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DOI: 10.1160/TH05-06-0405
The effect of tissue type-plasminogen activator deletion and associated fibrin(ogen) deposition on macrophage localization in peritoneal inflammation
Financial support: This work was supported by a grant and a Senior Principal Research Fellowship (J.A.H.) from the National Health and Medical Research Council of Australia.Publication History
Received
10 June 2005
Accepted after resubmission
02 February 2006
Publication Date:
30 November 2017 (online)


Summary
There are two plasminogen activators (PAs), urokinase type-PA (u-PA) and tissue type-PA (t-PA). While u-PA is considered to be involved in cellular migration and tissue remodeling and t-PA in fibrinolysis, this distinction is not always clear-cut. With the use of u-PA and t-PA gene deficient mice (u-PA-/and t-PA-/mice, respectively) we have assessed the role of each PA in acute peritonitis. The cellular infiltrate in both thioglycolateand antigen-induced peritoneal exudates was unaffected in u-PA-/mice; in contrast, in t-PA-/mice, the macrophage numbers, particularly of the Mac-1hi population, in the peritoneal cavity by day4 were significantly reduced compared to wild-type mice. However, examination of the peritoneal wall revealed in fact increased numbers of macrophages adhering on/in the cavity lining at all time points studied; in addition, increased fibrin(ogen) staining was observed for these mice. The reduced macrophage numbers in the peritoneal cavities of t-PA-/mice could be increased by administration of plasmin or t-PA prior to harvesting the thioglycolate-elicited exudates. These results suggest that t-PA and not u-PA is the PA controlling fibrinolysis in murine peritonitis. In its absence macrophages adhere to the accumulated fibrin(ogen) on/in the cavity wall lining, most likely via Mac-1 binding, thus affecting migration into and/or out of the peritoneal cavity. They also highlight the need to examine both the peritoneal cavity and wall in order to monitor accurately the extent of a peritoneal inflammatory reaction. Peritoneal inflammation in t-PA-/mice represents a useful model to study the progression of intra-abdominal adhesions during surgery and clinical peritonitis.
Keywords
Tissue type-plasminogen activator - fibrin(olysis) - peritonitis - macrophages - urokinase-type plasminogen activator* These co-authors contributed equally.