Newly discovered immune cell type blocks inflammatory heart damage
Rostock – German researchers have identified a new immune cell that mediates protection against inflammatory heart damage (J. Immunol.2010;185:6286-6293). The discovery of the so-called CD8 and Angiotensin receptor 2-positive (AT2R+) T cells open up new avenues for future treatments of patients with inflammatory organ damage such as acute heart attack. Seven days after induction of myocardiac infarction in rats, the group headed by Dr. Jun Lee measured increased levels of the T cells in hearts and spleen compared to sham-operated rats. The T cells secreted cardioprotective IL-10 following AT2R-mediated stimulation. In vivo treatment of rats with an AT2R agonist was found to increase the numbers of IL-10–expressing CD8+AT2R+ T cells in the infarcted myocardium relative to untreated rats. Furthermore, the transplantation of post-infarct splenic CD8+AT2R+ T cells into rats immediately following MI significantly reduced the infarct size, compared with rats that received CD8+AT2R- T cells. As CD8+AT2R+ T cells were also found in healthy human donors, these results have important implications for AT2R-based clinical treatments of acute MI.