Myocardial inflammation in experimental acute right ventricular failure: Effects of prostacyclin therapy

Background: Acute transient pulmonary hypertension may induce a state of persistent right ventricular (RV) failure. We hypothesized that this could be related to an activation of inflammatory processes and reduced by prostacyclin therapy.

Methods: Sixteen dogs were assigned to a 90-minute pulmonary artery banding (n = 8), or to a sham operation (n = 8). Hemodynamic variables were measured 30 minutes after banding release. This was repeated in 7 dogs with pulmonary artery banding-induced RV failure, followed by a 60-minute epoprostenol infusion. After euthanasia of the animals, myocardial tissue was sampled.

Results: Persistent RV failure was associated with increased myocardial expression of interleukin (IL)-1β, IL-6, monocyte chemoattractant protein 1, pro-inflammatory IL-6/IL-10, and neutrophil and macrophage infiltration, whereas heme oxygenase 1 expression was decreased. These changes were observed in RV and to a lesser extent in the left ventricle (LV). In the RV only, expressions of prostacyclin synthase and anti-inflammatory IL-10 and IL-33 decreased and vascular cell adhesion molecule expression increased, whereas macrophage inflammatory protein-1α and intercellular adhesion molecule 1 expressions remained unchanged. After epoprostenol infusion, there was decreased expression of IL-1β, macrophage inflammatory protein-1α, and vascular cell adhesion molecule 1 and increased IL-10 expression in the RV and the LV, whereas monocyte chemoattractant protein-1 decreased in the RV only. Epoprostenol infusion resulted in decreased RV IL-6/IL-10 and pro-apoptotic Bax/Bcl-2, together with decreased RV neutrophil and RV and LV macrophage infiltration. The RV ratio of end systolic-to-pulmonary arterial elastances was inversely correlated to RV IL-6/IL-10, macrophage, and neutrophil infiltration, and to RV heme oxygenase-1 and IL-33 expression.

Conclusions: Acute afterload-induced persistent RV failure is associated with an activation of inflammatory processes, which are limited by epoprostenol.