Objective—To compare the degree of mRNA expression for matrix metalloproteinases (MMPs), tissue inhibitors (TIMPs), and lysyl oxidase in myocardial samples from dogs with cardiac and systemic diseases and from healthy control dogs.
Sample—Myocardial samples from the atria, ventricles, and septum of 8 control dogs, 6 dogs with systemic diseases, 4 dogs with dilated cardiomyopathy (DCM), and 5 dogs with other cardiac diseases.
Procedures—Degrees of mRNA expression for MMP-1, -2, -3, -9, and -13; TIMP-1, -2, -3, and -4; and lysyl oxidase were measured via quantitative real-time PCR assay. Histologic examination of the hearts was performed to identify pathological changes.
Results—In myocardial samples from control dogs, only TIMP-3 and TIMP-4 mRNA expression was detected, with a significantly higher degree in male versus female dogs. In dogs with systemic and cardiac diseases, all investigated markers were expressed, with a significantly higher degree of mRNA expression than in control dogs. Furthermore, the degree of expression for MMP-2, TIMP-1, and TIMP-2 was significantly higher in dogs with DCM than in dogs with systemic diseases and cardiac diseases other than DCM. Expression was generally greater in atrial than in ventricular tissue for MMP-2, MMP-13, and lysyl oxidase in samples from dogs with atrial fibrillation.
Conclusions and Clinical Relevance—Degrees of myocardial MMP, TIMP, and lysyl oxidase mRNA expression were higher in dogs with cardiac and systemic diseases than in healthy dogs, suggesting that expression of these markers is a nonspecific consequence of end-stage diseases. Selective differences in the expression of some markers may reflect specific pathogenic mechanisms and may play a role in disease progression, morbidity and mortality rates, and treatment response.
Objective—To compare myocardial cytokine expression in dogs with naturally occurring cardiac or systemic diseases and dogs without cardiac or systemic diseases (control dogs)
Sample—Myocardial tissue samples from 7 systemic disease-affected dogs (SDDs), 7 cardiac disease-affected dogs (CDDs), and 8 control dogs.
Procedures—mRNA expression of interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, transforming growth factor (TGF)-β1, TGF-β2, TGF-β3, and growth differentiation factor-15 in myocardial tissue samples obtained from CDDs, SDDs, and control dogs were analyzed via quantitative PCR assays.
Results—In control dogs, only mRNA for TNF-α, TGF-β1, and TGF-β3 was detected; concentrations were significantly higher in male than in female dogs. In SDDs and CDDs, all cytokines, growth factors, and growth differentiation factor-15 were expressed. Compared with findings in SDDs, IL-1, IL-6, IL-8, IL-10, TNF-α, and IFN-γ expression was significantly increased in CDDs; specifically, IL-1, IL-8, TNF-α, TGF-β1, and TGF-β3 expression was increased in the atria and IL-8, IL-10, TNF-α, and IFN-γ expression was increased in the ventricles of CDDs.
Conclusions and Clinical Relevance—Data suggested that the alterations in cytokine expression in SDDs and CDDs, compared with control dog findings, were a result of inflammatory system activation. The differences in cytokine expression in atria and ventricles between SDDs and CDDs were suggestive of different remodeling processes. A better knowledge of myocardial involvement in SDDs and of immune regulation in CDDs might beneficially affect morbidity and mortality rates and provide new treatment approaches.