Detection And Significance Of Key Factors Of TLR4Signaling Pathway In Pancreas And Blood Of Patients With Chronic Pancreatitis

Purpose: Bacterial endotoxin/lipopolysaccharide (LPS) is a trigger factorin the initiation and progression of alcoholic pancreatitis. The stimulation ofTLR4by LPS induces the synthesis and release of critical proinflammatorycytokines that may be related with the development and progression of multipleorgan injury during acute pancreatitis. The aims of this study were to determinethe key cytokines and expression characteristics of genes of TLR4signalingpathway in human chronic pancreatitis in histology and blood.Methods: Pancreatic tissues from24patients with CP and6controls withnormal pancreatic histology were examined for TLR4mRNA by in situhybridization. MyD-88and TNF-α were detected by immunohistochemistry.Computer image analysis was performed to measure the integrated optimaldensity (IOD) of TLR4mRNA, MyD-88and TNF-α positive cells in pancreastissues respectively. Desmin, α-SMA and FSP-1were measured foridentification of pancreatic stellate cells (PSC) in serial sections of pancreatictissues. Meanwhile, both blood plasma and serum from30normal adults and84 patients with CP who had admitted to the first hospital of Jilin University within2days after paroxysm between October of2009and March of2012. sTLR4,TNF-ɑ, IL-1, IL-6and IL-12concentrations in serum of these patients andcontrols were detected by ELISA, while LPS concentrations of plasma weremeasured by spectrophotometry.Results: In situ hybridization analysis showed that a significant increase ofTLR4mRNA could be detected in most perilobular and periacinar PSC, acinarcells and macrophages, but in fewer centroacinar cells, intercalated ducts andintrolobular duct epithelial cells in these patients. Concomitant expressions ofTLR4mRNA, MyD-88and TNF-α proteins were seen in these areas. Computerimage analysis showed that the enhanced expressions of TLR4mRNA, MyD-88and TNF-α proteins were4.2-,6.1-and10.2-fold in these patients comparedwith the normal controls. We analyzed the data with SPSS16.0statisticalsoftware, and found that plasma LPS and serum TNF-ɑ, IL-6, IL-12concentrations of CP patients were significantly higher than that of normalcontrol (P<0.01，P<0.01，P<0.01，P<0.05), furthermore the concentrations ofplasma LPS and serum TNF-ɑ, IL-6, IL-12were positively correlated in CPpatients with endotoxemia.Conclusion: The critical genes of TLR4signaling pathway areover-expressed in CP histology, especially in the PSC, acinar cells andmacrophages. The TLR4and its ligand LPS as well as their response geneproducts in serum were significantly increased. These data indicate that MyD-88-dependent pathway of TLR4signaling may play a role in thepathogenesis of CP.