Targeting Specific Immunologic Pathways in Crohn's Disease

Single cell atlas of human gastric muscle immune cells and macrophage-driven changes in idiopathic gastroparesis

Gastrointestinal immune cells, particularly muscularis macrophages (MM) interact with the enteric nervous system and influence gastrointestinal motility. Here we determine the human gastric muscle immunome and its changes in patients with idiopathic gastroparesis (IG). Single cell sequencing was performed on 26,000 CD45+ cells obtained from the gastric tissue of 20 subjects. We demonstrate 11 immune cell clusters with T cells being most abundant followed by myeloid cells. The proportions of cells belonging to the 11 clusters were similar between IG and controls. However, 9/11 clusters showed 578-11,429 differentially expressed genes. In IG, MM had decreased expression of tissue-protective and microglial genes and increased the expression of monocyte trafficking and stromal activating genes. Furthermore, in IG, IL12 mediated JAK-STAT signaling involved in the activation of tissue-resident macrophages and Eph-ephrin signaling involved in monocyte chemotaxis were upregulated. Patients with IG had a greater abundance of monocyte-like cells. These data further link immune dysregulation to the pathophysiology of gastroparesis.

The Impact of Vedolizumab on Pre-Existing Extraintestinal Manifestations of Inflammatory Bowel Disease: A Multicenter Study

BACKGROUND

There are limited data on how vedolizumab (VDZ) impacts extraintestinal manifestations (EIMs) in inflammatory bowel disease (IBD). The aim of this study was to determine the clinical outcomes of EIMs after initiation of VDZ for patients with IBD.

METHODS

A multicenter retrospective study of patients with IBD who received at least 1 dose of VDZ between January 1, 2014 and August 1, 2019 was conducted. The primary outcome was the rate of worsening EIMs after VDZ. Secondary outcomes were factors associated with worsening EIMs and peripheral arthritis (PA) specifically after VDZ.

RESULTS

A total of 201 patients with IBD (72.6% with Crohn disease; median age 38.4 years (interquartile range, 29-52.4 years); 62.2% female) with EIMs before VDZ treatment were included. The most common type of EIM before VDZ was peripheral arthritis (PA) (68.2%). Worsening of EIMs after VDZ occurred in 34.8% of patients. There were no statistically significant differences between the worsened EIM (n = 70) and the stable EIM (n = 131) groups in term of age, IBD subtype, or previous and current medical therapy. We found that PA was significantly more common in the worsening EIM group (84.3% vs 59.6%; P < 0.01). Worsening of EIMs was associated with a higher rate of discontinuation of VDZ during study follow-up when compared with the stable EIM group (61.4% vs 44%; P = 0.02). Treatment using VDZ was discontinued specifically because of EIMs in 9.5% of patients.

CONCLUSIONS

Almost one-third of patients had worsening EIMs after VDZ, which resulted in VDZ discontinuation in approximately 10% of patients. Previous biologic use or concurrent immunosuppressant or corticosteroid therapy did not predict EIM course after VDZ.

Medical and Endoscopic Management of Crohn Disease

ABSTRACT

In this review, through a series of questions and answers, we explore the current approach to classifying patients with Crohn disease into low-risk (mild-moderate) and high-risk (moderate-severe) categories with the recommended treatment approaches per guidelines from the International Organization for the Study of Inflammatory Bowel Diseases, American Gastroenterological Association, the American College of Gastroenterology, and the European Crohn's and Colitis Organization detailed here. The development pipeline of potential therapies is also summarized. We also review key information from magnetic resonance enterography and pelvis imaging studies that the abdominal radiologist can communicate to a multidisciplinary treatment team that includes gastroenterologists and colorectal surgeons, with a goal of achieving optimal patient outcomes. Lastly, endoscopic and radiological treatment targets in a treat-to-target approach in Crohn disease are explored.

Thalidomide Prevented and Ameliorated Pathogenesis of Crohn's Disease in Mice via Regulation of Inflammatory Response and Fibrosis

Crohn's disease (CD) is a chronic, relapsing form of inflammatory bowel disease, seriously threatening human health. Thalidomide has been used for the treatment of CD. However, the effects and the possible mechanisms of thalidomide on CD are still unclear. Herein, our study demonstrated that thalidomide protected colon mucosa against trinitro-benzene-sulfonic acid (TNBS)-induced injury, diminished inflammatory infiltration and levels of IFN-γ, IGF-1, IL-6, IL-17, TNF-α, while increased the levels of IL-10 and TGF-γ. Moreover, it reversed the intestinal fibrosis and inhibited the accumulated infiltration, down-regulated the expression of col1a2, col3a2, MMP-3, MMP-9, MMP-1, TGF-γ, α-SMA, but up-regulated the expression of TIMP-1 and Vimentin. Although it could be observed that the effect of thalidomide administration in modeling was better than after modeling, there was no statistical difference between the two groups. The present study provided evidence that the therapeutic effect of thalidomide alleviated the inflammatory response and damage of colon tissue, mainly by restoring the imbalance of TH17/Treg cells and inhibiting intestinal fibrosis in TNBS-induced mice colitis.

Cytokine Receptor Profiling in Human Colonic Subepithelial Myofibroblasts: A Differential Effect of Th Polarization-Associated Cytokines in Intestinal Fibrosis

BACKGROUND

Colonic subepithelial myofibroblasts (cSEMFs) are mesenchymal cells with a pivotal role in the pathophysiology of Crohn's disease (CD) fibrosis. Here, we demonstrate for the first time a complete expression mapping of cytokine receptors, implicated in inflammatory bowel diseases, in primary human cSEMFs and how pro-inflammatory cytokines regulate this expression. Furthermore, we show the effect of Th1-, Th2-, Th17- and Treg-related cytokines on a fibrosis-related phenotype of cSEMFs.

METHODS

Colonic subepithelial myofibroblasts were isolated from healthy individuals' colonic biopsies. Interleukin (IL)-1α- and/or tumor necrosis factor (TNF)-α-induced mRNA and protein expression of cytokine receptors was assayed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunofluorescence, respectively. Th-related cytokine effects on mRNA and protein profibrotic factor expression were analyzed by qRT-PCR and/or colorimetric assays and on the wound-healing capacity of cSEMFs by scratch test.

RESULTS

In cSEMFs, we observed basal cytokine receptor expression, which was modified by IL-1α and TNF-α. Th1-related cytokines upregulated tissue factor (TF), collagen, fibronectin and matrix metalloproteinase (MMP)-1 and downregulated α-smooth muscle actin (α-SMA), MMP-9, and wound healing rate. Th2-related cytokines upregulated collagen, TF, α-SMA, MMP-1, and wound healing rate and downregulated fibronectin and MMP-9. IL-17 and IL-23 upregulated fibronectin, and IL-22 downregulated TF. IL-17 and IL-22 decreased wound healing rate. Similar to TGF-β, IL-23 upregulated MMP-1, tissue inhibitor of metalloproteinases-1, collagen expression, and wound healing rates.

CONCLUSIONS

Our results suggest that cSEMFs have a central role in inflammation and fibrosis, as they express a great variety of Th-related cytokine receptors, making them responsive to pro-inflammatory cytokines, abundant in the inflamed mucosa of CD patients.

Total flavone of Abelmoschus manihot suppresses epithelial-mesenchymal transition via interfering transforming growth factor-β1 signaling in Crohn’s disease intestinal fibrosis

AIM

To explore the role and mechanism of total flavone of Abelmoschus manihot (TFA) on epithelial-mesenchymal transition (EMT) progress of Crohn’s disease (CD) intestinal fibrosis.

METHODS

First, CCK-8 assay was performed to assess TFA on the viability of intestinal epithelial (IEC-6) cells and select the optimal concentrations of TFA for our further studies. Then cell morphology, wound healing and transwell assays were performed to examine the effect of TFA on morphology, migration and invasion of IEC-6 cells treated with TGF-β1. In addition, immunofluorescence, real-time PCR analysis (qRT-PCR) and western blotting assays were carried out to detect the impact of TFA on EMT progress. Moreover, western blotting assay was performed to evaluate the function of TFA on the Smad and MAPK signaling pathways. Further, the role of co-treatment of TFA and si-Smad or MAPK inhibitors has been examined by qRT-PCR, western blotting, morphology, wound healing and transwell assays.

RESULTS

In this study, TFA promoted transforming growth factor-β1 (TGF-β1)-induced (IEC-6) morphological change, migration and invasion, and increased the expression of epithelial markers and reduced the levels of mesenchymal markers, along with the inactivation of Smad and MAPK signaling pathways. Moreover, we revealed that si-Smad and MAPK inhibitors effectively attenuated TGF-β1-induced EMT in IEC-6 cells. Importantly, co-treatment of TFA and si-Smad or MAPK inhibitors had better inhibitory effects on TGF-β1-induced EMT in IEC-6 cells than either one of them.

CONCLUSION

These findings could provide new insight into the molecular mechanisms of TFA on TGF-β1-induced EMT in IEC-6 cells and TFA is expected to advance as a new therapy to treat CD intestinal fibrosis.