Apelin: A Potential Biomarker for Early Diagnosis of Coronary Artery Disease in COPD Patients

Abstract: Background: Apelins, adipokines with anti-inflammatory, vasodilatory, andantiatherosclerotic properties, are implicated in various chronic diseases, includingchronic obstructive pulmonary disease (COPD) and coronary artery disease (CAD).This study investigates the potential of apelin as a biomarker for the early detectionand management of CAD in COPD patients. Methods: A total of 73 stable COPD patients and 35 healthy controls matched for ageand gender were included. COPD patients were divided into two groups: those withoutCAD (Group 1) and those with CAD (Group 2). Serum levels of apelin isoforms (12,13, 17, and 36) were measured using ELISA. Results: Apelin levels were significantly lower in COPD patients compared to controls(p<0.001). Among COPD patients, those with CAD had lower apelin levels than thosewithout CAD (p=0.005 for apelin 12; p<0.001 for apelin 13, 17, and 36). ROC analysisdemonstrated that apelin 13 and 36 had high sensitivity and specificity for predictingCAD in COPD patients. Apelin 13 and 36 were positively correlated with ejectionfraction (EF) (R=0.43, p=0.01; R=0.4, p=0.01), and apelin 12 was correlated with FEV1and FVC (R=0.24, p=0.04; R=0.27, p=0.02). Conclusion: CAD in COPD patients is often underdiagnosed despite its significantimpact on prognosis. Serum apelin levels, particularly apelin 13 and 36, may serve asvaluable biomarkers for the early diagnosis and management of CAD in COPDpatients.Key Words: Apelin, COPD, Coronary Artery Disease, Biomarker, Adipokine