Myocarditis and dilated cardiomyopathy (DCM) are common causes of morbidity and mortality in children and adults. Recently, the human coxsackievirus and adenovirus receptor (CAR), a common receptor for coxsackieviruses and adenoviruses, was discovered and its increased expression has been reported in patients with DCM and myocarditis.
To measure the expression of CAR in myocardial tissues of patients with DCM and its cellular localization in DCM cases.
Formalin-fixed myocardial tissues collected during autopsy from 26 cases of DCM, and 20 cases each of noncardiac disease and cardiac disease other than DCM were included as the test group, and control groups A and B, respectively. Expression of CAR was studied using immunohistochemical staining of myocardial tissue with a CAR-specific rabbit polyclonal antibody. CAR messenger RNA was semiquantified by reverse transcription polymerase chain reaction followed by agarose gel analysis and measurement of band intensity.
CAR positivity in DCM cases was found to be 96% (25 of 26) compared with 30% in control group A and 40% in control group B. CAR was found to be expressed in myocytes, endothelial and interstitial cells; however, positivity in myocytes was significantly higher than in other cells in all groups. The site of CAR expression was predominantly the sarcolemma along with cytoplasm in cardiomyocytes.
The present study highlighted the increased expression of CAR in DCM cases, with localization in myocytes and endothelial cells.