Crohn's disease in Korea: past, present, and future

Construction of gene subgroups of Crohn disease based on transcriptome data

BACKGROUND

The global prevalence of Crohn disease (CD), a chronic inflammatory disease of the intestine, has been increasing; however, the etiology and pathogenesis of this disease have not been fully elucidated. Therefore, in the present study, we aimed to better understand the molecular mechanisms underlying CD to aid the development of novel therapeutic strategies for this condition.

METHODS

Based on the transcriptome data from patients with CD, this study used an unsupervised learning method to construct gene co-expression molecular subgroups and the R and SPSS software to identify the biological, clinical, and genetic characteristics and signatures of each subgroup.

RESULTS

Two subgroups were analyzed. Compared to subgroup II, subgroup I consisted of older patients with a more limited range of disease presentation and had a higher number of smokers. The specific genes associated with this subgroup, including CDKN2B, solute carrier family 22 member 5, and phytanoyl-CoA 2-hydroxylase, can be targeted for managing intestinal dysbacteriosis. The number of patients showing infiltrating lesions was higher, the number of smokers was lower, and CD severity was worse in patients in subgroup II than those in subgroup I. The specific genes relevant to subgroup II included cluster of differentiation 44, tryptophanyl-tRNA synthetase, and interleukin 10 receptor, alpha subunit, which may be related to viral infection.

CONCLUSION

The present study segregated patients with CD into 2 subgroups; the findings reported herein provide a new theoretical basis for the diagnosis and treatment of CD and could aid a thorough identification of potential therapeutic targets for this disease.

Anti-Saccharomyces cerevisiae Antibody in Pediatric Crohn's Disease Patients without Mucosal Healing Is a Useful Marker of Mucosal Damage

Background/Aims

We evaluated whether anti-Saccharomyces cerevisiae antibody (ASCA) titers are associated with diagnostic findings, disease activity, Paris classification phenotypes, and persistence after infliximab (IFX) treatment in children with Crohn’s disease (CD). We also investigated the role of ASCA as a predictor of mucosal healing (MH) and clinical remission (CR).

Methods

This study included 61 CD patients aged 19 years or younger who were diagnosed and treated between September 2010 and January 2019 and followed for at least 1 year. ASCA was regularly measured at the diagnosis of CD and at least 1 year after IFX therapy.

Results

The average follow-up period was 3.8±3.4 years (range, 1.0 to 7.2 years). Regression analysis showed that the ASCA titer was the only factor associated with Simple Endoscopic Score for Crohn's Disease (SES-CD) or CR among all the parameters. In patients who had achieved MH (SES-CD=0), ASCA immunoglobulin G (IgG) was not associated with MH, but in patients without MH, ASCA IgG was associated with SES-CD (p=0.005) and CR (p<0.001). The cutoff value of ASCA IgG in patients with CR was 21.8 units. However, there was no difference in the relapse rate between the ASCA IgG-positive and -negative groups during the follow-up period.

Conclusions

In patients who have not achieved MH, ASCA IgG is closely related to mucosal damage and CR. Unlike Western studies, ASCA IgG may be more helpful in predicting prognosis than immunoglobulin A in Korean patients, but it is not an appropriate indicator to predict the relapse of CD. (Gut Liver 2021;15-770)

Epidemiology and diagnosis of inflammatory bowel diseases

Background: Over the past three decades, inflammatory bowel diseases (IBD) have been rapidly increasing in the African, South American, and Asian countries, including Korea. However, in Korea, the public awareness of IBD remains low, and diagnostic delay is not uncommon due to the physicians' lack of clinical experience. It is essential to understand the trends and regional differences in the epidemiology of IBD for proper diagnosis and treatment.Current Concepts: Although lower than those of the West, the prevalence and incidence of IBD in Korea rank among the highest in Asia and are steadily increasing. In the past 10 years, the prevalence of IBD has almost doubled, while its incidence has decreased gradually. As compared to Western IBD patients, Korean patients have higher proportion of proctitis in ulcerative colitis, male predominance, more ileocolonic involvement, and higher incidence of perianal fistula in Crohn disease. There is no single gold standard for the diagnosis of IBD. Thus, diagnosis can be made by clinical evaluation, including a detailed history taking, physical examination, and a combination of endoscopic, radiologic, laboratory, and histologic findings.Discussion and Conclusion: Population-based studies have revealed the current trends and characteristics of the epidemiology of IBD in Korea. Continued education and development of diagnostic tools will help clinicians to diagnose IBD accurately and differentiate it from other diseases such as intestinal tuberculosis.

Comparative perianal fistula closure rates following autologous adipose tissue-derived stem cell transplantation or treatment with anti-tumor necrosis factor agents after seton placement in patients with Crohn's disease: a retrospective observational study

Background

Perianal fistula is one of the most common complications in Crohn’s disease, and various medical and surgical treatments are being tried. The aim of this study was to compare the perianal fistula closure rates following treatment with anti-tumor necrosis factor (TNF) agents or autologous adipose tissue-derived stem cell (auto-ASC) transplantation with Crohn’s disease (CD).

Methods

CD patients who underwent seton placement for perianal fistula from January 2015 to December 2019 at a tertiary referral center were retrospectively reviewed. Patients were divided into two groups, one that received sequential treatments with anti-TNF agents (anti-TNF group) and the other that underwent auto-ASC transplantation (stem cell group). Clinical variables and fistula closure rates were compared in the two groups.

Results

Of the 69 patients analyzed, 39 were treated with anti-TNF agents and 30 underwent auto-ASC transplantation. Compared with the stem cell group, patients in the anti-TNF group were older (p=0.028), were more frequently male (p=0.019), had fistulas with more penetrating behavior (p=0.002), had undergone surgery more frequently (p=0.010), and had a shorter interval from seton placement to intended treatment (p<0.001). During a median follow-up of 46 months (range, 30–52.5 months), fistula closure rates were significantly faster (83.3% vs. 23.1%, p<0.001), and the mean interval from seton placement to fistula closure significantly shorter (14 vs. 37 months, p<0.001) in the stem cell than in the anti-TNF group. Three patients experienced fistula recurrence, all in the stem cell group.

Conclusions

Medical treatment using anti-TNF agents and auto-ASC transplantation are feasible treatment options after seton placement for Crohn’s perianal fistula. However, the closure rate was significantly faster and the time to closure significantly shorter in patients who underwent auto-ASC transplantation than medical treatment.

Trial registration

This study was retrospectively registered and approved by the Institutional Review Board of Asan Medical Center, number 2020-1059.

Clinicopathological Characteristics and Surgical Outcomes of Crohn Disease-Associated Colorectal Malignancy

PURPOSE

Carcinoma arising from Crohn disease (CD) is rare, and there is no clear guidance on how to properly screen for at-risk patients and choose appropriate care. This study aimed to evaluate the clinicopathological characteristics, treatment, and oncologic outcomes of CD patients diagnosed with colorectal cancer (CRC).

METHODS

Using medical records, we retrospectively enrolled a single-center cohort of 823 patients who underwent abdominal surgery for CD between January 2006 and December 2015. CD-associated CRC patients included those with adenocarcinoma, lymphoma, or neuroendocrine tumors of the colon and rectum.

RESULTS

Nineteen patients (2.3%) underwent abdominal surgery to treat CD-associated CRC. The mean duration of CD in the CD-associated CRC group was significantly longer than that in the benign CD group (124.7 ± 77.7 months vs. 68.9 ± 60.2 months, P = 0.006). The CD-associated CRC group included a higher proportion of patients with a history of perianal disease (73.7% vs. 50.2%, P = 0.035) and colonic location (47.4% vs. 6.5%, P = 0.001). Among 19 CD-associated CRC patients, 17 (89.5%) were diagnosed with adenocarcinoma, and of the 17 cases, 15 (88.2%) were rectal adenocarcinoma. On multivariable analyses for developing CRC, only colonic location was a risk factor (relative risk, 7.735; 95% confidence interval, 2.862-20.903; P = 0.001).

CONCLUSION

Colorectal malignancy is rare among CD patients, even among patients who undergo abdominal surgery. Rectal adenocarcinoma accounted for most of the CRC, and colonic location was a risk factor for developing CRC.

Novel treatments for inflammatory bowel disease

Increased understanding of the immunopathology of inflammatory bowel disease (IBD) has led to the development of targeted therapies and has unlocked a new era in IBD treatment. The development of treatment options aimed at a variety of pathological mechanisms offers new hope for customized therapies. Beyond anti-tumor necrosis factor agents, selective lymphocyte trafficking inhibitors have been proposed as potent drugs for IBD. Among these, vedolizumab has recently been approved for both Crohn's disease and ulcerative colitis. Numerous other agents for IBD treatment are currently under investigation, including Janus kinase inhibitors, anti-mucosal vascular addressin cell adhesion molecule-1 agents, an anti-SMAD7 antisense oligonucleotide, an anti-interleukin-12/23 monoclonal antibody, and a sphingosine-1-phosphate receptor-1 selective agonist. These agents will likely expand the treatment options available for the management of IBD patients in the future. In this review, we discuss the efficacy and safety of novel agents currently under investigation in IBD clinical trials.

Long-Term Outcomes of Adalimumab Treatment in 254 Patients with Crohn's Disease: A Hospital-Based Cohort Study from Korea

BACKGROUND AND AIMS

Large-scale studies regarding the long-term outcomes of adalimumab (ADA) treatment in Asian patients with Crohn's disease (CD) are still scarce.

METHODS

We retrospectively analyzed the long-term outcomes of ADA treatment in Korean CD patients who commenced on scheduled ADA treatment at Asan Medical Center between November 2008 and July 2016. Clinical response was defined as maintaining ADA treatment without dose intensification (DI) and/or major abdominal surgery (MAS).

RESULTS

Of the 254 patients who received at least two doses of ADA at 2-week intervals as induction therapy, 250 patients (98.4%) showed an initial favorable response by week 4. Among responders, 243 patients were followed up for longer than 4 weeks and were included for further analysis. The median duration of ADA maintenance therapy was 19.4 months. At the last follow-up, 45 patients (18.5%) required DI after a median of 16.8 months and 31 (12.8%) required MAS after a median of 8.9 months. Finally, 161 patients (66.3%) were still receiving ADA without DI and/or MAS. The cumulative probability of maintaining ADA without DI and/or MAS was 81.1% at 1 year, and 36.5% at 5 years. Secondary loss of response to previous infliximab (P = 0.001) and elevated baseline C-reactive protein at starting ADA treatment (P = 0.008) were identified as independent predictors of a poor response to ADA treatment using multivariate regression analysis.

CONCLUSIONS

The long-term outcome of ADA treatment in a real-life cohort of Korean patients with CD appears to be comparable to that reported in previously published Western studies.

Factors Contributing to the Preference of Korean Patients with Crohn's Disease When Selecting an Anti-Tumor Necrosis Factor Agent (CHOICE Study)

Background/Aims

Two comparable anti-tumor necrosis factor (TNF) agents with different routes of administration (intravenous [iv] infliximab [IFX] vs subcutaneous [sc] adalimumab [ADA]) are available for patients with Crohn’s disease (CD) in Korea. This study aimed to identify the preferences of Korean CD patients for a specific anti-TNF agent and the factors contributing to the decision.

Methods

A prospective survey was performed among anti-TNF-naive CD patients in 10 tertiary referral hospitals. A 16-item questionnaire addressed patient preferences and the factors contributing to the decision in favor of a particular anti-TNF agent. A logistic regression was conducted to assess predictive factors for ADA preference.

Results

Overall, 189 patients (139 males; mean age, 32.47±11.71 years) completed the questionnaire. IFX and ADA were preferred by 63.5% (120/189) and 36.5% (69/189) of patients, respectively. The most influential reason for choosing IFX was ‘doctor’s presence’ (68.3%, 82/120), and ADA was “easy to use” (34.8%, 24/69). Amid various clinicodemographic data, having a >60-minute travel time to the hospital was a significant independent predictive factor for ADA preference.

Conclusions

A large number of anti-TNF-naive Korean patients with CD preferred anti-TNFs with an iv route of administration. The reassuring effect of a doctor’s presence might be the main contributing factor for this decision.

Fecal microbiota transplantation for refractory Crohn's disease

Approximately one-third of patients with Crohn's disease do not respond to conventional treatments, and some experience significant adverse effects, such as serious infections and lymphoma, and many patients require surgery due to complications. Increasing evidence suggests that specific changes in the composition of gut microbiota, termed as dysbiosis, are a common feature in patients with inflammatory bowel disease (IBD). Dysbiosis can lead to activation of the mucosal immune system, resulting in chronic inflammation and the development of mucosal lesions. Recently, fecal microbiota transplantation, aimed at modifying the composition of gut microbiota to overcome dysbiosis, has become a potential alternative therapeutic option for IBD. Herein, we present a patient with Crohn's colitis in whom biologic therapy failed previously, but clinical remission and endoscopic improvement was achieved after a single fecal microbiota transplantation infusion.

Effects of cytomegalovirus infection on the prognosis of inflammatory bowel disease patients

The aim of the present study was to investigate the effects of cytomegalovirus (CMV) infection on the prognosis of inflammatory bowel disease (IBD). Various databases were searched using a combination of keywords associated with CMV infection and IBD. Subsequent to the selection of relevant studies in line with strict inclusion and exclusion criteria, a meta-analysis was conducted using the Stata 12.0 software. A total of 195 studies were initially retrieved, including 28 studies in Chinese and 167 in English. Following the exclusion of unsuitable studies, 7 cohort studies with 374 IBD patients were included in the meta-analysis. The results of the present study identified significant differences between patients with and without CMV infection regarding the disease duration of IBD [standardized mean difference, -0.81; 95% confidence interval (CI), -1.19 to -0.43; P<0.001], the efficacy of corticosteroid therapy [relative risk (RR), 1.24; 95% CI, 1.02-1.49; P=0.029], the colectomy rate (RR, 2.13; 95% CI, 1.03-4.40; P=0.042) and the incidence of severe IBD (RR, 1.32; 95% CI, 1.04-1.67; P=0.022). Considering the IBD onset area, patients with CMV infection may have higher susceptibility to pancolitis (RR, 1.31; 95% CI; 1.01-1.72; P=0.045); however, no difference in susceptibility to left-sided IBD was observed between patients with or without CMV infection (RR, 0.97; 95% CI, 0.72-1.30; P=0.828). In conclusion, CMV infection may be associated with the disease duration, efficacy of corticosteroid therapy, colectomy rate, severe IBD incidence and disease location of IBD; thus, the presence of CMV infection may be considered as an important biomarker for determining the prognosis of IBD.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn’s disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients’ inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Making sense of the cause of Crohn's - a new look at an old disease

The cause of Crohn's disease (CD) has posed a conundrum for at least a century. A large body of work coupled with recent technological advances in genome research have at last started to provide some of the answers. Initially this review seeks to explain and to differentiate between bowel inflammation in the primary immunodeficiencies that generally lead to very early onset diffuse bowel inflammation in humans and in animal models, and the real syndrome of CD. In the latter, a trigger, almost certainly enteric infection by one of a multitude of organisms, allows the faeces access to the tissues, at which stage the response of individuals predisposed to CD is abnormal. Direct investigation of patients' inflammatory response together with genome-wide association studies (GWAS) and DNA sequencing indicate that in CD the failure of acute inflammation and the clearance of bacteria from the tissues, and from within cells, is defective. The retained faecal products result in the characteristic chronic granulomatous inflammation and adaptive immune response. In this review I will examine the contemporary evidence that has led to this understanding, and look for explanations for the recent dramatic increase in the incidence of this disease.

Correlations of Host Genetics and Gut Microbiome Composition

The human gut microbiome has a considerable impact on host health. The long list of microbiome-related health disorders raises the question of what in fact determines microbiome composition. In this review we sought to understand how the host itself impacts the structure of the gut microbiota population, specifically by correlations of host genetics and gut microbiome composition. Host genetic profile has been linked to differences in microbiome composition, thus suggesting that host genetics can shape the gut microbiome of the host. However, cause-consequence mechanisms behind these links are still unclear. A survey of the possible mechanisms allowing host genetics to shape microbiota composition in the gut demonstrated the major role of metabolic functions and the immune system. A considerable impact of other factors, such as diet, may outweigh the effects of host genetic background. More studies are necessary for good understanding of the relations between the host genetic profile, gut microbiome composition, and host health. According to the idea of personalized medicine, patient-tailored management of microbiota content remains a fascinating area for further inquiry.

Pharmacokinetics in Wistar Rats of 5-[(4-Carboxybutanoyl)Amino]-2-Hydroxybenzoic Acid: A Novel Synthetic Derivative of 5-Aminosalicylic Acid (5-ASA) with Possible Anti-Inflammatory Activity

5-[(4-carboxybutanoyl)amino]-2-hydroxybenzoic acid (C2) is a novel synthetic derivative of 5-aminosalicylic acid (5-ASA), which is currently being evaluated ex vivo as an anti-inflammatory agent and has shown satisfactory results. This study aimed to obtain the pharmacokinetic profiles, tissue distribution and plasma protein binding of C2 in Wistar Rats. Additionally, an HPLC method was developed and validated to quantify C2 in rat plasma. The pharmacokinetic profiles of intragastric, intravenous and intraperitoneal administration routes at singles doses of 100, 50, and 100 mg/kg, respectively, were studied in Wistar rats. The elimination half-life of intravenously administered C2 was approximately 33 min. The maximum plasma level of C2 was reached approximately 24 min after intragastric administration, with a Cmax value of 2.5 g/mL and an AUCtot value of 157 μg min-1/mL; the oral bioavailability was approximately 13%. Following a single intragastric or oral dose (100 mg/kg), C2 was distributed and detected in all examined tissues (including the brain and colon). The results showed that C2 accumulates over time. The plasma protein binding results indicated that the unbound fraction of C2 at concentrations of 1 to 20 μg/mL ranged from 89.8% to 92.5%, meaning that this fraction of C2 is available to cross tissues. Finally, the blood-plasma partitioning (BP ratio) of C2 in rat plasma was 0.71 and 0.6 at concentrations of 5 and 10 μg/mL, respectively, which indicates that C2 is free in the plasmatic phase and not inside blood cells. The results of this study suggest that a fraction of the administered C2 dose is absorbed in the stomach, and the fraction that is not absorbed reaches the small intestine and colon. This distribution constitutes the main advantage of C2 compared with 5-ASA for the treatment of ulcerative colitis (UC) and Crohn's disease (CD).

Recent insights into the molecular pathogenesis of Crohn's disease: a review of emerging therapeutic targets

Chronic inflammatory bowel diseases (IBDs) are a subject of great interest in gastroenterology, due to a pathological mechanism that is difficult to explain and an optimal therapeutic approach still undiscovered. Crohn's disease (CD) is one of the main entities in IBD, characterized by clinical polymorphism and great variability in the treatment response. Modern theories on the pathogenesis of CD have proven that gut microbiome and environmental factors lead to an abnormal immune response in a genetically predisposed patient. Genome-wide association studies in patients with CD worldwide revealed several genetic mutations that increase the risk of IBD and that predispose to a more severe course of disease. Gut microbiota is considered a compulsory and an essential part in the pathogenesis of CD. Intestinal dysmicrobism with excessive amounts of different bacterial strains can be found in all patients with IBD. The discovery of Escherichia coli entero-invasive on resection pieces in patients with CD now increases the likelihood of antimicrobial or vaccine-type treatments. Recent studies targeting intestinal immunology and its molecular activation pathways provide new possibilities for therapeutics. In addition to antitumor necrosis factor molecules, which were a breakthrough in IBD, improving mucosal healing and resection-free survival rate, other classes of therapeutic agents come to focus. Leukocyte adhesion inhibitors block the leukocyte homing mechanism and prevent cellular immune response. In addition to anti-integrin antibodies, chemokine receptor antagonists and SMAD7 antisense oligonucleotides have shown encouraging results in clinical trials. Micro-RNAs have demonstrated their role as disease biomarkers but it could also become useful for the treatment of IBD. Moreover, cellular therapy is another therapeutic approach under development, aimed for severe refractory CD. Other experimental treatments include intravenous immunoglobulins, exclusive enteral nutrition, and granulocyte colony-stimulating factors.

Multiple Enteroenteric Fistulas- Crohn's Disease- A Case Report

Crohn's disease is a type of chronic inflammatory bowel disease (IBD) of unknown etiology that may affect any part of the gastrointestinal tract from mouth to anus and shows extra-intestinal involvement. It characteristically shows skip lesions. This case report reported in 2014 describes a middle age Pakistani male known to have documented evidence of significant crohn's disease since past 18 years. He was diagnosed with multiple fistulas that are a rare entity of patients with crohn's disease, which is itself a rare disease in Asian countries.

Inflammatory Bowel Disease Cohort Studies in Korea: Present and Future

Inflammatory bowel disease (IBD) is defined as a chronic and relapsing inflammatory disorder of the intestine. Intestinal inflammation in IBD has been proposed to be attributable to the interplay between microbial, genetic, environmental, and immunological factors. The incidence and prevalence rates of IBD are rapidly increasing apparently in other parts of the world, with dramatic increases especially in East Asia. Generally, cohort studies are useful for estimating the incidence, prevalence, natural course, prognosis, and risk factors of diseases. In particular, cohort studies performed in Western countries have well described the prevalence, risk factors, and natural course of IBD and investigated its genetic pathophysiology. However, the outcomes of IBD cohort studies performed in Korea are not as persuasive as those of Western studies because of the relatively low prevalence of IBD and short follow-up periods of the cohorts in Korea. Despite this critical limitation, members of the Korean Association for the Study of Intestinal Diseases have demonstrated outstanding results. Some unique features of IBD patients in Korea are well demonstrated, such as thiopurine-induced leukopenia or risks of opportunistic tuberculosis infection in patients receiving tumor necrosis factor-α inhibitors. In this review, the present authors summarized the key points of the results of the cohort studies performed in Korea and explored future perspectives.