Head-up tilt induced syncope and adenosine A2A receptor gene polymorphism.

Aims: High adenosine plasma levels and high expression of adenosine A(2A) receptors are observed in patients with unexplained syncope and a positive head-up tilt test (HUT). This study aimed to evaluate the single nucleotide polymorphism (SNP) (c.1364 T>C) which is the most commonly found polymorphism in the A(2A) receptor gene, in patients with unexplained syncope undergoing HUT.

Peripheral plasma adenosine release in patients with chronic heart failure.

Objective: Chronic heart failure (CHF) is accompanied by increased adenosine plasma levels (APLs). It is unknown whether adenosine release occurs at the peripheral level or whether the myocardium itself is the source of adenosine release. To answer this question, we evaluated APLs in the coronary sinus of CHF patients during a resynchronisation procedure and compared the values with those at the peripheral level.

Release of markers of myocardial damage evaluated in the coronary sinus during cardiac surgery.

Myocardial damage is a frequent complication of cardiac surgery by direct mechanical trauma during the surgical procedure and by myocardial ischemia, which occurs during the cardiopulmonary bypass (CBP). Because the concentrations of biomarkers in the blood collected from the coronary sinus are the best witness of the myocardial damages, we measured the levels of specific cardiac troponin I (c-TnI) and nonspecific (adenosine, myoglobin) markers of left ventricular damages in the coronary sinus of patients during cardiac surgery. Thirty patients who underwent aortic valve replacement for aortic stenosis were included.

Increased expression of adenosine A2A receptors in patients with spontaneous and head-up-tilt-induced syncope.

Background: Adenosine may play a role in the triggering of neurocardiogenic syncope, but no information on adenosine receptors is available at the present time.

Objective: The purpose of this study was to investigate whether adenosine A2A receptors expression is altered in patients with neurocardiogenic syncope.

Methods: Adenosine plasma levels (APLs), the expression of A2A receptors, were measured (mean +/- standard error of the mean) during tilt testing.

Relationship between A2A adenosine receptor expression and intradialytic hypotension during hemodialysis.

Background: Intradialytic hypotension (IDH) is a common complication of hemodialysis sessions (HDSs). Adenosine may contribute to the drop in blood pressure during IDH events because it has hypotensive effects. As A(2A) adenosine receptor expression is essential for blood pressure control, we compared the expression of A(2A) receptors (Bmax, K(D), and messenger ribonucleic acid [mRNA] levels) in peripheral blood mononuclear cells from IDH and non-IDH patients and from controls.