Oligofructose improves small intestinal lipid-sensing mechanisms via alterations to the small intestinal microbiota

BACKGROUND

Upper small intestinal dietary lipids activate a gut-brain axis regulating energy homeostasis. The prebiotic, oligofructose (OFS) improves body weight and adiposity during metabolic dysregulation but the exact mechanisms remain unknown. This study examines whether alterations to the small intestinal microbiota following OFS treatment improve small intestinal lipid-sensing to regulate food intake in high fat (HF)-fed rats.

RESULTS

In rats fed a HF diet for 4 weeks, OFS supplementation decreased food intake and meal size within 2 days, and reduced body weight and adiposity after 6 weeks. Acute (3 day) OFS treatment restored small intestinal lipid-induced satiation during HF-feeding, and was associated with increased small intestinal CD36 expression, portal GLP-1 levels and hindbrain neuronal activation following a small intestinal lipid infusion. Transplant of the small intestinal microbiota from acute OFS treated donors into HF-fed rats also restored lipid-sensing mechanisms to lower food intake. 16S rRNA gene sequencing revealed that both long and short-term OFS altered the small intestinal microbiota, increasing Bifidobacterium relative abundance. Small intestinal administration of Bifidobacterium pseudolongum to HF-fed rats improved small intestinal lipid-sensing to decrease food intake.

CONCLUSION

OFS supplementation rapidly modulates the small intestinal gut microbiota, which mediates improvements in small intestinal lipid sensing mechanisms that control food intake to improve energy homeostasis. Video Abstract.

The effects of 6-month hydrogen-rich water intake on molecular and phenotypic biomarkers of aging in older adults aged 70 years and over: A randomized controlled pilot trial

In this randomized controlled pilot trial, we investigated the effects of a 6-month intake of hydrogen-rich water (HRW) on several molecular and phenotypic biomarkers of aging in older adults aged 70 years and over. Forty older adults (20 women) were randomly allocated in a parallel-group design to receive 0.5 L per day of HRW (15 ppm of hydrogen) or control drink (0 ppm of hydrogen) during a 6-month intervention period. The biomarkers assessed at baseline and 6-month follow up were molecular markers in the blood (DNA and chromosomes, nutrient sensing, protein, and lipid metabolism, oxidative stress and mitochondria, cell senescence, inflammation), brain metabolism, cognitive functioning, physical function and body composition, resting blood pressure, facial skin features, sleep outcomes, and health-related quality of life. The mean age, weight, and height of study participants were 76.0 ± 5.6 years, 78.2 ± 16.1 kg, height 167.5 ± 11.5 cm, respectively. A significant treatment vs. time interaction was found for telomere length (P = 0.049), with the length increased after HRW intervention (from 0.99 ± 0.15 at baseline to 1.02 ± 0.26 at follow up) and decreased after drinking control water (from 0.92 ± 0.27 to 0.79 ± 0.15). A marker of DNA methylation (Tet methylcytosine dioxygenase 2, TET2) expression at 6-month follow-up increased in both groups, yet the degree of elevation was significantly higher in HRW (from 0.81 ± 0.52 at baseline to 1.62 ± 0.66 at follow up) comparing to the control water (from 1.13 ± 0.82 to 1.76 ± 0.87) (P = 0.040). A strong trend for treatment vs. time interaction was found for a degree of DNA methylation (P = 0.166), with the methylation increased in the HRW group (from 120.6 ± 39.8 ng at baseline to 126.6 ± 33.8 ng at follow up) and decreased after taking control water (from 133.6 ± 52.9 ng to 121.2 ± 38.4 ng). HRW was superior to control water to increase brain choline and NAA levels in the left frontal grey matter, brain creatine at the right parietal white matter, and brain NAA at the right parietal mesial grey matter (P < 0.05). No significant differences were found between interventions for other outcomes (P > 0.05), except for a significantly improved chair stand performance after HRW intervention compared to the control water (P = 0.01). Owing to pleiotropic mechanisms of hydrogen action, this simple biomedical gas could be recognized as a possible anti-aging agent that tackles several hallmarks of aging, including loss of function and telomere length shortening. The study was registered at ClinicalTrials.gov (NCT04430803).

Lysosome trafficking and signaling in health and neurodegenerative diseases

Lysosomes, single-membrane organelles defined by a uniquely strong acidic lumenal pH and high content of acid hydrolases, are the shared degradative compartments of the endocytic and autophagic pathways. These pathways, and especially lysosomes, are points of particular vulnerability in many neurodegenerative diseases. Beyond the role of lysosomes in substrate degradation, new findings have ascribed to lysosomes the leading role in sensing and responding to cellular nutrients, growth factors and cellular stress. This review aims to integrate recent concepts of basic lysosome biology and pathobiology as a basis for understanding neurodegenerative disease pathogenesis. Here, we discuss the newly recognized signaling functions of lysosomes and specific aspects of lysosome biology in neurons while re-visiting the classical defining criteria for lysosomes and the importance of preserving strict definitions. Our discussion emphasizes dynein-mediated axonal transport of maturing degradative organelles, with further consideration of their roles in synaptic function. We finally examine how distinctive underlying disturbances of lysosomes in various neurodegenerative diseases result in unique patterns of auto/endolysosomal mistrafficking. The rapidly emerging understanding of lysosomal trafficking and disruptions in lysosome signaling is providing valuable clues to new targets for disease-modifying therapies.