IL1B and atrial fibrillation: The mRNA level of RANKL was significantly upregulated by treatment with IL-1β (10 ng/mL) (relative expression (vs. control): RANKL in the AF 20.92 ± 5.12, p < 0.01; RANKL in the NP 40.16 ± 14.13, p < 0.01; RANKL in the CEP 45.33 ± 25.43, p < 0.05) (Fig. 4b, e, h).