Postmortem biochemical analysis of soluble ST2 in the pericardial fluid of patients with sudden cardiac death caused by ischemic heart disease: a pilot study

Soluble growth stimulation expressed gene 2 protein (sST2) is a myocardial protein induced by biomechanical stress. sST2 is widely present in the serum of patients with heart failure and is recommended as an important indicator to predict adverse outcomes in these patients. However, no postmortem biochemical analysis of sST2 in forensic practice has been reported. The present pilot study aimed to investigate the expression of sST2 in the pericardial fluid of patients with sudden cardiac death (SCD) caused by ischemic heart disease (IHD). In addition, to explore the relationship of sST2 with CK-MB, cTnT, and NT-proBNP, which have been proven to be auxiliary biomarkers for the diagnosis of SCD, we analyzed CK-MB, cTnT, NT-proBNP, and sST2 levels in twenty-one pericardial fluid samples from the Center of Forensic Investigation, China Medical University, with a Roche cobas e 411 electrochemiluminescence automatic immunoassay system and ST2/IL-33R Valukine™ enzyme-linked immunosorbent assay kit. The levels of sST2 in the pericardial fluid of patients with SCD caused by IHD were significantly increased ( P < 0.01) and positively correlated with CK-MB and NT-proBNP ( P < 0.0001). Receiver operating characteristic curve analysis indicated that the combined measurement of sST2 and NT-proBNP has a higher diagnostic value for SCD caused by IHD than the measurement of either indicator alone. This study preliminarily demonstrated that sST2 in the pericardial fluid was significantly increased in patients with SCD caused by IHD and might be used as a novel auxiliary biomarker for postmortem diagnosis of SCD in forensic practice.