Leptin protects the pancreas from damage induced by caerulein overstimulation by modulating cytokine production

• Published in: Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2002-01, Vol.2 (2), p.89-99
• Main Authors: Jaworek, Jolanta, Bonior, Joanna, Pierzchalski, Piotr, Tomaszewska, Romana, Stachura, Jerzy, Sendur, Ryszard, Leja, Anna, Jachimczak, Bozena, Konturek, Peter C., Bielański, Władystaw, Pawlik, Wiesław, Konturek, Stansław J.
• Format: Article
• Language: English
• Subjects: Animals; Caerulein-induced pancreatitis; Ceruletide - pharmacology; Cytokines - biosynthesis; Gene Expression - drug effects; In Vitro Techniques; Injections, Intraperitoneal; Injections, Intraventricular; Interleukin-4; Interleukin-4 - blood; Leptin; Leptin - administration & dosage; Leptin - genetics; Leptin - metabolism; Leptin - pharmacology; Male; ob gene expression; Original Paper; Osmolar Concentration; Pancreas - drug effects; Pancreas - pathology; Pancreatic acini; Pancreatic blood flow; Pancreatitis - chemically induced; Pancreatitis - pathology; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α
• ISSN: 1424-3903; 1424-3911
• DOI: 10.1159/000055897

Background: Recent identification of specific leptin receptors in the pancreas suggests that this peptide may also play some role in this gland. Aim: To examine the effect of intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) administration of leptin in rats on caeruleininduced pancreatitis (CIP), pancreatic gene expression of leptin and inflammatory cytokine production. Methods: caerulein (25 μg/kg) was infused subcutaneously into conscious rats over 5h to produce CIP. Leptin (1, 5, or 10 μg/kg) was injected i.p. or i.c.v. 30 min prior to the CIP induction. The plasma level of TNFα and IL-4 was determined by ELISA, while plasma leptin was measured by RIA and leptin gene expression in pancreas by RT-PCR. Results: CIP was characterized by the usual pancreatic edema, reduction in pancreatic blood flow (PBF) and an increase in serum levels of amylase, TNFα and IL-4. Pretreatment with i.p. or i.c.v. leptin of the CIP rats partially reversed the harmful effects of CIP on the pancreas, and reduced pancreatic inflammation and the fall in PBF. This was accompanied by a dose-dependent reduction in serum levels of amylase and TNFα, while serum IL-4 in the CIP rats pretreated with leptin rose dose-dependently as compared to control rats with CIP alone. Pretreatment with leptin resulted in the dose-dependent rise in plasma leptin level over that observed in vehicle-treated controls. Leptin mRNA expression in the pancreas was dose-dependently increased after infusion of caerulein. Leptin content in isolated pancreatic acini was also increased dose-dependently by caerulein added to the incubation medium bathing these acini. Conclusions:(1) Exogenous leptin protects the pancreas against damage by CIP; (2) endogenous leptin seems to limit the extend of pancreatic damage, and (3) these protective effects of leptin could be attributed to the reduction in TNFα and to the increase in IL-4 production.