Very early-onset inflammatory bowel disease in Japan: A nationwide survey

Disease phenotypic and outcome of very-early onset inflammatory bowel disease in Asian children: an understudied population

Background

There is a paucity of knowledge on disease phenotype and outcome of very early-onset (VEO) inflammatory bowel disease (VEO-IBD) from recently developed and developing countries, including from Southeast Asia. We studied disease phenotype, clinical characteristics, management and outcome of VEO-IBD in South and Southeast Asian children.

Materials and methods

We extracted data from a multicentre Asian pediatric (onset <18 years) IBD registry. VEO- and later-onset pediatric (LO-p) IBD were defined as onset of disease <6 years and ≥6 years, respectively. We excluded monogenic IBD.

Results

Of 440 children with IBD cases; 112 (25.5%) were VEO-IBD; Crohn's disease (CD) 36 (32.1%); ulcerative colitis (UC) 68 (60.7%), and IBD-unspecified 7 (7.1%). UC was more common in VEO-IBD while CD more common in LO-pIBD (CD = 68.9% vs. UC = 25.9%; p < 0.001). Disease location/extent of disease and disease severity were similar in both age groups for both CD and UC. For CD, inflammatory disease behavior was equally common in both age group (77.8% in VEO-IBD vs. 76.6% of LO-pIBD), majority had isolated colonic disease (27.8% VEO-IBD vs. 36.3% LO-pIBD), while stricturing and penetrating diseases were not observed in VEO-CD, but noted in 4.9% and 8.4% of LO-pCD, respectively. Among UC cases, pancolitis was observed in 60.3% of VEO-IBD vs. 65.9% of LO-pIBD. Most UC never had severe disease regardless of age group. Five years after diagnosis, VEO-IBD were more likely to have corticosteroids, immunomodulators or biologics than LO-pIBD. Despite this, inactive/mild disease activity was the predominant outcome at 5 year follow up for both VEO-CD (98.2%) and VEO- UC (96.1%). Bowel surgery rate was 2.4% and 1.7% for VEO- and LO-IBD at 5 years, respectively.

Conclusions

Despite differences in disease phenotype at diagnosis, disease behaviour, location/extent and disease severity were similar between VEO- and LO-IBD, with a comparable overall clinical remission rates between both age groups at 5 years after diagnosis.

Summary Concerning 16 Years of Research Activities in the Department of Pediatrics at Juntendo University

I described mainly about my research activities in the 16 years and 8 months since I became professor of pediatrics at Juntendo University. Since the fulfillment of research activities has a great influence on clinical activities, and sufficient research cannot be conducted without enhanced educational activities, I have tried to maintain a good balance between clinical practice, research, and education. Research activities in our department often depend on the research abilities of graduate students, but the leadership skills of the professors and associate and assistant professors who supervise the research are also important. First, I talked about the main research of the 12 research groups in our department. In addition, my specialty is pediatric gastroenterology and nutrition, and it is no exaggeration to say that Juntendo Pediatrics is one of the leaders in the field of pediatric gastroenterology and nutrition. I also provided a detailed explanation of research on pediatric inflammatory bowel disease (IBD), which is currently the most important research topic in our department. I hope that this environment will continue to foster the research mindset of young people in a natural way.

Tarm1 may affect colitis by regulating macrophage M1 polarization in a mouse colitis model

BACKGROUND

In this study, we aimed to explore the role of Tarm1 in juvenile mice with dextran sulfate sodium (DSS)-induced colitis and elucidate the mechanisms that affect intestinal barrier function.

METHODS

A DSS-induced pediatric inflammatory bowel disease mouse model was established using 4-week-old juvenile mice. Disease activity index and histopathological damage scores were determined using hematoxylin and eosin (H&E) staining. Tarm1, F4/80, CD68, and CD86 levels were detected using qPCR, western blotting, and immunofluorescence. Trans epithelial electric resistance (TEER) was detected using the transwell assay.

RESULTS

Results revealed that juvenile colitis mice fed 4% DSS drinking water had increased Tarm1 expression in the colon tissue, increased macrophage M1 polarization, higher expression of pro-inflammatory cytokines, and an impaired intestinal mucosal barrier, compared with the control group. Tarm1-knockdown RAW264.7 cells inhibited lipopolysaccharide (LPS)-induced M1 polarization and attenuated barrier damage in co-cultured intestinal epithelial cells.

CONCLUSION

Tarm1 expression was increased in colonic tissues of juvenile mice with colitis, and LPS-induced M1 polarization and intestinal barrier damage were attenuated in Tarm1-knockdown RAW264.7 cells. This suggests that attenuation of Tarm1 expression is a potential target for pediatric inflammatory bowel disease therapy.

Macrophage polarization in inflammatory bowel disease

The growing prevalence of inflammatory bowel disease (IBD) has encouraged research efforts, which have contributed to gradual improvements in our understanding of IBD diagnosis and therapeutic approaches. The pathogenesis of IBD has not been fully elucidated; however, the combined actions of environmental, genetic, immune factors, and microbial organisms are believed to cause IBD. In the innate immune system, macrophages play important roles in maintaining intestinal health and in the development of IBD. Macrophages can be polarized from M0 into several phenotypes, among which M1 and M2 play critical roles in IBD development and the repair of intestinal homeostasis and damage. Certain macrophage-related IBD studies already exist; however, the functions of each phenotype have not been fully elucidated. As technology develops, understanding the link between macrophages and IBD has increased, including the growing knowledge of the developmental origins of intestinal macrophages and their performance of comprehensive functions. This review describes macrophage polarization in IBD from the perspectives of macrophage development and polarization, macrophage changes in homeostasis and IBD, metabolic changes, and the mechanisms of macrophage polarization in IBD. The discussion of these topics provides new insights into immunotherapy strategies for IBD. Video Abstract.

Attenuated Expression of SLCO2A1 Caused by DNA Methylation in Pediatric Inflammatory Bowel Disease

BACKGROUND

SLCO2A1 encodes a prostaglandin (PG) transporter, and autosomal recessive pathogenic variants of this gene cause chronic enteropathy associated with SLCO2A1. It is unclear whether a heterozygous pathogenic variant of SLCO2A1 has a role in the pathogenesis of other types of inflammatory bowel disease (IBD). In this study, we investigated the possible involvement of a local epigenetic alteration in SLCO2A1 in patients with a heterozygous pathogenic variant.

METHODS

We conducted whole-exome sequencing of samples from 2 sisters with suspected monogenic IBD. In addition, we performed bisulfite sequencing using DNA extracted from their small and large intestine samples to explore epigenetic alterations.

RESULTS

A heterozygous splicing site variant, SLCO2A1:c.940 + 1G > A, was detected in both patients. To explore the possible involvement of epigenetic alterations, we analyzed protein and messenger RNA expression of SLCO2A1, and observed attenuated SLCO2A1 expression in the inflamed lesions of these patients compared with that in the control individuals. Furthermore, bisulfite sequencing indicated dense methylation in the promoter region of SLCO2A1 only in the inflamed lesions of both patients. The urinary PG metabolite levels in these patients were comparable to those in patients with chronic enteropathy associated with SLCO2A1 and higher than those in the control individuals. We found considerably higher levels of the metabolites in patient 1, who showed more severe symptoms than patient 2.

CONCLUSIONS

Local DNA methylation attenuated SLCO2A1 expression, which may evoke local inflammation of the mucosa by the unincorporated PG. These findings may improve our understanding of the epigenetic mechanisms underlying IBD development.