Comparison of Urinary Excretion of Taurine Between Elderly with Dementia and Normal Elderly

Synthesis of versatile neuromodulatory molecules by a gut microbial glutamate decarboxylase

Dysbiosis of the microbiome correlates with many neurological disorders, yet very little is known about the chemistry that controls the production of neuromodulatory molecules by gut microbes. Here, we found that an enzyme glutamate decarboxylase (BfGAD) of a gut microbe Bacteroides fragilis forms multiple neuromodulatory molecules such as γ-aminobutyric acid (GABA), hypotaurine, taurine, homotaurine, and β-alanine. We evolved BfGAD and doubled its taurine productivity. Additionally, we increased its specificity towards the substrate L-glutamate. Here, we provide a chemical strategy via which the BfGAD activity could be fine-tuned. In future, this strategy could be used to modulate the production of neuromodulatory molecules by gut microbes.

Urinary and faecal metabolic characteristics in APP/PS1 transgenic mouse model of Alzheimer's disease with and without cognitive decline

Alzheimer's disease (AD) has been considered to be a systematic metabolic disorder, but little information is available about metabolic changes in the urine and feces. In this study, we investigated urinary and faecal metabolic profiles in amyloid precursor protein/presenilin 1 (APP/PS1) mice at 3 and 9 months of age (3 M and 9 M) and age-matched wild-type (WT) mice by using ¹H NMR-based metabolomics, and aimed to explore changes in metabolic pathways during amyloid pathology progression and identify potential metabolite biomarkers at earlier stage of AD. The results show that learning and memory abilities were impaired in APP/PS1 mice relative to WT mice at 9 M, but not at 3 M. However, metabolomics analysis demonstrates that AD disrupted metabolic phenotypes in the urine and feces of APP/PS1 mice at both 3 M and 9 M, including amino acid metabolism, microbial metabolism and energy metabolism. In addition, several potential metabolite biomarkers were identified for discriminating AD and WT mice prior to cognitive decline with the AUC values from 0.755 to 0.971, such as taurine, hippurate, urea and methylamine in the urine as well as alanine, leucine and valine in the feces. Therefore, our results not only confirmed AD as a metabolic disorder, but also contributed to the identification of potential biomarkers at earlier stage of AD.

Urine metabolic profiling of dementia rats with vital energy deficiency using ultra-high-performance liquid chromatography coupled with an orbitrap mass spectrometer

Dementia is a chronic and multifactor-induced neurodegenerative disorder that occurs frequently in the elderly with weak constitution and insufficient vital energy. However, the relationship between vital energy deficiency and the occurrence and development of dementia is still unclear. In this study, a rat model of dementia with vital energy deficiency was established through intraperitoneal injection with d-galactose and AlCl₃ and combined with exhaustive swimming. Changes in the dementia with vital energy deficiency rat model were assessed by examining behaviors, hippocampal histopathological and biochemical parameters, and serum biochemical parameters. Urine metabolomics based on ultra-high-performance liquid chromatography coupled with an orbitrap mass spectrometer was also used to discover endogenous metabolic profile and disease-related biomarkers and investigate the potential mechanism of dementia with vital energy deficiency. Among the 31 potential biomarkers that were identified, nine involved metabolic pathways. The four main types were phenylalanine, tyrosine and tryptophan metabolism, taurine and hypotaurine metabolism, and citrate cycle and pyrimidine metabolism. The pathogenesis of dementia with vital energy deficiency is mainly neurotoxin accumulation and body aging that leads to oxidative stress injury and loss of neuronal protective substances. Vital energy deficiency inhibits the body's energy metabolism and eventually leads to aggravate the dementia.

Effects of Dietary Taurine Supplementation on Blood and Urine Taurine Concentrations in the Elderly Women with Dementia

The purpose of this research is to investigate the effects of dietary taurine supplementation on blood and urine taurine concentrations of the elderly women with dementia. Subjects were 31 female elderly with dementia hospitalized in a geriatric hospital. They were divided randomly into control group and dietary taurine supplemented group. Basically, same meals were served to both groups. Scorched rice water without taurine were served to control group. Scorched rice water containing 3 g of taurine were reserved to taurine group with lunch similarly. Food ingredients containing high concentration of taurine were eliminated from the meal menu. Blood and urine samples were obtained from each subject at the beginning of study, after 2 week and 4 weeks in the morning fasting state. Taurine concentrations in serum and urine were measured as taurine-fluorescamine derivatives using high performance liquid chromatography (HPLC). Data were analyzed using SPSS 20.0. The average taurine concentrations in serum and urine of subjects were 89.2 ± 9.5 μM and 876.7 ± 97.1 μM at the beginning. After 4 weeks, the taurine concentrations in serum and urine of dietary taurine supplemented group were 218.0 ± 15.6 μM and 6502.6 ± 380.6 μM, which were significantly higher compared to control group. Dietary taurine supplemented group showed positive changes in the score on language and execute performance. So taurine supplementation can provide beneficial effects to the elderly and the elderly with dementia.