AIM: To assess the impact of Arpin protein and tight junction(TJ) proteins in the intestinal mucosa onbacterial translocation in patients with severe acute pancreatitis(SAP).METHODS: Fifty SAP patients were identified as study objects and then classified into two groups according to the presence of bacterial translocation(BT) in the blood [i.e., BT(+) and BT(-)].Twenty healthy individuals were included in the control group.BT was analyzed by polymerase chain reaction, colonic mucosal tissue was obtained by endoscopy and the expression of TJ proteins and Arpin protein was determined using immunofluorescence and western blotting.RESULTS: Bacterial DNA was detected in the peripheral blood of 62.0% of patients(31/50) with SAP.The expression of TJ proteins in SAP patients was lower than that in healthy controls.In contrast, Arpin protein expression in SAP patients was higher than in healthy controls(0.38 ± 0.19 vs 0.28 ± 0.16, P < 0.05).Among SAP patients, those positive for BT showed a higher level of claudin-2 expression(0.64 ± 0.27 vs 0.32 ± 0.21, P < 0.05) and a lower level of occludin(OC)(0.61 ± 0.28 vs 0.73 ± 0.32, P < 0.05) and zonula occludens-1(0.42 ± 0.26 vs 0.58 ± 0.17, P = 0.038) expression in comparison with BT(-) patients.Moreover, the level of Arpin expression in BT(+) patients was higher than in BT(-) patients(0.61 ± 0.28 vs 0.31 ± 0.24, P < 0.05).CONCLUSION: Arpin protein affects the expression of tight junction proteins and may have an impact on BT.These results contribute to a better understanding of the factors involved in bacterial translocation during acute pancreatitis. AIM: To assess the impact of Arpin protein and tight junction (TJ) proteins in the intestinal mucosa onbacterial translocation in patients with severe acute pancreatitis (SAP). METHODS: Fifty SAP patients were identified as study objects and then classified into two groups according to the presence of bacterial translocation (BT) in the blood [ie, BT (+) and BT (-)]. Twenty healthy individuals were included in the control group. BT was analyzed by polymerase chain reaction, colonic mucosal tissue was obtained by endoscopy and the expression of TJ proteins and Arpin protein was determined using immunofluorescence and western blotting .RESULTS: Bacterial DNA was detected in the peripheral blood of 62.0% of patients (31/50) with SAP. The expression of TJ proteins in SAP patients was lower than that in healthy controls. In contrast, Arpin protein expression in SAP patients was higher than in healthy controls (0.38 ± 0.19 vs 0.28 ± 0.16, P <0.05) .Among SAP patients, those positive for BT showed ah igher level of claudin-2 expression (0.64 ± 0.27 vs 0.32 ± 0.21, P <0.05) and a lower level of occludin (OC) (0.61 ± 0.28 vs 0.73 ± 0.32, P <0.05) and zonula occludens-1 The level of Arpin expression in BT (+) patients was higher than BT (-) patients (0.61 ± 0.28 vs 0.31 ± 0.24 , P <0.05). CONCLUSION: Arpin protein affects the expression of tight junction proteins and may have an impact on BT. The results of to contribute to a better understanding of the factors involved in bacterial translocation during acute pancreatitis.