Managing copper-related liver disease in Labrador retrievers with diet

Abstract

Canine hereditary copper-associated hepatitis is characterized by gradual hepatic copper accumulation eventually leading to liver cirrhosis. Therapy is aimed at creating a negative copper balance with metal chelators, of which D-penicillamine is the most commonly used. D-penicillamine often causes gastro-intestinal side effects and life-long continuous therapy may lead to a deficiency of copper and zinc. The aim of the current study was to investigate the effect of a low-copper, high-zinc diet as an alternative to continuous D-penicillamine treatment for the long-term management of canine copper-associated hepatitis. Sixteen affected Labrador retrievers were followed for a median time period of 19.1 months (range, 5.9-39 months) after being effectively treated with D-penicillamine. The dogs were maintained on a diet containing 1.3±0.3 mg copper/1000 kcal and 64.3±5.9 mg zinc/1000 kcal. Liver biopsies were taken every 6 months for histological evaluation and copper determination. Plasma alanine aminotransferase (ALT) and alkaline phosphatase, as well as serum albumin were determined. Dietary treatment alone was sufficient to maintain hepatic copper concentration below 800 mg/kg dry weight liver in 12 dogs during the study period. Four dogs needed re-treatment with D-penicillamine. ALT activity and albumin concentration were not associated with hepatic copper concentration, but showed a significant association with the stage and grade of hepatitis respectively. In conclusion, a low-copper, high-zinc diet can be a valuable alternative to continuous d-penicillamine administration for long-term management of dogs with copper-associated hepatitis. The copper re-accumulation rate of an individual dog should be considered in the design of a long-term management protocol and in determining re-biopsy intervals.