Crohn's disease: A retrospective analysis between computed tomography enterography, colonoscopy, and histopathology

Mycobacterium avium paratuberculosis Infection Suppresses Vitamin D Activation and Cathelicidin Production in Macrophages through Modulation of the TLR2-Dependent p38/MAPK-CYP27B1-VDR-CAMP Axis

BACKGROUND

Vitamin D plays a vital role in modulating both innate and adaptive immune systems. Therefore, vitamin D deficiency has been associated with higher levels of autoimmune response and increased susceptibility to infections. CYP27B1 encodes a member of the cytochrome P450 superfamily of enzymes. It is instrumental in the conversion of circulating vitamin D (calcifediol) to active vitamin D (calcitriol). This is a crucial step for macrophages to express Cathelicidin Anti-microbial Peptide (CAMP), an anti-bacterial factor released during the immune response. Our recent study indicated that a Crohn's disease (CD)-associated pathogen known as Mycobacterium avium paratuberculosis (MAP) decreases vitamin D activation in macrophages, thereby impeding cathelicidin production and MAP infection clearance. The mechanism by which MAP infection exerts these effects on the vitamin D metabolic axis remains elusive.

METHODS

We used two cell culture models of THP-1 macrophages and Caco-2 monolayers to establish the effects of MAP infection on the vitamin D metabolic axis. We also tested the effects of Calcifediol, Calcitriol, and SB203580 treatments on the relative expression of the vitamin D metabolic genes, oxidative stress biomarkers, and inflammatory cytokines profile.

RESULTS

In this study, we found that MAP infection interferes with vitamin D activation inside THP-1 macrophages by reducing levels of CYP27B1 and vitamin D receptor (VDR) gene expression via interaction with the TLR2-dependent p38/MAPK pathway. MAP infection exerts its effects in a time-dependent manner, with the maximal inhibition observed at 24 h post-infection. We also demonstrated the necessity to have toll-like receptor 2 (TLR2) for MAP infection to influence CYP27B1 and CAMP expression, as TLR2 gene knockdown resulted in an average increase of 7.78 ± 0.88 and 13.90 ± 3.5 folds in their expression, respectively. MAP infection also clearly decreased the levels of p38 phosphorylation and showed dependency on the p38/MAPK pathway to influence the expression of CYP27B1, VDR, and CAMP which was evident by the average fold increase of 1.93 ± 0.28, 1.86 ± 0.27, and 6.34 ± 0.51 in their expression, respectively, following p38 antagonism. Finally, we showed that calcitriol treatment and p38/MAPK blockade reduce cellular oxidative stress and inflammatory markers in Caco-2 monolayers following macrophage-mediated MAP infection.

CONCLUSIONS

This study characterized the primary mechanism by which MAP infection leads to diminished levels of active vitamin D and cathelicidin in CD patients, which may explain the exacerbated vitamin D deficiency state in these cases.

Evaluation of Mucosal Healing in Crohn's Disease: Radiomics Models of Intestinal Wall and Mesenteric Fat Based on Dual-Energy CT

This study aims to assess the effectiveness of radiomics signatures obtained from dual-energy computed tomography enterography (DECTE) in the evaluation of mucosal healing (MH) in patients diagnosed with Crohn's disease (CD). In this study, 106 CD patients with a total of 221 diseased intestinal segments (79 with MH and 142 non-MH) from two medical centers were included and randomly divided into training and testing cohorts at a ratio of 7:3. Radiomics features were extracted from the enteric phase iodine maps and 40-kev and 70-kev virtual monoenergetic images (VMIs) of the diseased intestinal segments, as well as from mesenteric fat. Feature selection was performed using the least absolute shrinkage and selection operator (LASSO) logistic regression. Radiomics models were subsequently established, and the accuracy of these models in identifying MH in CD was assessed by calculating the area under the receiver operating characteristic curve (AUC). The combined-iodine model formulated by integrating the intestinal and mesenteric fat radiomics features of iodine maps exhibited the most favorable performance in evaluating MH, with AUCs of 0.989 (95% confidence interval (CI) 0.977-1.000) in the training cohort and 0.947 (95% CI 0.884-1.000) in the testing cohort. Patients categorized as high risk by the combined-iodine model displayed a greater probability of experiencing disease progression when contrasted with low-risk patients. The combined-iodine radiomics model, which is built upon iodine maps of diseased intestinal segments and mesenteric fat, has demonstrated promising performance in evaluating MH in CD patients.

New score models for assessing disease activity in Crohn's disease based on bowel ultrasound and biomarkers: Ideal surrogates for endoscopy or imaging

Disease activity evaluation is important in Crohn's disease (CD). We aimed to establish new disease activity indices for CD based on noninvasive parameters. The data of 110 patients with CD were retrospectively analyzed. Parameters from bowel ultrasound and biomarkers were measured to select the variables included in the models by univariate analysis. Logistic regression analysis was performed to predict mucosal and transmural activities defined by ileocolonoscopy or computed tomography enterography, respectively. The models' performance was measured by the area under the receiver operating characteristic (ROC) curve (AUC). Leave-one-out cross validation (LOOCV) was applied to adjust for overconfidence in the newly established score models. To predict mucosal activity, erythrocyte sedimentation rate (ESR) and (LimG × BWT)-SUM (the sum of the product of Limberg grade [LimG] and bowel wall thickness [BWT] of each bowel segment) were selected for model A, and the equation was A = 2 × ESR + 9.3 × (LimG × BWT)-SUM. The AUC of ROC, sensitivity, and specificity were 0.927%, 89.8%, and 86.4%, respectively. The AUC of the ROC curve verified by LOOCV was 0.913. To predict transmural activity, albumin (ALB) and LimG-SUM (the sum of the LimG of all the bowel segments) were selected for model B, which was established as B = -1.3 × ALB +1.7 × LimG-SUM. The AUC of ROC, sensitivity, and specificity were 0.851%, 78.0%, and 84.2%, respectively. The AUC of the ROC curve verified by LOOCV was 0.833. Nomograms were developed for two score models. New score models based on noninvasive parameters established in this study showed good abilities in detecting active disease and performed well in the validation phase.

Nomogram based on computed tomography images and clinical data for distinguishing between primary intestinal lymphoma and Crohn's disease: a retrospective multicenter study

Background

Differential diagnosis of primary intestinal lymphoma (PIL) and Crohn's disease (CD) is a challenge in clinical diagnosis.

Aims

To investigate the validity of the nomogram based on clinical and computed tomography (CT) features to identify PIL and CD.

Methods

This study retrospectively analyzed laboratory parameters, demographic characteristics, clinical manifestations, and CT imaging features of PIL and CD patients from two centers. Univariate logistic analysis was performed for each variable, and laboratory parameter model, clinical model and imaging features model were developed separately. Finally, a nomogram was established. All models were evaluated using the area under the curve (AUC), accuracy, sensitivity, specificity, and decision curve analysis (DCA).

Results

This study collected data from 121 patients (PIL = 69, CD = 52) from Center 1. Data from 43 patients (PIL = 24, CD = 19) were collected at Center 2 as an external validation cohort to validate the robustness of the model. Three models and a nomogram were developed to distinguish PIL from CD. Most models performed well from the external validation cohort. The nomogram showed the best performance with an AUC of 0.921 (95% CI: 0.838-1.000) and sensitivities, specificities, and accuracies of 0.945, 0.792, and 0.860, respectively.

Conclusion

A nomogram combining clinical data and imaging features was constructed, which can effectively distinguish PIL from CD.

Diagnostic accuracy of CT enterography correlated to histopathology in the diagnosis of small bowel Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory process affecting the gastrointestinal tract, mainly the terminal ileum of small bowel. Although ileocolonoscopy provides good mucosal visualization, it does not allow evaluation of extraluminal abnormalities. Computed tomographic enterography (CTE) is an emerging imaging modality for assessment of small bowel disorders. The study aimed to explore the diagnostic accuracy of CTE in the diagnosis of patients with CD benchmarked against a histopathological reference.

METHODS

A cross-sectional study entailed 126 consecutive patients with known or suspected CD who underwent CTE and biopsy by ileocolonoscopy via retrograde terminal ileum intubation. Spearman's rank was used to test the correlation and Kappa coefficient agreement between CTE and histopathology. Area under the curve (AUC) of receiver operating characteristic (ROC) was used to measure CTE diagnostic accuracy.

RESULTS

The overall sensitivity and specificity of CTE were 93.88% and 85.71%, respectively. The PPV was 95.83%, and the NPV was 80%. The accuracy of CTE indicated an overall probability of correct patient classification of 92.06%. The AUC of the ROC of CTE was 0.898 (P < 0.001). Thus, CTE has a high sensitivity for assessment of small bowel CD. The CTE and histopathological gradings were strongly correlated (Spearman's coefficient = 0.962, P < 0.001). CTE exhibited perfect agreement with histopathology (Kappa coefficient (κ) = 0.847, P < 0.001).

CONCLUSION

CTE is a reliable technique that has high diagnostic accuracy in the assessment of CD. Hence, it may be useful for follow up and for preoperative guidance in treatment planning.

Efficiency of dual-energy computed tomography enterography in the diagnosis of Crohn's disease

Background

This retrospective study aimed to investigate the usefulness of the optimized kiloelectron volt (keV) for virtual monoenergetic imaging (VMI) combined with iodine map in dual-energy computed tomography enterography (DECTE) in the diagnosis of Crohn’s disease (CD).

Methods

Seventy-two patients (mean age: 41.89 ± 17.28 years) with negative computed tomography enterography (CTE) were enrolled for investigating the optimized VMI keV in DECTE by comparing subjective and objective parameters of VMIs that were reconstructed from 40 to 90 keV. Moreover, 68 patients (38.27 ± 15.10 years; 35 normal and 33 CD) were included for evaluating the diagnostic efficacy of DECTE iodine map at the optimized VMI energy level and routine CTE for CD and active CD. Statistical analysis for all data was conducted.

Results

Objective and subjective imaging evaluations showed the best results at 60 keV for VMIs. The CT values of the normal group, active subgroup, and CD group during the small intestinal phase at routine 120 kVp or 60 keV VMI had significant differences. The diagnostic efficacy of an iodine map was the best when NIC = 4% or fat value = 45.8% for CD, whereas NIC < 0.35 or the fat value < 0.38 for active CD. The combined routine CTE and optimized VMI improved the diagnostic efficacy (P < 0.001).

Conclusions

VMI at 60 keV provided the best imaging quality on DECTE. NIC and fat value provided important basis for active CD evaluation. Routine CTE combined with VMI at 60 keV improved the diagnostic efficiency for CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-021-00716-y.

Relevance of monitoring transmural disease activity in patients with Crohn's disease: current status and future perspectives

Treatment targets of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD) have evolved over the last decade. Goals of therapy consisting of symptom control and steroid sparing have shifted to control of disease activity with endoscopic remission being an important endpoint. Unfortunately, this requires ileocolonoscopy, an invasive procedure. Biomarkers [C-reactive protein (CRP) and fecal calprotectin (FCP)] have emerged as surrogates for endoscopic remission and disease activity, but also have limitations. Despite this evolution, we must not lose sight that CD involves transmural inflammation, not fully appreciated with ileocolonoscopy. Therefore, transmural assessment of disease activity by cross-sectional imaging, in particular with magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS), is vital to fully understand disease control. Bowel-wall thickness (BWT) is the cornerstone in assessment of transmural inflammation and BWT normalization, with or without bloodflow normalization, the key element demonstrating resolution of transmural inflammation, namely transmural healing (TH) or transmural remission (TR). In small studies, achievement of TR has been associated with improved long-term clinical outcomes, including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. This review will focus on the existing literature investigating the concept of TR or residual transmural disease and its relation to other existing treatment targets. Current data suggest that TR may be the next logical step in the evolution of treatment targets.

Targeting the gut layers in Crohn's disease: mucosal or transmural healing?

INTRODUCTION

Although the landmark of Crohn's Disease (CD) is the transmural inflammation, mucosal healing (MH), which is assessed by colonoscopy, is currently the gold standard of CD management. Transmural healing (TH) is a new concept evaluated by cross-sectional imaging (CSI) techniques, such as bowel ultrasound (US), computed tomography enterography (CTE), and magnetic resonance enterography (MRE). Little is known about the clinical significance of persisting mural disease and the predictive value of complete TH.

AREAS COVERED

The authors reviewed the available literature on TH and its meaning as predictor of long-term outcomes in CD, to explore if TH may be a better target compared to MH in CD patients, in terms of disease outcome, such as medication changes, hospitalization, or surgery.

EXPERT OPINION

Some evidence suggests that achieving TH has a predictive value in CD management and correlates with better disease outcome than MH, although existing studies are few and with limitations. A definitive definition of TH is not yet established and the frequency or the preferred modality of TH evaluation remains unclear. Implementing TH in treat-to-target approach may enable stricter disease monitoring with noninvasive methods and finally change the disease course, preventing irreversible bowel damage.