Internal Medicine Staff Veterinarian University of California, Davis Davis, CA, United States
Abstract:
Background: Urinary copper:zinc ratios (Cu:Zn) could be a valuable biomarker of copper-associated chronic hepatitis (CAH).
Objectives: Compare urinary Cu:Zn between: 1) CAH, immune-mediated chronic hepatitis (ICH), and healthy control dogs 2) pre and post-treatment in dogs with CAHAnimals: 18 dogs with CAH, 18 dogs with ICH, 11 healthy controls
Methods: Urinary Cu and Zn were measured prospectively using flame atomic absorption spectroscopy. Dogs with CAH had hepatic copper ≥ 1500 ppm, copper pigment granulomas, and minimal to no interface hepatitis. Dogs with ICH had interface hepatitis. Dogs with CAH were treated with D-penicillamine (10-15mg/kg PO q12) and a copper-restricted diet for 6 months and re-biopsied. Wilcoxon rank sum test compared Cu:Zn between ICH, CAH, and healthy controls at diagnosis. Wilcoxon signed rank test compared Cu:Zn pre- and post-treatment in dogs with CAH. A Spearman’s correlation examined the relationship between Cu:Zn and hepatic copper in dogs treated for CAH.
Results: Urinary Cu:Zn was higher at diagnosis of CAH and ICH compared to healthy dogs (p = 0.002), but no different between CAH and ICH (p = 0.40). Urinary Cu:Zn post-treatment of CAH was significantly lower compared to pre-treatment (p = 0.01) and no different to healthy dogs (p = 0.5), but did not correlate with hepatic copper post-treatment (p = 0.29, r2 = 0.32). Conclusions and Clinical Importance: Urinary Cu:Zn did not differentiate between CAH and ICH, but ratios significantly lowered during treatment of CAH. Urinary Cu:Zn could be a useful marker to monitor treatment response in dogs with CAH.
