Effects of Tyrosine and Tryptophan Supplements on the Vital Indicators in Mice Differently Prone to Diet-Induced Obesity

Excessive Tryptophan and Phenylalanine Induced Pancreatic Injury and Glycometabolism Disorder in Grower-finisher Pigs

BACKGROUND

The increase in circulating insulin levels is associated with the onset of type 2 diabetes (T2D), and the levels of branched-chain amino acids and aromatic amino acids (AAAs) are altered in T2D, but whether AAAs play a role in insulin secretion and signaling remains unclear.

OBJECTIVES

This study aimed to investigate the effects of different AAAs on pancreatic function and on the use of insulin in finishing pigs.

METHODS

A total of 18 healthy finishing pigs (Large White) with average body weight of 100 ± 1.15 kg were randomly allocated to 3 dietary treatments: Con, a normal diet supplemented with 0.68% alanine; Phe, a normal diet supplemented with 1.26% phenylalanine; and Trp, a normal diet supplemented with 0.78% tryptophan. The 3 diets were isonitrogenous. There were 6 replicates in each group.

RESULTS

Herein, we investigated the effects of tryptophan and phenylalanine on pancreatic function and the use of insulin in finishing pigs and found that the addition of tryptophan and phenylalanine aggravated pancreatic fat deposition, increased the relative content of saturated fatty acids, especially palmitate (C16:0) and stearate (C18:0), and the resulting lipid toxicity disrupted pancreatic secretory function. We also found that tryptophan and phenylalanine inhibited the growth and secretion of β-cells, downregulated the gene expression of the PI3K/Akt pathway in the pancreas and liver, and reduced glucose utilization in the liver.

CONCLUSIONS

Using fattening pigs as a model, multiorgan combined analysis of the insulin-secreting organ pancreas and the main insulin-acting organ liver, excessive intake of tryptophan and phenylalanine will aggravate pancreatic damage leading to glucose metabolism disorders, providing new evidence for the occurrence and development of T2D.

Dysfunction of neurotransmitter metabolism is associated with the severity of depression in first-diagnosed, drug-naïve depressed patients

BACKGROUND & AIMS

Biochemical changes of neurotransmitters underlying major depressive disorder (MDD) are unknown. This study preliminarily explored the association between neurotransmitters with MDD and the possibility of objective laboratory prediction of neurotransmitter involvement in MDD.

METHODS

A total of 87 first-diagnosed, drug-naïve patients with depression and 50 healthy controls (HCs) were included in the cross-sectional study. The levels and turnovers of neurotransmitters (glutamine (GLN), glutamic acid (GLU), γ-2Aminobutiric acid (GABA), kainate (KA), vanillylmandelic acid (VMA), 3-methoxy 4-hydroxyphenyl ethylene glycol (MHPG), noradrenaline (NE), homovanillic acid (HVA), dihydroxy-phenyl acetic acid (DOPAC), dopamine (DA), tryptophane (TRP), kynurenine (KYN), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA)) were determined and the confounding factors were adjusted. Then a correlation and a predictive analysis towards neurotransmitters for MDD were performed.

RESULTS

After adjusting confounding factors, GLU (OR = 1.159), (GLU+ GABA)/GLN (OR = 1.217), DOPAC (OR = 1.106), DOPAC/DA (OR = 1.089) and (DOPAC+ HVA)/DA (OR = 1.026) enacted as risk factors of MDD, while KYN (OR = 0.992) was a protective factor. GABAergic and TRPergic pathways were associated with severity of depressive and anxiety symptoms in patients with depression. The predictive model for MDD (AUC = 0.775, 95%CI 0.683-0.860) consisted of KYN (OR = 0.990) and (GLU + GABA)/GLN (OR = 4.101).

CONCLUSIONS

First-diagnosed, drug-naïve depression patients showed abnormal neurotransmitter composition. GLU, (GLU + GABA)/GLN, DOPAC, DOPAC/DA and (DOPAC + HVA)/DA were risk factors of MDD, while KYN was a protective factor. GABAergic and TRPergic pathways were correlated with MDD clinical characteristics. KYN and (GLU + GABA)/GLN may have a predictive value for MDD.

Efficacy of Triphala extracts on the changes of obese fecal microbiome and metabolome in the human gut model

Triphala is a mixture of tree fruits obtained from Terminalia chebula, Terminalia bellerica, and Phyllanthus emblica. It is one of the Ayurveda medicinal recipes used to treat health diseases such as obesity. The chemical composition analysis of Triphala extracts obtained from an equal portion of three fruits was performed. The contents of total phenolic compounds (62.87 ± 0.21 mg gallic acid equivalent/mL), total flavonoids (0.24 ± 0.01 mg catechin equivalent/mL), hydrolyzable tannins (177.27 ± 10.09 mg gallotannin equivalent/mL), and condensed tannins (0.62 ± 0.11 mg catechin equivalent/mL) were observed in Triphala extracts. The 1 mg/mL of Triphala extracts was applied to batch culture fermentation which contained the feces from voluntarily obese female adults (body mass index of 35.0-40.0 kg/m²) for 24 h. The extraction of DNA and metabolites was each conducted on the samples obtained from batch culture fermentation within and without Triphala extracts treatment. The 16S rRNA gene sequencing and untargeted metabolomic analysis were carried out. There was no statistically significant difference between Triphala extracts and control treatments on the changes in microbial profiles (p-value <0.05). While the metabolomic analysis showed statistically significant differences of 305 up-regulated and 23 down-regulated metabolites in the treatment of Triphala extracts when compared with the control (p-value <0.05 and fold-change ≥2) belonging to 60 pathways. The pathway analysis revealed that Triphala extracts play an important role in the activation of phenylalanine, tyrosine and tryptophan biosynthesis. In this study, phenylalanine and tyrosine were identified metabolites which involve in the regulation of energy metabolism. The treatment of Triphala extracts possesses the induction of phenylalanine, tyrosine and tryptophan biosynthesis in fecal batch culture fermentation of obese adults and therefore it can be suggested as a probable herbal medicinal recipe for obesity treatment.

NMR-Based Metabolomics Approach to Investigate the Effects of Fruits of Acanthopanax sessiliflorus in a High-Fat Diet Induced Mouse Model

The prevalence of obesity is rapidly increasing and is recognized as a serious health problem. To investigate metabolic changes in an obese model after administration of Acanthopanax sessiliflorus, mice were divided into four groups: normal diet, high-fat diet (HFD), HFD with treatment fenofibrate, and A. sessiliflorus fruit extract. The liver tissue of mice was analyzed using nuclear magnetic resonance (NMR) spectrometry-based metabolomics. In multivariate statistical analyses, the HFD group was discriminated from the normal diet group, and the group fed A. sessiliflorus fruit was discriminated from the HFD group. In biomarker analysis between the HFD group and the group fed A. sessiliflorus fruit, alanine, inosine, formate, pyroglutamate, taurine, and tyrosine, with AUC values of 0.7 or more, were found. The levels of these metabolites were distinguished from the HFD mouse model. Changes in these metabolites were confirmed to act on metabolic pathways related to antioxidant activity.