Exploratory study on the endogenous ouabain in idiopathic pulmonary arterial hypertension patients

Introduction. Endogenous ouabain (EO) is a steroid hormone secreted by the adrenal glands associated with adverse cardiovascular outcomes. However, EO plays other roles as brain protection against traumatic injury and seems involved in the adaptive response to hypoxia. Recently, we detected, for the first time, EO in a healthy human group of acute hypoxia and diving animals. Methods. This study complements the above as we considered a human model of chronic hypoxia. The aim is to detect EO in five idiopathic pulmonary arterial hypertension patients. Results and Discussion. We found that these patients had higher plasma concentrations of EO than control subjects. In addition, EO plasma concentrations were negatively correlated with the mean pulmonary arterial pressure and total pulmonary vascular resistance. The results could suggest that high concentrations of EO are predictive of better adaptation of the right ventricular afterload. Conclusion. Although the results are preliminary, they can represent a helpful hint for future investigations for possible therapeutic and diagnostic approaches.