SMAD3 and atrial fibrillation: Notably, in our Western Blot analysis, we found several Pro-fibrosis related proteins (TGF-β1, TGF-β2, P-Smad3, COL1A2, and COL1A3), which belong to TGF-β pathway, that showed gender-specific differences between NON-AF and LSP-AF group, with a significant up-regulation in the female LSP-AF group, but not in the male counterpart.