Gallbladder mucocele, cholelithiasis, choledocholithiasis, and cholecystitis are significant contributors to morbidity and mortality in dogs. The exact etiology of these conditions remains poorly understood, though various factors, such as endocrinopathies, dyslipidemia, and impaired gallbladder motility, have been suggested as potential contributors. Surgical intervention has been described as the first choice of treatment when biliary rupture or obstruction is suspected; however, medical management may be an important part of therapeutic or preventative strategy. Reports of medical management typically involve the use of a choleretic used to stimulate the flow of bile into the duodenum or substances that act as a “hepatoprotective” agent such as S-adenosylmethionine. In people, some nutrients appear to modify bile flow and are used as agents in the prevention and treatment of these conditions in the gallbladder. This paper provides a review of the literature about possible nutritional factors involved in the pathogenesis and treatment of canine gallbladder mucocele and cholelithiasis. Opportunities for the prevention and treatment of common biliary diseases in dogs may include the reduction of dietary fat, control of hyperlipidemia with omega-3 and fiber supplementation, ensuring an adequate supply of amino acids such as methionine and tryptophan, and the evaluation of vitamins such as vitamin D.

Objective: A commercially available Histoplasma urine antigen enzyme immunoassay (MV antigen EIA; MiraVista Diagnostics) is widely used to support the diagnosis of histoplasmosis in dogs; however, a standardized urine collection technique does not exist. The objective was to evaluate agreement between 3 urine collection techniques (free catch [FC], cystocentesis [cysto], and iatrogenically hospital-contaminated cystocentesis [contam]) using the MV antigen EIA in dogs and to determine associated false-positive rates (FPRs). Methods: Participants were 30 dogs suspected of histoplasmosis and 30 temporally matched, healthy controls. In this 12-month prospective study (December 2023 to 2024), 3 urine samples (FC, cysto, and contam) were collected within 24 hours from each dog. Agreement between methods was assessed using the McNemar test and Cohen κ coefficients. False-positive rates were calculated using clinical diagnosis as the reference standard. Results: 3 clinically ill dogs were definitively diagnosed with histoplasmosis. Agreement was substantial between cysto and contam samples (κ = 0.68; 95% CI, 0.39 to 0.97) and moderate between cysto and FC (κ = 0.45; 95% CI, 0.07 to 0.82) and FC and contam samples (κ = 0.42; 95% CI, 0.10 to 0.75). The overall FPR was 16% (9 of 57; 95% CI, 6 to 25%). The cysto samples had the lowest FPR (4% [2 of 57]; 95% CI, 1 to 12%), followed by FC (7% [4 of 57]; 95% CI, 3 to 17%) and contam (11% [6 of 57]; 95% CI, 5 to 21%). Conclusions: While all collection techniques demonstrated reasonable agreement, FC and contam samples were more prone to false positives. Clinical Relevance: Clinicians should confirm contam low-level positive results with sterile cysto to improve diagnostic accuracy and clinical decision-making for histoplasmosis in dogs.

Heterobilharzia americana is a trematode parasite that causes canine schistosomiasis, a disease capable of causing significant morbidity and mortality in dogs. Reliable diagnosis is essential for limiting disease progression. This study aimed to optimize and validate a previously developed TaqMan qPCR assay for detection of H. americana DNA in feces. The assay targets a highly repetitive non-coding DNA sequence located across multiple loci within the H. americana genome. PCR optimization involved gradient thermocycling and serial dilutions to refine annealing temperature and efficiency. PCR products were cloned and sequenced to confirm target specificity. Analytical sensitivity was assessed using serial two-fold dilutions of H. americana eggs spiked into feces and matrix-free samples, with PCR detection across replicates. Diagnostic sensitivity was assessed in 111 fecal samples from infected dogs using fecal sedimentation as gold standard. Analytical and diagnostic specificities were assessed by testing 54 fecal samples containing non-target parasites and 100 fecal samples from H. americana-uninfected dogs, respectively. Target specificity was confirmed by BLAST. Assay efficiency was 107 %. Matrix-dependent analytical sensitivity was 3 eggs/g feces (100 % replicates) and 1.5 eggs/g feces (60 % replicates); matrix-free sensitivity was 3 eggs/mL in saline. Diagnostic sensitivity was 98.2 % (95 % CI: 93.7-99.8 %). Both analytical and diagnostic specificities were 100 % (95 % CI: 93.6-100 % and 96.4-100 %, respectively). The assay demonstrated low intra-assay and inter-assay variability and minimal inter-operator variability across the dilution range tested. These findings support the optimized TaqMan qPCR assay as a highly sensitive and specific tool for detecting H. americana DNA in dog feces.

Objective: To determine whether microRNAs 122, 1275, 21, 222, and 181A serve as noninvasive biomarkers of canine chronic hepatitis (CH); can distinguish between dogs with idiopathic CH (iCH) and copper-associated CH (CuCH); and correlate with serum ALT activity, grade of inflammation, fibrosis, and degree of copper accumulation. Methods: From May 2019 through October 2023, dogs with CH, histologically characterized as either iCH or CuCH, and healthy control (HC) dogs without liver biopsies were enrolled in this prospective uncontrolled study. Serum samples were collected, and serum microRNAs were quantified by real-time quantitative PCR. Differences in gene fold expression between groups were calculated. Correlations between microRNA gene fold expression and serum ALT, hepatic copper quantification, grade of necroinflammatory activity, fibrosis, and histological copper score were assessed. Results: A total of 18 dogs with iCH, 14 dogs with CuCH, and 42 HC dogs were enrolled. No differences between iCH and CuCH dogs were observed for any microRNA. Differences between HC and overall CH dogs were observed for microRNAs 122, 1275, and 21. Positive correlations with serum ALT activity between microRNAs 122 and 21 were observed. Conclusions: None of the studied microRNAs were able to differentiate iCH from CuCH and only correlated with ALT activity. Serum microRNAs 122, 1275, and 21 appear to be nonspecific makers of hepatocellular injury. Clinical Relevance: Our results do not support the utility of these microRNAs as markers for distinguishing between iCH and CuCH in dogs.

Objective: To adapt and partially validate the accuracy and precision of serum exchangeable copper and 3-kDa ultrafiltered urinary copper concentrations as an analytical prerequisite to investigate the clinical utility of relative exchangeable copper and urinary small copper carrier-to-creatinine ratio as noninvasive biomarkers in dogs with copper-associated hepatitis. Methods: Serum exchangeable copper and 3-kDa ultrafiltered urinary copper concentrations of surplus samples of dogs submitted for diagnostic purposes from October 2023 through March 2024 were measured by adapting a previously described ultracentrifugation method. Copper concentrations were quantified using inductively coupled plasma mass spectrometry. The optimal relative centrifugal force was selected based on minimizing the variability among replicates. Analytical performance was evaluated through spike recovery and intra- and interassay repeatability. Results: Optimal parameters were identified as 5 g/L EDTA and 5,000 X g for serum exchangeable copper and 4,000 X g for 3-kDa ultrafiltered urinary copper. Spike recovery ranged from 97.9% to 108.5% for serum exchangeable copper and from 96.7% to 120% for ultrafiltered urinary copper. The median intra- and interassay coefficients of variation were 8.5% and 10.8% for exchangeable copper and 2.6% and 5.6% for ultrafiltered urinary copper, respectively. Conclusions: Ultrafiltration-based methods for measuring serum exchangeable copper and 3-kDa ultrafiltered urinary copper concentrations were successfully adapted for dogs, with spike recovery and intra- and interassay coefficients of variation within predefined acceptance criteria. Clinical Relevance: The results provide the analytical foundation for future investigation of the diagnostic utility of relative exchangeable copper and urinary small copper carrier protein as noninvasive biomarkers for copper-associated hepatitis in dogs.