Levels Of Aromatic Amino Acids Research Articles

Frailty and sarcopenia metabolomic signatures in kidney transplant candidates: the frailmar study

Abstract Sarcopenia and frailty are often overlooked in assessing kidney transplant (KT) candidates with chronic kidney disease (CKD), potentially leading to poor post-transplant outcomes. This study aimed to identify metabolites associated with frailty and sarcopenia in KT-candidates from the FRAILMAR study. Between June 2016 and June 2020, we evaluated frailty and sarcopenia in 173 KT-candidates using the Physical Frailty Phenotype and EGWSOP-2 criteria, respectively. Seventy-five metabolic markers from targeted pathways, previously linked to CKD, sarcopenia, or frailty, were measured in serum samples. These markers were analyzed using adjusted and weighted generalized linear models. Metabolomic data were integrated with multi-modal data, such as comorbidities, using a factor-based integration algorithm to identify metabolic phenotypes. Increased metabolites related to energy metabolism and essential amino acids were associated with frailty, mainly Krebs cycle intermediates. Sarcopenic KT-candidates showed lower levels of aromatic amino acids, lower protein/muscle metabolism, energy metabolism, and neurotransmission compared to non-sarcopenic patients. Unsupervised multi-modal integration revealed a high-risk metabolic phenotype characterized by the presence of sarcopenia, diabetes mellitus, and low body mass index, with alterations in branched-chain amino acids and high activity of lactate dehydrogenase enzyme. Frailty and sarcopenia are common among KT-candidates, and their metabolic status reveal notable disruptions in energy and amino acid metabolism. These findings highlight the value of a detailed metabolic assessment to more accurately evaluate patient health status prior to transplantation.

Metabolomic characterization of unintentional weight loss among community-dwelling older Black and White men and women.

This study aims to understand the metabolic mechanisms of unintentional weight loss in older adults. We investigated plasma metabolite associations of subsequent weight change over 2 years in 1536 previously weight stable participants (mean age 74.6 years, 50% women, 35% Black) from the Health, Aging and Body Composition (Health ABC) Study. Multinomial logistic regressions were used to examine associations of the 442 metabolites with weight loss with/without an intention and weight gain >3% annually relative to weight stability. The metabolite associations of unintentional weight loss differed from those of intentional weight loss and weight gain. Lower levels of aromatic amino acids, phospholipids, long-chain poly-unsaturated triglycerides, and higher levels of amino acid derivatives, poly-unsaturated fatty acids, and carbohydrates were associated with higher odds of unintentional weight loss after adjusting for age, sex, race, and BMI categories. Prevalent diseases attenuated four and lower mid-thigh muscle mass and poorer appetite each attenuated 2 of 77 identified metabolite associations by >20%, respectively. Other factors (e.g., energy expenditure, diet, and medication) attenuated all associations by <20%. While 16 metabolite associations were attenuated by 20%-48% when adjusting for all these risk factors, 47 metabolite associations remained significant. Altered amino acid metabolism, impaired mitochondrial fatty acid oxidation, and inflammaging implicated by identified metabolites appear to precede unintentional weight loss in Health ABC older adults. Furthermore, these pathways seem to be associated with prevalent diseases especially diabetes, lower muscle mass, and poorer appetite.

In vitro antioxidants and anti-inflammatory potentials of high protein-fibre cookies produced from whole wheat, sweet potato, rice bran and peanut composite flour blends

The growing demand for low-cost and functional snacks in many developing nations called for interest in the use of locally grown crops as substitutes for costly imported wheat flour. The amino acid composition, antioxidant and anti-inflammatory properties of the cookies from whole wheat, sweet potato, rice bran and peanut (56.25:18.75:5:20; 37.50:37.50:5:20; 18.75:56.25:5:20% as WPRG 1, WPRG 2, WPRG 3) composite flour blends, respectively, were obtained in this study. The 100% whole wheat and 100% refined flours served as control 1 and 2, respectively. The level of hydrophobic and aromatic amino acids was significantly (p < 0.05) high in WPRG 2 (~ 30 and ~ 10%), respectively when compared to others. However, the branched chain amino acids and Fischer ratio was significantly (p < 0.05) high in WPRG 1 (11.40% and 1.29), respectively, which could have contributed to their improved bioactivities. Notably, the composite cookie samples WPRG 1, 2 and 3 had higher hydroxyl (73.86 − 84.16%), DPPH (76.52 − 84.60%) radical scavenging as well as ferric reducing antioxidant (0.64–0.87 mmolFe2+/mg) properties than the control samples WWF and CWF, respectively. On the contrary, the metal chelating activities of the cookies WPRG 1–3 were not significantly (p > 0.05) different from control samples WWF and CWF. The improved amino acid profile and enhanced antioxidant properties of the composite cookies might have effectively influenced their anti-inflammatory properties (IC50; < 26 μg/ml) when compared to the control samples (IC50; ~ 40 μg/ml), respectively. Hence, the cookies that comprised of antioxidants and anti-inflammatory potentials needed in human health, were acceptable by the consumers.Graphical

Effects of postbiotics on chronic diarrhea in young adults: a randomized, double-blind, placebo-controlled crossover trial assessing clinical symptoms, gut microbiota, and metabolite profiles.

Chronic diarrhea has a considerable impact on quality of life. This randomized, double-blind, placebo-controlled crossover intervention trial was conducted with 69 participants (36 in Group A, 33 in Group B), aiming to investigate the potential of postbiotics in alleviating diarrhea-associated symptoms. Participants received postbiotic Probio-Eco® and placebo for 21 days each in alternating order, with a 14-day washout period between interventions. The results showed that postbiotic intake resulted in significant improvements in Bristol stool scale score, defecation frequency, urgency, and anxiety. Moreover, the postbiotic intervention increased beneficial intestinal bacteria, including Dysosmobacter welbionis and Faecalibacterium prausnitzii, while reducing potential pathogens like Megamonas funiformis. The levels of gut Microviridae notably increased. Non-targeted metabolomics analysis revealed postbiotic-driven enrichment of beneficial metabolites, including α-linolenic acid and p-methoxycinnamic acid, and reduction of diarrhea-associated metabolites, including theophylline, piperine, capsaicin, and phenylalanine. Targeted metabolomics confirmed a significant increase in fecal butyric acid after postbiotic intervention. The levels of aromatic amino acids, phenylalanine and tryptophan, and their related metabolites, 5-hydroxytryptophan and kynurenine, decreased after the postbiotic intervention, suggesting diarrhea alleviation was through modulating the tryptophan-5-hydroxytryptamine and tryptophan-kynurenine pathways. Additionally, chenodeoxycholic acid, a diarrhea-linked primary bile acid, decreased substantially. In conclusion, postbiotics have shown promise in relieving chronic diarrhea.

Fecal microbiota transplantation accelerates restoration of florfenicol-disturbed intestinal microbiota in a fish model

Antibiotic-induced dysbiosis in the fish gut causes significant adverse effects. We use fecal microbiota transplantation (FMT) to accelerate the restoration of florfenicol-perturbed intestinal microbiota in koi carp, identifying key bacterial populations and metabolites involved in the recovery process through microbiome and metabolome analyses. We demonstrate that florfenicol disrupts intestinal microbiota, reducing beneficial genera such as Lactobacillus, Bifidobacterium, Bacteroides, Romboutsia, and Faecalibacterium, and causing mucosal injuries. Key metabolites, including aromatic amino acids and glutathione-related compounds, are diminished. We show that FMT effectively restores microbial populations, repairs intestinal damage, and normalizes critical metabolites, while natural recovery is less effective. Spearman correlation analyses reveal strong associations between the identified bacterial genera and the levels of aromatic amino acids and glutathione-related metabolites. This study underscores the potential of FMT to counteract antibiotic-induced dysbiosis and maintain fish intestinal health. The restored microbiota and normalized metabolites provide a basis for developing personalized probiotic therapies for fish.

LC-MS/MS-based bioanalysis of branched-chain and aromatic amino acids in human serum.

Aim: Branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) were suggested as potential biomarkers in liver disease. This study aimed to develop and validate a simple and rapid LC-MS/MS method to simultaneously measure serum BCAAs and AAAs levels in patients with liver injury, and further establish reference intervals of Chinese healthy adult populations.Patients & methods: Samples were prepared by a one-step protein precipitation and analysis time was 4min per run.Results: The validation results showed good linearity (r2>0.9969), satisfactory accuracy (94.44%-107.75%) and precision (0.10%-5.90%).Conclusion: This method proved to be suitable for high-throughput routine clinical use and could be a valuable adjunct diagnosis tool for liver injury and other clinical applications.

Properties and Functional Analysis of Two Chorismate Mutases from Maritime Pine.

Through the shikimate pathway, a massive metabolic flux connects the central carbon metabolism with the synthesis of chorismate, the common precursor of the aromatic amino acids phenylalanine, tyrosine, and tryptophan, as well as other compounds, including salicylate or folate. The alternative metabolic channeling of chorismate involves a key branch-point, finely regulated by aromatic amino acid levels. Chorismate mutase catalyzes the conversion of chorismate to prephenate, a precursor of phenylalanine and tyrosine and thus a vast repertoire of fundamental derived compounds, such as flavonoids or lignin. The regulation of this enzyme has been addressed in several plant species, but no study has included conifers or other gymnosperms, despite the importance of the phenolic metabolism for these plants in processes such as lignification and wood formation. Here, we show that maritime pine (Pinus pinaster Aiton) has two genes that encode for chorismate mutase, PpCM1 and PpCM2. Our investigations reveal that these genes encode plastidial isoenzymes displaying activities enhanced by tryptophan and repressed by phenylalanine and tyrosine. Using phylogenetic studies, we have provided new insights into the possible evolutionary origin of the cytosolic chorismate mutases in angiosperms involved in the synthesis of phenylalanine outside the plastid. Studies based on different platforms of gene expression and co-expression analysis have allowed us to propose that PpCM2 plays a central role in the phenylalanine synthesis pathway associated with lignification.

Targeted metabolomic profiles of serum amino acids are independently correlated with malnutrition in older adults.

Malnutrition is a common geriatric syndrome that is closely associated with adverse clinical outcomes and poses significant harm to older adults. Early assessment of nutritional status plays a crucial role in preventing and intervening in cases of malnutrition. However, there is currently a lack of measurable methods and biomarkers to evaluate malnutrition in older adults accurately. The aim of this study is to investigate the independent correlation between serum levels of amino acids and malnutrition in older adults, and to identify effective metabolomics biomarkers that can aid in the early detection of geriatric malnutrition. A total of 254 geriatric medical examination participants from Beijing Hospital were included in the study, consisting of 182 individuals with normal nutritional status (Normal group) and 72 patients at risk of malnutrition or already malnourished (MN group). Malnutrition was assessed using the Mini-Nutritional Assessment Short-Form (MNA-SF). Demographic data were collected, and muscle-related and lipid indexes were determined. Serum amino acid concentrations were measured using isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). The correlation between serum amino acid levels and malnutrition was analyzed using non-parametric tests, partial correlation analysis, linear regression, and logistic regression. The geriatric MN group exhibited significantly lower serum aromatic amino acid levels (P < 0.05) compared to the normal group. A positive correlation was observed between serum aromatic amino acid levels and the MNA-SF score (P = 0.002), as well as with known biomarkers of malnutrition such as body mass index (BMI) (P < 0.001) and hemoglobin (HGB) (P = 0.005). Multivariable logistic or linear regression analyses showed that aromatic amino acid levels were negatively correlated with MN and positively correlated with the MNA-SF score, after adjusting for some confounding factors, such as age, gender, BMI, smoking status, history of dyslipidemia, diabetes mellitus and frailty. Stratified analyses revealed that these trends were more pronounced in individuals without a history of frailty compared to those with a history of frailty, and there was an interaction between aromatic amino acid levels and frailty history (P = 0.004). Our study suggests that serum aromatic amino acids are independently associated with malnutrition in older adults. These results have important implications for identifying potential biomarkers to predict geriatric malnutrition or monitor its progression and severity, as malnutrition can result in poor clinical outcomes.

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

BackgroundThe 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. ObjectivesThis study aimed to investigate the effects of different AAAs on pancreatic function and on the use of insulin in finishing pigs. MethodsA 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. ResultsHerein, 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. ConclusionsUsing 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.

Plasma amino acids spectrum and Holter ECG monitoring indexes in coronary artery disease patients with atrial fibrillation

The research was conducted with the aim of establishing a connection between plasma amino acid peculiarities and Holter ECG monitoring indexes in Coronary Artery Disease (CAD) and Atrial Fibrillation (AF) patients. 300 patients were examined divided into 3 groups: I – 149 patients with CAD without arrhythmias, II – 124 patients with CAD and AF paroxysm, and the Control Group (CG) – 27 patients without CAD and arrhythmias. Holter ECG monitoring was performed for the patients with AF within 24 hours after sinus rhythm restoration, and for the patients without AF on the first day of observation. Plasma AA level was detected by the method of ion exchange liquid column chromatography. It was established that there is a significant increase glutamate and Branched-Chain Amino Acids (BCAA) levels in patients of the II group, and significant depletion in glycine levels comparison with the I group patients (p&lt;0.05). In the II group patients, an increase in SupraVentricular (SVE) and Ventricular Extrasystoles (VE) was checked in comparison with the I group patients (p&lt;0.05). Total SVE was significantly correlated with threonine (r=-0.316), serine (r=-0.336), glycine (r=-0.397), isoleucine (r=0.317), BCAA (r=0.356), and glycine+serine sum (r=-0.302), p&lt;0.05. AF paroxysm was significantly correlated with taurine (r=-0.302), serine (r=-0.328), glycine (r=-0.311), glutamine (r=-0.304), and glycine+serine sum (r=-0.379), p&lt;0.05. Total VE was significantly correlated with glycine (r=-0.370) and tyrosine (r=0.325), p&lt;0.05. Changes in ST-segment were significantly correlated with tyrosine (r=0.307), phenylalanine (r=0.318), and Aromatic Amino Acids (AAA) (r=0.379), p&lt;0.05. We concluded that glycine, serine, and BCAA are significantly correlated with cardiac arrhythmias. Changes in ST segment are significantly correlated with AAA levels. Keywords: heart rhythm violations, ischemia, arrhythmia, metabolomics.

Impact of dietary digestible aromatic amino acid levels and stachyose on growth, nutrient utilization, and cecal odorous compounds in broiler chickens

This study evaluated the impact of dietary digestible aromatic amino acid (DAAA) levels and stachyose on growth, nutrient utilization and cecal odorous compounds in broiler chickens. A 3×2 two-factor factorial design: Three dietary DAAA levels (1.40, 1.54, 1.68%) supplemented with either 5 g/kg of stachyose or without any stachyose were used to create 6 experimental diets. Each diet was fed to 6 replicates of 10 birds from d 22 to 42. Findings revealed that broilers receiving a diet with 1.54% DAAA levels supplemented with 5 g/kg stachyose exhibited a significant boost in average daily gain and improved utilization of crude protein, ether extract, tryptophan, and methionine compared to other diet treatments (P < 0.05). As the dietary DAAA levels increased, there was a significant rise in the concentrations of indole, skatole, p-methylphenol, and butyric acid in the cecum of broilers (P < 0.05). The addition of stachyose to diets reduced concentrations of indole, skatole, phenol, p-methylphenol, acetic acid and propionic acid in the cecum (P < 0.05). The lowest concentrations of indole, phenol, p-methylphenol, volatile fatty acids and pH in cecum of broilers were observed in the treatment which diet DAAA level was 1.40% with stachyose (P < 0.05). In conclusion, dietary DAAA levels and stachyose had significant interactions on the growth, main nutrient utilization and cecal odorous compounds in broilers. The dietary DAAA level was 1.54% with 5 g/kg of stachyose can improve the growth performance, nutrient utilization. However, the dietary DAAA level was 1.40% with stachyose was more beneficial to decrease the cecal odor compound composition in broilers.

Amino acid profiles: exploring their diagnostic and pathophysiological significance in hypertension.

Hypertension, a major contributor to cardiovascular morbidity, is closely linked to amino acid metabolism. Amino acids, particularly branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs), may play pivotal roles in the pathogenesis and potential management of hypertension. This review investigated the relationships between amino acid profiles, specifically BCAAs and AAAs, and hypertension, and examined their potential as diagnostic and therapeutic targets. An in-depth analysis was conducted on studies highlighting the associations of specific amino acids such as arginine, glycine, proline, glutamine, and the BCAAs and AAAs with hypertension. BCAAs and AAAs, alongside other amino acids like arginine, glycine, and proline, showed significant correlations with hypertension. These amino acids influence multiple pathways including nitric oxide synthesis, vascular remodeling, and neurotransmitter production, among others. Distinct amino acid profiles were discerned between hypertensive and non-hypertensive individuals. Amino acid profiling, particularly the levels of BCAAs and AAAs, offers promising avenues in the diagnostic and therapeutic strategies for hypertension. Future studies are crucial to confirm these findings and to delineate amino acid-based interventions for hypertension treatment.

Effect of cooking characteristics, amino acid consistency, and functional properties of composite noodles made from foxtail millet

The research endeavors to address the exigent demand for augmented nutritional efficacy in food commodities, alongside the escalating preference for expedient, superior, and health-conscious alternatives. As a result, the ongoing investigation aims to formulate instant noodles utilizing a composite blend of flours, including foxtail millet (FMF), wheat (WF), mushroom (MF), and rice bran flour (RBF), followed by a subsequent evaluation of the functional properties, cooking attributes, and amino acid composition of the noodles. The investigation considered distinct proportions of composite flour, specifically 0:100:0:0, 60:30:5:5, 50:40:5:5, and 40:50:5:5 (FMF: WF: MF: RBF), designated as treatment T1 (control), T2, T3, and T4, respectively. The results indicate that composite noodles (T2 to T4) demonstrate significantly higher water absorption indexes (ranging from 189.41 % to 197.28 %) compared to the control noodles (T1) composed solely of wheat flour (100 %), signifying an elevated capacity for water retention. Conversely, the oil absorption index of treatment T1 (214.45 %) surpassed that of treatments T2 (210.14 %), T3 (207.47 %), and T4 (200.64 %), respectively. Similarly, treatment T1 exhibited a higher swelling index (16.57 %), whereas T4 demonstrated a significantly lower swelling index with the highest water solubility (4.51 %). Additionally, the inclusion of foxtail millet flour led to a notable reduction in the optimal cooking time, with T4 requiring the shortest duration (3.45 min). Conversely, the cooking yield varied among treatments, with T4 displaying the lowest yield (42.30 %), while T1 exhibited the highest (48.72 %). Furthermore, in the comparison between control and composite noodles, treatment T4 manifested the highest levels of basic, aromatic, aliphatic, and essential amino acids. It also contained a substantial amount of lysine (11 g/100 g), nearly twice as much as treatment T1 (5 g/100 g). Organoleptic assessment indicated a preference for composite noodles (T2 to T4) in terms of taste and flavor. Therefore, fortifying foxtail millet, wheat, mushroom, and rice bran flour in a ratio of (50:40:5:5) for functional food formulations has the potential to enhance the quality of noodles.

Plasma metabolites of aromatic amino acids associate with clinical severity and gut microbiota of Parkinson’s disease

Gut microbial proteolytic metabolism has been reportedly altered in Parkinson’s disease (PD). However, the circulating aromatic amino acids (AAA) described in PD are inconsistent. Here we aimed to investigate plasma AAA profiles in a large cohort of PD patients, and examine their correlations with clinical severity and gut microbiota changes. We enrolled 500 participants including 250 PD patients and 250 neurologically normal controls. Plasma metabolites were measured using liquid chromatography mass spectrometry. Faecal samples were newly collected from 154 PD patients for microbiota shotgun metagenomic sequencing combined with data derived from 96 PD patients reported before. Data were collected regarding diet, medications, and motor and non-motor symptoms of PD. Compared to controls, PD patients had higher plasma AAA levels, including phenylacetylglutamine (PAGln), p-cresol sulfate (Pcs), p-cresol glucuronide (Pcg), and indoxyl sulfate (IS). Multivariable linear regression analyses, with adjustment for age, sex, and medications, revealed that the plasma levels of PAGln (coefficient 4.49, 95% CI 0.40–8.58, P = 0.032) and Pcg (coefficient 1.79, 95% CI 0.07–3.52, P = 0.042) positively correlated with motor symptom severity but not cognitive function. After correcting for abovementioned potential confounders, these AAA metabolites were also associated with the occurrence of constipation in PD patients (all P < 0.05). Furthermore, plasma levels of AAA metabolites were correlated with the abundance of specific gut microbiota species, including Bacteroides sp. CF01-10NS, Bacteroides vulgatus, and Clostridium sp. AF50-3. In conclusion, elevated plasma AAA metabolite levels correlated with disease characteristics in PD, suggesting that upregulated proteolytic metabolism may contribute to the pathophysiology of PD.

The effects of phenylalanine and tyrosine levels on dopamine production in rat PC12 cells. Implications for treatment of phenylketonuria, tyrosinemia type 1 and comorbid neurodevelopmental disorders

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by mutations in the phenylalanine hydroxylase (PAH) gene, resulting in phenylalanine accumulation and impaired tyrosine production. In Tyrosinemia type 1 (TYRSN1) mutations affect fumarylacetoacetate hydrolase, leading to accumulation of toxic intermediates of tyrosine catabolism. Treatment of TYRSN1 with nitisinone results in extreme tissue levels of tyrosine. Although PKU and TYRSN1 have opposite effects on tyrosine levels, both conditions have been associated with neuro-psychiatric symptoms typically present in ADHD, possibly indicating an impaired dopamine (DA) synthesis. However, concrete in vivo data on the possible molecular basis for disrupted DA production under disease mimicking conditions have been lacking. In pursuit to uncover associated molecular mechanisms, we exposed an established, DA producing cell line (PC12) to different concentrations of phenylalanine and tyrosine in culture media. We measured the effects on viability, proteomic composition, tyrosine, DA and tyrosine hydroxylase (TH) levels and TH phosphorylation. TH catalyzes the rate-limiting step in DA synthesis. High extracellular levels of phenylalanine depleted cells of intracellular tyrosine and DA. Compared to physiological levels (75 μM), either low (35 μM) or high concentrations of tyrosine (275 or 835 μM) decreased cellular DA, TH protein, and its phosphorylation levels. Using deep proteomic analysis, we identified multiple proteins, biological processes and pathways that were altered, including enzymes and transporters involved in amino acid metabolism. Using this information and published data, we developed a mathematical model to predict how extracellular levels of aromatic amino acids can affect the cellular synthesis of DA via different mechanisms. Together, these data provide new information about the normal regulation of neurotransmitter synthesis and how this may be altered in neurometabolic disorders, such as PKU and TYRSN1, with implications for the treatment of cognitive symptoms resulting from comorbid neurodevelopmental disorders.

THU585 Non-alcoholic Fatty Liver Disease (NAFLD), A Silent But Emerging Problem In Type 1 Diabetes

Abstract Disclosure: A. Taiwo: None. R. Merill: None. L. Wendt: None. D. Pape: None. H. Thakker: None. N. Pothireddy: None. B. Carlson: None. A. Sanchez: None. P. Ten Eyck: None. D. Jalal: None. A. Dokun: None. E. Taylor: None. W. Sivitz: None. Background: Non-alcoholic liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. Risk factors include type 2 diabetes, insulin resistance and obesity. Although NAFLD has been widely studied in persons with type 2 diabetes, far less in known about the pathogenesis and severity of NAFLD in type 1 diabetes. Objective: The goal of this study was to understand the metabolic perturbations that contribute to the pathogenesis of NAFLD in type 1 diabetes. Study Design: We conducted a cross-sectional study of 30 participants with type1 diabetes recruited from our institutional diabetes clinic. To assess liver fat content and stiffness, a FibroScan was done. Based on the results, participants were stratified into a case group (evidence of NAFLD) or control group (no evidence of NAFLD). All participants had fasting plasma drawn to determine metabolites. Gas-Chromatography Mass Spectrometry was used for metabolomic analyses and Liquid Chromatography Mass Spectrometry for lipidomic and acylcarnitines analyses. Results: Sixteen of 30 participants were classified as cases and 14 as controls. Cases had higher BMI (P=0.001) and were taking higher daily insulin doses than controls (P=0.008). Metabolomic analyses revealed that cases had elevated levels of glutamate (P=0.001), alanine (P=&amp;lt;0.001), pyruvate (P=&amp;lt;0.001), phenylalanine (P = 0.005), lactate (P=0.019) and anthranilic acid (P=0.029). Lipidomics revealed that, cases had elevated ceramides (P= 0.02), diacylglycerol (P=0.0003) and triacylglycerol (P=0.0003). The acylcarnitine, isovalerylcarnitine (CAR.5.0) a metabolite of isoleucine catabolism, was elevated in the cases (P = 0.010). Pathway enrichment analysis revealed, phenylalanine and tyrosine metabolism, tryptophan metabolism, glucose-alanine cycle, glutamate metabolism and glutathione metabolism were significantly enriched in the cases. Conclusion: We observed evidence of elevated metabolite levels involved in gluconeogenesis, glucose-alanine metabolism, energy metabolism, insulin resistance, and dysfunctional fat synthesis in the cases compared to controls. Our cases had some features similar to Type 2 diabetes with NAFLD, with evidence of elevated levels of aromatic amino acids, ceramides, diacylglycerol and triacylglycerol. However unlike Type 2 diabetes, there was no elevation of branched-chain amino acids levels. Presentation: Thursday, June 15, 2023

The Levels of DAHP Synthase, the First Enzyme of the Shikimate Pathway, Are Related to Free Aromatic Amino Acids and Glutamine Content in Nicotiana plumbaginifolia Cell Cultures.

Aromatic amino acid homeostasis was investigated in cell suspension cultures of Nicotiana plumbaginifolia and was related to the activity of the first enzyme in aromatic biosynthesis, 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase. An inverse relationship was found between the intracellular content of free phenylalanine, tyrosine and tryptophan and enzyme specific activity levels, suggesting the occurrence of end-product control mechanisms. Two DAHP synthase isogenes are present in wild tobacco that showed a different expression pattern during the culture growth cycle. Intracellular levels of aromatic amino acids were increased or decreased by adding the culture medium with phenylalanine, tyrosine and tryptophan, or with sublethal doses of the shikimate pathway inhibitor glyphosate, respectively. As a consequence, enzyme levels varied in the opposite direction. The concomitant exogenous supply of glutamine further reduced enzyme activity in mid-log cells, suggesting induction by both aromatic amino acid depletion and nitrogen starvation.

A Low-Protein, High-Carbohydrate Diet Exerts a Neuroprotective Effect on Mice with 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-Induced Parkinson's Disease by Regulating the Microbiota-Metabolite-Brain Axis and Fibroblast Growth Factor 21.

Parkinson's disease (PD) is closely linked to lifestyle factors, particularly dietary patterns, which have attracted interest as potential disease-modifying factors. Eating a low-protein, high-carbohydrate (LPHC) diet is a promising dietary intervention against brain aging; however, its protective effect on PD remains elusive. Here, we found that an LPHC diet ameliorated 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-induced motor deficits, decreased dopaminergic neuronal death, and increased the levels of striatal dopamine, serotonin, and their metabolites in PD mice. Levels of fibroblast growth factor 21 (FGF-21), a member of the fibroblast growth factor family, were elevated in PD mice following LPHC treatment. Furthermore, the administration of FGF-21 exerted a protective effect on MPTP-induced PC12 cells, similar to the effect of an LPHC diet in MPTP-induced mice. Sequencing of the 16S rDNA from fecal microbiota revealed that an LPHC diet normalized the gut bacterial composition imbalance in PD mice, as evidenced by the increased abundance of the genera Bifidobacterium, Ileibacterium, Turicibacter, and Blautia and decreased abundance of Bilophila, Alistipes, and Bacteroides. PICRUSt-predicted fecal microbiome function revealed that an LPHC diet suppressed lipopolysaccharide biosynthesis and the citrate cycle (TCA cycle), biosynthesis of ubiquinone and other terpenoid-quinones, and oxidative phosphorylation pathways caused by MPTP, and enhanced the biosynthesis of amino acids, carbohydrate metabolism, and biosynthesis of other secondary metabolites. A nonmetabolomic analysis of the serum and feces showed that an LPHC diet significantly increased the levels of aromatic amino acids (AAAs), including tryptophan, tyrosine, and phenylalanine. In addition, an LPHC diet elevated the serum concentrations of bile acids (BAs), particularly tauroursodeoxycholic acid (TUDCA) and taurine. Collectively, our current findings point to the potential mechanism of administering an LPHC diet in attenuating movement impairments in MPTP-induced PD mice, with AAAs, microbial metabolites (TUDCA and taurine), and FGF-21 as key mediators along the gut-microbiota-brain axis.

Differential responses in some quinoa genotypes of a consortium of beneficial endophytic bacteria against bacterial leaf spot disease.

Many effective plant-microbe interactions lead to biological changes that can stimulate plant growth and production. This study evaluated the effect of the interaction between quinoa (Chenopodium quinoa Willd.) and endophytic bacterial strains on differential responses under biotic stress. Four strains of endophytic bacteria were used to inoculate three quinoa genotypes. Endophytic bacteria, isolated from the endosphere of healthy genotypes of quinoa plants, were used to evaluate their biocontrol activity against Pseudomonas syringae on quinoa plants, which causes leaf spot disease, depending on some different parameters. Quinoa genotype plants were treated with four treatments: pathogenic bacteria only (T1), internal bacteria only (T2), pathogenic bacteria + endogenous bacteria (T3), and untreated as the control (T4). The results indicated that there was a significant difference between chlorophyll content index of infected plants without bioagent (untreated) compared to plants bio-inoculated with endophytic bacteria. The highest mean disease incidence was on the plants without bacterial inoculum (90, 80, and 100%) for quinoa genotypes G1, G2, and G3, respectively. The results showed that there were significant differences in the weight of grains/plant, as the value ranged from 8.1 to 13.3 g when treated with pathogens (T1) compared to the treatment with pathogens and endogenous bacteria (T3), which ranged from 11.7 to 18.6 g/plant. Decreases in total aromatic amino acids appeared due to the pathogen infection, by 6.3, 22.8, and 24.1% (compared to the control) in G1, G2, and G3, respectively. On the other hand, genotype G3 showed the highest response in the levels of total aromatic and total neutral amino acids. The endophytic strains promoted quinoa seedling growth mainly by improving nutrient efficiency. This improvement could not be explained by their ability to induce the production of amino acids, showing that complex interactions might be associated with enhancement of quinoa seedling performance by endophytic bacteria. The endophytic bacterial strains were able to reduce the severity of bacterial leaf spot disease by 30, 40, and 50% in quinoa genotypes G1, G2, and G3, respectively, recording significant differences compared to the negative control. The results indicated that, G1 genotype was superior in different performance indicators (pathogen tolerance index, yield injury %, superiority measure and relative performance) for grain weight/plant under pathogen infection condition when treated with endophyte bacteria. Based on this study, these bacterial strains can be used as a biotechnology tool in quinoa seedling production and biocontrol to diminish the severity of bacterial leaf spot disease.

Role of Impaired Glycolysis in Perturbations of Amino Acid Metabolism in Diabetes Mellitus.

The most frequent alterations in plasma amino acid concentrations in type 1 and type 2 diabetes are decreased L-serine and increased branched-chain amino acid (BCAA; valine, leucine, and isoleucine) levels. The likely cause of L-serine deficiency is decreased synthesis of 3-phosphoglycerate, the main endogenous precursor of L-serine, due to impaired glycolysis. The BCAA levels increase due to decreased supply of pyruvate and oxaloacetate from glycolysis, enhanced supply of NADH + H+ from beta-oxidation, and subsequent decrease in the flux through the citric acid cycle in muscles. These alterations decrease the supply of α-ketoglutarate for BCAA transamination and the activity of branched-chain keto acid dehydrogenase, the rate-limiting enzyme in BCAA catabolism. L-serine deficiency contributes to decreased synthesis of phospholipids and increased synthesis of deoxysphinganines, which play a role in diabetic neuropathy, impaired homocysteine disposal, and glycine deficiency. Enhanced BCAA levels contribute to increased levels of aromatic amino acids (phenylalanine, tyrosine, and tryptophan), insulin resistance, and accumulation of various metabolites, whose influence on diabetes progression is not clear. It is concluded that amino acid concentrations should be monitored in patients with diabetes, and systematic investigation is needed to examine the effects of L-serine and glycine supplementation on diabetes progression when these amino acids are decreased.