Objective: To observe the possible correlation between expression of chromogranin A (CGA) and myocardial fibrosis and investigate the potential role of CGA in the development of myocardial fibrosis in patients with dilated cardiomyopathy (DCM).
Methods: Surgical myocardial specimen from 10 DCM patients underwent successful orthotopic cardiac transplantation, and 3 normal myocardial specimen from brain-dead organ donors were obtained. CGA-mRNA, COLI-mRNA, COLIII-mRNA and ADAMTS-1-mRNA were analyzed by real-time PCR. The location and expression of CGA were assessed by immunohistochemistry(INH)with anti-CGA antibody. The collagen specific picrosirius red staining was applied on transversal myocardial slides and the collagen volume fraction (CVF) was calculated. The correlation between CGA and CVF was analyzed.
Results: Cytoplasmic expression of CGA assessed by INH showed large amount of strong positive granules densely arranged in the epicardial and endocardial myocardiocytes in DCM specimen while there was only few sparse granules in the normal myocardium (P < 0.05). CVF was significantly higher in DCM myocardial specimen than that in normal specimen (P < 0.001). CGA-mRNA was significantly correlated with COLI-mRNA (r = 0.729), COLIII-mRNA (r = 0.95) and ADAMTS-1-mRNA (r = 0.665, all P < 0.05). Moreover, collagen deposition location was almost identical with the strong positive expression location of CGA.
Conclusion: We demonstrated for the first time that the deposition of CGA was related with the myocardial fibrosis in DCM heart, therefore, CGA might play an important role by influencing myocardial remodeling and fibrosis in DCM patients.