Organ specific apoptosis following polymicrobial intraperitoneal infection

Background Leukocyte apoptosis allows safe removal of potentially harmful cells and facilitates resolution of inflammation. We hypothesized that the number of apoptotic cells changes in a disproportionate fashion in parenchymal organs in response to intra-abdominal infection. Materials and methods The percentage of apoptotic cells in the liver, spleen, lung, and peripheral blood was evaluated following cecal ligation and puncture (CLP) in mice. Tissue myeloperoxidase (MPO) levels were measured as an index of neutrophil extravasation. Results Liver & spleen MPO continually increased, while lung MPO remained low after CLP. In parallel to the increase in MPO, liver & spleen apoptosis continually increased throughout the 9-day follow-up period, whereas lung apoptosis remained unchanged. Conclusions The distribution of apoptotic cells during intraperitoneal infection occurs in an organ specific manner, with significant increases in the spleen and liver. This distribution likely reflected the clearance of apoptotic cells as the inflammatory focus became contained. Supported by the American Association for the Surgery of Trauma, John H. Davis Research Scholarship, and by the Veterans Administration Merit Review Project 0005. Received 7 October 2005; returned for revision 22 November 2005; accepted by G. Wallace 23 December 2005