Po-02-175 human epicardial adipocyte-derived sparcl1 plays an important role in suppression of postoperative atrial fibrillation in patients undergoing cardiovascular surgery

Postoperative atrial fibrillation (POAF) occurs in 20-50% after cardiac surgery and exacerbates the short and long-term morbidity/mortality. Potential predisposing factors may exist in the epicardial adipose tissue (EAT) because of its anatomical position. In order to explore a possible mechanistic link, we tried to identify the specific gene expression profile of secretome from the EAT in patients with POAF. We prospectively evaluated 104 patients who underwent scheduled open-heart surgery between May 2020 and May 2022 without known AF (male 69 (66.3%); mean age 68.1 ± 12.3). They are allocated to two groups with (POAF group) or without (no-POAF group) POAF, which is defined as AF lasting over 30 seconds documented by monitor or 12-lead electrocardiogram after the operation. Human EAT samples were obtained from those patients during surgery and preadipocytes were isolated from them. Isolated preadipocytes were terminally differentiated to mature adipocytes and the mRNAs were extracted. Genome-wide expression profiling of 6 vs. 6 matched samples representing POAF or no-POAF group was done using Human Clariom S Assay-HT 16-Array Plate. The secreted protein levels in the adipocytes-cultured medium were also evaluated using enzyme-linked sorbent assay test to confirm the consistency of mRNA expression levels of adipocytes and its secreted protein levels. POAF was observed in 41 patients (39%). Patients in POAF group were significantly older than those in no-POAF group (71.3 ± 9.91 vs 66.0 ± 13.4, p = 0.039). Microarray analysis revealed that there were 132 down- or up-regulated genes (fold change >2.0 or `−2.0, p < 0.05) in epicardial adipocytes of no-POAF group compared to POAF group. Of these genes, 11 genes cording secretable molecules were validated by qPCR, showing that only SPARCL1 had significantly higher expression in no-POAF group than in POAF group (p = 0.039). The mRNA expression of SPARCL1 in adipocytes is significantly correlated with the concentration of SPARCL1 protein in the adipocyte-cultured medium (p < 0.0001, r = 0.9068). Patients aged >75 years had lower mRNA expression of SPARCL1 than patients aged ≤75 years (p = 0.02). Our findings suggested that SPARCL1 expression in human epicardial adipocytes may play an important role in the suppression of POAF in patients undergoing cardiovascular surgery. The expression levels of SPARCL1 are potentially associated with aging.