Expression of cell adhesion molecules in dilated cardiomyopathy: evidence for endothelial activation in inflammatory cardiomyopathy.

BACKGROUND

Dilated cardiomyopathy (DCM) is pathogenically linked to inflammatory cardiomyopathy (InfCM), which is characterized by intramyocardial infiltration. The transendothelial migration of immunocompetent cells is mediated by cell adhesion molecules (CAMs).

METHODS AND RESULTS

We investigated the expression pattern of CAMs (immunoglobulin superfamily, 32 selectins, and beta1- and beta2-integrins) in endomyocardial biopsies from DCM patients (n=152; left ventricular ejection fraction <40%) using immunohistochemistry. Whereas few specimens obtained at autopsy (controls; n=14) presented enhanced expression regarding single endothelial CAMs (human leukocyte antigen [HLA] class I, 7%; HLA-DR, 14%; CD29, 14%), none demonstrated concurrent abundance of >3 CAMs (inflammatory endothelial activation), nor did any control tissue prove positive for InfCM (>7.0 CD3+ lymphocytes per 1 mm2). In comparison, 64% (n=97) of the DCM biopsies were evaluated positive for InfCM and 67% (n=101) for inflammatory endothelial activation, respectively. Whereas expression of HLA class I, HLA-DR, intercellular cell adhesion molecule-1, and CD29 was distributed homogeneously within a patient's serial sections, immunoreactivity of vascular cell adhesion molecule-1, lymphocyte function antigen-3, and the selectins was accentuated on single vascular endothelia. Sixty-six percent of the DCM biopsies presented CD29 abundance also within the extracellular matrix and the sarcolemma. CD62P and CD62E were present in 16% and 40% of the DCM patients, respectively. Endothelial CAM representatives correlated with one another (P<0.05), except for CD62P with HLA. Endothelial CAM expression correlated with intramyocardial infiltrates phenotyped by the corresponding counterreceptors.

CONCLUSIONS

Inflammatory endothelial activation is present in 67% of DCM patients. Because CAM expression correlates with the immunohistological diagnosis of InfCM and counterreceptor-bearing intramyocardial infiltrates, evaluation of endothelial CAMs might be of diagnostic significance in InfCM.