The protocol for histologic analyses has been described [6 (link)–10 (link)]. Briefly, all studies were performed on formalin-fixed, paraffin-embedded tissues. Four-μm-thick heart sections were subjected to Masson’s trichrome and picrosirius red staining according to the manufacturer’s recommendations (Sigma-Aldrich, St. Louis, MO). Immunohistochemistry staining was performed using specific antibodies against CD45 (Abcam, Cambridge, MA) with corresponding secondary antibodies and counterstained with DAPI (Thermo Fisher Scientific, Waltham, MA). Microscopic evaluation of labeled slides was performed using a NIKON Ti2 inverted microscope equipped with DS-Qi2 and DS-Fi3, and monochrome and color cameras, respectively.