An Association between Decreased Small Intestinal RNA Modification and Disturbed Glucagon-like Peptide-1 Secretion under High-Fat Diet Stress.

Unhealthy diets rich in fats and/or sugar are considered as the major external cause of the obesity epidemic, which is often accompanied by a significant decrease in gut hormone glucagon-like peptide-1 (GLP1) levels. Numerous studies have demonstrated notable contributions of the gut microbiota in this process. Nevertheless, the underlying mechanism still needs further investigation. The role of epigenetic modifications in gene expression and metabolism has been well demonstrated, with m6A methylation on RNAs being the most prevalent modification throughout their metabolism. In the present study, we found that the expressions of small intestinal Gcg and Pc3, two key genes regulating GLP1 expression, were significantly downregulated in obese mice, associated with reduced GLP1 level. Immunohistochemistry analysis indicated that a high-fat diet slightly increased the density of enteroendocrine L cells in the small intestine, implying that decreased GLP1 levels were not caused by the changes in L cell intensity. Instead, the small intestinal m6A level as well as the expression of known "writers", mettl3/14 and wtap, were found to be positively correlated with the expression of Gcg and Pc3. Fecal microbiota transplantation with feces from normal and obese mice daily to antibiotic-treated mice revealed that dysbiosis in diet-induced obesity was sufficient to reduce serum GLP1, small intestinal m6A level, and intestinal expressions of Gcg, Pc3, and writer genes (mettl3/14, wtap). However, as the most direct and universal methyl donor, the production of fecal S-adenosylmethionine was neither affected by the different dietary patterns nor their shaped microbiota. These results suggested that microbial modulation of the epitranscriptome may be involved in regulating GLP1 expression, and highlighted epitranscriptomic modifications as an additional level of interaction between diet and individual health.

Obesity is negatively associated with dental caries among children and adolescents in Huizhou: a cross-sectional study.

BACKGROUND: Obesity and dental caries among children and adolescents are growing worldwide public health problems. They share some common and modifiable influences. The objective of this study was to evaluate the prevalence of obesity and dental caries among children and adolescents in Huizhou and explore the association between Body Mass Index (BMI) category and dental caries. METHODS: This cross-sectional study enrolled 105,181 students (55,500 males and 49,681 females) from 87 schools in Huizhou. Height and weight were measured, and BMI was calculated. Based on Chinese BMI standards, students were classified into underweight, normal weight, overweight, and obesity groups. Dental caries was diagnosed according to criteria recommended by World Health Organization (WHO). We used the Chi-square test to compare proportions of groups and performed Association Rules Mining to identify patterns and combinations of BMI categories and dental caries. Finally, a multilevel logistic regression model was applied to analyze the association between BMI category and dental caries when confounders were considered. RESULTS: The prevalence of underweight, overweight, and obesity among children and adolescents was 7.56%, 8.85%, and 2.95%, respectively. The overall prevalence of dental caries was 58.10%, with a lower prevalence among boys than girls. Students from primary schools and remote towns more easily suffer from dental caries. Caries prevalence of students belonged to underweight, normal, overweight, and obesity was 65.6%, 58.8%, 49.6%, and 46.1% individually. With increasing BMI levels, the prevalence of dental caries decreased. Further, this trend still exists in each subgroup of gender, educational stage, school type, and area. Association rules indicate underweight has a positive effect on the occurrence of dental caries, while overweight or obesity has a negative impact on the occurrence of dental caries. The three-level logistic regression model results show that BMI category is inversely associated with dental caries after adjusting confounders. CONCLUSION: Obesity is negatively associated with dental caries among children and adolescents in Huizhou. Further research is required to investigate how dietary habits, oral hygiene habits, and parental socioeconomic status mediate the association between BMI and dental caries.