Background. Crohn’s disease (CD) is a chronic intestinal inflammatory disease. An ideal laboratory marker that can predict the prognosis in terms of relapse of the disease is clinically desirable. Methods. A total of 59 CD patients were enrolled in this study. Enzyme-Linked Immunosorbent Assay (ELISA) was used to quantitatively detect the content of D-lactate (D-LA) and the diamine oxidase (DAO) levels in sera obtained from patients and 28 healthy controls. The correlation between these two biomarkers and disease activity scores was assessed. In addition, the ROC curve was used to evaluate the diagnostic accuracy of these two biomarkers. Results. The levels of D-LA in the serum of CD patients in the active stage and remission stage were 16.08±4.8 mg/L and 11.16±3.17 mg/L, respectively, and the difference was statistically significant (t=4.67, P<0.001). DAO levels were significantly higher in patients with the active stage compared to controls. The levels of D-LA and DAO in CD patients were positively correlated with the disease activity (r=0.68 and 0.53, respectively, P<0.05). The area under the ROC curve (AUC) when CD activity was diagnosed with D-LA and DAO alone was 0.815 and 0.748, respectively. The diagnostic efficacy of the two biomarkers was not significantly different from that of the erythrocyte sedimentation (ESR) and hypersensitive C-reactive protein (CRP) (P>0.05). However, the area under the curve was 0.861 (0.746, 0.937) when the diagnosis was performed using a combination of D-LA, DAO, CRP, and ESR, which was significantly higher than when CRP or ESR were tested alone (P<0.05). Conclusions. D-LA and DAO have a good prognostic value for CD activity. Rational combined use of biomarkers can significantly improve the diagnostic efficiency.

Prognostic value of circulating vitamin D binding protein, total, free and bioavailable 25-hydroxy vitamin D in patients with colorectal cancer Prognostic value of circulating vitamin D binding protein, total, free and bioavailable 25-hydroxy vitamin D in patients with colorectal cancer

Ulcerative colitis (UC) is a chronic inflammatory condition of the colon, closely linked to dysbiosis of gut microbiota and imbalances in bile acids. Lithocholic acid (LCA), a secondary bile acid, plays a crucial role in maintaining gut health; however, its specific therapeutic potential in UC remains to be fully elucidated. This study investigates the efficacy of LCA in alleviating UC and explores the underlying mechanisms, particularly focusing on the PXR/TLR4/NF-κB/NLRP3 signaling pathway and gut microbiota modulation. Using a dextran sulfate sodium (DSS)-induced colitis model, our findings demonstrate that LCA administration significantly alleviates colitis symptoms, evidenced by reduced disease activity index (DAI), increased colon length, improved intestinal barrier function, and decreased colonic inflammation. Mechanistically, LCA activates the pregnane X receptor (PXR), which inhibits TLR4-mediated NF-κB/NLRP3 inflammasome activation, leading to reduced colonic inflammation and lower levels of pro-inflammatory cytokines. Furthermore, LCA remodels gut microbiota by promoting beneficial bacterial growth, such as Akkermansiaceae, Lactobacillaceae and Muribaculaceae, while suppressing pathogenic and opportunistic pathogens, including Enterobacteriaceae and Bacteroidaceae. The gut microbiota-dependent effects of LCA were corroborated through antibiotic treatment and fecal microbiota transplantation (FMT) experiments. Notably, the absence of intestinal flora affected PXR expression and activity, modifying the aforementioned effects. Overall, our findings reveal that LCA ameliorates experimental colitis by regulating the PXR/TLR4/NF-κB/NLRP3 signaling cascade and modulating gut microbiota composition. This study underscores LCA’s potential as a targeted therapeutic strategy and a promising microbiota-focused approach for managing UC, offering new insights into the role of bile acids in intestinal health and disease management. Graphical abstract