RT Journal Article SR Electronic T1 Effects of apoptosis signal- regulating kinase 1 (ASK1) inhibition in experimental pressure overload-induced right ventricular dysfunction JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA4913 DO 10.1183/13993003.congress-2015.PA4913 VO 46 IS suppl 59 A1 Mario Boehm A1 Baktybek Kojonazarov A1 Hossein Ardeschir Ghofrani A1 Friedrich Grimminger A1 Norbert Weissmann A1 John T. Liles A1 Grant R. Budas A1 Werner Seeger A1 Ralph T. Schermuly YR 2015 UL http://erj.ersjournals.com/content/46/suppl_59/PA4913.abstract AB Introduction: Apoptosis signal-regulating kinase 1 (ASK1) is a redox-sensitive kinase that acts through activation of p38 and c-Jun N-terminal kinase (JNK) pathways. However, the role of ASK1 in the pathogenesis of right ventricular (RV) remodeling and dysfunction is unknown. We sought to investigate the effects of the selective ASK1 inhibitor GS-444217 on pressure overload-induced RV remodeling.Methods: The effects of GS-444217 were evaluated in mice subjected to pulmonary artery banding (PAB) or sham operation. Seven days after surgery, PAB-challenged mice were randomized and treated either with placebo or GS-444217 for 14 days. RV function and remodeling were determined using echocardiography along with invasive hemodynamic measurements. Total RV collagen content was assessed by Picro-sirius red staining.Results: After 21 days, PAB resulted in right heart hypertrophy, reduced cardiac output and RV fibrosis. Animals treated with GS-444217 had increased cardiac output (14.98±1.21 ml/min vs. 10.81±0.72 ml/min, p<0.05), increased tricuspid annular plane systolic excursion (TAPSE) (1.28±0.06 mm vs. 0.96±0.06 mm, p<0.001) and reduced RV dilatation (1.96±0.02 mm vs. 2.23±0.05 mm, p<0.001), as compared with placebo treated mice. ASK1 inhibition did not significantly change RV systolic pressure or systemic arterial pressure. Improvements in RV function following ASK1 inhibition were accompanied by a robust decrease in RV fibrosis.Conclusions: ASK1 inhibition significantly attenuates RV dysfunction and fibrosis induced by PAB in mice. These results suggest that ASK1 plays a pathological role in RV remodeling and failure following chronic pressure overload.