Oral Exposure to Polystyrene Microplastics of Mice on a Normal or High-Fat Diet and Intestinal and Metabolic Outcomes

マイクロプラスチックの経口摂取が高脂肪食条件下での代謝障害を悪化させる. 京都大学プレスリリース. 2023-02-24.[Background:] Microplastics (MPs) are small particles of plastic (≤ 5mm in diameter). In recent years, oral exposure to MPs in living organisms has been a cause of concern. Leaky gut syndrome (LGS), associated with a high-fat diet (HFD) in mice, can increase the entry of foreign substances into the body through the intestinal mucosa. [Objectives:] We aimed to evaluate the pathophysiology of intestinal outcomes associated with consuming a high-fat diet and simultaneous intake of MPs, focusing on endocrine and metabolic systems. [Methods:] C57BL6/J mice were fed a normal diet (ND) or HFD with or without polystyrene MP for 4 wk to investigate differences in glucose tolerance, intestinal permeability, gut microbiota, as well as metabolites in serum, feces, and liver. [Results:] In comparison with HFD mice, mice fed the HFD with MPs had higher blood glucose, serum lipid concentrations, and nonalcoholic fatty liver disease (NAFLD) activity scores. Permeability and goblet cell count of the small intestine (SI) in HFD-fed mice were higher and lower, respectively, than in ND-fed mice. There was no obvious difference in the number of inflammatory cells in the SI lamina propria between mice fed the ND and mice fed the ND with MP, but there were more inflammatory cells and fewer anti-inflammatory cells in mice fed the HFD with MPs in comparison with mice fed the HFD without MPs. The expression of genes related to inflammation, long-chain fatty acid transporter, and Na⁺/glucose cotransporter was significantly higher in mice fed the HFD with MPs than in mice fed the HFD without MPs. Furthermore, the genus Desulfovibrio was significantly more abundant in the intestines of mice fed the HFD with MPs in comparison with mice fed the HFD without MPs. Muc2 gene expression was decreased when palmitic acid and microplastics were added to the murine intestinal epithelial cell line MODE-K cells, and Muc2 gene expression was increased when IL-22 was added. [Discussion:] Our findings suggest that in this study, MP induced metabolic disturbances, such as diabetes and NAFLD, only in mice fed a high-fat diet. These findings suggest that LGS might have been triggered by HFD, causing MPs to be deposited in the intestinal mucosa, resulting in inflammation of the intestinal mucosal intrinsic layer and thereby altering nutrient absorption. These results highlight the need for reducing oral exposure to MPs through remedial environmental measures to improve metabolic disturbance under high-fat diet conditions

Frequent Usage of Convenience Stores is Associated with Low Diet Quality

Previous studies have revealed that the density of convenience stores in the neighborhood was associated with chronic diseases. In Japan, convenience stores are more common, and it is thus more important to assess whether people use convenience stores than the density or availability of the convenience stores. In this cross-sectional study of patients with type 2 diabetes, the association between the usage of the convenience stores and dietary habits or the prevalence of hypertension was evaluated. Among the 206 men and 161 women in the study, 24 men and 9 women used convenience stores three or more times per week. Fruit and vegetable intake (men, 132 (102−191) vs. 192 (128−267) g/1000 kcal, p = 0.019; and women, 178 (132−207) vs. 239 (172−313) g/1000 kcal, p = 0.063) of patients who frequently use convenience stores was lower compared to those who did not. Net endogenous acid production score (men, 55.2 (45.4−65.2) vs. 48.9 (42.3−56.8) mEq/day, p = 0.013; and women, 56.9 (52.6−59.8) vs. 46.3 (40.9−54.0) mEq/day, p = 0.050) and intake of carbohydrate to fiber ratio (men, 21.5 (20.0−29.3) vs. 19.9 (15.7−25.0), p = 0.052; and women, 21.0 (18.9−23.9) vs. 16.2 (13.8−20.3), p = 0.017) of patients who frequently use convenience stores were higher compared to those who did not. Additionally, frequent usage of convenience stores was associated with the prevalence of hypertension after adjusting for covariates (5.01; 95% confidence interval, 1.12−22.50; p = 0.035). In conclusion, frequent usage of convenience stores is associated with low diet quality and the prevalence of hypertension

Milk protects against sarcopenic obesity due to increase in the genus Akkermansia in faeces of db/db mice

Abstract Background Sarcopenic obesity, a combination of sarcopenia and obesity, is a pathological feature of type 2 diabetes. Several human studies have shown that milk is useful in the prevention of sarcopenia. This study was aimed at clarifying the effect of milk on the prevention of sarcopenic obesity in db/db mice. Methods A randomized and investigator‐blinded study was conducted using male db/db mice. Eight‐week‐old db/db mice were housed for 8 weeks and fed milk (100 μL/day) using a sonde. The faecal microbiota transplantation (FMT) group received antibiotics for 2 weeks, starting at 6 weeks of age, followed by FMT twice a week until 16 weeks of age. Results Milk administration to db/db mice increased grip strength (Milk−: 164.2 ± 4.7 g, Milk+: 230.2 ± 56.0 g, P = 0.017), muscle mass (soleus muscle, Milk−: 164.2 ± 4.7 mg, Milk+: 230.2 ± 56.0 mg, P < 0.001; plantaris muscle, Milk−: 13.3 ± 1.2 mg, Milk+: 16.0 ± 1.7 mg, P < 0.001) and decreased visceral fat mass (Milk−: 2.39 ± 0.08 g, Milk+: 1.98 ± 0.04 mg, P < 0.001), resulting in a significant increase in physical activity (light: P = 0.013, dark: P = 0.034). FMT from mice fed milk not only improved sarcopenic obesity but also significantly improved glucose intolerance. Microarray analysis of gene expression in the small intestine revealed that the expression of amino acid absorption transporter genes, namely, SIc7a5 (P = 0.010), SIc7a1 (P = 0.015), Ppp1r15a (P = 0.041) and SIc7a11 (P = 0.029), was elevated in mice fed milk. In 16S rRNA sequencing of gut microbiota, the genus Akkermansia was increased in both the mice fed milk and the FMT group from the mice fed milk. Conclusions The findings of this study suggest that besides increasing the intake of nutrients, such as amino acids, milk consumption also changes the intestinal environment, which might contribute to the mechanism of milk‐induced improvement of sarcopenic obesity

Characterization of Peripheral Blood TCR in Patients with Type 1 Diabetes Mellitus by BD RhapsodyTM VDJ CDR3 Assay

The sequence of complementarity-determining region 3 of the T-cell receptor (TCR) varies widely due to the insertion of random bases during V-(D)-J recombination. In this study, we used single-cell VDJ sequencing using the latest technology, BD Rhapsody, to identify the TCR sequences of autoreactive T-cells characteristic of Japanese type 1 diabetes mellitus (T1DM) and to clarify the pairing of TCR of peripheral blood mononuclear cells from four patients with T1DM at the single-cell level. The expression levels of the TCR alpha variable (TRAV) 17 and TRAV21 in T1DM patients were higher than those in healthy Japanese subjects. Furthermore, the Shannon index of CD8+ T cells and FOXP3+ cells in T1DM patients was lower than that of healthy subjects. The gene expression of PRF1, GZMH, ITGB2, NKG7, CTSW, and CST7 was increased, while the expression of CD4, CD7, CD5, HLA-A, CD27, and IL-32 was decreased in the CD8+ T cells of T1DM patients. The upregulated gene expression was IL4R and TNFRSF4 in FOXP3+ cells of T1DM patients. Overall, these findings demonstrate that TCR diversity and gene expression of CD8+ and FOXP3+ cells are different in patients with T1DM and healthy subjects

Usefulness of Aerobic Exercise for Home Blood Pressure Control in Patients with Diabetes: Randomized Crossover Trial

Hypertension usually coexists with diabetes mellitus and significantly increases the risk of macrovascular complications. Blood pressure measured at home, especially nocturnal blood pressure, is particularly important because it is more strongly associated with target organ damage than clinical blood pressure measurements. Regular moderate aerobic exercise has been shown to have anti-hypertensive effects. This study aimed to investigate the effects of aerobic exercise on home blood pressure in patients with diabetes. This randomized crossover trial was based on outpatient treatment at a university hospital. In this randomized crossover trial, 124 patients with type 2 diabetes were randomly assigned to two groups over 56 days: an exercise preceding group (exercise intervention for 28 days and then no exercise intervention for the following 28 days) and an exercise lagging group (no exercise intervention for 28 days and then exercise intervention for the following 28 days). The associations between the nocturnal blood pressure and exercise intervention were assessed accordingly. A decrease in blood pressure was observed in the morning and evening, at 2 a.m. and 3 a.m. after exercise intervention; however, there was no significant difference between groups. Moderate exercise was not effective in lowering nocturnal blood pressure in this study

Reasons for Discontinuing Treatment with Sodium-Glucose Cotransporter 2 Inhibitors in Patients with Diabetes in Real-World Settings: The KAMOGAWA-A Study

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) are a class of antidiabetic agents known to exert cardioprotective, renoprotective, and hypoglycemic effects. However, these agents have been associated with adverse effects, such as genital infection, volume depletion, hypoglycemia, and diabetic ketoacidosis, resulting in drug discontinuation. Herein, we aimed to determine the reasons for discontinuing treatment with SGLT2is among Japanese patients with diabetes. This retrospective cohort study enrolled 766 patients with diabetes who had initiated SGLT2is between January 2014 and September 2021. The follow-up period was 2 years from the initiation of the SGLT2is. Overall, 97 patients (12.7%) discontinued the SGLT2is during the follow-up period. The most common reasons for discontinuing the SGLT2is were frequent urination (19.6%), followed by genital infection (11.3%), improved glycemic control (10.6%), and renal dysfunction (8.2%). A comparison of the characteristics between the continuation and the discontinuation group was conducted, excluding those who discontinued the SGLT2is because of improved glycemic control. The patients in the discontinuation group (68 [55–75] years) were older than those in the continuation group (64 [53–71] years; p = 0.003). Importantly, we found no significant association between diabetes duration, diabetic control, renal function, or complications of diabetes in both groups. This real-world study revealed that frequent urination was the most common reason underlying SGLT2i discontinuation among Japanese patients with diabetes. To avoid discontinuation, precautions against various factors that may cause frequent urination must be implemented

Eating Speed Is Associated with the Presence of Sarcopenia in Older Patients with Type 2 Diabetes: A Cross-Sectional Study of the KAMOGAWA-DM Cohort

To determine the relationship between eating speed and the presence of sarcopenia in older patients with type 2 diabetes (T2D), in this cross-sectional study, patient eating speeds were classified as “fast-”, “normal-” and “slow-speed eating.” A multifrequency impedance analyzer was used to evaluate patient body compositions. Sarcopenia was defined as having both low muscle strength, a handgrip strength 2 for men and 2 for women. Among 239 individuals, the frequencies of fast-, normal-, and slow-speed eating were 47.3%, 32.2%, and 20.5%, respectively; and the prevalence of sarcopenia was 15.9%. Patients with a slow eating speed had greater prevalence of low skeletal muscle mass, low muscle strength, and sarcopenia than those with a fast or normal eating speed. After adjusting for covariates, compared to slow eaters, the odds ratio of having sarcopenia among fast- and normal-speed eaters was 0.31 [95% CI: 0.12–0.80] and 0.18 [95% CI: 0.06–0.53], respectively. Having a slow eating speed is associated with a heightened risk of sarcopenia in older patients with T2D

Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with Glycemic Variability in Patients with Type 2 Diabetes: A Cross-Sectional Study

Glycemic control, including glycemic variability, is important for the prevention of diabetic vascular complications in patients with type 2 diabetes mellitus (T2DM). There was an association between miso soup intake and insulin resistance. However, the relationship between habitual miso consumption and glycemic control, including glycemic variability, in patients with T2DM remains unknown. We defined people without habitual miso consumption if they did not consume miso soup at all in a day. The average, standard deviation (SD), and coefficient of variation (CV), calculated as CV = (SD/average HbA1c) × 100 (%), of hemoglobin (Hb) A1c levels were evaluated. The proportions of habitual miso consumption of male and female were 88.1% and 82.3%, respectively. The average (7.0 [6.4–7.5] vs. 7.3 [6.8–8.4] %, p = 0.009), SD (0.21 [0.12–0.32] vs. 0.37 [0.20–0.72], p = 0.004), and CV (0.03 [0.02–0.04] vs. 0.05 [0.03–0.09], p = 0.005) of HbA1c levels in female with habitual miso consumption were lower than those of female without. Moreover, habitual miso consumption correlated with average (β = −0.251, p = 0.009), SD (β = −0.175, p = 0.016), and CV (β = −0.185, p = 0.022) of HbA1c levels after adjusting for covariates. However, no association between habitual miso consumption and any glycemic parameters was shown among male. This study clarified the association between habitual miso consumption and good glycemic control, including glycemic variability, in female, but not in male

The Effects of Metformin on the Gut Microbiota of Patients with Type 2 Diabetes: A Two-Center, Quasi-Experimental Study

Metformin is reported to affect human gut microbiota; however, the nature of this association in Japanese patients with type 2 diabetes mellitus (T2DM) is unknown. We enrolled 31 patients with T2DM who took metformin for the first time in this study. We compared them before and after four weeks of taking metformin. Fecal samples were collected and 16S rDNA sequences were performed to identify the gut microbiota. Blood samples and Gastrointestinal Symptom Rating Scale (GSRS) questionnaire results, denoting gastro-intestinal symptoms, were also collected. In the whole-group analysis, no significant differences were found at the phylum level. In a subgroup of 21 patients that excluding those using medications affecting gut microbiota, there was a significant decrease of the phylum Firmicutes (p = 0.042) and of the ratio of the Firmicutes and Bacteroidetes abundances (p = 0.04) after taking metformin. Changes in abdominal pain (r = &minus;0.56, p = 0.008) and regurgitation (r = &minus;0.53, p = 0.01) were associated with Parabacteroides. Despite there being no direct association with abdominal symptoms, our study revealed that the composition of gut microbiota in Japanese individuals with T2DM partially changed after starting metformin