The Role of the Mesentery in Crohn's Disease: The Contributions of Nerves, Vessels, Lymphatics, and Fat to the Pathogenesis and Disease Course

Quantitative assessment of transmural remission in Crohn's disease using low dose computed tomography (CT) enterography perfusion imaging: a single-centre study based on intestinal microcirculation

AIM

To assess transmural remission in patients with Crohn's disease using low-dose small bowel computed tomography (CT) perfusion scans.

MATERIALS AND METHODS

Forty six patients were divided into active and remission phases based on Crohn's Disease Activity Index (CDAI) and C-reactive protein (CRP). Dual-source CT enterography with low-dose perfusion scans was conducted to generate perfusion parameter maps, including blood flow (BF), blood volume (BV), time to peak (TTP), mean transit time (MTT), and permeability of surface (PS). We compared differences in perfusion parameter values of intestinal walls, mesenteric fat, and lymph nodes between two groups. Receiver operating characteristic (ROC) curves were plotted, and area under the curve (AUC), sensitivity, specificity, and cutoff values were calculated.

RESULTS

The BF, BV, TTP, MTT, and PS values of the intestinal wall were significantly higher in the active phase (P0.05). Additionally, lymph node BF and TTP displayed significant differences (P<0.01).

CONCLUSION

Dual-source CT enterography with low-dose perfusion scans enables quantitative assessment of Crohn's disease microcirculation in intestinal walls, mesenteric fat, and lymph nodes. These quantitative indicators provide strong diagnostic efficacy and offer insights into whether the disease is in transmural remission.

The mesenteric adipokine SFRP5 alleviated intestinal epithelial apoptosis improving barrier dysfunction in Crohn's disease

The hypertrophic mesenteric adipose tissue (htMAT) of Crohn disease (CD) participates in inflammation through the expression of adipokines, but the exact mechanism of this action in the intestine is unknown. Here, we analyzed the expression of secreted frizzled-related protein 5 (SFRP5), an adipokine with cytoprotective effects, in htMAT and its role in CD. The results of this study revealed that the level of SFPR5 increased in the diseased MAT (htMAT) of CD patients and aggregated among intestinal epithelial cells in the diseased intestine and that it could ameliorate intestinal barrier dysfunction in tumor necrosis factor alpha (TNF-α)-stimulated colonic organoids and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced mice at least in part through the inhibition of Wnt5a-mediated apoptosis in epithelial cells. This study elucidates possible mechanisms by which mesenteric adipokines influence the progression of enteritis and provides a new theoretical basis for the treatment of CD via the mesenteric pathway.

Extracellular vesicles derived from creeping fat stem cells promote lymphatic function and restrain inflammation of Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory disease in the intestinal tract. Mesenteric fat wrapping and thickening, or creeping fat (CrF), is a typical characteristic of CD and it involves lymphangiogenesis and altered lymphatic function. By releasing extracellular vesicles (EVs), adipose tissue-derived stem cells (ADSCs) can regulate their adjacent cells. However, the regulating roles of ADSC-EVs in CrF (CrF-EVs) in CD, especially in modulating lymphatic function and mitigating the progression of mesenteritis and colitis, remains elusive.

METHODS

To evaluate the regulative roles of CrF-EVs on lymphatic functions, in vitro assays were performed using human lymphatic endothelial cells (HLECs). Next, Interleukin 10 knock-out (Il-10-/-) mice were used to assess the biological functions of CrF-EVs in spontaneous mesenteritis and colitis. Moreover, tissue and serum from various cohorts of CD patients were used to determine the prognostic value of miR-132-3p.

RESULTS

CrF-EVs significantly attenuated spontaneous mesenteritis and colitis in Il-10-/- mice via promoting lymphangiogenesis and lymphatic drainage. Using high-throughput sequencing, we demonstrated that CrF-EVs significantly increased HLEC proliferation, migration, tube formation and CCL-21 production in a miR-132-3p/RASA1/ERK1/2 axis-dependent manner. Accordingly, upregulated miR-132-3p was observed in patient CrF, positively correlated with lymphangiogenesis while negatively correlated with inflammatory factors (tumour necrosis factor-α and IL-6) level. Moreover, serum miR-132-3p demonstrated a positive correlation with disease activity.

CONCLUSIONS

EVs derived from CrF ADSCs, containing elevated levels of miR-132-3p, could promote lymphatic function and restrain inflammation of CD. Our results provide a novel insight into the role of mesenteric lymphatics in CD progression and reveal a new potential therapeutic.

KEY POINTS

Extracellular vesicles (EVs) of creeping fat (CrF) derived adipose stem cells effectively attenuate chronic mesenteritis and colitis in Crohn's disease (CD). The lymphatic vessels play an important role in disease development of CD and their functions are improved by CrF-EV-miR-132-3p through RASA1/ERK1/2 signaling. MiR-132-3p expression is upregulated in CrF and serum of CD patients, and tightly linked with inflammation and disease activity.

Effect of mesenteric sparing or extended resection in primary ileocolic resection for Crohn's disease on postoperative endoscopic recurrence (SPICY): an international, randomised controlled trial

BACKGROUND

Retrospective research suggests that excision of the affected mesentery can improve outcomes after an ileocoecal resection in Crohn's disease. However, prospective data from randomised controlled trials are scarce. We aimed to compare rates of postoperative recurrence in patients with Crohn's disease who underwent extended mesenteric resection.

METHODS

This international, randomised controlled trial was done in six hospitals and tertiary care centres in the Netherlands and Italy. Eligible patients were aged 16 years or older and had Crohn's disease that was previously confirmed by endoscopy in the terminal ileum or ileocolic region (L1 or L3 disease), with an imaging update in the past 3 months (ultrasound, MRI, or CT enterography). Eligible patients were scheduled to undergo primary ileocolic resection with ileocolic anastomosis. Enrolled patients were assigned by use of simple random allocation (1:1) to either extended mesenteric resection (intervention) or conventional mesenteric sparing resection (control). The primary endpoint was endoscopic recurrence 6 months after surgery. Analyses were done in all patients with primary endpoint data, excluding those who had no anastomosis, a postoperative diagnosis other than Crohn's disease, or withdrew consent. This trial was registered with ClinicalTrials.gov, NCT04538638.

FINDINGS

Between Feb 19, 2020, and April 24, 2023, we assessed 217 patients for eligibility. 78 patients were excluded due to failure to meet the inclusion criteria or refusal to participate. 139 patients were enrolled and randomly assigned to either extended mesenteric resection (n=71) or mesenteric sparing resection (n=68). All 139 patients underwent surgery. Six patients were excluded after random assignment due to withdrawal of consent (n=2), postoperative diagnosis other than Crohn's disease (n=2) and no anastomosis performed (in case of a stoma; n=2). Two patients were lost to follow-up, and two more patients deviated from the protocol by undergoing investigations other than endoscopy 6 months after. 133 patients were included in the baseline analysis (67 in the extended resection group and 66 in the sparing resection group) of whom 57 (43%) were male. Baseline characteristics were similar between the groups, and median patient age was 36 years (IQR 25-54). 131 patients were analysed for the primary outcome. There was no difference between groups in the rate of endoscopic recurrence at 6 months after surgery (28 [42%] of 66 patients in the extended mesenteric resection group vs 28 [43%] of 65 patients in the mesenteric sparing resection group, relative risk 0·985, 95% CI 0·663-1·464; p=1·0). Five (8%) of 66 patients in the extended mesenteric resection group had anastomotic leakage within the 30 days after surgery, as did one (2%) of 65 in the mesenteric sparing group. Postoperative complications of Clavien-Dindo grade IIIa or higher were reported in seven (11%) patients in the mesenteric resection group and five (8%) in the mesenteric sparing group.

INTERPRETATION

Extended mesenteric resection was not superior to conventional resection with regard to endoscopic Crohn's disease recurrence. These data support the guideline-recommended mesenteric sparing approach.

FUNDING

Topconsortia voor Kennis en Innovatie-Topsector Life Sciences & Health.

Inhibition of Transmural Inflammation in Crohn's Disease by Orally Administered Tumor Necrosis Factor-Alpha Deoxyribozymes-Loaded Pyroptosis Nanoinhibitors

Crohn's disease (CD) is a refractory chronic inflammatory bowel disease (IBD) with unknown etiology. Transmural inflammation, involving the intestine and mesentery, represents a characteristic pathological feature of CD and serves as a critical contributor to its intractability. Here, this study describes an oral pyroptosis nanoinhibitor loaded with tumor necrosis factor-α (TNF-α) deoxyribozymes (DNAzymes) (DNAzymes@degradable silicon nanoparticles@Mannose, Dz@MDSN), which can target macrophages at the site of inflammation and respond to reactive oxygen species (ROS) to release drugs. Dz@MDSN can not only break the inflammatory cycle in macrophages by degrading TNF-α mRNA but also reduce the production of ROS mainly from macrophages. Moreover, Dz@MDSN inhibits excessive pyroptosis in epithelial cells through ROS clearance, thereby repairing the intestinal barrier and reducing the translocation of intestinal bacteria to the mesentery. Consequently, these combined actions synergistically contribute to the suppression of inflammation within both the intestine and the mesentery. This study likely represents the first successful attempt in the field of utilizing nanomaterials to achieve transmural healing for CD, which also provides a promising treatment strategy for CD patients.

Infliximab modifies CD74-mediated lymphatic abnormalities and adipose tissue alterations in creeping fat of Crohn's disease

BACKGROUND

Lymphatic abnormalities are essential for pathophysiologic changes of creeping fat (CrF) in Crohn's disease (CD). Anti-tumor necrosis factor (TNF) therapy has been proved to alleviate CrF lesions, however, whether it achieves these by remodeling lymphatics is unknown.

METHODS

CD74 expression was detected in CrF and uninvolved mesentery of CD patients. Lymphatic functions in vitro were evaluated and lymphatic endothelium barrier were checked by transendothelial electrical resistance (TEER) and FITC-Dextran permeability. Protein level of tight junction and signaling pathways were detected by western blotting.

RESULTS

CD74 was upregulated in LECs of CrF and positively correlated with TNF-α synthesis. This was suppressed by IFX administration. In vitro, TNF-α stimulated LECs to express CD74 through NF-κB signaling pathway, and this was rescued by IFX. CD74 downregulation suppressed the abilities of LECs in proliferation, migration and tube formation. Interaction of CD74-MIF impaired LECs' barrier via reducing tight junction proteins in an ERK1/2-dependent manner, which was reversed by CD74 downregulation. Consistently, the CD patients receiving IFX therapy displayed decreased lymphangiogenesis and improved mesenteric lymphatic endothelium barrier, companied with reduced adipocyte size and adipokine levels in CrF.

CONCLUSIONS

Anti-TNF therapy could modify pathological changes in CrF by alleviating CD74-mediated lymphatic abnormalities.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BACKGROUND

Visceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway.

METHODS

Thirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis.

RESULTS

Compared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP.

CONCLUSIONS

In SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

Pre-operative visceral adipose tissue radiodensity is a potentially novel prognostic biomarker for early endoscopic post-operative recurrence in Crohn's disease

BACKGROUND

Evidence suggests inflammatory mesenteric fat is involved in post-operative recurrence (POR) of Crohn's disease (CD). However, its prognostic value is uncertain, in part, due to difficulties studying it non-invasively.

AIM

To evaluate the prognostic value of pre-operative radiographic mesenteric parameters for early endoscopic POR (ePOR).

METHODS

We conducted a retrospective cohort study of CD subjects ≥ 12 years who underwent ileocecal or small bowel resection between 1/1/2007 to 12/31/2021 with computerized tomography abdomen/pelvis ≤ 6 months pre-operatively and underwent ileocolonoscopy ≤ 15 months post-operatively. Visceral adipose tissue (VAT) volume (cm3), ratio of VAT:subcutaneous adipose tissue (SAT) volume, VAT radiodensity, and ratio of VAT:SAT radiodensity were generated semiautomatically. Mesenteric lymphadenopathy (LAD, largest lymph node > 10 mm) and severe vasa recta (VR) engorgement (diameter of the VR supplying diseased bowel ≥ 2 × VR supplying healthy bowel) were derived manually. The primary outcome was early ePOR (Rutgeert's score ≥ i2 on first endoscopy ≤ 15 months post-operatively) and the secondary outcome was ePOR severity (Rutgeert's score i0-4). Regression analyses were performed adjusting for demographic and disease-related characteristics to calculate adjusted odds ratio (aOR) and 95% confidence interval (CI).

RESULTS

Of the 139 subjects included, 45% of subjects developed early ePOR (n = 63). VAT radiodensity (aOR 0.59, 95%CI: 0.38-0.90) and VAT:SAT radiodensity (aOR 8.54, 95%CI: 1.48-49.28) were associated with early ePOR, whereas, VAT volume (aOR 1.23, 95%CI: 0.78-1.95), VAT:SAT volume (aOR 0.80, 95%CI: 0.53-1.20), severe VR engorgement (aOR 1.53, 95%CI: 0.64-3.66), and mesenteric LAD (aOR 1.59, 95%CI: 0.67-3.79) were not. Similar results were observed for severity of ePOR.

CONCLUSION

VAT radiodensity is potentially a novel non-invasive prognostic imaging marker to help risk stratify CD patients for POR.

CT energy spectral parameters of creeping fat in Crohn's disease and correlation with inflammatory activity

OBJECTIVES

Creeping fat is a kind of unique abnormal mesenteric tissue at the sites of diseased bowel of Crohn's disease. By using dual-energy CT enterography, this study aimed to evaluate the feasibility of spectral parameters in the quantitative analysis of mesenteric adipose tissue or creeping fat.

METHODS

In this study, patients with known or suspected Crohn's disease who underwent dual-energy CT enterography from March 1, 2019, to March 31, 2021, were enrolled. Among them, 40 patients with surgery and pathology-proven creeping fat were selected as the creeping fat Crohn's disease group, and 40 normal patients were selected as the control group. The quantitative spectral parameters including the slope of the Hounsfield unit curve, normalised fat-water concentration, normalised fat-iodine concentration, and normalised fat volume fraction at the enteric phases were obtained. Mann-Whitney U test, Kruskal-Wallis H test, and receiver operating characteristic curve analysis were applied to compare quantitative parameters among various groups.

RESULTS

A significant difference was observed in the slope of the Hounsfield unit curve, normalised fat-water concentration, normalised fat-iodine concentration, and normalised fat volume fraction between mesenteric adipose tissue and creeping fat with Crohn's disease at the enteric phase (all p < 0.001). The slope of the Hounsfield unit curve of creeping fat at the enteric phase had a better capability to distinguish inactive and active Crohn's disease (AUC = 0.93, p < 0.001).

CONCLUSION

Dual-energy CT enterography with quantitative spectral parameters is a potentially novel noninvasive tool for evaluating creeping fat in Crohn's disease.

CRITICAL RELEVANCE STATEMENT

Energy spectral parameters of creeping fat in Crohn's disease are significantly different from normal mesenteric adipose tissues and are correlated with inflammatory activity.

KEY POINTS

• Dual-energy CT enterography allows quantitatively assessing creeping fat with spectral parameters. • The creeping fat has distinct spectral parameters to normal mesenteric adipose. • The spectral parameters accurately differentiate active and inactive Crohn's disease.

Creeping fat exhibits distinct Inflammation-specific adipogenic preadipocytes in Crohn's disease

Creeping fat (CrF) is an extraintestinal manifestation observed in patients with Crohn's disease (CD). It is characterized by the accumulation of mesenteric adipose tissue (MAT) that wraps around the intestinal wall. Although the role of CrF in CD is still debated, multiple studies have highlighted a correlation between CrF and inflammation, as well as fibrostenosais of the intestine, which contributes to the worsening of CD symptoms. However, the mechanism underlying the potential role of CrF in the development of Crohn's fibrosis remains an enigma. This study aimed to analyze CrF comprehensively using single-cell RNA sequencing analysis. The data was compared with transcriptomic data from adipose tissue in other disease conditions, such as ulcerative colitis, lymphedema, and obesity. Our analysis classified two lineages of preadipocyte (PAC) clusters responsible for adipogenesis and fibrosis in CrF. Committed PACs in CrF showed increased cytokine expression in response to bacterial stimuli, potentially worsening inflammation in patients with CD. We also observed an increase in fibrotic activity in PAC clusters in CrF. Co-analyzing the data from patients with lymphedema, we found that pro-fibrotic PACs featured upregulated pentraxin-3 expression, suggesting a potential target for the treatment of fibrosis in CrF. Furthermore, PACs in CrF exhibited a distinct increase in cell-to-cell communication via cytokines related to inflammation and fibrosis, such as CCL, LIGHT, PDGF, MIF, and SEMA3. Interestingly, these interactions also increased in PACs of the lymphedema, whereas the increased MIF signal of PACs was found to be a distinct characteristic of CrF. In immune cell clusters in CrF, we observed high immune activity of pro-inflammatory macrophages, antigen-presenting macrophages, B cells, and IgG+ plasma cells. Finally, we have demonstrated elevated IgG+ plasma cell infiltration and increased pentraxin-3 protein levels in the fibrotic regions of CrF in CD patients when compared to MAT from both UC patients and healthy individuals. These findings provide new insights into the transcriptomic features related to the inflammation of cells in CrF and suggest potential targets for attenuating fibrosis in CD.

Extended versus limited mesenteric excision for operative Crohn's disease: 30-Day outcomes from the ACS-NSQIP database

PURPOSE

Recent studies have suggested that extended mesenteric excision (ME) may reduce surgical reintervention in Crohn's Disease (CD), but there remains clinical concerns regarding potential peri-operative morbidity. This retrospective study compares 30-day perioperative morbidity between limited and extended ME in segmental colectomies for CD.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement (ACS-NSQIP) colectomy-specific database, all patients with CD undergoing segmental colectomy for non-malignant indications between 2014-2019 were included. A lymph node harvest of 12 or more nodes was used as a surrogate for extended ME. The primary outcome was NSQIP major morbidity. Secondary outcomes included abdominal complications and perioperative bleeding.

RESULTS

Of 3,709 patients included from the ACS-NSQIP database, 3,087 underwent limited ME and 622 underwent extended ME. On univariate analysis, those with limited mesenteric excision were less likely to be anemic (46.1% vs 55.0%, p < 0.001) and have undergone an open surgery (44.7% vs 34.7%, p < 0.001). On univariate comparison of limited and extended ME, there was no significant difference in major morbidity. On multiple logistic regression, controlling for age, sex, BMI, smoking, preoperative sepsis, preoperative anemia, surgical approach, emergency surgery, stoma creation, bowel preparation, and immunosuppression, the extent of ME was not an independent predictor of NSQIP major morbidity (OR 1.1, 95% CI 0.84-1.44). Likewise, the extent of ME was not associated with an increase in abdominal complications (OR 0.95, 95% CI 0.76-1.19) or post-operative bleeding (OR 1.89, 95% CI 0.75-1.53).

CONCLUSION

Extended ME for CD was not associated with an increase in 30-day perioperative major morbidity.

Results of the Eighth Scientific Workshop of ECCO: Pathophysiology and Risk Factors of Postoperative Crohn's Disease Recurrence after an Ileocolonic Resection

Postoperative recurrence [POR] after an ileocolonic resection with ileocolonic anastomosis is frequently encountered in patients with Crohn's disease. The 8th Scientific Workshop of ECCO reviewed the available evidence on the pathophysiology and risk factors for POR. In this paper, we discuss published data on the role of the microbiome, the mesentery, the immune system and the genetic background. In addition to investigating the causative mechanisms of POR, identification of risk factors is essential to tailor preventive strategies. Potential clinical, surgical and histological risk factors are presented along with their limitations. Emphasis is placed on unanswered research questions, guiding prevention of POR based on individual patient profiles.

Mathematical Models Including microRNA Levels of Mesenteric Adipose Tissue May Predict Postoperative Relapse in Crohn's Disease Patients

Background and Aims

Recent evidence suggests that the mesenteric adipose tissue (MAT) near the affected intestine may play a role in Crohn's disease (CD) pathophysiology. Modulation of several transcripts has already been identified in the MAT of CD in the literature. Therefore, our aim was to validate the microRNA (miRNA) transcript levels and their target genes in the MAT of active CD patients and correlate them with clinical and epidemiological data.

Methods

Samples from the MAT of surgical specimens from 25 active CD patients were obtained. The control group comprised fifteen patients who underwent surgery for other diseases, except inflammatory bowel diseases. Transcriptional levels of miRNA and their target genes were assessed by quantitative real-time polymerase chain reaction. The correlation between transcripts and clinical characteristics was obtained using multiple linear regression. The mathematical models (M) underwent a statistical filter to ensure robustness and reliability (P value < .05; adjusted R-squared (Rˆ2)> .99; correct predictions of more than 60%).

Results

miRNA-650 and miRNA-29c were upregulated in the MAT of CD compared to the control group (P < .0001 and P = .0032, respectively), besides presenting decreased levels of their target genes. Two were target genes of the miRNA-650: glutamine-fructose-6-phosphate transaminase 2 (P = .012) and aldehyde dehydrogenase 4 family (P = .0035); and 4 were targets of the miRNA-29c: cell death-inducing DFFA-like effector c (P = .001), E2F transcription factor-1 (P = .007), hypoxia-inducible factor 3 subunit alpha (P = .0029), and pyruvate dehydrogenase kinase 4 (P = .0054). We found 2 M with statistical strength and robustness. The performance test identified one model with 100% accuracy for predicting the month of recurrence and determining patients with less risk of early relapse after surgery.

Conclusion

We demonstrate that miRNA-650 and miRNA-29c and some of their target genes, besides clinical and epidemiological variables, may be useful in a model to predict when disease relapse may occur in CD patients who underwent surgery. These findings constitute a potential tool to guide postoperative clinical management.

Inflammation and Digestive Cancer

Chronic inflammation is linked to carcinogenesis, particularly in the digestive organs, i.e., the stomach, colon, and liver. The mechanism of this effect has, however, only partly been focused on. In this review, we focus on different forms of chronic hepatitis, chronic inflammatory bowel disease, and chronic gastritis, conditions predisposing individuals to the development of malignancy. Chronic inflammation may cause malignancy because (1) the cause of the chronic inflammation is itself genotoxic, (2) substances released from the inflammatory cells may be genotoxic, (3) the cell death induced by the inflammation induces a compensatory increase in proliferation with an inherent risk of mutation, (4) changes in cell composition due to inflammation may modify function, resulting in hormonal disturbances affecting cellular proliferation. The present review focuses on chronic gastritis (Helicobacter pylori or autoimmune type) since all four mechanisms may be relevant to this condition. Genotoxicity due to the hepatitis B virus is an important factor in hepatocellular cancer and viral infection can similarly be central in the etiology and malignancy of inflammatory bowel diseases. Helicobacter pylori (H. pylori) is the dominating cause of chronic gastritis and has not been shown to be genotoxic, so its carcinogenic effect is most probably due to the induction of atrophic oxyntic gastritis leading to hypergastrinemia.

Creeping Fat in Crohn's Disease-Surgical, Histological, and Radiological Approaches

During the course of Crohn's disease, the response of mesenteric adipose tissue to the production of inflammatory mediators and bacterial invasion through the intestinal mucosa results in the formation of creeping fat. Creeping fat describes the arresting finger-like projections that surround the inflamed bowel. In this review, the microscopic and macroscopic features of creeping fat and histological evidence for the importance of this tissue are discussed. Moreover, the most recent insights into the radiological assessment of creeping fat in patients with Crohn's disease are reported. Advances in imaging techniques have revolutionized the possibility of visualization and quantification of adipose tissue depots with excellent accuracy. Visceral fat has been significantly correlated with various Crohn's-disease-related outcomes. Despite the difficulties in distinguishing physiologic perienteric fat from creeping fat, the growing interest in fat-wrapping in Crohn's disease has rejuvenated radiologic research. With regard to the noninvasive fat-wrapping assessment, a novel CT enterography-based mesenteric creeping fat index has been developed for the mitigation of the confounding effect of normal retroperitoneal and perienteric adipose tissue. Research on machine learning algorithms and computational radiomics in conjunction with mechanistic studies may be the key for the elucidation of the complex role of creeping fat in Crohn's disease.

Characterization of prokineticin system in Crohn's disease pathophysiology and pain, and its modulation by alcohol abuse: A preclinical study

BACKGROUND

Crohn's disease-(CD) pathogenesis is still unknown and chronic pain is a frequent symptom in CD-patients. Identifying novel therapeutic targets and predisposing factors is a primary goal. In this regard, prokineticin system-(PKS) appears a promising target.

AIMS AND METHODS

TNBS-model was used. DAI, abdominal and visceral pain, and muscle strength were monitored. CD-mice were sacrificed at two times (day 7 and 14 after TNBS) in order to identify PKS involvement in CD pathophysiology and pain. PKS characterization was performed in mesenteric lymph nodes-(MLN), colon, myenteric plexus-(MP), dorsal root ganglia-(DRGs) and spinal cord-(SC). Inflammation/neuroinflammation was also assessed in the same tissues. In order to evaluate alcohol abuse as a possible trigger for CD and its effect on PKS activation, naïve mice were administered (oral-gavage) with ethanol for 10 consecutive days. PKS as well as inflammation/neuroinflammation were evaluated in MLN, colon and MP.

RESULTS

TNBS treated-mice showed a rapid increase in DAI, abdominal/visceral hypersensitivity and a progressive strength loss. In all tissue analysed of CD-mice, a quick and significant increase of mRNA of PKs and PKRs was observed, associated with an increase of pro-inflammatory cytokines (IL-1β, IL-6 and TNFα) and macrophage/glia markers (iba1, CD11b and GFAP) levels. In alcohol abuse model, ethanol induced in colon and MP a significant PKS activation accompanied by inflammation/neuroinflammation.

CONCLUSIONS

We can assume that PKS may be involved in CD development and pain. Furthermore, alcohol appears to activate PKS and may be a trigger factor for CD.

Effects of visceral adipose tissue on anti-tumour necrosis factor-α in Crohn's disease

Background

It remains unclear whether visceral adipose tissue (VAT) can predict the response of patients with Crohn's disease (CD) to anti-tumour necrosis factor-α (anti-TNF-α) therapy.

Objectives

This study aimed to investigate whether VAT predicts the efficacy of infliximab (IFX) for different sites of CD and its relationship with serum TNF-α levels and IFX serum trough concentration.

Design

This is a multicentre retrospective study.

Methods

Patients with CD treated with IFX from January 2014 to January 2021 were included. The perimeter of the visceral adipose area was obtained by a Computed Tomography (CT) scan. Participants were classified according to the lesion site (L1, L2, and L3) and visceral fat area. The participants were divided into colon-uninvolved non-visceral obesity (L1-VATL), colon-uninvolved visceral obesity (L1-VATH), colon-involved non-visceral obesity (L2 + L3-VATL), and colon involved visceral obesity (L2 + L3-VATH) groups. The end points of this study were set as disease remission status at 6 and 12 months.

Results

The final cohort included 140 patients. Regarding efficacy at 6 and 12 months, there was a significant difference between L1-VATL (73.8% versus 36.8%, p = 0.006) and L1-VATH (81.0% versus 47.4%, p = 0.008) groups. In the analysis of serum TNF-α levels and IFX serum trough concentrations, there was a significant difference between L1-VATL and L1-VATH (59.5 pg/mL versus 236.0 pg/mL, pTNF-α = 0.006), (10.0 μg/mL versus 0.4 μg/mL, pIFX = 0.000), and L1-VATH and L2 + L3-VATH (78.7 pg/mL versus 118.6 pg/mL, pTNF-α = 0.031), (0.4 μg/mL versus 6.40 μg/mL, pIFX = 0.017).

Conclusion

In L1 patients, the VAT level predicted the efficacy of IFX, with high VAT values indicating poor efficacy. The VAT level may be a useful radiological marker to predict the efficacy of IFX in patients with various types of CD.

Inflammation of Mesenteric Adipose Tissue Correlates with Intestinal Injury and Disease Severity in Rats with Severe Acute Pancreatitis

BACKGROUND

Visceral adipose tissue (VAT) is related to SAP prognosis. As a depot of VAT, mesenteric adipose tissue (MAT) resides between pancreas and gut, which might affect SAP and the secondary intestinal injury.

AIMS

To investigate the changes of MAT in SAP.

METHODS

24 SD rats were randomly divided into four groups. 18 rats in SAP group were euthanized in time gradients (6 h, 24 h, and 48 h after modeling) and the others in control group. Blood samples and tissues of pancreas, gut, and MAT were taken for analysis.

RESULTS

Compared to the control group, SAP rats appeared MAT inflammation, presenting higher mRNA expression of TNF-α and IL-6 and lower IL-10, and histological changes after 6 h of modeling, which became worse over time. Flow cytometry showed that B lymphocytes increased in MAT after 24 h of SAP modeling and lasted up to 48 h, earlier than the changes of T lymphocytes and macrophages. The intestinal barrier integrity was damaged after 6 h of modeling, presenting lower mRNA and protein expression of ZO-1 and occludin, higher serum levels of LPS and DAO, with pathological changes, which gradually aggravated after 24 h and 48 h. SAP rats had higher serum levels of inflammatory indicators and revealed histological inflammation of pancreas, the severity of which increased with the passage of modeling time.

CONCLUSION

MAT appeared inflammation in early-stage SAP, and became worse over time, with the same trend as the intestinal barrier injury and the severity of pancreatitis. B lymphocytes infiltrated early in MAT, which might promote the MAT inflammation.

Medical and Surgical Implications of Mesenteric Adipose Tissue in Crohn's Disease: A Review of the Literature

Mesenteric adipose tissue (MAT) has gained substantial attention as an active player in Crohn's disease (CD), but its clinical significance is poorly understood and likely reflects, in part, difficulties assessing MAT noninvasively. Recent radiologic studies have identified candidate surrogate markers that may reflect inflammatory alterations of MAT in CD and have found that certain features including visceral adipose tissue may inform risk of complicated disease behavior, risk for surgery, and postoperative outcomes. Additionally, emerging surgical data have suggested MAT may even be a therapeutic target to mitigate postoperative recurrence of CD. However, the current studies have variable results, reduced sample sizes, and methodological limitations that preclude incorporating the radiologic and surgical findings into clinical practice. Nonetheless, the results are promising and potentially have important implications for the medical and surgical management of CD, which merits that additional studies are warranted. Thus, we have reviewed the available literature on the medical and surgical implications of MAT in CD to summarize our current understanding and identify gaps in knowledge to inform future investigations.

Perioperative optimization of Crohn's disease

Crohn's disease (CD) is a chronic inflammatory disease mainly affecting the gastrointestinal tract. With the increased availability of modalities in the last two decades, the treatment of CD has advanced remarkably. Although medical treatment is the mainstay of therapy, most patients require surgery during the course of their illness, especially those who experience complications. Nutritional optimization and ERAS implementation are crucial for patients with CD who require surgical intervention to reduce postoperative complications. The increased surgical risk was found to be associated with the use of corticosteroids, but the association of surgical risk with immunomodulators, biologic therapy, such as anti-TNF mediations, anti-integrin medications, and anti-IL 12/23 was low in certainty. Decisions about preoperative medication must be made on an individual case-dependent basis. Preoperative imaging studies can assist in the planning of appropriate surgical strategies and approaches. However, patients must be informed of any alterations to their treatment. In summary, the management of perioperative medications and surgery-related decision-making should be individualized and patient-centered based on a multidisciplinary approach.

Aberrant Mesenteric Adipose Extracellular Matrix Remodelling is Involved in Adipocyte Dysfunction in Crohn's Disease: The Role of TLR-4-mediated Macrophages

BACKGROUND AND AIMS

Hypertrophic mesenteric adipose tissue [htMAT] is involved in the disease progression of Crohn's disease [CD] through expressing proinflammatory adipokines from dysfunctional adipocytes by unknown mechanism. Adipocyte function is affected by dynamic adipose tissue extracellular matrix [ECM] remodelling that is mainly mediated by macrophages, and our study aimed to reveal whether aberrant ECM remodelling was present in CD-htMAT and its effects on adipocyte dysfunction, as well as the mechanism.

METHODS

ECM remodelling was examined in MAT samples from CD patients and controls. Mice with dinitrobenzene sulphonic acid [DNBS]-induced colitis were used in vivo study, and lipopolysaccharide [LPS]-induced remodelling behaviour in macrophages was examined in vitro. Macrophages or TLR4 inhibition were used to analyse ECM remodelling mechanisms and their effects on adipocyte function.

RESULTS

Aberrant ECM remodelling: was observed in CD-htMAT, which was characterised by a widened and deformed ECM structure accompanied by dysregulated matrix synthesis and degradation; served as a reservoir for inflammatory factors/cells dominated by macrophages; and was involved in adipocyte dysfunction. In addition, macrophages were the main source of ECM remodelling regulatory factors with activation of Toll-like receptor 4 [TLR4] in htMAT. In vivo, macrophage depletion or TLR4 inhibition largely attenuated mesenteric ECM remodelling while improving mesenteric adipocyte dysfunction during chronic enteritis. In vitro, antagonizing TLR4 significantly inhibited LPS-induced macrophage ECM remodelling behavior.

CONCLUSIONS

The aberrant ECM remodelling in CD-htMAT contributed to mesenteric adipocyte dysfunction, which may be caused at least partly by TLR4-mediated macrophage remodelling behavior. Inhibiting ECM remodelling may be a potential therapeutic strategy for CD.

Serial Changes in Body Composition and the Association with Disease Activity during Treatment in Patients with Crohn's Disease

Objectives: To analyze serial changes in body composition and investigate the association between body composition changes and disease activity changes in patients with Crohn’s disease (CD). Methods: Seventy-one patients with CD who had been treated and followed-up at our institution were included. Two to four computed tomography images were acquired at baseline, and the 2−5-year, 5−8-year, and last follow-ups were selected per patient for body composition and disease activity analyses. Visceral fat area (VFA), skeletal muscle index (SMI; skeletal muscle area/height2), and subcutaneous fat area (SFA) were assessed using an artificial-intelligence-driven fully automated method. Disease activity was assessed using a modified computed tomography scoring system and the Simple Endoscopic Score for Crohn’s Disease. The associations between body composition, disease activity, and remission were investigated. Results: The mean age was 29.83 ± 11.27 years; most patients were men (48/71, 67.6%); and the median follow-up was 144 (12−264) months. Overall, VFA and SFA gradually increased, while SMI decreased during the follow-up. Sarcopenia was associated with the female sex, higher disease activities at baseline (p = 0.01) and the last follow-up (p = 0.001). SMI and SFA inversely correlated with the disease activity, i.e., the more severe the disease activity, the lower the SMI and SFA (p < 0.05). SMI at the last follow-up was the only significant predictor of remission (OR = 1.21, 95% confidence interval: 1.03−1.42, p = 0.021). Conclusion: SMI decreased while VFA and SFA increased during the treatment follow-up in patients with CD. Sarcopenia was associated with higher disease activity, and SMI and SFA inversely correlated with disease activity. SMI at the last follow-up was the significant factor for remission.

Pathogenesis of Fistulating Crohn's Disease: A Review

Sustained, transmural inflammation of the bowel wall may result in the development of a fistula in Crohn's disease (CD). Fistula formation is a recognized complication and cause of morbidity, occurring in 40% of patients with CD. Despite advanced treatment, one-third of patients experience recurrent fistulae. Development of targeting treatment for fistulae will be dependent on a more in depth understanding of its pathogenesis. Presently, pathogenesis of CD-associated fistulae remains poorly defined, in part due to the lack of accepted in vitro tissue models recapitulating the pathogenic cellular lesions linked to fistulae and limited in vivo models. This review provides a synthesis of the existing knowledge of the histopathological, immune, cellular, genetic, and microbial contributions to the pathogenesis of CD-associated fistulae including the widely accredited contribution of epithelial-to-mesenchymal transition, upregulation of matrix metalloproteinases, and overexpression of invasive molecules, resulting in tissue remodeling and subsequent fistula formation. We conclude by exploring how we might utilize advancing technologies to verify and broaden our current understanding while exploring novel causal pathways to provide further inroads to future therapeutic targets.

Impact of Obesity on the Course of Management of Inflammatory Bowel Disease—A Review

It is already well-known that visceral adipose tissue is inseparably related to the pathogenesis, activity, and general outcome of inflammatory bowel disease (IBD). We are getting closer and closer to the molecular background of this loop, finding certain relationships between activated mesenteric tissue and inflammation within the lumen of the gastrointestinal tract. Recently, relatively new data have been uncovered, indicating a direct impact of body fat on the pattern of pharmacological treatment in the course of IBD. On the other hand, ileal and colonic types of Crohn’s disease and ulcerative colitis appear to be more diversified than it was thought in the past. However, the question arises whether at this stage we are able to translate this knowledge into the practical management of IBD patients or we are still exploring the scientific background of this pathology, having no specific tools to be used directly in patients. Our review explores IBD in the context of obesity and associated disorders, focusing on adipokines, creeping fat, and possible relationships between these disorders and the treatment of IBD patients.

Mesenteric Adipose Tissue Contributes to Intestinal Fibrosis in Crohn's Disease Through the ATX-LPA Axis

BACKGROUND AND AIMS

Intestinal fibrostenosis is an important cause of surgical intervention in patients with Crohn's disease [CD]. Hypertrophic mesenteric adipose tissue [MAT] is associated with the disease process of CD. The purpose of this study was to investigate the contribution of MAT to intestinal fibrosis.

METHODS

MAT from surgical specimens of fibrostenotic CD patients and controls was collected for measurement of the levels of autotaxin [ATX] and lysophosphatidic acid [LPA]. ATX was inhibited in vivo in DNBS [dinitrobenzene sulfonic acid]-induced colitis mice, which were evaluated for colonic inflammation and fibrosis. 3T3-L1 cells and primary colonic fibroblasts were used in vitro to investigate the interaction between MAT and intestinal fibrosis, as well as the molecular mechanism underlying this interaction.

RESULTS

MAT adjacent to the fibrostenotic intestine in CD patients showed an activated ATX-LPA axis. An in vivo study indicated that inhibition of ATX was associated with the improvement of morphology and function of diseased MAT, which was combined with ameliorated intestinal inflammation and fibrosis in DNBS-instilled mice. In vitro studies showed that hypoxia stimulated adipocyte ATX expression and that LPA stabilized adipocyte HIF-1α protein, forming an ATX-LPA-HIF-1α amplification loop and aggravating adipocyte dysfunction. LPA secreted by adipocytes bound to LPA1 on the surface of fibroblasts, promoted their proliferation and differentiation, and increased the expression of fibrosis-related factors.

CONCLUSIONS

The ATX-LPA axis regulated intestinal fibrosis by influencing the proliferation and differentiation of intestinal fibroblasts. Inhibiting this axis may be a therapeutic target for intestinal fibrosis in CD.

Can visceral adipose tissue and skeletal muscle predict recurrence of newly diagnosed Crohn's disease in different treatments

BACKGROUND AND AIMS

It is crucial to manage the recurrence of Crohn's disease (CD). This study is aimed to explore whether visceral adipose tissue (VAT) and skeletal muscle (SM) are associated with the recurrence of CD upon different treatments.

METHODS

All patients with a definite diagnosis of CD were retrospectively divided into three groups according to distinct treatment regimens: 5-amino salicylic acid group (Group A), steroids + azathioprine (Group B) and biologics (Group C). The pretreatment computerized tomography (CT) images and clinical data were collected. The VAT area, mesenteric fat index (MFI), the ratio of VAT area to fat mass (VAT area/FM) were assessed. The primary end point was the recurrence of CD within 1 year of follow-up.

RESULTS

A total of 171 CD patients were enrolled, including 57 (33.33%) patients in Group A, 70 (40.94%) patients in Group B and 44 (25.73%) patients in Group C. Patients with 1-year recurrence had higher MFI (P = 0.011) and VAT area/FM (P = 0.000). ROC curve demonstrated that patients with the ratio of VAT area/FM and MFI higher than 0.578 and 1.394 tended to have recurrence with the AUC of 0.707 and 0.709. Similar results could be observed in Group A & B but not in Group C.

CONCLUSIONS

High VAT area/FM and MFI are related to recurrence within 1 year for newly diagnosed CD patients treated by 5-amino salicylic or azathioprine + steroids rather than biologics. We could not observe any radiological data associated with the recurrence of CD patients under biological treatment.

Symptomatic ileocolic pseudoaneurysm following laparoscopic ileocecectomy for Crohn's disease: A case report

INTRODUCTION

Crohn's disease is prevalent worldwide. It is an idiopathic, chronic and relapsing disease, characterized by chronic inflammation of any part of the gastrointestinal tract. Vascular involvement rarely occurs in Crohn's patients. However, the chronic inflammatory process leads to structural and functional changes in the vascular endothelium. We present a case of ileocolic artery pseudoaneurysm after laparoscopic ileocecectomy in a Crohn's patient.

CASE PRESENTATION

We report a case of a 26-years-old male diagnosed with Crohn's disease 4 months prior to an elective laparoscopic ileocecectomy. Before the operation, the patient suffered from severe terminal ileitis and typhlitis with signs of micro perforation. 3 weeks following his discharge, the patient arrived at the ER complaining of severe right lower abdominal pain. Computerized Tomography (CT) scans revealed a 35 mm ileocolic pseudoaneurysm that was treated urgently with coil-embolization via angiography.

DISCUSSION

Until recently, few reports regarding the involvement of pseudoaneurysm of mesenteric arteries in relation to bowel resection surgeries have been reported. It is believed that the chronic inflammatory process induces a potent effect on the vascular endothelium, leading to thick, inflamed and highly friable mesenteric vessel walls. We propose that the pseudoaneurysm occurred as a result of surgical intervention on a thickened and diseased mesentery artery branch.

CONCLUSION

Inclusion of mesenteric resection in Crohn patients' undergoing bowel resection may be an innovative way to avoid this complication and to reduce recurrence.

Clostridium butyricum alleviates dextran sulfate sodium-induced experimental colitis and promotes intestinal lymphatic vessel regeneration in mice

Background

Inflammatory bowel disease (IBD) is the most common precancerous lesion of colitis-associated colon cancer (CAC). Studies have confirmed that pathological changes in intestinal lymphatic vessels (LVs) significantly promoted the development of IBD-associated carcinogenesis. An imbalance in the microecology of the intestinal flora is a key factor in the progression of IBD. As a result, therapeutic techniques that focus on the relationship between LV regeneration and flora management might be a potential treatment strategy.

Methods

We investigated the role of Clostridium butyricum (C butyricum) in a dextran sulfate sodium (DSS)-induced IBD mouse model. Balb/c mice were given 3% DSS in their drinking water for 8 days to produce acute colitis and simultaneously administrated with C butyricum for 12 days. Hematoxylin and eosin (H&E) staining was used to evaluate the degree of colitis tissue damage. Levels of the lymphatic endothelial cell (LEC)-specific marker LYVE-1 and intestinal expressions of pro-lymphatic vascular endothelial growth factor (VEGF)-C and VEGF-D were determined using immunohistochemical assays.

Results

In a DSS-induced IBD mouse model, we found that butyric acid-producing C butyricum significantly reduced disease activity index (DAI) scores in mice, reversed the shortening of the colon, weakened the degree of damage to colonic epithelial tissues, inhibited lymphocyte infiltration, and reduced pathological damage to the colon. To our knowledge, this is the first time that tissue expressions of LYVE-1, VEGF-C, and VEGF-D have been seen to increase in IBD-model mice after treatment with C butyricum.

Conclusions

Our findings suggest that C butyricum might alleviate IBD in DSS-induced IBD-model mice by promoting intestinal LV regeneration.

Mesenteric SParIng versus extensive mesentereCtomY in primary ileocolic resection for ileocaecal Crohn's disease (SPICY): study protocol for randomized controlled trial

BACKGROUND

There is emerging evidence to suggest that Crohn's disease (CD) may be a disease of the mesentery, rather than of the bowel alone. A more extensive mesenteric resection, removing an increased volume of mesentery and lymph nodes to prevent recurrence of CD, may improve clinical outcomes. This study aims to analyse whether more extensive 'oncological' mesenteric resection reduces the recurrence rate of CD.

METHODS

This is an international multicentre randomized controlled study, allocating patients to either group 1-mesenteric sparing ileocolic resection (ICR), the current standard procedure for CD, or group 2-extensive mesenteric ICR, up to the level of the ileocolic trunk. To detect a clinically relevant difference of 25 per cent in endoscopic recurrence at 6 months, a total of 138 patients is required (including 10 per cent dropout). Patients aged over 16 with CD undergoing primary ICR are eligible. Primary outcome is 6-month postoperative endoscopic recurrence rate (modified Rutgeerts score of greater than or equal to i2b). Secondary outcomes are postoperative morbidity, clinical recurrence, quality of life, and the need for (re)starting immunosuppressive medication. For long-term results, patients will be followed up for up to 5 years to determine the reoperation rate for recurrence of disease at the anastomotic site.

CONCLUSION

Analysing these two treatment strategies in a head-to-head comparison will allow an objective evaluation of the clinical relevance of extensive mesenteric resection in CD. If a clinical benefit can be demonstrated, this could result in changes to guidelines which currently recommend close bowel resection.

REGISTRATION NUMBER

NCT00287612 (http://www.clinicaltrials.gov).

Surgical Strategies to Reduce Postoperative Recurrence of Crohn's Disease After Ileocolic Resection

Postoperative recurrence after ileocaecal resection for fibrostenotic terminal ileal Crohn's disease is a significant issue for patients as it can result in symptom recurrence and requirement for further surgery. There are very few modifiable factors, aside from smoking cessation, that can reduce the risk of postoperative recurrence. Until relatively recently, the surgical technique used for resection and anastomosis had little or no impact on postoperative recurrence rates. Novel surgical techniques such as the Kono-S anastomosis and extended mesenteric excision have shown promise as ways to reduce postoperative recurrence rates. This manuscript will review and discuss the evidence regarding a range of surgical techniques and their potential role in reducing disease recurrence. Some of the techniques have been shown to be associated with significant benefits for patients and have already been integrated into the routine clinical practice of some surgeons, while other techniques remain under investigation. Current techniques such as resection of the mesentery close to the intestine and stapled side to side anastomosis are being challenged. It is looking more likely that surgeons will have a major role to play when it comes to reducing recurrence rates for patients undergoing ileocaecal resection for Crohn's disease.

Magnetic resonance imaging-based body composition is associated with nutritional and inflammatory status: a longitudinal study in patients with Crohn's disease

Objective

To evaluate the changes in magnetic resonance imaging-based body composition parameters during follow-ups in patients with Crohn's disease (CD).

Methods

Between November 1, 2017, and June 30, 2021, patients diagnosed with CD, who underwent two or more magnetic resonance enterography (MRE) scans at our institution were retrospectively reviewed. The baseline and one subsequent follow-up scan for each patient were paired to form longitudinal comparisons. Skeletal muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) indexes were calculated from tissue areas measured at the third lumbar vertebra level per scan, standardized by dividing the height² and lumbar height² (height_L1–L5). We also assessed the correlation between changes in VAT to total adipose tissue ratio (VA/TA index) and CD activity scores (5-point MRE classification) using Spearman’s correlation analysis. A multivariate linear regression model was used to adjust for the follow-up duration and treatment type.

Results

Overall, 49 patients (with 49 paired scans) were enrolled. VA/TA index changes were negatively correlated with changes in skeletal muscle index (SMI; r =  − 0.339, p < 0.05). The VA/TA index (52.69 ± 10.66% vs. 49.18 ± 10.80%, p < 0.001) and the total MRE score (8.0 ± 3.9 vs. 5.7 ± 3.4, p < 0.001) decreased significantly during follow-up, regardless of follow-up duration and treatment type (both p > 0.05). Changes in total MRE score were negatively correlated with SMI changes (r =  − 0.408, p < 0.01) but positively correlated with VA/TA index changes (r = 0.479, p < 0.01).

Conclusion

An increase in SMI and a decrease in VA/TA index could reflect improved nutritional and inflammatory status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-021-01121-3.

The Clinical Significance of Mesenteric Lymphocytes in Human Colorectal Cancer

Objective

The mesentery is a potential site of residual tumor in patients with colorectal cancer (CRC). However, the mesenteric immune microenvironment remains unclear. In this study, we investigated the immune landscape of the mesentery, particularly the role of lymphocytes and its association with the clinicopathological characteristics of CRC.

Methods

Flow cytometry was used to detect lymphocytes in the paired mesenteric tissue specimens adjacent to the colorectal tumors and normal mesenteric tissue specimens 10 cm away from the colorectal tumor edge and preoperative peripheral blood samples obtained from patients with CRC who underwent surgery. T-distributed stochastic neighbor embedding was utilized to analyze multiparameter flow cytometry data. Multiplex immunohistochemistry was performed to evaluate T cells subsets in the paired mesentery adjacent to the colorectal tumors and normal mesentery. The Fisher’s exact test and non-parametric Wilcoxon’s matched-pairs tests were used for statistical analysis. The non-parametric Mann-Whitney U test was used to determine associations between percentage data and clinical parameters of patients with CRC.

Results

We found that immune cells in the normal mesentery were mainly of lymphoid lineage. Compared with peripheral blood, the normal mesentery showed decreased NK cells and the CD4/CD8 ratio and increased CD3⁺ CD56⁺, memory CD4⁺ T, memory CD8⁺ T, CD4⁺ tissue-resident memory T (TRM), and CD8⁺ TRM cells. Compared with the normal mesentery, the mesentery adjacent to the colorectal tumor showed increased B and regulatory T cells and decreased NK, CD3⁺ CD56⁺, CD4⁺ TRM, and CD8⁺ TRM cells. Moreover, memory CD8⁺ T cells and plasmablasts are negatively correlated with the depth of invasion of CRC. Increased memory CD4⁺ T cells are associated with distant metastasis of CRC and high preoperative serum carcinoembryonic antigen levels.

Conclusion

The mesentery shows a specific immune microenvironment, which differs from that observed in peripheral blood. CRC can alter the mesenteric immune response to promote tumor progression.

Role of Extended Mesenteric Excision in Postoperative Recurrence of Crohn's Colitis: A Single-Center Study

INTRODUCTION

The mesentery is involved in Crohn's disease. The impact of the extent of mesenteric resection on postoperative disease progression in Crohn's disease remains unconfirmed. This study aimed to determine the association between resection of the mesentery and postoperative outcomes in patients with Crohn's colitis (CC) undergoing colorectal surgery.

METHODS

Patients with CC who underwent colorectal resection between January 2000 and December 2018 were reviewed, and the data were gathered from a prospectively maintained database. Patients were divided into 2 groups according to the extent of mesenteric resection, the extensive mesenteric excision (EME) group and the limited mesenteric excision (LME) group. Outcomes including early postoperative morbidities and surgical recurrence were compared between the 2 groups.

RESULTS

Of the 126 patients included, 60 were in the LME group and 66 in the EME group. There was no significant difference between the 2 groups in early postsurgical outcomes except the intraoperative blood loss was increased in the LME group (P = 0.002). Patients in the EME group had a longer postoperative surgical recurrence-free survival time when compared with those in the LME group (P = 0.01). LME was an independent predictor of postoperative surgical recurrence (hazard ratio 2.67, 95% confidence interval 1.04-6.85, P = 0.04). This was further confirmed in the subgroup analysis of patients undergoing colorectal resection and anastomosis (hazard ratio 2.83, 95% confidence interval 1.01-7.96, P = 0.048).

DISCUSSION

In patients undergoing surgery for CC, inclusion of the mesentery is associated with similar short-term outcomes and improved long-term outcomes compared with those seen when the mesentery is retained.

The Revival of Surgery in Crohn's Disease-Early Intestinal Resection as a Reasonable Alternative in Localized Ileitis

Crohn's disease (CD) represents a heterogeneous and complex disease with no curative therapeutic option available to date. Current therapy is mainly antibody-based focusing on the immune system while other treatment alternatives such as surgery are considered to be "last options". However, medical therapy for CD results in mild to severe side effects in a relevant amount of patients and some patients do not respond to the medication. Following that, quality of life is often significantly reduced in this patient cohort, thus, therapeutic alternatives are urgently needed. Updated evidence has revealed that surgery such as ileocecal resection (ICR) might be a potential therapeutic option in case of localized terminal ileitis since resection at early time points improves quality of life and significantly reduces the postoperative need for immunosuppressive medication with low rates of morbidity. In addition, new surgical approaches such as Kono-S anastomosis or inclusion of the mesentery result in significantly reduced rates of disease recurrence and reoperation. Based on the new evidence, the goal of this review is to provide an update on the role of surgery as a reasonable alternative to medical therapy in the interdisciplinary treatment of patients with CD.

Predictive Value of CT Enterography Index for Postoperative Intra-abdominal Septic Complications in Patients With Crohn's Disease: Implications for Surgical Decision-Making

BACKGROUND

Postoperative intra-abdominal septic complications in patients with Crohn's disease undergoing intestinal resection and anastomosis are frequent and difficult to manage.

OBJECTIVE

This study sought to explore the value of preoperative CT enterography to predict intra-abdominal septic complications.

DESIGN

This was a retrospective and prospective observational study.

SETTINGS

This study was conducted in a tertiary referral hospital.

PATIENTS

Patients with Crohn's disease undergoing primary intestinal resection were enrolled in our study.

MAIN OUTCOME MEASURES

The CT enterography severity index was calculated and its ability to predict intra-abdominal septic complications evaluated by multivariate analyses. A prospective study was then performed to assess the reliability of this CT enterography index.

RESULTS

The incidence of postoperative intra-abdominal septic complications in patients undergoing a 1-stage procedure was significantly higher than those undergoing a 2-stage procedure (3/103 vs 24/241; 2.9% vs 10.0%; p = 0.026). A multivariate analysis identified 5 CT enterography parameters, including mesenteric fibrofatty proliferation, intra-abdominal abscess or phlegmon, intestinal fistula, peritoneal effusion, and intestinal dilatation with stricture to be independent predictors of intra-abdominal septic complications (p < 0.001). A nomogram model based on these 5 parameters was constructed. A receiver operating characteristic analysis identified a CT enterography nomogram score cutoff of 175 as a predictor of intra-abdominal septic complications with a sensitivity of 83.3% and a specificity of 85.3%. In the prospective study, those patients with a CT enterography nomogram score >175 were assigned to the 2-stage group, which resulted in a similar intra-abdominal septic complication incidence in those undergoing intestinal resection with or without anastomosis (2/82 vs 2/34; p = 0.355).

LIMITATIONS

This study was limited by its single-center scope.

CONCLUSIONS

Preoperative CT enterography findings may predict postoperative outcomes and help determine surgical approach in Crohn's disease. Patients with worse intra-abdominal findings confirmed by CT enterography may benefit from stoma creation after intestinal resection. See Video Abstract at http://links.lww.com/DCR/B588.

EL VALOR PREDICTIVO DEL NDICE ENTEROGRFICO POR TOMOGRAFA COMPUTADA PARA LAS COMPLICACIONES SPTICAS INTRAABDOMINALES POSTOPERATORIAS EN PACIENTES CON ENFERMEDAD DE CROHN IMPLICACIONES PARA LA TOMA DE DECISIONES QUIRRGICAS

ANTECEDENTES:Las complicaciones sépticas intra-abdominales postoperatorias en pacientes con enfermedad de Crohn sometidos a resección intestinal y anastomosis son frecuentes y difíciles de manejar.OBJETIVO:Este estudio buscó explorar el valor del índice enterográfico por tomografía computada en el pré-operatorio y así poder predecir futuras complicaciones sépticas intra-abdominales.DISEÑO:Estudio observacional retro-prospectivo.AJUSTE:Investigación realizada en un hospital de referencia terciaria.PACIENTES:Se incluyeron en nuestro estudio pacientes con enfermedad de Crohn sometidos a una resección intestinal primaria.PRINCIPALES MEDIDAS DE RESULTADO:Se calculó el índice de gravedad de la enterografía por tomografía axial computada y se evaluó su capacidad para predecir las complicaciones sépticas intra-abdominales mediante un análisis multivariado. Luego se realizó un estudio prospectivo para evaluar la confiabilidad del índice enterográfico por tomografía axial computada.RESULTADOS:La incidencia de complicaciones sépticas intra-abdominales postoperatorias en pacientes sometidos a un procedimiento de un solo tiempo fue significativamente mayor que aquellos sometidos a un procedimiento de dos tiempos (3/103 frente a 24/241; 2,9% frente a 10,0%; p = 0,026). El análisis multivariado identificó cinco parámetros enterográficos por tomografía axial computada, incluidos la proliferación fibrograsa mesentérica, el absceso o flegmón intra-abdominal, la fístula entérica, el derrame peritoneal y la dilatación intestinal debido a estenosis como predictores independientes de complicaciones sépticas intra-abdominales (p <0,001). Se construyó un modelo de Nomograma basado en estos cinco parámetros. Un análisis de las características operatorias del receptor identificó una puntuación de cohortes del nomograma de la enterografía por tomografía axial computada de 175 como predictor de complicaciones sépticas intra-abdominales con una sensibilidad del 83,3% y una especificidad del 85,3%. En el estudio prospectivo, los pacientes con puntuación de nomograma enterográfico por tomografía axial computada superior a 175 fueron asignados al grupo en dos tiempos, lo que resultó en una incidencia similar de complicaciones sépticas intra-abdominales en aquellos sometidos a resección intestinal con o sin anastomosis (2/82 vs. 2/34; p = 0,355).LIMITACIONES:Este estudio estuvo limitado por su alcance unicéntrico.CONCLUSIÓN:Los hallazgos enterográficos por tomografía axial computada pré-operatoria pueden predecir ciertos resultados postoperatorios y ayudar a determinar el abordaje quirúrgico en la enfermedad de Crohn. Los pacientes con peores hallazgos intra-abdominales confirmados por enterografía en la tomografía axial computada podrían beneficiarse de la creación de un estoma después de la resección intestinal. Consulte Video Resumen en http://links.lww.com/DCR/B588. (Traducción-Dr Xavier Delgadillo).

Cellular and molecular mediators of lymphangiogenesis in inflammatory bowel disease

Background

Recent studies reporting the intricate crosstalk between cellular and molecular mediators and the lymphatic endothelium in the development of inflammatory bowel diseases (IBD) suggest altered inflammatory cell drainage and lymphatic vasculature, implicating the lymphatic system as a player in the occurrence, development, and recurrence of intestinal diseases. This article aims to review recent data on the modulatory functions of cellular and molecular components of the IBD microenvironment on the lymphatic system, particularly lymphangiogenesis. It serves as a promising therapeutic target for IBD management and treatment. The interaction with gut microbiota is also explored.

Main text

Evidence shows that cells of the innate and adaptive immune system and certain non-immune cells participate in the complex processes of inflammatory-induced lymphangiogenesis through the secretion of a wide spectrum of molecular factors, which vary greatly among the various cells. Lymphangiogenesis enhances lymphatic fluid drainage, hence reduced infiltration of immunomodulatory cells and associated-inflammatory cytokines. Interestingly, some of the cellular mediators, including mast cells, neutrophils, basophils, monocytes, and lymphatic endothelial cells (LECs), are a source of lymphangiogenic molecules, and a target as they express specific receptors for lymphangiogenic factors.

Conclusion

The effective target of lymphangiogenesis is expected to provide novel therapeutic interventions for intestinal inflammatory conditions, including IBD, through both immune and non-immune cells and based on cellular and molecular mechanisms of lymphangiogenesis that facilitate inflammation resolution.

Lymphedema alters lipolytic, lipogenic, immune and angiogenic properties of adipose tissue: a hypothesis-generating study in breast cancer survivors

Later stages of secondary lymphedema are associated with the massive deposition of adipose tissue (AT). The factors driving lymphedema-associated AT (LAT) expansion in humans remain rather elusive. We hypothesized that LAT expansion could be based on alterations of metabolic, adipogenic, immune and/or angiogenic qualities of AT. AT samples were acquired from upper limbs of 11 women with unilateral breast cancer-related lymphedema and 11 healthy women without lymphedema. Additional control group of 11 female breast cancer survivors without lymphedema was used to assess systemic effects of lymphedema. AT was analysed for adipocyte size, lipolysis, angiogenesis, secretion of cytokines, immune and stem cell content and mRNA gene expression. Further, adipose precursors were isolated and tested for their proliferative and adipogenic capacity. The effect of undrained LAT- derived fluid on adipogenesis was also examined. Lymphedema did not have apparent systemic effect on metabolism and cytokine levels, but it was linked with higher lymphocyte numbers and altered levels of several miRNAs in blood. LAT showed higher basal lipolysis, (lymph)angiogenic capacity and secretion of inflammatory cytokines when compared to healthy AT. LAT contained more activated CD4+ T lymphocytes than healthy AT. mRNA levels of (lymph)angiogenic markers were deregulated in LAT and correlated with markers of lipolysis. In vitro, adipose cells derived from LAT did not differ in their proliferative, adipogenic, lipogenic and lipolytic potential from cells derived from healthy AT. Nevertheless, exposition of preadipocytes to LAT-derived fluid improved their adipogenic conversion when compared with the effect of serum. This study presents results of first complex analysis of LAT from upper limb of breast cancer survivors. Identified LAT alterations indicate a possible link between (lymph)angiogenesis and lipolysis. In addition, our in vitro results imply that AT expansion in lymphedema could be driven partially by exposition of adipose precursors to undrained LAT-derived fluid.

Chylomicrons-Simulating Sustained Drug Release in Mesenteric Lymphatics for the Treatment of Crohn's-Like Colitis

BACKGROUND AND AIMS

Alteration to both the structures and functions of mesenteric lymphatic vessels is a typical hallmark of Crohn's disease [CD]. Dysfunctional lymphatics was observed in patients with both CD and experimental colitis, suggesting mesenteric lymphatics could be potential therapeutic targets. This study aimed to develop a nano-delivery system which can enhance drug delivery in mesenteric lymphatic tissue [MLT] and evaluate the therapeutic effects in Crohn's colitis.

METHODS

We designed a mesoporous silica nanoparticle [MSN] conjugated with long-chain fatty acid [LMSN] and covered with enteric coating [ELMSN] which can be specifically transported via the mesenteric lymphatic system. The therapeutic efficacy of laquinimod-loaded nanoparticles [LAQ@ELMSN] was evaluated in the well-established interleukin [IL]-10-/- spontaneous experimental colitis.

RESULTS

ELMSNs induced sustainable drug release that markedly increased drug concentration in MLT. In experimental colitis, the lymphatics-targeting drug delivery system suppressed lymphangitis and promoted lymphatic drainage. The downregulation of pro-inflammatory cytokines and the downstream NF-κB-related proteins efficiently inhibited lymphangiogenesis and restored tight junctions of mesenteric lymphatic vessels [MLVs]. LAQ@ELMSN showed a superior therapeutic effect in ameliorating intestinal inflammation compared with free drug administration. Alteration of gut microbiota and metabolites in experimental colitis was also reversed by LAQ@ELMSN.

CONCLUSION

Our study demonstrates a convenient, orally administered drug delivery system which enhances drug release in MLT. The results confirm the contribution of the mesenteric lymphatic system to the pathogenesis of gut inflammation and shed light on the application of lymphatics-targeting drug delivery therapy as a potential therapeutic strategy for CD treatment.

Fibrotic Phenotype of Peritumour Mesenteric Adipose Tissue in Human Colon Cancer: A Potential Hallmark of Metastatic Properties

The impact of tumour associated stroma on cancer metastasis is an emerging field. However, cancer associated genes in peritumoral adipose tissue (pAT) in human colon cancer have not been explored. The aim of this study was to identify differentially expressed genes (DEGs) associated with cancer pathways in mesenteric pAT compared with adjacent adipose tissue. In total, nine patients with colon cancer pathological stage T2/T4 were employed in this study. DEGs were identified in 6 patients employing Nanostring PanCancer Pathway Panel and pathway enrichment analyses were performed. Differential expression of the 5 most up-regulated and 2 down regulated genes was validated with qRT-PCR. Results showed collagen type I alpha 1 chain (COL1A1) p = 0.007; secreted frizzled related protein (SFRP2) p = 0.057; fibroblast growth factor 7 (FGF7) not significant (ns); phospholipase A2, group IIA (PLA2G2A) ns; nerve growth factor receptor (NGFR) ns; lymphoid enhancer binding factor 1 (LEF1) p = 0.03; cadherin 1, Type 1, E-cadherin (epithelial) (CDH1) 0.09. Results have highlighted down-regulation of the Wingless/Integrated (Wnt) pathway in mesenteric pAT compared to distal adipose tissue. Highly upregulated genes in mesenteric pAT were involved in extracellular matrix (ECM)-receptor interactions and focal adhesion. Highly down regulated genes were involved in the cell cycle. Immunohistochemistry revealed differential distribution of COL1A1 showing maximum levels in tumour tissue and gradually decreasing in distant adipose tissue. COL1A1 and down regulation of Wnt pathway may have a role in local invasion and distant metastasis. COL1A1 may represent a stromal prognostic biomarker and therapeutic target in colon cancer.

Degree of Creeping Fat Assessed by Computed Tomography Enterography is Associated with Intestinal Fibrotic Stricture in Patients with Crohn's Disease: A Potentially Novel Mesenteric Creeping Fat Index

BACKGROUND AND AIMS

Emerging evidence points to a link between creeping fat and the pathogenesis of Crohn's disease [CD]. Non-invasive assessment of the severity of creeping fat on cross-sectional imaging modality has seldom been investigated. This study aimed to develop and characterize a novel mesenteric creeping fat index [MCFI] based on computed tomography [CT] in CD patients.

METHODS

MCFI was developed based on vascular findings on CT in a retrospective cohort [n = 91] and validated in a prospective cohort [n = 30]. The severity of creeping fat was graded based on the extent to which mesenteric fat extended around the intestinal circumference using the vessels in the fat as a marker. The accuracy of MCFI was assessed by comparing it with the degree of creeping fat observed in surgical specimens. The relationship between MCFI and fibrostenosis was characterized by determining if these correlated. The accuracy of MCFI was compared with other radiographic indices [i.e. visceral to subcutaneous fat area ratio and fibrofatty proliferation score].

RESULTS

In the retrospective cohort, MCFI had moderate accuracy in differentiating moderate-severe from mild fibrostenosis (area under the receiver operating characteristic [ROC] curve [AUC] = 0.799; p = 0.000). ROC analysis in the retrospective cohort identified a threshold MCFI of > 3 which accurately differentiated fibrostenosis severity in the prospective cohort [AUC = 0.756; p = 0.018]. An excellent correlation was shown between MCFI and the extent of fat wrapping in specimens in the prospective cohort [r = 0.840, p = 0.000]. Neither visceral to subcutaneous fat area ratio nor fibrofatty proliferation score correlated well with the degree of intestinal fibrosis.

CONCLUSIONS

MCFI can accurately characterize the extent of mesenteric fat wrapping in surgical specimens. It may become another non-invasive measure of CD fibrostenosis.

Greater Peripouch Fat Area on CT Image Is Associated with Chronic Pouchitis and Pouch Failure in Inflammatory Bowel Diseases Patients

BACKGROUND

The causes of chronic antibiotic refractory pouchitis (CARP) and pouch failure in inflammatory bowel disease (IBD) patients remain unknown. Our previous small study showed peripouch fat area measured by MRI was associated with pouchitis.

AIMS

To explore the relationship between peripouch fat area on CT imaging and pouch outcomes.

METHODS

This is a historical cohort study. Demographic, clinical, and radiographic data of IBD patients with abdominal CT scans after pouch surgery between 2002 and 2017 were collected. Peripouch fat areas and mesenteric peripouch fat areas were measured on CT images at the middle pouch level.

RESULTS

A total of 435 IBD patients were included. Patients with higher peripouch fat areas had a higher prevalence of CARP. Univariate analyses demonstrated that long duration of the pouch, high weight or body mass index, the presence of primary sclerosing cholangitis or other autoimmune disorders, and greater peripouch fat area or mesenteric peripouch fat area were risk factors for CARP. Multivariable analyses demonstrated that the presence of primary sclerosing cholangitis or autoimmuned disorders, and greater peripouch fat area (odds ratio [OR] 1.031; 95% confidence interval [CI] 1.016-1.047, P < 0.001) or mesenteric peripouch fat area were independent risk factors for CARP. Of the 435 patients, 139 (32.0%) had two or more CT scans. Multivariable Cox proportional hazard analyses showed that "peripouch fat area increase ≥ 15%" (OR 3.808, 95%CI 1.703-8.517, P = 0.001) was an independent predictor of pouch failure.

CONCLUSIONS

A great peripouch fat area measured on CT image is associated with a higher prevalence of CARP, and the accumulation of peripouch fat is a risk factor for pouch failure. The assessment of peripouch fat may be used to monitor the disease course of the ileal pouch.

Pouch wall thickness and floppy pouch complex

BACKGROUND

Floppy pouch complex (FPC) consists of disease phenotypes in patients with ileal pouches, including pouch prolapse, afferent limb syndrome, enterocele, redundant loop, and pouch folding. Our recent study demonstrated that lower body weight, lower peripouch fat, family history of inflammatory bowel disease (IBD), female gender, and dyschezia are risk factors for FPC patients with IBD. The aims of this study were to assess the relationship between pouch wall thickness and FPC, and to investigate the association between inflamed and non-inflamed pouch wall thickness.

METHODS

This case-control study included all eligible patients with FPC from our prospectively maintained, IRB-approved Pouchitis Registry from 2011 to 2017. We measured pouch wall thickness of fully distended pouches on cross-sectional abdominal and pelvic imaging. Patients with stoma and non-distended pouches were completely excluded. Risk factors for FPC were analyzed.

RESULTS

A total of 140 out of 451 patients from our were found to have fully distended pouches on imaging. Of the 140 patients, 36 (25.7%) were diagnosed as having FPC. We analyzed pouch wall thickness for each subcategory of FPC as well as non-FPC conditions. The thickness of pouch wall was follows: pouch prolapse (N = 19): 1.5 mm (1.5-2.0), afferent limb syndrome (N = 12): 1.5 mm (1.1-2.0), folded pouch (N = 4): 1.5 mm (1.1-1.9), and redundant pouch (N = 2): 1.3 mm (1.0-1.3). The control group (N = 104) consisting of normal pouch, pouchitis, cuffitis, Crohn's disease of the pouch, and pouch sinus with median pouch wall thickness of 1.5 mm, 2.3 mm, 2.0 mm, 2.0 mm, and 1.5 mm, respectively. There were significant differences in pouch wall thickness between normal or non-inflamed pouch versus pouchitis versus cuffitis versus Crohn's disease of the pouch with p values of 0.01, 0.04, 0.05, and 0.049, respectively.

CONCLUSION

Patients with FPC were shown to have thin pouch wall, which those with inflammatory conditions of the pouch tended to have thick pouch wall. These findings will have implications in both diagnosis and investigation of etiopathogenesis of these disorders.

Magnetic resonance imaging assessment of body composition parameters in Crohn's disease

BACKGROUND

Body composition, currently evaluated by computed tomography scan, is related to poor evolution and severity of Crohn's disease (CD). Few MRI studies have been performed, yet it is the most commonly used imaging modality for the surveillance of the disease.

AIM

Evaluate the feasibility of MRI body composition measurement and compare the variation according to the activity of the disease.

METHODS

A cohort of 132 consecutive patients was studied. The visceral adiposity index (VAI), subcutaneous adiposity index (SAI) and skeletal muscle index (SMI) were measured. Patients were divided into 2 groups according to disease activity. Sarcopenic status was defined according to the cut off value (SMI < 38.9 cm²/m² in women and < 54.4 cm²/m² in men).

RESULTS

MRI measurements of body composition parameters were feasible and reproducible. After adjustment, sarcopenia was more common (2.07 [1.02; 4.27], p = 0.046), and the SMI (-4.90 [-9.36; -0.431], p = 0.032) was lower in active disease. The SAI was lower (-14.7 [-29.8; 0.258], p = 0.054) in active disease. The VAI tended to be higher with active disease (3.91 [-3.50; 11.9], p = 0.34), and the VAI/SAI+VAI ratio was higher (9.40 [4.72; 14.1], p<0.001).

CONCLUSION

Assessment of body composition is feasible and reproducible in routine MR and parameters are related to disease activity.

Lipopolysaccharides modulate intestinal epithelial permeability and inflammation in a species-specific manner

Patients presenting with Inflammatory bowel disease have been shown to exhibit an altered microbiome in both Crohn's disease and Ulcerative colitis. This shift in the microbial content led us to question whether several of these microbes are important in inflammatory processes present in these diseases and more specifically whether lipopolysaccharides from the gram-negative cell wall differentially stimulates resident cells. We, therefore, investigated the possible contribution of five major species of gram-negative bacteria found to be altered in presence during disease progression and evaluate their pathogenicity through LPS. We demonstrated that LPS from these different species had individual capacities to induce NF-κB and pro-inflammatory IL-8 production from HEK-TLR4 cells in a TLR4 dependent manner. Additional work using human intestinal colonic epithelial cell monolayers (Caco-2) demonstrated that the cells responded to the serotype specific LPS in a distinct manner, inducing many inflammatory mediators such as TNF-α and IL-10 in significantly altered proportions. Furthermore, the permeability of Caco-2 monolayers, as a test for their ability to alter intestinal permeability, was also differentially altered by the serotype specific LPS modulating trans-epithelial electrical resistance, small molecule movement, and tight junction integrity. Our results suggest that specific species of bacteria may be potentiating the pathogenesis of IBD and chronic inflammatory diseases through their serotype specific LPS responses.

Lower peripouch fat area is related with increased frequency of pouch prolapse and floppy pouch complex in inflammatory bowel disease patients

BACKGROUND

Pouch prolapse is a rare pouch complication which often leads to pouch failure in inflammatory bowel disease (IBD) patients. Its exact cause remains unknown. Floppy pouch complex (FPC) was defined as the presence of any one of the following pouch disorders: pouch prolapse, afferent limb syndrome (ALS), redundant loop, and pouch folding. We aimed to explore the role of peripouch fat area in the occurrence of pouch prolapse and FPC.

METHODS

Pouch patients with available pouchoscopy and abdominal CT scans who were followed up between 2011 and 2017 in Cleveland Clinic were reviewed. Peripouch fat was measured on CT images.

RESULTS

Of the 93 included patients, 31 were females; 87 had J pouches and 6 had S pouches. The median duration of pouch was 8.0 (interquartile range [IQR] 5.0-16.5) years. A total of 18 cases (19.4%, 18/93) were identified as FPC, including 12 pouch prolapse, 5 ALS, 1 redundant loop, and 3 pouch folding. Patients with pouch prolapse had lower peripouch fat area (13.6 (9.3-18.5) vs. 27.6 (11.0-46.2)cm², P = 0.022) than those without. Patients with FPC had lower peripouch fat area (15.4 (11.4-20.6) vs. 27.6 (11.0-46.9)cm², P = 0.040) than those without. Univariate and multivariate analyses demonstrated that lower peripouch fat area, lower weight, and family history of IBD were independent predictors of pouch prolapse and FPC.

CONCLUSIONS

A lower peripouch fat area was observed in inflammatory bowel disease patients with pouch prolapse and FPC. Longitudinal studies are needed to further elucidate the role of peripouch fat in the pathogenesis of pouch prolapse and FPC.

Mesenteric excision surgery or conservative limited resection in Crohn's disease: study protocol for an international, multicenter, randomized controlled trial

Background

The structures of the mesentery including adipose tissue, nerves, and lymphatics play an important role in the pathogenesis and disease progression of Crohn’s disease (CD). Conventional surgical resection for CD usually does not involve resecting the mesentery en bloc with the specimen. This contrasts with complete mesocolic excision (CME) in colorectal cancer, which involves radical resection of the mesentery. Preliminary evidence from smaller studies suggests that applying the principle of mesocolic excision to CD surgery may reduce the risk of postoperative recurrence. This randomized controlled trial is designed to test whether applying the principles of mesocolic excision to CD results in reduced postoperative recurrence. It also aims to evaluate intra- and postoperative morbidity between the two approaches.

Methods

This international, multicenter, randomized controlled trial will randomize patients (n = 116) scheduled to undergo primary ileocolic resection to either receive extensive mesenteric excision (EME) or conventional ileocolic resection with limited mesenteric excision (LME). Five sites will recruit patients in three countries. In the EME group, the mesentery is resected following CME, while avoiding the root region, i.e., 1 cm from the root of the ileocolic artery and vein. In the LME group, the mesentery is retained, i.e., “close shave” or < 3 cm from the border of bowel. The primary end point will be surgical recurrence after surgery. The secondary end points will be the postoperative endoscopic and clinical recurrence, and intra- and postoperative morbidity. Demographics, risk factors, laboratory investigations, endoscopy, postoperative prophylaxis and imaging examination will be assessed. Analysis of the primary outcome will be on an intention-to-treat basis.

Discussion

If mesocolic excision in CD reduces postoperative disease recurrence and does not increase morbidity, this trial has the potential to change practice and reduce recurrence of CD after surgical resection.

Trial registration

Clinical Trials.gov, ID: NCT03769922. Registered on February 27, 2019.

The Adipokine Metrnl Ameliorates Chronic Colitis in Il-10-/- Mice by Attenuating Mesenteric Adipose Tissue Lesions During Spontaneous Colitis

BACKGROUND

Crosstalk between mesenteric adipose tissue [MAT] and the intestines affects the progression of Crohn's disease [CD]. The adipokine metrnl regulates adipocyte function and has anti-inflammatory activity. We aimed to explore metrnl expression in CD MAT, investigate the influence of metrnl on the experimental colitis disease course and determine the mechanism underlying this effect.

METHODS

Metrnl expression in MAT specimens obtained from patients with and without CD was tested by immunohistochemistry. Male Il-10-/- mice with spontaneous enteritis were divided into positive control and metrnl-treated [Metrnl-Fc, 10 mg/kg/d, intraperitoneally, 8 weeks] groups. Age-matched male wild-type [WT] mice were used as negative controls. The effects of metrnl on enteritis and mesenteric lesions and the potential controlling mechanisms were evaluated.

RESULTS

Metrnl expression was higher in human CD MAT than in control MAT. Systemic delivery of metrnl significantly ameliorated chronic colitis in Il-10-/- mice, as demonstrated by decreases in the disease activity index, inflammatory score and proinflammatory mediators. The protective effects of metrnl on MAT included reduced mesenteric hypertrophy, increased adipocyte size, improved adipocyte intrinsic function and ameliorated inflammation. Metrnl treatment activated STAT5/PPAR-γ signaling and promoted adipocyte differentiation in the MAT.

CONCLUSIONS

Metrnl expression was increased in the MAT of CD patients. Metrnl administration attenuated mesenteric lesions by promoting adipocyte function and differentiation partly through STAT5/PPAR-γ signaling pathway activation, thereby ameliorating CD-like colitis in mice.