Peripheral markers of oxidative stress in Labrador retrievers with copper-associated hepatitis

Oxidative Stress in Canine Diseases: A Comprehensive Review

Oxidative stress (OS), defined as a disruption in redox balance favoring oxidants, has emerged as a major contributor to numerous diseases in human and veterinary medicine. While several reviews have explored the implication of OS in human pathology, an exhaustive review of the canine species is lacking. This comprehensive review aims to summarize the existing literature on the role of OS in canine diseases, highlighting its potentially detrimental effect on various organs and systems. Some inconsistencies among studies exist, likely due to varying biomarkers and sample types. However, there is substantial evidence supporting the involvement of OS in the development or progression of numerous canine disorders, such as cardiovascular, oncologic, endocrine, gastrointestinal, hematologic, renal, neurologic, infectious, and parasitic diseases, among others. Additionally, this review discusses the efficacy of antioxidant and pro-oxidant therapeutic agents for these conditions. Dietary interventions to counteract OS in dogs have gained significant attention in recent years, although further research on the topic is needed. This review aims to serve as a foundational resource for future investigations in this promising field.

Peripheral biomarkers of oxidative stress in dogs with acute pancreatitis

BACKGROUND

Oxidative stress is considered a pathomechanism of acute pancreatitis (AP), but no studies have extensively characterized oxidant status in dogs with naturally-occurring AP.

HYPOTHESIS OR OBJECTIVES

Evaluate measures of oxidant status in dogs with AP and explore whether these measures correlate with AP severity.

ANIMALS

Fifteen dogs with AP and 9 control dogs.

METHODS

Prospective, controlled observational study. Plasma reactive metabolite (RM) concentrations, antioxidant potential (AOP), and urinary F₂ isoprostane concentrations were measured in AP dogs and healthy controls. Severity of AP was assessed by length of hospitalization and 3 disease severity indices: canine acute pancreatitis severity (CAPS), modified canine activity index (M-CAI), and the acute patient physiologic and laboratory evaluation score (APPLE_full ).

RESULTS

Reactive metabolite (RM) concentrations (median, 65 relative fluorescent units [RFU]/μL; range, 20-331 RFU/μL) and RM:AOP (median, 7; range, 4-109) were higher in AP dogs than healthy controls (median RM, 25 RFU/μL; range, 16-41 RFU/μL; median RM:AOP, 4; range, 2-7; P < .001 for both comparisons). Reactive metabolite (r_S  = 0.603, P = .08) and RM:AOP (r_S  = 0.491, P = .06) were not correlated with the duration of hospitalization or disease severity indices evaluated. However, disease severity indices did not predict mortality in our study. Normalized urine 2,3-dinor-8-iso-prostaglandin F2α concentrations were correlated with C-reactive protein (CRP; r_S  = 0.491, P = .03), canine specific pancreatic lipase (Spec cPL; r_S  = 0.746, P = .002), and CAPS (r_S  = 0.603, P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Oxidant status is altered in dogs with naturally occurring AP, but the clinical relevance of this finding is unknown.

ATP7A, ATP7B, and RETN genotypes in Labrador Retrievers with and without copper-associated hepatopathy

OBJECTIVE

To determine the frequency of previously reported coding variants in the ATP7A, ATP7B, and RETN genes in a US population of Labrador Retrievers and to explore potential associations of these genotypes with pathologic hepatic copper accumulation.

SAMPLE

Archived hepatic specimens from 90 Labrador Retrievers collected between 2013 and 2021.

PROCEDURES

The Michigan State University Veterinary Diagnostic Laboratory database was searched to identify archived tissues from Labrador Retrievers that had undergone hepatic histopathologic assessment. Cases were classified into control, copper-associated hepatopathy (CAH), and intermediate populations on the basis of histopathologic features and hepatic copper accumulation. The DNA was extracted from archived tissues and genotyped for reported variants in the 3 genes. Allele frequencies were determined, and associations of genotypes with CAH status were evaluated.

RESULTS

29 control dogs, 45 CAH dogs, and 16 intermediate dogs were included in the study. The overall ATP7A and RETN variant allele frequencies were 30% and 13%, respectively, and were not significantly different among control, CAH, and intermediate populations. The ATP7B variant allele frequency was significantly higher in the CAH population (30%) as compared to the control population (13%). However, 21 of 45 (47%) CAH dogs did not have an ATP7B variant allele whereas 7 of 28 (25%) control dogs did have an ATP7B variant allele.

CLINICAL RELEVANCE

Study results supported a contributory role for the ATP7B variant in CAH pathogenesis in Labrador Retrievers. However, the application of genetic testing in a clinical setting is complicated by genotypic variability within healthy and diseased dogs.