Ghrelin is a novel growth hormone-releasing peptide isolated from the stomach and possesses various cardioprotective effects, including energy balance improvement and regulation of autonomic nervous system activity. We investigated the changes in serum ghrelin levels and its association with cardiac function and myocardial infarct size in patients with acute myocardial infarction (AMI). Forty-seven consecutive patients were divided into the following 4 groups: 16 patients with AMI, 12 patients with unstable angina pectoris (UAP), 13 patients with stable angina pectoris (SAP), and 6 control patients. Serum levels were measured with the ELISA kit. Compared to the control (72 ± 26 fmol/mL), SAP (69 ± 47 fmol/mL), and UAP (72 ± 31 fmol/mL) groups, serum ghrelin levels on admission were significantly lower in the AMI group (27 ± 12 fmol/mL, P < 0.01). After admission, the serum ghrelin level gradually increased (30 ± 15 fmol/mL on day 2 and 39 ± 18 fmol/mL on day 7) and became significantly higher on day 14 (49 ± 28 fmol/mL, P < 0.01), compared to the level on admission. In patients with AMI, the ratio of day 14 to admission serum ghrelin levels, an index of AMI-related acute changes in ghrelin, correlated positively with peak creatine phosphokinase levels (R = 0.72, P < 0.01) and the double products (R = 0.60, P < 0.01) and inversely with left ventricular ejection fraction (R = -0.53, P < 0.05). In conclusion, serum ghrelin levels are significantly decreased in association with myocardial infarct size and cardiac function.
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