanine aminopeptidase (AAP), gamma-glutamyltranspeptidase (GGT), and N-acetyl-beta-D-glucosaminidase (NAG) were measured before and 24 hr after injection of contrast material. Enzyme concentrations were correlated with glomerular filtration rate (GFR) and histology.


RESULTS
Decreasing GFR and histopathologic changes were found only in rats treated with all three variables. NAG levels increased from baseline for both diatrizoate meglumine- and ioversol-treated animals (from 83.9 +/- 48.6 to 145.5 +/- 55.4 and from 69.41 +/- 43.6 to 123.1 +/- 50.7, respectively; P < 0.05 from baseline for ioversol) and declined in other groups. GGT and AAP levels did not correlate well with structural and functional changes.


CONCLUSIONS
In this model of contrast nephrotoxicity, NAG concentration appears to correlate with structural and functional changes associated with contrast media nephrotoxicity. However, the large range of baseline values makes this of dubious clinical use. AAP and GGT levels appear less helpful in detecting renal damage.
Naidu
S G
SG
Department of Radiology, University of Wisconsin Hospital and Clinics, Madison 53792-3252, USA.
Lee
F T
FT
D000118:Acetylglucosaminidase / Q000187:drug effects / Q000652:urine*; D000818:Animals; D015415:Biomarkers / Q000652:urine; D018826:CD13 Antigens / Q000187:drug effects / Q000652:urine*; D003287:Contrast Media / Q000633:toxicity*; D003404:Creatinine / Q000032:analysis; D003974:Diatrizoate Meglumine / Q000633:toxicity*; D004039:Diet, Sodium-Restricted; D004232:Diuretics / Q000008:administration & dosage; D005665:Furosemide / Q000008:administration & dosage; D007668:Kidney / Q000187:drug effects* / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014283:Triiodobenzoic Acids / Q000633:toxicity*; D005723:gamma-Glutamyltransferase / Q000187:drug effects / Q000652:urine*
D015415:Biomarkers; D003287:Contrast Media; D004232:Diuretics; D014283:Triiodobenzoic Acids; D003974:Diatrizoate Meglumine; D005665:Furosemide; D003404:Creatinine; D005723:gamma-Glutamyltransferase; D000118:Acetylglucosaminidase; D018826:CD13 Antigens; C054871:ioversol