Serum Metabolites Research Articles

Genetic insights into the effect of trace elements on cardiovascular diseases: multi-omics Mendelian randomization combined with linkage disequilibrium score regression analysis

ObjectiveEpidemiological evidence indicates that trace elements are significantly associated with cardiovascular health. However, its causality and underlying mechanisms remain unclear. Therefore, this study aimed to investigate the causal relationship between trace elements and cardiovascular disease, as well as their potential mechanism of action.MethodTwo-sample Mendelian randomization (MR) analyses along with mediated and multivariate MR analyses were employed. These analyses utilized 13 trace elements as exposure variables and 20 cardiovascular diseases as outcome variables, with 4907 circulating plasma proteins, 1400 serum metabolites, 731 immune cell phenotypes, and 473 intestinal flora as potential mediators. The Bayesian weighted MR method was used to validate the MR results, and linkage disequilibrium score regression (LDSC) was applied to explore the genetic correlation between trace elements and cardiovascular disease.ResultOur findings indicated a positive or negative causal relationship between genetically predicted trace elements and cardiovascular disease. An analysis using the Bayesian weighted MR method demonstrated that our causal inference results were reliable. The results of the mediated MR analyses indicate that potassium may reduce the risk of ischemic heart disease by influencing the expression of the plasma proteins BDH2 and C1R. Vitamin B12 may increase the risk of coronary atherosclerosis and cardiovascular death by reducing the levels of VPS29 and PSME1 proteins, while vitamin C may mitigate the risk of cardiac arrest by inhibiting the expression of the TPST2 protein. In addition, potassium can reduce the risk of ischemic heart disease by lowering 4-methoxyphenyl sulfate levels. None of the instrumental variables exhibited pleiotropy in the MR analysis. A sensitivity analysis using the leave-one-out method further confirmed the robustness of our findings. LDSC results indicated a genetic correlation between multiple trace elements and various cardiovascular diseases.ConclusionThis study uncovered the true causal relationship between trace elements and cardiovascular disease risk using genetic methods, and revealed the significant mediating role of specific plasma proteins and metabolites in this relationship.

Inhibitory effect of Zhujing Pill on myopia progression: Mechanistic insights based on metabonomics and network pharmacology.

This study endeavored to uncover the mechanisms by which Zhujing pill (ZJP) slows myopia progression. We employed biometric analyses to track diopter and axial length changes in guinea pigs with negative lens-induced myopia (LIM). Through integrating metabonomics and network pharmacology, we aimed to predict the anti-myopic targets and active ingredients of ZJP. Subsequent analysis, including real-time fluorescent quantitative PCR (qPCR) and Western blotting (WB), assessed the expression levels of CHRNA7, LPCAT1, and NOS2 in retinal tissues. Our findings demonstrate that ZJP significantly mitigates diopter increase and axial elongation in LIM guinea pigs. Metabonomic analysis revealed significant changes in 13 serum metabolites, with ZJP reversing the expression of 5 key metabolites. By integrating metabonomics with network pharmacology, we identified core targets of ZJP against myopia and constructed a compound-gene-disease-metabolite network. The expressions of LPCAT1 and CHRNA7 were found to decrease in the LIM group but increase with ZJP treatment, whereas NOS2 expression showed the opposite pattern. This investigation provides the first evidence of ZJP's multifaceted effectiveness in managing myopia, highlighting its impact on multiple components, targets, and pathways, including the novel involvement of LPCAT1 and CHRNA7 in myopia pathogenesis.

Therapeutic potential of Xihuang Pill in colorectal cancer: Metabolomic and microbiome-driven approaches

IntroductionThe Xihuang Pill (XHP), a venerated traditional Chinese medicine, has demonstrated significant anti-cancer capabilities. Despite its proven efficacy, the scarcity of comprehensive pharmacological studies limits the widespread application of XHP. This research endeavor seeks to demystify the therapeutic underpinnings of XHP, particularly in the realm of colorectal cancer (CRC) therapy.MethodsIn this study, mice harboring CT26 tumors were divided into four groups, each administered with either XHP monotherapy, 5-fluorouracil (5-FU), or a combination of both. The tumor growth trajectory was closely monitored to evaluate the effectiveness of these anti-neoplastic interventions. Advanced techniques, including 16S-rDNA gene sequencing and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), were harnessed to scrutinize the gut microbiota and serum metabolite profiles. Immunohistochemical assays were employed to gauge the expression levels of CD4, CD8, and Foxp3, thereby providing insights into the dynamics of tumor-infiltrating lymphocytes within the tumor microenvironment.ResultsOur findings indicate that XHP effectively suppresses the initiation and progression of colorectal tumors. The combinatorial therapy of XHP with 5-FU exhibited an enhanced inhibitory effect on tumor growth. Metabolic profiling revealed that XHP induced notable metabolic shifts, particularly impacting pathways such as steroid hormone synthesis, arachidonic acid metabolism, purine biosynthesis, and renin secretion. Notably, 17α-ethinyl estradiol and α-ergocryptine were identified as serum metabolites with the most substantial increase following XHP administration. Analysis of the gut microbiome suggested that XHP promoted the expansion of specific bacterial taxa, including Lachnospiraceae_NK4A136_group, Clostridiales, Desulfovibrionaceae, and Anaerotignum_sp., while suppressing the proliferation of others such as Ligilactobacilus, Lactobacillus_taiwanensis, and Candidatus_saccharimonas. Immunohistochemical staining indicated an upregulation of CD4 and CD8 post-XHP treatment.ConclusionThis study delineates a potential mechanism by which XHP inhibits CRC tumorigenesis through modulating the gut microbiota, serum metabolites, and reshaping the tumor immune microenvironment in a murine CRC model. These findings contribute to a more profound understanding and potentially broaden the clinical utility of XHP in oncology.

Pentachlorophenol increases diabetes risk by damaging β-cell secretion and disrupting gut microbial-related amino acids and fatty acids biosynthesis

Pentachlorophenol (PCP), a ubiquitous environmental pollutant, has been reported as a possible contributor to diabetes. However, evidence for general population is scarce while related mechanisms are largely unknown. Using a representative population-based case-control study in Beijing (n=1796), we found a positive association between PCP exposure and diabetes risk with the odds ratio reaching 1.68 (95% confidence interval: 1.30 to 2.18). A further rat experiment revealed that low-dose PCP mimicking real-world human exposure can significantly impair glycemic homeostasis by inducing pancreatic β-cell dysfunction, with non-linear dose-response relationships. Subsequent multi-omics analysis suggested that low-dose PCP led to notable gut microbiota dysbiosis (especially the species from genus Prevotella, such as intermedia, dentalis, ruminicola, denticola, melaninogenica, and oris), decreased serum amino acids (L-phenylalanine, L-tyrosine, and L-tryptophan) and increased serum fatty acids (oleic and palmitic acid) in rats, while strong correlations were observed among alterations of gut microbes, serum metabolites and glycemic-related biomarkers (e.g., fasting blood glucose and insulin). Collectively, these results imply PCP may increase diabetes risk by disrupting gut microbial-related amino acids and fatty acids biosynthesis. This will help guide future in-depth studies on the roles of PCP in the development of human diabetes.

Multi-omics mechanical analysis of gut microbiota, carboxylic acids, and cardiac gene expression interaction triggering diabetic cardiomyopathy.

Our research results clearly link the changes in heart genes of T2DM and normal mice with changes in serum metabolites and gut microbiota, indicating that some genes in biological processes are closely related to the reduction of protective microbiota in the gut microbiota. This study provides a theoretical basis for investigating the mechanism of DCM and may provide preliminary evidence for the future use of gut microbiota therapy for DCM.

Editorial: Serum metabolites in diagnostics and therapeutics

Editorial: Serum metabolites in diagnostics and therapeutics

Apparent total tract nutrient digestibility of frozen raw, freeze-dried raw, fresh, and extruded dog foods and their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs

Abstract Various pet food diet formats are available, but many are poorly studied. The objective of this study was to determine the apparent total tract macronutrient digestibility (ATTD) of frozen raw, freeze-dried raw, fresh, and extruded dog foods and assess their effects on serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Ten beagle dogs (4.10 ± 0.74 yr) were used in a replicated 5x5 Latin square study to test the following diets: Chicken and Barley Recipe [extruded; Hill’s Science Diet (EXT)], Chicken and White Rice Recipe [fresh; Just Food for Dogs (FRSH)], Chicken Formula [frozen raw; Primal (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [freeze-dried raw; Primal (HFD)], and Chicken Dinner Patties [freeze-dried raw; Stella & Chewy’s (FD)]. The experiment was composed of five 35-d periods, with each ending with fecal and blood collections. Data were analyzed using Mixed Models in SAS 9.4, with P<0.05 being significant. Treatment was a fixed effect and dog a random effect. Protein ATTD was higher for FRZN and FD than other diets and higher for HFD than FRSH and EXT. Fat ATTD was higher for HFD than FRZN and EXT and lower for EXT than other diets. Fecal output was higher for dogs fed EXT than those fed other diets and higher for dogs fed FRSH than those fed FRZN, HFD, or FD. Fecal pH was lower in dogs fed EXT and FRSH than those fed other diets. Fecal scores were higher (looser) in dogs fed EXT and FRSH than those fed FRZN and FD. Fecal dry matter was higher in dogs fed FD than those fed other diets and higher in those fed FRZN and HFD than those fed EXT and FRSH. In general, fecal short-chain fatty acids were highest in dogs fed EXT, intermediate in dogs fed FRSH and HFD, and lowest in dogs fed FRZN and FD. Fecal isobutyrate and isovalerate were highest in dogs fed HFD, lowest in dogs fed FRSH, and intermediate in dogs fed other diets. Fecal primary bile acids were higher, while secondary bile acids were lower in dogs fed FRSH than in dogs fed other diets. Fecal microbiota were greatly impacted by diet, with alpha diversity, beta diversity, and relative abundances of over 40 bacterial genera being different among treatments. This study shows that dietary format may lead to great differences in nutrient digestibility and fecal characteristics, metabolites, and microbiota. More research is needed to distinguish the effects of ingredient source, processing method, and nutrient composition.

Causal effects of gut microbiota on gout and hyperuricemia: insights from genome-wide Mendelian randomization, RNA-sequencing, 16S rRNA sequencing, and metabolomes.

This study investigated the causal relationship between gut microbiota (GM), serum metabolome, and host transcriptome in the development of gout and hyperuricemia (HUA) using genome-wide association studies (GWAS) data and HUA mouse model experiments. Mendelian randomization (MR) analysis of GWAS summary statistics was performed using an inverse variance weighted (IVW) approach to determine or predict the causal role of the GM on gout. The HUA mouse model was used to characterize changes in the gut microbiome, host metabolome, and host kidney transcriptome by integrating cecal 16S rRNA sequencing, untargeted serum metabolomics, and host mRNA sequencing. Our analysis demonstrated causal effects of seven GM taxa on gout, including genera of Ruminococcus, Odoribacter, and Bacteroides. Thirty eight immune cell traits were associated with gout. Dysbiosis of Dubosiella, Lactobacillus, Bacteroides, Alloprevotella, and Lachnospiraceae_NK4A136_group genera were associated with changes in the serum metabolites and kidney transcriptome of the HUA model mice. The changes in the gut microbiome of the HUA model mice correlated significantly with alterations in the levels of serum metabolites such as taurodeoxycholic acid, phenylacetylglycine, vanylglycol, methyl hexadecanoic acid, carnosol, 6-aminopenicillanic acid, sphinganine, p-hydroxyphenylacetic acid, pyridoxamine, and de-o-methylsterigmatocystin, and expression of kidney genes such as CNDP2, SELENOP, TTR, CAR3, SLC12A3, SCD1, PIGR, CD74, MFSD4B5, and NAPSA. Our study demonstrated a causal relationship between GM, immune cells, and gout. HUA development involved alterations in the vitamin B6 metabolism because of GM dysbiosis that resulted in altered pyridoxamine and pyridoxal levels, dysregulated sphingolipid metabolism, and excessive inflammation.

Effect of "Xingshen-Jieyu" electroacupuncture on serum differential metabolites in patients with depression based on metabolomics

To explore the effect of "Xingshen-Jieyu" (inducing resuscitation and dispel ling melancholy) electroacupuncture (EA) on serum metabolites in patients with depression and its underlying mechanisms through serum non-targeted metabolomics. Fifteen depression patients were subjected into the EA group, and 15 healthy volunteers were matched into the healthy group. EA (2 Hz/15 Hz, a tolerable strength) was applied to Baihui (GV20), Shenting (GV24), Toulinqi (GB15), Benshen (GB13), Touwei (ST8), Xuanli (GB6) and Qubin (GB7) for 30 min, 3 times a week for 6 weeks. The severity of depression was assessed using Hamilton Depression Scale-17 (HAMD-17) and Hamilton Anxiety Scale (HAMA), the degree of fatigue was evaluated using Fatigue Scale-14 (FS-14). The subjects sleep quality was assessed using Pittsburgh sleep quality index (PSQI). Blood samples were collected before and after the treatment for processing serum to perform non-targeted metabolomics profile detection using ultra-high-performance liquid chromatography coupled with mass spectrometry (UPLC-MS), and Partial Least Squares Discriminant Analysis (PLS-DA, a statistical approach). Differential metabolites were screened and pathway enrichment analysis was performed. After the treatment, the scores of HAMD-17, HAMA, PSQI and FS-14 of depression patients were significantly lowered in the EA group (P<0.05). Compared with the healthy subjects, 46 differential metabolites (21 up-regulated, 25 down-regulated) were screened in patients with depression. Compared with pre-treatment in the EA group, 19 differential (17 up-regulated, and 2 down-regulated) metabolites were screened. Four down-regulated metabolites of the 46 differential metabolites in depression patients were recovered after EA treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differential metabolites before and after EA showed that 19 metabolic pathways were enriched, mainly involving glutaminergic synapses, GABAergic synapses and several amino acid metabolism related pathways. "Xingshen-Jieyu" EA mainly regulates the metabolism of amino acids, and activities of neurotransmitter glutamate and GABA, and restores the excitatory/inhibitory balance, thus playing a role in improving depression.

Serum metabolic profiles in quails: Effects of age, breed, and sex

Over the past decade, metabolomic research in livestock and poultry has gained considerable momentum; however, quail metabolomics still lags behind that of livestock species such as chickens, pigs, and cattle. Quails are important models due to their low-cost protein sources—both eggs and meat—and practical benefits such as minimal space requirements, high egg production, disease resistance, and rapid reproduction. Therefore, it is necessary to systematically understand the effects of various factors on quail metabolism to provide a theoretical basis for accurate feeding and breeding practices. In this study, liquid chromatography with tandem mass spectroscopy (LC-MS/MS)-based metabolomics was used to examine the effects of age, breed, and sex on the serum metabolic profile of quails. A total of 550 metabolites were identified. Relative to breed and sex, we found that age played a crucial role in influencing quail serum metabolites. At 20 days of age (D20), quails had high levels of serum thymidine and alpha-D-glucose, while at 70 days of age (D70), the lipids, including 3-isothujone, 15-deoxy-d-12,14-PGJ2, and 2-aminobut-2-enoate dominated the serum. Additionally, xanthine, hypoxanthine, diaminopimelic acid, and 2-deoxy-scyllo-inosose appeared to be specific metabolites of Japanese quail (JAPQ). Serum levels of N-acetylglutamic acid, hydroxypyruvic acid, carnosine, alloepipregnanolone, lumichrome, 6-hydroxynicotinate, and myristic acid were higher in D70 Hengyan white feather quails (HYWQ) than those in D70 JAPQ. Notably, this study also identified 2-hydroxy-2-ethylsuccinic acid and riboflavin as potential specific metabolites in female quails. Furthermore, integration analysis showed that amino acid biosynthesis and metabolism, as well as ABC transporters, were the key pathways distinguishing D20 from D70. Purine metabolism, pyrimidine metabolism, ABC transporters, and TCA cycle were the key pathways distinguishing HYWQ from JAPQ. Differences in energy metabolism and amino acid biosynthesis and metabolism were observed between males and females. These findings enhance our understanding of the dynamic changes in quail serum metabolites influenced by various factors and address the knowledge gap regarding serum metabolic changes at different stages in quails.

Interpretation of the pathogenesis and therapeutic mechanisms of first-episode major depressive disorder based on multiple amino acid metabolic pathways: a metabolomics study.

Given the unclear etiology and treatment mechanisms of depression, we aim to explore the metabolic differences between patients with major depressive disorder (MDD) and the healthy population, as well as before and after treatment with escitalopram (ESC). Recruit first-episode drug-naïve MDD (DN-MDD) patients and healthy controls (HCs). Clinical data and serum samples from all subjects were collected at baseline and patients' samples were collected again after ESC monotherapy for four weeks. Perform non-targeted metabolomic analysis and apply MetaboAnalyst 5.0 to identify differential metabolites and execute KEGG pathway enrichment. Through metabolomic analysis of serum samples, 904 differential metabolites were identified in the DN-MDD group compared to the HCs, and 455 metabolites in treated patients compared to DN-MDD patients. In the pathway analysis, DN-MDD state regulated functions of histidine, beta-alanine, aspartate, and tryptophan metabolism, while ESC treatment produced an influence on the biological process of aspartate and sphingolipid. We respectively depicted metabolism-related biomolecular changes in the serum of patients suffering from MDD and undergoing ESC treatment. Multiple amino acid metabolism pathways were adjusted in MDD patients, and levels of aspartate, arginine and sphingolipids were regulated after ESC monotherapy. These biomolecular changes may bring new insights into the biology and treatment of MDD from the perspective of the serum metabolites.

Type 1 Diabetes and Cataracts: Investigating Mediating Effects of Serum Metabolites Using Bidirectional Mendelian Randomization.

To investigate the causal relationship between type 1 diabetes (T1D) and cataracts and to explore the mediating role of serum metabolites. This study employed bidirectional Mendelian randomization (MR) using genetic variants as instrumental variables to infer causality in both directions: from T1D to cataracts and cataracts to T1D. Genetic data for T1D, its complications, and cataracts were sourced from independent genome-wide association study (GWAS) datasets. A two-step multivariable MR combined with mediation analysis was conducted to evaluate the indirect effects of serum metabolites in the causal pathway from T1D to cataracts. The MR analysis demonstrated a significant causal association between T1D and an increased risk of cataracts (OR = 1.01-1.05; p < 0.05). Further analysis showed that patients with T1D complications such as coma, ketoacidosis, nephropathy, and retinopathy exhibited a significantly higher risk of developing cataracts compared to those without complications. Sensitivity analyses upheld the robustness of these findings, with no evidence of heterogeneity or pleiotropy. Additionally, 102 serum metabolites were found to exhibit statistically significant mediation effects on cataract risk, with four (13-HODE + 9-HODE, 2-naphthol sulfate, docosadienoate (22:2n6), and X-12906) showing significant mediation effects. Specifically, 13-HODE + 9-HODE had a protective effect, while the other three metabolites were linked to an increased cataract risk. This study provides strong evidence of a causal link between T1D and cataracts, highlighting the mediating role of specific serum metabolites. These findings underscore the importance of early detection and management of cataracts in patients with T1D and suggest potential therapeutic targets for mitigating cataract risk. Further research should focus on replicating these findings in diverse populations and exploring the underlying metabolic pathways in greater detail.

Serum metabolite profiles of thyroid autoimmunity patients in early pregnancy.

Research on serum metabolite profiles in thyroid autoimmunity (TAI) patients during early pregnancy is currently limited. The current study aimed to identify differential serum metabolites and assess the relationship between pregnancy outcomes and metabolic abnormalities in individuals with TAI. This research included 26 pregnant women with TAI and 30 healthy controls (HC). We employed a liquid chromatograph mass spectrometer (LC-MS) to analyze changes between the two groups. Newborns in the TAI patients had lower birth weights than those in the control group (P = 0.007). We identified 92 differential metabolites (including 50 upregulated and 42 downregulated) belonging to amino acids, fatty acyls, glycerophosphocholines, steroid and other categories and four significantly enrichment Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including taurine and hypotaurine metabolism, citrate cycle (TCA cycle), glyoxylate and dicarboxylate metabolism and 2-oxocarboxylic acid metabolism. We further identified 15 characteristic metabolites (6-Methylquinoline, D-erythrose 4-phosphate, 4-Hydroxyisoleucine, phosphatidylcholine (PC)(16:2e/16:0), N3,N4-Dimethyl-L-arginine, N-desmethyltramadol, 3-Methoxybenzaldehyde, sphingomyelin (SM)(d14:3/28:2), gamma-Glutamylleucine, NSI-189, 3-(1-cyano-1,2-dihydroisoquinolin-2-yl)-3-oxopropyl propionate, lysophosphatidylinositol (LPI) 16:0, cis-Aconitic acid, polyamide (PA)(18:1/18:2) and fatty acyl esters of hydroxy fatty acid (FAHFA)(17:0/18:0)) using least absolute shrinkage and selection operator (LASSO) regression. Correlation analyses revealed that 6-Methylquinoline, D-erythrose 4-phosphate, gamma-Glutamylleucine, and LPI 16:0 exhibited a positive correlation with anemia before delivery, while 3-(1-cyano-1,2-dihydroisoquinolin-2-yl)-3-oxopropyl propionate had a negative correlation. LPI 16:0 displayed a positive correlation with uric acid (UA) during both middle and late pregnancy, whereas 3-Methoxybenzaldehyde exhibited a negative correlation with UA in late pregnancy. Cis-Aconitic acid showed a positive correlation with fasting blood glucose (FBG) in middle pregnancy. Conversely, 6-Methylquinoline and 4-Hydroxyisoleucine had a negative correlation with birth weight. Thyroid autoantibodies were found to be associated with 14 metabolites identified using LASSO, with the exception of PA (18:1/18:2). Our findings provide new evidence supporting the early screening of serum metabolites and their potential for predicting adverse pregnancy outcomes in women with TAI.

Lactobacillus murinus alleviates insulin resistance via promoting L-citrulline synthesis.

The role of Lactobacillus murinus as a potential probiotic is being explored. Our objectives were to explore the effects of Lactobacillus murinus on insulin resistance and the underlying mechanism. Insulin resistance animal models were applied to study the effect of L. murinus and the underlying mechanism by six weeks of treatment. Metformin was administered in vitro to analyze the growth and metabolites of L. murinus. Serum metabolites were further analyzed after L. murinus administration. The effect of L-citrulline and the underlying mechanism in alleviating insulin resistance were evaluated. L. murinus not only reduced body weight gain and postprandial blood glucose (PBG) but improved impaired glucose tolerance (IGT) and insulin resistance. Moreover, L. murinus inhibited the secretion of pro-inflammatory factors (IL-1β, IL-6 and TNF-α) while promoted the secretion of anti-inflammatory factor (IL-10). Further, L. murinus promoted the expression of carnitine palmitoyl transferase 1 (CPT1) while inhibited phosphoenolpyruvate carboxykinase (PCK) and glucose-6-phosphatase (G6Pase). A total of 147 metabolites of L. murinus were identified, in which the content of L-citrulline increased to 7.94 times after metformin regulation. Further, the serum concentration of L-citrulline significantly increased after L. murinus administration. Similarly, L-citrulline reduced body weight gain and PBG, improved IGT and insulin resistance. Additionally, L-citrulline improved inflammation, promoted CPT1 while inhibited PCK and G6Pase. L. murinus mediated by L-citrulline alleviated insulin resistance via promoting fatty acid oxidation and inhibiting gluconeogenesis, suggesting that supplementation of L. murinus could be a potential therapeutic approach for type 2 diabetes related to insulin resistance.

Characteristic alterations of gut microbiota and serum metabolites in patients with chronic tinnitus: a multi-omics analysis.

Chronic tinnitus is a central nervous system disorder. Currently, the effects of gut microbiota on tinnitus remain unexplored. To explore the connection between gut microbiota and tinnitus, we conducted 16S rRNA sequencing of fecal microbiota and serum metabolomic analysis in a cohort of 70 patients with tinnitus and 30 healthy volunteers. We used the weighted gene co-expression network method to analyze the relationship between the gut microbiota and the serum metabolites. The random forest technique was utilized to select metabolites and gut taxa to construct predictive models. A pronounced gut dysbiosis in the tinnitus group, characterized by reduced bacterial diversity, an increased Firmicutes/Bacteroidetes ratio, and some opportunistic bacteria including Aeromonas and Acinetobacter were enriched. In contrast, some beneficial gut probiotics decreased, including Lactobacillales and Lactobacillaceae. In serum metabolomic analysis, serum metabolic disturbances in tinnitus patients and these differential metabolites were enriched in pathways of neuroinflammation, neurotransmitter activity, and synaptic function. The predictive models exhibited great diagnostic performance, achieving 0.94 (95% CI: 0.85-0.98) and 0.96 (95% CI: 0.86-0.99) in the test set. Our study suggests that changes in gut microbiota could potentially influence the occurrence and chronicity of tinnitus, and exert regulatory effects through changes in serum metabolites. Overall, this research provides new perceptions into the potential role of gut microbiota and serum metabolite in the pathogenesis of tinnitus, and proposes the "gut-brain-ear" concept as a pathomechanism underlying tinnitus, with significant clinical diagnostic implications and therapeutic potential.IMPORTANCETinnitus affects millions of people worldwide. Severe cases may lead to sleep disorders, anxiety, and depression, subsequently impacting patients' lives and increasing societal healthcare expenditures. However, tinnitus mechanisms are poorly understood, and effective therapeutic interventions are currently lacking. We discovered the gut microbiota and serum metabolomics changes in patients with tinnitus, and provided the potential pathological mechanisms of dysregulated gut flora in chronic tinnitus. We proposed the innovative concept of the "gut-brain-ear axis," which underscores the exploration of gut microbiota impact on susceptibility to chronic tinnitus through serum metabolic profile modulation. We also reveal novel biomarkers associated with chronic tinnitus, offering a new conceptual framework for further investigations into the susceptibility of patients, potential treatment targets for tinnitus, and assessing patient prognosis. Subsequently, gut microbiota and serum metabolites can be used as molecular markers to assess the susceptibility and prognosis of tinnitus.Furthermore, fecal transplantation may be used to treat tinnitus.

Breast cancer metastasis progression is associated with elevated activity of kynurenine monooxygenase and kynureninase.

Metastasis remains the major cause of death in breast cancer (BrCa) and lacks specific treatment strategies. The kynurenine pathway (KP) has been suggested as a key mechanism facilitating progression of BrCa. While KP activity has been explored in primary BrCa, its role in metastasis remains unclear. To better understand this, we examined changes in the KP of BrCa with no metastasis compared to BCa that produced local or distant metastases. Given that the cancer cell secretome plays a role in metastasis, we also investigated the relationship between changes in KP activity and serum proteins of patients with local or distant metastases. To investigate changes in the KP in BrCa, with and without metastasis, we quantified KP metabolites in blood sera collected from patients with stage 1 BrCa (n = 34), BrCa with local metastases (n = 46), BrCa with distant metastases (n = 20) and healthy controls (n = 39). The serum protein profile of the BrCa patients with local or distant metastasis was determined before correlation analyses were carried out to examine the relationship between changes in the KP and cancer serum proteins using SPSS. We found that the KP was elevated in BrCa patients with local and distant metastasis compared to healthy controls and stage 1 BrCa patients. The activity of kynurenine monooxygenase (KMO) and kynureninase (KYNU) A was positively associated with disease stage and was higher compared to healthy controls. Proteome analysis in patients with local or distant metastasis revealed the dysregulation of 14 proteins, 9 of which were up-regulated and 5 down-regulated at the distant metastasis stage. Importantly, three of these proteins have not been previously linked to BrCa metastasis. In the correlation studies between the KP profile, cancer serum proteins and metastasis status, KYNU A had the greatest number of significant associations with cancer serum protein, followed by KMO. Our findings reveal that the KP was regulated differently at various stages of BrCa and was more dysregulated in patients with local or distant metastasis. These KP activity changes showed a significant association with cancer serum proteins in BrCa patients with local or distant metastasis, highlighting the potential role of KP in BrCa metastasis.

Modulation of Serum Metabolic Profiles by Bifidobacterium breve BBr60 in Obesity: A Randomized Controlled Trial.

Obesity, a prevalent metabolic disorder in youth, leads to complications and economic strain. Gut dysbiosis significantly contributes to obesity and metabolic issues. Bifidobacterium breve, a probiotic strain, may help regulate gut dysbiosis and benefit obese individuals. However, more research is needed on its effect on serum metabolism. A total of 75 overweight or obese young adults (aged 19-45) participated in the current study, and were randomly divided into probiotic and placebo groups using a random number table. Both groups received dietary guidance and underwent twelve weeks of intervention with either oral Bifidobacterium breve BBr60 (BBr60) or a placebo. After the intervention, collection and analysis of fasting serum samples were conducted using mass spectrometry coupled with liquid chromatography. Analyses of associations were conducted in order to determine the correlations between key serum metabolites and clinical obesity indicators, aiming to understand the influence of BBr60. Due to 10 participants dropping out for personal reasons, the study included 32 and 33 participants in the placebo and the BBr60 groups, respectively. The BBr60 intervention significantly regulated 134 serum metabolites and influenced crucial metabolic pathways in obesity management (p < 0.05), including ascorbate and aldarate metabolism for oxidative stress reduction, cholesterol metabolism for lipid regulation, parathyroid hormone synthesis, secretion and action for the endocrine system, oxidative phosphorylation for enhanced energy efficiency, and glycolysis/gluconeogenesis for glucose metabolism. Analysis showed a positive relationship between fasting blood glucose (FBG), aspartate aminotransferase (AST), total protein (TP), and the content of 5-Methyl DL-glutamate (p < 0.05). Similarly, body mass index (BMI), weight, and body fat percentage (BFP) were positively linked to serum metabolites (1-Hydroxycyclohexyl) acetic acid, and 5-Oxooctanoic acid (p < 0.05). Significant associations of AST levels with key serum metabolites in cholesterol metabolism pathways further suggest BBr60's potential to improve liver function and overall metabolic health in overweight or obese individuals. These findings support BBr60's effectiveness in modulating serum metabolic profiles and suggest it may improve liver function and BMI in overweight or obese individuals by regulating key serum metabolites.

Abstract C022: Exercise reduces pancreatic tumor in a gut microbiome dependent manner

Abstract Preclinical studies suggest that aerobic exercise influences the tumor microenvironment by normalizing vasculature and reducing immunosuppression in Pancreatic Ductal Adenocarcinoma (PDAC). Gut microbes can influence PDAC progression by modulating metabolic and immune pathways. However, a knowledge gap remains regarding the role of the gut microbiome in the anti-tumor effects of exercise. We hypothesized that the exercise-induced anti-tumor effect in PDAC is regulated by gut microbiome. We compared the effect of treadmill running on growth of orthotopic PDAC in C57BL/6 mice from Taconic Biosciences (Tac) and Jackson Laboratories (Jax), which have different microbiomes. Tumor-bearing mice performed treadmill exercise (ex, 12 meters/minute (m/min) for 45 minutes (min) daily) or were non-exercised controls (no-ex). Exercise reduced tumor weight compared to no-ex controls in Jax (no-ex, 0.72±0.05 grams (g); ex, 0.54±0.04g; p=0.04) but not in Tac mice (no-ex, 0.72±0.05g; ex, 0.78±0.05g; p=0.47). Interestingly, in Tac mice treated with antibiotics (ATBx) ad libitum, treadmill exercise reduced tumor growth (no-ex, 0.74±0.04 g; ex, 0.53±0.03g; p= 0.006). Taken together, this data indicates that the anti-tumor effect of exercise is affected by gut microbiome. We considered potential mechanisms by which exercise suppresses tumor growth. Tumor infiltrating immune cells were measured by flow cytometry and immunohistochemistry. No significant differences in the tumor infiltrating immune cells were observed between no-ex and ex mice from Tac or Jax, regardless of ATBx, indicating that gut microbiome mediated anti-tumor effect is independent of immune pathways. Previous studies have demonstrated that exercise reduces tumor growth in an intensity dependent manner. Therefore, to determine exercise intensity as percentage of Peak Velocity (VPeak), exercise capacity (ExCap) test was performed. VPeak (m/min), time to exhaustion (min), and distance to exhaustion (m) were used as indicators for treadmill ExCap. Treadmill ExCap was significantly lower in tumor bearing Tac mice (24.86±3.55m/min, 12.56±1.79min, 217.17±31.02m) compared to Jax mice (30.50±3.81m/min; 16.58±2.07min; 320.15±40.02m; p=0.01). However, ATBx treatment did not change the treadmill ExCap in the Tac mice (25.50±3.19m/min; 12.62±1.58min; 209.26±26.16m; p=0.97) despite significantly changing the effect of exercise on tumor growth, indicating that ExCap may not regulate differences observed in the tumor weight. Overall, these results indicate that gut microbiome regulates anti-tumor effects of exercise, that are independent of tumor infiltrating immune cells or exercise intensity. Analysis of serum and tumor metabolites, 16s rRNAseq to evaluate microbial differences, and bulk RNAseq on tumors, is underway with the goal of identifying microbial-derived metabolites which mediate the anti-tumor effect of exercise. Understanding how the gut microbiome mediates the efficacy of exercise to suppress tumor growth will be critical for maximizing the benefits of exercise for patients with PDAC. Citation Format: Sumedha Pareek, Vidhi Chandra, Le Li, Hetal Patel, Truong Lam, Olivereen LeRoux, Haoyue Liu, Jonghae Lee, Florencia McAllister, Keri Schadler. Exercise reduces pancreatic tumor in a gut microbiome dependent manner [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C022.

Banxia Baizhu Tianma Decoction alleviates pentylenetetrazol-induced epileptic seizures in rats by preventing neuronal cell damage and apoptosis and altering serum and urine metabolic profiles

Ethnopharmacological relevanceEpilepsy (EP) is one of the most prevalent chronic neurological disorders in children, characterised by a prolonged course and a propensity for recurrence. Banxia Baizhu Tianma Decoction (BBTD), a traditional Chinese medicine formula, is commonly employed in the clinical management of EP and has demonstrated satisfactory therapeutic effects. Aim of the studyThis study aimed to evaluate the anti-epileptic effects of BBTD and to explore its molecular mechanisms. Materials and methodsEP rat model was induced by pentylenetetrazol (PTZ) and treated with BBTD. Parameters such as seizure grade and duration were recorded to evaluate the improvement of BBTD on epileptic behavior. Nissl staining was used to observe the pathological changes in the cerebral motor cortex. The expression levels of the Bax and Bcl-2 in the motor cortex were measured by western blot analysis to assess neuronal damage and apoptosis. The therapeutic action of BBTD was evaluated by examining the levels of neurotransmitters γ-aminobutyric acid (GABA) and glutamate (Glu) in the brain tissue of EP rats, along with assessments of neuronal damage and apoptosis. Non-targeted metabolomics techniques were employed to conduct a comprehensive analysis of serum and urine metabolites, and network analysis of metabolite-related targets was performed to enhance understanding of the anti-epileptic effects and mechanisms of BBTD. ResultsAfter BBTD treatment, the EP model rats exhibited reduced seizure severity and shortened seizure duration. Moreover, BBTD mitigated PTZ-induced neuronal damage, as evidenced by a significant increase in the number of Nissl bodies in the motor cortex following treatment. At the same time, BBTD inhibited neuronal apoptosis, as demonstrated by the up-regulation of the anti-apoptotic protein Bcl-2 and down-regulation of the pro-apoptotic protein Bax in the brain tissue of treated rats. In addition, BBTD reversed the decreased levels of GABA and the increased levels of Glu in the brain tissue of the model group. Metabolomics analyses suggested that BBTD treatment for EP may be closely associated with alterations in urinary metabolites related to vitamin B6 and pyrimidine metabolism, as well as serum metabolites involved in purine metabolism, glycerophospholipid metabolism and vitamin B6 metabolism. Finally, network analysis of metabolite targets indicated that dopamine and alpha-linolenic acid metabolites may play significant roles in the therapeutic effects of BBTD on EP. ConclusionBBTD demonstrated anti-epileptic effects in PTZ-induced seizure rats by regulating neurotransmitter balance, reducing neuronal damage and inhibiting apoptosis, suggesting its potential for the development of novel AEDs. This is the first time that UHPLC-MS-based urine and serum metabolomics have been used to elucidate the anti-epileptic mechanism of BBTD, providing insights into the underlying mechanisms of BBTD's action.

The pesticide paradox: Metabolomics insights into N-Methyl-2-pyrrolidone (NMP) exposure as a culprit of infant undernourishment

N-methyl-2-pyrrolidone (NMP) is widely used in various industrial applications as a solvent, due to its effectiveness. However, its excessive use might end up with harmful effects on human health. In this investigation, we explored the association between infant serum metabolites and undernourishment among infants born to mothers exposed to pesticides from pregnancy to 6 months of breastfeeding. Using an untargeted metabolomics approach, we analyzed 171 serum samples from infants aged 3-6 months, comprising 149 cases of undernutrition (WHZ < − 2) and 22 controls (WHZ > 0). After performing statistical analysis, 9 metabolites exhibited significance at a p-value of < 0.05. Notably, one of these metabolites, N-methyl-2-pyrrolidone (NMP) a well-known pesticide adjuvant, is found to be significantly elevated among undernourished infants. NMP is recognized for its potential toxic effects and adverse health consequences. This is the first study in which its effect on humans is observed, as previous studies were conducted on animal models. Moreover, two essential fatty acids, stearic acid and heneicosanoic acid, are found to be lower in undernourished infants. This finding raises questions about the mothers' diet, in addition to pesticide exposure, particularly since all infants were exclusively breastfed. Further studies are needed to understand the long-term impact of pesticide exposure on pregnant mothers as well as the aftermath on their infants. Overall our findings highlight NMP's industrial utility and its detrimental health consequences potentially creating a paradox, highlighting the conflicting interests between industrial and health sectors regarding the same chemical.