大橋 鉱二

BACKGROUND: Incidence of ischemic stroke increased after natural disasters. Therefore, it is important to establish a means of identifying high-risk populations for incident stroke. We performed a prospective cohort study to examine whether these three cardiovascular disease-related miRNAs (miR-126, miR-197, and miR-223) are associated with incident stroke among elderly survivors of the Great East Japan Earthquake. METHOD: This cohort study was conducted using the data of 1192 survivors of the Great East Japan Earthquake over 60-years old who underwent a health check-up in December 2011. We followed up participants to record stroke cases until the end of 2016. We measured serum miRNAs by quantitative real-time polymerase chain reaction. HRs for incident stroke were estimated by Cox proportional hazard regression analyses. RESULT: The serum miR-197 level was significantly associated with the incident stroke; the HR per one standard deviation change in the miR-197 level was 1.65 (95% confidence interval: 1.19 - 2.30). In contrast, the levels of miR-126 and miR-223 were not associated with the incident stroke. CONCLUSION: We found that a higher miR-197 level is associated with an increased risk of incident stroke; thus, miR-197 is expected to be useful as a predictive biomarker.

Nutritional researches have successfully used animal models to gain new insights into nutrient action. However, comprehensive descriptions of their molecular mechanisms of action remain elusive as appropriate in vitro evaluation systems are lacking. Organoid models can mimic physiological structures and reproduce in vivo functions, making them increasingly utilized in biomedical research for a better understand physiological and pathological phenomena. Therefore, organoid modeling can be a powerful approach for to understand the molecular mechanisms of nutrient action. The present study aims to demonstrate the utility of organoids in nutritional research by further investigating the molecular mechanisms responsible for the negative effects of fructose intake using liver organoids. Here, we treated liver organoids with fructose and analyzed their gene expression profiles and DNA methylation levels. Microarray analysis demonstrated that fructose-treated organoids exhibited increased selenoprotein p (Sepp1) gene expression, whereas pyrosequencing assays revealed reduced DNA methylation levels in the Sepp1 region. These results were consistent with observations using hepatic tissues from fructose-fed rats. Conversely, no differences in Sepp1 mRNA and DNA methylation levels were observed in two-dimensional cells. These results suggest that organoids serve as an ideal in vitro model to recapitulate in vivo tissue responses and help to validate the molecular mechanisms of nutrient action compared to conventional cellular models.

Thioredoxin-interacting protein (TXNIP) plays an important role in glucose metabolism, and its expression is regulated by DNA methylation (DNAm). Although the association between TXNIP DNAm and type 2 diabetes mellitus has been demonstrated in studies with a cross-sectional design, prospective studies are needed. We therefore examined the association between TXNIP DNAm levels and longitudinal changes in glycemic traits by conducting a longitudinal study involving 169 subjects who underwent two health checkups in 2015 and 2019. We used a pyrosequencing assay to determine TXNIP DNAm levels in leukocytes (cg19693031). Logistic regression analyses were performed to assess the associations between dichotomized TXNIP DNAm levels and marked increases in glycemic traits. At four years, the TXNIP DNA hypomethylation group had a higher percentage of changes in fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) compared to those in the hypermethylation group. The adjusted odds ratios for FPG and HbA1c levels were significantly higher in the TXNIP DNA hypomethylation group than in the hypermethylation group. We found that TXNIP DNA hypomethylation at baseline was associated with a marked increase in glycemic traits. Leukocyte TXNIP DNAm status could potentially be used as an early biomarker for impaired glucose homeostasis.