Increased bone morphogenetic protein 10 in precapillary pulmonary hypertension patients

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Netherlands Organization for Scientific Research: NWO-VICI num. 918.16.610 and NWO-VIDI num. 917.18.338. Dutch Heart Foundation Dekker senior post-doc grant num. 2018T059 and the Netherlands CardioVascular Research Initiative: CVON-2017-10 DOLPHIN-GENESIS and CVON-2018-29 PHAEDRA-IMPACT. Fundació La Marató de TV3 num.202038. The Spanish Ministry of Science through the Ramón y Cajal grant num.RYC2021-030866-I. Introduction Precapillary pulmonary hypertension (PH) results in increased right atrial (RA) stretch and pressure. The right atrium is the major source of bone morphogenetic protein (BMP) 10 (BMP10) in adults, mostly produced by RA cardiomyocytes. The major predisposing risk factor for PH involves loss-of-function mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene, through which BMP10 and BMP9 transduce signals. Purpose The aim of this study was to investigate if BMP10 expression is altered in PH, and whether BMP10 signaling activity associates with right ventricular (RV) adaptation, RA function and disease progression. Methods We investigated BMP10 gene and protein expressions in RA tissue. We determined BMP10 and BMP9 plasma levels by ELISA. We studied BMP10 signaling activity in PH and CTEPH patients before and after pulmonary endarterectomy (PEA). Results BMP10 mRNA, protein and activity were significantly increased in the PH right atrium. While circulating levels of BMP10 and BMP9 proteins were increased, no significant changes were observed in BMP10 signaling activity between PH and controls. In a cohort of CTEPH patients, BMP10 signaling activity was reduced after PEA which coincided with improved hemodynamics and RV function. Interestingly, high BMP10 activity was associated with reduced RV function and adaptation, increased RA dilation and decreased RA function. No associations were observed with hemodynamics or general disease markers. Conclusions RA BMP10 expression and plasma levels are increased in precapillary PH. High BMP10 transcriptional activity was associated with worse RV function, RV adaptation, RA dilation and RA function. Future studies are needed to further understand the mechanism underlying BMP10 secretion and function in PH.