Association between plasma trimethylamine N-oxide and coronary heart disease: new insights on sex and age differences.

Aim: Elevated plasma trimethylamine N-oxide (TMAO) is related to atherosclerosis. Whether the relationship of TMAO and coronary heart disease (CHD) is influenced by sex or age is uncertain. We aim to explore the sex and age differences in the relationship between plasma TMAO and CHD risk and severity. Methods: A case-control study was conducted in patients undergoing elective coronary angiography. Matched by sex, age (±2 years), and operation date (±180 days), a total of 429 CHD case-control pairs were included. Plasma TMAO was quantified using liquid chromatography-tandem mass spectrometry. Logistic regression analyses were performed to evaluate the association between plasma TMAO and CHD risk and severity. Results: The overall median (interquartile range) plasma TMAO level was 0.11 (0.06-0.18) µg/ml. After stratification by sex and age, and adjustment for common CHD risk factors, the association between TMAO and CHD risk was significant in the older (≥65 years) male subgroup [odds ratios (OR) = 1.57, 95% confidence interval (CI): 1.09-2.28, P = 0.016], but not in other sex-age subgroups (all P > 0.05). The relationship of plasma TMAO and CHD risk was modified by age (adjusted P interaction = 0.001) in male individuals. Plasma TMAO was also associated with a higher risk of multi-vessel disease in male patients with CHD (OR = 1.65, 95% CI: 1.18-2.32, P = 0.004), but not in females. Conclusions: Plasma TMAO is significantly positively associated with the risk and severity of CHD in Chinese men. Age has an interactive effect on the relationship between plasma TMAO and CHD risk in men. Our findings warrant further investigation.

Flavonoids, gut microbiota and cardiovascular disease: Dynamics and interplay.

Cardiovascular disease (CVD) remains the leading cause of global morbidity and mortality. Extensive efforts have been invested to explicate mechanisms implicated in the onset and progression of CVD. Besides the usual suspects as risk factors (obesity, diabetes, and others), the gut microbiome has emerged as a prominent and essential factor in the pathogenesis of CVD. With its endocrine-like effects, the microbiome modulates many physiologic processes. As such, it is not surprising that dysbiosis-by generating metabolites, inciting inflammation, and altering secondary bile acid signaling- could predispose to or aggravate CVD. Nevertheless, various natural and synthetic compounds have been shown to modulate the microbiome. Prime among these molecules are flavonoids, which are natural polyphenols mainly present in fruits and vegetables. Accumulating evidence supports the potential of flavonoids in attenuating the development of CVD. The ascribed mechanisms of these compounds appear to involve mitigation of inflammation, alteration of the microbiome composition, enhancement of barrier integrity, induction of reverse cholesterol transport, and activation of farnesoid X receptor signaling. In this review, we critically appraise the methods by which the gut microbiome, despite being essential to the human body, predisposes to CVD. Moreover, we dissect the mechanisms and pathways underlying the cardioprotective effects of flavonoids.

Microbiota and detrimental protein derived metabolites in colorectal cancer.

Colorectal cancer (CRC) is the third leading cancer in incidence and the second leading cancer in mortality worldwide. There is growing scientific evidence to support the crucial role of the gut microbiota in the development of CRC. The gut microbiota is the complex community of microorganisms that inhabit the host gut in a symbiotic relationship. Diet plays a crucial role in modulating the risk of CRC, with a high intake of red and processed meat being a risk factor for the development of CRC. The production of metabolites derived from protein fermentation by the gut microbiota is considered a crucial element in the interaction between red and processed meat consumption and the development of CRC. This paper examines several metabolites derived from the bacterial fermentation of proteins associated with an increased risk of CRC. These metabolites include ammonia, polyamines, trimethylamine N-oxide (TMAO), N-nitroso compounds (NOC), hydrogen sulphide (H2S), phenolic compounds (p-cresol) and indole compounds (indolimines). These compounds are depicted and reviewed for their association with CRC risk, possible mechanisms promoting carcinogenesis and their relationship with the gut microbiota. Additionally, this paper analyses the evidence related to the role of red and processed meat intake and CRC risk and the factors and pathways involved in bacterial proteolytic fermentation in the large intestine.

Bie Jia Jian pill ameliorates BDL-induced cholestatic hepatic fibrosis in rats by regulating intestinal microbial composition and TMAO-mediated PI3K/AKT signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: As a compound of traditional Chinese medicine (TCM), Bie Jia Jian pill (BJJP) is extensively used to treat the clinical chronic liver disease. Nevertheless, the specific mechanism through which BJJP affects hepatic fibrosis (HF) remains unknown. AIM OF THE STUDY: To explore the role and potential mechanism of BJJP involved in treating HF. MATERIALS AND METHODS: HF model of Sprague-Dawley (SD) rats was induced by a bile duct ligation (BDL). The function of BJJP involved in the intestinal microbiota (IM) and its metabolites in BDL-induced HF rats were explored through the 16S rRNA sequencing and untargeted metabolomics technologies. Network pharmacology was used to forecast mechanism underlying BJJP's anti-HF effects, which were validated in BDL-induced rats and trimethylamine N-oxide (TMAO)-induced LX-2 and HSC-T6 cells. RESULTS: BJJP effectively ameliorated pathological liver damage, inflammation, and fibrosis of the BDL-induced HF rats. BJJP regulated IM diversity and composition and interfered with trimethylamine (TMA)-flavin monooxygenase 3 (FMO3)-TMAO process. In vitro, BJJP significantly inhibited the TMAO-induced activation of hepatic stellate cells (HSCs) (rat HSC cell line, HSC-T6; human HSC cell line, LX-2). Network pharmacology results demonstrated that PI3K/AKT signal pathway is crucially involved in BJJP treatment of HF. Further research revealed that BJJP inhibited the PI3K/AKT signal pathway in BDL-induced HF rats. Moreover, TMAO activated the PI3K/AKT pathway, whereas BJJP suppressed TMAO-induced activation. Subsequent intervention with 740Y-P (the PI3K agonist) successfully neutralized the repression effect on PI3K/AKT signal pathway by BJJP. CONCLUSION: These results clearly show that BJJP attenuates HF by regulating the IM, as well as inhibiting PI3K/AKT pathway mediated by TMAO.

Integrated metabolomics and network pharmacology to reveal the mechanisms of Shexiang Baoxin pill against atherosclerosis.

BACKGROUND: Atherosclerosis is a disease marked by the development of lipid lesions within the endothelium and continues to be a prominent contributor to global mortality. Shexiang Baoxin pill (SBP) has been employed in the management of numerous cardiovascular diseases, but the complex mechanisms by which it operates remain obscure. This research was conducted to determine the potential impact of SBP on atherosclerosis and the underlying regulatory mechanism involved. METHOD: Network pharmacology was utilized to predict the key drug-disease targets, and a nontargeted metabolomic assay was applied to identify the key metabolites and metabolic pathways. A mouse atherosclerosis model was constructed to clarify the protective effect of SBP on atherosclerosis, and in vivo and in vitro tests were performed to verify the analysis results and clarify the mechanism through which SBP affects atherosclerosis. RESULTS: The results show that SBP can exert a protective effect in vivo by decreasing lipid levels, plaque formation and endothelial damage. Network pharmacology and metabolomics revealed that MAPK3, AKT1 and STAT3 were the hub targets and that trimethylamine n-oxide (TMAO) was the pivotal metabolite. Due to the atherogenic effect of TMAO, the corresponding protective effect of SBP was investigated in vitro. SBP inhibited TMAO-induced endothelial cell apoptosis and oxidative stress and counteracted the upregulation of MAPK3, AKT1, and STAT3 expression. Molecular docking and enzymatic inhibition suggested that the active components of SBP could bind stably to key target proteins. CONCLUSION: Taken together, based on the integrated metabolomics and network pharmacology, our findings suggest that SBP may be implicated in TMAO-induced atherosclerosis by affecting endothelial function and bile acid synthesis. We observed that SBP may ameliorate atherosclerosis by regulating TMAO levels through multiple pathways, which may provide a novel direction and insight for SBP involved in cardiovascular protection by mediating the gut-heart axis.

Elevated Circulating Levels of Gut Microbe-Derived Trimethylamine N-Oxide Are Associated with Systemic Sclerosis.

Background/Objectives: Alterations in fecal microbial communities in patients with systemic sclerosis (SSc) are common, but the clinical significance of this observation is poorly understood. Gut microbial production of trimethylamine (TMA), and its conversion by the host to trimethylamine N-oxide (TMAO), has clinical and mechanistic links to cardiovascular and renal diseases. Direct provision of TMAO has been shown to promote fibrosis and vascular injury, hallmarks of SSc. We sought to determine levels of TMAO and related metabolites in SSc patients and investigate associations between the metabolite levels with disease features. Methods: This is an observational case:control study. Adults with SSc (n = 200) and non-SSc controls (n = 400) were matched for age, sex, indices of renal function, diabetes mellitus, and cardiovascular disease. Serum TMAO, choline, betaine, carnitine, γ-butyrobetaine, and crotonobetaine were measured using stable isotope dilution liquid chromatography tandem mass spectrometry. Results: Median TMAO concentration was higher (p = 0.020) in SSc patients (3.31 [interquartile range 2.18, 5.23] µM) relative to controls (2.85 [IQR 1.88, 4.54] µM). TMAO was highest among obese and male SSc participants compared to all other groups. Following adjustment for sex, BMI, age, race, and eGFR in a quantile regression model, elevated TMAO levels remained associated with SSc at each quantile of TMAO. Conclusions: Patients with SSc have increased circulating levels of TMAO independent of comorbidities including age, sex, renal function, diabetes mellitus, and cardiovascular disease. As a potentially modifiable factor, further studies examining the link between TMAO and SSc disease severity and course are warranted.

Low-Molecular-Weight Compounds Produced by the Intestinal Microbiota and Cardiovascular Disease.

Cardiovascular disease is the main cause of mortality in industrialized countries, with over 500 million people affected worldwide. In this work, the roles of low-molecular-weight metabolites originating from the gut microbiome, such as short-chain fatty acids, hydrogen sulfide, trimethylamine, phenylacetic acid, secondary bile acids, indoles, different gases, neurotransmitters, vitamins, and complex lipids, are discussed in relation to their CVD-promoting or preventing activities. Molecules of mixed microbial and human hepatic origin, such as trimethylamine N-oxide and phenylacetylglutamine, are also presented. Finally, dietary agents with cardioprotective effects, such as probiotics, prebiotics, mono- and poly-unsaturated fatty acids, carotenoids, and polyphenols, are also discussed. A special emphasis is given to their gut microbiota-modulating properties.

Protective Role of (-)-Epicatechin on Trimethylamine-N-Oxide (TMAO)-Induced Cardiac Hypertrophy via SP1/SIRT1/SUMO1 Signaling Pathway.

(-)-Epicatechin (EPI) is beneficial for cardiovascular health. Trimethylamine N-oxide (TMAO), a gut microbe-derived food metabolite, is strongly associated with the risk of cardiovascular diseases. However, the effects and underlying mechanisms of EPI on TMAO-induced cardiac hypertrophy remain unclear. This study aimed to determine whether EPI inhibits TMAO-induced cardiac hypertrophy. Plasma levels of TMAO in control participants and patients with cardiac hypertrophy were measured and analyzed. Male C57BL/6 mice were randomly divided into control group, TMAO group, EPI group and TMAO + EPI group. According to the groups assignments, mice received intraperitoneal (i.p.) injection of normal saline or i.p. injection of TMAO (150 mg/kg/day) for 14 days. The EPI group was given intragastric (i.g.) administration of EPI alone (1 mg/kg/day) for 21 days, and TMAO + EPI group received i.g. administration of EPI for 7 days before starting i.p. injection of TMAO, continuing until the end of the TMAO treatment. Histological analyses of the mice's hearts was accessed by H&E and Masson staining. In vitro, H9c2 cells were induced to hypertrophy by TMAO (10 µM) for 24 h and were pre-treated with or without EPI (10 µM) for 1 h. Protein level of cardiac hypertrophy markers and Sp1/SIRT1/SUMO1 pathway were determined by western blot. The plasma level of TMAO was 2.66 ± 1.59 µmol/L in patients with cardiac hypertrophy and 0.62 ± 0.30 µmol/L in control participants. EPI attenuated TMAO-induced hypertrophy in H9c2 cells. In vivo, TMAO induced cardiac hypertrophy and impaired the cardiac function of mice. Pathological staining showed that TMAO induced cardiac hypertrophy and collagen deposition in mice. EPI treatment improved the cardiac function, inhibited the myocardial hypertrophy induced by TMAO. EPI significantly attenuated the TMAO-induced upregulation of ANP and BNP and the downregulation of SP1, SIRT1 and SUMO1 in vivo and in vitro. EPI may suppress TMAO-induced cardiac hypertrophy by activating the Sp1/SIRT1/SUMO1 signaling pathway.

Trimethylamine N-Oxide Aggravates Neuro-Inflammation via lncRNA Fendrr/miR-145-5p/PXN Axis in Vascular Dementia Rats.

Purpose: Vascular dementia (VaD) is the second most common dementia in the world. An increasing number of studies have demonstrated the important role of long non-coding RNAs (lncRNAs) in VaD. Our previous investigation demonstrated that Trimethylamine-N-oxide (TMAO) exacerbates cognitive impairment and neuropathological alterations in VaD rats. Thus, we hypothesized that TMAO could play an injury role in VaD by regulating lncRNAs. Materials and Methods: The rats using the bilateral common carotid artery (2VO) model were administered TMAO (120 mg/kg) for 8 consecutive weeks, 4 weeks preoperatively and 4 weeks postoperatively. High-throughput sequencing was conducted to investigate the effects of TMAO treatment on lncRNA expression in rat hippocampus and bioinformatics analysis was performed to identify potential downstream targets. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the levels of lncRNA fetal-lethal noncoding developmental regulatory RNA (Fendrr), miR-145-5p, and paxillin (PXN). Learning and spatial memory capacities were measured, as well as inflammatory factors. Nissl staining was used to observe neuronal injury in the CA1 area of the hippocampus. Furthermore, we used the Fendrr loss-of-function assay, miR-145-5p gain-of-function assays and PXN loss-of-function assay to explore the mechanisms by which TMAO acts on VaD. Results: TMAO administration upregulated lncRNA Fendrr expression in the rat hippocampus, while the damaging effects of TMAO were counteracted after knockdown of Fendrr. Fendrr exhibits highly expressed in 2VO rats and sponged miR-145-5p, which targets PXN. Silencing of Fendrr or PXN, or promotion of miR-145-5p improved neurological function injury, reduced neuronal damage, as well as repressed inflammation response. Inhibition of miR-145-5p abrogated up Fendrr knockdown mediated influence on 2VO rats. Conclusion: The results of this study indicated that TMAO inhibits the miR-145-5p/PXN axis by increasing the Fendrr expression, thus exacerbating the development of VaD.

Gut Microbiota and Metabolic Alterations Associated with Heart Failure and Coronary Artery Disease.

This study investigates the role of gut microbiota in cardiovascular diseases, with an additional focus on pro-atherogenic metabolites. We use advanced network analysis and machine learning techniques to identify key microbial features linked to coronary artery disease (CAD) and heart failure with reduced ejection fraction (HFrEF). This cross-sectional study included 189 participants divided into three groups: coronary artery disease (n = 93), heart failure with reduced ejection fraction (n = 43), and controls (n = 53). Assessments included physical exams, echocardiography, dietary surveys, blood analysis, and fecal analysis. Gut microbiota composition was analyzed using next-generation sequencing (NGS) and quantitative polymerase chain reaction (qPCR). Statistical analysis methods for testing hypotheses and correlations, alpha and beta-diversity analyses, co-occurrence networks, and machine learning were conducted using Python libraries or R packages with multiple comparisons corrected using the Benjamini-Hochberg procedure. Significant gut microbiota alterations were observed, with higher Bacillota/Bacteroidota ratios in CAD and HFrEF groups compared to controls (p < 0.001). Significant differences were observed in α-diversity indices (Pielou, Chao1, Faith) between disease groups and controls (p < 0.001). ß-diversity analyses also revealed distinct microbial profiles (p = 0.0015). Interestingly, trimethylamine N-oxide (TMAO) levels were lower in CAD and HFrEF groups compared to controls (p < 0.05), while indoxyl sulfate (IS) levels were comparable between the study groups. Co-occurrence network analysis and machine learning identified key microbial features linked to these conditions, highlighting complex interactions within the gut microbiota associated with cardiovascular disease.

Dysbiosis and Regulation of Gut Microbiota in Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus is a serious metabolic disease having a high growth rate and becoming a global threat. An unhealthy lifestyle, food intake, and genetic susceptibility are the major factors responsible for this metabolic disorder. This disease results in hyperlipidemia, hyperglycemia, glucose intolerance, restricted insulin synthesis, and insulin resistance. Despite a variety of treatments currently available, cases of diabetes and resulting complications are on the rise. One promising approach to diabetes focuses on gut microflora and their associated metabolites. Gut microbiota has attracted widespread attention due to its crucial role in disease pathophysiology. This study explores the dysbiosis in the human gut microflora in Type 2 Diabetes Mellitus and how the gut microbiota influences metabolites related to T2DM. It also sheds light on early identification and targeted intervention for this. Understanding these mechanisms could potentially lead to more effective strategies for managing and preventing T2DM. The findings of our literature study are that gut microbiota can serve as biomarkers for early disease detection. Finally, we also highlight gut microecological therapeutic strategies focused on shaping the gut flora to emphasize the improvement of T2DM progression.

The association between trimethylamine N-oxide levels and coronary microvascular dysfunction and prognosis in patients with ST-elevation myocardial infarction.

BACKGROUND AND AIMS: Coronary microvascular dysfunction (CMD) is common after ST-elevation myocardial infarction (STEMI), leading to adverse clinical outcomes. However, its diagnosis remains difficult, and mechanisms elusive. This study explores the role of Trimethylamine N-oxide (TMAO), a gut microbiota metabolite, as a potential biomarker for diagnosing CMD in STEMI patients. METHODS: This prospective, observational study enrolled 210 STEMI patients with multivessel coronary artery disease who underwent primary percutaneous coronary intervention (PCI). TMAO levels were measured at baseline, 3 months, and 12 months post-PCI, whilst coronary physiology was assessed at 3 months. The primary endpoint was the incidence of CMD at 3 months, with the secondary endpoint being major adverse cardiovascular and cerebrovascular events (MACCE) at 12 months. An additional 59 consecutive patients were enrolled for validation. RESULTS: TMAO levels varied from baseline to 3 months, then stabilised. The areas under the ROC curve for baseline TMAO and TMAO at 3-month were 0.55 (95 % CI 0.46-0.64; p = 0.426), and 0.80 (95 % CI 0.73-0.87; p < 0.001), respectively. The optimal cut-off for TMAO at 3-month to diagnose CMD was 3.91, with similar sensitivity and specificity in the derivation and validation cohort. The incidence of MACCE was higher in patients with TMAO≥3.91 (41.4 % vs 10.7 %; p < 0.001). The addition of 3-month TMAO improved the diagnostic performance of traditional risk factors. CONCLUSION: TMAO is a robust biomarker for CMD and is significantly associated with the incidence of MACCE. TMAO has the potential in guiding clinical decision-making and suggests an interplay between gut microbiota and CMD.

Effect of Purified Resveratrol Butyrate Ester Monomers against Hypertension after Maternal High-Fructose Intake in Adult Offspring.

BACKGROUND: Offspring hypertension arising from adverse maternal conditions can be mitigated through dietary nutritional supplementation, including resveratrol. Previously, we identified derivatives of resveratrol butyrate ester (RBE), specifically 3,4'-di-O-butanoylresveratrol (ED2) and 3-O-butanoylresveratrol (ED4), demonstrating their superior antioxidant capabilities compared to RBE itself. This study sought to assess the protective impact of maternal supplementation with ED2 or ED4 on offspring hypertension in a rat model subjected to a high-fructose (HF) diet during pregnancy and lactation. METHODS: Female Sprague-Dawley rats were distributed into distinct dietary groups throughout pregnancy and lactation: (1) standard chow; (2) HF diet (60%); (3) HF diet supplemented with ED2 (25 mg/L); and (4) HF diet supplemented with ED4 (25 mg/L). Male offspring were euthanized at the age of 12 weeks. RESULTS: The maternal HF diet induced hypertension in the offspring, which was mitigated by perinatal supplementation with either ED2 or ED4. These protective effects were attributed to the antioxidant properties of ED2 and ED4, resulting in an increased availability of nitric oxide (NO). Additionally, supplementation with ED2 was connected to an increased abundance of Bifidobacterium and Clostridium genera, which was accompanied by a decrease in Angelakisella and Christensenella. On the other hand, ED4 supplementation shielded rat offspring from hypertension by elevating concentrations of short-chain fatty acids (SCFAs) and their receptors while reducing trimethylamine-N-oxide (TMAO) levels. CONCLUSIONS: These findings highlight the potential of purified RBE monomers, ED2 and ED4, as preventive measures against hypertension resulting from a maternal high-fructose diet. Further research is warranted to explore their clinical applications based on these promising results.

Gut microbiota metabolite trimethylamine N-oxide promoted NAFLD progression by exacerbating intestinal barrier disruption and intrahepatic cellular imbalance.

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide, with the gut microbiota and its metabolites are important regulators of its progression. Trimethylamine N-oxide (TMAO), a metabolite of the gut microbiota, has been closely associated with various metabolic diseases, but its relationship with NAFLD remains to be elucidated. In this study, we found that fecal TMAO levels correlated with NAFLD severity. Moreover, TMAO promoted lipid deposition in HepG2 fatty liver cells and exacerbated hepatic steatosis in NAFLD rats. In the colon, TMAO undermined the structure and function of the intestinal barrier at various levels, further activated the TLR4/MyD88/NF-κB pathway, and inhibited the WNT/ß-catenin pathway. In the liver, TMAO induced endothelial dysfunction with capillarization of liver sinusoidal endothelial cells, while modulating macrophage polarization. In conclusion, our study suggests that gut microbiota metabolite TMAO promotes NAFLD progression by impairing the gut and liver and that targeting TMAO could be an alternative therapeutic strategy for NAFLD.

Trimethylamine N-oxide promotes PERK-mediated endothelial-mesenchymal transition and apoptosis thereby aggravates atherosclerosis.

The endothelial-mesenchymal transition (EndMT) is involved in the development of atherosclerosis (AS) and is a key process in vascular endothelial injury. Oxidative stress, inflammation, and apoptosis are common causes of EndMT, and EndMT progression can further accelerate the development of AS. The metabolite trimethylamine N-oxide (TMAO) is produced by the gut microbiome and is implicated in the development of several diseases, including diabetes and chronic kidney disease. However, the impact of TMAO on transforming growth factor ß1(TGF-ß1)-induced EndMT remains unclear. We hypothesize that TMAO exacerbates plaque formation and cardiac function impairment by promoting EndMT. Herein, we showed that high serum TMAO levels caused plaque formation, cardiac function damage and haemodynamic changes in ApoE-/- mice. In vitro, TMAO upregulated mesenchymal markers and downregulated endothelial markers in HAECs. Furthermore, TMAO increased the migratory capacity of EndMT cells. Mechanistically, we found that PERK downregulation could alleviate TMAO-induced oxidative stress, EndMT, plaque formation and cardiac function damage. Further study showed that activated transcription factor 3 (ATF3), the downstream molecule of protein kinase RNA-like endoplasmic reticulum kinase (PERK), could bind with TGF-ß1/2 and affect EndMT. Overall, TMAO promotes EndMT, possibly through the PERK-eIF2α-ATF4-CHOP or the PERk-eIF2α-ATF3-TGF-ß signalling pathways.

Trimethylamine-N-oxide and 5-year mortality: the role of gut microbiota-generated metabolite from the CORE-Thailand cohort.

The gut microbiota metabolite trimethylamine-N-oxide (TMAO)-derived from dietary phosphatidylcholine-is mechanistically linked to cardiovascular disease (CVD) and increased cardiovascular risk. This study examined the relationship between fasting plasma TMAO levels and 5-year all-cause mortality in a cohort of patients at high risk of cardiovascular events (CORE-Thailand Registry). Of the 134 patients, 123 (92%) had established cardiovascular disease, and 11 (8%) had multiple risk factors. Fasting plasma TMAO levels were measured using nuclear magnetic resonance spectroscopy. Within this prospective cohort study, the median TMAO was 3.81 µM [interquartile range (IQR) 2.89-5.50 µM], with a mean age of 65 ± 11 years; 61% were men, and 39.6% had type II diabetes. Among 134 patients, 65 (49%) were identified as the high-TMAO group (≥ 3.8 µM), and 69 (51%) were identified as the low-TMAO group (< 3.8 µM). After a median follow-up of 58.8 months, the high-TMAO group was associated with a 2.88-fold increased mortality risk. Following adjustment for traditional risk factors, high-sensitivity cardiac troponin-T, estimated glomerular filtration rate, angiotensin-converting enzyme (ACEI), or angiotensin-receptor blocker (ARB) use, the high-TMAO group remained predictive of 5-year all-cause mortality risk (the high-TMAO vs. the low-TMAO group, adjusted hazard ratio 2.73, 95% CI 1.13-6.54; P = 0.025). Among Thai patients at high risk of cardiovascular events, increased plasma TMAO levels portended greater long-term mortality risk.

Potential Trimethylamine (TMA)-Producing Bacteria in patients with chronic kidney disease undergoing hemodialysis.

INTRODUCTION: Trimethylamine (TMA), produced by gut microbiota, is the precursor of trimethylamine-N-oxide (TMAO), a uremic toxin that accumulates in patients with chronic kidney disease (CKD). Elevated TMAO plasma levels are associated with cardiovascular complications and CKD progression. OBJECTIVE: To evaluate the association between gut microbiota composition and TMAO plasma levels in CKD patients undergoing hemodialysis (HD). METHODS: This is a cross-sectional study with 25 patients evaluated (60% female, 53 (18) years, body mass index (BMI) 25.8 (6.75) Kg/m2). They were divided into two groups according to their TMAO plasma levels: normal (≤ 7.4 µM) and high (> 7.4 µM). Uremic toxins such as indoxyl sulfate (IS), p-cresyl sulfate (pCS), and indol acetic acid (IAA) were measured with RP-HPLC, and TMAO plasma levels were quantified using LC-MS/MS. Fecal DNA was extracted with a commercial kit, PCR amplified the V4 region of the 16S rRNA gene, and short-read sequencing was performed on the Illumina platform. Dietary intake, anthropometric measurements, and inflammation markers were also evaluated. Nrf2, NF-κB, IL-1ß, and NLRP3 mRNA expressions were measured from peripheral blood mononuclear cells (PBMC) using quantitative real-time polymerase chain reaction (qPCR). RESULTS: There were significant positive correlations between TMAO and plasma levels of pCS, NLPR3 inflammasome mRNA expression, serum phosphorus levels, and negative correlations with dietary lipid intake. The group with TMAO > 7.4 µM showed an increase in the microbiome abundance of Saccharibacteria (genus incertae sedis), Colidextribacter, Dorea, and Staphylococci genera, and a decrease in abundance in the genera Lachnospira, Lactobacilli, and Victivallis. TMAO plasma level was positively correlated with the abundance of bacteria of the genera Colidextribacter and Helicobacter and was negatively correlated with Sphingomanos, Lachnospira, Streptomyces, and Bacillus genera. CONCLUSION: Saccharibacteria (genus incertae sedis), Colidextribacter, Dorea, and Staphylococci genera showed higher abundance in patients with high TMAO levels. In addition, we observed that elevated plasma TMAO levels are associated with inflammation markers, dietary lipid intake, and serum phosphorus levels in patients undergoing HD.

Trimethylamine N-oxide induces non-alcoholic fatty liver disease by activating the PERK.

Nonalcoholic fatty liver disease (NAFLD) is a liver disease causing different progressive pathological changes. Trimethylamine N-oxide (TMAO), a product of gut microbiota metabolism, is a specific agonist of the protein kinase R-like endoplasmic reticulum kinase (PERK) pathway, one of the endoplasmic reticulum stress (ERS) pathways. TMAO has been associated with the occurrence and development of NAFLD based on the results of previous studies, but whether the simple consumption of TMAO can directly induce NAFLD and its underlying mechanism remain unclear. To investigate this question, we constructed an animal model in which adult male zebrafish were fed a controlled diet containing 1 % or 3 % TMAO for 20 weeks. Eventually, we observed that TMAO caused lipid accumulation, inflammatory infiltration, liver injury and liver fibrosis in zebrafish livers; meanwhile, the PERK signaling pathway was activated in the zebrafish livers. This finding was further confirmed in HepG2 cells and hepatic stellate cells models. In conclusion, this study found that TMAO directly induced different pathological states of NAFLD in zebrafish liver, and the activation of PERK pathway is an important mechanism, which may provide crucial strategies for the diagnosis and treatment of NAFLD.

Exposure to prenatal excess or imbalanced micronutrients leads to long-term perturbations in one-carbon metabolism, trimethylamine-N-oxide and DNA methylation in Wistar rat offspring.

Prenatal multivitamins, including folic acid, are commonly consumed in excess, whereas choline, an essential nutrient and an important source of labile methyl groups, is underconsumed. Here, we characterized profiles of one-carbon metabolism and related pathways and patterns of DNA methylation in offspring exposed to excess or imbalanced micronutrients prenatally. Pregnant Wistar rats were fed either recommended 1× vitamins (RV), high 10× vitamins (HV), high 10× folic acid with recommended choline (HFolRC), or high 10× folic acid with no choline (HFolNC). Offspring were weaned to a high-fat diet for 12 weeks. Circulating metabolites were analyzed with a focus on the hypothalamus, an area known to be under epigenetic regulation. HV, HFolRC, and HFolNC males had higher body weight (BW) and lower plasma choline and methionine consistent with lower hypothalamic S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) and global DNA methylation compared with RV. HV and HFolNC females had higher BW and lower plasma 5-methyltetrahydrofolate and methionine consistent with lower hypothalamic global DNA methylation compared with RV. Plasma dimethylglycine (DMG) and methionine were higher as with hypothalamic SAM:SAH and global DNA methylation in HFolRC females without changes in BW compared with RV. Plasma trimethylamine and trimethylamine-N-oxide were higher in males but lower in females from HFolRC compared with RV. Network modeling revealed a link between the folate-dependent pathway and SAH, with most connections through DMG. Final BW was negatively correlated with choline, DMG, and global DNA methylation. In conclusion, prenatal intake of excess or imbalanced micronutrients induces distinct metabolic and epigenetic perturbations in offspring that reflect long-term nutritional programming of health.

Trimethylamine N-oxide promotes the proliferation and migration of hepatocellular carcinoma cell through the MAPK pathway.

Trimethylamine-n-oxide (TMAO) is a metabolite of intestinal flora following the consumption of phosphatidylcholine-rich foods. Clinical cohort studies have shown that plasma TMAO may be a risk factor for cancer development, including hepatocellular carcinoma (HCC), but fundamental research data supporting this hypothesis are lacking. In this study, HCC cells were treated with TMAO in vivo and in vitro to evaluate the effect on some indicators related to the malignancy degree of HCC, and the relevant molecular mechanisms were explored. In vitro, TMAO promoted the proliferation and migration of HCC cells and significantly upregulated the expression of proteins related to epithelial-mesenchymal transformation (EMT). In vivo, after HCC cells were inoculated subcutaneously in nude mice given water containing TMAO, the tumors grew faster and larger than those in the mice given ordinary water. The immunohistochemistry analysis showed that proliferation, migration and EMT-related proteins in the tumor tissues were significantly upregulated by TMAO. Furthermore, TMAO obviously enhanced the phosphorylation of MAPK signaling molecules in vivo and in vitro. In conclusion, TMAO promotes the proliferation, migration and EMT of HCC cells by activating the MAPK pathway.