RESUMO
BACKGROUND: Carbohydrate antigen 125 (CA125) is a proteolytic fragment of MUC-16 that is increased in heart failure (HF) and associated with inflammation, fluid overload, and worse adverse events. Our main objective was to study the expression of CA125 on epicardium and its association with inflammation, adipogenesis, and fibrosis. METHODS: Epicardial fat biopsies and blood were obtained from 151 non-selected patients undergoing open heart surgery. Immunohistochemistry, ELISA, or real-time PCR were used for analyzing protein or mRNA expression levels of CA125 and markers of inflammatory cells, fibroblasts, and adipocytes. Epithelial or stromal cells from epicardium were isolated and cultured to identify CA125 and its association with the adipogenesis and fibrosis pathways, respectively. RESULTS: The median age was 71 (63-74) years, 106 patients (70%) were male, and 62 (41%) had an established diagnosis of HF before surgery. The slice of epicardial fat biopsy determined a positive and colorimetric staining on the epithelial layer after incubating with the CA125 M11 antibody, providing the first description of CA125 expression in the human epicardium. Epicardial CA125 showed a strong and positive correlation with markers of inflammation and fibrosis in the epicardial fat tissue while exhibiting a negative correlation with markers of the adipogenesis pathway. This relationship remained significant after adjusting for potential confounders such as a prior HF diagnosis and plasma CA125 levels. CONCLUSION: Epicardial cells express CA125, which is positively associated with inflammatory and fibroblast markers in epicardial adipose tissue. These results suggest that CA125 may be biologically involved in HF progression (transition from adipogenesis to fibrosis).