Hepatic copper concentrations in 546 dogs (1982–2015)

BACKGROUND: Copper associated hepatitis (CAH) has been increasingly recognized in dogs, and speculation exists that hereditary defects in copper metabolism have been exacerbated by increased environmental copper exposure. However, no broad epidemiological investigations have been performed to investigate quantitative hepatic copper concentrations ([Cu](H)) over time in both dogs that are (predisposed breed [PB]), and are not (non‐predisposed breed [NPB]), considered at‐risk for CAH. OBJECTIVES: To investigate [Cu](H) in dogs and explore temporal, demographic, and histologic associations spanning 34 years. ANIMALS: 546 archived liver specimens. METHODS: Retrospective study. Searches of the Michigan State University Veterinary Diagnostic Laboratory database identified dogs that had undergone hepatic histopathologic assessment. Cases with archived tissue were reviewed and classified by breed, time period, and presence or absence of hepatitis. Inductively coupled plasma mass spectrometry was used to determine [Cu](H). RESULTS: In time period 2009–2015, median [Cu](H) were 101 μg/g and 313 μg/g greater than median [Cu](H) in time period 1982–1988 for NPB and PB dogs, respectively (P < .001 for both comparisons). The proportion of dogs with [CU](H) > 300 μg/g increased in NPB (28% to 49%) and PB dogs (48% to 71%) during these periods (P = .002 for both comparisons). Median [Cu](H) in dogs with hepatitis increased 3‐fold over time in both NPB (P = .004) and PB populations (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: The frequent recognition of CAH in recent years is likely due to the observed increases in [Cu](H) over time. Importantly, effects are not limited to PB dogs.