Effect of Pioglitazone on Mitochondrial Metabolism in Pulmonary Hypertension Due to Chronic Lung Disease

Pulmonary hypertension (PH) is a state of chronic elevated pressure in the pulmonary circulation. PH has multiple possible causes, clinically classified into 5 separate groups according to the World Symposium on PH classification scheme. PH is common in adults, with increasing prevalence with age, and is associated with significant symptom burden and mortality. In the U.S., approximately 1.5 million U.S. adults have PH, including 5-10% of people >65.

Metabolic abnormalities have been highlighted recently as contributing to PH pathogenesis, disease severity, and outcome. In pre-clinical studies, reduced mitochondrial metabolism (oxidative phosphorylation) and reliance on alternative metabolic pathways (glycolysis) have been shown to promote pulmonary vascular remodeling and PH. Mechanistic investigation has shown that reduced PPARγ activity in lung vascular cells is necessary and sufficient to cause cellular proliferation and dysfunction followed by PH, all of which can be reversed by available pharmacotherapies designed to activate PPARγ.

Metabolic changes have been demonstrated in 1) lung vessels from multiple PH animal models and 2) humans with PAH 3) right ventricle from humans with PAH, 4) skeletal muscle from humans with PAH, 5) circulating platelets from humans with PAH and PH due to left heart disease. Clinical trials of therapies that activate PPARγ have not been previously conducted in patients with PH but are believed by experts in the field to be a highly promising therapeutic approach.

In this trial, the investigators will study the mitochondrial metabolic effects ("bioenergetics") of pioglitazone, an available medication from the class of thiazolidinedione (TZD) drugs that activate PPARγ. This medication is FDA-approved for the treatment of Type II diabetes mellitus (DM). Pioglitazone has been studied in non-diabetics with diverse other conditions demonstrating safety.

The study team will assess cellular energy metabolism through a sophisticated assay of bioenergetics. The investigators and others have shown that bioenergetics can be measured in isolated platelets obtained from a peripheral blood draw in patients with PH and other diseases. Furthermore, others have shown that in PAH, platelet bioenergetics correlate with known disease-relevant metabolic changes in lung blood vessels. In this study, the team will assess the effect of pioglitazone on bioenergetic parameters in platelets isolated from whole blood samples.