Figure 6

ICAM-1 (8–22) mediates decreased contractility. Before fibrinogen was added to activated cardiomyocytes, soluble intracellular adhesion molecule-1 (ICAM-1) (8–22) peptide, which binds fibrinogen at peptides 117–133, is added in excess to the fibrinogen. Activated cardiomyocytes incubated with fibrinogen alone demonstrate a 40% reduction in contractility. Pre-incubation of fibrinogen with the ICAM-1 (8–22) peptide results in competition between cardiomyocyte-expressed ICAM-1 and the ICAM-1 (8–22) peptide for the fibrinogen active site (117–133). Pre-incubation with the ICAM-1 (8–22) peptide abolishes the reduced contractility seen with fibrinogen alone, whereas pre-incubation with 'scrambled' ICAM-1 peptide had no effect. *p < 0.05 versus control. Fbg, fibrinogen.