Role of platelets in experimental acute pancreatitis.
BACKGROUND
Platelets not only control thrombosis and haemostasis but may also regulate inflammatory processes. Acute pancreatitis (AP) is characterized by changes in both coagulation and proinflammatory activities. The role of platelets in AP is not yet known.


METHODS
AP was induced in C57BL/6 mice by repeated caerulein administration (50 µg/kg intraperitoneally). Mice received a platelet-depleting or control antibody before caerulein challenge. Neutrophil infiltration, myeloperoxidase (MPO) and macrophage inflammatory protein (MIP) 2 levels, acinar cell necrosis and haemorrhage in the pancreas, as well as serum amylase activity, were determined 24 h after caerulein injection. In an alternative model of pancreatitis, L-arginine (4 g/kg intraperitoneally) was given twice with an interval of 1 h and tissue samples were taken after 72 h [Correction added after online publication 29 September 2010: in the preceding sentence, 4 mg/kg was corrected to 4 g/kg].


RESULTS
Caerulein administration increased acinar cell necrosis, neutrophil infiltration, focal haemorrhage and serum amylase levels. Platelet depletion reduced acinar cell necrosis, haemorrhage and serum amylase levels in AP. Depletion of platelets decreased caerulein-induced MPO levels and neutrophil recruitment in the pancreas. Platelet depletion abolished caerulein-induced MIP-2 generation in the pancreas and circulation. The effects of platelet depletion on necrosis, neutrophils and MPO levels were confirmed in L-arginine-induced pancreatitis.


CONCLUSIONS
Platelets play a crucial role in AP by regulating neutrophil infiltration, most likely mediated by MIP-2 production in the pancreas.
Abdulla
A
A
Department of Clinical Sciences, Section for Surgery, Malmö University Hospital, Lund University, S-205 02 Malmö, Sweden.
Awla
D
D
Hartman
H
H
Rahman
M
M
Jeppsson
B
B
Regnér
S
S
Thorlacius
H
H
D000681:Amylases / Q000097:blood; D000818:Animals; D000906:Antibodies / Q000097:blood; D001120:Arginine / Q000009:adverse effects; D001792:Blood Platelets / Q000502:physiology*; D002108:Ceruletide / Q000009:adverse effects; D054426:Chemokine CXCL2 / Q000096:biosynthesis / Q000378:metabolism; D005434:Flow Cytometry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018375:Neutrophil Activation / Q000502:physiology; D010195:Pancreatitis / Q000097:blood* / Q000139:chemically induced / Q000473:pathology; D009195:Peroxidase / Q000378:metabolism; D010974:Platelet Aggregation / Q000502:physiology; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000276:immunology
D000906:Antibodies; D054426:Chemokine CXCL2; D019038:Platelet Glycoprotein GPIb-IX Complex; D002108:Ceruletide; D001120:Arginine; D009195:Peroxidase; D000681:Amylases