As cardioprotective and angiogenic biomarker, can ghrelin predict coronary collateral development and severity of coronary atherosclerosis?

OBJECTIVE
Ghrelin exerts protective effects on cardiovascular system by inhibiting progression of atherosclerosis, supression of vascular inflammation, and stimulating angiogenesis. Thus, the aim of this study was to investigate the effect of serum ghrelin on coronary collateral development and SYNTAX score in patients with severe coronary artery disease.

METHODS
Total of 91 patients who had ≥90% stenosis in at least one major coronary artery were prospectively included in this cross-sectional, observational study. Collateral degree was graded according to Rentrop-Cohen classification. Patients with grade 2 or 3 collateral degree were allocated to Good Collateral Group and patients with grade 0 or 1 collateral degree were included in Poor Collateral Group. Ghrelin and vascular endothelial growth factor A (VEGF-A) levels were measured using radioimmunoassay and ELISA kits.

RESULTS
Serum ghrelin and VEGF-A levels were significantly higher in Good Collateral Group. Furthermore, ghrelin level showed significant inverse correlation with SYNTAX score (r=-0.348; p=0.001). In multivariable regression analysis, ghrelin (Odds ratio, 1.013; 95% confidence interval, 1.011–1.017; p=0.013), VEGF-A, fasting plasma glucose and presence of chronic total occlusion were independent predictors of good collateral development. In receiver operating characteristic curve analysis, ghrelin value cut-off point of ≥781 pg/mL predicted good collateral development with sensitivity of 73.1% and specificity of 67.7%.

CONCLUSION
Findings suggested that ghrelin has antioxidant and antiinflammatory properties that protect endothelial functions and also stimulate angiogenesis, which results in development of good coronary collateral and inhibition of progression of coronary atherosclerosis.