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

## TL;DR

This study finds that macrophages attached to injured heart cells in patients with dilated cardiomyopathy correlate with lower levels of a heart injury marker in the blood.

## Contribution

The study introduces macrophages adhered to injured cardiomyocytes as a novel marker for ongoing inflammation in dilated cardiomyopathy.

## Key findings

- 72 out of 181 patients with DCM had macrophages attached to injured cardiomyocytes.
- The number of macrophages adhered to injured cardiomyocytes correlated negatively with serum cardiac troponin T levels.
- Two distinct patterns of macrophage localization were identified in DCM biopsies.

## Abstract

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.

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

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.

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).

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