The specific mechanism of pulmonary arterial hypertension (PAH) remains elusive. The present study aimed to explore the underlying mechanism of PAH through the identity of novel biomarkers for PAH using metabolomics approach. Serum samples from 40 patients with idiopathic PAH (IPAH), 20 patients with congenital heart disease‐associated PAH (CHD‐PAH) and 20 healthy controls were collected and analysed by ultra‐high‐performance liquid chromatography coupled with high‐resolution mass spectrometry (UPLC‐HRMS). Orthogonal partial least square‐discriminate analysis (OPLS‐DA) was applied to screen potential biomarkers. These results were validated in monocrotaline (MCT)‐induced PAH rat model. The OPLS‐DA model was successful in screening distinct metabolite signatures which distinguished IPAH and CHD‐PAH patients from healthy controls, respectively (26 and 15 metabolites). Unbiased analysis from OPLS‐DA identified 31 metabolites from PAH patients which were differentially regulated compared to the healthy controls. Our analysis showed dysregulation of the different metabolic pathways, including lipid metabolism, glucose metabolism, amino acid metabolism and phospholipid metabolism pathways in PAH patients compared to their healthy counterpart. Among these metabolites from dysregulated metabolic pathways, a panel of metabolites from lipid metabolism and fatty acid oxidation (lysophosphatidylcholine, phosphatidylcholine, perillic acid, palmitoleic acid, N‐acetylcholine‐d‐sphingomyelin, oleic acid, palmitic acid and 2‐Octenoylcarnitine metabolites) were found to have a close association with PAH. The results from the analysis of both real‐time quantitative PCR and Western blot showed that expression of LDHA, CD36, FASN, PDK1 GLUT1 and CPT‐1 in right heart/lung were significantly up‐regulated in MCT group than the control group.

No abstract

This study investigated the clinical value of plasma asymmetrical dimethyl-L-arginine (ADMA) level in the diagnosis, staging, and treatment response in congenital heart disease (CHD) patients with pulmonary arterial hypertension (PAH). This was a single-center prospective observational study in 80 CHD patients. Plasma ADMA levels were measured by enzyme-linked immunosorbent assay. Plasma ADMA levels were significantly increased in CHD patients with PAH compared with CHD patients without PAH (P < 0.01) and healthy controls (P < 0.001). In CHD patients with severe PAH, plasma ADMA levels were significantly higher in patients with Eisenmenger's syndrome (ES) than in patients exhibiting low pulmonary vascular resistance (P < 0.001). The plasma ADMA levels significantly correlated with pulmonary arterial pressure (P < 0.001) and pulmonary vascular resistance (P < 0.001) in patients with CHD. Severe PAH was identified by plasma ADMA with a cutoff value of 0.485 μmol/L (P < 0.001) with a specificity of 82.8 % and a sensitivity of 90 %. ES was identified by plasma ADMA with a cutoff value of 0.85 μmol/L (P < 0.05) with a specificity of 85.2 % and a sensitivity of 64.3 %. ADMA levels were significantly decreased after sildenafil therapy for 6 months compared with before therapy levels (0.91 ± 0.22 vs. 0.57 ± 0.30, P < 0.01). Our study suggests that plasma ADMA level may be used as a biomarker for identifying PAH in patients with CHD, assessing pulmonary vascular remodeling, and evaluating the treatment response of CHD patients with PAH to sildenafil.