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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Antibodies, Monoclonal, Apoptosis, Caspases, Cells, Cultured, Chronic Disease, Crohn Disease, Cytochrome c Group, Enzyme Activation, Fas Ligand Protein, Gastrointestinal Agents, Humans, Infliximab, Lipopolysaccharide Receptors, Membrane Glycoproteins, Membrane Proteins, Monocytes, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-bcl-2, Transcriptional Activation, Tumor Necrosis Factor-alpha, bcl-2 Homologous Antagonist-Killer Protein, bcl-2-Associated X Protein.
user
Does infliximab induce apoptosis in monocytes from patients with chronic active Crohn 's disease by using a caspase-dependent pathway? Context: Treatment with a chimeric anti-tumor necrosis factor (TNF) antibody (infliximab) has been shown to be highly efficient for patients with steroid-refractory Crohn's disease (CD). However, the mechanism of action remains largely unknown. As monocytopenia is commonly observed after treatment with infliximab, we investigated the role of infliximab-induced monocyte apoptosis. Peripheral blood monocytes from healthy volunteers and patients with chronic active CD (CDAI > 250) were isolated by density gradient centrifugation methods. Apoptosis was determined by annexin V staining DNA-laddering, and transmission electron microscopy. Activation of caspases and mitochondrial release of cytochrome C was determined by immunoblotting. Transcriptional activation of members of the Bcl-2 family have been analyzed by ribonuclease protection assay. Treatment with infliximab at therapeutic concentrations resulted in monocyte apoptosis in patients with chronic active CD in a dose-dependent manner. Infliximab-induced monocyte-apoptosis required the activation of members of the caspase-family since activation of caspase-8, -9, and -3 could be determined. Caspase activation was induced by a CD95/CD95L independent signaling pathway with mitochondrial release of cytochrome C. Cytochrome C release seemed to be triggered by transcriptional activation of Bax and Bak. Monocyte apoptosis in vivo as determined by annexin-V binding and caspase-3 activation could be shown in patients with chronic active CD as soon as 4 hours after treatment with infliximab.
assistant
Monocyte apoptosis induced by infliximab may be an important mechanism that could explain the powerful anti-inflammatory properties of infliximab in patients with chronic active CD. Final Decision: yes