Hepatic and Plasma Endothelin-1 in Dogs with Chronic Hepatitis

Complications of Liver Disease

Hepatobiliary disease in dogs and cats can lead to various complications. Vomiting is a common clinical sign in liver disease, and antiemetic therapy should be considered on a case-by-case basis. Ascites is managed by feeding a moderate sodium diet, therapy with spironolactone, and judicious use of furosemide. Hepatic encephalopathy is managed by feeding an appropriate diet and treating with lactulose and possibly an antimicrobial. Because coagulant and anticoagulant factors are affected in patients with hepatic dysfunction, they may be in an altered but balanced hemostatic state. This balance is fragile and bleeding or thrombosis can occur if it is disrupted.

Prognostic indicators in dogs with intra-hepatic portal hypertension

Objectives

The primary goals of this retrospective study were to describe a population of dogs with portal hypertension secondary to liver disease, and to assess whether prognosis could be inferred from historical, clinical, and clinicopathological data.

Animals and procedures

Dogs (N = 76) diagnosed with intrahepatic portal hypertension between 2011 and 2020 were included; dogs with known congenital hepatic anomalies were excluded. Effect on survival was assessed using univariable and multivariable Cox proportional hazards models for historical, clinical, and clinicopathological variables.

Results

Dogs survived for a median of 14 d (range: 0 to 2028 d), with 31.6% being euthanized within 2 d of diagnosis and 23.7% surviving longer than 2 mo. Presence of jaundice and duration of clinical signs, expressed in days, were significantly associated with outcome in the univariable analysis (HR = 1.846, 95% CI: 1.094 to 3.117, P = 0.02; HR = 0.995, 95% CI: 0.990 to 1.000, P = 0.033, respectively). However, only presence of jaundice was significantly associated with increased hazard of death in the multivariable analysis.

Conclusion

Results of this study show that portal hypertension is associated with a poor prognosis; however, some dogs can show prolonged survival.

Clinical relevance

Clinical data can guide decision-making for clinicians and owners.

Effect of a Weight Loss Program on Biochemical and Immunological Profile, Serum Leptin Levels, and Cardiovascular Parameters in Obese Dogs

This study aimed to investigate the effects of a weight loss program (WLP) on biochemical and immunological profile, and cardiovascular parameters in a cohort of dogs with naturally occurring obesity. Eleven obese dogs [body condition scoring (BCS), ≥7/9] were enrolled into the study and underwent clinical and cardiovascular examination, and blood testing before (T0) and after 6 months (T1) of WLP. Eleven normal weight (BCS, 4/5) healthy dogs were used as a control (CTR) group. Compared to the CTR group, at T0 obese dogs expressed higher serum leptin concentrations (p < 0.0005) that significantly decreased after weight loss (p < 0.005) but remained higher than the CTR group. Furthermore, obese dogs showed considerably lower levels (p < 0.0005) of regulatory T cell (Treg) compared to the CTR group, but they did not change after weight loss at T1. In obese dogs, tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations were substantially reduced at T1 (p < 0.0001 and p < 0.005). Regarding the cardiovascular parameters, only one obese dog was hypertensive at T0, and systolic blood pressure values showed no significant differences at the end of the WLP. The ratio of interventricular septal thickness in diastole to left ventricle internal diameter in diastole (IVSd/LVIDd) was significantly greater in obese dogs at T0 than in the CTR group (p < 0.005). It decreased after weight loss (p < 0.05). In obese dogs, troponin I level significantly reduced with weight loss (p < 0.05), while endothelin-1 level did not differ statistically. The results suggest that the immune dysregulation in the presence of high leptin levels and reduced number of Treg could affect obese dogs as well as humans. Based on our findings, we may speculate that a more complete immune-regulation restore could be obtained by a greater reduction in fat mass and a longer-term WLP. Finally, left ventricular remodeling may occur in some obese dogs. However, in canine species, further studies are needed to investigate the impact of obesity and related WLP on cardiovascular system.

Plasma renin activity and aldosterone concentration in dogs with acquired portosystemic collaterals

Background

The renin‐angiotensin‐aldosterone system (RAAS) is activated in humans with portal hypertension (PH) associated with liver disease. However, involvement of RAAS in dogs with intrahepatic PH is not clear.

Objective

To measure plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in dogs with PH (chronic hepatitis [CH] and primary hypoplasia of the portal vein [PHPV]), dogs with extrahepatic congenital portosystemic shunt (EH‐CPSS), and healthy dogs and to determine whether the RAAS is activated in dogs with PH.

Animals

Twenty‐seven dogs with acquired portosystemic collaterals (APSCs; 15 dogs with CH, 12 dogs with PHPV), 9 dogs with EH‐CPSS, and 10 healthy dogs.

Methods

Retrospective study. Plasma renin activity and PAC were measured by radioimmunoassay.

Results

Plasma renin activity was significantly higher in the CH group (median, 4.4 ng/mL/h) than in the EH‐CPSS (median, 1.0 ng/mL/h; P < .01) and the healthy (median, 1.1 ng/mL/h; P < .01) groups. No significant differences were found between the PHPV group (median, 2.2 ng/mL/h) and other groups. Plasma aldosterone concentration was significantly higher in the CH (median, 111.0 pg/mL) and PHPV (median, 89.5 pg/mL) groups than in the EH‐CPSS (median, 1.0 pg/mL; P < .001, P < .01, respectively) and healthy (median, 14.5 pg/mL; P < .001, P < .05, respectively) groups.

Conclusions and Clinical Importance

Activation of the RAAS contributes to the pathophysiology of intrahepatic PH in dogs, suggesting that spironolactone may not only be effective for the treatment of ascites but also for the suppression of intrahepatic PH.

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.

Gallbladder Agenesis in 17 Dogs: 2006-2016

Background

Gallbladder agenesis (GBA) is extremely rare in dogs.

Hypothesis/Objectives

To describe the history, clinical signs, diagnosis, treatment, and outcomes of dogs with GBA.

Animals

Seventeen client‐owned dogs with GBA.

Methods

Medical records from 2006 through 2016 were retrospectively reviewed. Dogs were included when GBA was suspected on abdominal ultrasonography and confirmed by gross evaluation. Signalment, clinical signs, clinicopathological data, diagnostic imaging, histopathology, treatment, and outcome were recorded.

Results

Dogs were of 6 different breeds, and Chihuahuas (10 of 17) were most common. Median age at presentation was 1.9 (range, 0.7–7.4) years. Clinical signs included vomiting (5 of 17), anorexia (2 of 17), ascites (2 of 17), diarrhea (1 of 17), lethargy (1 of 17), and seizures (1 of 17). All dogs had increased serum activity of at least 1 liver enzyme, most commonly alanine aminotransferase (15 of 17). Fifteen dogs underwent computed tomography (CT) cholangiography; common bile duct (CBD) dilatation was confirmed in 12, without evidence of bile duct obstruction. Gross evaluation confirmed malformation of the liver lobes in 14 of 17 dogs and acquired portosystemic collaterals in 5 of 17. Ductal plate malformation was confirmed histologically in 16 of 17 dogs. During follow‐up (range, 4–3,379 days), 16 of 17 dogs remained alive.

Conclusions and Clinical Importance

Dogs with GBA exhibit clinicopathological signs of hepatobiliary injury and hepatic histopathological changes consistent with a ductal plate abnormality. Computed tomography cholangiography was superior to ultrasound examination in identifying accompanying nonobstructive CBD distention. Computed tomography cholangiography combined with laparoscopic liver biopsy is the preferable approach to characterize the full disease spectrum accompanying GBA in dogs.

Hepatic Fibrosis in Dogs

Hepatic fibrosis is commonly diagnosed in dogs, often as a sequela to chronic hepatitis (CH). The development of fibrosis is a crucial event in the progression of hepatic disease that is of prognostic value. The pathophysiology of hepatic fibrosis in human patients and rodent models has been studied extensively. Although less is known about this process in dogs, evidence suggests that fibrogenic mechanisms are similar between species and that activation of hepatic stellate cells is a key step. Diagnosis and staging of hepatic fibrosis in dogs requires histopathological examination of a liver biopsy specimen. However, performing a liver biopsy is invasive and assessment of fibrotic stage is complicated by the absence of a universally accepted staging scheme in veterinary medicine. Serum biomarkers that can discriminate among different fibrosis stages are used in human patients, but such markers must be more completely evaluated in dogs before clinical use. When successful treatment of its underlying cause is feasible, reversal of hepatic fibrosis has been shown to be possible in rodent models and human patients. Reversal of fibrosis has not been well documented in dogs, but successful treatment of CH is possible. In human medicine, better understanding of the pathomechanisms of hepatic fibrosis is leading to the development of novel treatment strategies. In time, these may be applied to dogs. This article comparatively reviews the pathogenesis of hepatic fibrosis, its diagnosis, and its treatment in dogs.

Portal Vein/Aorta Ratio in Dogs with Acquired Portosystemic Collaterals

BACKGROUND

The portal vein (PV) diameter increases in humans with portal hypertension (PH). However, there is no evidence of PV enlargement in dogs with PH.

OBJECTIVES

To measure the PV-to-aorta (PV/Ao) ratio in dogs with PH (chronic hepatitis [CH], primary hypoplasia of the PV [PHPV]), in dogs with extrahepatic congenital portosystemic shunt (EH-CPSS), and in healthy dogs, and to evaluate the relationship between PV/Ao ratio and splenic pulp pressure (SPP).

ANIMALS

Twenty-five dogs with acquired portosystemic collaterals (APSCs; 15 with CH, 10 with PHPV), 32 dogs with EH-CPSS, and 20 healthy dogs.

METHODS

Retrospective study. The PV/Ao ratio was calculated with images obtained by computed tomography. SPP was measured at the time of liver biopsy in 45 dogs.

RESULTS

Median PV/Ao ratio was similar between dogs with CH (1.35, range 1.05-2.01) and healthy dogs (0.95, 0.80-1.15), but differed significantly between the CH group and both the PHPV (0.40, 0.24-0.67) and EH-CPSS groups (0.30, 0.11-0.64) (P < .001). The PV/Ao ratio was significantly lower in the PHPV group than in healthy dogs (P < .05). It also correlated positively with SPP (r_s = 0.71; P < .001). However, there was no intragroup correlation between SPP and the PV/Ao ratio in any group.

CONCLUSIONS AND CLINICAL IMPORTANCE

The PV/Ao ratio can be evaluated in dogs with APSCs on computed tomography. Further studies are needed to examine the relationship between SPP and the PV/Ao ratio in larger groups of dogs with PH and to determine its clinical relevance.

Portal Vein/Aorta Ratio in Dogs with Acquired Portosystemic Collaterals

Background

The portal vein (PV) diameter increases in humans with portal hypertension (PH). However, there is no evidence of PV enlargement in dogs with PH.

Objectives

To measure the PV‐to‐aorta (PV/Ao) ratio in dogs with PH (chronic hepatitis [CH], primary hypoplasia of the PV [PHPV]), in dogs with extrahepatic congenital portosystemic shunt (EH‐CPSS), and in healthy dogs, and to evaluate the relationship between PV/Ao ratio and splenic pulp pressure (SPP).

Animals

Twenty‐five dogs with acquired portosystemic collaterals (APSCs; 15 with CH, 10 with PHPV), 32 dogs with EH‐CPSS, and 20 healthy dogs.

Methods

Retrospective study. The PV/Ao ratio was calculated with images obtained by computed tomography. SPP was measured at the time of liver biopsy in 45 dogs.

Results

Median PV/Ao ratio was similar between dogs with CH (1.35, range 1.05–2.01) and healthy dogs (0.95, 0.80–1.15), but differed significantly between the CH group and both the PHPV (0.40, 0.24–0.67) and EH‐CPSS groups (0.30, 0.11–0.64) (P < .001). The PV/Ao ratio was significantly lower in the PHPV group than in healthy dogs (P < .05). It also correlated positively with SPP (r_s = 0.71; P < .001). However, there was no intragroup correlation between SPP and the PV/Ao ratio in any group.

Conclusions and Clinical Importance

The PV/Ao ratio can be evaluated in dogs with APSCs on computed tomography. Further studies are needed to examine the relationship between SPP and the PV/Ao ratio in larger groups of dogs with PH and to determine its clinical relevance.