Overexpression of Human C-Reactive Protein Exacerbates Left Ventricular Remodeling in Diabetic Cardiomyopathy

Abstract

C-reactive protein (CRP) is known to be a pathogenic agent in the cardiovascular system. However, the effect of CRP on heart failure has not been elucidated. The effect of human CRP on cardiac dysfunction induced by diabetes mellitus (DM) using human CRP-overexpressing transgenic mice (CRP-Tg) was examined. DM was induced in male wild-type mice (Wt/DM) and CRP-Tg (CRP/DM) by an injection of streptozotocin. Non-diabetic wild-type mice (Wt/Con) and CRP-Tg (CRP/Con) served as controls. Echocardiography and hemodynamic measurements 6 weeks after injection showed lower fractional shortening and left ventricular (LV) dP/dt max in CRP/DM compared with Wt/DM. Myocardial mRNA levels of interleukin-6, tumor necrosis factor-α, plasminogen activator inhibitor-1, angiotensin type 1 receptor, angiotensinogen, NADPH oxidase subunits (p47(phox), gp91(phox)), glutathione peroxidase-3. and connective tissue growth factor were increased in CRP/DM compared with Wt/DM. Nuclear staining of 8-hydroxydeoxyguanosine was also increased in CRP/DM compared with Wt/DM. CRP/DM was associated with increased terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling positive cells and a higher ratio of Bax/Bcl-2 proteins compared with Wt/DM. The extent of cardiac fibrosis assessed by Sirius red staining and immunohistochemical staining for collagen type 1 was significantly increased in CRP/DM compared with Wt/DM. Overexpression of human CRP exacerbates LV dysfunction and remodeling in diabetic cardiomyopathy, possibly through enhancement of the inflammation, renin-angiotensin system, and oxidative stress.