Expression and Clinical Implications of β-tropomyosin in Myocardial Tissues Across Cardiomyopathies

Background β-tropomyosin (TPM2) is a key structural protein that regulates muscle contraction, and its abnormal expression is closely associated with the development of various diseases. However, the expression patterns of TPM2 in different types of cardiomyopathies remain unclear. Objective To investigate the expression patterns and clinical relevance of TPM2 in myocardial tissues from patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and coronary artery disease (CAD). Methods Myocardial tissue samples were collected from patients who underwent heart transplantation or septal myectomy at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology between January 2016 and June 2021, including HCM (septal tissues, n=13), DCM (left ventricular tissues, n=48), and CAD (peri-infarct and non-infarct regions of the left ventricular, n=8). Eight donor hearts (left ventricular tissues, n=8, and septal tissues, n=6) were included as controls. A tissue microarray containing 77 samples was constructed. TPM2 protein expression was assessed by immunohistochemistry and its clinical relevance was analyzed. Results Compared to the donor group, TPM2 expression was significantly reduced in the septal tissue of HCM patients (P