Escherichia coli pyometra induces transient glomerular and tubular dysfunction in dogs

Abstract

Background: Pyometra in dogs has been associated with renal injury.

Hypothesis: Examine pyometra-related nephropathy by evaluating novel renal biomarkers.

Animals: Twenty-five dogs with Escherichia coli pyometra. Fourteen clinically healthy bitches of comparable age.

Methods: Prospective study. Urinary biomarkers determined by immunoassays (uIgG, uCRP, uAlb, uRBP, uTXB2) or colorimetric test (uNAG) with results normalized to urine creatinine concentration. Nonparametric Mann-Whitney U-test and Wilcoxon's signed-rank test used to compare healthy dogs and dogs with pyometra, and dogs with pyometra at initial and follow-up examination.

Results: Urinary biomarkers (median, range) significantly increased in dogs with pyometra (uIgG/Cr: 169.7 mg/g, 4.8-1052.9; uCRP/Cr: 0.260 mg/g, 0.006-3.030; uAlb/Cr: 89.5 mg/g, 8.8-832.7; uRBP/Cr: 1.66 mg/g, 0.05-21.44; uNAG/Cr: 5.8 U/g, 1.6-27.7; uTXB2 /Cr: 15.3 μg/g, 3.2-139.6) compared with healthy bitches (uIgG/Cr: 3.4 mg/g, 0.6-8.9; uCRP/Cr: below detection limit; uAlb/Cr: 17.5 mg/g, 1.3-166.3; uRBP/Cr: 0.13 mg/g, 0.02-0.44; uNAG/Cr: 2.4 U/g, 1.4-7.4; uTXB2 /Cr: 2.4 μg/g, 1.2-4.7) (P<.001). Six months after ovariohysterectomy, urinary biomarkers in pyometra group (uIgG/Cr: 4.7 mg/g, 1.5-99.8; uCRP/Cr: below detection limit; uAlb/Cr: 13.9 mg/g, 2.1-471.2; uRBP/Cr: 0.05 mg/g, 0.02-0.32; uNAG/Cr: 1.6 U/g, 0.9-3.3; uTXB2 /Cr: 3.3 μg/g, 1.0-6.9) were significantly lower than before surgery (P<.01), and not significantly different to those of healthy dogs (P>.05).

Conclusion and clinical importance: Pyometra-related renal dysfunction affects the nephron both at glomerular and proximal tubular level and is a transient process in most dogs with E. coli pyometra.