TGFB1 and atrial fibrillation: Relaxin-2 possesses a robust antifibrotic effect in the cardiovascular system1,2,6, and similarly to our results regarding Gal-3, it has been determined that AF patients with high relaxin-2 serum levels also showed an increase in serum levels of several fibrotic and inflammatory biomarkers such as TGF-β, PICP and TNF-α8.