Right Ventricular Function and Oxidative Stress Improve with the Administration of Thyroid Hormones and Grape Juice in a Pulmonary Hypertension Model.

BACKGROUND

Adverse remodeling of lung vessels elevates pulmonary pressure and provokes pulmonary arterial hypertension (PAH). PAH results in increased right ventricle (RV) afterload, causing ventricular hypertrophy and the onset of heart failure. There is no specific treatment for maladaptive RV remodeling secondary to PAH.

OBJECTIVES

This study aims to explore two therapeutic approaches, grape juice (GJ) and thyroid hormones (TH), on PAH-induced oxidative stress and cardiac functional changes.

METHODS

Parameters of echocardiography related to lung vessel resistance (AT/ET ratio), RV contractility (TAPSE), and RV diastolic function (E/A peaks ratio) were evaluated. Also, total ROS, lipid peroxidation, antioxidant enzymes, calcium handling proteins, pro-oxidant and antioxidant protein expression were measured. Values of p<0.05 were considered statistically significant.

RESULTS

Both GJ and TH treatments demonstrated reductions in pulmonary resistance (22%) and improvements in TAPSE (inotropism ~11%) and AT/ET ratio (26%) (p<0.05). There were no changes amongst groups regarding the E/A peak ratio. Although ROS and TBARS were not statistically significant, GJ and TH treatments decreased xanthine oxidase (49%) levels and normalized HSP70 and calcium handling protein expression (p<0.05). However, only TH treatment ameliorated diastolic function (50%) and augmented NRF2 immunocontent (~48%) (p<0.05).

CONCLUSIONS

To the best of our knowledge, this study stands as a pioneer in showing that TH administered together with GJ promoted functional and biochemical improvements in a PAH model. Moreover, our data suggest that GJ and TH treatments were cardioprotective, combined or not, and exhibited their beneficial effects by modulating oxidative stress and calcium-handling proteins.