A Comparative Study on Cardiac Pathology between Sudden Death Due to DCM and DCM Patients
|School||Huazhong University of Science and Technology|
|Keywords||DCM sudden death Heart transplantation Connexin43 Immunohistochemistry Computerized image analysis|
【Background】As one of the most visible kind of cardiomyopathy, Dilated Cardiomyopathy(DCM) is characterized by dilation and impaired contraction of the left or both ventricles. It may be idiopathic, familial/genetic or immune, alcoholic, or associated with cardiovascular diseases being known in which the degree of cardiac dysfunction cannot be explained by the abnormal loading conditions and the extent of ischemic damage. Presentations are arrhythmias, thrombosis and sudden death, which are usually with progressive heart failure and may occur at any stage.DCM is the kind of myocardiovascular disease in which heart failure is usually ensuing and the transplantation of heart is the only healing treatment, but is often ended with sudden death, where the rate is as high as 40%. Numbers of scientists home and abroad have studied a lot about DCM to search its etiology, pathogenesis, brand new diagnosis and treatment methods from different aspects, such as the clinical medicine, the basic medicine and molecular biology, etc. It is true that they got progressive recognition about DCM while the correct etiology, pathogenesis and the mechanism of sudden death are not as clear as possible.Recently, the expression and distribution of myocardial connexin43 in DCM is broadly observed. It is known to all that the Connexin(Cx) expression in the myocardiovascular system is mostly Cx37, Cx40, Cx43, Cx45 and Cx46. It is indicated that Cx43 expresses primarily in ventricular myocardium and its expression and distribution is associated with ischemic, infarct of myocardium and the ventricular arrhythmias. While the sudden death due to DCM is caused by ventricular arrhythmias, it is important to study the relationship between the expression and distribution of Cx43 in ventricular myocardium and the sudden death due to DCM, aiming at providing different visions for further studying the etiology, pathogenesis and the mechanism of sudden death due to DCM.【Objective】To study the expression and distribution of Cx43 in the left and right ventricles in the cases of sudden death from DCM and patients with DCM, and the relationship and difference between those two situations in order to afford a brand new reference for searching the etiology, pathogenesis and mechanism of sudden death and even the diagnosis and treatment of DCM; to offer some special thoughts for forensic diagnosis of sudden death due to DCM.【Materials and methods】13 autopsy cases of sudden death caused by DCM and the heart samples, case materials and paraffin blocks were chosen from the Department of Forensic Science, Tongji Medical College , Huazhong University of Science and Technology from 1997 to 2010 which are defined as group A. Group B is the patients with DCM done heart transplantation. The heart samples were done steeply to make slices. The computerized imaging and immunohistochemistry technology (SABC method) were used to detect the myocardial Cx43 expression and distribution in the ventricles in both groups. The area and optical density (OD) of Cx43 expression in DCM in the ventricles were quantitatively detected by imaging analytic system. All data were conducted with SPSS 12.0 professional statistical software package.【Results】1.General material: In group A, all 13 cases died of DMC include 11 males and 2 females with age ranging from 17 to 49 except two child of 7 and 17 years old while in group B, 5 cases with heart transplantation consist of 3 males and 2 females with age ranging from 44 to 55 except one child of 13 years old. 2. Pathological changes: Both of the left and right ventricles in both groups are extensively dilated. Myocardial connexin43 expression in both of left and right ventricles decreases obviously in group A with dying spots different in size, colour and disparity. In group B, myocardial connexin43 expresses clearly with only slight changes in dying spots. 3. Image quantitative analysis: Remarkable differences in expression areas(S value) between group A and B with P=0.007 while no obvious differences in left and right ventricles in both group A and B; about OD value, no difference in any comparative study in group A and B.【Conclusion】There is no meaningful difference in the appearance and pathological changes of both two groups. Connexin43 expression decreases obviously in cases of sudden death due to DCM comparative to patients with heart transplantation of DCM which may due to the occurrence of sudden death caused by arrhythmias and heart failure . Of course, not enough cases may also contribute to the result.