[Pulmonary arterial hypertension in collagenoses: clinical features, epidemiology, pathogenesis, diagnosis and treatment]

Bone morphogenetic protein 9, and its genetic variants contribute to susceptibility of idiopathic pulmonary arterial hypertension

Considering the predominant role of rare variants of the Bone morphogenetic protein 9 (BMP9) gene in the occurrence of idiopathic pulmonary arterial hypertension (IPAH), here we conducted a case-control study, together with functional validation, to explore the relationships between variants of the BMP9 gene and development of IPAH. We found minor alleles of rs3740297 (OR: 0.72, 95% CI: 0.59-0.87, P=7.77×10-5) and rs7923671 (OR: 0.76, 95% CI: 0.62-0.93, P=0.009) were significantly associated with decreased risk of IPAH. Minor alleles of rs3740297 and rs7923671 were significantly associated with increased plasma level of BMP9 in both IPAH cases and controls (P<0.001). An allele of rs7923671 showed higher relative luciferase activity compared to that containing G allele (P<0.001). Mechanism exploration found that pulmonary artery smooth muscle cells (PASMC) cell line transfected with rs3740297 C allele construct, miR-149 mimic, and antagomir miR-149 showed more sensitive change of the relative luciferase activity and BMP9 expression. This means minor allele T of rs3740297 could significantly decrease susceptibility of IPAH in Chinese population, possibly by increasing BMP9 expression through losing a miR-149 binding site. Our study provides evidence for genetic associations between two specific variants in the BMP9 gene and plasma level of BMP9, occurrence of IPAH.

[Pulmonary arterial hypertension in collagenoses]

Pulmonary arterial hypertension is a rare disease of small pulmonary arteries of unknown origin characterised by endothelial dysfunction and cellular proliferation throughout all vessel layers, resulting in progressively elevated pulmonary arterial resistance with increasing right heart strain and finally right heart failure. The condition may develop in connective tissue diseases with variable frequency leading to a substantial worsening of prognosis. However, the spectrum of therapeutic options has broadened significantly in recent years. Several compounds have gained approval that act mainly as pulmonary vasodilators. Further drugs are under investigation, some of which target pulmonary vascular remodeling. Echocardiography remains the primary examination for disease detection. To classify pulmonary hypertension definite hemodynamic evaluation by means of right heart catheterisation and a thorough differential diagnosis are essential to provide the basis for further treatment. For differential therapy and assessment of follow-up profound knowledge is required, pointing to the need for close cooperation with specialised centres.