Anti-inflammatory action of apoptotic cells in patients with acute coronary syndromes

Abstract 

Objectives

Atherosclerotic plaques contain both apoptotic cells and phagocytes. Apoptotic cells are known to exert an anti-inflammatory effect. Little is known on their action in patients with acute coronary syndromes.

Methods and results

We challenged mononuclear phagocytes from the peripheral blood of patients with acute coronary syndromes (n=20) and healthy controls (n=30) with lipopolysaccharide (LPS, 100ng/ml) or peptidoglycan (PGN, 20μg/ml) in the presence or in the absence of apoptotic cells. After 24h, mononuclear phagocytes from patients with acute coronary syndromes produced more TNFα and IL-10 than controls; moreover, they were significantly more susceptible to the anti-inflammatory action of apoptotic cells. Apoptotic cells were more effective in ACS patients with C-reactive protein levels <3mg/l than in patients with CRP levels >3mg/l.

Conclusions

Patients with acute coronary syndromes and low circulating C-reactive protein levels are more sensitive to the anti-inflammatory action of apoptotic cells: this suggests the existence of an enhanced anti-inflammatory feedback circuit, which could contribute to protect from plaque instability.

Keywords: Coronary disease, Apoptosis, Cytokines, Macrophages, Atherosclerosis