Serological testing for arrhythmogenic right ventricular cardiomyopathy in boxer dogs

: a naturally-occurring model of human disease

Abstract

This study aimed to investigate serum desmoglein-2 (DSG2) autoantibody as a potential specific biomarker of arrhythmogenic right ventricular cardiomyopathy (ARVC), as well as the relationship between echocardiographic and other variables, with ARVC in boxer dogs.

The study enrolled fifty-two boxer dogs, including seventeen healthy control dogs, ten dogs with occult ARVC, nineteen dogs with overt ARVC, and six dogs with other cardiac diseases. Twenty-one boxer dogs diagnosed with ARVC or other cardiac diseases at Langford Vets, University of Bristol, were retrospectively identified from the patient records. Thirty-one boxer dogs were prospectively recruited between March and November 2021, and tested with systolic blood pressure measurement, 3-minute electrocardiogram, echocardiogram, blood tests, and 24-hour Holter monitoring. Serum samples were obtained and delivered to the Labatt Family Heart Centre, University of Toronto in Canada for serum DSG2 autoantibody analysis using Western blot and ELISA techniques.

Statistical analysis revealed that overt dogs had significantly larger normalised systolic left ventricular internal diameter, left atrial-to-aortic root ratio (LA:Ao), and proximal right ventricular outflow tract diameter, as well as lower systolic blood pressure and fractional shortening, than the healthy dogs. The overt dogs had lower tricuspid annular systolic and late diastolic velocities than the occult dogs. The overt dogs also had greater white blood cell, neutrophil, and troponin I levels when compared to the healthy dogs. A cutoff value for LA:Ao of 1.455 was found to be the only significant independent predictor of ARVC. Except for one healthy dog, all dogs tested positive for serum DSG2 autoantibody. There was no significant difference in measurements between dogs with ARVC, other cardiac disease and apparently healthy controls. The study failed to demonstrate an association between serum DSG2 autoantibody positivity and boxer ARVC. A LA:Ao cutoff value of 1.455 may be useful in identifying boxer dogs with ARVC.

Date of Award	21 Mar 2023
Original language	English
Awarding Institution	University of Bristol
Supervisor	Melanie J Hezzell (Supervisor) & Eva Sammut (Supervisor)