Adenosine receptors mRNA expression in normal and failing minipig heart

Background: Chronic heart failure (HF) results in possibly beneficial endogenous adenosina accumulation. The final biological action of adenosine in a particular organ or cell population may depend on the relative expression level and signaling efficiency of the individual adenosine receptor (AR) subtypes. Aim: To determine myocardial expression of ARs, in the different chambers of failing compared to normal minipig hearts. Materials and Methods: Cardiac tissue (left and right atrium, left and right ventricle) was collected from male adult minipigs without (control, C, n¼5) and with pacing-induced HF (n¼5). ARs mRNA expression was evaluated by RT-PCR together with TNF–a mRNA expression. Results: A1R, A2AR, A2BR and A3R were expressed in all cardiac regions analyzed and, after 3 weeks of pacing, in left ventricle mRNA of each ARs resulted more expressed that in controls(A3R/gapdh: C¼0.2+0.07 vs. HF: 1.4+0.5 p¼0.03). TNF–a mRNA expression resulted significantly higher in left ventricle of HF pig (p¼0.009). We also observed a significant correlation between TNF–a mRNA expression and A1R (r¼0.6 p¼0.0002), A2AR (r¼0.8 p,0.0001), A2BR (r¼0.9 p,0.0001), A3R (r¼0.7 p,0.0001). Conclusion: ARs mRNA espression were characterized simultaneously in all cardiac chambers of normal and HF animals. All ARs, and expecially AR3 subtype, are expressed in all cardiac chambers and, compared to controls, overexpressed in left ventricle.