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.
Objective—To determine total glutathione (GSH) and
glutathione disulfide (GSSG) concentrations in liver
tissues from dogs and cats with spontaneous liver
Sample Population—Liver biopsy specimens from
63 dogs and 20 cats with liver disease and 12 healthy
dogs and 15 healthy cats.
Procedure—GSH was measured by use of an enzymatic
method; GSSG was measured after 2-vinylpyridine
extraction of reduced GSH. Concentrations were
expressed by use of wet liver weight and concentration
of tissue protein and DNA.
Results—Disorders included necroinflammatory liver
diseases (24 dogs, 10 cats), extrahepatic bile duct
obstruction (8 dogs, 3 cats), vacuolar hepatopathy (16
dogs), hepatic lipidosis (4 cats), portosystemic vascular
anomalies (15 dogs), and hepatic lymphosarcoma
(3 cats). Significantly higher liver GSH and protein
concentrations and a lower tissue DNA concentration
and ratio of reduced GSH-to-GSSG were found in
healthy cats, compared with healthy dogs. Of 63 dogs
and 20 cats with liver disease, 22 and 14 had low liver
concentrations of GSH (µmol) per gram of tissue; 10
and 10 had low liver concentrations of GSH (nmol) per
milligram of tissue protein; and 26 and 18 had low
liver concentrations of GSH (nmol) per microgram of
tissue DNA, respectively. Low liver tissue concentrations
of GSH were found in cats with necroinflammatory
liver disease and hepatic lipidosis. Low liver concentrations
of GSH per microgram of tissue DNA
were found in dogs with necroinflammatory liver disease
and cats with necroinflammatory liver disease,
extrahepatic bile duct occlusion, and hepatic lipidosis.
Conclusions and Clinical Relevance—Low GSH values
are common in necroinflammatory liver disorders,
extrahepatic bile duct occlusion, and feline
hepatic lipidosis. Cats may have higher risk than dogs
for low liver GSH concentrations. (Am J Vet Res
Objective—To evaluate the accuracy of digitally scanned rhodanine-stained liver biopsy specimens for determination of hepatic copper concentration and compare results with qualitatively assigned histologic copper scores in dogs.
Sample—353 liver biopsy specimens from dogs.
Procedures—Specimens (n = 139) with quantified copper concentration ranging from 93 to 6,900 μg/g were allocated to group 1 (< 400 μg/g ), group 2 (401 to 1,000 μg/g ), group 3 (1,001 to 2,000 μg/g ), and group 4 (> 2,001 μg/g ); stained with rhodanine; and digitally scanned and analyzed with a proprietary positive pixel algorithm. Measured versus calculated copper concentrations were compared, and limits of agreement determined. Influence of nodular remodeling, fibrosis, or parenchymal loss on copper concentration was determined by digitally analyzing selected regions in 17 specimens. After method validation, 214 additional liver specimens underwent digital scanning for copper concentration determination. All sections (n = 353) were then independently scored by 2 naive evaluators with a qualitative scoring schema. Agreement between assigned scores and between assigned scores and tissue copper concentrations was determined.
Results—Linear regression was used to develop a formula for calculating hepatic copper concentration ≥ 400 μg/g from scanned sections. Copper concentrations in unremodeled specimens were significantly higher than in remodeled specimens. Qualitative scores widely overlapped among quantitative copper concentration groups.
Conclusions and Clinical Relevance—Calculated copper concentrations determined by means of digital scanning of rhodanine-stained liver sections were highly correlated with measured values and more accurate than qualitative copper scores, which should improve diagnostic usefulness of hepatic copper concentrations and assessments in sequential biopsy specimens.
Objective—To investigate the influence of dietary supplementation with l-carnitine on metabolic rate, fatty acid oxidation, weight loss, and lean body mass (LBM) in overweight cats undergoing rapid weight reduction.
Procedures—Cats fattened through unrestricted ingestion of an energy-dense diet for 6 months were randomly assigned to 4 groups and fed a weight reduction diet supplemented with 0 (control), 50, 100, or 150 μg of carnitine/g of diet (unrestricted for 1 month, then restricted). Measurements included resting energy expenditure, respiratory quotient, daily energy expenditure, LBM, and fatty acid oxidation. Following weight loss, cats were allowed unrestricted feeding of the energy-dense diet to investigate weight gain after test diet cessation.
Results—Median weekly weight loss in all groups was ≥ 1.3%, with no difference among groups in overall or cumulative percentage weight loss. During restricted feeding, the resting energy expenditure-to-LBM ratio was significantly higher in cats that received l-carnitine than in those that received the control diet. Respiratory quotient was significantly lower in each cat that received l-carnitine on day 42, compared with the value before the diet began, and in all cats that received l-carnitine, compared with the control group throughout restricted feeding. A significant increase in palmitate flux rate in cats fed the diet with 150 μg of carnitine/g relative to the flux rate in the control group on day 42 corresponded to significantly increased stoichiometric fat oxidation in the l-carnitine diet group (> 62% vs 14% for the control group). Weight gain (as high as 28%) was evident within 35 days after unrestricted feeding was reintroduced.
Conclusions and Clinical Relevance—Dietary l-carnitine supplementation appeared to have a metabolic effect in overweight cats undergoing rapid weight loss that facilitated fatty acid oxidation.
To characterize clinical features, comorbidities, frequency of bacterial isolation, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS).
168 client-owned cats with S-CCHS.
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.
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.
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.
Objective—To evaluate concentrations of calcium, phosphorus, zinc, iron, copper, manganese, and selenium in several commercially available dry dog foods and compare these with current Association of American Feed Control Officials (AAFCO) recommendations for maintenance of healthy dogs.
Sample—45 over-the-counter dry foods formulated for maintenance of healthy dogs (ie, maintenance foods) and 5 therapeutic dry foods formulated for dogs with hepatic or renal disease.
Procedures—Mineral concentrations were measured via inductively coupled plasma mass spectrometry or inductively coupled plasma atomic emission spectroscopy and compared with AAFCO-recommended minimum and maximum values.
Results—Most (39/45) maintenance foods were in compliance with AAFCO recommendations for all mineral concentrations evaluated. Calcium concentration was > 7. 1 g/1,000 kcal of metabolizable energy (ME) in 4 of 45 maintenance foods, and phosphorus concentration was > 4.6 g/1,000 kcal ME in 3 of these; 2 maintenance foods contained < 34 mg of zinc/1,000 kcal ME. These values were not within AAFCO-recommended ranges. Calcium-to-phosphorus ratio in foods formulated for dogs with renal disease was above, and copper concentration in foods formulated for dogs with hepatic disease was below, recommended ranges for healthy dogs.
Conclusions and Clinical Relevance—Calcium concentrations exceeded recommended limits in some maintenance foods labeled for all life stages, underscoring the need to feed diets appropriately formulated for specific life stages, particularly for large- and giant-breed puppies. Studies investigating the bioavailability of minerals are necessary before firm recommendations can be made.
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.
To determine whether body weight, age, or sex was associated with ultrasonographically determined adrenal gland thickness (AT) in dogs with non-adrenal gland illness.
Retrospective cross-sectional study.
266 dogs (22 sexually intact and 119 castrated males and 19 sexually intact and 106 spayed females representing 12 breeds) with non-adrenal gland illness.
Thickness of the caudal pole of the left and right adrenal glands was measured on longitudinal ultrasonographic images. Dogs were stratified into age and body weight categories to investigate associations with AT.
AT was significantly lower in dogs that weighed ≤ 12 kg (26.4 lb) than in dogs that weighed > 12 kg and left AT increased with age. Both left and right AT were larger in male than in female dogs that weighed > 12 to ≤ 20 kg, and left AT was larger in male than in female dogs that weighed > 20 to ≤ 30 kg.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that body weight, age, and sex were significantly associated with AT, indicating that these variables should be considered when evaluating AT in dogs with non-adrenal gland illness and when developing reference intervals for AT in dogs. Further, findings indicated that dogs with non-adrenal gland illness that weigh ≤ 12 kg should have an AT no greater than 0.62 cm, whereas dogs that weigh > 12 kg should have an AT no greater than 0.72 cm.
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 , 2.5 mg/kg , and both dosages ). 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 ≤ 1.0 mL/kg in 19 of 22 (86%) dogs. Twenty dogs achieved an ejection fraction ≥ 25% with at least 1 treatment, but 2 dogs with a gallbladder volume ≤ 1.0 mL/kg at time 0 did not. Intraday and interday coefficients of variation were 18% and 25%, respectively.
Conclusions and Clinical Relevance—Gallbladder volume ≤ 1.0 mL/kg at time 0 and ejection fraction ≥ 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.
A 6-month-old sexually intact male Clumber Spaniel was evaluated because of small stature, recurrent dermatitis of the head, and progressive pigmentary hepatopathy.
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 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.