Kidney injury molecule-1 and urinary gamma-glutamyl transferase as biomarkers of acute kidney injury in cats.

Abstract

To evaluate the concentration of kidney injury molecule-1 and activity of urinary gamma-glutamyl transferase in cats with urethral obstruction and healthy cats. Blood and urine samples were collected from a group of 15 healthy cats (control group) and a group of 20 cats with urethral obstruction at presentation, and 24hours and 7 days after unblocking the obstruction. The serum creatinine, urinary creatinine and urinary gamma-glutamyl transferase were measured by spectrophotometry and kidney injury molecule-1 by the sandwich enzyme-linked immunosorbent assay. On presentation, cats with obstruction had serum creatinine concentration and urinary gamma-glutamyl transferase index higher than healthy cats (mean difference 544 μmol/L, 95% confidence intervals 222 to 865 μmol/L, and 0.0022 U/μmol-uCre, 0.00043 to 0.0039 U/μmol-uCre, respectively), urine creatinine concentration lower (mean difference 25,624 µmol/L, 17,329 to 33,919 µmol/L), and no significant difference in the kidney injury molecule-1/urinary creatinine ratio (mean difference 13 pg/μmol-uCre, -33 to 59 pg/μmol-uCre). In the group of cats with urinary obstruction, over time serum creatinine decreased, urine creatinine increased, urinary gamma-glutamyl transferase index did not change significantly, and kidney injury molecule-1/urinary creatinine ratio increased. Cats with post-renal obstruction and potential intrinsic renal damage had higher urinary gamma-glutamyl transferase index than healthy cats at the time of presentation and showed increase in kidney injury molecule-1/urinary creatinine ratio over time.