Differential expression of hepatocyte growth factor in patients with systemic sclerosis-associated pulmonary arterial hypertension

Introduction Non-invasive biomarkers are needed to identify pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) patients who may benefit from early intervention. We sought to identify novel cytokines that differentiate patients with incident SSc-PAH from those at high risk for PAH. Methods The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) Registry is a multicenter registry of SSc patients at high risk for PAH (at-risk) or with incident right-heart catheterization-confirmed PAH (definite PAH). Serum from 10 at-risk and 9 definite PAH patients were profiled with Bio-PlexTM bead arrays for 48 cytokines and chemokines. We also evaluated the longitudinal change in cytokine profiles from 3 at-risk patients who subsequently developed definite PAH. Results Clinical features of at-risk versus definite PAH patients were not significantly different except for right-ventricular systolic pressure on echocardiogram (34 ± 7 vs. 45 ± 8 mmHg, p = 0.006), left atrial diameter (2.9 ± 0.5 vs. 3.7 ± 0.4 cm, p = 0.02), 6-minute walk distance (508 ± 115 vs. 393 ± 70 m, p = 0.02), mean pulmonary artery pressure (18 ± 4 vs. 32 ± 6 mmHg, p = 0.01), and pulmonary vascular resistance (111 ± 48 vs. 272 ± 109 dyn/s/cm5, p = 0.009). Serum cytokine profiling identified hepatocyte growth factor (HGF) as the only cytokine significantly different between the at-risk and definite PAH groups (225.8 ± 55.0 vs. 361.6 ± 164.5 pg/mL, q<0.1%). Profiling of longitudinal samples of at-risk to definite PAH patients did not identify any significant changes in HGF or other cytokines over time. Conclusions Definite PAH patients expressed higher levels of HGF than at-risk patients. Further studies are needed to clarify the utility of HGF as a predictive biomarker for SSc-PAH.