Roles of transglutaminases in cardiac and vascular diseases.

All transglutaminases share the common enzymatic activity of transamidation, or the cross-linking of glutamine and lysine residues to form N epsilon (gamma-glutamyl) lysyl isopeptide bonds. The plasma proenzyme factor XIII is responsible for stabilizing the fibrin clot against physical and fibrinolytic disruption. Another member of the transglutaminase family, tissue transglutaminase or TG2 is abundantly expressed in cardiomyocytes, vascular cells and macrophages.

Nicotine upregulates the expression of P2Y12 on vascular cells and megakaryoblasts.

Background: P2Y12 is the major platelet receptor that mediates ADP-induced aggregation. P2Y12 is also expressed by vascular cells. The factors that regulate P2Y12 expression have not been determined.

Safety of abciximab administration during PCI of patients with previous stroke.

Objectives: To examine the frequency of cerebrovascular complications among patients receiving abciximab (AB) undergoing PCI with prior intracranial hemorrhage (ICH) or recent (< 2 years) ischemic strokes.

Background: AB improves clinical outcomes in high-risk patients undergoing percutaneous coronary intervention (PCI); however, the safety of AB in patients with prior stroke has not been adequately studied.

Methods: A database review of 7,244 consecutive PCIs, from 7/97 to 10/01, identified 6,190 PCIs performed with AB among which 515 interventions were performed in patients with prior stroke history [ICH or recent ischemic stroke, (n = 101) and remote (> 2 years) ischemic stroke, (n = 414)].

Relation of serum levels of mast cell tryptase of left ventricular systolic function, left ventricular volume or congestive heart failure.

Background: Activated mast cells (MC) present in the myocardium of patients with cardiomyopathy may contribute to left ventricular dilatation and systolic dysfunction. We sought to determine whether peripheral levels of tryptase, an MC-specific protease, are related to indices of left ventricular size and function, as well as congestive heart failure (CHF) or coronary artery disease (CAD).

Methods And Results: Serum tryptase was measured in 85 patients undergoing cardiac catheterization with left ventriculography and coronary angiography and examined in relation to left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), congestive heart failure (CHF), and angiographically evident CAD.