CCL2 and atrial fibrillation: After a 24 hour treatment, significant decreases were observed in the expression of VEGF (p = 0.0286), TNF-α (p = 0.0286) and IL-1β (p = 0.0286) and a trend of decreased expression in CCL2/MCP-1 (p = 0.057) in mast cells treated with healthy AF DCCM compared to untreated basal controls and degenerate AF DCCM, suggesting an inhibitory role for AF cells on mast cell phenotype (Fig. 5).