Concentrations Of TMAO Research Articles

TMAO is involved in kidney-yang deficiency syndrome diarrhea by mediating the “gut-kidney axis”

BackgroundTrimethylamine-N-oxide (TMAO) is a harmful metabolite dependent on the intestinal microbiota and excreted through the kidneys. According to numerous investigations, rich circulation concentrations of TMAO have been linked to kidney and gastrointestinal disorders. Through the “gut-kidney axis” mediated by TMAO, this research attempted to clarify the microbiological causes of kidney-yang deficiency syndrome diarrhea. MethodsAdenine and Folium Sennae were used to create a mouse model of kidney-yang deficiency syndrome diarrhea. 16S rRNA sequencing was used to identify the traits of the intestinal mucosal microbiota. ELISA was used to assess TMAO, transforming growth factor-β1 (TGF-β1), interleukin-1β (IL-1β), and NOD-like receptor thermal protein domain associated protein 3 (NLRP3). Kidney tissue fibrosis was evaluated using Masson's trichrome staining, and immunohistochemical labeling was used to investigate the protein expression of occludin and Zonula Occludens-1(ZO-1) in small intestine tissue. Microbial activity was determined by using fluorescein diacetate (FDA) hydrolysis spectrophotometry. ResultsTMAO showed a positive correlation with NLRP3, IL-1β and TGF-β1, all of which exhibited substantial increases (P < 0.05). Significant renal fibrosis and decreased ZO-1 and occludin expression in small intestine tissues were detected in the model group. The sequencing results revealed alterations in both α and β diversities of small intestinal mucosal microbiota. Elevated TMAO concentrations were potentially associated with increasing Firmicutes/Bacteroidota (F/B) ratios, Streptococcus, Pseudomonas and unclassified Clostridia UCG 014, but with decreasing Rothia and RB41 abundances. ConclusionThis study establishes a link between intestinal microbiota dysbiosis and elevated TMAO concentrations. TMAO can activate inflammatory responses and cytokines, contributing to kidney-yang deficiency syndrome diarrhea via the “gut-kidney axis”. Moreover, TMAO may coincide with disruptions in the intestinal barrier and renal fibrosis. Dysfunction of the “gut-kidney axis” further elevates TMAO levels, perpetuating a vicious cycle.

Correlation between serum trimethylamine-N-oxide and body fat distribution in middle-aged and older adults: a prospective cohort study

BackgroundTrimethylamine-N-oxide (TMAO) is linked with obesity, while limited evidence on its relationship with body fat distribution. Herein, we investigated the associations between serum TMAO and longitudinal change of fat distribution in this prospective cohort study.MethodsData of 1964 participants (40–75y old) from Guangzhou Nutrition and Health Study (GNHS) during 2008–2014 was analyzed. Serum TMAO concentration was quantified by HPLC–MS/MS at baseline. The body composition was assessed by dual-energy X-ray absorptiometry at each 3-y follow-up. Fat distribution parameters were fat-to-lean mass ratio (FLR) and trunk-to-leg fat ratio (TLR). Fat distribution changes were derived from the coefficient of linear regression between their parameters and follow-up duration.ResultsAfter an average of 6.2-y follow-up, analysis of covariance (ANCOVA) and linear regression displayed women with higher serum TMAO level had greater increments in trunk FLR (mean ± SD: 1.47 ± 4.39, P-trend = 0.006) and TLR (mean ± SD: 0.06 ± 0.24, P-trend = 0.011). Meanwhile, for women in the highest TMAO tertile, linear mixed-effects model (LMEM) analysis demonstrated the annual estimated increments (95% CI) were 0.03 (95% CI: 0.003 – 0.06, P = 0.032) in trunk FLR and 1.28 (95% CI: -0.17 – 2.73, P = 0.083) in TLR, respectively. In men, there were no similar significant observations. Sensitivity analysis yielded consistent results.ConclusionSerum TMAO displayed a more profound correlation with increment of FLR and TLR in middle-aged and older community-dwelling women in current study. More and further studies are still warranted in the future.Trial registrationNCT 03179657.

Effects of resveratrol on changes in trimethylamine-N-oxide and circulating cardiovascular factors following exercise training among older adults

PurposeTrimethylamine-N-oxide (TMAO) is a gut-derived metabolite associated with cardiovascular disease (CVD). In preclinical and observational studies, resveratrol and exercise training have been suggested as potential strategies to reduce the systemic levels of TMAO. However, evidence from experimental studies in humans remains unknown. This project examined the dose-dependent effects of a combined resveratrol intervention with exercise training on circulating TMAO and other related metabolite signatures in older adults with high CVD risk. MethodsForty-one older adults [mean (±SD) age of 72.1 (6.8) years] participated in a 12-week supervised center-based, multi-component exercise training intervention [2×/week; 80 min/session] and were randomized to one of two resveratrol dosages [Low: 500 vs. High:1000 mg/day] or a cellulose-based placebo. Serum/plasma were collected at baseline and post-intervention and evaluated for TMAO and associated analytes. ResultsAfter the 12-week intervention, TMAO concentration increased over time, regardless of treatment [mean (±SD) Placebo: 11262 (±3970); Low:13252 (±1193); High: 12661(±3359) AUC; p = 0.04]. Each resveratrol dose produced different changes in metabolite signatures. Low dose resveratrol upregulated metabolites associated with bile acids biosynthesis (i.e., glycochenodeoxycholic acid, glycoursodeoxycholic acid, and glycocholic acid). High dose resveratrol modulated metabolites enriched for glycolysis, and pyruvate, propanoate, β-alanine, and tryptophan metabolism. Different communities tightly correlated to TMAO and resveratrol metabolites were associated with the lipid and vascular inflammatory clinical markers [|r| > 0.4, p < 0.05]. ConclusionThese findings suggest a distinct dose-dependent adaptation response to resveratrol supplementation on circulating metabolite signatures but not on TMAO among high-risk CVD older adults when combined with an exercise training intervention.

Vitamin D is involved in the effects of the intestinal flora and its related metabolite TMAO on perirenal fat and kidneys in mice with DKD

BackgroundVitamin D was shown to directly exert a protective effect on diabetic kidney disease (DKD) in our previous study. However, whether it has an effect on perirenal adipose tissue (PRAT) or the intestinal flora and its metabolites (trimethylamine N-oxide, TMAO) is unclear.MethodsDKD mice were received different concentrations of 1,25-(OH)2D3 for 2 weeks. Serum TNF-α levels and TMAO levels were detected. 16S rRNA sequencing was used to analyze gut microbiota. qPCR was used to detect the expression of TLR4, NF-Κb, PGC1α, and UCP-1 in kidney and adipose tissue. Histological changes in kidney and perirenal adipose tissue were observed using HE, PAS, Masson and oil red staining. Immunofluorescence and immunohistochemistry were used to detect the expression of VDR, PGC1α, podocin, and UCP-1 in kidney and adipose tissue. Electron microscopy was used to observe the pathological changes in the kidney. VDR knockout mice were constructed to observe the changes in the gut and adipose tissue, and immunofluorescence and immunohistochemistry were used to detect the expression of UCP-1 and collagen IV in the kidney.Results1,25-(OH)2D3 could improve the dysbiosis of the intestinal flora of mice with DKD, increase the abundance of beneficial bacteria, decrease the abundance of harmful bacteria, reduce the pathological changes in the kidney, reduce fat infiltration, and downregulate the expression of TLR4 and NF-κB in kidneys. The serum TMAO concentration in mice with DKD was significantly higher than that of the control group, and was significantly positively correlated with the urine ACR. In addition, vitamin D stimulated the expression of the surface markers PGC1α, UCP-1 and VDR in the PRAT in DKD mice, and TMAO downregulated the expression of PRAT and renal VDR.ConclusionsThe protective effect of 1,25-(OH)2D3 in DKD mice may affect the intestinal flora and its related metabolite TMAO on perirenal fat and kidneys.

Unlocking the microbial diversity and the chemical changes throughout the fermentation process of “hákarl”, Greenland shark

Hákarl is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (Somniosus microcephalus). However, little is known about the chemical and microbial changes occurring during the process. In this small-scale industrial study, fresh and frozen shark meat was fermented for eight and seven weeks, respectively, and then dried for five weeks. During the fermentation, trimethylamine N-oxide levels decreased to below the limit of detection within five weeks and pH increased from about 6 to 9. Simultaneously, trimethylamine and dimethylamine levels increased significantly. Total viable plate counts, and specific spoilage organisms increased during the first weeks of the fermentation period but decreased during drying. Culture-independent analyses (16S rRNA) revealed gradual shifts in the bacterial community structure as fermentation progressed, dividing the fermentation process into three distinct phases but stayed rather similar throughout the drying process. During the first three weeks of fermentation, Photobacterium was dominant in the fresh group, compared to Pseudoalteromonas in the frozen group. However, as the fermentation progressed, the groups became more alike with Atopostipes, Pseudomonas and Tissierella being dominant. The PCA analysis done on the chemical variables and 16S rRNA analysis variables confirmed the correlation between high concentrations of TMAO and Pseudoalteromonas, and Photobacterium at the initial fermentation phase. During the final fermentation phase, correlation was detected between high concentrations of TMA/DMA and Atopostipes, Pseudomonas and Tissierella. The results indicate the possibility to shortening the fermentation period and it is suggested that the microbial community can potentially be standardized with starter cultures to gain an optimal fermentation procedure.

Trimethylamine-N-oxide paradoxically depresses contractile function while activating mitochondrial respiration in mouse hearts.

Trimethylamine-N-oxide (TMAO) is an end-product of gut-microbiome metabolism linked to cardiovascular disease (CVD). However, precise cardiovascular influences of the TMAO concentrations reported in early or severe disease remain to be detailed. We investigated acute effects of TMAO on cardiac contractile, coronary and mitochondrial function. Male C57Bl/6 mouse hearts were Langendorff perfused to assess concentration-dependent effects of TMAO (1-300 µM) on left ventricular (LV) function, coronary flow and select protein expression. Effects of 10 and 100 µM TMAO on LV mitochondrial function were examined via respirometry. TMAO at 10-300 µM concentration-dependently depressed LV contractile function, with coronary flow paralleling changes in isovolumic pressure development. Direct coronary effects were evident at >30 µM TMAO in hearts performing minimal isovolumic work, though this response was reduced by >65%. In contrast, exposure to 10 or 100 µM TMAO increased mitochondrial complex I, II and maximal respiratory fluxes while appearing to reduce outer membrane integrity. Expression of phospho-AMPKα and total GSK-3β declined. Acute exposure to TMAO levels reported in advanced CVD significantly inhibits cardiac contractility and induces modest coronary constriction while paradoxically over-activating mitochondrial respiration.

Impact of dietary choline on lipid metabolism and atherosclerosis development in apoEKO mice deficient or overexpressing apolipoprotein A-I: Selected Abstract - XVI SITeCS Congress

TMAO, a metabolite of dietary choline, is considered a pro-atherogenic molecule for its ability to interfere with the reverse cholesterol transport, in which apolipoprotein A-I and HDL play a key role. In the present work it was evaluated how TMAO impacts on the development of atherosclerosis in mice with different levels of apoA-I/HDL. Mice deficient in both murine apoA-I and apoE (DKO) and DKO mice overexpressing human apoA-I (DKO/hA-I), characterized by extremely low or high plasma HDL levels respectively, were fed for 16 weeks two standard rodent diets, differing only in their choline content (0.09% or 1.2%). At the end of the dietary treatment, atherosclerosis development was quantified at the aortic sinus, targeted plasma metabolomics was performed, and gene expression was evaluated in liver, duodenum, jejunum and ileum. With both diets, DKO mice developed much larger plaques than DKO/hA-I mice. High-choline diet increased plasma TMAO levels in both genotypes. Interestingly, a worsening of plaque development by high choline diet occurred in DKO/hA-I mice only (0.057±0.048 mm2 vs 0.0988±0.064 mm2, p&lt;0.01). Plasma metabolomics indicated that choline supplementation, only in the presence of HDL, significantly increased the concentration of some ceramide species in addition to several markers of impaired kidney function. High-choline diet increased the hepatic gene expression of Fmo1 and Fmo2 in DKO/hA-I, whereas the expression of Scarb1 was lower in DKO/hA-I compared to DKO mice, regardless of the dietary treatment. Intestinal expression of genes involved in inflammatory response and in lipid metabolism was comparable between genotypes and was not modified by choline supplementation. In conclusion, high choline diet increased plasma TMAO concentration in both genotypes, but affected atherosclerosis development, plasma metabolome and hepatic gene expression only in high HDL mice. Intestinal gene expression was not affected neither by genotype nor by dietary choline content.

Chain length and amino acid composition dependence of coil-globule transition in intrinsically disordered proteins.

A fundamental question related to intrinsically disordered proteins (IDPs) is whether they undergo a coil-to-globule transition with changes in cosolvent conditions. IDPs are hetero-polymers and finite in size. The chain length and amino acid composition could lead to the varying extent of compaction in IDPs and the coil-to-globule transition (theta condition). To probe the theta condition in polypeptides, we studied the behavior of polyleucine and polyglutamine with six different chain lengths (N = 16 to 512) in various concentrations (0 to 8 M) of Urea (denaturant) and TMAO (osmolyte) using coarse-grained models and computer simulations. The Flory scaling exponent of polyleucine (polyglutamine) undergoes a transition from approximately 0.6 (0.6) to 0.3 (0.5) with increasing N in water. We observed that the theta condition for both the IDPs strongly depends on N and varies as N−0.5. Depending on N, polyglutamine (polyleucine) chains reach the theta condition at different [TMAO] ([TMAO] or [Urea]), confirming that in addition to chain length, the amino acid composition also influences the theta solvent condition for the IDPs. Moreover, the theta point for smaller chain lengths (N = 16 to 64) calculated using the structure factor mimicking the small-angle X-ray scattering (SAXS) experiments and using pair distances mimicking fluorescence resonance energy transfer (FRET) experiments are in disagreement. The theta condition computed using the structure factor and pair distances converge to the same point only at large N. As the theta condition is correlated with the critical condition of liquid-liquid phase separation (LLPS) for IDPs, we predict that LLPS propensity of IDPs will increase with N.

Residual Risk of Trimethylamine‐N‐Oxide and Choline for Stroke Recurrence in Patients With Intensive Secondary Therapy

Background Trimethylamine N-oxide (TMAO) contributes to cardiovascular disease through its prothrombotic, proatherothrombotic, and proinflammatory effects. We aimed to evaluate whether residual risk of recurrent stroke of TMAO and its precursor choline remain among patients who received dual-antiplatelet therapy and intensive lipid-lowering therapy and with a low inflammation level (high-sensitivity C-reactive protein <2 mg/L on admission). Methods and Results Patients with ischemic stroke or transient ischemic attack were enrolled from the CNSR-III (Third China National Stroke Registry) in China. Plasma TMAO and choline concentrations at baseline were measured in 9793 participants using liquid chromatography-mass spectrometry. The primary outcome was a new stroke within 1 year. Multivariable-adjusted hazard ratios were calculated using Cox regression models to investigate the associations of TMAO and choline with stroke recurrence. Among all patients, elevated TMAO and choline levels were associated with an increased risk of recurrent stroke (adjusted hazard ratios, 1.28 [95% CI, 1.12-1.45]; and 1.50 [95% CI, 1.32-1.71], respectively). Moreover, elevated TMAO and choline levels were associated with an increased risk of recurrent stroke among patients who received dual-antiplatelet therapy (1.65 [95% CI, 1.28-2.13]; and 1.70 [95% CI, 1.32-2.19], respectively), intensive lipid-lowering therapy (1.49 [95% CI, 1.15-1.94]; and 1.49 [95% CI, 1.15-1.92], respectively), with high-sensitivity C-reactive protein <2 mg/L (1.39 [95% CI, 1.14-1.69]; and 1.88 [95% CI, 1.53-2.30], respectively), and concurrently received dual-antiplatelet therapy, intensive lipid-lowering therapy and with high-sensitivity C-reactive protein <2 mg/L (3.57 [95% CI, 1.73-7.38]; and 2.19 [95% CI, 1.16-4.16], respectively). Conclusions TMAO and choline were risk factors for recurrent stroke independent of dual-antiplatelet therapy, intensive lipid-lowering therapy at discharge, and low inflammation on admission.

Gut microbiota–derived metabolite trimethylamine-N-oxide and multiple health outcomes: an umbrella review and updated meta-analysis

ABSTRACTBackgroundTrimethylamine-N-oxide (TMAO) is a gut microbiota–derived metabolite produced from dietary nutrients. Many studies have discovered that circulating TMAO concentrations are linked to a wide range of health outcomes.ObjectivesThis study aimed to summarize health outcomes related to circulating TMAO concentrations.MethodsWe searched the Embase, Medline, Web of Science, and Scopus databases from inception to 15 February, 2022 to identify and update meta-analyses examining the associations between TMAO and multiple health outcomes. For each health outcome, we estimated the summary effect size, 95% prediction CI, between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. These metrics were used to evaluate the evidence credibility of the identified associations.ResultsThis umbrella review identified 24 meta-analyses that investigated the association between circulating TMAO concentrations and health outcomes including all-cause mortality, cardiovascular diseases (CVDs), diabetes mellitus (DM), cancer, and renal function. We updated these meta-analyses by including a total of 82 individual studies on 18 unique health outcomes. Among them, 14 associations were nominally significant. After evidence credibility assessment, we found 6 (33%) associations (i.e., all-cause mortality, CVD mortality, major adverse cardiovascular events, hypertension, DM, and glomerular filtration rate) to present highly suggestive evidence.ConclusionsTMAO might be a novel biomarker related to human health conditions including all-cause mortality, hypertension, CVD, DM, cancer, and kidney function. Further studies are needed to investigate whether circulating TMAO concentrations could be an intervention target for chronic disease.This review was registered at www.crd.york.ac.uk/prospero/ as CRD42021284730.

Integrating Choline and Specific Intestinal Microbiota to Classify Type 2 Diabetes in Adults: A Machine Learning Based Metagenomics Study.

Emerging evidence is examining the precise role of intestinal microbiota in the pathogenesis of type 2 diabetes. The aim of this study was to investigate the association of intestinal microbiota and microbiota-generated metabolites with glucose metabolism systematically in a large cross-sectional study in China. 1160 subjects were divided into three groups based on their glucose level: normal glucose group (n=504), prediabetes group (n=394), and diabetes group (n=262). Plasma concentrations of TMAO, choline, betaine, and carnitine were measured. Intestinal microbiota was measured in a subgroup of 161 controls, 144 prediabetes and 56 diabetes by using metagenomics sequencing. We identified that plasma choline [Per SD of log-transformed change: odds ratio 1.36 (95 confidence interval 1.16, 1.58)] was positively, while betaine [0.77 (0.66, 0.89)] was negatively associated with diabetes, independently of TMAO. Individuals with diabetes could be accurately distinguished from controls by integrating data on choline, and certain microbiota species, as well as traditional risk factors (AUC=0.971). KOs associated with the carbohydrate metabolism pathway were enhanced in individuals with high choline level. The functional shift in the carbohydrate metabolism pathway in high choline group was driven by species Ruminococcus lactaris, Coprococcus catus and Prevotella copri. We demonstrated the potential ability for classifying diabetic population by choline and specific species, and provided a novel insight of choline metabolism linking the microbiota to impaired glucose metabolism and diabetes.

In silico studies of the human IAPP in the presence of osmolytes

The human islet amyloid polypeptide or amylin is secreted along with insulin by pancreatic islets. Under the drastic environmental conditions, amylin can aggregate to form amyloid fibrils. This amyloid plaque of hIAPP in the pancreatic cells is the cause of type II diabetes. Early stages of amylin aggregates are more cytotoxic than the matured fibrils. Here, we have used the all-atom molecular dynamic simulation to see the effect of water, TMAO, urea and urea/TMAO having ratio 2:1 of different concentrations on the amylin protein. Our study suggest that the amylin protein forms β-sheets in its monomeric form and may cause the aggregation of protein through the residue 13-17 and the C-terminal region. α-Helical content of protein increases with an increase in TMAO concentration by decreasing the SASA value of protein, increase in intramolecular hydrogen bonds and on making the short-range hydrophobic interactions. Electrostatic potential surfaces show that hydrophobic groups are buried and normalised configurational entropy of backbone, and side-chain atoms is lesser in the presence of TMAO, whereas opposite behaviour is obtained in the case of urea. Counteraction effect of TMAO using Kast model towards urea is also observed in ternary solution of urea/TMAO.

TMAO Response to a High-Fat High-Sugar Meal Challenge in Generally Healthy United States Adults

ObjectivesTrimethylamine n-oxide (TMAO) is linked to the gut microbiome's metabolism of choline, carnitine, and betaine and is associated with adverse cardiovascular health. In a secondary analysis, we assessed the plasma TMAO response to a high-fat high-sugar meal challenge devoid of choline, carnitine, or betaine in metabolically healthy male (n = 48) and female (n = 49) participants residing near Davis, California, USA.MethodsThe standardized meal challenge was a 3000-gram shake containing 60% kilocalories from fat (shortening and palm oil), 25% kilocalories from carbohydrate (granulated white sugar), and 15% kilocalories from protein (pasteurized egg white). The shake contained limited amounts of direct TMAO-precursors including 2.9 mg of choline and 0.76 mg of betaine. Blood samples were collected at fasting and 0.5, 3, and 6 hours after consuming the meal challenge. TMAO was measured by liquid chromatography-high resolution mass spectrometry using the MxP Quant 500 kit (Biocrates, Innsbruck, Austria). Differences in TMAO concentration by time were assessed by ANOVA and values are means ± standard deviation.ResultsTMAO response demonstrated a post-prandial rise in concentration that peaked at 3 hours and returned to fasting levels by 6 hours. Mean TMAO levels at fasting, 0.5, 3, and 6 hours were 5.27 ± 3.43 μM, 6.09 ± 6.01 μM, 6.87 ± 8.11 μM, 4.76 ± 4.00 μM, respectively. Significant differences were observed between fasting and 3 hours (P = 0.039), and 3 and 6 hours (P = 0.011).ConclusionsPlasma TMAO concentration was affected by a high-fat high-sugar meal challenge despite providing limited amounts of direct TMAO-precursors. The circadian rhythm of the gut microbiome or the host, or the gut microbiome's utilization of phosphatidylcholine from biological sources may contribute to these results. Understanding the regulation of TMAO and its relationship to meals is critical to identifying its role in the etiology of diabetes and cardiovascular disease.Funding SourcesThis work was funded in part by the USDA-Agricultural Research Service (2032–51,530-025–00D) and the National Institute of Health (RO1HL148110).

Diet, Fecal Microbiome, and Trimethylamine N-Oxide in a Cohort of Metabolically Healthy United States Adults.

TMAO is elevated in individuals with cardiometabolic diseases, but it is unknown whether the metabolite is a biomarker of concern in healthy individuals. We conducted a cross-sectional study in metabolically healthy adults aged 18–66 years with BMI 18–44 kg/m2 and assessed the relationship between TMAO and diet, the fecal microbiome, and cardiometabolic risk factors. TMAO was measured in fasted plasma samples by liquid chromatography mass spectrometry. The fecal microbiome was assessed by 16S ribosomal RNA sequencing and recent food intake was captured by multiple ASA24 dietary recalls. Endothelial function was assessed via EndoPAT. Descriptive statistics were computed by fasting plasma TMAO tertiles and evaluated by ANOVA and Tukey’s post-hoc test. Multiple linear regression was used to assess the relationship between plasma TMAO and dietary food intake and metabolic health parameters. TMAO concentrations were not associated with average intake of animal protein foods, fruits, vegetables, dairy, or grains. TMAO was related to the fecal microbiome and the genera Butyribrio, Roseburia, Coprobaciullus, and Catenibacterium were enriched in individuals in the lowest versus the highest TMAO tertile. TMAO was positively associated with α-diversity and compositional differences were identified between groups. TMAO was not associated with classic cardiovascular risk factors in the healthy cohort. Similarly, endothelial function was not related to fasting TMAO, whereas the inflammatory marker TNF-α was significantly associated. Fasting plasma TMAO may not be a metabolite of concern in generally healthy adults unmedicated for chronic disease. Prospective studies in healthy individuals are necessary.

Paradox of trimethylamine-N-oxide, the impact of malnutrition on microbiota-derived metabolites and septic patients

BackgroundTrimethylamine N-oxide (TMAO) is a microbiota-derived metabolite, which is linked to vascular inflammation and atherosclerosis in cardiovascular (CV) diseases. But its effect in infectious diseases remains unclear. We conducted a single-center prospective study to investigate association of TMAO with in-hospital mortality in septic patients admitted to an intensive care unit (ICU).MethodsTotally 95 septic, mechanically ventilated patients were enrolled. Blood samples were obtained within 24 h after ICU admission, and plasma TMAO concentrations were determined. Septic patients were grouped into tertiles according to TMAO concentration. The primary outcome was in-hospital death, which further classified as CV and non-CV death. Besides, we also compared the TMAO concentrations of septic patients with 129 non-septic patients who were admitted for elective coronary angiography (CAG).ResultsSeptic patients had significantly lower plasma TMAO levels than did subjects admitted for CAG (1.0 vs. 3.0 μmol/L, p < 0.001). Septic patients in the lowest TMAO tertile (< 0.4 μmol/L) had poorer nutrition status and were given longer antibiotic courses before ICU admission. Circulating TMAO levels correlated positively with daily energy intake, the albumin and prealbumin concentration. Compared with those in the highest TMAO tertile, septic patients in the lowest TMAO tertile were at greater risk of non-CV death (hazard ratio 2.51, 95% confidence interval 1.21–5.24, p = 0.014). However, TMAO concentration was no longer an independent predictor for non-CV death after adjustment for disease severity and nutritional status.ConclusionPlasma TMAO concentration was inversely associated with non-CV death among extremely ill septic patients, which could be characterized as TMAO paradox. For septic patients, the impact of malnutrition reflected by circulating TMAO levels was greater than its pro-inflammatory nature.

Circulating trimethylamine-N-oxide is associated with all-cause mortality in subjects with nonalcoholic fatty liver disease.

Background and AimsTrimethylamine‐N‐oxide (TMAO), a gut microbiota‐liver metabolite, has been associated with cardiometabolic disease. However, whether TMAO is associated with nonalcoholic fatty liver disease (NAFLD) and NAFLD‐related health outcomes remains unclear. We aimed to investigate the association of TMAO with NAFLD and to assess the extent to which the association of TMAO with all‐cause mortality is dependent on the presence of NAFLD in the general population.MethodsWe included 5292 participants enrolled in the Prevention of Renal and Vascular End‐stage Disease (PREVEND) cohort study. Cox proportional‐hazards regression analyses were performed to study the association of TMAO with all‐cause mortality in subjects with and without a fatty liver index (FLI) ≥60, which was used as a proxy of NAFLD.ResultsDuring a median follow‐up of 8.2 years, 307 subjects died, of whom 133 were classified with NAFLD. TMAO was positively and independently associated with baseline FLI (Std β 0.08, 95% CI 0.05, 0.11, P < .001). Higher TMAO was associated with increased risk of all‐cause mortality in subjects with NAFLD, in crude analysis (hazard ratio [HR] per 1 SD, 2.55, 95% CI 1.60, 4.05, P < .001) and after full adjustment (adjHR 1.90, 95% CI 1.18, 3.04, P = .008). Such an association was not present in subjects without NAFLD (crude HR 1.14, 95% CI 0.81, 1.71, P = .39; adjHR 0.95, 95% CI 0.65, 1.39, P = .78).ConclusionThis prospective study revealed that plasma concentrations of TMAO were associated with all‐cause mortality in subjects with NAFLD, independently of traditional risk factors.

Circulating concentrations of TMAO is associated with all-cause mortality in subjects with Non-alcoholic fatty liver disease. Results from a dutch prospective cohort

Circulating concentrations of TMAO is associated with all-cause mortality in subjects with Non-alcoholic fatty liver disease. Results from a dutch prospective cohort

Lactic acid bacteria prevent both periodontitis and atherosclerosis exacerbated by periodontitis in spontaneously hyperlipidemic mice.

Recent studies have shown a link between periodontal disease and cardiovascular disease. We have previously reported that oral administration of Porphyromonas gingivalis (Pg) accelerates atherosclerosis in apolipoprotein E-deficient spontaneously hyperlipidemic (Apoeshl ) mice. This study evaluated the potential of lactic acid bacteria (LAB) to change the intestinal flora changes induced by periodontopathic bacteria and to prevent/slow down the development of atherosclerosis. Lactobacillus gasseri O3-2 (Lg) was orally intubated in Apoeshl mice for 5weeks. Three weeks after oral intubation, the mice were orally infected with Pg for 2weeks. Thirty days after the last infection with Pg, Lg+Pg-treated mice showed a significant reduction in alveolar bone loss compared to the Pg-treated group. The Lg treatment restored the Pg-induced intestinal flora disturbance to normal. Furthermore, a significant decrease in atherosclerotic plaque lesion size and suppressed inflammatory cytokine production in the aorta were detected in the Lg+Pg-treated group. In contrast, blood concentrations of TMAO, histidine, and carnitine were enhanced by the Lg treatment but decreased by Lg+Pg treatment. These results suggest that oral Lg treatment is effective in preventing periodontitis and atherosclerosis.

Worldwide distribution and depth limits of decapod crustaceans (Penaeoidea, Oplophoroidea) across the abyssal-hadal transition zone of eleven subduction trenches and five additional deep-sea features

Abstract Decapod crustaceans are conspicuous members of marine benthic communities to at least 7,700 m deep. To assess the bathymetric extent of this taxonomic group, baited landers were deployed to across the abyssal-hadal transition zone of 11 subduction trenches spanning the Pacific, Atlantic, Southern, and Indian oceans and additional sites. Decapods were dominated by penaeid shrimps (superfamily Penaeoidea), in particular Benthesicymus Spence Bate, 1881 and Cerataspis Gray, 1828, with the former being found deeper. Benthesicymus cf. crenatus Spence Bate, 1881 was observed in the Kermadec, Mariana, New Hebrides, Puerto Rico, Peru-Chile, Tonga, San Cristobal, and Santa Cruz trenches, plus the South Fiji Basin and the Wallaby-Zenith Fracture Zone. They were not recorded in the Abaco Canyon, Agulhas Fracture Zone, Java Trench, or any of the polar locations. Cerataspis cf. monstrosus Gray, 1828 was present in the Kermadec, Mariana, New Hebrides, Puerto Rico, and Java trenches, the Abaco Canyon, Agulhas Fracture Zone, Wallaby-Zenith Fracture Zone and the South Fiji Basin, but absent from the Tonga, San Cristobal and Santa Cruz trenches. Hymenopenaeus nereus (Faxon, 1893) was only recorded in the Peru-Chile Trench. Unidentified species belonging to superfamily Oplophoroidea were observed to a maximum depth of 6,931 m. Decapods are thus are primarily represented at hadal depths by penaeoid shrimps, consistently present at tropical and temperate latitudes to ~7,700 m, while absent from equivalent depths in polar regions. Their maximum depth may be limited due to hydrostatic pressure, while potentially affected by temperature and oxygen in some instances. Muscle samples of three specimens from 6,000 m (Mariana and Kermadec trenches) were found to have high levels of trimethylamine N-oxide (TMAO; 260 mmol kg–1), the major piezolyte, a protectant against hydrostatic pressure, in other deep-sea organisms. We speculate that physiological limits to TMAO concentration may prevent them from inhabiting the greatest hadal depths.

Interactions of a DNA G-quadruplex with TMAO and urea: a molecular dynamics study on co-solute compensation mechanisms.

We study the individual and combined influence of TMAO and urea on a basket-type DNA G-quadruplex by means of atomistic molecular dynamics (MD) simulations. In combination with the Kirkwood-Buff theory of solutions, we propose a simple mechanism to elucidate the impact of TMAO and urea on the G-quadruplex. Our results reveal the importance of the molecular accumulation around the DNA in terms of stabilizing or destabilizing effects. The results for mixtures show only a weak interaction between both co-solutes, which highlights the additivity of contributions. Despite the fact, that TMAO can to some extent compensate the adverse impact of urea on the G-quadruplex structure, the destabilizing influence is not completely eliminated. This observation opens the door for further research on selective stabilization of DNA G-quadruplexes by modulating the concentrations of TMAO and urea in solution.