Fig. 1. ACTRIIA ligands activin A, GDF8, and GDF11 are expressed in the intima and media of small arterioles in human PAH and rat PH.
Immunohistochemical staining for activin A, GDF8, and GDF11 along with α-SMA costain performed on paraffin-embedded lung sections from healthy controls and patients with IPAH or HPAH (n = 5 each) and lung sections from control, MCT-exposed, or SU-Hx–exposed rats (n = 3 each). Horseradish peroxidase (HRP)–conjugated secondary antibody (3,3′-diaminobenzidine staining, as indicated by label HRP in brown) and α-smooth muscle actin (α-SMA) AP-conjugated primary antibody (as indicated by label SMA in blue; right) are shown. Scale bars, 50 μm.