Background: Pneumatosis cystoides intestinalis (PCI) is a low-incidence disease that confuses many doctors. A vast number of factors are suspected to contribute to its pathogenesis, such as Crohn’s disease, intestinal stenosis, ulcerative colitis, drug use, extra-gastrointestinal diseases, and chronic obstructive pulmonary disease. Most consider its pathogenesis interrelated to an increase in intra-intestinal pressure and the accumulation of gas produced by aerogenic bacteria, and patients with atypical symptoms and imaging manifestations tend to be misdiagnosed. Case presentation: A 64-year-old man complained of a 3-month history of bloody stool without mucopurulent discharge, abdominal pain, or diarrhea. Colonoscopy revealed multiple nodular projections into the segmental mucosa of the sigmoid colon. Crohn’s disease and malignant disease ware suspected first according to the patient’s history, but laboratory examinations did not confirm either. Endoscopic ultrasound (EUS) revealed multiple cystic lesions in the submucosa. Moreover, computer tomography scan showed multiple bubble-like cysts. Combined with ultrasonography, computed tomography, and pathology findings, we ultimately made a diagnosis of PCI. Instead of surgery, we recommended conservative treatment consisting of endoscopy and oral drug administration. His symptoms improved with drug therapy after discharge, and no recurrence was noted on follow-up. Conclusions: The incidence of PCI is low. Due to a lack of specificity in clinical manifestations and endoscopic findings, it often misdiagnosed as intestinal polyps, tumors, inflammatory bowel disease, or other conditions. Colonoscopy, computed tomography, and ultrasonography have demonstrated benefit in patients with multiple nodular projections in colon. Compared to the treatment of the above diseases, PCI treatment is effective and convenient, and the prognosis is optimistic. Therefore, clinicians should increase their awareness of PCI to avoid unnecessary misdiagnosis.

Crohn's Disease (CD) is a chronic inflammatory condition characterized by intestinal fibrosis, severely impacting patient quality of life. The molecular mechanisms driving this fibrosis remain inadequately understood. Recent evidence implicates mesenteric adipose tissue (MAT) in CD pathogenesis, particularly through its exosome secretion, which may influence fibrogenic pathways. Understanding the role of MAT-derived exosomes is crucial for unraveling these molecular processes. This study aims to elucidate the role of MAT-derived exosomes in CD-related intestinal fibrosis. We focus on investigating their molecular composition and the potential impact on fibrosis progression, with an emphasis on identifying novel therapeutic targets. We induced chronic intestinal inflammation in mice using dinitrobenzene sulfonic acid (DNBS), simulating CD-like fibrosis. Exosomes were isolated from DNBS-treated mice (MG) and normal controls (NG) for characterization using electron microscopy and proteomic analysis. Additionally, human colonic fibroblasts were exposed to exosomes from CD patients and healthy individuals, with subsequent assessment of fibrogenesis through proteomic and RNA sequencing analyses. Proteomic analyses revealed a significant activation of the TGF-β signaling pathway in MG-treated mice compared to controls, correlating with enhanced intestinal fibrosis. In vitro experiments demonstrated that colonic fibroblasts exposed to CD patient-derived exosomes exhibited increased fibrogenic activity. Protein docking and co-immunoprecipitation studies suggested a critical interaction between TINAGL1 and SMAD4, enhancing fibrosis. Importantly, in vivo experiments corroborated that recombinant TINAGL1 protein exacerbated DNBS-induced intestinal fibrosis. Our findings highlight the pivotal role of MAT-derived exosomes, particularly those carrying TINAGL1, in the progression of intestinal fibrosis in CD. The involvement of the TGF-β signaling pathway, especially the SMAD4 protein, offers new insights into the molecular mechanisms of CD-related fibrosis and presents potential targets for therapeutic intervention.

Objective: To explore the clinical value of fecal calprotectin (FC) for evaluating disease activity in patients with Crohn’s disease (CD) and its relationship with disease location.Methods: Patients with CD were enrolled retrospectively, and clinical data, including FC levels, were collected. Clinical activity was assessed using the Crohn’s disease activity index (CDAI). Endoscopic activity was assessed using a simple endoscopic score for Crohn’s disease (SES-CD). The partial SES-CD (pSES-CD) was scored for the size of ulcers in each segment as defined by the SES-CD and was calculated as the sum of segmental ulcer scores.Results: This study included 273 CD patients. The FC level was significantly positively correlated with the CDAI and SES-CD, with correlation coefficients of 0.666 and 0.674, respectively. The median FC levels in patients with clinical remission and mildly active and moderately–severely active disease were 41.01, 164.20, and 444.45 μg/g. These values were 26.94, 66.77, and 327.22 μg/g during endoscopic remission and mildly and moderately–severely active stages, respectively. Compared with c-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and other biomarker parameters, FC was better at predicting disease activity for CD patients. For an FC <74.52 μg/g, the area under the curve (AUC) for predicting clinical remission was 0.86, with a sensitivity of 89.47% and a specificity of 71.70%. Moreover, endoscopic remission was predicted with a sensitivity of 68.02% and a specificity of 85.53%. The AUC was 0.83, and the cutoff value was 80.84 μg/g. In patients with ileal and (ileo) colonic CD, FC was significantly correlated with the CDAI, SES-CD, and pSES-CD. The correlation coefficients were 0.711 (CDAI), 0.473 (SES-CD), and 0.369 (pSES-CD) in patients with ileal CD and 0.687, 0.745, and 0.714 in patients with (ileo) colonic CD, respectively. For patients in remission, those in the active stage, and those with large or very large ulcers, differences in FC levels were not significant between patients with ileal and (ileo) colonic CD.Conclusion: FC is a reliable predictor of disease activity in patients with CD, including those with ileal CD. FC is thus recommended for the routine follow-up of patients with CD.

Ulcerative colitis (UC) is a chronic inflammatory disorder marked by epithelial barrier disruption and defective resolution of inflammation. Although epithelial apoptosis and impaired efferocytosis are recognized contributors to disease progression, their molecular regulation remains insufficiently defined. NR1D1, a circadian transcriptional repressor implicated in immune control, has not been fully explored in UC. Here, this study shows that NR1D1 expression is markedly reduced in human UC biopsies and murine colitis. CUT&Tag profiling revealed direct NR1D1 chromatin occupancy, while ChIP–qPCR and luciferase assays confirmed that NR1D1 represses CD47, a key anti‐efferocytosis molecule. Functional experiments demonstrate that NR1D1 deficiency enhances epithelial apoptosis, upregulates CD47, impairs macrophage efferocytosis, and exacerbates colitis in IEC‐specific Nr1d1 ^−/− mice. To restore NR1D1 activity, a hydrogel (HA@Alg‐ADAP‐SR9011) combining Andrias davidianus peptides is engineered with the NR1D1 agonist SR9011 for targeted, sustained intestinal delivery. In DSS‐induced colitis, hydrogel‐mediated SR9011 suppresses inflammation, reduces CD47, preserves epithelial integrity, and improves histological outcomes. Single‐cell RNA sequencing further reveals reduced CD47 and enhances efferocytic signatures in SR9011‐treated tissues. While pharmacokinetic analyses are limited to colonic tissue, these findings establish NR1D1 as a central regulator of epithelial turnover and efferocytosis in UC and support hydrogel‐based NR1D1 activation as a therapeutic strategy.