Expression of BTK and TEC in the human heart, and the effect of ibrutinib on activation of the PI3K-Akt pathway in NRVM. (A) Gene expression of BTK and TEC in human atrial and ventricular tissue. Data are expressed as mean ± standard error of the mean. Atrial samples: sinus rhythm (N = 20), AF (N = 10); ventricle (N = 5). *P < .05. Unpaired Student t-test. Data obtained from microarray deposited at http://www.ncbi.nlm.nih.gov/geo/, accession number GSE2240. (B) The effect of ibrutinib treatment on PI3K(p110α) protein expression and/or pAkt/total Akt in NRVM under (1) basal conditions (top 2 panels), and (2) in the presence of insulin-like growth factor 1 (IGF1, 10 nM, +, bottom panel). A66 (10 µM), specific inhibitor of PI3K(p110α), was administered alone (top 2 panels) or together with IGF1 (bottom panel). Data are expressed as mean ± standard error of the mean of triplicates (under basal conditions, results are representative of 3 independent NRVM preparations). *P < .05 vs control (Con); #P < .05 vs IGF1. Analysis of variance followed by Fisher’s post-hoc tests. Ib, ibrutinib.