Characterization of Duodenal Microbiota in Patients with Acute Pancreatitis and Healthy Controls

OBJECTIVE: The small intestinal bacterial overgrowth (SIBO) in acute pancreatitis correlates with the severity of the disease. However, corresponding studies on the microbial composition of the duodenal mucosa of patients are uncommon. METHODS: Duodenal mucosal biopsies were collected by gastroscopy from 16 patients with mild acute pancreatitis (the Ap group) and 16 healthy individuals (the control group) and subjected to histological studies as well as bacterial 16S rRNA gene sequencing. Caerulein and l-arginine were used to induce mild acute pancreatitis (MAP) and severe acute pancreatitis (SAP) in mice, respectively, and their pancreas and duodenum were collected for histological studies. RESULTS: H&E analysis displayed no significant pathological damage in the descending duodenum of patients with acute pancreatitis compared with that of the controls. Immunofluorescence and Real-time PCR revealed that the expressions of tight junction proteins (TJPs) in duodenal mucosa were decreased in acute pancreatitis. The results of the alpha diversity analysis revealed no significant difference between the two groups, while LEfSe and the random forest revealed a few differences, indicating that the descending duodenum mucosal microbiota changed slightly in patients with mild acute pancreatitis. We observed the pathological changes and the expression of TJPs in the duodenum in the three groups of mice and found that SAP mice had more severe pathological damage in the duodenum. Furthermore, the expression of TJPs in the duodenum was lower in the MAP and SAP groups of mice compared to control mice, but it was similar in both groups. CONCLUSION: Patients with mild acute pancreatitis had mild duodenal barrier dysfunction and slight changes in duodenal mucosal microbiota. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10620-023-07948-8.