Specific Therapy Modulate Circulating Levels of Adiponectin in Patients with Pulmonary Arterial Hypertension

Abstract

Purpose Adiponectin (APN), a protein produced by adipose tissue, is associated with reduced risk for cardiovascular diseases. We hypothesised that circulating levels of APN reflects severity and hemodynamic features of diseases such as pulmonary arterial hypertension (PAH), and that APN reflects effects of specific therapy. Methods and Materials Blood samples were obtained simultaneously from the radial artery (RA) and the pulmonary artery (PA) in patients with PAH (n=14, 7 patients with idiopathic PAH and 7 patients with associated PAH) during right heart catheterization at baseline and with follow-up after the specific treatment. The level of APN was estimated by enzyme-linked immunosorbent assay. Results The patients had a severe pulmonary hypertension with mean pulmonary artery pressure (mPAP) of 50 ± 15 mm Hg (mean±SD) and pulmonary vascular resistance (PVR) of 9.1±4.1 WU. Plasma levels of APN in RA and PA were lower at baseline than at follow up (20.5±14.8μg/ml and 26.7± 16.4μg/ml vs.35.8±27.7 and 30.0±22.5 μg/ml with p=0.08 and p=0.66 respectively), despite no significant changes in hemodynamic parameters. Circulating levels of APN were higher in PA than in RA (p=0.07). Mean plasma APN (RA) levels in men are lower than those found in women (26.5±15.6 vs.9.8±3.1 μg/ml; p=0.04). In this small group we found significant correlation between APN levels, hemodynamic variables, gender and inflammatory cytokines. Conclusions The results from our small study implicated that the levels of APN rose with increasing PH severity grade. Pharmacological treatment has a possibility of modulating circulating levels of APN. This positive relation between APN and PAH severity may reflect an underlying adaptive response that is not attenuated during the specific pharmacological management. Adiponectin correlations Radial Artery Pulmonary Artery Correlations r p-value r p-value RAP 0.80 0.001 0.74 0.003 mPAP 0.87 0.80 0.001 IL-1β 0.75 0.003 0.57 0.04 IL-6 0.63 0.02 0.58 0.037 IL-8 0.81 0.001 0.74 0.004 RAP - right atrial pressure