IL-1β stimulation induced a significant but mild increase of mRNA expression of RANK in AF and NP cells (relative expression (vs. control): IL-1β 0.1 ng/mL: AF 2.0 ± 0.26, p < 0.01, NP 1.93 ± 0.23, p < 0.05; IL-1β 1.0 ng/mL: NP 2.66 ± 0.73, p < 0.05; IL-1β 10 ng/mL: AF 1.95 ± 0.27, p < 0.01) (Fig. 3a, b). This evidence concerns the gene TNFRSF11A and atrial fibrillation.