INHBE and pulmonary arterial hypertension: The concentration of other circulating ligands, such as activins and growth and differentiation factors (GDFs), which also interact through the TGF-β receptor family, is also increased in PAH, which probably stimulates growth cells, and thus contributes to the remodelling of pulmonary vessels and is an additional pathomechanism for the development of pulmonary hypertension [10].