Multiple pathogenic roles of microvasculature in inflammatory bowel disease: a Jack of all trades

Leveraging Organ-on-Chip Models to Investigate Host-Microbiota Dynamics and Targeted Therapies for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic gastrointestinal disease with drastically increasing incidence rates. Due to its multifactorial etiology, a precise investigation of the pathogenesis is extremely difficult. Although reductionist cell culture models and more complex disease models in animals have clarified the understanding of individual disease mechanisms and contributing factors of IBD in the past, it remains challenging to bridge research and clinical practice. Conventional 2D cell culture models cannot replicate complex host-microbiota interactions and stable long-term microbial culture. Further, extrapolating data from animal models to patients remains challenging due to genetic and environmental diversity leading to differences in immune responses. Human intestine organ-on-chip (OoC) models have emerged as an alternative in vitro model approach to investigate IBD. OoC models not only recapitulate the human intestinal microenvironment more accurately than 2D cultures yet may also be advantageous for the identification of important disease-driving factors and pharmacological interventions targets due to the possibility of emulating different complexities. The predispositions and biological hallmarks of IBD focusing on host-microbiota interactions at the intestinal mucosal barrier are elucidated here. Additionally, the potential of OoCs to explore microbiota-related therapies and personalized medicine for IBD treatment is discussed.

Guided Multispectral Optoacoustic Tomography for 3D Imaging of the Murine Colon

Multispectral optoacoustic tomography is a promising medical imaging modality that combines light and sound to provide molecular imaging information at depths of several centimeters, based on the optical absorption of endogenous chromophores, such as hemoglobin. Assessment of inflammatory bowel disease has emerged as a promising clinical application of optoacoustic tomography. In this context, preclinical studies in animal models are essential to identify novel disease-specific imaging biomarkers and understand findings from emerging clinical pilot studies, however to-date, these studies have been limited by the precise identification of the bowel wall. Herein, a transrectal-absorber guide is applied, serving as a high-contrast landmark for 3D optoacoustic tomography of the colon. This study shows that guided multispectral optoacoustic tomography is able to measure changes in blood oxygenation status over the course of acute, chemically-induced colitis in mice and correlates with standard disease activity scores. This novel approach depicts intestinal hemoglobin composition non-invasively during murine inflammation. These results underscore the potential for optoacoustic imaging in translational inflammatory bowel disease research.

Identification of Angiogenesis-Related Gene Signatures and Prediction of Potential Therapeutic Targets in Ulcerative Colitis Using Integrated Bioinformatics

Objective

This study aims to clarify angiogenesis mechanisms in ulcerative colitis and identify potential therapeutic targets.

Methods

The Gene Expression Omnibus (GEO) database was used to obtain expression profiles and clinical data for UC and healthy colon tissues. Angiogenesis-related gene sets were acquired from GeneCards. Differential expression analysis and weighted gene co-expression network analysis (WGCNA) identified UC-associated hub genes. The CIBERSORT algorithm assessed immune cell infiltration. Analyses of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to determine biological mechanisms. External datasets were utilized to validate and characterize the angiogenesis-related genes in relation to biological agents. Additionally, an ulcerative colitis mouse model was constructed to verify the key genes' expression using real-time quantitative PCR. To predict potential therapeutic agents, we used the DGIdb database. Molecular docking modeled small molecule binding conformations to key gene targets.

Results

This study identified 1,247 DEGs enriched in inflammatory/immune pathways from UC and healthy colon samples. WGCNA indicated the black and light cyan modules were most relevant. Intersecting these with 89 angiogenesis genes revealed 5 UC-associated hub genes (pdgfrb, vegfc, angpt2, tnc, hgf). Validation via ROC analysis, differential expression, and a mouse model confirmed upregulation, supporting their potential as UC diagnostic biomarkers. Bioinformatics approaches like protein-protein interaction, enrichment analysis, and GSEA revealed involvement in PDGFR and PI3K-Akt signaling pathways. CIBERSORT analysis of immune cell infiltration showed positive correlations between the key genes and various immune cells, especially neutrophils, highlighting angiogenesis-inflammation interplay in UC. A ceRNA network was constructed. Drug prediction and molecular docking revealed potential UC therapies like sunitinib and imatinib targeting angiogenesis.

Conclusion

This study identified and validated five angiogenesis-related genes (pdgfrb, vegfc, angpt2, tnc, hgf) that may serve as diagnostic biomarkers and drug targets for UC.

Microbiota and angiogenesis in the intestinal vasculature

The gut microbiota is responsible for several metabolic functions, producing various metabolites with numerous roles for the host. The gut microbiota plays a key role in constructing the microvascular network in the intestinal villus, depending on the Paneth cells, strategically positioned to coordinate the development of both the microbiota and the microvasculature. The gut microbiota secretes several molecules and chemokines involved in the induction of the secretion of pro-angiogenic factors.

Ocular endothelial dysfunction in pediatric inflammatory bowel disease

OBJECTIVES

To assess ocular microvasculature changes using optical coherence tomography angiography (OCTA) in pediatric patients with inflammatory bowel disease (IBD).

METHODS

Patients (aged 6-18 years) with IBD were recruited between September 2021 and May 2023. All eligible participants underwent comprehensive clinical assessment and laboratory investigation. Patients with functional gastrointestinal disorders served as the controls. This study assessed specific IBD phenotypes, disease duration, clinical and endoscopic activity indices, laboratory markers, and medication histories. OCTA was utilized to evaluate ocular microvasculature changes in both groups.

RESULTS

A total of 63 children (mean age 12.9 ± 3.3 years) were enrolled, comprising 38 in the IBD group (16 ulcerative colitis, 22 Crohn's disease, and 25 in the control group). Most patients in the IBD group were in remission or had mild-to-moderate disease activity at enrollment. Analysis of the OCTA results revealed significant differences in the choroidal luminal area and total choroidal area between the IBD and control groups.

CONCLUSIONS

The study identified distinct ocular microvasculature changes in pediatric IBD patients through OCTA, suggestive of potential systemic endothelial dysfunction. These findings underscore the utility of OCTA in evaluating microvascular alterations associated with pediatric IBD, offering insights into potential systemic complications linked to inflammation in IBD patients.

Current Knowledge on the Preparation and Benefits of Cruciferous Vegetables as Relates to In Vitro, In Vivo, and Clinical Models of Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic condition with a significant economic and social burden. The disease is complex and challenging to treat because it involves several pathologies, such as inflammation, oxidative stress, dysbiosis, and intestinal damage. The search for an effective treatment has identified cruciferous vegetables and their phytochemicals as potential management options for inflammatory bowel disease because they contain prebiotics, probiotics, and anti-inflammatory and antioxidant metabolites essential for a healthy gut. This critical narrative style review provides a robust insight into the pharmacological effects and benefits of crucifers and their documented bioactive compounds in in vitro and in vivo models, as well as clinical inflammatory bowel disease. The review highlights the significant impact of crucifer preparation and the presence of glucosinolates, isothiocyanates, flavonoids, and polyphenolic compounds, which are essential for the anti-inflammatory and antioxidative benefits of cruciferous vegetables, as well as their ability to promote the healthy microbial community and maintain the intestinal barrier. This review may serve as a viable nutritional guide for future research on methods and features essential to developing experiments, preventions, and treatments for inflammatory bowel disease. There is limited clinical information and future research may utilize current innovative tools, such as metabolomics, for adequate knowledge and effective translation into clinical therapy.

A Pro-Regenerative Supramolecular Prodrug Protects Against and Repairs Colon Damage in Experimental Colitis

Structural repair of the intestinal epithelium is strongly correlated with disease remission in inflammatory bowel disease (IBD); however, ulcer healing is not addressed by existing therapies. To address this need, this study reports the use of a small molecule prolyl hydroxylase (PHD) inhibitor (DPCA) to upregulate hypoxia-inducible factor one-alpha (HIF-1α) and induce mammalian regeneration. Sustained delivery of DPCA is achieved through subcutaneous injections of a supramolecular hydrogel, formed through the self-assembly of PEG-DPCA conjugates. Pre-treatment of mice with PEG-DPCA is shown to protect mice from epithelial erosion and symptoms of dextran sodium sulfate (DSS)-induced colitis. Surprisingly, a single subcutaneous dose of PEG-DPCA, administered after disease onset, leads to accelerated weight gain and complete restoration of healthy tissue architecture in colitic mice. Rapid DPCA-induced restoration of the intestinal barrier is likely orchestrated by increased expression of HIF-1α and associated targets leading to an epithelial-to-mesenchymal transition. Further investigation of DPCA as a potential adjunctive or stand-alone restorative treatment to combat active IBD is warranted.

Mechanistic insight: Linking cardiovascular complications of inflammatory bowel disease

Cardiovascular diseases (CVD) are the leading cause of mortality worldwide despite an aggressive reduction of traditional cardiovascular risk factors. Underlying inflammatory conditions such as inflammatory bowel disease (IBD) increase the risk of developing CVD. A broad understanding of the underlying pathophysiological processes between IBD and CVD is required to treat and prevent cardiovascular events in patients with IBD. This review highlights the commonality between IBD and CVD, including dysregulated immune response, genetics, environmental risk factors, altered gut microbiome, stress, endothelial dysfunction and abnormalities, to shed light on an essential area of modern medicine.

Multiparametric MRI for Staging of Bowel Inflammatory Activity in Crohn's Disease with MUSE-IVIM and DCE-MRI: A Preliminary Study

RATIONALE AND OBJECTIVES

To investigate if the combination of multishot diffusion imaging-based multiplexed sensitivity encoding intravoxel incoherent motion (MUSE-IVIM) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is feasible for staging Crohn's disease (CD) activity.

MATERIALS AND METHODS

A total of 65 CD patients were enrolled and analyzed in this retrospective study. The simplified endoscopic score for Crohn's disease (SES-CD) and magnetic resonance index of activity (MaRIA) were used as the reference. The MUSE-IVIM and DCE-MRI data were acquired at 3.0-T MRI scanner and processed by two radiologists. Three MUSE-IVIM parameters: fast apparent diffusion coefficient (ADCfast), slow apparent diffusion coefficient (ADCslow), and the fractional perfusion (Fraction of ADCfast), as well as four DCE-MRI parameters: volume transfer constant (Ktrans), rate constant (Kep), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp) were generated. Intraclass correlation coefficient (ICC), non-parametric test (Kruskal-Wallis H and Mann-Whitney U), logistic regression, receiver operating characteristic analysis, Delong test, and Spearman's correlation test were performed.

RESULTS

According to SES-CD, 116 ileocolonic segments with CD lesions were identified as: inactive, mild, and moderate to severe. With multivariable logistic regression analysis, ADCfast (p < 0.001), Fraction of ADCfast (p = 0.005), Ktrans (p < 0.001) and Kep (p = 0.003) were identified as significant factors for differentiating among the three groups. Binary logistic analyses identified ADCfast (p = 0.001), Ktrans (p = 0.014), and Kep (p = 0.029) as independent predictors for the active status. The combination of ADCfast, Ktrans, and Kep performed better than MaRIA score (p = 0.028), for differentiating inactive and active status. MaRIA score was positively correlated with ADCfast (p < 0.001), Ktrans (p < 0.001), Kep (p < 0.001), and Ve (p = 0.001), however, negatively correlated with Fraction of ADCfast (p < 0.001).

CONCLUSION

The combination of MUSE-IVIM and DCE-MRI has been demonstrated to accurately stage inflammatory activity in CD.

Advances in laser speckle imaging: From qualitative to quantitative hemodynamic assessment

Laser speckle imaging (LSI) techniques have emerged as a promising method for visualizing functional blood vessels and tissue perfusion by analyzing the speckle patterns generated by coherent light interacting with living biological tissue. These patterns carry important biophysical tissue information including blood flow dynamics. The noninvasive, label-free, and wide-field attributes along with relatively simple instrumental schematics make it an appealing imaging modality in preclinical and clinical applications. The review outlines the fundamentals of speckle physics and the three categories of LSI techniques based on their degree of quantification: qualitative, semi-quantitative and quantitative. Qualitative LSI produces microvascular maps by capturing speckle contrast variations between blood vessels containing moving red blood cells and the surrounding static tissue. Semi-quantitative techniques provide a more accurate analysis of blood flow dynamics by accounting for the effect of static scattering on spatiotemporal parameters. Quantitative LSI such as optical speckle image velocimetry provides quantitative flow velocity measurements, which is inspired by the particle image velocimetry in fluid mechanics. Additionally, discussions regarding the prospects of future innovations in LSI techniques for optimizing the vascular flow quantification with associated clinical outlook are presented.

Disruption of intestinal oxygen balance in acute colitis alters the gut microbiome

The juxtaposition of well-oxygenated intestinal colonic tissue with an anerobic luminal environment supports a fundamentally important relationship that is altered in the setting of intestinal injury, a process likely to be relevant to diseases such as inflammatory bowel disease. Herein, using two-color phosphorometry to non-invasively quantify both intestinal tissue and luminal oxygenation in real time, we show that intestinal injury induced by DSS colitis reduces intestinal tissue oxygenation in a spatially defined manner and increases the flux of oxygen from the tissue into the gut lumen. By characterizing the composition of the microbiome in both DSS colitis-affected gut and in a bioreactor containing a stable human fecal community exposed to microaerobic conditions, we provide evidence that the increased flux of oxygen into the gut lumen augments glycan degrading bacterial taxa rich in glycoside hydrolases which are known to inhabit gut mucosal surface. Continued disruption of the intestinal mucus barrier through such a mechanism may play a role in the perpetuation of the intestinal inflammatory process.

Development and validation of a blood routine-based extent and severity clinical decision support tool for ulcerative colitis

Monitoring extent and severity is vital in the ulcerative colitis (UC) follow-up, however, current assessment is complex and low cost-effectiveness. We aimed to develop a routine blood-based clinical decision support tool, Jin's model, to investigate the extent and severity of UC. The multicentre retrospective cohort study recruited 975 adult UC inpatients and sub-grouped into training, internal validation and external validation set. Model was developed by logistics regression for the extent via Montreal classification and for the severity via Mayo score, Truelove and Witts score (TWS), Mayo endoscopic score (MES) and Degree of Ulcerative colitis Burden of Luminal Inflammation (DUBLIN) score. In Montreal classification, left-sided and extensive versus proctitis model achieved area under the receiver operating characteristic curve (AUROC) of 0.78 and 0.81 retrospectively. For severity, Mayo score model, TWS model, MES model and DUBLIN score model achieved an AUROC of 0.81, 0.70, 0.74 and 0.70 retrospectively. The models also were evaluated with satisfactory calibration and clinical unity. Jin's model was free with open access at http://jinmodel.com:3000/ . Jin's model is a noninvasive, convenient, and efficient approach to assess the extent and severity of UC.

Piezo1 in Digestive System Function and Dysfunction

Piezo1, a non-selective cation channel directly activated by mechanical forces, is widely expressed in the digestive system and participates in biological functions physiologically and pathologically. In this review, we summarized the latest insights on Piezo1’s cellular effect across the entire digestive system, and discussed the role of Piezo1 in various aspects including ingestion and digestion, material metabolism, enteric nervous system, intestinal barrier, and inflammatory response within digestive system. The goal of this comprehensive review is to provide a solid foundation for future research about Piezo1 in digestive system physiologically and pathologically.

Assessment of Ileal Crohn's Disease Activity by Gastrointestinal Ultrasound and MR Enterography: A Pilot Study

INTRODUCTION

In some cases, there may be a discrepancy between the symptomatology alleged by Crohn's disease (CD) patients and the results of laboratory tests or imaging investigations. Ileocolonoscopy with biopsy is the primary investigation for diagnosing and monitoring CD patients. Cross-sectional imaging techniques such as CT or MR enterography (MRE) and intestinal ultrasonography (IUS) have been proposed as complementary methods to colonoscopy for a complete evaluation of this category of patients. This study aims to identify the role of IUS, contrast-enhanced ultrasound (CEUS) and MRE in evaluating ileal CD activity, using clinical severity scores (Crohn's disease activity index-CDAI, Harvey-Bradshaw index-HBI) and faecal calprotectin or C-reactive protein (CRP) levels as reference methods.

MATERIALS AND METHODS

A total of 44 adult patients with ileal CD confirmed using an ileocolonoscopy with biopsy and histopathological examination were assessed by IUS, CEUS and MRE. The evaluation of the disease activity based on the results obtained from the cross-sectional imaging tests was carried out by using some severity scores available in the literature. The sensitivity and specificity of IUS + CEUS and MRE for differentiating active from inactive forms of CD were determined using CDAI, HBI, faecal calprotectin and CRP as reference methods. The accuracy of the results was assessed by the receiver operating characteristics method. The Pearson correlation coefficient was used to determine the types of correlation. A p-value less than 0.05 suggested a statistically significant relationship.

RESULTS

Compared to CDAI, the best correlation was identified for Limberg score (r = 0.667, 95% confidence interval (CI) [0.46, 0.8], p < 0.001), followed by MaRIAs score (r = 0.614, 95% CI [0.39, 0.77], p < 0.001). A sensitivity of 93.33% and a specificity of 71.43% (AUC = 0.98) were demonstrated in the case of Limberg score for differentiating patients with active disease from those in remission and for MaRIAs score a sensitivity of 100.00% and a specificity of 57.14% (AUC = 0.97). Regarding HBI, the best correlation was observed for MaRIAs score (r = 0.594, 95% CI [0.36, 0.76], p < 0.001). Also, faecal calprotectin showed the best correlation with MaRIAs score (r = 0.697, 95% CI [0.46, 0.84], p < 0.001), but in the case of CRP, there was only a weak correlation for all evaluated scores.

CONCLUSIONS

Although magnetic resonance imaging does not appear to be superior to ultrasonography in terms of accuracy for differentiating active forms of CD from those in remission, the results of our study suggest that MRE associates a better correlation with clinical severity scores and faecal calprotectin levels compared to ultrasonography. More studies are needed to validate these results.

Gut vascular barrier in the pathogenesis and resolution of Crohn's disease: A novel link from origination to therapy

The gut vascular barrier (GVB) is the deepest layer of the gut barrier. It mainly comprised gut vascular endothelial cells, enteric glial cells, and pericytes. The GVB facilitates nutrient absorption and blocks bacterial translocation through its size-restricted permeability. Accumulating evidence suggests that dysfunction of this barrier correlates with several clinical pathologies including Crohn's disease (CD). Significant progress has been made to elucidate the mechanism of GVB dysfunction and to confirm the participation of disrupted GVB in the course of CD. However, further analyses are required to pinpoint the specific roles of GVB in CD pathogenesis. Many preclinical models and clinical trials have demonstrated that various agents are effective in protecting the GVB integrity and thus providing a potential CD treatment strategy. Through this review, we established a systemic understanding of the role of GVB in CD pathogenesis and provided novel insights for GVB-targeting strategies in CD treatment.

A vascularized crypt-patterned colon model for high-throughput drug screening and disease modelling

The colon serves as a primary target for pharmaceutical compound screening and disease modelling. To better study colon diseases and develop treatments, engineered in vitro models with colon-specific physiological features are required. Existing colon models lack integration of colonic crypt structures with underlying perfusable vasculature, where vascular-epithelial crosstalk is affected by disease progression. We present a colon epithelium barrier model with vascularized crypts that recapitulates relevant cytokine gradients in both healthy and inflammatory conditions. Using our previously published IFlowPlate384 platform, we initially imprinted crypt topography and populated the patterned scaffold with colon cells. Proliferative colon cells spontaneously localized to the crypt niche and differentiated into epithelial barriers with a tight brush border. Toxicity of the colon cancer drug, capecitabine, was tested and showed a dose-dependent response and recovery from crypt-patterned colon epithelium exclusively. Perfusable microvasculature was then incorporated around the colon crypts followed by treatment with pro-inflammatory TNFα and IFNγ cytokines to simulate inflammatory bowel disease (IBD)-like conditions. We observed in vivo-like stromal basal-to-apical cytokine gradients in tissues with vascularized crypts and gradient reversals upon inflammation. Taken together, we demonstrated crypt topography integrated with underlying perfusable microvasculature has significant value for emulating colon physiology and in advanced disease modelling.

Submucosal Clustered Brownish Microvessels Based on NBI Endoscopy: A Characteristic of LPR

OBJECTIVE

This study aimed to analyze the characteristics of laryngopharyngeal reflux (LPR) by using narrow band imaging (NBI) endoscopy.

STUDY DESIGN

A prospective study.

SETTING

A large-volume practice with tertiary care providers.

METHODS

A total of 67 patients with suspected LPR who underwent 24-hour multichannel intraluminal impedance-pH monitoring were included from June 2020 to March 2022. Manifestations of NBI endoscopy included submucosal clustered brownish microvessels (CBMs), spotted brownish microvessels, and no special microvessels; the latter 2 formed the non-CBM group. The manifestations of all patients and their changes were observed after 8 weeks of proton pump inhibitor and symptomatic treatment for patients with LPR, and symptomatic treatment for patients without LPR.

RESULTS

According to the results of 24-hour multichannel intraluminal impedance-pH monitoring, the incidence of submucosal CBMs was significantly higher in patients with LPR (30 cases) than in those without LPR (37 cases, P < .001), particularly in the posterior cricoid area (P < .001). Besides Reflux Finding Score, the incidence of signs such as subglottic edema and vocal fold edema was significantly higher in the CBM group than the non-CBM group (P < .05). Finally, 22 patients with LPR (91.7%) and only 2 patients without LPR (28.6%) underwent a transformation from CBMs to spotted brownish microvessels after continuous medication for 8 weeks in the CBM group (χ² = 15.916, P < .001), while no significant change was observed in patients with or without LPR in the non-CBM group (P > .05).

CONCLUSION

Submucosal CBMs in the posterior cricoid area under NBI endoscopy may be a characteristic of LPR.

LEVEL OF EVIDENCE: 4

Intravoxel incoherent motion diffusion-weighted imaging in quantitative evaluation of Ileal Crohn's disease - A comparison with dynamic contrast-enhanced magnetic resonance imaging and ileocolonoscopy

OBJECTIVES

To investigate the prospective role of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in evaluating terminal ileal Crohn's disease (CD) inflammation quantitatively, compared with quantitative dynamic contrastenhanced magnetic resonance imaging (DCE-MRI) and ileocolonoscopic segmental score.

METHODS

Fifty CD patients underwent magnetic resonance enterography (MRE) including IVIM-DWI and quantitative DCE-MRI from Jan. 2017 to Nov. 2019. ADC, D, D* and f value of IVIM-DWI and Ktrans, Kep, and Ve value of DCE-MRI in normal (n = 50) and inflamed bowel segments (n = 50), defined during the clinical MRI analysis, were calculated and compared using Wilcoxon signed-rank tests respectively. Receiver operating characteristic (ROC) analysis was performed. Correlations between IVIM-DWI and DCE-MRI parameters in comparison with ileocolonoscopic segmental score were assessed using Spearman's rank correlation analysis.

RESULTS

For IVIM-DWI, ADC, D, D* and f value showed significant differences respectively between normal and inflamed bowel segments (p < 0.05). ADC value presented the highest diagnostic accuracy (AUC = 0.813) and sensitivity (92%), and D value presented the highest specificity (84%) for the evaluation of inflamed bowel segments. For DCE-MRI, Ktrans value presented the highest diagnostic accuracy (AUC = 0.835), the highest sensitivity for Kep value (88%) and the highest specificity for Ve value (96%). ADC, f and Ktrans value had high correlations with ileocolonoscopic score respectively (r = -0.739-0.876, p < 0.01). The logarithm of normalized signal intensity/b-values for IVIM-DWI could also indicate directly the evident difference between the normal and inflamed bowel segments of terminal ileal CD.

CONCLUSION

IVIM-DWI will be another promising noninvasive tool to provide precise quantitative-indicators in evaluating inflamed bowel segments of terminal ileal CD with little contrast-agent damage worries.

Perfusion Computed Tomography May Help in Discriminating Gastrointestinal Tuberculosis and Crohn's Disease

Gastrointestinal tuberculosis (GITB) and Crohn's disease (CD) are close mimics. This prospective study aimed to evaluate the diagnostic performance of perfusion computed tomography (CT) in differentiating GITB from CD. Consecutive patients with ileocaecal thickening underwent perfusion CT of the ileocaecal region between January 2019 and July 2020. Two radiologists (blinded to the final diagnosis) independently assessed blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability at perfusion CT. These parameters were compared among the patients with GITB as well as active and inactive CD. Receiver operating characteristic curves were utilized for determining the diagnostic performance of perfusion CT. Interclass correlation coefficient and Bland-Altman analysis were performed to compare the observations of the two radiologists. During the study period, 34 patients underwent perfusion CT. Eight patients had diagnoses other than intestinal tuberculosis or CD. Thus, 26 patients (mean age 36 ± 14 years, 18 males) with GITB (n = 11), active CD (n = 6), and inactive CD (n = 9) were evaluated. BF, MTT, and permeability showed significant differences among the groups, while BV did not differ significantly among the groups. BF and permeability had 100% sensitivity and 100% specificity, while MTT had 61.5-100% sensitivity and 70-100% specificity for differentiating GITB from active CD and active from inactive CD. The interclass correlation coefficient for perfusion CT parameters was 0.88-1. Perfusion CT is a novel imaging technique that can improve the diagnostic performance of differentiating tuberculosis from CD.

Global trend and future landscape of intestinal microcirculation research from 2000 to 2021: A scientometric study

BACKGROUND

The intestinal microcirculation functions in food absorption and metabolic substance exchanges. Accumulating evidence indicates that intestinal microcirculatory dysfunction is a significant source of multiple gastrointestinal diseases. To date, there has not been a scientometric analysis of intestinal microcirculatory research.

AIM

To investigate the current status, development trends, and frontiers of intestinal microcirculatory research based on bibliometric analysis.

METHODS

VOSviewer and CiteSpace 6.1.R2 were used to identify the overall characteristics and knowledge map of intestinal microcirculatory research based on the core literature published from 2000 to 2021 in the Web of Science database. The characteristics of each article, country of origin, institution, journal, cocitations, and other information were analyzed and visualized.

RESULTS

There were 1364 publications enrolled in the bibliometric analysis, exhibiting an upward trend from 2000 to 2021 with increased participation worldwide. The United States and Dalhousie University took the lead among countries and institutions, respectively. Shock was the most prolific journal, and Nature Reviews Microbiology Clinical had the most citations. The topical hotspots and frontiers in intestinal microcirculatory research were centered on the pathological processes of functional impairment of intestinal microvessels, diverse intestinal illnesses, and clinical treatment.

CONCLUSION

Our study highlights insights into trends of the published research on the intestinal microcirculation and offers serviceable guidance to researchers by summarizing the prolific areas in intestinal disease research to date.

Diagnostic accuracy of different cross-sectional imaging techniques for disease location and activity in Crohn's disease and external validation and comparison of MARIAs and IBUS-SAS

PURPOSE

The comparative accuracy of cross-sectional imaging techniques for evaluating Crohn's disease (CD) remains uncertain. This study aimed to assess diagnostic accuracy of disease location and activity in different cross-sectional images and validate and compare International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) and Simplified Magnetic Resonance Index of Activity (MARIAs).

METHODS

CD patients were retrospectively included from August 2018 to May 2021. We compared accuracy of B-mode intestinal ultrasound (B-IUS), computed tomography enterography (CTE), and magnetic resonance enterography (MRE) for the identification of disease location. Meanwhile, disease activity was compared on B-IUS, color Doppler imaging, CTE, and MRE. ROC analyses were used to validate MARIAs and IBUS-SAS. Spearman rank correlation was performed to evaluate the relationships between MARIAs/IBUS-SAS and CDAI, SES-CD, and inflammatory indicators.

RESULTS

A total of 115 CD patients were evaluated. The diagnostic accuracy of MRE in detecting small bowel disease was superior to that of B-IUS/CTE, showing sensitivity (89.3%), specificity (71.4%), and AUC (0.820). B-IUS had the highest sensitivity (81.2%), specificity (84.8%), and AUC (0.830) for detecting terminal ileal lesions. The diagnostic accuracy for colonic disease and disease activity was not significantly different among these techniques. In the validation of IBUS-SAS, the AUC was 0.860, with an optimal cutoff value to predict active disease of 46.7. MARIAs and IBUS-SAS showed no significant differences in the correlations of CDAI, SES-CD, and inflammatory indicators.

CONCLUSION

MRE and B-IUS are more sensitive for detecting small bowel CD and terminal ileal CD, respectively. IBUS-SAS has potential for precisely defining CD activity.

The Gut-Vascular Barrier as a New Protagonist in Intestinal and Extraintestinal Diseases

The intestinal barrier, with its multiple layers, is the first line of defense between the outside world and the intestine. Its disruption, resulting in increased intestinal permeability, is a recognized pathogenic factor of intestinal and extra-intestinal diseases. The identification of a gut-vascular barrier (GVB), consisting of a structured endothelium below the epithelial layer, has led to new evidence on the etiology and management of diseases of the gut-liver axis and the gut-brain axis, with recent implications in oncology as well. The gut-brain axis is involved in several neuroinflammatory processes. In particular, the recent description of a choroid plexus vascular barrier regulating brain permeability under conditions of gut inflammation identifies the endothelium as a key regulator in maintaining tissue homeostasis and health.

Geometric engineering of organoid culture for enhanced organogenesis in a dish

Here, we introduce a facile, scalable engineering approach to enable long-term development and maturation of organoids. We have redesigned the configuration of conventional organoid culture to develop a platform that converts single injections of stem cell suspensions to radial arrays of organoids that can be maintained for extended periods without the need for passaging. Using this system, we demonstrate accelerated production of intestinal organoids with significantly enhanced structural and functional maturity, and their continuous development for over 4 weeks. Furthermore, we present a patient-derived organoid model of inflammatory bowel disease (IBD) and its interrogation using single-cell RNA sequencing to demonstrate its ability to reproduce key pathological features of IBD. Finally, we describe the extension of our approach to engineer vascularized, perfusable human enteroids, which can be used to model innate immune responses in IBD. This work provides an immediately deployable platform technology toward engineering more realistic organ-like structures in a dish.

Influence and Implications of the Molecular Paradigm of Nitric Oxide Underlying Inflammatory Reactions of the Gastrointestinal Tract of Dog: A Major Hallmark of Inflammatory Bowel Disease

Nitric oxide (NO), a pleiotropic free radical messenger molecule, is responsible for the various cellular function of the gastrointestinal mucosa. It plays a major role in the maintenance of perfusion, regulation of microvascular, epithelial permeability, and immune functions. Nitric oxide exerts its beneficial effect on the initiation and maintenance of inflammation in human inflammatory bowel disease (IBD). But the accelerated production of NO triggers activation of the inducible form of the NO synthase enzyme (iNOS) that leads to damages of the intestinal membrane. Nitric oxide synthase enzyme is responsible for the higher production of NO from l-arginine and causes an inflammatory condition in the intestinal epithelium. Nitric oxide induces nitrative DNA damage and oxidative DNA damage in the cellular system. Accelerated production of NO enhances iNOS activity that is associated with cytotoxicity and apoptosis of gastrointestinal epithelial cells in the dog. Chronic inflammation leads to angiogenesis that is modulated by the immune system in IBD. Chronic inflammation is a major risk factor for the development of gastrointestinal malignancies. Nitric oxide participates in mucosal inflammation in the intestine through invigoration of NO synthase enzyme. The intrinsic complex mechanism is correlated with the inflammation in the gastrointestinal tract and is also correlated with the expression of iNOS, enzymatic activity and NO production. Nitric oxide employs a significant role in modulating epithelial permeability with accelerated immune response in acute colitis. But the enormous generation of NO causes adverse effects on the mucosal cell during the inflammatory process in IBD. In this review, a complex episode of NO generation with altered biochemical pathways was assessed for the regulation of mucosal inflammation in inflammatory bowel disease of dogs. This review is a unique compilation of the role of NO in the pathogenesis of inflammatory bowel disease of dogs. Nitric oxide plays a key role in modulating cancer in the gastrointestinal tract. This review seeks to explore the characteristics of NO as a major hallmark of canine inflammatory bowel diseases.

Mesenchymal stem cells have ameliorative effect on the colitis model via Nrf2/HO-1 pathway

Purpose:

To evaluate the ameliorative effect of mesenchymal stem cells (MSCs) on acetic acid colitis model via Nrf2/HO-1 pathway in rats.

Methods:

In this study, 30 rats were divided into three groups. Acute colitis was induced by rectal administration of 4% solution of acetic acid. MSCs were injected intraperitoneally in the treatment group.

Results:

Increased levels of tumor necrosis factor-α (TNF-α), pentraxin-3, and malondialdehyde (MDA) in colitis group were revealed biochemically. Increased level of TNF-α and decreased levels of Nrf2 and interleukin-10 (IL-10) were observed in rectum tissues. Increased fibrous tissue proliferation, vascularization and inflammatory cell infiltration were described in the colitis group. Significant improvement was observed in MSCs treated group histopathologically. Increased immunopositivity of TNF-α, vascular endothelial growth factor (VEGF) and CD68 markers was observed in the colitis group cells, and decreased level of this positivity was observed in MSCs treated group.

Conclusions:

Biochemical, histopathological and immunohistochemical results strongly support the ameliorative effect of MSCs against acetic induced colitis model via Nrf2/HO-1 pathway in rats.

Hyaluronan: A Neuroimmune Modulator in the Microbiota-Gut Axis

The commensal microbiota plays a fundamental role in maintaining host gut homeostasis by controlling several metabolic, neuronal and immune functions. Conversely, changes in the gut microenvironment may alter the saprophytic microbial community and function, hampering the positive relationship with the host. In this bidirectional interplay between the gut microbiota and the host, hyaluronan (HA), an unbranched glycosaminoglycan component of the extracellular matrix, has a multifaceted role. HA is fundamental for bacterial metabolism and influences bacterial adhesiveness to the mucosal layer and diffusion across the epithelial barrier. In the host, HA may be produced and distributed in different cellular components within the gut microenvironment, playing a role in the modulation of immune and neuronal responses. This review covers the more recent studies highlighting the relevance of HA as a putative modulator of the communication between luminal bacteria and the host gut neuro-immune axis both in health and disease conditions, such as inflammatory bowel disease and ischemia/reperfusion injury.

AHR in the intestinal microenvironment: safeguarding barrier function

Mammalian aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that belongs to the basic helix-loop-helix (bHLH)-PAS family of transcription factors, which are evolutionarily conserved environmental sensors. In the absence of ligands, AHR resides in the cytoplasm in a complex with molecular chaperones such as HSP90, XAP2 and p23. Upon ligand binding, AHR translocates into the nuclear compartment, where it dimerizes with its partner protein, AHR nuclear translocator (ARNT), an obligatory partner for the DNA-binding and functional activity. Historically, AHR had mostly been considered as a key intermediary for the detrimental effects of environmental pollutants on the body. However, following the discovery of AHR-mediated functions in various immune cells, as well as the emergence of non-toxic 'natural' AHR ligands, this view slowly began to change, and the study of AHR-deficient mice revealed a plethora of important beneficial functions linked to AHR activation. This Review focuses on regulation of the AHR pathway and the barrier-protective roles AHR has in haematopoietic, as well as non-haematopoietic, cells within the intestinal microenvironment. It covers the nature of AHR ligands and feedback regulation of the AHR pathway, outlining the currently known physiological functions in immune, epithelial, endothelial and neuronal cells of the intestine.

Role of sphingosine-1-phosphate receptors in vascular injury of inflammatory bowel disease

Sphingosine‐1‐phosphate receptors (S1PRs) have an impact on the intestinal inflammation of inflammatory bowel disease (IBD) by regulating lymphocyte migration and differentiation. S1PR modulators as an emerging therapeutic approach are being investigated for the treatment of IBD. However, the role of S1PRs in intestinal vessels has not drawn much attention. Intestinal vascular damage is one of the major pathophysiological features of IBD, characterized by increased vascular density and impaired barrier function. S1PRs have pleiotropic effects on vascular endothelial cells, including proliferation, migration, angiogenesis and barrier homeostasis. Mounting evidence shows that S1PRs are abnormally expressed on intestinal vascular endothelial cells in IBD. Unexpectedly, S1PR modulators may damage intestinal vasculature, for example increase intestinal bleeding; therefore, S1PRs are thought to be involved in the regulation of intestinal vascular function in IBD. However, little is understood about how S1PRs regulate intestinal vascular function and participate in the initiation and progression of IBD. In this review, we summarize the pathogenic role of S1PRs in and the underlying mechanisms behind the intestinal vascular injury in IBD in order for improving IBD practice including S1PR‐targeted therapies.

Proteinuria Is Associated with the Development of Crohn's Disease: A Nationwide Population-Based Study

BACKGROUND AND AIMS

The impact of proteinuria and its severity on the incidence of inflammatory bowel disease (IBD) has not yet been studied. We aimed to determine the association between proteinuria measured by urine dipstick tests and the development of IBD.

METHODS

This nationwide population-based study was conducted using the Korean National Health Insurance Service (NHIS) database. A total of 9,917,400 people aged 20 years or older who had undergone a national health examination conducted by the NHIS in 2009 were followed up until 2017. The study population was classified into four groups-negative, trace, 1+, and ≥ 2+-according to the degree of proteinuria measured by the urine dipstick test. The primary endpoint was newly diagnosed IBD, Crohn's disease (CD), or ulcerative colitis (UC) during the follow-up period.

RESULTS

Compared with the dipstick-negative group, the incidence of CD significantly increased according to the degree of proteinuria (adjusted hazard ratio [aHR] with 95% confidence interval [CI], 1.01 [0.703-1.451], 1.515 [1.058-2.162], and 2.053 [1.301-3.24] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.007). However, there was no significant difference in the incidence of UC according to the degree of proteinuria (aHR with 95% CI, 1.12 [0.949-1.323], 0.947 [0.764-1.174], and 1.009 [0.741-1.373] in the trace, 1+, and ≥ 2+ dipstick groups, respectively; p for trend 0.722). In the subgroup analysis, dipstick-positive proteinuria independently increased the incidence of CD regardless of the subgroup. However, dipstick-positive proteinuria was associated with the risk of UC in those with diabetes mellitus and not in those without diabetes mellitus (aHR, 1.527 vs. 0.846; interaction p-value 0.004). The risk of CD was increased or decreased according to proteinuria changes but not associated with the risk of UC.

CONCLUSION

Proteinuria, measured by the dipstick test, is strongly associated with the development of CD.

Color Doppler Ultrasound Assessment of Clinical Activity in Inflammatory Bowel Disease

BACKGROUND

Ulcerative colitis (UC) and Crohn's disease (CD) are two varieties of inflammatory bowel disease (IBD). Clinicians need a monitoring technique in the IBD. The disease activity can be assessed with endoscopy, activity indexes, and imaging techniques. Color Doppler US (CDUS) is also a non-invasive, radiation, and contrast material free examination which shows the intramural blood flow.

OBJECTIVE

To evaluate the usefulness of B-mode, CDUS, and a newly developed software Color Quantification (CQ) to determine the activity of the IBD.

METHODS

The disease activity was assessed by clinical activity indexes. Caecum, terminal ileum, ascending colon, transverse colon, and descending colon were evaluated by B-mode, CDUS, and the CQ. Bowel wall thickness (BWT), loss of bowel stratification, loss of haustration, and the presence of enlarged lymph nodes, mesenteric masses, abscesses, fistula, visual vascular signal patterns of the bowel as "hypo and hyper-flow" and the CQ values were investigated. BWT was compared with laboratory results and clinical activities. Vascular signal patterns and the CQ values were compared with BWT and clinical activity. The diagnostic performances of the CQ were investigated.

RESULTS

Fifty-two patients with IBD were evaluated. Patients with increased BWT at the transverse colon had an increased frequency of "hyper-flow" pattern. Clinically active patients had an increased incidence of "hyper-flow" pattern at the terminal ileum, ascending colon, and whole segments. They had increased CQ values at the terminal ileum, ascending colon, and descending colon, and whole segments. A cut-off value for the CQ (24.7%) was obtained at the terminal ileum. In the diagnostic performances of CQ, we observed utilities significantly at the ascending colon, descending colon, terminal ileum, and whole segments. There was a positive correlation between the CQ values and BWT at the caecum, ascending colon, transverse colon, and descending colon.

CONCLUSION

Increased visual vascular signal scores and CQ values might be useful for monitoring the disease activity in patients with IBD.

Thalidomide Inhibits Angiogenesis via Downregulation of VEGF and Angiopoietin-2 in Crohn's Disease

Immune-mediated angiogenesis is important in the pathogenesis of inflammatory bowel disease and targeted treatment could alleviate the disease. Thalidomide is an effective drug in inflammatory bowel disease, which might be related to its multiple role in anti-inflammatory, immunoregulatory, and anti-angiogenesis. This study is to investigate the effect of thalidomide on angiogenesis in tissues from patients and in vitro cells. Angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), VEGF, and CD31 expressions in intestinal mucosa from pediatric CD patients before and after thalidomide treatment were measured by immunohistochemistry. Western blotting and polymerase chain reaction were performed to characterize the change of angiogenic factors before and after treatment in remission. Human umbilical vein endothelial cells (HUVECs) treated by thalidomide were used to examine its effect on endothelial cell proliferation and migration and capillary-like structures. Results showed that VEGF and Ang-2 levels were significantly greater in CD patients over controls. Thalidomide produced a significant reduction in protein expression of Ang-2 and VEGF, along with a decrease in mRNA expression of Ang-2. While, Ang-1 level did not show a statistically significant change. Thalidomide significantly inhibited cell proliferation in a dose-dependent manner. It also suppressed VEGF- and Ang-2-induced cell migration and capillary-like tube formation in HUVECs. Therefore, our study suggests that VEGF and Ang-2 levels are up-regulated in pediatric CD patients. It also indicated that thalidomide can be able to deactivate endothelium by the downregulation effect on angiogenic factors by targeting VEGF and Ang-2.

Dynamic contrast-enhanced magnetic resonance imaging and diffusion-weighted imaging in the activity staging of terminal ileum Crohn's disease

BACKGROUND

The activity staging of Crohn’s disease (CD) in the terminal ileum is critical in developing an accurate clinical treatment plan. The activity of terminal ileum CD is associated with the microcirculation of involved bowel walls. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) can reflect perfusion and permeability of bowel walls by providing microcirculation information. As such, we hypothesize that DCE-MRI and DWI parameters can assess terminal ileum CD, thereby providing an opportunity to stage CD activity.

AIM

To evaluate the value of DCE-MRI and DWI in assessing activity of terminal ileum CD.

METHODS

Forty-eight patients with CD who underwent DCE-MRI and DWI were enrolled. The patients’ activity was graded as remission, mild and moderate-severe. The transfer constant (K^trans), wash-out constant (K_ep), and extravascular extracellular volume fraction (V_e) were calculated from DCE-MRI and the apparent diffusion coefficient (ADC) was obtained from DWI. Magnetic Resonance Index of Activity (MaRIA) was calculated from magnetic resonance enterography. Differences in these quantitative parameters were compared between normal ileal loop (NIL) and inflamed terminal ileum (ITI) and among different activity grades. The correlations between these parameters, MaRIA, the Crohn’s Disease Activity Index (CDAI), and Crohn’s Disease Endoscopic Index of Severity (CDEIS) were examined. Receiver operating characteristic curve analyses were used to determine the diagnostic performance of these parameters in differentiating between CD activity levels.

RESULTS

Higher K^trans (0.07 ± 0.04 vs 0.01 ± 0.01), K_ep (0.24 ± 0.11 vs 0.15 ± 0.05) and V_e (0.27 ± 0.07 vs 0.08 ± 0.03), but lower ADC (1.41 ± 0.26 vs 2.41 ± 0.30) values were found in ITI than in NIL (all P < 0.001). The K^trans, K_ep, V_e and MaRIA increased with disease activity, whereas the ADC decreased (all P < 0.001). The K^trans, K_ep, V_e and MaRIA showed positive correlations with the CDAI (r = 0.866 for K^trans, 0.870 for K_ep, 0.858 for V_e, 0.890 for MaRIA, all P < 0.001) and CDEIS (r = 0.563 for K^trans, 0.567 for K_ep, 0.571 for V_e, 0.842 for MaRIA, all P < 0.001), while the ADC showed negative correlations with the CDAI (r = -0.857, P < 0.001) and CDEIS (r = -0.536, P < 0.001). The areas under the curve (AUC) for the K^trans, K_ep, V_e, ADC and MaRIA values ranged from 0.68 to 0.91 for differentiating inactive CD (CD remission) from active CD (mild to severe CD). The AUC when combining the K^trans, K_ep and V_e was 0.80, while combining DCE-MRI parameters and ADC values yielded the highest AUC of 0.95.

CONCLUSION

DCE-MRI and DWI parameters all serve as measures to stage CD activity. When they are combined, the assessment performance is improved and better than MaRIA.

Magnetic resonance enterography perfusion parameters reveal complex changes in affected and unaffected segments in Crohn's disease

OBJECTIVES

To compare dynamic contrast-enhanced (DCE)-MRI parameters in affected and unaffected segments of CD patients with those of a control group, and to assess the correlation between DCE-MRI parameters and clinical index of activity (HBI) as well as biomarkers (CRP and faecal calprotectin).

METHODS

We performed a single-center prospective study of CD patients and control subjects who underwent DCE-MRI. Regions of interest were drawn in segments and the program (Olea Medical - Canon) provided values for transfer constant (Ktrans), fractional volume of extravascular-extracellular space (Ve), slope of enhancement (SoE), time to maximum enhancement (TME), maximum enhancement (ME) and enhancement ratio (ER) which were determined and compared.

RESULTS

Fifteen CD patients (mean age 42 years; 10 women) and 7 healthy subjects (mean age 40.4 years; 6 women) were included. Paired comparisons of affected and unaffected segments in CD showed a significant increase of all parameters in affected segments, except for ER and TME. When comparing to controls, the affected segments did not show any significant difference, while a significant decrease in most of the parameters (except for ER and TME) was observed when comparing unaffected segments of CD patients to controls. In CD, significant correlations between DCE-MRI parameters and biomarkers (CRP, faecal calprotectin) were more frequent in unaffected segments than in affected segments.

CONCLUSIONS

Significant differences in perfusion parameters were observed between affected and unaffected segments of CD patients and between unaffected segments and those of control subjects. This suggests complex perfusion changes in both unaffected and affected intestinal segments in CD.

Experimental and Clinical Evidence of Endothelial Dysfunction in Inflammatory Bowel Disease

The endothelium has a crucial role in proper hemodynamics. Inflammatory bowel disease (IBD) is mainly a chronic inflammatory condition of the gastrointestinal tract. However, considerable evidence points to high cardiovascular risk in patients with IBD. This review positions the basic mechanisms of endothelial dysfunction in the IBD setting (both clinical and experimental). Furthermore, we review the main effects of drugs used to treat IBD in endothelial (dys)function. Moreover, we leave challenging points for enlarging the therapeutic arsenal for IBD with new or repurposed drugs that target endothelial dysfunction besides inflammation.

Quantitative evaluation of Crohn's disease using dynamic contrast-enhanced MRI in children and young adults

OBJECTIVES

To evaluate the clinical usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in children and young adults with Crohn's disease.

METHODS

From August 2017 to October 2018, 30 patients with Crohn's disease (21 males and 9 females; mean age 15.1 ± 2.5 years) underwent DCE-MRI with MRI enterography. We assessed the endoscopic finding, pediatric Crohn's disease activity index (PCDAI), C-reactive protein (CRP) level (mg/dL), Crohn's disease MR index (CDMI) score, and the perfusion parameters of DCE-MRI (K^trans, K^ep, and V^e) at the ileocecal region between the inactive and active groups based on the histopathologic status.

RESULTS

The active Crohn's disease group showed higher PCDAI, CRP, and CDMI scores than the inactive group (22.2 ± 18.8 vs. 6.3 ± 6.4, p = 0.027; 1.32 ± 1.79 vs. 0.10 ± 0.13, p = 0.005; 7.4 ± 3.9 vs. 4.5 ± 3.0, p = 0.047, respectively). The active Crohn's disease group showed a higher K^trans value than the inactive group (0.31  ±  0.12 vs. 0.16 ±  0.46 min^-1, p = 0.002). Endoscopic finding; PCDAI, CRP, and CDMI scores; and K^trans value were significant parameters in the identification of the active Crohn's disease (p = 0.002, p < 0.001, p = 0.029, p = 0.006, and p < 0.001, respectively). K^trans value was the most significant value for identifying active Crohn's disease in the multivariate logistic regression analysis (p = 0.013).

CONCLUSION

K^trans value could discriminate between inactive and active Crohn's diseases. K^trans value may have the potential to monitor the pediatric Crohn's disease activity.

KEY POINTS

• With dynamic contrast-enhanced MRI, we can quantitatively monitor the Crohn's disease status in pediatric patients and provide proper management plans to clinicians. • The K^transvalue of dynamic contrast-enhanced MRI perfusion parameter, as well as the clinical pediatric Crohn's disease activity index, C-reactive protein level, the endoscopic score, and the Crohn's disease MR index, was higher in the active Crohn's disease than in the inactive group based on the histopathologic status. • The K^transvalue among the dynamic contrast-enhanced MRI perfusion parameters was the most significant differentiating parameter for the active Crohn's disease from inactive status among those parameters (p = 0.013).

Associations between quantitative evaluation of bowel wall microvascular flow by contrast-enhanced ultrasound and indices of disease activity in Crohn's disease patients using both bolus and infusion techniques

PURPOSE

The aim is to investigate whether baseline contrast-enhanced ultrasound (CEUS) correlates with indices of activity in Crohn's disease (CD) and can predict response to medical treatment.

METHODS

In this prospective study, symptomatic CD patients underwent baseline CEUS performed with Definity using both bolus and infusion methods. Time-intensity curves (TIC), peak intensity (PI), and area under curve (AUC) from a region of interest over the diseased bowel were calculated for both bolus and infusion acquisitions. We used Mann-Whitney U test for continuous and chi-square/two-tailed Fisher's exact test for categorical variable comparison and Spearman's correlation coefficient to correlate clinical score and CEUS kinetic parameters.

RESULTS

Twenty-one patients (9 men, 12 women, median age 32 years) were accrued. Fifteen patients had clinically active disease defined as Harvey-Bradshaw Index (HBI) score ≥5. Median values of baseline CEUS parameters PI (bolus: 26 vs 8.86; P = .023 and perfusion: 7.6 vs 3.2; P = .009) and AUC (bolus: 769 vs 248.8; P = .036 and perfusion: 188.9 vs 73.9; P = .012) differed significantly in patients with active vs inactive disease. Nine patients with active disease underwent escalated or new treatment. Five were nonresponders. Responders had higher median values of baseline parameters (PI, bolus: 35 vs 18.8; P = .556, and perfusion: 7.6 vs 3.9; P = 190), (AUC, bolus: 1473.9 vs 314; P = .111, and perfusion: 154.7 vs 74.4, P = .286).

CONCLUSIONS

CEUS kinetic parameters correlate with clinical and laboratory indices and are significantly higher in patients with active disease. The responders had higher CEUS kinetic parameters than nonresponders that did not reach statistical significance in our small cohort.

Roles of Nicotine in the Development of Intracranial Aneurysm Rupture

Background and Purpose- Tobacco cigarette smoking is considered to be a strong risk factor for intracranial aneurysmal rupture. Nicotine is a major biologically active constituent of tobacco products. Nicotine's interactions with vascular cell nicotinic acetylcholine receptors containing α7 subunits (α7*-nAChR) are thought to promote local inflammation and sustained angiogenesis. In this study, using a mouse intracranial aneurysm model, we assessed potential contributions of nicotine exposure and activation of α7*-nAChR to the development of aneurysmal rupture. Methods- Intracranial aneurysms were induced by a combination of deoxycorticosterone-salt induced hypertension and a single-dose elastase injection into cerebrospinal fluid in mice. Results- Exposure to nicotine or an α7*-nAChR-selective agonist significantly increased aneurysm rupture rate. Coexposure to an α7*-nAChR antagonist abolished nicotine's deleterious effect. In addition, nicotine's promotion of aneurysm rupture was absent in smooth muscle cell-specific α7*-nAChR subunit knockout mice but not in mice lacking α7*-nAChR on endothelial cells or macrophages. Nicotine treatment increased the mRNA levels of vascular endothelial growth factor, platelet-derived growth factor-B, and inflammatory cytokines. α7*-nAChR antagonist reversed nicotine-induced upregulation of these growth factors and cytokines. Conclusions- Our findings indicate that nicotine exposure promotes aneurysmal rupture through actions on vascular smooth muscle cell α7*-nAChR.

Beneficial effects of nutritional supplements on intestinal epithelial barrier functions in experimental colitis models in vivo

Acute and chronic colitis affect a huge proportion of the population world-wide. The etiology of colitis cases can be manifold, and diet can significantly affect onset and outcome of colitis. While many forms of acute colitis are easily treatable, chronic forms of colitis such as ulcerative colitis and Crohn's disease (summarized as inflammatory bowel diseases) are multifactorial with poorly understood pathogenesis. Inflammatory bowel diseases are characterized by exacerbated immune responses causing epithelial dysfunction and bacterial translocation. There is no cure and therapies aim at reducing inflammation and restoring intestinal barrier function. Unfortunately, most drugs can have severe side effects. Changes in diet and inclusion of nutritional supplements have been extensively studied in cell culture and animal models, and some supplements have shown promising results in clinical studies. Most of these nutritional supplements including vitamins, fatty acids and phytochemicals reduce oxidative stress and inflammation and have shown beneficial effects during experimental colitis in rodents induced by dextran sulphate sodium or 2,4,6-trinitrobenzene sulfonic acid, which remain the gold standard in pre-clinical colitis research. Here, we summarize the mechanisms through which such nutritional supplements contribute to epithelial barrier stabilization.

Magnification endoscopy with optical chromoendoscopy shows strong correlation with histologic inflammation in patients with inflammatory bowel disease

Background and study aims  Apart from mucosal healing as an established treatment goal in inflammatory bowel diseases (IBD), recent evidence suggests that histologic healing may become another key prognostic parameter in IBD patients. We aimed to evaluate whether magnification endoscopy with optical chromoendoscopy can accurately assess histologic inflammation in IBD patients. Patients and methods  In this prospective study, 82 patients with IBD (30 UC, 52 CD) were included. In all patients, magnification endoscopy in conjunction with optical chromoendoscopy was performed and rated on a novel magnification endoscopy score by three independent endoscopists. Targeted biopsies of the imaged areas were obtained and results were compared against two histological scores in UC (Robarts Histopathology Index, RHI; Nancy Histology Index, NHI) and one score in CD (modified Riley index, mRI). Moreover, interobserver agreement was calculated. Results  Magnification endoscopy showed strong correlation with histopathologic scoring in both UC (RHI: r = 0.83, NHI: r = 0.78, P  < 0.05) and CD (mRI: r = 0.74, P  < 0.05) with high accuracy, sensitivity, and specificity. Further, 25 % of patients with mucosal healing on standard endoscopy showed signs of microinflammation on magnification endoscopy with optical chromoendoscopy, while none of the patients with mucosal and vascular healing under magnification endoscopy with optical chromoendoscopy exhibited microscopic inflammation. Interobserver agreement for grading intestinal inflammation by magnification endoscopy with optical chromoendoscopy was substantial (κ > 0.7). Conclusion  Magnification endoscopy in combination with optical chromoendoscopy shows strong correlation with histologic inflammation in patients with IBD. This approach has potential to reduce physical biopsies for monitoring of inflammatory activity in patients with IBD during colonoscopy.

Imbalanced mucosal microcirculation in the remission stage of ulcerative colitis using probe-based confocal laser endomicroscopy

Background

Microcirculatory disturbance is an important factor in the pathogenesis of Inflammatory Bowel Disease (IBD) but there have been few studies in this field. Confocal Laser Endomicroscopy (CLE) has been used over the last 10 years and has made it possible to explore the changes in microcirculation of the colonic mucosa.

Methods

We retrospectively selected patients who underwent probe-based Confocal Laser Endomicroscopy (pCLE) between 2014 and 2016. There were 7 patients with ulcerative colitis (UC) in clinical remission and 7 healthy subjects included in this study; all the UC patients’ medical data were reviewed. For each patient, three segments of the colon were examined using pCLE including the ascending, transverse/descending and sigmoid colon. In each segment, the representative pCLE images of the three sites were selected for analysis. Four indicators, including Mean Vessel Diameter (MVD), Diameter Standard Deviation (DSD), Functional Capillary Density-long (FCDL) and Functional Capillary Density-area (FCDA), were measured with a specially designed detection software algorithm. The four indicators were compared between UC patients and healthy subjects. According to the different blood flow patterns, three types of distribution were established: the Around (A), Cobweb (C) and Deficiency (D) type. The relationships between the recurrence and blood flow patterns of UC patients were analyzed.

Results

MVD, DSD, FCDL and FCDA were 10.62 ± 0.56 μm, 2.23 ± 0.26, 0.030 ± 0.019 μm and 0.289 ± 0.030 for the healthy subjects and 11.06 ± 1.10 μm, 2.68 ± 0.29, 0.026 ± 0.005 μm and 0.272 ± 0.034 for the UC patients, respectively. Compared with healthy subjects, DSD was significantly increased and FCDA was significantly decreased (P < 0.01 for both). There was no difference in MVD and FCDL between UC patients and healthy subjects. The type A and type C blood flows were observed in healthy subjects (66.67 and 33.33%, respectively) while type C appears more in UC patients (71.3%) and type D blood flow could only be found in UC patients (14.29%) P < 0.01. UC patients who showed Type D blood flow had a shorter recurrence interval.

Conclusions

Some local mucosal capillary density in UC patients was decreased, particularly in the inflammation-affected segment. The three mucosal blood flow patterns can be used as an indicator of mucosal healing.

Hyaluronan in inflammatory bowel disease: Cross-linking inflammation and coagulation

Hyaluronan, a major extracellular matrix component, is an active participant in many disease states, including inflammatory bowel disease (IBD). The synthesis of this dynamic polymer is increased at sites of inflammation. Hyaluronan together with the enzymes responsible for its synthesis, degradation, and its binding proteins, directly modulates the promotion and resolution of disease by controlling recruitment of immune cells, by release of inflammatory cytokines, and by balancing hemostasis. This review discusses the functional significance of hyaluronan in the cells and tissues involved in inflammatory bowel disease pathobiology.

Measurement of Microvascular Function in Pediatric Inflammatory Bowel Disease

BACKGROUND AND AIMS

Altered vascular flow is known to both play a role in the pathogenesis and influence the severity of inflammatory bowel disease (IBD). This phenomenon has been described in other systemic conditions and contributes to disease progression by facilitating inflammation and thrombosis. Microvascular dysfunction may represent an early sign of generalized vascular disease (VD). It manifests by failure to achieve a normal response of vasodilation and increased blood flow following a period of vaso-occlusion. Although thromboembolic complications are well described in IBD, their pathogenesis is not fully understood. This study sought to assess microvascular responsiveness in pediatric subjects with IBD, by recording postocclusion peripheral arterial pulsatile volume changes.

PATIENTS AND METHODS

A total of 32 pediatric subjects were studied, including 16 with IBD and 16 age-matched controls. All patients with IBD were in clinical remission, and none had known VD. Vascular reactivity was evaluated using the Itamar Medical EndoPAT2000, a noninvasive device utilizing plethysmography to measure microvascular flow. Results were reported as the reactive hyperemia index (RHI), indicating post- to preocclusion pulsatile volume changes.

RESULTS

Baseline characteristics, including body mass index, plasma lipid levels, hemoglobin, and serum albumin, were similar in both study groups. All patients with IBD were in clinical remission, assessed by standard disease activity scoring methods. Measurements of microvascular function indicated patients with IBD exhibited a mean RHI both within the range associated with VD risk in adults (≤1.67) and significantly lower than that in controls (IBD vs control = 1.66 vs 2.02, P = 0.036).

CONCLUSIONS

Microvascular plethysmography is a safe and noninvasive method for assessing microvascular function in children with IBD. Patients with IBD in clinical remission demonstrate an attenuated, postocclusion microvascular hyperemic response, compared with the normal response in controls. These findings suggest pediatric IBD subjects with a mean RHI within the VD "at risk" range should be monitored for thromboembolic phenomena. Further studies in a larger patient population and over longer periods should be conducted to validate our findings and to determine the importance of these measurements in guiding IBD management.

The Long Pentraxin PTX3 as a Humoral Innate Immunity Functional Player and Biomarker of Infections and Sepsis

The first line of defense in innate immunity is provided by cellular and humoral mediators. Pentraxins are a superfamily of phylogenetically conserved humoral mediators of innate immunity. PTX3, the first long pentraxin identified, is a soluble pattern recognition molecule rapidly produced by several cell types in response to primary pro-inflammatory signals and microbial recognition. PTX3 acts as an important mediator of innate immunity against pathogens of fungal, bacterial and viral origin, and as a regulator of inflammation, by modulating complement activation and cell extravasation, and facilitating pathogen recognition by myeloid cells. In sepsis, PTX3 plasma levels are associated with severity of the condition, patient survival, and response to therapy. In combination with other established biomarkers, PTX3 could improve stratification of sepsis patients and thus, complement the system of classification and monitoring of this disease.

Papaverine adjuvant therapy for microcirculatory disturbance in severe ulcerative colitis complicated with CMV infection: a case report

Ulcerative colitis has hypercoagulable state and high risk of thrombosis; so mucosal disturbance of microcirculation may be mediate and amplify the inflammation of ulcerative colitis. A 56-year-old female patient was admitted in hospital for discontinuously mucous bloody stool for more than 1 year. Ulcerative colitis was determined after colonoscopy and pathologic examination. Mesalazine was effective during the year, but her symptoms recurred three times due to her bad compliance. One month before admission, the patient had severe recurrence after mesalazine withdrawal. At this time, the result of quantitative fluorescence PCR of colonic histic CMV-DNA was 1.6 × 10⁴ copies/mL positive, CMV colitis was accompanied. After 4 weeks of ganciclovir and 6 weeks of mesalazine usage and nutrition support, the symptoms of diarrhea and abdominal cramp did not improve; stool frequency was more than twenty times a day. Probe-based confocal laser endomicroscopy revealed local microcirculation disturbance. Papaverine 90-mg slow drip for at least 10 h a day was added. The symptoms dramatically disappeared after 3 days of papaverine treatment. The patient had yellow mushy stool 2–3 times a day. Pathological findings showed diffuse submucosal hemorrhage and transparent thrombosis in capillaries. Treatment of microcirculatory disturbance in severe UC is a promising adjuvant therapy. Confocal laser endomicroscopy may be an effective method for microcirculation judgment.

Narrow-Band Imaging Colonoscopy to Assess Mucosal Angiogenesis in Ulcerative Colitis

Background and Aim

It has been documented that angiogenesis is a largely unstudied component of the pathogenesis of ulcerative colitis (UC). Under narrow-band imaging (NBI) colonoscopy, the mucosal vascular pattern (MVP) can be visualized without the use of dyes. The aim of this study was to assess the grade of mucosal angiogenesis based on the MVP in UC.

Methods

A total of 119 colorectal segments taken from 42 patients with UC were observed using NBI colonoscopy. The MVP was classified as follows: clear, obscure, or absent. Quantification of the degree of inflammation was performed using histological colitis scoring. Potent angiogenic activity was assessed by immunohistochemical staining for vascular endothelial growth factor (VEGF). Microvascular density was assessed using vessel counts as revealed by CD31 staining. The correlation between the MVP and histological grades of inflammation and angiogenesis was evaluated.

Results

The MVP correlated well with the histological severity of inflammation. We also demonstrated an increasing level of microvascular density and VEGF staining along with the ordered types of MVPs. In addition, a statistically strong association existed between microvascular density and VEGF staining.

Conclusions

NBI colonoscopy might be a useful tool for the in vivo assessment of the grade of mucosal angiogenesis in UC.

Diagnostic and Predictive Value of Using RGD PET/CT in Patients with Cancer: A Systematic Review and Meta-Analysis

The purpose of this study was to assess the diagnostic value of arginine-glycine-aspartic acid (RGD) PET/CT for tumor detection in patients with suspected malignant lesions and to determine the predictive performance of RGD PET/CT in identifying responders. Methods. The PubMed (Medline), EMBASE, Cochrane Library, and Web of Science databases were systematically searched for potentially relevant publications (last updated on July 28th, 2018) reporting the performance of RGD PET in the field of oncology. Pooled sensitivities, specificities, and diagnostic odds ratios (DORs) were calculated for parameters. The areas under the curve (AUCs) and Q⁎ index scores were determined from the constructed summary receiver operating characteristic (SROC) curve. We explored heterogeneity by metaregression. Results. Nine studies, five including 216 patients that determined diagnostic performance and three including 75 patients that determined the predictive value of parameters, met our inclusion criteria. The pooled sensitivity, pooled specificity, DOR, AUC, and Q⁎ index score of RGD PET/CT for the detection of underlying malignancy were 0.85 (0.79-0.89), 0.93 (0.90-0.96), 48.35 (18.95-123.33), 0.9262 (standard error=0.0216), and 0.8606 for SUVmax and 0.86 (0.80-0.91), 0.92 (0.88-0.94), 40.49 (14.16-115.77), 0.9312 (SE=0.0177), and 0.8665 for SUVmean, respectively. The pooled sensitivity, pooled specificity, DOR, AUC, and Q⁎ index score of RGD PET/CT for identifying responders were 0.80 (0.59-0.93), 0.74 (0.60-0.85), 15.76 (4.33-57.32), 0.8682 (0.0539), and 0.7988, respectively, for SUVmax at baseline. Conclusion. The interesting but preliminary data in this meta-analysis demonstrate that RGD PET/CT may be an ideal diagnostic tool for detecting underlying malignancies in patients suspected of having tumors and may be able to efficiently predict short-term outcomes.

Clostridium difficile toxins induce VEGF-A and vascular permeability to promote disease pathogenesis

Clostridium difficile infection (CDI) is mediated by two major exotoxins, toxin A (TcdA) and toxin B (TcdB), that damage the colonic epithelial barrier and induce inflammatory responses. The function of the colonic vascular barrier during CDI has been relatively understudied. Here we report increased colonic vascular permeability in CDI mice and elevated vascular endothelial growth factor A (VEGF-A), which was induced in vivo by infection with TcdA- and/or TcdB-producing C. difficile strains but not with a TcdA^-TcdB^- isogenic mutant. TcdA or TcdB also induced the expression of VEGF-A in human colonic mucosal biopsies. Hypoxia-inducible factor signalling appeared to mediate toxin-induced VEGF production in colonocytes, which can further stimulate human intestinal microvascular endothelial cells. Both neutralization of VEGF-A and inhibition of its signalling pathway attenuated CDI in vivo. Compared to healthy controls, CDI patients had significantly higher serum VEGF-A that subsequently decreased after treatment. Our findings indicate critical roles for toxin-induced VEGF-A and colonic vascular permeability in CDI pathogenesis and may also point to the pathophysiological significance of the gut vascular barrier in response to virulence factors of enteric pathogens. As an alternative to pathogen-targeted therapy, this study may enable new host-directed therapeutic approaches for severe, refractory CDI.

Persistent Enhancement on Contrast-Enhanced Ultrasound Studies of Severe Crohn's Disease: Stuck Bubbles?

A small population of patients with severe Crohn's disease (CD) exhibit atypical lack of intensity decline on intestinal contrast-enhanced ultrasound. From a retrospective CD cohort examined with contrast-enhanced ultrasound, 104 patients were identified. Twenty study patients with severe active disease exhibited high peak enhancement (>23 dB) and minimal decline. From the same cohort, 84 control patients also exhibited high peak enhancement >23dB, but with typical intensity decline. Patient outcomes were assessed. Time-intensity curve analysis revealed a significantly higher (p < 0.0001) area under the curve (44.7 ± 1.5 dB·s), washout time and intensities at 60s and 120s in the study population compared with controls (40.0 ± 1.1 dB·s). Study patients had a worse overall outcome with surgery in 30% versus 10% (p = 0.027) during follow-up. Heightened enhancement with lack of decline on contrast-enhanced ultrasound suggests microbubbles are stuck within the inflamed bowel wall for an extended period. This observation occurs in patients with severe disease and a bad outcome.

[TRPV4 regulates vascular endothelial permeability during colonic inflammation in dextran sulphate sodium-induced murine colitis]

The transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel involved in physical sensing in various tissue types. The present study aimed to elucidate the function and expression of TRPV4 in colonic vascular endothelial cells during dextran sulphate sodium (DSS)-induced colitis. The role of TRPV4 in the progression of colonic inflammation was examined in the 2% DSS-induced murine colitis model using immunohistochemical analysis, Western blotting, and Evans blue dye extrusion assay. DSS-induced colitis was significantly attenuated in TRPV4-deficient (TRPV4 KO) mice when compared to wild-type mice. Repeated intrarectal administration of GSK1016790A, a TRPV4 agonist, exacerbated the severity of DSS-induced colitis. Bone marrow transfer experiments demonstrated a dominant role of TRPV4 in non-haematopoietic cells for DSS-induced colitis. DSS treatment upregulated TRPV4 expression in the vascular endothelia of colonic mucosa and submucosa. DSS treatment increased vascular permeability, which was abolished in TRPV4 KO mice. The DSS-induced increase in vascular permeability was further enhanced by intravenous administration of GSK1016790A, which was abrogated by a TRPV4 antagonist RN1734. TRPV4 was co-localized with vascular endothelial (VE)-cadherin, and VE-cadherin expression was decreased by repeated intravenous administration of GSK1016790A during colitis. Furthermore, TRPV4 activation by GSK106790A decreased VE-cadherin expression in mouse aortic endothelial cells exposed to TNF-α. These findings indicate that TRPV4 upregulation in vascular endothelial cells contributes to the progression of colonic inflammation via the activation of vascular permeability. Thus, TRPV4 is an attractive target for the treatment of inflammatory bowel diseases.