RT Journal Article SR Electronic T1 Treprostinil inhibits the recruitment of bone marrow-derived circulating fibrocytes in chronic hypoxic pulmonary hypertension JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1302 OP 1314 DO 10.1183/09031936.00028009 VO 36 IS 6 A1 V.S. Nikam A1 R.T. Schermuly A1 R. Dumitrascu A1 N. Weissmann A1 G. Kwapiszewska A1 N. Morrell A1 W. Klepetko A1 L. Fink A1 W. Seeger A1 R. Voswinckel YR 2010 UL http://erj.ersjournals.com/content/36/6/1302.abstract AB A unique subpopulation of peripheral blood mononuclear cells that exhibit a parallel expression of haematopoietic and mesenchymal markers has been described as “circulating fibrocytes”. These cells were demonstrated to obtain a fibroblastic phenotype in tissues or cell culture and contribute to pulmonary fibrotic disorders and tissue remodelling processes. The aim of our study was to characterise the recruitment of circulating fibrocytes in vivo in the model of chronic hypoxic pulmonary hypertension in mice and to analyse the therapeutic effect of the stable prostacyclin analogue trepostinil with respect to this cell population. To track circulating fibrocytes in vivo, we transplanted wild-type mice with bone marrow from ubiquitously eGFP expressing mice and subjected them to chronic hypoxia. We observed significantly increased recruitment of circulating fibrocytes to the remodelled pulmonary resistance arteries in response to hypoxia. Treatment with treprostinil significantly reduced the recruitment of these cells compared to normoxic mice. Treprostinil also reduced right ventricular systolic pressure and slightly reduced the vascular remodelling but failed to reverse the right ventricular hypertrophy. In summary, we show that circulating fibrocytes contribute to hypoxic pulmonary vascular remodelling and may be specifically targeted by a prostacyclin analogue. Further investigations of cellular and paracrine mechanisms are warranted to decipher their role in pulmonary hypertension.