Background: Identifying patients at high risk of developing chronic postsurgical pain (CPSP) is of extreme importance in order to help launch appropriate therapeutic strategies and intensive initiation of pain management. Aim: In this study, we aimed to conduct a multi-center retrospective cohort study to establish a prognostic model and a nomogram to predict the risks of CPSP in elderly patients who underwent hip arthroplasty at 6 months postoperatively. Methods: We collected data from 736 patients aged > 65 years who had undergone hip arthroplasty from October 1, 2016 to September, 30, 2018 at multiple tertiary referral centers in Guangzhou, China. All data were randomly stratified into a training set and a testing set at a ratio of 8:2. Data were analyzed via multiple logistic regression analysis with receiver operating characteristic (ROC) curves and areas under the curve. This model was further validated by estimating calibration and discrimination. A nomogram was ultimately developed. Results: A total of 736 eligible patients were enrolled, 27.20% of whom developed CPSP within 6 months postoperatively. Preoperative pain in the surgical area (OR=2.456, 95% CI:1.814– 3.327, P< 0.001), preoperative depression state (OR=1.256, 95% CI:1.146– 1.378, P< 0.001), surgical type (OR=7.138, 95% CI:3.548– 14.364, P< 0.001), acute postoperative numerical rating scale score (OR=5.537, 95% CI:3.607– 8.499, P< 0.001) and analgesic type (patient-controlled epidural analgesia: OR=0.129, 95% CI:0.055– 0.299, P< 0.001; patient-controlled intravenous analgesia: OR=0.033, 95% CI:0.011– 0.097, P< 0.001) were identified as independent significant factors associated with CPSP. A prognostic model was established and further validated. An ROC curve confirmed the predictive ability of this model with a high sensitivity value of 92.12% (95% CI:86.90– 95.74) and specificity value of 91.72% (95% CI:88.77– 94.11). A nomogram was developed to simplify the use of the predictive model in clinical practice. Conclusion: This prognostic model could be of great value in clinical practice, serving as the basis for early personalized analgesic management of elderly patients undergoing hip arthroplasty.

Background: Iron status has been implicated in gastrointestinal diseases and gut microbiota, however, confounding factors may influence these associations.Objective: We performed Mendelian randomization (MR) to investigate the associations of iron status, including blood iron content, visceral iron content, and iron deficiency anemia with the incidence of 24 gastrointestinal diseases and alterations in gut microbiota.Methods: Independent genetic instruments linked with iron status were selected using a genome-wide threshold of p = 5 × 10−6 from corresponding genome-wide association studies. Genetic associations related to gastrointestinal diseases and gut microbiota were derived from the UK Biobank, the FinnGen study, and other consortia.Results: Genetically predicted higher levels of iron and ferritin were associated with a higher risk of liver cancer. Higher levels of transferrin saturation were linked to a decreased risk of celiac disease, but a higher risk of non-alcoholic fatty liver disease (NAFLD) and liver cancer. Higher spleen iron content was linked to a lower risk of pancreatic cancer. Additionally, higher levels of liver iron content were linked to a higher risk of NAFLD and liver cancer. However, certain associations lost their statistical significance upon accounting for the genetically predicted usage of cigarettes and alcohol. Then, higher levels of iron and ferritin were associated with 11 gut microbiota abundance, respectively. In a secondary analysis, higher iron levels were associated with lower diverticular disease risk and higher ferritin levels with increased liver cancer risk. Higher levels of transferrin saturation were proven to increase the risk of NAFLD, alcoholic liver disease, and liver cancer, but decrease the risk of esophageal cancer. MR analysis showed no mediating relationship among iron status, gut microbiota, and gastrointestinal diseases.Conclusion: This study provides evidence suggesting potential causal associations of iron status with gastrointestinal diseases and gut microbiota, especially liver disease.

Background: Ustekinumab (UST) is recommended as the first-line treatment for patients with moderate to severe Crohn’s disease (CD). However, the efficacy of certain patients may be suboptimal and necessitate intensive treatment or modification of the treatment regimen. We sought to establish a nomogram model to predict the short-term effectiveness of UST in moderate to severe CD patients. Methods: We established a derivation cohort comprising patients diagnosed with CD and treated with UST at the Sixth Affiliated Hospital of Sun Yat-sen University from May 2020 to July 2023. The patient data, including demographic and clinical characteristics as well as treatment details, were systematically collected. The achievement of clinical remission (defined as Crohn’s Disease Activity Index, CDAI < 150, without corticosteroid usage) after induction therapy was the endpoint observed during follow-up. Potential predictors were identified through the Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis. Subsequently, a multivariate logistic regression analysis was conducted to construct a nomogram model. The predictive accuracy and discriminative power of the model were assessed by Receiver Operating Characteristics (ROC) curves and calibration curves. Decision curve analysis (DCA) was employed to assess the clinical application value of the model. Results: 162 patients were included in the derivation cohort. The predictor’s selection was according to the minimum criteria. Prognostic factors, including duration, body mass index (BMI), smoking, extraintestinal manifestations (EIMs), perianal lesions (P), history of Vedolizumab therapy, and albumin levels (ALB), were identified and included in the nomogram. The model showed good discrimination and calibration on internal validation based on the bootstrap method (C-index: 0.843, 95% confidence interval: 0.768– 0.903). Moreover, DCA demonstrated that the nomogram was clinically beneficial. Conclusion: We constructed a practical tool to assist clinicians in identifying moderate to severe CD patients who are expected to have a good clinical response to UST, promoting personalized treatment and the development of precision medicine.

Two review articles in this collection systematically summarize the current state of research. The first, titled "Targeting gut microbiota dysbiosis in inflammatory bowel disease: a systematic review of current evidence," provides a comprehensive evaluation of therapeutic strategies aimed at modulating gut microbiota dysbiosis. The review emphasizes the potential of probiotics, prebiotics, fecal microbiota transplantation (FMT), and dietary interventions in restoring microbial balance and improving clinical outcomes in IBD patients. Notably, the authors highlight the promising results of FMT in inducing remission in ulcerative colitis, as supported by recent clinical trials (1).The second review, "Exploring the role of IL-1β in inflammatory bowel disease pathogenesis," delves into the role of the pro-inflammatory cytokine IL-1β in driving intestinal inflammation. The authors discuss how IL-1β contributes to mucosal barrier dysfunction, immune cell activation, and fibrosis in IBD. They also explore the potential of IL-1β-targeted therapies, such as anakinra and canakinumab, in mitigating disease severity. This review builds on previous findings that IL-1β signaling is a key mediator of inflammation in both Crohn's disease and ulcerative colitis (2).The original research articles in this collection offer groundbreaking insights into the metabolic and immunological aspects of the gut microbiota-gut-brain axis in IBD. The first study, "Alterations in tryptophan metabolism and de novo NAD+ biosynthesis within the microbiota-gut-brain axis in chronic intestinal inflammation," investigates the metabolic changes associated with chronic intestinal inflammation. The authors reveal significant alterations in tryptophan metabolism and NAD+ biosynthesis pathways, which are critical for maintaining intestinal homeostasis. These findings suggest that targeting these metabolic pathways could offer new therapeutic avenues for IBD management. This study aligns with earlier research demonstrating the role of tryptophan metabolites, such as kynurenine, in regulating immune responses and gut-brain communication (3).The second original study, "The association of three vaccination doses with reduced gastrointestinal symptoms after severe acute respiratory syndrome coronavirus 2 infections in patients with inflammatory bowel disease," examines the impact of COVID-19 vaccination on gastrointestinal symptoms in IBD patients. The findings indicate that three doses of mRNA vaccines are associated with a significant reduction in postinfection gastrointestinal symptoms, underscoring the importance of vaccination in this vulnerable population. This study adds to the growing body of evidence supporting the safety and efficacy of COVID-19 vaccines in IBD patients (4).The studies featured in this Research Topic not only deepen our understanding of the gut microbiota-gut-brain axis in IBD but also pave the way for future research and therapeutic innovations. For instance, the exploration of microbial metabolites, such as short-chain fatty acids (SCFAs) and secondary bile acids, holds promise for developing targeted therapies that restore gut-brain axis homeostasis. Additionally, the integration of multi-omics approaches, including metagenomics, metabolomics, and transcriptomics, could provide a more comprehensive understanding of the complex interactions underlying IBD pathogenesis.Moreover, the potential of psychobiotics-live microorganisms with mental health benefits-in modulating the gut-brain axis offers an exciting avenue for addressing the psychological comorbidities often associated with IBD, such as anxiety and depression.Recent studies have demonstrated the efficacy of certain probiotic strains, such as Lactobacillus and Bifidobacterium, in alleviating both gastrointestinal and neuropsychiatric symptoms in IBD patients (5).In conclusion, the gut microbiota-gut-brain axis represents a promising frontier in IBD research, offering novel insights into the disease's pathogenesis and potential therapeutic targets. The studies presented in this Research Topic underscore the importance of interdisciplinary approaches in unraveling the complexities of IBD and developing personalized treatment strategies. As research in this field continues to evolve, we anticipate significant advancements in precision medicine and improved quality of life for IBD patients.Finally, we extend our gratitude to all authors, reviewers, and readers for their invaluable contributions to this Research Topic. We hope that these findings will inspire further research and foster collaboration among scientists, clinicians, and patients to advance our understanding and management of IBD.