Causal Relationship between Gut Microbiota and Acute Pancreatitis Based on the Analysis of Mendelian Randomization

To investigate the correlation between gut microbiota (GM) and acute pancreatitis (AP) using Mendelian randomization technique. The genome wide association study (GWAS) data of GM and AP were selected from the GWAS database, and the inverse variance weighted (IVW), MR-Egger, and weighted median estimator (WME) methods were used. WME for two-sample Mendelian randomization analysis, and tested for heterogeneity, horizontal pleiotropy, and stability of results by sensitivity analysis. IVW results showed that the species of class. Erysipelotrichia (OR = 0.676, 95% CI 0.5328–0.8577, P = 0.0012), class Methanobacteria (OR = 0.867, 95% CI 0.7702–0.976, P = 0.0181), family Rikenellaceae (OR = 0.8223, 95% CI 0.684–0.9887, P = 0.0375), genus. Fusicatenibacter (OR = 0.7922, 95% CI 0.6495–0.9662, P = 0.0215), genus Holdemania (OR = 0.8116, 95% CI 0.7068–0.9319, P = 0.003), genus Terrisporobacter (OR = 0.7557, 95% CI 0.6143–0.9296, P = 0.008), family Methanobacteriaceae (OR = 0.867, 95% CI 0.7702–0.976, P = 0.0181), order Erysipelotrichales (OR = 0.676, 95% CI 0.5328–0.8577, P = 0.0012), order Methanobacteriales (OR = 0.867, 95% CI 0.7702–0.976, P = 0.0181), and family Erysipelotrichaceae (OR = 0.676, 95% CI 0.5328–0.8577, P = 0.0012) may be protective factors for the occurrence of AP, whereas class Mollicutes (OR = 1.2153, 95% CI 1.005–1.4696, P = 0.0441), genus Eubacteriumrectale group (OR = 1.3607, 95% CI 1.0279–1.8012, P = 0.0313), and phylum Tenericutes (OR = 1.2153, 95% CI 1.005–1.4696, P = 0.0441) may be risk factors for AP development. This study explored the causal relationship between intestinal flora and AP and screened the intestinal flora associated with AP, class Mollicutes, genus Eubacterium rectale group and phylum. Tenericutes were associated with an increased risk of AP, whereas class Erysipelotrichia, class Methanobacteria, family Rikenellaceae, genus Fusicatenibacter, genus Holdemania, genus Terrisporobacter, family Methanobacteriaceae, order Erysipelotrichales, order Methanobacteriales, and family Erysipelotrichaceae reduced the risk of developing AP. Our study supports a potential causal relationship between several gut microbiota and AP. Further studies are needed to investigate how gut flora affects the development of AP.