Introduction: Idiopathic Pulmonary arteriole hypertension (IPAH) is a rare but severely debilitating disease that strikes women to men at a ratio of 3:1. Endothelial cell (EC) dysfunction is a hallmark of the disease. This includes rapid growth of the ECs until the occlusion of the vasculature as well as decreased blood levels of vasodilators. Markedly increased levels of endothelin-1, a potent vasoconstrictor and smooth muscle mitogen, have been noted in IPAH patients. / Recently mutations in the bone morphogenic protein receptor type II (BMPRII) have been linked to the disease. Interestingly mutations in activin-like kinase-1 (ALK-1) and endoglin have been linked to hereditary haemorrhagic telangiectasia (HHT), a disease that results in PAH clinically indistinguishable from IPAH. All of these proteins are either receptors or co-receptors to members of the TGFbeta superfamily. The connection of these mutations to the disease still remains largely a mystery to researchers and the effects of either bone morphogenic proteins 2, 4, 7 or TGFbeta levels on endothelin-1(ET-1) production in human microvascular endothelial cells cultured from normal lungs (HMVEC-LBI) are unknown. / Methods: HMVEC-LBI cells were cultured in the presence of various concentrations of BMP 2,4,7 and TGFbeta, in complete media or serum starved conditions. After allotted time points the media was collected and assayed by ELISA, meanwhile the cells were lysed and protein content assayed for normalization purposes. Small Mothers against Decapentaplegic (SMAD) 1/5 phosphorylation was also measured. / Results and Conclusions: Despite evidence that all BMPs used were biologically active, namely through SMAD phosphorylation studies, only BMP7 at very high dosages increased ET-1 production levels. TGFbeta had a more pronounced effect at earlier time points with lower concentrations. The results provide insights on the effects of an important group of proteins, the BMPs and TGFbeta, on lung microvascular ECs and which are likely the key cellular player In IPAH development. These findings may have clinical relevance in terms of control of the disease and understanding the normal response of these cells BMPs and TGFbeta.

No description available.