Adhered macrophages as an additional marker of cardiomyocyte injury in biopsies of patients with dilated cardiomyopathy.

BACKGROUND

Macrophage accumulation found in biopsy specimens of patients with dilated cardiomyopathy (DCM) has been thought to reflect chronic myocarditis. However, it is unsettled whether they are responsible for the active or persistent phase of the disease.

OBJECTIVE

The aim of this study was to count the number of macrophages in relation to plasma concentrations of cardiac troponin T (cTnT).

METHODS

We studied the biopsies of 181 patients with DCM by immunohistochemistry using anti-CD68(+) antibodies. The total number of CD68(+) and the number of CD68(+) cells attached to injured cardiomyocytes were counted and presented as the number of cells/mm2.

RESULTS

Two expression patterns of CD68(+) macrophages were observed: those localized freely in the interstitial space only, and the cells attached to injured cardiomyocytes. As regards macrophages adhered to injured cardiomyocytes, 72 out of 181 (39.8%) patients presented these cells in the biopsy sections. Both the total number of CD68(+) macrophages and the number of CD68(+) cells directly adhered correlated negatively with cTnT in the serum of DCM patients (Spearman's rho, r = -0.45, P < 0.001 and r = -0.31, P = 0.009, respectively).

CONCLUSION

Macrophages attached to injured cardiomyocytes may reflect chronic (ongoing) inflammation in the myocardium.