Gene expression profiling of endomyocardial biopsies from dogs with dilated cardiomyopathy phenotype

The employment of advanced molecular biology technologies has expanded the diagnostic investigation of cardiomyopathies in dogs; these technologies have predominantly been performed on postmortem samples, although the recent use of endomyocardial biopsy in living dogs has enabled a better pre-mortem diagnostic approach to study the myocardial injury. Endomyocardial biopsies were collected in nine dogs with a dilated cardiomyopathy phenotype (DCM-p) and congestive heart failure and submitted to histologic examination, next generation sequencing (NGS) and polymerase chain reaction (PCR) analysis. Data from three healthy dogs (Fastq files) were retrieved from a previous approved study and used as a control group for ribonucleic acid sequencing. Histologic examination revealed endocardial fibrosis in 6/9 dogs, while lymphocytic interstitial infiltrates were detected in 2/9 dogs and lymphoplasmacytic and macrophage infiltrates were detected in 1/9. On PCR analysis, two dogs tested positive for canine parvovirus 2 and one dog for canine distemper virus. Gene expression pathways involved in cellular energy metabolism (especially carbohydrates-insulin) and cardiac structural proteins were different in all DCM-p dogs compared to control. When dogs with lymphocytic interstitial infiltrates were compared to the control group, NGS analysis revealed the predominant role of genes related to inflammation and pathogen infection. Next generation sequencing technology performed on in vivo endomyocardial biopsies, has identified different molecular and genetic factors that could play a role in the development and/or progression of DCM-p in dogs.