Imputation of canine genotype array data using 365 whole-genome sequences improves power of genome-wide association studies.

Genomic resources for the domestic dog have improved with the widespread adoption of a 173k SNP array platform and updated reference genome. SNP arrays of this density are sufficient for detecting genetic associations within breeds but are underpowered for finding associations across multiple breeds or in mixed-breed dogs, where linkage disequilibrium rapidly decays between markers, even though such studies would hold particular promise for mapping complex diseases and traits. Here we introduce an imputation reference panel, consisting of 365 diverse, whole-genome sequenced dogs and wolves, which increases the number of markers that can be queried in genome-wide association studies approximately 130-fold. Using previously genotyped dogs, we show the utility of this reference panel in identifying potentially novel associations, including a locus on CFA20 significantly associated with cranial cruciate ligament disease, and fine-mapping for canine body size and blood phenotypes, even when causal loci are not in strong linkage disequilibrium with any single array marker. This reference panel resource will improve future genome-wide association studies for canine complex diseases and other phenotypes.

Mineralocorticoid before glucocorticoid deficiency in a dog with primary hypoadrenocorticism and hypothyroidism.

A dog with an unexpected presentation of primary hypoadrenocorticism was evaluated for clinical signs and electrolyte abnormalities characteristic of Addison's disease. Although the initial adrenocorticotropic hormone (ACTH) stimulation test documented serum cortisol concentrations within the reference range, subsequent assessments confirmed hypoaldosteronism. Mineralocorticoid replacement promptly normalized electrolytes and transiently improved clinical illness. Six weeks after initial ACTH stimulation testing, the dog became glucocorticoid deficient. Concurrent primary hypothyroidism was also documented. Hypoaldosteronism preceding hypocortisolemia is a unique presentation of canine Addison's disease.

Untargeted metabolomic profiles reveal widespread metabolic perturbations and identify candidate biomarkers in aminoaciduric canine hypoaminoacidemic hepatopathy syndrome.

OBJECTIVE: To identify metabolites and metabolic pathways affected in dogs with aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES) compared to healthy control (CON) dogs of similar ages and breeds. To improve our understanding of ACHES pathophysiology and identify novel candidate biomarkers associated with ACHES. ANIMALS: A prospective case-control study. Privately owned dogs with ACHES (n = 19) and healthy (CON) dogs (n = 9) were recruited between February 18, 2015, and April 18, 2018. METHODS: A prospective case-control study. Plasma and urine were collected from ACHES and CON dogs. The Cornell University Proteomics and Metabolomics Core Facility conducted an untargeted metabolomic analysis. RESULTS: After controlling for age, sex, and weight, 111 plasma and 207 urine metabolites significantly differed between ACHES and CON dogs. Data reduction and cluster analysis revealed robust segregation between ACHES and CON dogs. Enrichment analysis of significant compounds in plasma or urine identified altered metabolic pathways, including those related to AA metabolism, cellular energetics, and lipid metabolism. Biomarker analysis identified metabolites that best-distinguished ACHES from CON dogs, including pyruvic acid isomer and glycerol-3-phosphate in the plasma and an alanine isomer and choline in the urine. CLINICAL RELEVANCE: Our findings provide an in-depth analysis of metabolic perturbations associated with ACHES. Several affected metabolic pathways (eg, lipid metabolism) offer a new understanding of ACHES pathophysiology. Novel candidate biomarkers warrant further evaluation to determine their potential to aid in ACHES diagnosis, prognosis, and treatment monitoring.

Clinical features and amino acid profiles of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy.

BACKGROUND: Superficial necrolytic dermatitis (SND), hepatocutaneous-associated hepatopathy (HCH), aminoaciduria, and hypoaminoacidemia define hepatocutaneous syndrome (HCS) in dogs. Dogs without SND but that possess all other syndrome components are not well described. HYPOTHESIS/OBJECTIVES: To define an inclusive syndrome, aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES) for dogs with HCH or HCS. Compare clinical features, salient clinicopathologic variables, and plasma and urine amino acid (AA) profiles among ACHES cases by skin lesion status. ANIMALS: Dogs of various breeds and ages diagnosed with ACHES (n = 41). A control (CON) cohort (n = 12) provided AA profile data. METHODS: Retrospective case series. Available medical records of previously identified cases were reviewed for salient clinical features and clinical pathology data. Plasma and urine AA profiles were performed. Cutaneous lesion status was classified as none, mild, or fulminant. RESULTS: Thirty cases (73%) developed SND at some time. Dogs with fulminant skin lesions at diagnosis (n = 22/41, 54%) had significantly lower hematocrit (P = .05) and mean corpuscular volume (P = .01) than dogs without SND. Principal component analysis of plasma AA profiles identified distinct clustering of CON from ACHES dogs, but not by skin lesion status. Plasma 1-methylhistidine (<7 nmol/mL) and cystathionine (<7.5 nmol/mL) were robust ACHES biomarkers. Urine lysine (>344 nmol/mg creatinine) and methionine (>68 nmol/mg creatinine) also were useful ACHES biomarkers. CONCLUSIONS AND CLINICAL IMPORTANCE: Specific AA biomarkers provide additional diagnostic utility in ACHES. Data suggests that HCH is an early stage, and SND a later stage manifestation of ACHES.

Treatment and outcomes of dogs with hepatocutaneous syndrome or hepatocutaneous-associated hepatopathy.

BACKGROUND: Superficial necrolytic dermatitis (SND) in dogs is a rare disorder most commonly associated with hepatocutaneous syndrome. Although often reported as fatal, sporadically reported long-term remissions might be more common than previously believed and linked to treatment regimens. HYPOTHESIS/OBJECTIVES: Evaluate treatments and associated outcomes in dogs with hepatocutaneous-associated hepatopathy (HCH) with or without SND, designated collectively aminoaciduric canine hypoaminoacidemic hepatopathy syndrome (ACHES). ANIMALS: Forty-one dogs of various breeds and ages diagnosed with ACHES. METHODS: Retrospective study. Electronic surveys, medical records (2014-2019), and communication with veterinarians provided data. Three treatment categories were each dichotomized: IV amino acid (IV-AA) infusions (≥2 vs <2), supplements including S-adenosylmethionine (SAMe), arginine with ornithine, glutathione, lysine, proline, omega-3 fatty acids, or zinc (≥3 vs <3), and diet type (home-cooked vs commercial). Optimal treatment was defined as receiving ≥2 IV-AA treatments, ≥3 nutritional supplements, and a home-cooked diet. RESULTS: Most dogs (29/41, 71%) received IV-AA infusions (23/29, ≥2 infusions). Twenty-one dogs (51%) were fed commercial diets; 17/41 (41%) were fed home-cooked diets. Most dogs received SAMe (32/41, 78%) and a median of 3 supplements. In 4 dogs, HCH remission occurred. Overall all-cause median survival time (MST) was 359 days, and disease-specific MST was 557 days (range, 1-1783 days). Optimally treated dogs (n = 9) lived significantly longer (MST, >1783 days, P = .02) than variably treated dogs (MST, 214 days). CONCLUSIONS AND CLINICAL IMPORTANCE: Optimized ACHES management can resolve SND and HCH and confer long-term survival.

Clinical features, concurrent disorders, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome.

OBJECTIVE: To characterize clinical features, comorbidities, frequency of bacterial isolation, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS). ANIMALS: 168 client-owned cats with S-CCHS. PROCEDURES: Data were prospectively (1980 to 2019) collected regarding clinical features, comorbidities, bacterial infection, illness duration, and treatments. Variables were evaluated for associations with survival time. RESULTS: Median age of cats was 10.0 years, with no breed or sex predilection observed. Common clinical features included hyporexia (82%), hyperbilirubinemia (80%), lethargy (80%), vomiting (80%), jaundice (67%), weight loss (54%), and hypoalbuminemia (50%). Comorbidities included extrahepatic bile duct obstruction (53%), cholelithiasis (42%), cholecystitis (40%), and ductal plate malformation (44%) as well as biopsy-confirmed inflammatory bowel disease (60/68 [88%]) and pancreatitis (41/44 [93%]). Bacterial cultures were commonly positive (69%) despite prebiopsy antimicrobial administration in most cats. Of surgically confirmed choleliths, diagnostic imaging identified only 58%. Among 55 cats with "idiopathic pancreatitis," 28 (51%) were documented to have transiting choleliths, and 20 had pancreatic biopsies confirming pancreatitis. Cholelithiasis (with or without bile duct obstruction) and cholecystectomy were associated with survival advantages. Survival disadvantages were found for leukocytosis, ≥ 2-fold increased alkaline phosphatase, and hyperbilirubinemia. Cholecystoenterostomy had no survival impact. Cats with ductal plate malformations were significantly younger at diagnosis and death than other cats. Chronic treatments with antimicrobials, S-adenosylmethionine, and ursodeoxycholic acid were common postbiopsy. CLINICAL RELEVANCE: S-CCHS in cats was associated with bacterial infection and various comorbidities and may be confused with pancreatitis. Surgically correctable morbidities (ie, cholecystitis, cholecystocholelithiasis) and cholecystectomy provided a significant survival advantage.

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.

Bacterial culture and immunohistochemical detection of bacteria and endotoxin in cats with suppurative cholangitis-cholangiohepatitis syndrome.

OBJECTIVE: To characterize the frequency and type of bacterial infection by culture- and immunohistochemical (IHC)-based methods and determine the impact of infection on clinical features and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS). ANIMALS: 168 client-owned cats with S-CCHS (cases). PROCEDURES: Clinical features, bacterial culture results, culture-inoculate sources, and survival details were recorded. Cases were subcategorized by comorbidity (extrahepatic bile duct obstruction, cholelithiasis, cholecystitis, ductal plate malformation, biopsy-confirmed inflammatory bowel disease, and biopsy-confirmed pancreatitis) or treatment by cholecystectomy or cholecystoenterostomy. Culture results, bacterial isolates, Gram-stain characteristics, and IHC staining were compared among comorbidities. Lipoteichoic acid IHC staining detected gram-positive bacterial cell wall components, and toll-like receptor expression IHC reflected pathologic endotoxin (gram-negative bacteria) exposure. RESULTS: Clinical features were similar among cases except for more frequent abdominal pain and lethargy in cats with positive culture results and pyrexia, abdominal pain, and hepatomegaly for cats with polymicrobial infections. Bacteria were cultured in 93 of 135 (69%) cats, with common isolates including Enterococcus spp and Escherichia coli. IHC staining was positive in 142 of 151 (94%) cats (lipoteichoic acid, 107/142 [75%]; toll-like receptor 4, 99/142 [70%]). With in-parallel interpretation of culture and IHC-based bacterial detection, 154 of 166 (93%) cats had bacterial infections (gram-positive, 118/154 [77%]; gram-negative, 111/154 [72%]; polymicrobial, 79/154 [51%]). Greater frequency of bacterial isolation occurred with combined tissue, bile, and crushed cholelith inoculates. Infection and gram-positive bacterial isolates were associated with significantly shorter long-term survival times. CLINICAL RELEVANCE: S-CCHS was associated with bacterial infection, pathologic endotoxin exposure, and frequent polymicrobial infection in cats. Combined tissue inoculates improved culture detection of associated bacteria.

Disparities in hepatic copper concentrations determined by atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, and digital image analysis of rhodanine-stained sections in dogs.

OBJECTIVE: To investigate disparities in hepatic copper concentrations determined by atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and digital image analysis of rhodanine-stained sections. ANIMALS: 516 dogs. PROCEDURES: Medical records of dogs for which hepatic biopsy specimens had been submitted between January 1999 and December 2019 for evaluation of copper content were reviewed. Paired hepatic copper concentrations obtained with digital image analysis and AAS or ICP-MS were compared, and Spearman rank correlation coefficients were calculated to test for correlations between qualitative copper accumulation scores and hepatic copper concentrations. For dogs for which ≥ 4 rhodanine-stained hepatic sections were available, intraindividual variation in copper distribution across hepatic sections was evaluated. RESULTS: Median hepatic copper concentrations obtained with digital image analysis exceeded concentrations obtained with AAS or ICP-MS. Concentrations were also higher in older dogs (≥ 9 years vs < 9 years), dogs of breeds with a typical body weight ≥ 20 kg (44 lb), and dogs with necroinflammatory changes or uneven copper distribution. Qualitative copper accumulation scores were significantly associated with hepatic copper concentrations; however, the correlation between qualitative score and concentration obtained with digital image analysis (rs = 0.94) was higher than the correlation between qualitative score and concentration obtained with AAS (rs = 0.75) or ICP-MS (rs = 0.57). The coefficient of variation for hepatic copper concentrations obtained with digital image analysis was significantly higher for dogs with higher hepatic copper concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that spectroscopic-spectrometric analysis of hepatic biopsy specimens commonly underestimated the concentration obtained by digital image analysis of rhodanine-stained sections.

Relationships between congenital peritoneopericardial diaphragmatic hernia or congenital central diaphragmatic hernia and ductal plate malformations in dogs and cats.

OBJECTIVE: To characterize the association between peritoneopericardial diaphragmatic hernia (PPDH) or congenital central diaphragmatic hernia (CCDH) and ductal plate malformations (DPMs) in dogs and cats. ANIMALS: 18 dogs and 18 cats with PPDH or CCDH and 19 dogs and 18 cats without PPDH or CCDH. PROCEDURES: Evaluation of clinical details verified PPDH or CCDH and survival times. Histologic features of nonherniated liver samples were used to categorize DPM. Immunohistochemical staining for cytokeratin-19 distinguished bile duct profiles per portal tract and for Ki-67-assessed cholangiocyte proliferation. Histologic features of herniated liver samples from PPDH or CCDH were compared with those of pathological controls (traumatic diaphragmatic hernia, n = 6; liver lobe torsion, 6; ischemic hepatopathy, 2). RESULTS: DPM occurred in 13 of 18 dogs with the proliferative-like phenotype predominating and in 15 of 18 cats with evenly distributed proliferative-like and Caroli phenotypes. Congenital hepatic fibrosis DPM was noted in 3 dogs and 2 cats and renal DPM in 3 dogs and 3 cats. No signalment, clinical signs, or clinicopathologic features discriminated DPM. Kaplan Meier survival curves were similar in dogs and cats. Bile duct profiles per portal tract in dogs (median, 5.0; range, 1.4 to 100.8) and cats (6.6; 1.9 to 11.0) with congenital diaphragmatic hernias significantly exceeded those in healthy dogs (1.4; 1.2 to 1.6) and cats (2.3; 1.7 to 2.6). Animals with DPM lacked active cholangiocyte proliferation. Histologic features characterizing malformative bile duct profiles yet without biliary proliferation were preserved in herniated liver lobes in animals with DPM. CONCLUSIONS AND CLINICAL RELEVANCE: DPM was strongly associated with PPDH and CCDH. Because DPM can impact health, awareness of its coexistence with PPDH or CCDH should prompt biopsy of nonherniated liver tissue during surgical correction of PPDH and CCDH.

Influence of treatment with ultralow-dose aspirin on platelet aggregation as measured by whole blood impedance aggregometry and platelet P-selectin expression in clinically normal dogs.

OBJECTIVE: To evaluate the influence of treatment with ultralow-dose aspirin (ULDAsp) on platelet aggregation, P-selectin (CD62P) expression, and formation of platelet-leukocyte aggregates in clinically normal dogs. ANIMALS: 18 clinically normal dogs. PROCEDURES: Studies were conducted before and 24 hours after ULDAsp administration (0.5 mg/kg, PO, q 24 h, for 2 days). Whole blood impedance aggregometry for the assessment of platelet function was performed with sodium citrate-anticoagulated blood and aggregation agonists (ADP at 20, 10, and 5 µmol/L; collagen at 10, 5, and 2 µg/mL). Onset, maximum response, and rate of platelet aggregation were recorded. Flow cytometric assays were configured to detect thrombin-induced CD62P expression and platelet-leukocyte aggregates in EDTA-anticoagulated whole blood. Externalized platelet CD62P and constitutive CD61 (GPIIIa) were labeled with antibodies conjugated to phycoerythrin (PE) and fluorescein isothiocyanate (FITC), respectively. Red blood cell-lysed paraformaldehyde-fixed EDTA-anticoagulated whole blood was dual labeled with CD61-FITC and a panleukocyte antibody (CD18-PE) to characterize platelet-leukocyte aggregates. RESULTS: ULDAsp significantly delayed platelet aggregation onset with ADP at 20 µmol/L by 54% to 104%, attenuated maximum aggregation with various concentrations of ADP and collagen by ≥ 41%, and slowed aggregation rate with the highest ADP and collagen concentrations by ≥ 39%. Depending on the parameter tested, up to 30% of dogs failed to have an ULDAsp effect. Thrombin stimulation significantly increased CD62P expression in platelets and platelet-leukocyte aggregates, but ULDAsp did not alter basal or thrombin-stimulated CD62P expression. CONCLUSIONS AND CLINICAL RELEVANCE: ULDAsp treatment of clinically normal dogs impaired platelet aggregation in most dogs, but did not influence CD62P platelet membrane expression.

Congenital erythropoietic protoporphyria and protoporphyric hepatopathy in a dog.

CASE DESCRIPTION: A 6-month-old sexually intact male Clumber Spaniel was evaluated because of small stature, recurrent dermatitis of the head, and progressive pigmentary hepatopathy. CLINICAL FINDINGS: Clinicopathologic findings included nonanemic hypochromic microcytosis, hypocholesterolemia, persistently high serum liver enzyme activities, and anicteric hyperbilirubinemia. Histologic examination of liver biopsy specimens collected when the dog was 6 months and 2 years of age revealed expansion and bridging of portal tracts, occasional centrilobular parenchymal collapse, scattered lymphoplasmacytic infiltrates, and dark red to brown pigment within large aggregates of macrophages, engorged bile canaliculi, and hepatocytes. The pigment failed to stain for the presence of iron, copper, bile, and glycoprotein and, when examined with polarized microscopy, emitted a yellow to green birefringence with occasional Maltese cross configurations. Further analyses confirmed marked porphyrin accumulation in blood, urine, feces, and liver tissue; protoporphyrin accumulation in RBCs and liver tissue; and a signature porphyrin profile and fluorescence peak consistent with erythropoietic protoporphyria. Advanced protoporphyric hepatopathy was diagnosed. The chronic dermatopathy was presumed to reflect protoporphyric photosensitivity. TREATMENT AND OUTCOME: Management was focused on avoiding conditions known to induce heme synthesis and catabolism, administrating ursodeoxycholic acid and antioxidants S-adenosylmethionine and vitamin E, and avoiding sunlight exposure. At follow-up at 4 years of age, the dog was stable without evidence of jaundice but with probable persistent erythropoietic protoporphyria-related solar dermatopathy. CLINICAL RELEVANCE: Clinical and histologic features of congenital erythropoietic protoporphyria and resultant protoporphyric hepatopathy, the diagnosis, and the successful management of a dog with these conditions over 4 years were described. Veterinarians should consider porphyric syndromes when unusual pigmentary hepatopathies are encountered.

Clinical, clinicopathologic, and hepatic histopathologic features associated with probable ketoconazole-induced liver injury in dogs: 15 cases (2015-2018).

OBJECTIVE: To characterize clinical, clinicopathologic, and hepatic histopathologic features and outcome for dogs with probable ketoconazole-induced liver injury. ANIMALS: 15 dogs with suspected ketoconazole-induced liver injury that underwent liver biopsy. PROCEDURES: Medical record data were summarized regarding signalment, clinical signs, clinicopathologic and hepatic histopathologic findings, concurrent medications, ketoconazole dose, treatment duration, and outcome. RESULTS: Median age and body weight were 8.2 years (range, 5 to 15 years) and 13.0 kg (28.6 lb; range, 8.2 to 38.0 kg [18.0 to 83.6 lb]), respectively. The most common breed was Cocker Spaniel (n = 5). All dogs received ketoconazole to treat cutaneous Malassezia infections. Median daily ketoconazole dose was 7.8 mg/kg (3.5 mg/lb; range, 4.4 to 26.0 mg/kg [2.0 to 11.8 mg/lb]), PO. Treatment duration ranged from 0.3 to 100 cumulative weeks (intermittent cyclic administration in some dogs); 6 dogs were treated for ≤ 10 days. Common clinical signs included lethargy, anorexia, and vomiting. All dogs developed high serum liver enzyme activities. Hepatic histopathologic findings included variable lobular injury, mixed inflammatory infiltrates, and conspicuous aggregates of ceroid-lipofuscin-engorged macrophages that marked regions of parenchymal damage. Five dogs developed chronic hepatitis, including 3 with pyogranulomatous inflammation. Of the 10 dogs reported to have died at last follow-up, survival time after illness onset ranged from 0.5 to 165 weeks, with 7 dogs dying of liver-related causes. CONCLUSIONS AND CLINICAL RELEVANCE: Findings for dogs with hepatotoxicosis circumstantially associated with ketoconazole treatment suggested proactive monitoring of serum liver enzyme activities is advisable before and sequentially after initiation of such treatment.

Influence of biopsy specimen size, tissue fixation, and assay variation on copper, iron, and zinc concentrations in canine livers.

OBJECTIVE-To determine whether metal concentrations in canine liver specimens were influenced by specimen size, assay variability, tissue processing (formalin fixation and deparaffinization), or storage in paraffin blocks. SAMPLE POPULATION-Liver specimens (fresh frozen and deparaffinized) from 2 dogs with chronic hepatitis (high copper but unremarkable iron concentration [liver 1] and unremarkable copper but high iron concentration [liver 2]) as well as fresh and deparaffinized-archived liver specimens from 20 dogs with various hepatopathies. PROCEDURES-Fresh frozen liver specimens (obtained via simulated needle-core and wedge biopsy), fresh hepatic tissue, and deparaffinized-archived specimens (0.5 to 14 years old) were analyzed for concentrations of copper, iron, and zinc by atomic absorption flame spectrometry. Clinical severity scores were assigned on the basis of tissue metal concentrations. RESULTS-Interassay variation of metal standards was < 4%. Measurements of liver tissues on 8 consecutive days yielded high coefficients of variation (3.6% to 50%) reflecting heterogenous histologic metal distribution; variation was highest in liver 1 and deparaffinized-archived tissues. Heterogenous metal distribution was confirmed by histologic evaluation. The largest range of metal concentrations was detected in wedge biopsy specimens. In tissues with high metal concentrations, copper and iron concentrations were significantly lower in needle-core versus wedge biopsy specimens. A higher zinc concentration in deparaffinized-archived specimens masked a low zinc concentration in fresh liver tissue of 10 of 20 (50%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE-Retrospective measurement of copper and iron concentrations but not zinc concentrations in deparaffinized-archived liver specimens provided relevant information. The value of needle-core biopsy specimens for measurement of metal concentrations is questionable.

Reference limits for hepatic bile duct-to-arteriole and bile duct-to-portal tract ratios in healthy cats.

OBJECTIVE To establish reference limits for hepatic bile duct-to-arteriole ratio (BD:A) and bile duct-to-portal tract ratio (BD:PT) in healthy cats and assess whether these parameters could be used to support a diagnosis of biliary ductopenia in cats. SAMPLE Hepatic biopsy samples from healthy cats (n = 20) and cats with ductopenia (2). PROCEDURES Hepatic biopsy samples from healthy cats were used to count the number of bile ducts and hepatic arterioles in 20 portal tracts for each cat. Mean BD:A and mean BD:PT for each cat were calculated, and these values were used to determine reference limits for mean BD:A and mean BD:PT. Results of histologic evaluation, including immunohistochemical staining in some instances, were compared for healthy cats versus cats with ductopenia. RESULTS Of the 400 portal tracts from healthy cats, 382 (95.5%) and 396 (99.0%) had BD:A and BD:PT, respectively, ≥ 1.0, with less variability in BD:A. Mean BD:A and BD:PT were markedly lower in both cats with ductopenia, compared with values for healthy cats. However, only mean BD:A for cats with ductopenia was below the reference limit of 0.59. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that systematic evaluation of BD:A, with a lower reference limit of 0.59 to define biliary ductopenia in cats, may be a discrete and easily applied morphometric tool to enhance detection of ductopenia in cats. However, application of this ratio required evaluation of ≥ 20 portal tracts with cross-sectioned portal elements to determine a mean BD:A value.

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs.

This consensus statement on chronic hepatitis (CH) in dogs is based on the expert opinion of 7 specialists with extensive experience in diagnosing, treating, and conducting clinical research in hepatology in dogs. It was generated from expert opinion and information gathered from searching of PubMed for manuscripts on CH, the Veterinary Information Network for abstracts and conference proceeding from annual meetings of the American College of Veterinary Medicine and the European College of Veterinary Medicine, and selected manuscripts from the human literature on CH. The panel recognizes that the diagnosis and treatment of CH in the dog is a complex process that requires integration of clinical presentation with clinical pathology, diagnostic imaging, and hepatic biopsy. Essential to this process is an index of suspicion for CH, knowledge of how to best collect tissue samples, access to a pathologist with experience in assessing hepatic histopathology, knowledge of reasonable medical interventions, and a strategy for monitoring treatment response and complications.

Changes in gallbladder volume in healthy dogs after food was withheld for 12 hours followed by ingestion of a meal or a meal containing erythromycin.

OBJECTIVE: To assess the influence of meal ingestion and orally administered erythromycin on gallbladder volume in dogs. ANIMALS: 22 healthy dogs. PROCEDURES: Ultrasonographically determined gallbladder dimensions in unsedated dogs were used to calculate volume. Measurements were recorded after food was withheld for 12 hours (time 0) and 15, 30, 45, 60, 90, and 120 minutes after a 100-g meal without (n = 22) or with erythromycin (1.0 mg/kg [7], 2.5 mg/kg [7], and both dosages [8]). Gallbladder ejection fraction represented the percentage of volume change from time 0. Intraday and interday coefficients of variation determined operator repeatability and physiologic variation. RESULTS: We did not detect significant differences in gallbladder volume per unit of body weight between treatments at time 0 or in ejection fraction percentage within or between treatments. Median time 0 gallbladder volume was 0.6 mL/kg (range, 0.4 to 1.9) but was > 1.0 mL/kg in 3 of 22 (14%) dogs and or= 25% with at least 1 treatment, but 2 dogs with a gallbladder volume or= 25% were typical. No treatment consistently induced greater gallbladder contraction. Dogs with a gallbladder volume > 1.0 mL/kg and ejection fraction < 25% may require a combined meal and erythromycin protocol.

Clinical and clinicopathologic features of dogs that consumed foodborne hepatotoxic aflatoxins: 72 cases (2005-2006).

OBJECTIVE: To characterize clinical signs, clinicopathologic features, treatments, and survival in dogs with naturally acquired foodborne aflatoxicosis. DESIGN: Retrospective case series. ANIMALS: 72 dogs that consumed aflatoxin-contaminated commercial dog food. PROCEDURES: Medical records of affected dogs were reviewed. Between December 2005 and March 2006, dogs were identified as having foodborne aflatoxin hepatotoxicosis on the basis of the history of consumption of contaminated food or characteristic histopathologic lesions (subject dog or a recently deceased dog in the same household or kennel). Recorded information included signalment, clinical features, clinicopathologic test results, treatments, and survival. Data were analyzed by survival status. RESULTS: Most dogs were of large breeds from breeding kennels. No significant differences were found in age or weight between 26 (36%) survivor dogs and 46 (64%) nonsurvivor dogs. Severity of clinical signs varied widely; 7 dogs died abruptly. In order of onset, clinical features included anorexia, lethargy, vomiting, jaundice, diarrhea (melena, hematochezia), abdominal effusion, peripheral edema, and terminal encephalopathy and hemorrhagic diathesis. Common clinicopathologic features included coagulopathic and electrolyte disturbances, hypoproteinemia, increased serum liver enzyme activities, hyperbilirubinemia, and hypocholesterolemia. Cytologic hepatocellular lipid vacuolation was confirmed in 11 dogs examined. In comparisons of clinicopathologic test results between survivor and nonsurvivor dogs, only granular cylindruria (7/21 dogs) consistently predicted death. Best early markers of aflatoxicosis were low plasma activities of anticoagulant proteins (protein C, antithrombin) and hypocholesterolemia. Despite aggressive treatment, many but not all severely affected dogs died. CONCLUSIONS AND CLINICAL RELEVANCE: Serum liver enzyme activities and bilirubin concentration were unreliable early markers of aflatoxin hepatotoxicosis in dogs. Hypocholesterolemia and decreased plasma protein C and antithrombin activities may function as exposure biomarkers.

Gallbladder disease in Shetland Sheepdogs: 38 cases (1995-2005).

OBJECTIVE: To determine risk, clinical features, and treatment responses for gallbladder disorders in Shetland Sheepdogs. DESIGN: Retrospective case-control study. ANIMALS: 38 Shetland Sheepdogs with gallbladder disease. PROCEDURES: Medical records were reviewed for signalment, history, physical findings, laboratory results, imaging features, coexistent illnesses, histologic findings, treatments, and survival rates. RESULTS: Mature dogs with gastrointestinal signs were predisposed (odds ratio, 7.2) to gallbladder disorders. Gallbladder mucocele was confirmed in 25 dogs. Concurrent problems included pancreatitis, hyperlipidemia, corticosteroid excess, hypothyroidism, protein-losing nephropathy, diabetes mellitus, cholelithiasis, and gallbladder dysmotility. Mortality rate was 68% with and 32% without bile peritonitis. Nonsurvivors had high WBC and neutrophil count and low potassium concentration. Although preprandial hypercholesterolemia, hypertriglyceridemia, and high serum liver enzyme activities were common, gallbladder disease was serendipitously discovered in 11 of 38 dogs. Histologic examination (n=20 dogs) revealed gallbladder cystic mucosal hyperplasia in 20 dogs, cholecystitis in 16, periportal hepatitis in 9, and vacuolar hepatopathy in 7. Surgery included cholecystectomy (n=17) and cholecystoenterostomy (4). In 1 hyperlipidemic dog without clinical signs, gallbladder mucocele resolved 6 months after beginning use of a fat-restricted diet and ursodeoxycholic acid. CONCLUSIONS AND CLINICAL RELEVANCE: Shetland Sheepdogs are predisposed to gallbladder disorders, with mucoceles and concurrent dyslipidemia or dysmotility in many affected dogs. Most dogs were without clinical signs during mucocele development. Low survival rate after cholecystectomy in clinically affected dogs suggested that preemptive surgical interventions may be a more appropriate treatment strategy.

Interpretation of liver enzymes.

Abnormalities in liver enzymes are commonly encountered in clinical practice. Knowledgeable assessment requires a full understanding of their pathophysiology and provides an important means of detecting the earliest stage of many serious hepatobiliary disorders. The best interpretations are achieved using an integrated approach, combining historical and physical findings with routine and specialized diagnostic procedures and imaging studies. Information in this article provides the foundation, by example, for understanding the reliability of single time point enzyme measurements, the value of sequential measurements, the importance of interpreting the activity of enzymes in light of their half life and tissue of origin, and the influence of the induction phenomenon.