The Efficacy of Connexin 43 Expression in the Myocardium as an Early Ischemic Marker in Forensic Autopsy

Abstract

The postmortem diagnosis of ischemic heart disease is sometimes difficult for forensicpathologists especially when microscopic ischemic change in the myocardium is notdetected at the early stages of ischemic injury by conventional staining techniques. Connexin 43 (Cx43) is a gap junction protein in human myocardium, which is phosphorylatedand localized to the intercalated discs in the normal cardiac muscles. However, during ischemia and hypoxia, total Cx43 (tCx43) undergoes progressivedephosphorylation and concomitant accumulation of non-phosphorylated Cx43(npCx43) at the lateral cell borders. This study was aimed to evaluate the efficacy ofthe immunohistochemical expression of Cx43 in the myocardium as an early ischemicmarker in forensic autopsy. The study group consisted of 24 cases listing patients whodied of ischemic heart disease (IHD) with severe coronary atherosclerosis thatshowed no myocardial pathology. Cases of sudden death of individuals from non-IHD(n=16) were used as controls. The survival times in both IHD and non-IHD groupswere within 24 hours of the onset of angina symptoms, related injury, or the event forthe cause of death. There was a statistically significant difference in tCx43 andnpCX43 immunopositivity in the IHD group due to their expression patterns. In theIHD group, the redistribution of Cx43 expression from the intercalated discs to the lateralcell borders occurred more frequently than in the non-IHD group. In conclusion,the different expression patterns of tCx43 and npCx43 in the myocardium in IHDcould be used as adjunctive ischemic markers.