Effects of Consuming Xylitol on Gut Microbiota and Lipid Metabolism in Mice

The sugar alcohol xylitol inhibits the growth of some bacterial species including Streptococcus mutans. It is used as a food additive to prevent caries. We previously showed that 1.5–4.0 g/kg body weight/day xylitol as part of a high-fat diet (HFD) improved lipid metabolism in rats. However, the effects of lower daily doses of dietary xylitol on gut microbiota and lipid metabolism are unclear. We examined the effect of 40 and 200 mg/kg body weight/day xylitol intake on gut microbiota and lipid metabolism in mice. Bacterial compositions were characterized by denaturing gradient gel electrophoresis and targeted real-time PCR. Luminal metabolites were determined by capillary electrophoresis electrospray ionization time-of-flight mass spectrometry. Plasma lipid parameters and glucose tolerance were examined. Dietary supplementation with low- or medium-dose xylitol (40 or 194 mg/kg body weight/day, respectively) significantly altered the fecal microbiota composition in mice. Relative to mice not fed xylitol, the addition of medium-dose xylitol to a regular and HFD in experimental mice reduced the abundance of fecal Bacteroidetes phylum and the genus Barnesiella, whereas the abundance of Firmicutes phylum and the genus Prevotella was increased in mice fed an HFD with medium-dose dietary xylitol. Body composition, hepatic and serum lipid parameters, oral glucose tolerance, and luminal metabolites were unaffected by xylitol consumption. In mice, 40 and 194 mg/kg body weight/day xylitol in the diet induced gradual changes in gut microbiota but not in lipid metabolism

ABCA1 gene-physical activity interaction for HDL-C

Few studies have investigated the interactions between HDL-C-related SNPs identified by genome-wide association (GWA) study and physical activity (PA) on HDL-C. First, we conducted a sex-stratified GWA study in a discovery sample (2,231 men and 2,431 women) and replication sample (2,599 men and 3,109 women) to identify SNPs influencing log-transformed HDL-C in Japanese participants in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. We also replicated previously reported HDL-C-related SNPs in a combined (discovery plus replication) sample (4,830 men and 5,540 women). We then analyzed the interactions of the HDL-C-related SNPs with PA on HDL-C. The sex-stratified GWA analyses identified 11 and 10 HDL-C-related SNPs in men and women as targets for an interaction analysis. Among these, only one interaction of ABCA1 rs1883025 with PA was statistically significant in men, after Bonferroni correction [P-interaction = 0.001 (α = 0.05/21 = 0.002)]. The per-major-allele (C allele) increase in log-transformed HDL-C was lost in men with low PA (β = 0.008) compared with those with medium (β = 0.032) or high PA (β = 0.034). These findings suggest that the benefit of carrying a C allele of ABCA1 rs1883025 on enhancing HDL-C may be attenuated in inactive men

Fluorescence and Bioluminescence Imaging of Angiogenesis in Flk1-Nano-lantern Transgenic Mice

Angiogenesis is important for normal development as well as for tumour growth. However, the molecular and cellular mechanisms underlying angiogenesis are not fully understood, partly because of the lack of a good animal model for imaging. Here, we report the generation of a novel transgenic (Tg) mouse that expresses a bioluminescent reporter protein, Nano-lantern, under the control of Fetal liver kinase 1 (Flk1). Flk1-Nano-lantern BAC Tg mice recapitulated endogenous Flk1 expression in endothelial cells and lymphatic endothelial cells during development and tumour growth. Importantly, bioluminescence imaging of endothelial cells from the aortic rings of Flk1-Nano-lantern BAC Tg mice enabled us to observe endothelial sprouting for 18 hr without any detectable phototoxicity. Furthermore, Flk1-Nano-lantern BAC Tg mice achieved time-lapse luminescence imaging of tumour angiogenesis in freely moving mice with implanted tumours. Thus, this transgenic mouse line contributes a unique model to study angiogenesis within both physiological and pathological contexts

Genome-wide meta-analysis identifies multiple novel loci associated with serum uric acid levels in Japanese individuals

Gout is a common arthritis caused by elevated serum uric acid (SUA) levels. Here we investigated loci influencing SUA in a genome-wide meta-analysis with 121,745 Japanese subjects. We identified 8948 variants at 36 genomic loci (P<5 × 10–8) including eight novel loci. Of these, missense variants of SESN2 and PNPLA3 were predicted to be damaging to the function of these proteins; another five loci—TMEM18, TM4SF4, MXD3-LMAN2, PSORS1C1-PSORS1C2, and HNF4A—are related to cell metabolism, proliferation, or oxidative stress; and the remaining locus, LINC01578, is unknown. We also identified 132 correlated genes whose expression levels are associated with SUA-increasing alleles. These genes are enriched for the UniProt transport term, suggesting the importance of transport-related genes in SUA regulation. Furthermore, trans-ethnic meta-analysis across our own meta-analysis and the Global Urate Genetics Consortium has revealed 15 more novel loci associated with SUA. Our findings provide insight into the pathogenesis, treatment, and prevention of hyperuricemia/gout

The sustained psychological impact of coronavirus disease 2019 pandemic on hospital workers 2 years after the outbreak: a repeated cross-sectional study in Kobe

Abstract Background Healthcare workers who are exposed to coronavirus disease 2019 are psychologically distressed. This study aimed to evaluate the mental health outcomes of hospital workers 2 years after the outbreak of coronavirus disease 2019 and to identify changes in the stress of hospital workers and predicted risk factors. Methods This survey was conducted 2 years after the initial evaluation performed under the first emergency declaration of the coronavirus disease 2019 pandemic among hospital workers at the same hospital in an ordinance-designated city in Japan from June to July 2022. Sociodemographic data, 19 stress-related question responses, the Impact of Event Scale-Revised, and the Maslach burnout inventory-general survey were collected. Multiple regression models were used to identify factors associated with each of the mental health outcomes 2 years after the coronavirus disease 2019 outbreak. Results We received 719 valid responses. Between 2020 and 2022, hospital workers’ anxiety about infection decreased, whereas their exhaustion and workload increased. Multiple regression analysis revealed that 2 years after the coronavirus disease 2019 outbreak, nurses and young people were at a higher risk of experiencing stress and burnout due to emotional exhaustion, respectively. Conclusions This is the first study to examine the long-term stress of hospital workers measured in Japan. Exhaustion and workload were worsened 2 years into the pandemic. Therefore, health and medical institutions should continuously monitor the physical and psychological health of staff members

Effects of Consuming Xylitol on Gut Microbiota and Lipid Metabolism in Mice

The sugar alcohol xylitol inhibits the growth of some bacterial species including Streptococcus mutans. It is used as a food additive to prevent caries. We previously showed that 1.5–4.0 g/kg body weight/day xylitol as part of a high-fat diet (HFD) improved lipid metabolism in rats. However, the effects of lower daily doses of dietary xylitol on gut microbiota and lipid metabolism are unclear. We examined the effect of 40 and 200 mg/kg body weight/day xylitol intake on gut microbiota and lipid metabolism in mice. Bacterial compositions were characterized by denaturing gradient gel electrophoresis and targeted real-time PCR. Luminal metabolites were determined by capillary electrophoresis electrospray ionization time-of-flight mass spectrometry. Plasma lipid parameters and glucose tolerance were examined. Dietary supplementation with low- or medium-dose xylitol (40 or 194 mg/kg body weight/day, respectively) significantly altered the fecal microbiota composition in mice. Relative to mice not fed xylitol, the addition of medium-dose xylitol to a regular and HFD in experimental mice reduced the abundance of fecal Bacteroidetes phylum and the genus Barnesiella, whereas the abundance of Firmicutes phylum and the genus Prevotella was increased in mice fed an HFD with medium-dose dietary xylitol. Body composition, hepatic and serum lipid parameters, oral glucose tolerance, and luminal metabolites were unaffected by xylitol consumption. In mice, 40 and 194 mg/kg body weight/day xylitol in the diet induced gradual changes in gut microbiota but not in lipid metabolism

Early Postnatal Exposure to a Low Dose of Decabromodiphenyl Ether Affects Expression of Androgen and Thyroid Hormone Receptor-Alpha and Its Splicing Variants in Mouse Sertoli Cells

<div><p>Decabromodiphenyl ether (decaBDE) adversely affects reproduction and development. Our previous study showed that postnatal exposure to a low dose of decaBDE (0.025 mg/kg body weight/day) by subcutaneous injection on postnatal days (PNDs) 1 through 5 leads to reductions in testicular size and number of Sertoli cells and sperm, while higher dose of decaBDE (2.5 mg/kg body weight/day) had no significant differences about these. In the present study, we examined the molecular mechanism of these effects on mouse testes following postnatal exposure to a low decaBDE dose. We hypothesized that postnatal exposure to decaBDE may alter levels of serum thyroid hormones (THs) and testosterone, or the level of TH receptor alpha (<i>Thra</i>) transcripts and its splicing variants and androgen receptor (<i>Ar</i>) in Sertoli cells, adversely affecting spermatogenesis. To test this hypothesis, we examined serum TH and testosterone levels and the levels of transcripts of the <i>Ar, Thra</i> and its splicing variants, and <i>Thra</i> splicing factors (<i>Hnrnpa1</i>, <i>Srsf1</i>, and <i>Hnrnph1</i>) with qPCR in isolated mouse Sertoli cells exposed postnatally to decaBDE (0.025, 0.25, and 2.5 mg/kg). Levels of serum testosterone and transcripts encoding <i>Ar</i>, <i>Thra</i>, and its variant, <i>Thra1,</i> declined significantly in Sertoli cells of mice exposed to 0.025 mg decaBDE/kg. No significant differences in serum TH level or <i>Thra2, Hnrnph1</i>, or <i>Srsf1</i> transcript levels were observed between control and decaBDE-exposed mice. However, the <i>Thra1</i>:<i>Thra2</i> and <i>Hnrnpa1</i>:<i>Srsf1</i> ratios were altered in Sertoli cells of mice exposed to 0.025 mg decaBDE/kg but not in cells exposed to 0.25 or 2.5 mg decaBDE/kg. These results indicate that postnatal exposure to a low dose of decaBDE on PNDs 1 through 5 lowers the testosterone level and the levels of <i>Ar</i> and <i>Thra</i> transcripts in Sertoli cells, accompanied by an imbalance in the ratios of <i>Thra</i> splicing variants, resulting in smaller testicular size and impaired spermatogenesis.</p></div

Levels of <i>Thra</i> and <i>Ar</i> transcripts in isolated Sertoli cells.

<p>Levels of transcripts of <i>Thra</i> (A), <i>Thra1</i> (B), <i>Thra2</i> (C), and <i>Ar</i> (D) were measured using qPCR in control and decaBDE-exposed isolated Sertoli cells cultured for 1 week. Transcript expression was normalized to the level of <i>Actb</i> transcript expression and is shown as the ratio relative to <i>Actb</i> compared with the control (set as a value of 1.0). Each value is the mean ± SD of 6-9 samples per group. *<i>P</i><0.05 compared with the control.</p

Possible mechanism following early postnatal exposure to a low dose of decaBDE (0.025 mg/kg) in mouse testis.

<p>Early postnatal exposure to decaBDE from PND 1 to 5 causes to reduce serum testosterone level and <i>Ar</i> transcript levels in Sertoli cells, resulting in smaller testes size, reduced sperm count and a lower number of Sertoli cells, as well as decreased transcript levels of <i>Thra</i> and its splicing variant, <i>Thra1,</i> and an imbalance in the expression ratios of <i>Thra1</i>:<i>Thra2</i> and <i>Hnrnpa1</i>:<i>Srsf1</i> (gray box). It remains unknown if these latter changes are related to smaller testes size, reduced sperm count and lower number of Sertoli cells (dotted line).</p

Serum testosterone levels in control and decaBDE-exposed mice.

<p>Testosterone levels in the serum of control and decaBDE-exposed mice were measured by ELISA. Each value is the mean ± SD of 6 samples per group. *<i>P</i><0.05 compared with the control.</p