PRELIMINARY DATA ON THE ENDOGENOUS OUABAIN IN IDIOPATHIC PULMONARY ARTERIAL HYPERTENSION PATIENTS

Abstract

Objective: The aim is to detect the endogenous ouabain (EO) in idiopathic pulmonary arterial hypertension (IPAH) patients. Design and method: 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 (elite apnea divers) and in diving animals (common bottlenose dolphins, phocids and otariids, and loggerhead sea turtles). This study complements the above as we considered a human model of chronic hypoxia. We collected blood samples from five Caucasian males and measured EO with a Scintillation Proximity Assay. Results: We found that IPAH patients had higher plasma concentrations levels of EO than control subjects. In addition, EO plasma concentrations were negatively correlated with the mean pulmonary arterial pressure and total pulmonary vascular resistance (p-values <0.05). A positive correlation trend was observed with the cardiac index, a marker of healthy cardiac output. The results could suggest that high concentrations of EO are predictive of a better adaptation of the right ventricular afterload. Conclusions: Although these are preliminary results, they match data coming from other studies on clinical conditions that frequently occur in comorbidity with IPAH. It can represent a helpful hint for future investigations involving other pathological conditions for possible therapeutic and diagnostic approaches.