Integrated Analysis of Colorectal Cancer Reveals Cross-Cohort Gut Microbial Signatures and Associated Serum Metabolites.

BACKGROUND & AIMS: Studies have reported abnormal gut microbiota or circulating metabolome associated with colorectal cancer (CRC), but it remains a challenge to capture the CRC-relevant features consistent across geographic regions. This is particularly the problem for metabolic traits of CRC because the analyses generally use different platforms and laboratory methods, which poses a barrier to cross-dataset examination. In light of this, we sought to elucidate the microbial and metabolic signatures of CRC with broad population relevance. METHODS: In this integrated metagenomic (healthy controls [HC], n = 91; colorectal adenoma [CRA], n = 63; CRC, n = 71) and metabolomic (HC, n = 34; CRA, n = 31; CRC, n = 35) analysis, CRC-associated features and microbe-metabolite correlations were first identified from a Shanghai cohort. A gut microbial panel was trained in the in-house cohort and cross-validated in 7 published metagenomic datasets of CRC. The in-house metabolic connections to the cross-cohort microbial signatures were used as evidence to infer serum metabolites with potentially external relevance. In addition, a combined microbe-metabolite panel was produced for diagnosing CRC or adenoma. RESULTS: CRC-associated alterations were identified in the gut microbiome and serum metabolome. A composite microbe-metabolite diagnostic panel was developed and yielded an area under the curve of 0.912 for adenoma and 0.994 for CRC. We showed that many CRC-associated metabolites were linked to cross-cohort gut microbiome signatures of the disease, including CRC-enriched leucylalanine, serotonin, and imidazole propionate; and CRC-depleted perfluorooctane sulfonate, 2-linoleoylglycerol (18:2), and sphingadienine. CONCLUSIONS: We generated cross-cohort metagenomic signatures of CRC, some of which linked to in-house CRC-associated serum metabolites. The microbial and metabolic shifts may have wide population relevance.

Transformation of colitis and colorectal cancer: a tale of gut microbiota.

Intestinal inflammation modifies host physiology to promote the occurrence of colorectal cancer (CRC), as seen in colitis-associated CRC. Gut microbiota is crucial in cancer progression, primarily by inducing intestinal chronic inflammatory microenvironment, leading to DNA damage, chromosomal mutation, and alterations in specific metabolite production. Therefore, there is an increasing interest in microbiota-based prevention and treatment strategies, such as probiotics, prebiotics, microbiota-derived metabolites, and fecal microbiota transplantation. This review aims to provide valuable insights into the potential correlations between gut microbiota and colitis-associated CRC, as well as the promising microbiota-based strategies for colitis-associated CRC.

General Versus Neuraxial Anesthesia for Appendectomy: A Multicenter International Study.

BACKGROUND: In resource-limited countries, open appendectomy is still performed under general anesthesia (GA) or neuraxial anesthesia (NA). We sought to compare the postoperative outcomes of appendectomy under NA versus GA. METHODS: We conducted a post hoc analysis of the International Patterns of Opioid Prescribing (iPOP) multicenter study. All patients ≥ 16 years-old who underwent an open appendectomy between October 2016 and March 2017 in one of the 14 participating hospitals were included. Patients were stratified into two groups: NA-defined as spinal or epidural-and GA. All-cause morbidity, hospital length of stay (LOS), and pain severity were assessed using univariate analysis followed by multivariable logistic regression adjusting for the following preoperative characteristics: age, gender, body mass index (BMI), smoking, history of opioid use, emergency status, and country. RESULTS: A total of 655 patients were included, 353 of which were in the NA group and 302 in the GA group. The countries operating under NA were Colombia (39%), Thailand (31%), China (23%), and Brazil (7%). Overall, NA patients were younger (mean age (SD): 34.5 (14.4) vs. 40.7 (17.9), p-value < 0.001) and had a lower BMI (mean (SD): 23.5 (3.8) vs. 24.3 (5.2), p-value = 0.040) than GA patients. On multivariable analysis, NA was independently associated with less postoperative complications (OR, 95% CI: 0.30 [0.10-0.94]) and shorter hospital LOS (LOS > 3 days, OR, 95% CI: 0.47 [0.32-0.68]) compared to GA. There was no difference in postoperative pain severity between the two techniques. CONCLUSIONS: Open appendectomy performed under NA is associated with improved outcomes compared to that performed under GA. Further randomized controlled studies should examine the safety and value of NA in lower abdominal surgery.

Opioids After Surgery in the United States Versus the Rest of the World: The International Patterns of Opioid Prescribing (iPOP) Multicenter Study.

OBJECTIVE: The International Patterns of Opioid Prescribing study compares postoperative opioid prescribing patterns in the United States (US) versus the rest of the world. SUMMARY OF BACKGROUND DATA: The US is in the middle of an unprecedented opioid epidemic. Diversion of unused opioids contributes to the opioid epidemic. METHODS: Patients ≥16 years old undergoing appendectomy, cholecystectomy, or inguinal hernia repair in 14 hospitals from 8 countries during a 6-month period were included. Medical records were systematically reviewed to identify: (1) preoperative, intraoperative, and postoperative characteristics, (2) opioid intake within 3 months preoperatively, (3) opioid prescription upon discharge, and (4) opioid refills within 3 months postoperatively. The median/range and mean/standard deviation of number of pills and OME were compared between the US and non-US patients. RESULTS: A total of 4690 patients were included. The mean age was 49 years, 47% were female, and 4% had opioid use history. Ninety-one percent of US patients were prescribed opioids, compared to 5% of non-US patients (P < 0.001). The median number of opioid pills and OME prescribed were 20 (0-135) and 150 (0-1680) mg for US versus 0 (0-50) and 0 (0-600) mg for non-US patients, respectively (both P < 0.001). The mean number of opioid pills and OME prescribed were 23.1 ±â€Š13.9 in US and 183.5 ±â€Š133.7 mg versus 0.8 ±â€Š3.9 and 4.6 ±â€Š27.7 mg in non-US patients, respectively (both P < 0.001). Opioid refill rates were 4.7% for US and 1.0% non-US patients (P < 0.001). CONCLUSIONS: US physicians prescribe alarmingly high amounts of opioid medications postoperatively. Further efforts should focus on limiting opioid prescribing and emphasize non-opioid alternatives in the US.

Gut microbiota dysbiosis signature is associated with the colorectal carcinogenesis sequence and improves the diagnosis of colorectal lesions.

BACKGROUND AND AIM: The gut microbiota is associated with colorectal lesions in cases of precancer and colorectal cancer (CRC). However, there are apparent differences in studies on the gut microbiota in the pathogenic sequence from precancer to cancer. Here, we characterize the gut microbiota signatures of colorectal precancer and cancer and test their utility in detecting colorectal lesions in two independent Chinese cohorts. METHODS: Stool samples collected from patients with precancer and CRC were subjected to 16S ribosomal RNA gene sequencing and metagenomic shotgun sequencing analyses, which revealed the microbial signatures of the two disease stages. RESULTS: In comparison with healthy controls, lower microbial richness and diversity were observed in precancer and intensive interbacterial associations were found in CRC. We identified 41 bacteria that showed gradual increases while 12 bacteria showed gradual decreases at the genus level gradually during the development of CRC. Novel CRC-associated pathogenetic species were identified. Species units that contributed to altered microbial functions were identified in CRC patients and healthy controls. The microbial panel showed a comparable ability to fecal immunochemical test (FIT) in detecting CRC. However, the combination of microbes and FIT significantly improved the detection ability and sensitivity of colon lesions based on 18 genera. Microbial network analysis revealed a significant positive correlation among beneficial microbes and a negative correlation in detrimental phenotypes. CONCLUSIONS: Microbial dysbiosis was revealed in colorectal lesions. The combination of microbial markers and FIT improved the CRC detection ability, which might assist in the early diagnosis of CRC.

Minimally invasive treatment of mid-low rectovaginal fistula: a transanal endoscopic surgery study.

BACKGROUND: Treatment of rectovaginal fistulas (RVFs) is extremely difficult. No standard surgical procedure is accepted worldwide. The aim of this article was to evaluate a minimally invasive procedure for the repair of mid-low rectovaginal fistula. METHODS: This is a retrospective review of 17 patients who underwent minimally invasive surgery for the repair of mid-low rectovaginal fistulas (located in the lower or middle one-third of the vaginal wall) at our center between August 2016 and October 2018. The anal approach was adopted for 12 patients: 6 patients were treated directly by rectal mucosal advancement flap (RMAF) with transanal endoscopic surgery (TES), while the other 6 patients underwent initial TES exploration followed by RMAF procedure under direct vision. The vaginal approach was adopted for 5 patients: 3 patients were treated under TES directly and the other 2 were treated under direct vision after initial TES exploration. A total of 9 (52.94%) patients received diverting ileostomy-5 anal approach patients and 4 vaginal approach patients. RESULTS: Median age of the patients was 46 years (range 10-76 years), and median BMI was 21.9 (range 17.9-28.1). Median operative time was 75 min (range 60-120 min), and median duration of postoperative hospital stay was 8 days (range 6-15 days). Recurrence was seen in 3/12 anal approach patients vs. 0/5 vaginal approach patients. Both the median preoperative and the median postoperative Wexner score were 0 (range 0-2). The median follow-up time was 8 months (range 2-24). No severe complications occurred in any patient. CONCLUSION: The TES procedure for the treatment of mid-low rectovaginal fistulas avoids any incision of the abdomen and perineal area and appears to be a safe and feasible procedure. This minimally invasive technique is still evolving and is likely to gain wide acceptance in the near future.

Dynamic signatures of gut microbiota and influences of delivery and feeding modes during the first 6 months of life.

The gut microbiota of infants changes over time and is affected by various factors during early life. However, rarely have studies explored the gut microbiota development and affecting factors in the Chinese infant population. We enrolled 102 infants and collected stool samples from them at birth, 42 days, 3 mo, and 6 mo after delivery to characterize the microbiota signatures and the effects of different factors that modulate the gut microbiota diversity, composition, and function over time. DNA extracted from the bacteria in the stool samples was subjected to high-throughput sequencing and bioinformatics analysis. Microbial richness and diversity increased significantly during the first 6 mo of life. Beneficial microbes such as Bifidobacterium, Lactobacillus, and Blautia were found to be increased in the infant's gut at 6 mo, while pathological bacteria such as Escherichia-Shigella, Enterobacter, Staphylococcus, and Klebsiella decreased over time. The changes in the infant delivery mode and infant-feeding mode only produced changes in the microbial composition, whereas changes in bacterial richness, diversity and effects sizes on the microbial architecture were all time dependent. A comparison of infant delivery modes conveyed a decrease in abundance of Bacteroidetes over time in the gut of infants born via C-section, while the Bifidobacterium was the most dominant genus in the vaginal delivery group. The gut microbiota of infants changed extensively during the first 6 mo of life. Delivery and feeding modes were strong factors that significantly affected microbial architecture and functions.

Dysbiosis signatures of gut microbiota in coronary artery disease.

Gut microbiota dysbiosis has been considered to be an important risk factor that contributes to coronary artery disease (CAD), but limited evidence exists about the involvement of gut microbiota in the disease. Our study aimed to characterize the dysbiosis signatures of gut microbiota in coronary artery disease. The gut microbiota represented in stool samples were collected from 70 patients with coronary artery disease and 98 healthy controls. 16S rRNA sequencing was applied, and bioinformatics methods were used to decipher taxon signatures and function alteration, as well as the microbial network and diagnostic model of gut microbiota in coronary artery disease. Gut microbiota showed decreased diversity and richness in patients with coronary artery disease. The composition of the microbial community changed; Escherichia-Shigella [false discovery rate (FDR = 7.5*10-5] and Enterococcus (FDR = 2.08*10-7) were significant enriched, while Faecalibacterium (FDR = 6.19*10-10), Subdoligranulum (FDR = 1.63*10-6), Roseburia (FDR = 1.95*10-9), and Eubacterium rectale (FDR = 2.35*10-4) were significant depleted in the CAD group. Consistent with the taxon changes, functions such as amino acid metabolism, phosphotransferase system, propanoate metabolism, lipopolysaccharide biosynthesis, and protein and tryptophan metabolism were found to be enhanced in CAD patients. The microbial network revealed that Faecalibacterium and Escherichia-Shigella were the microbiotas that dominated in the healthy control and CAD groups, respectively. The microbial diagnostic model based on random forest also showed probability in identifying those who suffered from CAD. Our study successfully identifies the dysbiosis signature, dysfunctions, and comprehensive networks of gut microbiota in CAD patients. Thus, modulation targeting the gut microbiota may be a novel strategy for CAD treatment.

Fusobacterium nucleatum Increases Proliferation of Colorectal Cancer Cells and Tumor Development in Mice by Activating Toll-Like Receptor 4 Signaling to Nuclear Factor-κB, and Up-regulating Expression of MicroRNA-21.

BACKGROUND & AIMS: Nearly 20% of the global cancer burden can be linked to infectious agents. Fusobacterium nucleatum promotes tumor formation by epithelial cells via unclear mechanisms. We aimed to identify microRNAs (miRNAs) induced by F nucleatum and evaluate their ability to promote colorectal carcinogenesis in mice. METHODS: Colorectal cancer (CRC) cell lines were incubated with F nucleatum or control reagents and analyzed in proliferation and would healing assays. HCT116, HT29, LoVo, and SW480 CRC cell lines were incubated with F nucleatum or phosphate-buffered saline (PBS [control]) and analyzed for miRNA expression patterns and in chromatin immunoprecipitation assays. Cells were incubated with miRNAs mimics, control sequences, or small interfering RNAs; expression of reporter constructs was measured in luciferase assays. CRC cells were incubated with F nucleatum or PBS and injected into BALB/C nude mice; growth of xenograft tumors was measured. C57BL adenomatous polyposis colimin/+, C57BL miR21a-/-, and C57BL mice with full-length miR21a (controls) were given F nucleatum by gavage; some mice were given azoxymethane and dextran sodium sulfate to induce colitis and colon tumors. Intestinal tissues were collected and tumors were counted. Serum samples from mice were analyzed for cytokine levels by enzyme-linked immunosorbent assay. We performed in situ hybridization analyses to detect enrichment of F nucleatum in CRC cells. Fusobacterium nucleatum DNA in 90 tumor and matched nontumor tissues from patients in China were explored for the expression correlation analysis; levels in 125 tumor tissues from patients in Japan were compared with their survival times. RESULTS: Fusobacterium nucleatum increased proliferation and invasive activities of CRC cell lines compared with control cells. CRC cell lines infected with F nucleatum formed larger tumors, more rapidly, in nude mice than uninfected cells. Adenomatous polyposis colimin/+ mice gavaged with F nucleatum developed significantly more colorectal tumors than mice given PBS and had shorter survival times. We found several inflammatory factors to be significantly increased in serum from mice given F nucleatum (interleukin 17F, interleukin 21, and interleukin 22, and MIP3A). We found 50 miRNAs to be significantly up-regulated and 52 miRNAs to be significantly down-regulated in CRCs incubated with F nucleatum vs PBS; levels of miR21 increased by the greatest amount (>4-fold). Inhibitors of miR21 prevented F nucleatum from inducing cell proliferation and invasion in culture. miR21a-/- mice had a later appearance of fecal blood and diarrhea after administration of azoxymethane and dextran sodium sulfate, and had longer survival times compared with control mice. The colorectum of miR21a-/- mice had fewer tumors, of smaller size, and the miR21a-/- mice survived longer than control mice. We found RASA1, which encodes an RAS GTPase, to be one of the target genes consistently down-regulated in cells that overexpressed miR21 and up-regulated in cells exposed to miR21 inhibitors. Infection of cells with F nucleatum increased expression of miR21 by activating Toll-like receptor 4 signaling to MYD88, leading to activation of the nuclear factor-κB. Levels of F nucleatum DNA and miR21 were increased in tumor tissues (and even more so in advanced tumor tissues) compared with non-tumor colon tissues from patients. Patients whose tumors had high amounts of F nucleatum DNA and miR21 had shorter survival times than patients whose tumors had lower amounts. CONCLUSIONS: We found infection of CRC cells with F nucleatum to increase their proliferation, invasive activity, and ability to form xenograft tumors in mice. Fusobacterium nucleatum activates Toll-like receptor 4 signaling to MYD88, leading to activation of the nuclear factor-κB and increased expression of miR21; this miRNA reduces levels of the RAS GTPase RASA1. Patients with both high amount of tissue F nucleatum DNA and miR21 demonstrated a higher risk for poor outcomes.

Micro Integral Membrane Protein (MIMP), a Newly Discovered Anti-Inflammatory Protein of Lactobacillus Plantarum, Enhances the Gut Barrier and Modulates Microbiota and Inflammatory Cytokines.

BACKGROUND/AIMS: Recent studies have demonstrated that the manipulation of the gut microbiome represents a promising treatment for inflammatory bowel disease (IBD). We previously identified micro integral membrane protein (MIMP) as the smallest domain of surface layer protein from Lactobacillus Plantarum. However, the therapeutic relevance of MIMP in IBD remains unknown. METHODS: We initially employed a dextran sodium sulphate (DSS)-induced colitis model and evaluated the effect of MIMP on the inflammation response, intestinal barrier and gut microbiota using histological examination, Fluorescein isothiocyanate-Dextran detection and pyrosequencing analysis respectively. We then established peripheral blood mononuclear cells (PBMCs) and an epithelial CaCO-2 co-culture model to investigate the regulatory role of MIMP in inflammatory cytokines. The level changes of inflammatory cytokines were detected using Enzyme-linked immunosorbent and real-time polymerase chain reaction assay. The involved regulatory mechanisms were investigated mainly using dual luciferase reporter and chromatin immunoprecipitation assay. RESULTS: In the DSS-induced colitis model, we observed that MIMP intervention effectively improved the body weight loss, increased the colon length and decreased disease activity index. Consistently, the inflammation scores in the MIMP treatment group were significantly lower than those in the DSS treatment group. Furthermore, MIMP intervention was found to successfully neutralize DSS treatment by decreasing the expression of pro-inflammatory cytokines (IFN-γ, IL-17 and IL-23) and increasing the expression of anti-inflammatory cytokines (IL-4 and IL-10). Notably, the permeability assay demonstrated that the MIMP treatment group was remarkably lower than that in the DSS treatment group. We also showed that MIMP improved gut microbiota dysbiosis caused by DSS-induced inflammation. Additionally, in PBMCs and the CaCO-2 co-culture model, MIMP showed an obvious suppressive effect on lipopolysaccharide-induced inflammation in a time- and dose-dependent manner. Furthermore, we revealed that MIMP could modulate inflammatory cytokine expression through the toll-like receptor 4 pathway and histone acetylation. CONCLUSIONS: Our results suggested that MIMP showed a significant anti-inflammatory effect through regulating the gut barrier, microbiota and inflammatory cytokines. MIMP may have translational relevance as clinically relevant therapy for IBD patients.

Novel evidence for an oncogenic role of microRNA-21 in colitis-associated colorectal cancer.

OBJECTIVE: miR-21 was found to be overexpressed in the colon tissues and serum of patients with UC and colorectal cancer (CRC); however, the exact roles of miR-21 in colitis-associated CRC remain unclear. The aim of our study was to investigate the biological mechanisms of miR-21 in colitis-associated colon cancer (CAC). DESIGN: miR-21 expression was examined in the tumours of 62 patients with CRC from China and 37 colitis-associated neoplastic tissues from Japan and Austria. The biological functions of miR-21 were studied using a series of in vitro, in vivo and clinical approaches. RESULTS: miR-21 levels were markedly upregulated in the tumours of 62 patients with CRC, 22 patients with CAC, and in a mouse model of CAC. Following azoxymethane and dextran sulfate sodium intervention, miR-21-knockout mice showed reduced expression of proinflammatory and procarcinogenic cytokines (interleukin (IL) 6, IL-23, IL-17A and IL-21) and a decrease in the size and number of tumours compared with the control mouse group. The absence of miR-21 resulted in the reduced expression of Ki67 and the attenuated proliferation of tumour cells with a simultaneous increase in E-cadherin and decrease in ß-catenin and SOX9 in the tumours of CAC mice. Furthermore, the absence of miR-21 increased the expression of its target gene PDCD4 and subsequently modulated nuclear factor (NF)-κB activation. Meanwhile, miR-21 loss reduced STAT3 and Bcl-2 activation, causing an increase in the apoptosis of tumour cells in CAC mice. CONCLUSIONS: These observations provide novel evidence for miR-21 blockade to be a key strategy in reducing CAC.

Predicting short-term major postoperative complications in intestinal resection for Crohn's disease: A machine learning-based study.

BACKGROUND: Due to the complexity and numerous comorbidities associated with Crohn's disease (CD), the incidence of postoperative complications is high, significantly impacting the recovery and prognosis of patients. Consequently, additional studies are required to precisely predict short-term major complications following intestinal resection (IR), aiding surgical decision-making and optimizing patient care. AIM: To construct novel models based on machine learning (ML) to predict short-term major postoperative complications in patients with CD following IR. METHODS: A retrospective analysis was performed on clinical data derived from a patient cohort that underwent IR for CD from January 2017 to December 2022. The study participants were randomly allocated to either a training cohort or a validation cohort. The logistic regression and random forest (RF) were applied to construct models in the training cohort, with model discrimination evaluated using the area under the curves (AUC). The validation cohort assessed the performance of the constructed models. RESULTS: Out of the 259 patients encompassed in the study, 5.0% encountered major postoperative complications (Clavien-Dindo ≥ III) within 30 d following IR for CD. The AUC for the logistic model was 0.916, significantly lower than the AUC of 0.965 for the RF model. The logistic model incorporated a preoperative CD activity index (CDAI) of ≥ 220, a diminished preoperative serum albumin level, conversion to laparotomy surgery, and an extended operation time. A nomogram for the logistic model was plotted. Except for the surgical approach, the other three variables ranked among the top four important variables in the novel ML model. CONCLUSION: Both the nomogram and RF exhibited good performance in predicting short-term major postoperative complications in patients with CD, with the RF model showing more superiority. A preoperative CDAI of ≥ 220, a diminished preoperative serum albumin level, and an extended operation time might be the most crucial variables. The findings of this study can assist clinicians in identifying patients at a higher risk for complications and offering personalized perioperative management to enhance patient outcomes.

Overexpression of miR-21 in patients with ulcerative colitis impairs intestinal epithelial barrier function through targeting the Rho GTPase RhoB.

Although epithelial barrier dysfunction in the gut has been extensively reported in ulcerative colitis (UC), the pathogenesis of this disease is not completely understood. In the present study, we investigated the role of miR-21 in regulating intestinal epithelial barrier function in UC. Colonic biopsies were obtained from 30 chronic UC patients and 30 healthy controls. Using real-time quantitative polymerase chain reaction (qRT-PCR), we found that both the mucosal and serum levels of miR-21 were upregulated in UC. In situ hybridization (ISH) analysis confirmed the accumulation of miR-21 in UC epithelia cells in vivo. Immunohistochemistry, Western Blot, qRT-PCR, and ultrastructural analyses further demonstrated that the overexpression of miR-21 in UC mucosa and Caco-2 cells impaired the integrity of the tight junctions, resulted in a decrease of the transepithelial electrical resistance (TER) and an increase of the inulin permeability. Furthermore, miR-21 induced the degradation of RhoB mRNA, which led to the depletion of RhoB and the impairment of tight junctions in intestinal epithelial cells.

The role of gut microbiota in the pathogenesis of colorectal cancer.

The human gastrointestinal tract harbors a complex and abundant microbial community that can reach levels as high as 10(13)-10(14) microorganisms in the colon. These microorganisms are essential to a host's well-being in terms of nutrition and mucosa immunity. However, numerous studies have also implicated members of the colonic microbiota in the development of colorectal cancer (CRC). While CRC involves a genetic component where damaged DNA and genetic instability initiates a malignant transformation, environmental factors can also contribute to the onset of CRC. Furthermore, considering the constant exposure of the colonic mucosa to the microbiome and/or its metabolites, the mucosa has long been proposed to contribute to colon tumorigenesis. However, the mechanistic details of these associations remain unknown. Fortunately, due to technical and conceptual advances, progress in characterizing the taxonomic composition, metabolic capacity, and immunomodulatory activity of human gut microbiota have been made, thereby elucidating its role in human health and disease. Furthermore, the use of experimental animal models and clinical/epidemiological studies of environmental etiological factors has identified a correlation between gut microbiota composition and gastrointestinal cancers. Bacteria continuously stimulate activated immunity in the gut mucosa and also contribute to the metabolism of bile and food components. However, the highest levels of carcinogen production are also associated with gut anaerobic bacteria and can be lowered with live lactobacilli supplements. In this review, evidence regarding the relationship between microbiota and the development of CRC will be discussed, as well as the role for microbial manipulation in affecting disease development.

Gut microbiota in brain tumors: An emerging crucial player.

In recent decades, various roles of the gut microbiota in physiological and pathological conditions have been uncovered. Among the many interacting pathways between the host and gut flora, the gut-brain axis has drawn increasing attention and is generally considered a promising way to understand and treat brain tumors, one of the most lethal neoplasms. In this narrative review, we aimed to unveil and dissect the sophisticated mechanisms by which the gut-brain axis exerts its influence on brain tumors. Furthermore, we summarized the latest research regarding the gastrointestinal microbial landscape and the effect of gut-brain axis malfunction on different brain tumors. Finally, we outlined the ongoing developing approaches of microbial manipulation and their corresponding research related to neuro-malignancies. Collectively, we recapitulated the advances in gut microbial alterations along with their potential interactive mechanisms in brain tumors and encouraged increased efforts in this area.

Nodal promotes colorectal cancer survival and metastasis through regulating SCD1-mediated ferroptosis resistance.

Re-expression of an embryonic morphogen, Nodal, has been seen in several types of malignant tumours. By far, studies about Nodal's role in colorectal cancer (CRC) remain limited. Ferroptosis is essential for CRC progression, which is caused by cellular redox imbalance and characterized by lipid peroxidation. Herein, we observed that Nodal enhanced CRC cell's proliferative rate, motility, invasiveness, and epithelial-mesenchymal transition (EMT) in vivo and in vitro. Notably, Nodal overexpression induced monounsaturated fatty acids synthesis and increased the lipid unsaturation level. Nodal knockdown resulted in increased CRC cell lipid peroxidation. Stearoyl-coenzyme A desaturase 1 (SCD1) inhibition at least partially abolished the resistance of Nodal-overexpressing cells to RSL3-induced ferroptosis. Mechanistically, SCD1 was transcriptionally up-regulated by Smad2/3 pathway activation in response to Nodal overexpression. Significant Nodal and SCD1 up-regulation were observed in CRC tissues and were associated with CRC metastasis and poor clinical outcomes. Furthermore, bovine serum albumin nanoparticles/si-Nodal nanocomplexes targeting Nodal had anti-tumour effects on CRC progression and metastasis. This research elucidated the role of Nodal in CRC development and revealed a potential gene-based therapeutic strategy targeting Nodal for improving CRC treatment.

Methionine restriction promotes cGAS activation and chromatin untethering through demethylation to enhance antitumor immunity.

Cyclic GMP-AMP synthase (cGAS) is the major sensor for cytosolic DNA and activates type I interferon signaling and plays an essential role in antitumor immunity. However, it remains unclear whether the cGAS-mediated antitumor activity is affected by nutrient status. Here, our study reports that methionine deprivation enhances cGAS activity by blocking its methylation, which is catalyzed by methyltransferase SUV39H1. We further show that methylation enhances the chromatin sequestration of cGAS in a UHRF1-dependent manner. Blocking cGAS methylation enhances cGAS-mediated antitumor immunity and suppresses colorectal tumorigenesis. Clinically, cGAS methylation in human cancers correlates with poor prognosis. Thus, our results indicate that nutrient stress promotes cGAS activation via reversible methylation, and suggest a potential therapeutic strategy for targeting cGAS methylation in cancer treatment.

Timing of individualized surgical intervention in Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract with an increasing incidence worldwide. Comprehensive therapy for CD focuses on symptom control and healing the intestinal mucosa to improve the quality of life and prevent complications. Surgical intervention plays a vital role in comprehensive therapy. However, deciding the optimal timing for surgical intervention has long been a focus of controversy. This review provides insights into the timing of surgery for CD and guides clinicians in daily treatment.

Crohn's Disease Complicated by Rare Types of Intestinal Obstruction: Two Case Reports.

Intestinal obstruction is one of the most common complications of Crohn's disease (CD), jeopardizing the quality of life of patients. Numerous factors may contribute to intestinal obstruction in CD. Thus far, the primary reason has been identified as intestinal fibrosis caused by repeated chronic inflammation during the active phase of CD. Herein, we report two rare complicated CD cases and provide a reference for the clinical diagnosis and treatment of similar patients. Case one involves capsule endoscope retention in the small intestine of one CD patient concurrent with intestinal obstruction. Case two is a CD patient with intestinal obstruction caused by a mesangial hernia and ileal stenosis. Individualized and minimally invasive surgical intervention ultimately resulted in the successful management of these two patients. The two cases serve as an excellent guide for diagnosing and treating CD patients who present with similar symptoms.