Although cell fusion between rCMs and MSCs was detectable, the very low frequency (0.7%) could not account for the phenotype of the GFP ؉ MSCs. In conclusion, we have identified an MSC population displaying plasticity toward the cardiomyocyte lineage while retaining mesenchymal stromal cell properties, including a nonexcitable electrophysiological phenotype. The demonstration of an MSC population coexpressing cardiac and stromal cell markers may explain conflicting results in the literature and indicates the need to better understand the effects of MSCs on myocardial injury. STEM

These findings indicate that the combination of enhanced tissue renin-angiotensin system and hyperglycaemia lead to the development of diabetic cardiomyopathy. Fibrosis, and myocyte hypertrophy, a prominent feature of this model, may be a consequence of activation of the pro-sclerotic cytokine, transforming growth factor-beta, by the diabetic state.

Background-Congestive heart failure (CHF) is a disease that is characterized by progressive left ventricular (LV) dysfunction and dilatation. Oxidative stress is thought to contribute to the progression of CHF, and antioxidants have been shown to have beneficial effects when started early after myocardial infarction (MI). In this study, we tested whether the powerful antioxidant probucol would attenuate progression of CHF once it was established after MI in the rat. Methods and Results-Ligation of a coronary artery was used to create an MI in rats (nϭ266). Survivors were then randomized 20 days after MI to either probucol 61 mg · kg Ϫ1 · d Ϫ1 or vehicle and followed up for a total of 100 days after MI. Studies of cardiac hemodynamics, LV remodeling, cardiac apoptosis and morphology, systemic neurohumoral activation, oxidative stress, and renal function were then evaluated. Probucol improved LV function (LV maximum rate of pressure rise from 3103 to 4250 mm Hg/s, PϽ0.05, and LV end-diastolic pressure decrease from 28 to 24 mm Hg, PϽ0.05), reduced pulmonary weights, prevented right ventricular systolic hypertension, and preserved renal function compared with vehicle. Probucol also prevented LV dilatation, prevented wall thinning (1.70 versus 1.42 mm, PϽ0.05), reduced cardiac fibrosis and cardiac apoptosis, attenuated increased myocardial cell cross-sectional area, and increased scar thickness. Conclusions-In