S100B: role in cardiac remodeling and function following myocardial infarction in diabetes

S100B plays a role in cardiac remodeling following myocardial infarction (MI) and in diabetic vascular complications but not examined in diabetic myocardium. We thus examined the effects of targeted deletion of S100B gene on post-MI hearts.

Coronary artery ligation or sham was performed 15 weeks after streptozotocin (STZ) or vehicle injection in wild-type (WT) and S100B knock-out (BKO) mice. Left ventricular (LV) structural and functional remodeling was studied 35 days after induction of MI.

In diabetes, post-MI remodeling exhibited an attenuated increase in LV mass, dilation, and myocyte hypertrophy in association with increased apoptosis and fibrosis and reduced matrix metalloproteinase-2 (MMP-2) activity. Despite reduced LV dilation, impairment of cardiac function was similar to non-diabetic controls. Both diabetes and MI alone induced myocardial S100B and its canonical receptor for advanced glycation end product (RAGE) expression. By contrast, in post-MI diabetic myocardium, S100B expression was attenuated. Diabetic BKO, following MI demonstrated increased ventricular dilation compared to WT, in association with greater impairment of cardiac function, GLUT4 expression and systemic AGE levels.

These data suggest that S100B expression may serve to modulate cardiac metabolism and adverse consequences of AGE in diabetic post-MI remodeling and function.