Disentangling the Complexity of Nutrition, Frailty and Gut Microbial Pathways during Aging: A Focus on Hippuric Acid

Hippuric acid alleviates dextran sulfate sodium-induced colitis via suppressing inflammatory activity and modulating gut microbiota

Inflammatory bowel disease (IBD) is a chronic inflammatory disease associated with metabolic disorder and gut dysbiosis. Decreased abundance of hippuric acid (HA) was found in patients with IBD. HA, metabolized directly from benzoic acid in the intestine and indirectly from polyphenols, serves as a marker of polyphenol catabolism. While polyphenols and benzoic acid have been shown to alleviate intestinal inflammation, the role of HA in this context remains unknown. Herein, we investigated the effects and mechanism of HA on DSS-induced colitis mice. The results revealed that HA alleviated clinical activity and intestinal barrier damage, decreased pro-inflammatory cytokine production. Metagenomic sequencing suggested that HA treatment restored the gut microbiota, including an increase in beneficial gut bacteria such as Adlercreutzia, Eubacterium, Schaedlerella and Bifidobacterium_pseudolongum. Furthermore, we identified 113 candidate genes associated with IBD that are potentially under HA regulation through network pharmacological analyses. 10 hub genes including ALB, IL-6, HSP90AA1, and others were identified using PPI analysis and validated using molecular docking and mRNA expression analysis. Additionally, KEGG analysis suggested that the renin-angiotensin system (RAS), NF-κB signaling and Rap1 signaling pathways were important pathways in the response of HA to colitis. Thus, HA may provide novel biotherapy options for IBD.

Microbial Community and Metabolome Analysis of the Porcine Intestinal Damage Model Induced by the IPEC-J2 Cell Culture-Adapted Porcine Deltacoronavirus (PDCoV) Infection

This study was conducted to elucidate the intestinal damage induced by the IPEC-J2 cell culture-passaged PDCoV. The results showed that PDCoV disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, PDCoV induced an imbalance in the intestinal flora and disturbed its stability. Microbial community profiling revealed bacterial enrichment (e.g., Proteobacteria) and reduction (e.g., Firmicutes and Bacteroidetes) in the PDCoV-inoculated piglet model. In addition, metabolomics analysis indicated that 82 named differential metabolites were successfully quantified, including 37 up-regulated and 45 down-regulated metabolites. Chenodeoxycholic acid, sphingosine, and oleanolic aldehyde levels were reduced in PDCoV-inoculated piglets, while phenylacetylglycine and geranylgeranyl-PP levels were elevated. Correlation analysis indicated a negative correlation between Escherichia-Shigella and choline, succinic acid, creatine, phenyllactate, and hippuric acid. Meanwhile, Escherichia-Shigella was positively correlated with acetylcholine, L-Glutamicacid, and N-Acetylmuramate. Roseburia, Lachnospiraceae_UCG-010, Blautia, and Limosilactobacillus were negatively and positively correlated with sphingosine, respectively. These data suggested PDCoV-inoculated piglets exhibited significant taxonomic perturbations in the gut microbiome, which may result in a significantly altered metabolomic profile.

Metabolomic Markers in Attention-Deficit/Hyperactivity Disorder (ADHD) among Children and Adolescents-A Systematic Review

Attention-Deficit/Hyperactivity Disorder (ADHD), characterized by clinical diversity, poses diagnostic challenges often reliant on subjective assessments. Metabolomics presents an objective approach, seeking biomarkers for precise diagnosis and targeted interventions. This review synthesizes existing metabolomic insights into ADHD, aiming to reveal biological mechanisms and diagnostic potentials. A thorough PubMed and Web of Knowledge search identified studies exploring blood/urine metabolites in ADHD-diagnosed or psychometrically assessed children and adolescents. Synthesis revealed intricate links between ADHD and altered amino acid metabolism, neurotransmitter dysregulation (especially dopamine and serotonin), oxidative stress, and the kynurenine pathway impacting neurotransmitter homeostasis. Sleep disturbance markers, notably in melatonin metabolism, and stress-induced kynurenine pathway activation emerged. Distinct metabolic signatures, notably in the kynurenine pathway, show promise as potential diagnostic markers. Despite limitations like participant heterogeneity, this review underscores the significance of integrated therapeutic approaches targeting amino acid metabolism, neurotransmitters, and stress pathways. While guiding future research, this overview of the metabolomic findings in ADHD suggests directions for precision diagnostics and personalized ADHD interventions.

Metabolomic Analysis Reveals the Association of Severe Bronchopulmonary Dysplasia with Gut Microbiota and Oxidative Response in Extremely Preterm Infants

Bronchopulmonary dysplasia (BPD) is a chronic lung disease mainly affecting premature infants needing ventilation or oxygen for respiratory distress. This study aimed to evaluate the molecular linkages for BPD in very and extremely preterm infants using a metabolomics-based approach. A case-control study of enrolling preterm infants born before 32 weeks gestational age (GA) was prospectively performed. These preterm infants were subsequently stratified into the following two groups for further analysis: no or mild BPD, and moderate or severe BPD based on the 2019 NICHD criteria. Urinary metabolomic profiling was performed using 1H-Nuclear magnetic resonance (NMR) spectroscopy coupled with partial least squares discriminant analysis (PLS-DA) at a corrected age of 6 months. Metabolites significantly differentially related to GA and BPD severity were performed between groups, and their roles in functional metabolic pathways were also assessed. A total of 89 preterm infants born before 32 weeks gestation and 50 infants born at term age (above 37 completed weeks' gestation) served as controls and were enrolled into the study. There were 21 and 24 urinary metabolites identified to be significantly associated with GA and BPD severity, respectively (p < 0.05). Among them, N-phenylacetylglycine, hippurate, acetylsalicylate, gluconate, and indoxyl sulfate were five metabolites that were significantly higher, with the highest importance in both infants with GA < 28 weeks and those with moderate to severe BPD, whereas betaine and N,N-dimethylglycine were significantly lower (p < 0.05). Furthermore, ribose and a gluconate related pentose phosphate pathway were strongly associated with these infants (p < 0.01). In conclusion, urinary metabolomic analysis highlights the crucial role of gut microbiota dysbiosis in the pathogenesis of BPD in preterm infants, accompanied by metabolites related to diminished antioxidative capacity, prompting an aggressive antioxidation response in extremely preterm infants with severe BPD.

The interaction between Mediterranean diet and intestinal microbiome: relevance for preventive strategies against frailty in older individuals

Age-related changes in intestinal microbiome composition and function are increasingly recognized as pivotal in the pathophysiology of aging and are associated with the aging phenotype. Diet is a major determinant of gut-microbiota composition throughout the entire lifespan, and several of the benefits of a healthy diet in aging could be mediated by the microbiome. Mediterranean diet (MD) is a traditional dietary pattern regarded as the healthy diet paradigm, and a large number of studies have demonstrated its benefits in promoting healthy aging. MD has also a positive modulatory effect on intestinal microbiome, favoring bacterial taxa involved in the synthesis of several bioactive compounds, such as short-chain fatty acids (SCFAs), that counteract inflammation, anabolic resistance, and tissue degeneration. Intervention studies conducted in older populations have suggested that the individual response of older subjects to MD, in terms of reduction of frailty scores and amelioration of cognitive function, is significantly mediated by the gut-microbiota composition and functionality. In this context, the pathophysiology of intestinal microbiome in aging should be considered when designing MD-based interventions tailored to the needs of geriatric patients.

Benzoic acid supplementation improves the growth performance, nutrient digestibility and nitrogen metabolism of weaned lambs

Nitrogen is one of the essential components of proteins and nucleic acids and plays a crucial role in the growth and development of ruminants. However, the nitrogen utilization rate of ruminants is lower than that of monogastric animals, which not only reduces protein conversion and utilization, but also increases manure nitrogen discharge as well as causing environmental pollution. The lamb stage is an important period in the life of sheep, which can affect the production performance and meat quality of fattening sheep. The purpose of this experiment was to explore effects of benzoic acid supplementation on growth performance, nutrient digestibility, nitrogen metabolism and plasma parameters of weaned lambs. A total of 40 weaned male Hu sheep lambs with similar body weight were randomly divided into 4 groups: control with no benzoic acid (0 BA) and the lambs in other 3 groups were fed 0.5, 1, and 1.5% benzoic acid on the basis of experimental diet (0.5, 1, and 1.5 BA, respectively). The experiment lasted for 60 days. Results showed that the average daily gain of 1 BA group was significantly increased (p < 0.05) when compared to 0 and 1.5 BA groups, while an opposite tendency of dry matter intake to average daily gain ratio was observed. The dry matter, organic matter, neutral detergent fiber and acid detergent fiber digestibility of 1 BA group was significantly increased (p < 0.05) as compared with 0 and 1.5 BA groups as well as plasma albumin content. Also, the urinary hippuric acid and hippurate nitrogen concentrations in 1 and 1.5 BA groups were higher (p < 0.05) than those in 0 and 0.5 BA groups. Additionally, the nitrogen intake in 0.5 and 1 BA groups was significantly increased (p < 0.05) when compared to other groups. At 1 h after morning feeding, the plasma benzoic acid concentration of 1 BA group reached up to maximum value and was higher (p < 0.05) than other groups, and then began to decrease. Similarly, the hippuric acid concentration in plasma of 1 and 1.5 BA groups was higher (p < 0.05) than that of 0 BA group from 1 to 4 h post morning feeding. At 3 h after feeding, the urea nitrogen concentration in plasma of 0 BA group was higher (p < 0.05) than that of 1.5 BA group. Overall, the appropriate supplementation of benzoic acid (1%) in the diet can improve growth performance and nitrogen metabolism of weaned lambs.

Combination of Lacticaseibacillus paracasei BEPC22 and Lactiplantibacillus plantarum BELP53 attenuates fat accumulation and alters the metabolome and gut microbiota in mice with high-fat diet-induced obesity

This study evaluated the effects of formulations with Lacticaseibacillus paracasei BEPC22 and Lactiplantibacillus plantarum BELP53 on adiposity, the alteration of microbiota, and the metabolome in high-fat diet-fed mice. The strains were selected based on their fat and glucose absorption inhibitory activities and potential metabolic interactions. The optimal ratio of the two strains in the probiotic formulation was determined based on their adipocyte differentiation inhibitory activities. Treatment of formulations with BEPC22 and BELP53 for 10 weeks decreased body weight gain at 6 weeks; it also decreased the food efficiency ratio, white adipose tissue volume, and adipocyte size. Moreover, it decreased the expression of the lipogenic gene Ppar-γ in the liver, while significantly increasing the expression of the fat oxidation gene Ppar-α in the white adipose tissue. Notably, treatment with a combination of the two strains significantly reduced the plasma levels of the obesity hormone leptin and altered the microbiota and metabolome. The omics data also indicated the alteration of anti-obesity microbes and metabolites such as Akkermansia and indolelactic acid, respectively. These findings suggest that treatment with a combination of BEPC22 and BELP53 exerts synergistic beneficial effects against obesity.

Exploring the Occurrence Mechanism and Early-Warning Model of Phlebitis Induced by Aescinate Based on Metabolomics in Cerebral Infarction Patients

Objective

This study aims to explore the mechanism underlying the induction of phlebitis by aescinate and create an early-warning model of phlebitis based on metabolomics.

Methods

Patients with cerebral infarction enrolled had been treated with aescinate. Plasma samples were collected either before administration of aescinate, upon the occurrence of phlebitis, or at the end of treatment. Non-targeted metabolomics and targeted amino acid metabolomics were carried out to analyze metabolic profiles and quantify the metabolites.

Results

Untargeted metabolomics revealed six differential metabolites in baseline samples versus post-treatment samples and four differential metabolites in baseline samples from patients with or without phlebitis. Pathways of these differential metabolites were mainly enriched in amino acid metabolism. Ten differential amino acids with a VIP value of >1 were identified in the baseline samples, enabling us to distinguish between patients with or without phlebitis. A logistic regression model was constructed (AUC 0.825) for early warning of phlebitis of grade 2 or higher.

Conclusion

The occurrence of aescinate-induced phlebitis, which can be predicted early during onset, may be associated with perturbations of the endogenous metabolic profile, especially the metabolism of amino acids.

Metabolic profiling of Alzheimer's disease: Untargeted metabolomics analysis of plasma samples

Alzheimer's disease (AD) is often not recognized or is diagnosed very late, which significantly reduces the effectiveness of available pharmacological treatments. Metabolomic analyzes have great potential for improving existing knowledge about the pathogenesis and etiology of AD and represent a novel approach towards discovering biomarkers that could be used for diagnosis, prognosis, and therapy monitoring. In this study, we applied the untargeted metabolomic approach to investigate the changes in biochemical pathways related to AD pathology. We used gas chromatography and liquid chromatography coupled to mass spectrometry (GC-MS and LC-MS, respectively) to identify metabolites whose levels have changed in subjects with AD diagnosis (N = 40) compared to healthy controls (N = 40) and individuals with mild cognitive impairment (MCI, N = 40). The GC-MS identified significant differences between groups in levels of metabolites belonging to the classes of benzene and substituted derivatives, carboxylic acids and derivatives, fatty acyls, hydroxy acids and derivatives, keto acids and derivatives, and organooxygen compounds. Most of the compounds identified by the LC-MS were various fatty acyls, glycerolipids and glycerophospholipids. All of these compounds were decreased in AD patients and in subjects with MCI compared to healthy controls. The results of the study indicate disturbed metabolism of lipids and amino acids and an imbalance of metabolites involved in energy metabolism in individuals diagnosed with AD, compared to healthy controls and MCI subjects.

Quantification and holistic quality evaluation of Wulingzhi extract by UHPLC-Q-Orbitrap-HRMS coupled with chemometric approaches

The excreta of Trogopterus xanthipes ("Wulingzhi" in Chinese, WLZ) is a well-known traditional Chinese medicine. It has been used for centuries to treat amenorrhea, menstruation and postpartum abdominal pain. However, a systematic quality study on WLZ chemical markers has yet to be conducted. This study aimed to establish an ultra-high-performance liquid chromatography coupled with a hybrid quadruple extraction Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS) method for the simultaneous quantitative determination of 20 compounds in 53 batches of WLZ; the method rapidly and sensitively determined the 20 plant- or animal-derived compounds. Firstly, the proposed approach was validated to satisfy the method's linearity, detection limits, precision, repeatability, stability and accuracy. Subsequently, multivariate analysis was used to identify correlations between the samples and feed, processing and regions. Finally, this method was used to further identify chemical markers for quality control in combination with chemometrics. This is the first report on pinusolide, betaine, hippuric acid, 4-oxorentinoic acid, 15-methoxypinusolidic acid and 4-oxoisotrentinoin in WLZ; the quality of WLZ became homogeneous after processing with vinegar (V-WLZ). Moreover, we screened for potential component markers, including uridine, allantoin, amentoflavone, hippuric acid, 3,4-dihydroxybenzoic acid, pinusolide, quercetin and kaempferol. These results were practical and efficient for the chemical clarification of WLZ and V-WLZ.

A New Biomarker Profiling Strategy for Gut Microbiome Research: Valid Association of Metabolites to Metabolism of Microbiota Detected by Non-Targeted Metabolomics in Human Urine

The gut microbiome is of tremendous relevance to human health and disease, so it is a hot topic of omics-driven biomedical research. However, a valid identification of gut microbiota-associated molecules in human blood or urine is difficult to achieve. We hypothesize that bowel evacuation is an easy-to-use approach to reveal such metabolites. A non-targeted and modifying group-assisted metabolomics approach (covering 40 types of modifications) was applied to investigate urine samples collected in two independent experiments at various time points before and after laxative use. Fasting over the same time period served as the control condition. As a result, depletion of the fecal microbiome significantly affected the levels of 331 metabolite ions in urine, including 100 modified metabolites. Dominating modifications were glucuronidations, carboxylations, sulfations, adenine conjugations, butyrylations, malonylations, and acetylations. A total of 32 compounds, including common, but also unexpected fecal microbiota-associated metabolites, were annotated. The applied strategy has potential to generate a microbiome-associated metabolite map (M3) of urine from healthy humans, and presumably also other body fluids. Comparative analyses of M3 vs. disease-related metabolite profiles, or therapy-dependent changes may open promising perspectives for human gut microbiome research and diagnostics beyond analyzing feces.

The plasma metabolome of long COVID patients two years after infection

One of the major challenges currently faced by global health systems is the prolonged COVID-19 syndrome (also known as "long COVID") which has emerged as a consequence of the SARS-CoV-2 epidemic. It is estimated that at least 30% of patients who have had COVID-19 will develop long COVID. In this study, our goal was to assess the plasma metabolome in a total of 100 samples collected from healthy controls, COVID-19 patients, and long COVID patients recruited in Mexico between 2020 and 2022. A targeted metabolomics approach using a combination of LC-MS/MS and FIA MS/MS was performed to quantify 108 metabolites. IL-17 and leptin were measured in long COVID patients by immunoenzymatic assay. The comparison of paired COVID-19/long COVID-19 samples revealed 53 metabolites that were statistically different. Compared to controls, 27 metabolites remained dysregulated even after two years. Post-COVID-19 patients displayed a heterogeneous metabolic profile. Lactic acid, lactate/pyruvate ratio, ornithine/citrulline ratio, and arginine were identified as the most relevant metabolites for distinguishing patients with more complicated long COVID evolution. Additionally, IL-17 levels were significantly increased in these patients. Mitochondrial dysfunction, redox state imbalance, impaired energy metabolism, and chronic immune dysregulation are likely to be the main hallmarks of long COVID even two years after acute COVID-19 infection.

Quantitative, Targeted Analysis of Gut Microbiota Derived Metabolites Provides Novel Biomarkers of Early Diabetic Kidney Disease in Type 2 Diabetes Mellitus Patients

Diabetic kidney disease (DKD) is one of the most debilitating complications of type 2 diabetes mellitus (T2DM), as it progresses silently to end-stage renal disease (ESRD). The discovery of novel biomarkers of early DKD becomes acute, as its incidence is reaching catastrophic proportions. Our study aimed to quantify previously identified metabolites from serum and urine through untargeted ultra-high-performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight-mass spectrometry (UHPLC-QTOF-ESI+-MS) techniques, such as the following: arginine, dimethylarginine, hippuric acid, indoxyl sulfate, p-cresyl sulfate, L-acetylcarnitine, butenoylcarnitine and sorbitol. The study concept was based on the targeted analysis of selected metabolites, using the serum and urine of 20 healthy subjects and 90 T2DM patients with DKD in different stages (normoalbuminuria-uACR < 30 mg/g; microalbuminuria-uACR 30-300 mg/g; macroalbuminuria-uACR > 300 mg/g). The quantitative evaluation of metabolites was performed with pure standards, followed by the validation methods such as the limit of detection (LOD) and the limit of quantification (LOQ). The following metabolites from this study resulted as possible biomarkers of early DKD: in serum-arginine, dimethylarginine, hippuric acid, indoxyl sulfate, butenoylcarnitine and sorbitol and in urine-p-cresyl sulfate.

Accounting Gut Microbiota as the Mediator of Beneficial Effects of Dietary (Poly)phenols on Skeletal Muscle in Aging

Sarcopenia, the age-related loss of muscle mass and function increasing the risk of disability and adverse outcomes in older people, is substantially influenced by dietary habits. Several studies from animal models of aging and muscle wasting indicate that the intake of specific polyphenol compounds can be associated with myoprotective effects, and improvements in muscle strength and performance. Such findings have also been confirmed in a smaller number of human studies. However, in the gut lumen, dietary polyphenols undergo extensive biotransformation by gut microbiota into a wide range of bioactive compounds, which substantially contribute to bioactivity on skeletal muscle. Thus, the beneficial effects of polyphenols may consistently vary across individuals, depending on the composition and metabolic functionality of gut bacterial communities. The understanding of such variability has recently been improved. For example, resveratrol and urolithin interaction with the microbiota can produce different biological effects according to the microbiota metabotype. In older individuals, the gut microbiota is frequently characterized by dysbiosis, overrepresentation of opportunistic pathogens, and increased inter-individual variability, which may contribute to increasing the variability of biological actions of phenolic compounds at the skeletal muscle level. These interactions should be taken into great consideration for designing effective nutritional strategies to counteract sarcopenia.