Dog Liver Research Articles

Evaluation of liver and spleen stiffness of healthy dogs by use of two-dimensional shear wave elastography

To assess liver and spleen stiffness in healthy dogs by use of a novel 2-D shear wave elastography (SWE) technique and to investigate the repeatability and reproducibility of the technique. 8 healthy adult Beagles. 2-D SWE was performed on each dog to assess liver and spleen stiffness. Repeatability (intraday variability) and reproducibility (interday variability) of 2-D SWE were investigated. For all 8 dogs, 2-D SWE was performed 3 times in 1 day (4-hour intervals) and on 3 separate days (1-week interval). Data were expressed as mean ± SD values for shear wave velocity and the Young modulus in the liver and spleen. Intraday and interday coefficients of variation were assessed for all variables. Mean ± SD shear wave velocity obtained for the liver and spleen was 1.51 ± 0.08 m/s and 2.18 ± 0.27 m/s, respectively. Mean value for the Young modulus obtained for the liver and spleen was 6.93 ± 0.79 kPa and 14.66 ± 3.79 kPa, respectively. Elasticity values were significantly higher for the spleen than for the liver. Intraday and interday coefficients of variation for all variables were < 25% (range, 3.90% to 20.70%). 2-D SWE was a feasible technique for assessing liver and spleen stiffness of healthy dogs. Future studies on the application of 2-D SWE for dogs with chronic hepatitis, cirrhosis, and portal hypertension are needed to evaluate the clinical applicability of 2-D SWE.

Identification of novel glutathione conjugates of terbinafine in liver microsomes and hepatocytes across species

1. Terbinafine (TBF), a common antifungal agent, has been associated with rare incidences of hepatotoxicity. It is hypothesized that bioactivation of TBF to reactive intermediates and subsequent binding to critical cellular proteins may contribute to this toxicity. In the present study, we have characterized the bioactivation pathways of TBF extensively in human, mouse, monkey, dog and rat liver microsomes and hepatocytes.2. A total of twenty glutathione conjugates of TBF were identified in hepatocytes; thirteen of these conjugates were also detected in liver microsomes. To the best of our knowledge, only two of these conjugates have been reported previously. The conjugates were categorized into three groups based on their mechanism of formation: (a) alkene/alkyne oxidation followed by glutathione conjugation, with or without N-demethylation, (b) arene oxidation followed by glutathione conjugation, with or without N-demethylation, and (c) N-dealkylation followed by glutathione conjugation of the allylic aldehyde, alcohol and acid intermediates.3. Differences were observed across species in the contributions of these pathways toward overall metabolic turnover. We conclude that, in addition to the glutathione conjugates known to form by Michael addition to the allylic aldehyde, there are other pathways involving the formation of arene oxides and alkene/alkyne epoxides that may be relevant to the discussion of TBF-mediated idiosyncratic drug reactions.

A patch-based super resolution algorithm for improving image resolution in clinical mass spectrometry

Mass spectrometry imaging (MSI) and histology are complementary analytical tools. Integration of the two imaging modalities can enhance the spatial resolution of the MSI beyond its experimental limits. Patch-based super resolution (PBSR) is a method where high spatial resolution features from one image modality guide the reconstruction of a low resolution image from a second modality. The principle of PBSR lies in image redundancy and aims at finding similar pixels in the neighborhood of a central pixel that are then used to guide reconstruction of the central pixel. In this work, we employed PBSR to increase the resolution of MSI. We validated the proposed pipeline by using a phantom image (micro-dissected logo within a tissue) and mouse cerebellum samples. We compared the performance of the PBSR with other well-known methods: linear interpolation (LI) and image fusion (IF). Quantitative and qualitative assessment showed advantage over the former and comparability with the latter. Furthermore, we demonstrated the potential applicability of PBSR in a clinical setting by accurately integrating structural (i.e., histological) and molecular (i.e., MSI) information from a case study of a dog liver.

Characterization of Fasiglifam-Related Liver Toxicity in Dogs.

Fasiglifam, a potent and highly selective agonist of G protein-coupled receptor 40, was developed for the treatment of type 2 diabetes mellitus. However, phase III clinical programs were terminated owing to liver safety concerns. Fasiglifam-related liver toxicity was also observed in repeat-dose dog toxicology studies, characterized by granulomatous inflammation with crystal formation in the liver and/or bile ducts. These histopathological changes were not observed in rat toxicology studies. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of dog liver sections obtained from a repeat-dose toxicology study indicated that the crystalline material in the affected dog liver contained fasiglifam and fasiglifam glucuronide (fasiglifam-G). Nonclinical mechanistic studies indicated that after 14 days of repeated oral dosing with [14C]fasiglifam at 200 mg/kg per day to dogs, the concentrations of fasiglifam and fasiglifam-G in the bile exceeded the solubility limit of these compounds in the bile (approximately 3000 µg/ml). After single oral 2- and 200-mg/kg doses administered to rats and dogs, fasiglifam and fasiglifam-G concentrations in dog bile were 5- to 10-fold higher than those in rat bile for the same dose of fasiglifam, while the bile flow rate adjusted by body weight was 4- to 8-fold lower in dogs than in rats. High fasiglifam and fasiglifam-G concentrations in dog bile together with lower bile flow rate could cause crystal formation in dog bile, resulting in secondary granulomatous inflammation in the dog liver.

Biomarkers of oxidative stress as an assessment of the redox status of the liver in dogs.

BackgroundOxidative stress is associated with a diverse group of liver disorders across species.ObjectivesDetermine whether glutathione (GSH) concentration in plasma and red blood cells correlates with liver GSH concentration in dogs and evaluate whether other markers of systemic oxidative stress, plasma vitamin E and urine 8‐isoprostanes/creatinine (F2‐IsoPs/Cr) concentrations, correlate with liver GSH.AnimalsThirty‐four client‐owned dogs undergoing clinically indicated liver biopsy and 15 healthy control dogs.MethodsProspective, observational cross‐sectional study. Urine and blood were collected before liver biopsy. Plasma, erythrocyte, and liver GSH were measured using high performance liquid chromatography (HPLC); vitamin E was measured by HPLC, and F2‐IsoPs/Cr was measured by gas chromatography/mass spectrometry.ResultsAll dogs were treated at the discretion of the attending clinician (24/34 received antioxidants; 4/34 fed therapeutic liver diet), which included dogs with primary or secondary liver disease (inflammatory (n = 21), metabolic (n = 9), vascular (n = 2), and neoplastic (n = 2)). Median GSH concentrations in plasma, erythrocyte, and liver were 0.18 mg/dL (range 0.14 to 0.56 mg/dL), 56.7 mg/dL (18.3 to 79.2 mg/dL), and 181 mg/dL (39.9 to 527 mg/dL), respectively. No significant correlations were found between liver GSH and erythrocyte GSH, plasma GSH, vitamin E, or F2‐IsoPs/Cr. Dogs undergoing clinically indicated liver biopsy had significantly higher urine F2‐IsoPs/Cr than did healthy controls (5.89 vs 2.98 ng/mg; P < .0001).Conclusions and Clinical ImportanceErythrocyte and plasma GSH are not indicative of liver GSH concentration in dogs. In addition, dogs undergoing clinically indicated liver biopsy have evidence of increased systemic oxidative stress compared to healthy controls.

Metabolism of Scoparone in Experimental Animals and Humans.

Scoparone, a major constituent of the Chinese herbal medicine Yin Chen Hao, expresses beneficial effects in experimental models of various diseases. The intrinsic doses and effects of scoparone are dependent on its metabolism, both in humans and animals. We evaluated in detail the metabolism of scoparone in human, mouse, rat, pig, dog, and rabbit liver microsomes in vitro and in humans in vivo. Oxidation of scoparone to isoscopoletin via 6-O-demethylation was the major metabolic pathway in liver microsomes from humans, mouse, rat, pig and dog, whereas 7-O-demethylation to scopoletin was the main reaction in rabbit. The scoparone oxidation rates in liver microsomes were 0.8 - 1.2 µmol/(min*g protein) in mouse, pig, and rabbit, 0.2 - 0.4 µmol/(min*g protein) in man and dog, and less than 0.1 µmol/(min*g) in rat. In liver microsomes of all species, isoscopoletin was oxidized to 3-[4-methoxy-ρ-(3, 6)-benzoquinone]-2-propenoate and esculetin, which was formed also in the oxidation of scopoletin. Human CYP2A13 exhibited the highest rate of isoscopoletin and scopoletin oxidation, followed by CYP1A1 and CYP1A2. Glucuronidation of isoscopoletin and scopoletin was catalyzed by the human UGT1A1, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, and UGT2B17. Dog was most similar to man in scoparone metabolism. Isoscopoletin glucuronide and sulfate conjugates were the major scoparone in vivo metabolites in humans, and they were completely excreted within 24 h in urine. Scoparone and its metabolites did not activate key nuclear receptors regulating CYP and UGT enzymes. These results outline comprehensively the metabolic pathways of scoparone in man and key preclinical animal species.

Fatty Acid Compositions of Ceramides and Sphingomyelins in Mammalian Tissues and Cultured Cells

Sphingolipids consist of a sphingoid base N-linked to a fatty acyl chain. Among them, sphingomyelins (SM) are major components of mammalian cells, while ceramide (Cer) plays an important role as a lipid second messenger. We have performed a quantitative lipidomic study of Cer and SM species in different mammalian tissues (adipose tissue, liver, brain and blood serum of human, mice, rat and dog), as well as in cell cultures of mammalian origin (primary hepatocytes, immortalized MDCK cells, mice melanoma b16 cells, and mice primary CD4+ T lymphocytes) using an ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-ToF-MS)-based platform. The data have been compared with published, in general semi-quantitative, results from 20 other samples, with good agreement. The sphingoid base was predominantly d18-1 sphingosine (2-amino-4-octadecene-1,3-diol) in all cases. The fatty acid composition of SM was clearly different from that of Cer. In virtually all samples the most abundant Cer species were those containing C24:0 and C24:1 in their N-acyl chains, while the main species contained in SM was C16:0. Brain was the most divergent tissue, in which Cer and SM C18:0 were very abundant.

Atipamezole is a promising non-discriminative inhibitor against pan-CYP450 including diclofenac 4′-hydroxylation: A comparison with ABT for drug ADME optimization and mechanism study

1-aminobenzotriazole (ABT) is a known P450 enzyme non-selective inactivator that serves as a tool for assessing P450-mediated metabolism. However, many findings demonstrated that ABT was ineffective with human CYP2C9. A profound pan-CYP450 inhibitor is desired avoid the risk of incomplete inhibition of P450, especially CYP2C9. Atipamezole is commonly used to recover animals from sedation-anesthesia induced by α2−adrenoceptor agonists. The purpose of this study is to evaluate atipamezole as a non-selective inhibitor of P450 enzymes and compare it with ABT. Inhibition toward seven major human CYP450 isoform was determined for atipamezole and ABT in human, rat, and dog liver microsomes for the direct and time-dependent inhibition potentials. IC50 values toward human and animal CYPs without preincubation are 0.02–7.93 μM and 20.9–1798 μM for atipamezole and ABT, respectively. The IC50 values of ABT after preincubation shift to 4.06–460 μM. Atipamezole has more effective inhibition to CYP2C9 mediated diclofenac hydroxylation in human and animal liver microsomes with IC50 values of 1.50–5.20 μM than that of ABT at 74.7-460 μM. No IC50 shift was observed for atipamezole to CYP isoforms. In vivo utility of atipamezole was assessed by co-dosing with diclofenac in rats. At 30 mg/kg via oral, atipamezole enhanced the AUC of diclofenac by 13.1-fold and the Cmax by 5.6-fold. Similar enhancement also achieved for ABT (100 mg/kg) with AUC and Cmax increased 9.5 and 4.8-fold. As a reversible pan-CYP inhibitor, atipamezole showed less species difference than ABT. It provides a better and easier to use alternative to ABT for ADME optimization and elucidating mechanistic drug metabolism or toxicity studies.

Біорезонансний метод оцінки метаболічної функції печінки у собак

The study was conducted on 35 dogs of various breeds. In the blood of experimental animals, the number of formed elements was considered, the hemoglobin, total protein, protein fractions, urea, uric acid, ammonia, amino nitrogen, creatinine, glucose, glycogen, pyruvic acid and lactic acid concentrations, cholesterol, triacylglycerols were determined. Two groups of dogs were formed: the control group &ndash; without changes in the metabolic function of the liver and the experimental &ndash; with a decrease in this function. Then we used the program of individual bioresonance testing Parkes-D device for a comprehensive assessment of the state of organs and systems of animals, the electrical conductivity of biologically active points was determined with diagnostic markers and the efficiency and informativeness of the bioresonance method were compared. The decrease in the functional state of the metabolic function of the liver in dogs is characterized by a lower number of red blood cells 12.0-16.9% (p&lt;0.01) and a hemoglobin content in the blood 14.8-16.5% (p&lt;0.05), a significantly higher number of leukocytes 48.6-51.9% (p&lt;0.001) and a high content of total bilirubin in the blood 56.0-66.9% (p&lt;0.001). A decrease in the metabolism of proteins, fats and carbohydrates in the body of dogs were detected, in particular, a lower content of total protein was found 10.5% (p&lt;0.05) and albumin 13.1% (p&lt;0.05), higher content of amino nitrogen 11.7%, urea 69.4% (p&lt;0.001) and ammonia 22.0% (p&lt;0.01), a decrease in blood urea content 18.2% (p&lt;0.05), ammonia 9.8% (p&lt;0.05) and uric acid 11.9% (p&lt;0.05), a higher content of pyruvate 33.3% (p&lt;0.01) and lactate by 22.2% (p&lt;0.01), and the content of triacylglycerols, phospholipids and cholesterol was lower by 16.1% (p&lt;0.05), 21.4% (p&lt;0.05) and 13.0% (p&lt;0.05). During the study of the bioresonance with the help of markers of the functional state of the liver with diagnostic complex &ldquo;Parkes-D&rdquo; it was determined that out of 35 dogs 14 had a decrease in their metabolic function, and the data of 13 dogs correspond with laboratory blood values. It has been established that the use of functional testing by the hardware-software diagnostic complex &quot;Parkes-D&quot; allows to determine changes in the metabolic function of the liver with a probability up to 91.4%&nbsp

Detection of visceral leishmaniosis in feral dogs in Bangladesh by conventional and molecular methods

An investigation was carried out to recognize the occurrence of visceral leismaniosis(VL) in cattle, goats and dogs in the endemic zone of VL at Mymensingh district, Bangladesh. Venous blood, liver and spleen from the cattle, goats and dogs (50 from each) were collected from slaughter house during 2011 to 2015. Detection of the parasite was through examination of stained smear, histopathology and using polymerase chain reaction (PCR) technique. The investigations have revealed amastigote stage of Leishmania in the splenic smears of three dogs. Microgranulomas were seen in the liver of two dogs but amastigote stage of the parasite was not seen in the cytoplasm of macrophages. The PCR protocol was carried out using DNA from the blood, liver and spleen, targeting kinitoplast minicircle DNA (kDNA). A 145bp fragment of kDNA gene was amplified in positive cases of one cattle, seven goats and seven dogs. Two more PCR protocols were, adapted targeting 18S rRNA and cysteine proteases genes to support this observation. Genomic DNA from the blood, spleen and liver of cattle, goats and dogs while used in PCR amplified 18S rRNA and cysteine proteases gene specific fragments of Leishmania donovani in the spleen of two dogs. Phylogenetic analyses of 741bp fragment of the cysteine proteases gene confirmed that the protozoa as L. donovani. PCR protocol targeting 18S rRNA and cysteine proteases genes of Leishmania was found to be specific to detect L. donovani. This is the first report from Bangladesh confirming the visceral leishmaniosis in feral dogs using PCR. Thus, further investigations involving canids and other carrier animalsis required to curtail the incidence and or successful designing of VL eliminationcampaign in Bangladesh.

Phosphofructokinase-1 subunit composition and activity in the skeletal muscle, liver, and brain of dogs.

Phosphofructokinase-1 (EC:2.7.1.11, PFK-1) catalyzes the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate using adenosine triphosphate and is a key regulatory enzyme of glycolysis. Mammalian PFK-1 isozymes are composed of three kinds of subunits (PFK-M, -L, and -P), with different properties. It has been suggested that the proportion of PFK-1 subunits in different organs is based on the organ energy metabolism. In this study, we analyzed the activity and subunit composition of canine PFK-1. We found that, in dogs, the skeletal muscle only has PFK-M, the liver mainly has PFK-L, and the brain expresses all of them. The knowledge of the composition of PFK-1 could provide useful information for determination of the differences in glycolysis in various organs of dogs.

Histological and histochemical changes in the dogs liver at poisoning isoniazid

The article presents the results of macroscopic, histological and histochemical studies of dogs liver for isoniazid poisoning. The pathoanatomical section of 18 corpses of dogs of all ages and breeds has been carried out, fragments of different parts of the liver have been selected. Liver samples were fixed in a 10% aqueous solution of neutral formalin, Carnoua and Buena liquids. The dewatering in ethanol of increasing concentration was conducted, sealed in paraffin. The sections were made on a microtome MC-2 in the thickness of 7 microns, stained with hematoxylin and eosin, according to the technique of McManus, Pearles. The produced histoplasts were examined under a light microscope Leica DM 2500 (Switzerland), photocycled by the Leica DFC450C camera using the Leica Application Suite Version 4.4 software. Macroscopically, the liver in all studied corpses of dogs is enlarged, the edges are rounded, inhomogeneously colored (from dark cherry to light brown), loose consistency, a light bloody fluid is secreted on the cut, the structure of the organ is smoothed out. Optically light in the liver of most dogs for isoniazid poisoning noted profound violations of all structures of angioarhitectonics, stroma and parenchyma of the organ. Prevalent non-fibrotic changes in the endothelium, dilatation and deformation of central veins and sinusoidal mesh with the formation of cells filled with blood plasma. The expressed dystrophy and necrobiosis of hepatocytes and Kupferov cells were combined with erythrocyte hemolysis, which was reflected by the deposition of hemosiderin in the cytoplasm of macrophages and bilirubin in hepatocytes. In rare cases, in the liver of poisoned dogs, acute congestive hyperemia, diapedeous hemorrhages in peripartal regions and non-fibrotic changes in hepatocytes were observed. On the basis of conducted morphological studies, it can be argued that derivatives of isoniazid compounds in the dog's organism have a pronounced hepatotoxic effect characterized by a severe violation of blood and lymph microcirculation and all metabolic processes in liver cells, manifested by dystrophic-non-fibrotic processes in the body.

Proteomic analysis of liver tissue from dogs with chronic hepatitis.

Chronic hepatitis is the most common hepatic disease in dogs. Copper accumulation is an important cause of chronic hepatitis in dogs; however, the etiology in most dogs cannot be determined. Clinical signs of chronic hepatitis are often non-specific; therefore, this disease is frequently diagnosed in an advanced stage that makes successful intervention less likely. Early diagnosis of chronic hepatitis in dogs would thus be beneficial. The identification of proteins that are differentially expressed in dogs with chronic hepatitis could contribute to the development of novel diagnostic markers for this disease and provide insight into its pathogenesis. The objective of this study was to identify novel proteins that are differentially expressed in the liver of dogs with chronic hepatitis. Hepatic tissue was collected from 8 healthy dogs during ovariohysterectomy and from 8 dogs with histologically confirmed chronic hepatitis. The proteome of the liver samples was extracted by mechanical disruption and detergent-based cell lysis and differentially labeled prior to analysis by 2-dimensional fluorescence difference gel electrophoresis. Spots with an absolute fold change value > 2.0 were selected for further analysis. Protein identification was achieved by nanoflow liquid chromatography tandem mass spectrometry. Differential expression of select proteins was validated by Western blot. Five protein spots were differentially expressed between patients with chronic hepatitis and healthy control dogs. From these 5 protein spots 11 proteins were identified. Differential expression of cytokeratin 18 and annexin 5 were confirmed by Western blot analysis. Differential protein expression was shown between dogs with chronic hepatitis and healthy control dogs. Upregulation of cytokeratin 18 in chronic hepatitis may suggest increased hepatocellular apoptosis and necrosis, whereas upregulation of annexin 5A suggests increased hepatocellular apoptosis. Further studies are needed to determine whether either protein has diagnostic utility.

Paropisthorchis caninus Stephens, 1912: Synopsis of identity and pathological findings due to spontaneous infection in the liver of a street dog in Assam, India.

The present study describes a small liver fluke recovered at post-mortem and the pathological alteration produced by the parasite in the liver of a street dog from Assam, India. The spatulate parasite measured 3-4 mm in length and 1.0-1.25 mm in width with spiny body surface and showed a grossly visible peduncle projecting from the ventral surface at the anterior portion. The eggs of the parasite contained well developed miracidia. The parasite was identified as Paropisthorchis caninus. Identity of the parasite is discussed in the light of available literature and found to be morphologically different from other reported species of dog Opisthorchis. Pathological lesions observed in the liver included degeneration of hepatic parenchyma, hyperplasia of bile duct epithelium, fibrous tissue proliferation and formation of pseudo lobule which were the characteristics of chronic proliferative inflammation.

Metabolism of triacetone triperoxide (TATP) by canine cytochrome P450 2B11

This work is performed to determine if there is a potential for the accumulation and potential toxicity of triacetone triperoxide (TATP) in canines. Additional utility of this information may suggest human toxicity and possibly detection of biomarkers, metabolites or intact molecule of those using this material for nefarious reasons. Liquid chromatography/mass spectrometry of dog liver microsome (DLM) incubation samples of TATP was used to measure substrate depletion. Trapping of electrophilic products was performed using glutathione (GSH) and semicarbazide. Comparisons were made to free hydroperoxides found in methyl ethyl ketone peroxides (MEKP). The non-specific Km value of 2.2 μM and a Vmax of 1.1 nmol/min/mg of protein were determined. Canine recombinant cytochrome P450 (rCYP) 2B11 with human cytochrome b5 was found to catalyze the NADPH-dependent metabolism of TATP into its only phase I metabolite, hydroxy-TATP (TATP-OH). No secondary metabolite(s) or degraded products were detected or trapped from microsomal incubations. MEKP subjected to similar conditions was found to undergo significant metabolism, semicarbazide trapping and rapid oxidation of GSH to GSSG. The synthesized TATP-OH metabolite incubated in DLM progressed three times faster than TATP metabolism with no secondary metabolites found or trapped. TATP does not react as MEKP suggesting that TATP does not ring-open to form hydroperoxides. TATP and TATP-OH compete for the same enzyme, with TATP dominating this competition. Failure to detect additional metabolite(s) suggests they may be too small to detect by our system or bound covalently to a protein or polymer in the incubation reaction.

Hepatorenal arterial resistive and pulsatility indexes in dogs with ascites

Ascites is one of the complications in cirrhosis. Prognosis depends on systemic hemodynamics. This study was designed for determination of the liver and kidney hemodynamics in dogs with ascites via Doppler Ultrasonography (USG). 20 dogs with ascites and 10 healthy dogs were included. CBC, biochemical profile, USG and Doppler measurement were taken. Increased hepatic and renal RI and PI were statistically significant (p Less than 0,01-0,001). There were positive correlations between ALP and hepatic PI, between urea and renal RI, negative correlations between ALP and renal RI, between creatinine and hepatic and renal PI values (p less than 0,05-0,01). In conclusion, liver and kidney Doppler findings will help determination of the prognosis and implementation of effective treatment.

The fatty acids of sphingomyelins and ceramides in mammalian tissues and cultured cells: Biophysical and physiological implications.

Sphingolipids consist of a sphingoid base N-linked to a fatty acyl chain. Among them, sphingomyelins (SM) are major components of mammalian cells, while ceramide (Cer) plays an important role as a lipid second messenger. We have performed a quantitative lipidomic study of Cer and SM species in different mammalian tissues (adipose tissue, liver, brain and blood serum of human, mice, rat and dog), as well as in cell cultures of mammalian origin (primary hepatocytes, immortalized MDCK cells, mice melanoma b16 cells, and mice primary CD4 + T lymphocytes) using an ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-ToF-MS)-based platform. The data have been compared with published, in general semi-quantitative, results from 20 other samples, with good agreement. The sphingoid base was predominantly d18-1 sphingosine (2-amino-4-octadecene-1,3-diol) in all cases. The fatty acid composition of SM was clearly different from that of Cer. In virtually all samples the most abundant Cer species were those containing C24:0 and C24:1 in their N-acyl chains, while the main species contained in SM was C16:0. Brain was the most divergent tissue, in which Cer and SM C18:0 were very abundant.

Severe granulomatous hepatitis caused by Capillaria hepatica in a puppy

This report describes the inflammation caused by Capillaria hepatica in the liver of a female stray dog of approximately 2 months old for the first time in Turkey. Histopathological examination revealed severe granulomatous hepatitis with occasional adult nematodes and abundant eggs in the hepatic parenchyma. The present case differs from the other capillariasis cases by the age of the dog and the presence of mature female parasites and severe inflammation.

Hydrolysis of di(2-ethylhexyl) phthalate in humans, monkeys, dogs, rats, and mice: An in vitro analysis using liver and intestinal microsomes

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that is rapidly metabolized to mono(2-ethylhexyl) phthalate (MEHP), an active metabolite, in mammals. In the present study, the hydrolysis of DEHP by the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice was examined. The kinetics of liver microsomes fit the Michaelis-Menten model for humans, monkeys, and rats, and the Hill model for dogs and mice. Km or S50 values were similar among species, whereas Vmax exhibited species differences of approximately 9-fold. CLint or CLmax values were in the order of mice > dogs > monkeys ≥ rats > humans. Hydrolytic activity towards DEHP was not detected in the intestinal microsomes of humans or dogs. The kinetics of monkeys, rats, and mice followed the Hill model. In comparisons of the liver microsomes of each species, S50 values were similar, while Vmax and CLmax values (mice > rats > monkeys) were considerably lower (approximately 5–25%). These results suggest that hydrolytic activity towards DEHP in the liver and intestines markedly differ among humans and non-rodent and rodent experimental animals, and imply that species differences are closely associated with the toxicity of DEHP.

Identification of canine cytochrome P-450s (CYPs) metabolizing the tramadol (+)-M1 and (+)-M2 metabolites to the tramadol (+)-M5 metabolite in dog liver microsomes.

We previously showed that (+)-tramadol is metabolized in dog liver to (+)-M1 exclusively by CYP2D15 and to (+)-M2 by multiple CYPs, but primarily CYP2B11. However, (+)-M1 and (+)-M2 are further metabolized in dogs to (+)-M5, which is the major metabolite found in dog plasma and urine. In this study, we identified canine CYPs involved in metabolizing (+)-M1 and (+)-M2 using recombinant enzymes, untreated dog liver microsomes (DLMs), inhibitor-treated DLMs, and DLMs from CYP inducer-treated dogs. A canine P-glycoprotein expressing cell line was also used to evaluate whether (+)-tramadol, (+)-M1, (+)-M2, or (+)-M5 are substrates of canine P-glycoprotein, thereby limiting their distribution into the central nervous system. (+)-M5 was largely formed from (+)-M1 by recombinant CYP2C21 with minor contributions from CYP2C41 and CYP2B11. (+)-M5 formation in DLMs from (+)-M1 was potently inhibited by sulfaphenazole (CYP2C inhibitor) and chloramphenicol (CYP2B11 inhibitor) and was greatly increased in DLMs from phenobarbital-treated dogs. (+)-M5 was formed from (+)-M2 predominantly by CYP2D15. (+)-M5 formation from (+)-M1 in DLMs was potently inhibited by quinidine (CYP2D inhibitor) but had only a minor impact from all CYP inducers tested. Intrinsic clearance estimates showed over 50 times higher values for (+)-M5 formation from (+)-M2 compared with (+)-M1 in DLMs. This was largely attributed to the higher enzyme affinity (lower Km) for (+)-M2 compared with (+)-M1 as substrate. (+)-tramadol, (+)-M1, (+)-M2, or (+)-M5 were not p-glycoprotein substrates. This study provides a clearer picture of the role of individual CYPs in the complex metabolism of tramadol in dogs.