Association of Gut Microbiota-Related Metabolites and Type 2 Diabetes in Two Puerto Rican Cohorts.

(1) Aims: Gut microbiota metabolites may play integral roles in human metabolism and disease progression. However, evidence for associations between metabolites and cardiometabolic risk factors is sparse, especially in high-risk Hispanic populations. We aimed to evaluate the cross-sectional and longitudinal relationships between gut microbiota related metabolites and measures of glycemia, dyslipidemia, adiposity, and incident type 2 diabetes in two Hispanic observational cohorts. (2) Methods: We included data from 670 participants of the Boston Puerto Rican Health Study (BPRHS) and 999 participants of the San Juan Overweight Adult Longitudinal Study (SOALS). Questionnaires and clinical examinations were conducted over 3 years of follow-up for SOALS and 6 years of follow-up for BPRHS. Plasma metabolites, including L-carnitine, betaine, choline, and trimethylamine N-oxide (TMAO), were measured at baseline in both studies. We used multivariable linear models to evaluate the associations between metabolites and cardiometabolic risk factors and multivariable logistic and Poisson regressions to assess associations with prevalent and incident type 2 diabetes, adjusted for potential confounding factors. Cohort-specific analyses were combined using a fixed-effects meta-analysis. (3) Results: Higher plasma betaine was prospectively associated with lower fasting glucose [-0.97 mg/dL (95% CI: -1.59, -0.34), p = 0.002], lower HbA1c [-0.02% (95% CI: -0.04, -0.01), p = 0.01], lower HOMA-IR [-0.14 (95% CI: -0.23, -0.05), p = 0.003], and lower fasting insulin [-0.27 mcU/mL (95% CI: -0.51, -0.03), p = 0.02]. Betaine was also associated with a 22% lower incidence of type 2 diabetes (IRR: 0.78, 95% CI: 0.65, 0.95). L-carnitine was associated with lower fasting glucose [-0.68 mg/dL (95% CI: -1.29, -0.07), p = 0.03] and lower HbA1c at follow-up [-0.03% (95% CI: -0.05, -0.01), p < 0.001], while TMAO was associated with higher fasting glucose [0.83 mg/dL (95% CI: 0.22, 1.44), p = 0.01] and higher triglycerides [3.52 mg/dL (95% CI: 1.83, 5.20), p < 0.0001]. Neither choline nor TMAO were associated with incident type 2 diabetes. (4) Conclusions: Higher plasma betaine showed consistent associations with a lower risk of glycemia, insulinemia, and type 2 diabetes. However, TMAO, a metabolite of betaine, was associated with higher glucose and lipid concentrations. These observations demonstrate the importance of gut microbiota metabolites for human cardiometabolic health.

IFN-ß regulates Th17 differentiation partly through the inhibition of osteopontin in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) and the corresponding animal model, experimental autoimmune encephalomyelitis (EAE), are chronic neuroinflammatory autoimmune diseases. Increased activation of CD4+T cells, especially the Th1 and Th17 subsets, is thought to play a causal role in this disease. IFN-ß is widely used in the treatment of MS and is found to decrease IL-17 and OPN production in MS patients and EAE mice. However, a definitive molecular mechanism has not yet been fully elucidated. In this study, we investigated the immunomodulatory effect of IFN-ß on the EAE model. We observed disease progression and determined the percentage of Th1/Th17 cells in the peripheral immune organs, brain, and spinal cord of mice. Furthermore, the levels of related cytokines and transcription factors were measured in splenocytes, and the effects of IFN-ß on Th17 differentiation were assessed in vitro. Compared to the control group, IFN-ß treatment significantly reduced the incidence of EAE and the associated pathological damage. Th1 and Th17 cells in IFN-ß-treated mice were significantly reduced, and the levels of cytokines, such as IFN-γ, IL-17, and OPN, were significantly decreased in splenocyte supernatants as well as the levels of corresponding transcription factors. IFN-ß inhibited downstream inflammatory cytokines through the inhibition of PI3K/AKT/NF-κB axis and p38, JNK-MAPK, as well as the regulation of mTOR complexes. Moreover, IFN-ß inhibited Th17 differentiation and neutralizing OPN antibodies offset the inhibitory effect of IFN-ß on Th17 cells. Meanwhile, IFN-ß influenced the acetylation of the Il17a and Opn gene promoters. The findings described herein provide novel evidence for the role of IFN-ß in Th17 differentiation partly through the inhibition of OPN.

Dental noise exposed mice display depressive-like phenotypes.

BACKGROUND: Studies have indicated that depressive disorders are observed frequently in dentists. It's suggested that dentists encounter numerous sources of stress in their professional career. We noticed that the noises in dental environments are very unpleasant. The animal modeling studies suggested that stressful noise could produce depressive-like phenotypes in rodent animals. We hypothesize that the dental noise may be one of the primary stressors causing depressive disorders in dentists. RESULTS: We treated C57BL/6 mice with programmatically played wide-spectrum dental noise for 8 h/day at 75 ± 10 dB SPL level for 30 days, and then tested the behaviors. After exposure to dental noise, animals displayed the depressive-like phenotypes, accompanied by inhibition of neurogenesis in hippocampus. These deficits were ameliorated by orally administered with antidepressant fluoxetine. CONCLUSIONS: Our results suggested that dental noise could be one of the primary stressors for the pathogenesis of depressive disorders and the dental noise mouse model could be used in further depression studies.