SMAD3 and atrial fibrillation: Importantly, it is to mention that all significantly higher expressed proteins((TGF-β2, SMAD3 [10, 11], COL1A2, COL1A3 [12], PARP1 [13]) are pro-fibrosis-associated proteins and belong to or regulate the TGF-beta signaling pathway, suggesting that the TGF-β pathway plays a key role in promoting fibrosis remodeling in the female LSP-AF group.