PT - JOURNAL ARTICLE AU - Jose Gomez-Arroyo AU - Masahiro Sakagami AU - Aamer A. Syed AU - Laszlo Farkas AU - Benjamin Van Tassell AU - Donatas Kraskauskas AU - Shiro Mizuno AU - Antonio Abbate AU - Harm J. Bogaard AU - Peter R. Byron AU - Norbert F. Voelkel TI - Iloprost reverses established fibrosis in experimental right ventricular failure AID - 10.1183/09031936.00188013 DP - 2014 Jan 01 TA - European Respiratory Journal PG - erj01880-2013 4099 - http://erj.ersjournals.com/content/early/2014/09/26/09031936.00188013.short 4100 - http://erj.ersjournals.com/content/early/2014/09/26/09031936.00188013.full AB - Prostacyclin and its analogues improve cardiac output and functional capacity in patients with pulmonary arterial hypertension (PAH); however, the underlying mechanism is not fully understood. We hypothesised that prostanoids have load-independent beneficial effects on the right ventricle (RV). Angio-obliterative PAH and RV failure were induced in rats with a single injection of SU5416 followed by 4 weeks of exposure to hypoxia. Upon confirmation of RV dysfunction and PAH, rats were randomised to 0.1 μg·kg−1 nebulised iloprost or drug-free vehicle, three times daily for 2 weeks. RV function and treadmill running time were evaluated pre- and post-iloprost/vehicle treatment. Pulmonary artery banded rats were treated 8 weeks after surgery to allow for significant RV hypertrophy. Inhaled iloprost significantly improved tricuspid annulus plane systolic excursion and increased exercise capacity, while mean pulmonary artery pressure and the percentage of occluded pulmonary vessels remained unchanged. Rats treated with iloprost had a striking reduction in RV collagen deposition, procollagen mRNA levels and connective tissue growth factor expression in both SU5416/hypoxia and pulmonary artery banded rats. In vitro, cardiac fibroblasts treated with iloprost showed a reduction in transforming growth factor (TGF)-β1-induced connective tissue growth factor expression, in a protein kinase A-dependent manner. Iloprost decreased TGF-β1-induced procollagen mRNA expression as well as cardiac fibroblast activation and migration. Iloprost significantly induced metalloproteinase-9 gene expression and activity and increased the expression of autophagy genes associated with collagen degradation. Inhaled iloprost improves RV function and reverses established RV fibrosis partially by preventing collagen synthesis and by increasing collagen turnover. Prostanoids have load-independent effects on the right ventricle that could contribute to improvement in #PAH http://ow.ly/Ae5Om