Circulating ghrelin was negatively correlated with pulmonary arterial pressure in atrial septal defect patients

Abstract

Background Ghrelin was found to attenuate the magnitude of pulmonary arterial hypertension and pulmonary vascular remodeling in rats. The objective of this study was to explore the fasting plasma ghrelin level and the relationships between ghrelin and pulmonary arterial pressure (PAP) in atrial septal defect (ASD) patients with pulmonary arterial hypertension (PAH). Methods Fasting plasma ghrelin, obestatin, and insulin levels were measured by enzyme linked immunosorbent assay (ELISA) method in ASD patients with or without PAH according to the manufacturer's instructions. Insulin resistance was calculated by the homeostasis model of assessment for insulin resistance (HOMA-IR) approach, calculated as fasting insulin (microunits/ml)× fasting blood glucose (mmol/L)/22.5. Comparisons between the parameters of patients with PAH and those of patients with normal PAP were performed with an unpaired Student's t test. The relationships between ghrelin and various clinical parameters were examined by bivariate correlations and multiple regression analysis. Results We found that the fasting plasma ghrelin level and the ratio of ghrelin to obestatin were significantly lower in the PAH group compared with the control group ((582.4±12.8) pg/ml vs. (1045.2±95.5) pg/ml, P <0.05 and 30.5±4.9 vs. 70.0±9.7, P <0.01). The fasting plasma obestatin level was higher in the PAH group compared with the control group, but the difference between them was not significant ((23.2±3.1) pg/ml vs. (16.3±1.6) pg/ml, P >0.05). In a multiple regression model analysis, only mean PAP was an independent predictor of ghrelin and the ratio of ghrelin to obestatin (standardized coefficient=-0.737, P <0.001 and standardized coefficient=-0.588, P=0.006, respectively). Conclusion Ghrelin is negatively correlated with mean PAP and this suggests that circulating ghrelin might predict the severity of pulmonary hypertension in ASD patients with PAH.