Mucosal healing as a treatment for IBD?

Quantitative Phase Imaging Using Digital Holographic Microscopy to Assess the Degree of Intestinal Inflammation in Patients with Ulcerative Colitis

Ulcerative colitis (UC) is characterized by chronic inflammation of the colorectum. Histological remission has emerged as a potential future treatment goal; however, the histopathological assessment of intestinal inflammation in UC remains challenging with a multitude of available scoring systems and the need for a pathologist with expertise in inflammatory bowel disease (IBD). In previous studies, quantitative phase imaging (QPI) including digital holographic microscopy (DHM) was successfully applied as an objective method for stain-free quantification of the degree of inflammation in tissue sections. Here, we evaluated the application of DHM for the quantitative assessment of histopathological inflammation in patients with UC. In our study, endoscopically obtained colonic and rectal mucosal biopsy samples from 21 patients with UC were analyzed by capturing DHM-based QPI images that were subsequently evaluated using the subepithelial refractive index (RI). The retrieved RI data were correlated with established histological scoring systems including the Nancy index (NI) as well as with endoscopic and clinical findings. As a primary endpoint, we found a significant correlation between the DHM-based retrieved RI and the NI (R² = 0.251, p < 0.001). Furthermore, RI values correlated with the Mayo endoscopic subscore (MES; R² = 0.176, p < 0.001). An area under the receiver operating characteristics (ROC) curve of 0.820 confirms the subepithelial RI as a reliable parameter to distinguish biopsies with histologically active UC from biopsies without evidence of active disease as determined by conventional histopathological examination. An RI higher than 1.3488 was found to be the most sensitive and specific cut-off value to identify histologically active UC (sensitivity of 84% and specificity of 72%). In conclusion, our data demonstrate DHM to be a reliable tool for the quantitative assessment of mucosal inflammation in patients with UC.

Targeting neutrophils in inflammatory bowel disease: revisiting the role of adsorptive granulocyte and monocyte apheresis

INTRODUCTION

Inflammatory bowel disease (IBD) is a chronic immune-mediated disease of the gastrointestinal tract comprising Crohn's disease (CD) and ulcerative colitis (UC). While any part of the digestive tract can be affected in CD, mucosal inflammation in UC is limited to the colon. Differences and similarities between the two conditions are reflected by their pathophysiology.

AREAS COVERED

An overview of immunological aspects, pharmacological management, and biomarkers of IBD is provided. The role of adsorptive granulocyte and monocyte apheresis (GMA) is reviewed including its primary and secondary effects on the immune system, as well as clinical studies in IBD (mainly UC), and potential biomarkers for adsorptive GMA.

EXPERT OPINION

In UC, adsorptive GMA with Adacolumn (Adacolumn®, JIMRO Co., Ltd. Takasaki, Gunma, Japan) selectively depletes elevated myeloid lineage leukocytes and has a range of beneficial secondary immune effects. Adsorptive GMA is a safe and effective non-pharmacological treatment option for UC. Pilot studies have reported promising results for adsorptive GMA in combination with biological agents, although larger studies are required. Fecal calprotectin concentrations, neutrophil counts in histological samples and/or the neutrophil/lymphocyte ratio in peripheral blood may prove to be useful biomarkers for predicting GMA effectiveness in the future.

Systematic review and meta-analysis: the advantage of endoscopic Mayo score 0 over 1 in patients with ulcerative colitis

Background

Mucosal healing (MH) evaluated by endoscopy is a novel target of therapy in UC as it is associated with improved long-term outcomes. It is defined based on the Mayo endoscopic score (MES), but it is still to define whether a value of MES 0 or 1 should be the target. The purpose of this paper is to present the results of a systematic review with meta-analysis which compares long-term outcomes of patients in steroid-free clinical remission with MES 0 with those with MES 1.

Methods

A systematic electronic search of the literature was performed using Medline, Scopus, and CENTRAL through December 2020 (PROSPERO n:CRD42020179333). The studies concerned UC patients, in steroid-free clinical remission, with MES of 0 or 1, and with at least 12-months of follow-up.

Results

Out of 4611 citations, 15 eligible studies were identified. Increases in clinical relapse among patients with MES 1 were observed in all the studies included in this review, suggesting that MES of 1 have a higher risk of relapse than a score of 0. MES 0 patients displayed a lower risk of clinical relapse (OR 0.33; 95% CI 0.26–0.43; I² 13%) irrespective of the follow-up time (12-months or longer). On the other hand, no differences were found comparing MES 0 versus MES 1 about the risk of hospitalization or colectomy.

Conclusions

MES 0 is associated with a lower rate of clinical relapse than is MES 1. For this reason, MES 0, rather than MES 0–1, should be considered the therapeutic target for patients with UC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02157-5.

Serum exosomal microRNA-144-3p: a promising biomarker for monitoring Crohn's disease

Background

Crohn’s disease (CD) has a tendency for recurrence and requires adequate monitoring and personalized treatment. Since endoscopy is considerably invasive, serum biomarkers are required as alternatives for CD monitoring. Toward this, exosomal microRNAs (miRNAs) may serve as promising candidates. In this study, we aimed to assess the role of serum exosomal microRNA-144-3p (miR-144-3p) as a biomarker for CD monitoring.

Methods

We prospectively recruited 154 patients without a history of surgery (Cohort 1) and 75 patients who were to undergo intestinal resection (Cohort 2). Serum samples were collected from Cohort 1 before colonoscopy and from Cohort 2 before surgery and during post-operative colonoscopic examination. The serum levels of exosomal miR-144-3p were measured using quantitative reverse-transcription polymerase chain reaction (PCR). Correlations between relative exosomal miR-144-3p levels, disease activity, and disease behavior were analysed. The area under the receiver-operating characteristic curve (AUC) was used to assess the predictive value of exosomal miR-144-3p regarding mucosal activity and post-operative recurrence.

Results

A 3.33-fold increase in serum exosomal miR-144-3p levels was recorded in patients with CD compared with those in healthy controls (P < 0.001). The exosomal miR-144-3p levels were positively correlated with the simple endoscopic score of CD (ρ = 0.547, P < 0.001) as well as the Rutgeerts score (ρ = 0.478, P < 0.001). Elevated exosomal miR-144-3p levels were correlated with the penetrating disease with high specificity (100% [95% confidence interval, 95.1%–100%]). The accuracy of exosomal miR-144-3p for identifying post-operative recurrence was higher than that of C-reactive protein (CRP) (AUC, 0.775 vs 0.639; P < 0.001).

Conclusions

Serum exosomal miR-144-3p is a reliable biomarker of mucosal inflammation and penetrating CD. It may identify endoscopic CD recurrence after intestinal resection with higher accuracy than CRP testing.

WD40 Repeat Protein 26 Negatively Regulates Formyl Peptide Receptor-1 Mediated Wound Healing in Intestinal Epithelial Cells

N-formyl peptide receptors (FPRs) serve as phagocyte pattern-recognition receptors that play a crucial role in the regulation of host defense against infection. Epithelial cells also express FPRs, and their activation during inflammation or injury results in enhanced epithelial migration and proliferation and improved mucosal wound repair. However, signaling mechanisms that govern epithelial FPR1 activity are not well understood. This study identified a novel FPR1-interacting protein, WD40 repeat protein (WDR)-26, which negatively regulates FPR1-mediated wound healing in intestinal epithelial cells. We show that WDR26-mediated inhibition of wound repair is mediated through the inhibition of Rac family small GTPase 1 and cell division cycle 42 activation, as well as downstream intracellular reactive oxygen species production. Furthermore, on FPR1 activation with N-formyl-methionyl-leucyl phenylalanine, WDR26 dissociates from FPR1, resulting in the activation of downstream cell division cycle 42/Rac family small GTPase 1 signaling, increased epithelial cell migration, and mucosal wound repair. These findings elucidate a novel regulatory function of WDR26 in FPR1-mediated wound healing in intestinal epithelial cells.

IL-8 and LYPD8 expression levels are associated with the inflammatory response in the colon of patients with ulcerative colitis

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disorder affecting the large intestine, which may involve mucosal degeneration. Glycoproteins, mucin2 (MUC2) and the LY6/PLAUR domain containing 8 (LYPD8) are present on the mucous layer of the colon and can hinder the invasion of bacteria, thus contributing to the prevention of colitis. The present study investigated the expression levels of interleukin-8 (IL-8), MUC2 and LYPD8 on the mucous membranes of patients with UC. A total of 18 patients with UC (6 females and 12 males) were examined. Biopsies of the lesions as well as matching normal membranes were obtained and the mRNA expression levels of IL-8, MUC2 and LYPD8 were compared. LYPD8 expression was downregulated in the lesions and the relapsing-remitting subtype of lesions was associated with higher levels of MUC2 expression compared with single attack and chronic lesions subtypes. A positive correlation between Matts' histopathological grade and IL-8, as well as a negative correlation between Matts' histopathological grade and LYPD8 were observed. The expression levels of LYPD8 were lower in highly active lesions and these levels decreased according to the intensity of the mucosal inflammation. Conversely, an increase in MUC2 expression levels may reflect the recovery of the outer mucus layer in the remission phase. Therefore, the examination of MUC2 and LYPD8 expression levels may be useful indicators of mucosal healing in patients with UC.

Desmocollin-2 promotes intestinal mucosal repair by controlling integrin-dependent cell adhesion and migration

The intestinal mucosa is lined by a single layer of epithelial cells that forms a tight barrier, separating luminal antigens and microbes from underlying tissue compartments. Mucosal damage results in a compromised epithelial barrier that can lead to excessive immune responses as observed in inflammatory bowel disease. Efficient wound repair is critical to reestablish the mucosal barrier and homeostasis. Intestinal epithelial cells (IEC) exclusively express the desmosomal cadherins, Desmoglein-2 and Desmocollin-2 (Dsc2) that contribute to mucosal homeostasis by strengthening intercellular adhesion between cells. Despite this important property, specific contributions of desmosomal cadherins to intestinal mucosal repair after injury remain poorly investigated in vivo. Here we show that mice with inducible conditional knockdown (KD) of Dsc2 in IEC (Villin-Cre^ERT2; Dsc2 ^fl/fl) exhibited impaired mucosal repair after biopsy-induced colonic wounding and recovery from dextran sulfate sodium-induced colitis. In vitro analyses using human intestinal cell lines after KD of Dsc2 revealed delayed epithelial cell migration and repair after scratch-wound healing assay that was associated with reduced cell–matrix traction forces, decreased levels of integrin β1 and β4, and altered activity of the small GTPase Rap1. Taken together, these results demonstrate that epithelial Dsc2 is a key contributor to intestinal mucosal wound healing in vivo.

Defining Endoscopic Remission in Ileocolonic Crohn's Disease: Let's Start from Scratch

Endoscopic remission is the cornerstone of drug development and the guidance for daily clinical practice in Crohn's disease [CD]. However, although scoring systems for endoscopic activity in CD have been available for more than three decades, no consensus exists on the definition of endoscopic remission. In this viewpoint we describe the shortcomings of the current definition of endoscopic remission in ileocolonic CD and the essential requirements for a newly developed endoscopic scoring tool for endoscopic remission in CD.

Sustained Clinical Efficacy and Mucosal Healing of Thiopurine Maintenance Treatment in Ulcerative Colitis: A Real-Life Study

BACKGROUND AND AIMS

Thiopurines are commonly used for treating ulcerative colitis (UC), despite the fact that controlled evidence supporting their efficacy is limited. The aim of this study was to evaluate the long-term outcome of thiopurines as maintenance therapy in a large cohort of UC patients.

METHODS

All UC patients receiving thiopurine monotherapy at three tertiary IBD centers from 1995 to 2015 were identified. The primary endpoint was steroid-free clinical remission. Secondary endpoints were mucosal healing (MH), defined as Mayo endoscopic subscore 0, long-term safety, and predictors of sustained clinical remission.

RESULTS

We identified 192 patients, contributing a total of 747 person-years of follow-up (median follow-up 36 months, range 1-210 months). Steroid dependency was the most common indication for thiopurine treatment (58%). Steroid-free remission occurred in 45.3% of patients; 36.3% stopped thiopurines because of treatment failure and 18.2% for adverse events or intolerance. The cumulative probability of maintaining steroid-free remission while on thiopurine treatment was 87%, 76%, 67.6%, and 53.4% at 12, 24, 36, and 60 months, respectively. MH occurred in 57.9% of patients after a median of 18 months (range 5-96). No independent predictors of sustained clinical remission could be identified.

CONCLUSIONS

Thiopurines represent an effective and safe long-term maintenance therapy for UC patients.

Top-down approach to biological therapy of Crohn's disease

INTRODUCTION

Crohn's disease (CD) is a chronic, immune-mediated condition with a potentially disabling and destructive course. Despite growing data on when to use a therapeutic 'top-down' strategy, clinical management of this complex disorder is still challenging. Currently, the discussion of 'top-down' strategy in CD mostly includes biological therapy alone or in combination. Areas covered: This article is based on a review of existing literature regarding the use of biological therapy in a 'top-down' approach for the treatment of Crohn's disease. The authors reviewed all the major databases including MEDLINE as well as DDW and ECCO abstracts, respectively. Expert opinion: A 'top-down' therapeutic approach in Crohn's disease is strongly supported by existing data in patients with several risk factors for a severe course of disease. Moreover, there is an increasing amount of published data recommending a more individualised therapeutic strategy to identify candidates for 'top-down' treatment, based on enhanced diagnostics using biomarkers. Emerging therapeutic approaches besides existing therapy concepts using biologicals may possibly redefine the 'top-down' therapeutic strategy for Crohn's disease in the future.

Current stage in inflammatory bowel disease: What is next?

In recent years, the incidence of inflammatory bowel disease (IBD) has been on the rise, extending to countries where it was infrequent in the past. As a result, the gap between high and low incidence countries is decreasing. The disease, therefore, has an important economic impact on the healthcare system. Advances in recent years in pharmacogenetics and clinical pharmacology have allowed for the development of treatment strategies adjusted to the patient profile. Concurrently, new drugs aimed at inflammatory targets have been developed that may expand future treatment options. This review examines advances in the optimization of existing drug treatments and the development of novel treatment options for IBD.