The Significance of Bile in the Biliopancreatic Limb on Metabolic Improvement After Duodenal-Jejunal Bypass

INTRODUCTION

Duodenal-jejunal bypass (DJB) is an experimental procedure in metabolic surgery that does not have a restrictive component. Changes in bile acid (BA) dynamics and intestinal microbiota are possibly related to metabolic improvement after DJB. Our previous studies involving obese diabetic rats showed the crucial role of the biliopancreatic limb (BPL) in metabolic improvement after DJB caused by BA reabsorption. We established a new DJB procedure to prevent bile from flowing into the BPL and aimed to elucidate the importance of bile in the BPL after DJB.

METHODS

Otsuka Long-Evans Tokushima Fatty rats with diabetes were divided into three groups: two DJB groups and a sham group (n = 11). Duodenal-jejunal anastomosis was performed proximal to the papilla of Vater in the DJB group (n = 11). However, the DJB-D group (n = 11) underwent a new procedure with duodenal-jejunal anastomosis distal to the papilla of Vater for preventing bile flow into the BPL.

RESULTS

Glucose metabolism improved and weight gain was suppressed in the DJB group, but not in the DJB-D and sham groups. Serum BA level and conjugated BA concentration were elevated in the DJB group. The gut microbiota was altered only in the DJB group; the abundance of Firmicutes and Bacteroidetes decreased and that of Actinobacteria increased. However, the DJB-D group exhibited no apparent change in the gut microbiota, similar to the sham group.

CONCLUSION

BAs are essential in the BPL for metabolic improvement after DJB; they can improve the gut microbiota in these processes.

Accelerated plasma-cell differentiation in Bach2-deficient mouse B cells is caused by altered IRF4 functions

Transcription factors BACH2 and IRF4 are both essential for antibody class-switch recombination (CSR) in activated B lymphocytes, while they oppositely regulate the differentiation of plasma cells (PCs). Here, we investigated how BACH2 and IRF4 interact during CSR and plasma-cell differentiation. We found that BACH2 organizes heterochromatin formation of target gene loci in mouse splenic B cells, including targets of IRF4 activation such as Aicda, an inducer of CSR, and Prdm1, a master plasma-cell regulator. Release of these gene loci from heterochromatin in response to B-cell receptor stimulation was coupled to AKT-mTOR pathway activation. In Bach2-deficient B cells, PC genes' activation depended on IRF4 protein accumulation, without an increase in Irf4 mRNA. Mechanistically, a PU.1-IRF4 heterodimer in activated B cells promoted BACH2 function by inducing gene expression of Bach2 and Pten, a negative regulator of AKT signaling. Elevated AKT activity in Bach2-deficient B cells resulted in IRF4 protein accumulation. Thus, BACH2 and IRF4 mutually modulate the activity of each other, and BACH2 inhibits PC differentiation by both the repression of PC genes and the restriction of IRF4 protein accumulation.

Intracanal microbiome profiles of two apical periodontitis cases in one patient: A comparison with saliva and plaque profiles

OBJECTIVES

To determine the characteristics of the endodontic microbiome.

MATERIAL AND METHODS

Saliva, plaque, and infected root canal wall dentin of two teeth suffering from apical periodontitis were harvested from a 58-year-old man. Bacterial DNA was extracted from each sample, and 16S rRNA gene analysis targeting the V3-V4 region was conducted on the Illumina MiSeq platform using QIIME2. The functional potential of the microbiomes was inferred using PICRUSt2.

RESULTS

The four microbiomes were different in structure and membership, yet the nine most abundant metabolic pathways were common among them. The two endodontic microbiomes were more anaerobic, rich in Firmicutes, and scarce in Actinobacteriota and Proteobacteria, compared with saliva and plaque microbiomes. Their profiles were dissimilar despite their clinical and radiographic similarities.

CONCLUSIONS

The endodontic microbiomes were anaerobic, rich in Firmicutes, scarce in Actinobacteriota and Proteobacteria, and considerably varied within an individual.

Progress report of the Tohoku Medical Megabank Community-Based Cohort Study: Study profile of the repeated center-based survey during second period in Miyagi Prefecture

BACKGROUND

The purpose of this study was to report the basic profile of the Miyagi Prefecture part of a repeated center-based survey during the second period (2nd period survey) of the Tohoku Medical Megabank Community-Based Cohort Study (TMM CommCohort Study), as well as the participants' characteristics based on their participation type in the baseline survey.

METHODS

The 2nd period survey, conducted from June 2017 to March 2021, included participants of the TMM CommCohort Study (May 2013 to March 2016). In addition to the questionnaire, blood, urine, and physiological function tests were performed during the 2nd period survey. There were three main ways of participation in the baseline survey: Type 1, Type 1 additional, or Type 2 survey. The 2nd period survey was conducted in the same manner as the Type 2 survey, which was based on the community support center (CSC).

RESULTS

In Miyagi Prefecture, 29,383 (57.7%) of 50,967 participants participated in the 2nd period survey. The participation rate among individuals who had visited the CSC was approximately 80%. Although some factors differed depending on the participation type in the baseline survey, the 2nd period survey respondents in the Type 1 and Type 2 survey groups at baseline had similar traits.

CONCLUSIONS

The 2nd period survey of the TMM CommCohort Study provided detailed follow-up information. Following up on the health conditions of the participants will clarify the long-term effects of disasters and contribute to personalized prevention.

Design and Progress of Child Health Assessments at Community Support Centers in the Birth and Three-Generation Cohort Study of the Tohoku Medical Megabank Project

The Tohoku Medical Megabank Project (TMM) has been conducting a birth and three-generation cohort study (the BirThree Cohort Study). We recruited 73,529 pregnant women and their family members for this cohort study, which included 23,143 newborns and 9,459 of their siblings. We designed and are in the process of conducting three-step health assessments for each newborn at approximately ages of 5, 10 and 16. These health assessments are administered at seven community support centers. Trained genome medical research coordinators conduct physical examinations of and collect biological specimens from each participant. The Sendai Children's Health Square has been established as the headquarters for these child health assessments and is utilized to accumulate knowledge that can facilitate the proper practice of child health assessments. We designed all the relevant health assessments facilities to allow parents and their children to participate in the health assessments concomitantly. Our centers serve as places where child participants and their parents can feel at ease as a result of the implementation of safety measures and child hospitality measures. The TMM BirThree Cohort Study is in the process of conducting strategically detailed health assessments and genome analysis, which can facilitate studies concerning the gene-environment interactions relevant to noncommunicable diseases. Through these operations, our study allows for a significant depth of data to be collected in terms of the number of biospecimens under study and the comprehensiveness of both basic and clinical data alongside relevant family information.

Phenotype Harmonization in the GLIDE2 Oral Health Genomics Consortium

Genetic risk factors play important roles in the etiology of oral, dental, and craniofacial diseases. Identifying the relevant risk loci and understanding their molecular biology could highlight new prevention and management avenues. Our current understanding of oral health genomics suggests that dental caries and periodontitis are polygenic diseases, and very large sample sizes and informative phenotypic measures are required to discover signals and adequately map associations across the human genome. In this article, we introduce the second wave of the Gene-Lifestyle Interactions and Dental Endpoints consortium (GLIDE2) and discuss relevant data analytics challenges, opportunities, and applications. In this phase, the consortium comprises a diverse, multiethnic sample of over 700,000 participants from 21 studies contributing clinical data on dental caries experience and periodontitis. We outline the methodological challenges of combining data from heterogeneous populations, as well as the data reduction problem in resolving detailed clinical examination records into tractable phenotypes, and describe a strategy that addresses this. Specifically, we propose a 3-tiered phenotyping approach aimed at leveraging both the large sample size in the consortium and the detailed clinical information available in some studies, wherein binary, severity-encompassing, and "precision," data-driven clinical traits are employed. As an illustration of the use of data-driven traits across multiple cohorts, we present an application of dental caries experience data harmonization in 8 participating studies (N = 55,143) using previously developed permanent dentition tooth surface-level dental caries pattern traits. We demonstrate that these clinical patterns are transferable across multiple cohorts, have similar relative contributions within each study, and thus are prime targets for genetic interrogation in the expanded and diverse multiethnic sample of GLIDE2. We anticipate that results from GLIDE2 will decisively advance the knowledge base of mechanisms at play in oral, dental, and craniofacial health and disease and further catalyze international collaboration and data and resource sharing in genomics research.

Dental care using an oral appliance to support hematopoietic stem cell transplantation for NK/T cell lymphoma, nasal type, with palatal perforation

PATIENT

A 33-year-old man diagnosed with extranodal natural killer cell/T-cell lymphoma, nasal type (ENKTCL-NT) inducing palatal perforation was referred to the perioperative oral care support center of Tohoku University Hospital for dental care to support cancer treatment including chemotherapy and hematopoietic stem cell transplantation (HSCT). Dental review during chemotherapy revealed mucositis suspected to be caused by mucosal trauma from altered jaw function (chewing and speech) due to palatal perforation. Although the patient was already in the cleanroom, an oral appliance as well as conservative care as recommended in oral management guidelines for HSCT were used to prevent worsening of oral mucositis at subsequent HSCT including High-dose chemotherapy and total body irradiation. After HSCT, a prosthodontist fitted a palatal obturator made by a dental technician and an oral surgeon reviewed the necrotic bone and removed the sequestra according to the changes in the palate. This approach involving a multidisciplinary team including a hematologist improved the impaired oral function and minimized oral complications .

DISCUSSION

ENKTCL-NT and its treatment have a significant impact on patients' oral status. Hence, it is important to provide customized dental care based on previously endorsed guidelines according to the type of disease, treatment requirements, and oral and systemic status.

CONCLUSIONS

This report indicated the importance of dental care with a customized plan before, during, and after HSCT for ENKTCL-NT with multidisciplinary supportive care for cancer patients to improve the impaired oral function and to minimize oral complications.

Design and Progress of Oral Health Examinations in the Tohoku Medical Megabank Project

In order to assess the long-term impact of the Great East Japan Earthquake on the oral health of disaster victims and to evaluate gene-environmental interactions in the development of major oral diseases and oral-systemic associations, the oral part of two large-scale genome cohort studies by the Tohoku Medical Megabank Organization (ToMMo), including the Community-based cohort (CommCohort) study and the Birth and Three-Generation cohort (BirThree) study, have been conducted. The study population comprised 32,185 subjects, including 16,886 participants in the CommCohort study and 15,299 participants in the BirThree cohort study, recruited from 2013 to 2017. The oral studies consist of a questionnaire regarding oral hygiene behavior, clinical examinations by dentists, and oral plaque and saliva sampling for microbiome analyses, which were carried out at seven community support centers in Miyagi prefecture. The median age of all participants was 55.0 years, and 66.1% of participants were women. Almost all participants reported that they brushed their teeth more than once a day. The median number of present teeth was 27.0, and the decayed, missing and filled tooth number was 16.0, with a significant difference according to age and sex. The median periodontal pocket and clinical attachment level was 2.48 mm and 4.00 mm, respectively. Periodontal parameters increased significantly according to age, except for the accumulation of dental calculus. The oral part of these extensive cross-sectional studies provides a unique and important platform for future studies on oral health and diseases that elicit through interactions with systemic diseases, lifestyles, life events and genetic backgrounds, and contributes to researches clarifying the long-term effects of disasters on oral health.

Oral Microbiome Analysis in Prospective Genome Cohort Studies of the Tohoku Medical Megabank Project

A baseline oral microbiome study of the Tohoku Medical Megabank Organization (TMM) was planned to characterize the profile of the oral microbiome in the Japanese population. The study also aimed to clarify risk factors for multifactorial diseases by integrated analysis of the oral microbiome and host genome/omics information. From 2013 to 2016, we collected three types of oral biospecimens, saliva, supragingival plaque, and tongue swab, from a total of 25,101 participants who had a dental examination in TMM. In this study, we used two independent cohorts; the Community-Based Cohort and Birth and Three-Generation Cohort as discovery and validation cohorts, respectively, and we selected participants examined by a single dentist. We found through the 16S ribosomal RNA gene sequencing analysis of 834 participants of the Community-Based Cohort Study that there are differences in the microbial composition and community structure between saliva and plaque. The species diversities in both saliva and plaque were increased in correlation with the severity of periodontal disease. These results were nicely reproduced in the analysis of 455 participants of the Birth and Three-Generation Cohort Study. In addition, strong positive and negative associations of microbial taxa in both plaque and saliva with periodontitis-associated biofilm formation were detected by co-occurrence network analysis. The classes Actinobacteria and Bacilli, including oral health-associated bacterial species, showed a positive correlation in saliva. These results revealed differences in microbial composition and community structure between saliva and plaque and a correlation between microbial species and the severity of periodontal disease. We expect that the large database of the oral microbiome in the TMM biobank will help in the discovery of novel targets for the treatment and prevention of oral diseases, as well as for the discovery of therapeutic and/or preventive targets of systemic diseases.

The Transcription Factor Bach2 Is Phosphorylated at Multiple Sites in Murine B Cells but a Single Site Prevents Its Nuclear Localization

The transcription factor Bach2 regulates the immune system at multiple points, including class switch recombination (CSR) in activated B cells and the function of T cells in part by restricting their terminal differentiation. However, the regulation of Bach2 expression and its activity in the immune cells are still unclear. Here, we demonstrated that Bach2 mRNA expression decreased in Pten-deficient primary B cells. Bach2 was phosphorylated in primary B cells, which was increased upon the activation of the B cell receptor by an anti-immunoglobulin M (IgM) antibody or CD40 ligand. Using specific inhibitors of kinases, the phosphorylation of Bach2 in activated B cells was shown to depend on the phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway. The complex of mTOR and Raptor phosphorylated Bach2 in vitro. We identified multiple new phosphorylation sites of Bach2 by mass spectrometry analysis of epitope-tagged Bach2 expressed in the mature B cell line BAL17. Among the sites identified, serine 535 (Ser-535) was critical for the regulation of Bach2 because a single mutation of Ser-535 abolished cytoplasmic accumulation of Bach2, promoting its nuclear accumulation in pre-B cells, whereas Ser-509 played an auxiliary role. Bach2 repressor activity was enhanced by the Ser-535 mutation in B cells. These results suggest that the PI3K-Akt-mTOR pathway inhibits Bach2 by both repressing its expression and inducing its phosphorylation in B cells.