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, uTXB 2 ) 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; uTXB 2 /Cr: 15.3 mg/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; uTXB 2 /Cr: 2.4 mg/g, 1.2-4.7) (P o .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; uTXB 2 /Cr: 3.3 mg/g, 1.0-6.9) were significantly lower than before surgery (P o .01), and not significantly different to those of healthy dogs (P 4 .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.

Correlation of Urine and Serum Biomarkers with Renal Damage and Survival in Dogs with Naturally Occurring Proteinuric Chronic Kidney Disease

“…Urine immunoglobulin G (uIgG) and urine retinol binding protein (uRBP) were increased in dogs with primary CKD7 and those with renal dysfunction secondary to various systemic diseases including pyometra, babesiosis, and snake envenomation 7, 8, 9, 10, 11, 12, 13, 14, 15. Urine, plasma, and serum neutrophil gelatinase‐associated lipocalin (NGAL) and urine N‐acetyl‐β‐D‐glucosaminidase (uNAG), a renal tubular enzyme, are tubular markers increased in both acute and CKD in dogs 7, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22. Neutrophil gelatinase‐associated lipocalin originates not only in the renal tubules but also from neutrophil granules and many other organs 23.…”

Ultrassonografia Doppler na avaliação renal de cadelas diagnosticadas com piometra antes e após tratamento com ovariosalpingohisterectomia

“…Segundo Maddens et al (2010), 12% das cadelas com piometra apresentam proteinúria persistente após a cirurgia. Neste estudo, a relação proteína/creatinina estava aumentada em 63% das cadelas no momento 1 e se manteve em 10% das cadelas no momento 2.…”

“…A dilatação de pelve pode ser decorrente de pielonefrite, já que causas obstrutivas foram descartadas (Espada et al 2006). Além disso, existem fatores de virulência da Escherichia coli, principal agente etiológico das cadelas com piometra, que predispõe a pielonefrite (Siqueira et al 2009, Maddens et al 2010). As áreas de infarto podem estar relacionadas à baixa perfusão renal, enquanto os pontos hiperecogênicos pode se referir a fibrose intersticial, achado comum no exame histopatoló-gico dos rins de cadelas com piometra (Heiene et al 2007, Maddens et al 2011.…”

<b>Caracterização da anemia em cadelas com piometra</b>

“…A estimulação crônica do sistema imune por excesso de antígeno de Escherichia coli do útero infectado pode induzir a formação de imunocomplexos circulantes, predispondo a precipitação no glomérulo, e consequente disfunção glomerular e tubular em cães (MADDENS et al, 2010). Da mesma forma, pode ocorrer a deposição na superfície das hemácias, justificando-se a maior frequência de hemácias marcadas com anti-IgG FITC no momento pré-cirúrgico.…”