Adropin, S100A1, and SERCA2b Dysregulation in Coronary Artery Disease: Molecular and In Silico Insights into Calcium Signaling and Metabolic Dysfunction.

Background/Objectives: Coronary artery disease (CAD) is a leading cause of cardiovascular morbidity and mortality worldwide. Type 2 diabetes mellitus (T2DM) further increases CAD risk through metabolic disturbances and endothelial dysfunction. Adropin, S100A1, and SERCA2b are important regulators of endothelial function, energy metabolism, and calcium homeostasis. This study aimed to investigate the gene and protein expression levels of these biomarkers in CAD patients with and without T2DM. Methods: Gene and protein expression levels of adropin (ENHO), S100A1, and SERCA2b were evaluated in peripheral blood samples obtained from healthy controls (n = 50), CAD patients (n = 46), and CAD patients with T2DM (CAD+T2DM) (n = 40). Gene expression was determined using real-time PCR, while protein levels were measured with ELISA. Additionally, in silico bioinformatics analyses, such as protein-protein interaction networks and pathway enrichment analyses, were performed to explore potential molecular relationships among these biomarkers. Results: Adropin and ENHO gene expression levels were significantly lower in CAD patients and inversely related to the SYNTAX score. S100A1 levels were also reduced, and SERCA2b gene expression was significantly decreased, especially in the CAD+T2DM group. Bioinformatics analyses revealed that these molecules participate in interconnected pathways related to calcium signaling, cardiac muscle contraction, and metabolic regulation. Conclusions: These findings demonstrate links between altered levels of adropin, S100A1, and SERCA2b and CAD with or without T2DM. However, these observations are preliminary and need validation in larger prospective studies and mechanistic research before drawing definitive conclusions about their clinical utility, disease progression, or prognostic value.