Metabolic markers of myocardium insulin resistance in dogs with heart failure.

Background: Heart failure syndrome is an aspect of primary or secondary heart disease and is associated with decompensation, formation, and activation of pathological interactions between regulation systems. This results in myocardial energy metabolism alteration. This study was carried out to defy some metabolic aspects of myocardial tissue insulin resistance (IRM) development in canine heart failure.

Aim: To investigate the myocardial tissue concentration of adenosine triphosphate (ATP), glucose transporters 1 and 4, pyruvate dehydrogenase (PDH), hexokinase 2, insulin receptor (InsR), and adropin (ADR) protein and to screen metabolic changes and IRM in canine myocardium with heart failure.

Methods: We studied 28 dogs of different sexes, ages, and breeds. Groups were formed according to primary pathology: apparently healthy dogs (HD, = 6); dogs with CDVD (CDVDD, = 8); dogs with DCM (DCMD, = 6); and dogs with doxorubicin chemotherapy and doxorubicin-induced cardiomyopathy (DoxCMD, = 8). Animals in the study were diagnosed for primary disease by standard methods and algorithms. Animals were euthanized due to incurable neurological disease, refractory heart failure, or by owners will. The material was obtained immediately after death, fixed in liquid nitrogen, and stored in -80°C refrigerator. Studied proteins concentrations were analyzed in a specialized research laboratory, using ELISA kits, provided by Cloud-Clone Corp.

Results: ATP, GLUT1, and GLUT4 concentrations in myocardial tissue from the valvular disease group did not differ from the HD group. In CDVD, we found depression of PDH, hexokinase II (HX2), and ADR concentrations in comparison to HD. InsR was significantly lower in the CDVD and DoxCMD groups in comparison to the HD group, but in the DCM group, it was twofold higher than in the HD group. In the DCMD and DoxCMD groups, all parameters were lower than in the HD group. ATP, HX2, ADR, GLUT1, and GLUT4 were higher in the CDVD group, than in the DCM and DoxCM groups. PDH in the CDVD and DoxCM groups did not differ. PDH was depleted in the DCM to CDVD and DoxCM groups. InsR did not differ between the CDVD and DoxCM groups, but was upregulated in the DCM to CDVD and DoxCM groups.

Conclusion: Development of myocardial tissue IRM is a part of the structural, functional and metabolic remodeling in dogs with heart failure of different etiology. At the late stages, we found significant changes in energy supply availability and production in the myocardium.