Diminished macrophage apoptosis and reactive oxygen species generation after phorbol ester stimulation in Crohn's Disease

Abstract

Background: Crohn's Disease (CD) is a chronic relapsing disorder characterized by granulomatous inflammation of the gastrointestinal tract: Although its pathogenesis is complex, we have recently shown that CD patients have a systemic defect in macrophage function, which results in the defective clearance of bacteria from inflammatory sites. Methodology/Principal Findings: Here we have identified a number of additional macrophage defects in CD following diacylglycerol (DAG) homolog phorbol-12-myristate-13-acetate (PMA) activation. We provide evidence for decreased DNA fragmentation, reduced mitochondrial membrane depolarization; impaired reactive oxygen species production, diminished cytochrome c release and increased IL-6 production compared to healthy subjects after PMA exposure. The observed macrophage defects in CD were stimulus-specific, as normal responses were observed following p53 activation and endoplasmic reticulum stress. Conclusion: These findings add to a growing body of evidence highlighting disordered macrophage function in CD and, given their pivotal role in orchestrating inflammatory responses, defective apoptosis could potentially contribute to the pathogenesis of CD. © 2009 Palmer et al.