BACKGROUND: Inflammatory bowel disease, particularly Crohn\'s disease (CD), has been associated with alterations in mesenteric adipose tissue (MAT) and the phenomenon termed \"creeping fat\". Histopathological evaluations showed that MAT and intestinal tissues were significantly altered in patients with CD, with these tissues characterized by inflammation and fibrosis.
OBJECTIVE: To evaluate the complex interplay among MAT, creeping fat, inflammation, and gut microbiota in CD.
METHODS: Intestinal tissue and MAT were collected from 12 patients with CD. Histological manifestations and protein expression levels were analyzed to determine lesion characteristics. Fecal samples were collected from five recently treated CD patients and five control subjects and transplanted into mice. The intestinal and mesenteric lesions in these mice, as well as their systemic inflammatory status, were assessed and compared in mice transplanted with fecal samples from CD patients and control subjects.
RESULTS: Pathological examination of MAT showed significant differences between CD-affected and unaffected colons, including significant differences in gut microbiota structure. Fetal microbiota transplantation (FMT) from clinically healthy donors into mice with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD ameliorated CD symptoms, whereas FMT from CD patients into these mice exacerbated CD symptoms. Notably, FMT influenced intestinal permeability, barrier function, and levels of proinflammatory factors and adipokines. Furthermore, FMT from CD patients intensified fibrotic changes in the colon tissues of mice with TNBS-induced CD.
CONCLUSIONS: Gut microbiota play a critical role in the histopathology of CD. Targeting MAT and creeping fat may therefore have potential in the treatment of patients with CD.

BACKGROUND: Heterotopic mesenteric ossification (HMO) is a clinically rare condition characterized by the formation of bone tissue in the mesentery. The worldwide reporting of such cases is limited to just over 70 instances in the medical literature. The etiology of HMO remains unclear, but the disease is possibly induced by mechanical trauma, ischemia, or intra-left lower quadrant abdominal infection, leading to the differentiation of mesenchymal stem cells into osteoblasts. Here, we present a rare case of HMO that occurred in a 34-year-old male, who presented with left lower quadrant abdominal pain.
METHODS: We report the case of a 34-year-old male patient who presented with left lower abdominal pain following trauma to the left lower abdomen. He subsequently underwent surgical treatment, and the postoperative pathological diagnosis was HMO.
CONCLUSIONS: We believe that although there is limited literature and research on HMO, when patients with a history of trauma or surgery to the left lower abdomen present with corresponding imaging findings, clinicians should be vigilant in distinguishing this condition and promptly selecting appropriate diagnostic and therapeutic interventions.

In this report, we present an Asian male patient who was 30 years old and admitted to the hospital due to pancreatitis. While undergoing a CT scan, an isolated mass was unexpectedly discovered in the patient\'s abdomen. The patient\'s abdominal pain, which was caused by pancreatitis, had resolved before he underwent surgical resection to remove the mass. Subsequently, the patient was diagnosed with Castleman disease based on pathology. Castleman disease occurring in the mesentery is exceptionally rare. Therefore, we have reviewed the essential information regarding Castleman disease and have found that the crucial part lies in the diagnosis and the consideration of distinct treatment strategies based on different types.

BACKGROUND: Diffuse intestinal and mesenteric lipomatosis is a rare condition characterized by the overgrowth of adipose tissue in the intestines and mesentery. This case report aims to highlight the rare occurrence of chronic abdominal distention caused by this disease and its unique invasion into the muscle layer, which has not been previously reported.
METHODS: A 36-year-old woman with a 7-year history of abdominal distension was admitted to our hospital\'s Department of Gastrointestinal Surgery.
METHODS: Abdominal and pelvic computed tomography revealed diffuse small intestinal lipomatosis.
METHODS: The patient underwent surgery. We performed an open-field ilectomy involving removal of all lipomatous intestines (250 cm).
RESULTS: During the surgery, diffuse nodular ileal and mesenteric lipomatosis was confirmed, characterized by the presence of multiple nodular lipomas within the submucosal and muscular layers. The surgical intervention involved the resection of 250 cm of the affected ileum, followed by jejunoileal anastomosis. Postoperative pathology confirmed the diagnosis, with lesions observed in both the submucosa and muscle layers. The patient showed significant improvement in symptoms, with normal intestinal function and weight gain observed over a 10-month follow-up period, and no signs of recurrence.
CONCLUSIONS: Diffuse intestinal and mesenteric lipomatosis can lead to long-term abdominal distension. Additionally, it may be involved in the muscle layer of the intestinal wall. Surgery is the primary treatment option for symptomatic intestinal lipomatosis.

OBJECTIVE: Exosome-based therapies are gaining increasing attention, with growing evidence suggesting a link between alterations in mesentery adipose tissue (MAT) and intestinal disease in Crohn\'s disease (CD). However, the specific mechanism by which mesenchymal stem cells (MSCs)-Exos may alleviate colitis through targeting MAT remains not fully understood.
METHODS: Human umbilical cord MSCs (HucMSCs) were cultured to isolate the corresponding exosomes (HucMSCs-Exos), which were confirmed by their morphology, size distribution, and expression of markers. In vivo, 2,4,6-trinitrobenzenesulfonic acid solution (TNBS) and dextran sodium sulfate (DSS) -induced mouse colitis models were used to detect the therapeutic effects of HucMSCs-Exos. ELISA, qRT-PCR, western blotting, and immunofluorescence determined the expression of key molecules. Luciferase reporter assay was used to confirm the relationship between miR-21-5p and SPRY2.
RESULTS: Exosomes treatment through mesenteric injection demonstrated therapeutic effects on mesenteric inflammation and colitis. These therapeutic benefits were contingent on macrophages, significantly facilitating the M2 polarization of mesenteric macrophages. The expression data from GSE159814 and GSE211008 revealed that exosomal miR-21-5p was enriched in HucMSCs-Exos and could be delivered to macrophages. Additionally, the results indicated that miR-21-5p could directly target the 3\'UTR of SPRY2 and activate the phosphorylation of ERK to modify macrophage phenotypes. Mechanistically, exosomal miR-21-5p derived from HucMSCs could promote macrophage M2 polarization via the SPRY2/ERK axis.
CONCLUSIONS: Mesenteric injection of HucMSCs-Exos significantly alleviates mesenteric inflammation and colitis by promoting mesenteric macrophage M2 polarization, making it a promising approach to treat colitis and suggesting therapeutic potential role of exosomal miR-21-5p in CD.

BACKGROUND: Mesenchymal stem cells (MSCs) demonstrate a wide range of therapeutic capabilities in the treatment of inflammatory bowel disease (IBD). The intraperitoneal injection of MSCs has exhibited superior therapeutic efficacy on IBD than intravenous injection. Nevertheless, the precise in vivo distribution of MSCs and their biological consequences following intraperitoneal injection remain inadequately understood. Additional studies are required to explore the correlation between MSCs distribution and their biological effects.
METHODS: First, the distribution of human umbilical cord MSCs (hUC-MSCs) and the numbers of Treg and Th17 cells in mesenteric lymph nodes (MLNs) were analyzed after intraperitoneal injection of hUC-MSCs. Subsequently, the investigation focused on the levels of transforming growth factor beta1 (TGF-β1), a key cytokine to the biology of both Treg and Th17 cells, in tissues of mice with colitis, particularly in MLNs. The study also delved into the impact of hUC-MSCs therapy on Treg cell counts in MLNs, as well as the consequence of TGFB1 knockdown hUC-MSCs on the differentiation of Treg cells and the treatment of IBD.
RESULTS: The therapeutic effectiveness of intraperitoneally administered hUC-MSCs in the treatment of colitis was found to be significant, which was closely related to their quick migration to MLNs and secretion of TGF-β1. The abundance of hUC-MSCs in MLNs of colitis mice is much higher than that in other organs even the inflamed sites of colon. Intraperitoneal injection of hUC-MSCs led to a significant increase in the number of Treg cells and a decrease in Th17 cells especially in MLNs. Furthermore, the concentration of TGF-β1, the key cytokine for Treg differentiation, were also found to be significantly elevated in MLNs after hUC-MSCs treatment. Knockdown of TGFB1 in hUC-MSCs resulted in a noticeable reduction of Treg cells in MLNs and the eventually failure of hUC-MSCs therapy in colitis.
CONCLUSIONS: MLNs may be a critical site for the regulatory effect of hUC-MSCs on Treg/Th17 cells and the therapeutic effect on colitis. TGF-β1 derived from hUC-MSCs promotes local Treg differentiation in MLNs. This study will provide new ideas for the development of MSC-based therapeutic strategies in IBD patients.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease where the body loses tolerance to its own antigens, particularly nuclear antigens. Abnormal responses from T and B cells lead to the production of autoantibodies and the formation of immune complexes in tissues, triggering complement activation, inflammation, and irreversible organ damage. SLE can affect any part of the body, resulting in diverse clinical symptoms. One rare manifestation of SLE is lupus mesenteric vasculitis (LMV), which presents with vague symptoms, abnormal laboratory findings, and specific imaging features. LMV, although uncommon, can progress to severe complications such as bowel perforation, haemorrhage, and even mortality. Here, we report a case of LMV with the involvement of multiple organ systems (including mucocutaneous, musculoskeletal, serosal cavities, and haematological systems), presenting initially with life-threatening intractable gastrointestinal bleeding, and complicated by severe pulmonary infection. By sharing this case, we aim to enhance clinicians\' confidence in managing critical SLE cases and raise awareness about disease surveillance.

Before the \"mesorectal\" theory was proposed, the traditional anatomy believed that the \"pelvirectal space\" belonged to the anal canal and perirectal space, which was independent of the rectal structure, located on both sides of the rectum, above the levator ani, and below the peritoneal reflexion, and was composed of a large amount of fatty tissue filling. With the development of the theory of membrane anatomy and the clarification of the concept of \"rectal mesentery\", combined with the author\'s clinical experience, we found that the above-mentioned fat is actually the fat within the mesorectum, as well as the fat tissue of lateral lymph nodes (LLN) such as the internal iliac lymph nodes (No.263) and obturator lymph nodes (No.283) on both sides of the rectal mesentery, rather than the so-called fat tissue within the interstitial space. Therefore, the author believes that the pelvirectal space does not exist. In the anatomical location equivalent to the pelvic rectal space, there is the \"superior levator ani space\" based on the membrane anatomy theory. From the pelvirectal space to the superior levator anal space, it reflects our further understanding of the anatomy of the rectal mesentery.
在提出“直肠系膜”理论之前，传统解剖学认为“骨盆直肠间隙”属肛管、直肠周围间隙，其独立于直肠结构之外，位于直肠两侧的、肛提肌上方的、腹膜反折下方的间隙，由大量脂肪组织填充组成。而随着膜解剖理论的发展、“直肠系膜”概念的明确，结合笔者临床经验，我们发现上述的脂肪其实是直肠系膜内的脂肪，及直肠系膜两侧的髂内淋巴结（No.263）和闭孔淋巴结（No.283）等侧方淋巴结脂肪组织，并不是所谓间隙内的脂肪组织。因此，笔者认为骨盆直肠间隙是不存在的，在相当于骨盆直肠间隙的解剖位置，存在的是基于膜解剖理论的“肛提肌上间隙”。从骨盆直肠间隙到肛提肌上间隙，体现的是我们对于直肠系膜的解剖认识的进一步升华。.

BACKGROUND: Previous studies have established the existence of the mesogastrium, dividing it into 6 sections. The mesogastrium is identified during surgery and used in surgical practice. The aim of the present study was to further investigate its role in gastric cancer prognosis.
METHODS: Between January 2014 and January 2018, patients from the Tongji Hospital were included in this post hoc analysis, including data from a randomized clinical study (DCGC01; http://www.
RESULTS: gov, NCT01978444). Mesogastria containing metastatic lymph nodes were referred to as metastatic mesogastria. Pathology reports were examined to assess metastases in the mesogastrium. Survival was assessed using Kaplan-Meier curves and multivariable Cox models.
RESULTS: Among the 479 patients, 230 (48.0%) had no lymph node metastasis, 34 (7.1%) had 1 metastatic mesogastrium, and 215 (44.9%) had 2 to 6 metastatic mesogastria. Multivariate analysis showed that the number of metastatic mesogastria and N stages were independent risk factors for patient prognosis. In general, a higher metastatic mesogastrium number is positively correlated with a worse prognosis. For identical N stages, 5-year survival rates for patients with 2 to 6 metastatic mesogastria were significantly lower than those for patients with 1 metastatic mesogastrium.
CONCLUSIONS: The number of metastatic mesogastria serves as an independent prognostic factor from the N stage.

UNASSIGNED: Desmoid tumor (DT) is a rare locally aggressive but non-metastatic mesenchymal soft tissue neoplasm that predominantly occurs in the abdominal wall, abdominal cavity, and extremities. Its occurrence in the mesentery is relatively uncommon.
UNASSIGNED: This article reports two cases of desmoid tumor treated at the Department of Gastrointestinal Surgery, Weifang People\'s Hospital. The first case was a 59-year-old male patient who had previously undergone surgery for esophagogastric junction cancer. Postoperatively, he developed an intra-abdominal mass that rapidly increased in size within three months. The second case was a 60-year-old male patient who incidentally discovered a mass in the left lower abdomen. Both patients underwent surgical treatment, and the postoperative pathological diagnosis was mesenteric desmoid tumor.
UNASSIGNED: The treatment of desmoid tumor remains challenging. Simple surgical resection often yields unsatisfactory outcomes, and the efficacy of adjuvant radiotherapy and chemotherapy is also limited. Further research and clinical practice are necessary to improve diagnostic and therapeutic strategies, aiming to enhance patient survival and quality of life.