Copper hepatopathies in Australian dogs

INTRODUCTION

To evaluate hepatopathies in Australian dogs according to the World Small Animal Veterinary Association (WSAVA) guidelines. Specifically, to describe the prevalence and survival of dogs with copper-associated hepatopathy.

MATERIALS AND METHODS

Medical records from the Small Animal Specialist Hospital were reviewed to identify dogs with liver disease and liver biopsy between November 2008 and November 2021. Liver histopathology reports were reviewed with a board-certified veterinary pathologist and classified according to the WSAVA guidelines. Histopathology reports and clinical records were reviewed to ascertain the most important histological process for statistical analysis. Copper-associated hepatopathy was defined as (i) histological evidence of copper accumulation in centrilobular areas (Zone 3) associated with hepatocyte necrosis, inflammation with copper-laden macrophages and chronic hepatitis (ii) histochemical copper staining showing hepatocyte copper accumulation in the centrilobular areas and iii) hepatic copper measurement with concentrations greater than 600 μg/g dry weight of liver. Dogs with primary inflammatory parenchymal disease included dogs with copper-associated hepatopathy, idiopathic chronic hepatitis, non-specific reactive hepatitis, chronic bacterial hepatitis and immune-mediated chronic hepatitis. Descriptive statistics were performed for all dogs. Age, weight and clinicopathologic data were compared between dogs with copper-associated hepatopathy and dogs with other causes of chronic primary inflammatory parenchymal liver disease (Kruskal-Wallis test). Survival times were calculated and compared (Kaplan-Meier curves and log rank test) between dogs with copper-associated hepatopathy and dogs with other chronic primary inflammatory parenchymal liver diseases. Breed was evaluated to determine the breed most commonly affected with copper-associated hepatopathy and identify any breed in which this disease has not previously been described.

RESULTS

Sixty-seven (43 female, 24 male) dogs with a median age of 7.8 years (quartile [Q] Q1-Q3 4.5-9.6 years) were included. Thirteen dogs had copper-associated hepatopathy, eight dogs had idiopathic chronic hepatitis, eight dogs had non-specific reactive hepatitis, seven dogs had disorders associated with portal hypertension, five dogs had chronic bacterial hepatitis and four dogs had immune-mediated chronic hepatitis. Compared with dogs with other causes of chronic primary inflammatory parenchymal liver disease, dogs with copper-associated hepatopathy tended to be younger (6.73 vs. 8.01 years, P = 0.057) and heavier (19.8 vs. 9.6 kg, P = 0.052) than dogs with other causes of primary chronic inflammatory parenchymal diseases. There was no statistically significant difference when ALT (P = 0.30), ALP (P = 0.18) and total bilirubin (P = 0.13) were compared between the two groups. The median survival time for all dogs after liver biopsy was 2010 days (CI 1321 days - not reached). There was no significant difference in survival between dogs with copper-associated hepatopathy and dogs with other causes of chronic primary inflammatory parenchymal liver disease (P = 0.5).

CONCLUSIONS

Copper-associated hepatopathy was common among Australian dogs with chronic hepatopathies, occurring in younger and heavier dogs than other causes of primary inflammatory parenchymal liver disease. Clinical pathology is not useful for differentiating between copper-associated hepatopathy and other causes of chronic primary inflammatory parenchymal liver disease. When copper-associated hepatopathy is treated, the prognosis can be good. This is the first report of copper-associated hepatopathy in Australian Cavalier King Charles Spaniels.

Copper metabolism and its implications for canine nutrition

Canine copper nutrition has received increased attention due to recent reports of apparent copper-associated hepatitis in the USA and European Union. In order to properly address the need to modify the U.S. National Research Council and Association of American Feed Control Officials canine copper recommendations that will have implications for all dogs, it is important to understand the complexities of copper metabolism, confounding variables affecting copper status, and the available research on this topic in dogs. Recent trends in consumer preference for dog diets, supplements, and functional treats introduce another layer of complexity, as most ingredients used in these formulations provide vastly different proportions of essential nutrients, thus resulting in great variation in nutrient profiles available to the animal. Although controlled research addressing copper metabolism in dogs is limited, there are lessons to be learned from other monogastric species as well as canine case studies that can provide a base for increasing knowledge to address this issue. Copper metabolism and status in animals is affected by a multitude of factors including absorption, storage, excretion, and nutrient interactions. Given its vital role in many physiological processes, it is important that both nutritional deficiencies and toxicities be avoided. Additionally, another challenge for proper copper nutrition in dogs is the known genetic predispositions of some breeds for copper storage and excretion abnormalities. Therefore, it is imperative that veterinarians, nutritionists, and pet food manufacturers collaborate with the shared goal of providing dog food options that supply the essential nutrients at adequate concentrations to support an active and healthy life. Many questions remain regarding copper metabolism and proper diet formulation for dogs. Future research efforts should focus on discovering reliable, non-invasive methods for evaluating canine copper status, a deeper understanding of genetic predispositions of certain breeds, increased knowledge of copper contributions from various ingredients, and the role of unpredictable physiological stressors on copper metabolism.

Characterization of clinical presentation, histological features, ultrasonographic findings, and survival in 29 dogs with granulomatous hepatitis

BACKGROUND

Granulomatous hepatitis (GH) is a form of chronic hepatitis (CH) in dogs for which limited information is published.

HYPOTHESIS

Describe the clinical presentation, clinical pathology, ultrasound, and hepatic histopathology findings and to report survival times in dogs with GH.

ANIMALS

Twenty-nine client-owned dogs with GH.

METHODS

Retrospective observational study. Pathology records were searched. Inclusion criteria included a histopathologic diagnosis of GH, absence of an identified etiology or evidence of extrahepatic granulomatous disease, and a medical record available for review. Clinical presentation, clinical pathologic findings, treatment protocols, and survival times were recorded. Available hepatic biopsy material was graded and scored, and ultrasound evaluations reviewed.

RESULTS

The median age was 7 years (range, 0.66-12 years). Nineteen breeds were represented. Decreased appetite (19/29), lethargy (16/29), and fever (13/29) were seen most commonly. All dogs had increased serum transaminase activities, whereas 21/29 and 12/24 had hyperbilirubinemia and neutrophilia, respectively. Ultrasonographic findings included hepatomegaly (12/22), nodular parenchymal lesions (9/22), and hyperechoic parenchymal bands (8/22). Histopathologic necroinflammatory scores were moderate to severe in 16/19 dogs, and fibrosis scores were mild in 14/19 dogs. Treatments varied and included antibiotics, immunosuppressive drugs, and hepatoprotectants. Overall median survival was 635 days (range, 1-2482 days).

CONCLUSION AND CLINICAL IMPORTANCE

Granulomatous hepatitis in dogs is associated with high histopathologic grade, fever, neutrophilia, and a high incidence of hepatomegaly and focal parenchymal lesions on ultrasound examination. Despite disease severity on presentation, dogs with GH can have a good outcome with prolonged survival.

Nutritional management of a dog with hepatic enzymopathy suspected to be secondary to copper-associated hepatitis: a case report

A 4-year-old, female-spayed American Bulldog presented to the Ontario Veterinary College's Health Sciences Center's Clinical Nutrition Service for nutritional management of hepatic enzymopathy and suspected copper-associated hepatitis. Medical history revealed a 3-month history of gradually increasing serum ALT. Additional diagnostics included negative Leptospira titters, normal bile acids, and laparoscopic liver biopsy. Histopathology findings were consistent with diffuse moderate vacuole hepatocellular degeneration, mild positive copper staining, mild chronic lymphoplasmacytic hepatitis both portal and central, and mild biliary hyperplasia. Hepatic copper quantification results were above normal ranges (630 μg/g dry tissue), but below those seen in familial copper-associated hepatitis (>800-1,000 μg/g dry tissue). The patient was prescribed ursodeoxycholic acid, recommended to be fed a homemade diet (HMD), and referred for a nutrition consult. Two days before the nutrition consult, serum ALT fell within the normal range. The body condition score was 5/9, with a good muscle condition score and the dog's appetite and body weight remained stable. Energy intake was appropriate for maintenance. Key nutrient levels of all diets reported were compared to industry standards (AAFCO, NRC, and FEDIAF). Diet history included a commercially available raw meat-based diet (RMBD), of unknown copper content; a high energy commercial dry food (HEC), with copper content higher than the maximum recommended by FEDIAF and immediately prior to nutrition consult the patient had been eating an unbalanced homemade diet (HMD1) for 4 weeks. HMD1 was low in copper and deficient in the hepatoprotectant nutrients vitamin E and zinc. As per the owner's preference and to accommodate the patient's unique nutritional needs, a homemade diet addressing key nutrients for liver disease was formulated (HMD2), with copper content just above the recommended minimum. The new diet was found palatable and the patient's body weight, body, and muscle condition scores remained unchanged. Two months after starting HMD2, all bloodwork values remained within the normal range, including ALT. The reduction of dietary copper content likely reduced serum ALT. However, unbalanced diets cause a risk of nutrient deficiencies and excess. This dog was maintained with no known adverse effects on a complete and balanced HMD diet with a moderately low copper content, moderate protein, and inclusion of hepatoprotective nutrients.

Copper toxicosis in Bedlington terriers is associated with multiple independent genetic variants

BACKGROUND

Bedlington terrier copper toxicosis (CT) is due to a homozygous exon deletion in COMMD1. CT also occurs in Bedlingtons lacking this deletion. An association with two ABCA12 single nuceotide polymorphism (SNP) splice variants was reported. Labrador retriever CT is associated with a missense mutation in ATP7B, and with a protective mutation in ATP7A.

METHODS

Liver and DNA samples from 24 affected and 10 unaffected Bedlingtons were assessed for copper and genetic variants. Allelic frequencies were compared. The ATP7B mutation frequency was investigated in 144 dogs of other breeds.

RESULTS

The ABCA12 SNPs showed no differences between groups. The COMMD1 deletion was less frequent in unaffected than in affected dogs and in affected dogs post-2001 than pre-2001. The ATP7B mutation was more frequent in affected than unaffected Bedlingtons. Thirty-five of 144 dogs of other breeds were homo- or heterozygous for the ATP7B mutation. The ATP7A mutation was absent from Bedlingtons.

LIMITATIONS

Clinical information and qualitative copper measurements were unavailable for most dogs.

CONCLUSION

The COMMD1 deletion remains present in Bedlington terriers but is no longer the primary cause of CT. ABCA12 SNPs were not associated with CT. The ATP7B:c.4358G>A mutation was significantly associated with Bedlington CT and was more common in dogs of this breed than in the 144 dogs of other breeds.

Quantitative bioimaging of copper in frozen liver specimens from cats using laser ablation-inductively coupled plasma-mass spectrometry

OBJECTIVES

The aim of this study was to assess laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) as a tool for measuring concentrations and determining accumulation of copper in frozen liver specimens from cats.

METHODS

Six frozen liver specimens were evaluated by qualitative copper staining and quantitative flame atomic absorption spectroscopy. Tissue specimens were cryo-sectioned and quantitative bioimaging of copper was performed using LA-ICP-MS. Results were compared with those obtained using conventional methods.

RESULTS

Of the six specimens, only one showed positive staining for copper with rhodanine. Using flame atomic absorption spectroscopy (FAAS), one specimen showed a deficient copper level (<100 µg/g dry weight), two specimens had copper within the reference interval (RI; 150-180 µg/g) and three specimens had copper concentrations above the RI. Bioimaging from LA-ICP-MS showed inhomogeneous distribution of hepatic copper. The areas with dense copper accumulation were represented as hotspots in the liver specimens. Hepatic copper quantification by LA-ICP-MS correlated well with copper quantified by FAAS (r = 0.96, P = 0.002).

CONCLUSIONS AND RELEVANCE

Our findings suggest that quantitative bioimaging by LA-ICP-MS could be used to demonstrate the distribution and concentration of copper in frozen liver specimens from cats. The distribution of copper in these specimens was inhomogeneous with dense accumulation represented as hotspots on tissue sections. A positive correlation of hepatic copper concentrations determined by LA-ICP-MS and FAAS was found. Further studies to establish an RI for hepatic copper using this technique and to further determine its clinical utility are warranted.

Mineral and heavy metal content in dry dog foods with different main animal components

Dog caregivers, mainly for economic reasons and easy availability, choose dry, over the counter diets (OTC). The mineral composition of OTC foods depends primarily on the components used in the production of the pet food. Regardless of the main component of the food, it must meet the recommended minimum mineral content, established by nutritional guidelines. Therefore, the aim of this study was to determine the mineral (Ca, K, Mg, Na, Fe, Mn, Zn, Cu, Mo) and heavy metal content (Pb, Co, Cd, Cr, Ni) using the methods of colorimetry and mass spectrometry, of OTC dry dog foods and to compare with the FEDIAF and AAFCO nutritional guidelines. Dry foods pose no risk to dogs in terms of heavy metal content. The worst results in terms of mineral content were obtained in mixed foods, therefore it is worth considering feeding the dog a mono-protein food. The PCA analysis disproved our hypothesis and revealed that the main animal source did not statistically significantly affect the levels of minerals and their ratios. However, the analysis of contrasts confirms the differentiation of the content of individual minerals between the groups of foods. For the first time, we proved that pet food with a mineral composition similar to the MIN-RL may be characterized by unfavorable mineral ratios.

From Nutritional Adequacy to Hygiene Quality: A Detailed Assessment of Commercial Raw Pet-Food for Dogs and Cats

Raw meat-based diets (RMBDs) are widely used as unconventional diets for dogs and cats at different life stages, despite concerns regarding nutritional adequacy and microbial contamination. The aim of this study was to evaluate both the nutritional and hygiene quality profile of RMBDs purchased in Germany. For this purpose, crude nutrients were assessed in 44 RMBDs and compared to declared values. In addition, selected minerals were determined in 31 RMBDs labelled as complete and compared to the minimum requirement (MR) for intended species and life stages. Aerobic colony count (ACC) and Enterobacteriaceae were used to assess the hygiene quality of 37 commercial RMBDs, while the presence of Salmonella spp. was examined in 10 products. Fat and protein content exceeded tolerated deviation from declared values in 33% and 45% of RMBDs, respectively. Each RMBD showed at least one concern regarding nutrient content. The RMBDs had high fat contents (mean 69, range 33−95 g/Mcal) that were negatively correlated with protein (r = −0.74, p < 0.0001). Considerable contaminations by ACC and Enterobacteriaceae were found (2.61 × 108 ± 3.63 × 108 and 3.61 × 106 ± 8.39 x106 CFU/g, respectively). A higher count of Enterobacteriaceae was detected in a frozen RMBDs made of poultry or carcasses from different animals, compared to the thawed counterpart (p = 0.003), as well as compared to other sources, such as beef, horse, and lamb, regardless of the storage condition. Salmonella spp. were found in 2/10 RMBDs. This study confirmed that feeding commercial RMBDs might pose a risk to pet health.

ATP7A, ATP7B, and RETN genotypes in Labrador Retrievers with and without copper-associated hepatopathy

OBJECTIVE

To determine the frequency of previously reported coding variants in the ATP7A, ATP7B, and RETN genes in a US population of Labrador Retrievers and to explore potential associations of these genotypes with pathologic hepatic copper accumulation.

SAMPLE

Archived hepatic specimens from 90 Labrador Retrievers collected between 2013 and 2021.

PROCEDURES

The Michigan State University Veterinary Diagnostic Laboratory database was searched to identify archived tissues from Labrador Retrievers that had undergone hepatic histopathologic assessment. Cases were classified into control, copper-associated hepatopathy (CAH), and intermediate populations on the basis of histopathologic features and hepatic copper accumulation. The DNA was extracted from archived tissues and genotyped for reported variants in the 3 genes. Allele frequencies were determined, and associations of genotypes with CAH status were evaluated.

RESULTS

29 control dogs, 45 CAH dogs, and 16 intermediate dogs were included in the study. The overall ATP7A and RETN variant allele frequencies were 30% and 13%, respectively, and were not significantly different among control, CAH, and intermediate populations. The ATP7B variant allele frequency was significantly higher in the CAH population (30%) as compared to the control population (13%). However, 21 of 45 (47%) CAH dogs did not have an ATP7B variant allele whereas 7 of 28 (25%) control dogs did have an ATP7B variant allele.

CLINICAL RELEVANCE

Study results supported a contributory role for the ATP7B variant in CAH pathogenesis in Labrador Retrievers. However, the application of genetic testing in a clinical setting is complicated by genotypic variability within healthy and diseased dogs.

Hepatic copper accumulates in ferrets with and without hepatobiliary disease

OBJECTIVE

To determine hepatic copper concentrations and zonal distribution in ferrets with and without hepatobiliary disease, validate rhodanine-based qualitative copper scoring and digital copper quantification in ferret hepatic samples, and ascertain whether clinical features predicted copper accumulation.

ANIMALS

34 ferrets, including 7 with necroinflammatory disease, 5 with hepatocellular carcinoma, 13 with non-necroinflammatory disease, and 9 with no hepatobiliary disease.

PROCEDURES

Rhodanine-based digital copper quantification was validated by use of liver dually measured by atomic absorption spectroscopy and digital scanning (R2 = 0.98). Clinical features and hepatic copper scores and concentrations (dry weight liver) were compared between groups. Zonal copper distribution was determined.

RESULTS

Hepatic copper concentration was strongly correlated with copper scores (ρ = 0.88). Ferrets with hepatobiliary disease were significantly older and had significantly higher serum alkaline phosphatase and γ-glutamyltransferase activities and creatinine concentrations. Centrilobular copper accumulated in 23 of 34 (64%) ferrets with (n = 15) and without (8) hepatobiliary disease. Median copper concentrations were not significantly different between ferrets with and without hepatobiliary disease but were significantly higher within neoplastic hepatic tissue in ferrets with hepatocellular carcinoma. Hepatic copper concentrations exceeded feline (> 180 µg/g) and canine (> 400 µg/g) reference limits in 19 and 9 ferrets, respectively. Hepatic copper > 1,000 µg/g occurred in 5 ferrets with and 2 without hepatobiliary disease. Clinical features did not predict copper accumulation.

CLINICAL RELEVANCE

Rhodanine-based digital copper quantification and qualitative copper scoring discerned liver copper accumulation in ferrets. Ferrets with and without hepatobiliary disease displayed a propensity for centrilobular hepatic copper accumulation of uncertain clinical importance. Clinical and clinicopathologic features could not exclusively implicate pathologic copper accumulation.

Copper Toxicity in Horses: Does it Exist?

Copper toxicity is thought to be a rare condition in horses. However, the number of cases diagnosed in Brazil is growing. This article aims to describe cases of copper toxicity involving horses from different geographic locations and discuss findings of physical examinations, differential diagnoses and potential causes. Five cases referred from 4 different properties where at least 15 other horses were affected were described. Hemolytic anemia and hemoglobinuria, presence of Heinz bodies and elevated aspartate aminotransferase and gamaglutamil transferase levels were detected in all cases. The diagnosis was based on clinical history and signs, laboratory tests results, copper level determination in feed and/or soil and histopathological findings. Two horses progressed to acute death; remaining horses responded to clinical management with or without blood transfusion, depending on disease severity. However, one of these horses, after several returns to the veterinary hospital, was euthanized due to complications. One horse was treated with ammonium tetrathiomolybdate. Two horses had several recurring episodes over the course of several months, an uncommon presentation in ruminants suffering from copper toxicity. Excess copper was associated with soil fertilization with poultry litter or treatment of previous or neighbor crops with copper-containing products. It can be concluded that copper toxicity does occur in horses and may arise from several sources and/or be associated with predisposing dietary factors. Given the growing number of cases, the condition should be included in the differential diagnosis list and proper preventive dietary and pasture fertilization measures adopted.