Meldonium decreases the diet-increased plasma levels of trimethylamine N-oxide, a metabolite associated with atherosclerosis

Gut dysbiosis-related thrombosis in inflammatory bowel disease: Potential disease mechanisms and emerging therapeutic strategies

Patients with inflammatory bowel disease (IBD) have an increased risk of developing venous thromboembolic events, which have a considerable impact on morbidity and mortality. Chronic inflammation plays a crucial role in the pathogenesis of thrombotic events in patients with IBD. However, many unresolved questions remain, particularly regarding the mechanisms that determine the persistent inflammatory state independent of disease activity. This review explored the role of gut microbiota dysbiosis and intestinal barrier dysfunction, which are considered distinctive features of IBD, in determining pro-thrombotic tendencies. Gut-derived endotoxemia due to the translocation of bacterial lipopolysaccharides (LPS) from the intestine to the bloodstream and the bacterial metabolite trimethylamine-N-oxide (TMAO) are the most important molecules involved in gut dysbiosis-related thrombosis. The pathogenic prothrombotic pathways linked to LPS and TMAO have been discussed. Finally, we present emerging therapeutic approaches that can help reduce LPS-mediated endotoxemia and TMAO, such as restoring intestinal eubiosis, normalizing intestinal barrier function, and counterbalancing the effects of LPS and TMAO.

The Association of Circulating L-Carnitine, γ-Butyrobetaine and Trimethylamine N-Oxide Levels with Gastric Cancer

Our study aimed to evaluate the association between gastric cancer (GC) and higher concentrations of the metabolites L-carnitine, γ-butyrobetaine (GBB) and gut microbiota-mediated trimethylamine N-oxide (TMAO) in the circulation. There is evidence suggesting that higher levels of TMAO and its precursors in blood can be indicative of either a higher risk of malignancy or indeed its presence; however, GC has not been studied in this regard until now. Our study included 83 controls without high-risk stomach lesions and 105 GC cases. Blood serum L-carnitine, GBB and TMAO levels were measured by ultra-high-performance liquid chromatography–mass spectrometry (UPLC/MS/MS). Although there were no significant differences between female control and GC groups, we found a significant difference in circulating levels of metabolites between the male control group and the male GC group, with median levels of L-carnitine reaching 30.22 (25.78–37.57) nmol/mL vs. 37.38 (32.73–42.61) nmol/mL (p < 0.001), GBB–0.79 (0.73–0.97) nmol/mL vs. 0.97 (0.78–1.16) nmol/mL (p < 0.05) and TMAO–2.49 (2.00–2.97) nmol/mL vs. 3.12 (2.08–5.83) nmol/mL (p < 0.05). Thus, our study demonstrated the association between higher blood levels of L-carnitine, GBB, TMAO and GC in males, but not in females. Furthermore, correlations of any two investigated metabolites were stronger in the GC groups of both genders in comparison to the control groups. Our findings reveal the potential role of L-carnitine, GBB and TMAO in GC and suggest metabolic differences between genders. In addition, the logistic regression analysis revealed that the only significant factor in terms of predicting whether the patient belonged to the control or to the GC group was the blood level of L-carnitine in males only. Hence, carnitine might be important as a biomarker or a risk factor for GC, especially in males.

Gut-Derived Metabolite, Trimethylamine-N-oxide (TMAO) in Cardio-Metabolic Diseases: Detection, Mechanism, and Potential Therapeutics

Trimethylamine N-oxide (TMAO) is a biologically active gut microbiome-derived dietary metabolite. Recent studies have shown that high circulating plasma TMAO levels are closely associated with diseases such as atherosclerosis and hypertension, and metabolic disorders such as diabetes and hyperlipidemia, contributing to endothelial dysfunction. There is a growing interest to understand the mechanisms underlying TMAO-induced endothelial dysfunction in cardio-metabolic diseases. Endothelial dysfunction mediated by TMAO is mainly driven by inflammation and oxidative stress, which includes: (1) activation of foam cells; (2) upregulation of cytokines and adhesion molecules; (3) increased production of reactive oxygen species (ROS); (4) platelet hyperreactivity; and (5) reduced vascular tone. In this review, we summarize the potential roles of TMAO in inducing endothelial dysfunction and the mechanisms leading to the pathogenesis and progression of associated disease conditions. We also discuss the potential therapeutic strategies for the treatment of TMAO-induced endothelial dysfunction in cardio-metabolic diseases.

Atherosclerotic patients with diabetes mellitus may break through the threshold of healthy TMAO levels formed by long-term statins therapy

Background

Cardiovascular disease (CVD) is the leading course of disease-related death in both developed and developing countries. Atherosclerosis is main pathology of CVD, and its severity is thought to be related to trimethylamine N-oxide (TMAO) level in plasma. Therefore, it is necessary to deeply understand the synergistic patterns between TMAO and other contribution variables to atherosclerosis, allowing for effective and timely monitoring or intervention.

Methods

A total of 359 participants were recruited in our study, including 190 atherosclerosis patients, 82 MI or stroke patients, 68 non-atherosclerosis controls and 19 healthy controls. Information on their risk associated with atherosclerosis and plasma TMAO concentration were collected. LASSO regression, multivariate analysis and univariate analysis were then performed to confirm the correlation between TMAO level and risk factors of atherosclerosis.

Results

Compared to patients and non-atherosclerosis controls, healthy participants had a normal BMI range (lower than 24), lower triglyceride concentration, and healthy lifestyle habits (no smoking and low salt diet). However, under backgrounds of statins treatment and balanced dietary preferences, TMAO levels were not significantly different among patients, non-atherosclerosis controls and healthy controls. Using LASSO regression model, four indicators was identified to have contribution to TMAO levels, including diabetes, atherosclerosis, low-density lipoprotein and total cholesterol. Subsequent univariate analysis further confirmed that the presence or absence of diabetes had a decisive effect on patients' plasma TMAO levels, even though they had been taking statin lipid-lowering drugs for a long time.

Conclusion

Diabetics have abnormally high plasma TMAO levels even under continuous statins treatment, which may contribute to the development and progression of atherosclerosis. Therefore, it is necessary to focus on monitoring TMAO levels in diabetic patients to reduce adverse cardiovascular events in diabetic patients.

The Role of the Gut Microbiome and Trimethylamine Oxide in Atherosclerosis and Age-Related Disease

The gut microbiome plays a major role in human health, and gut microbial imbalance or dysbiosis is associated with disease development. Modulation in the gut microbiome can be used to treat or prevent different diseases. Gut dysbiosis increases with aging, and it has been associated with the impairment of gut barrier function leading to the leakage of harmful metabolites such as trimethylamine (TMA). TMA is a gut metabolite resulting from dietary amines that originate from animal-based foods. TMA enters the portal circulation and is oxidized by the hepatic enzyme into trimethylamine oxide (TMAO). Increased TMAO levels have been reported in elderly people. High TMAO levels are linked to peripheral artery disease (PAD), endothelial senescence, and vascular aging. Emerging evidence showed the beneficial role of probiotics and prebiotics in the management of several atherogenic risk factors through the remodeling of the gut microbiota, thus leading to a reduction in TMAO levels and atherosclerotic lesions. Despite the promising outcomes in different studies, the definite mechanisms of gut dysbiosis and microbiota-derived TMAO involved in atherosclerosis remain not fully understood. More studies are still required to focus on the molecular mechanisms and precise treatments targeting gut microbiota and leading to atheroprotective effects.

Microbiota Effect on Trimethylamine N-Oxide Production: From Cancer to Fitness-A Practical Preventing Recommendation and Therapies

Trimethylamine N-oxide (TMAO) is a microbial metabolite derived from nutrients, such as choline, L-carnitine, ergothioneine and betaine. Recently, it has come under the spotlight for its close interactions with gut microbiota and implications for gastrointestinal cancers, cardiovascular disease, and systemic inflammation. The culprits in the origin of these pathologies may be food sources, in particular, high fat meat, offal, egg yolk, whole dairy products, and fatty fish, but intercalated between these food sources and the production of pro-inflammatory TMAO, the composition of gut microbiota plays an important role in modulating this process. The aim of this review is to explain how the gut microbiota interacts with the conversion of specific compounds into TMA and its oxidation to TMAO. We will first cover the correlation between TMAO and various pathologies such as dysbiosis, then focus on cardiovascular disease, with a particular emphasis on pro-atherogenic factors, and then on systemic inflammation and gastrointestinal cancers. Finally, we will discuss primary prevention and therapies that are or may become possible. Possible treatments include modulation of the gut microbiota species with diets, physical activity and supplements, and administration of drugs, such as metformin and aspirin.

Data on cardiac and vascular functionality in ex vivo and in vivo models following acute administration of trimethylamine N-oxide

This dataset describes in detail the outcomes of acute trimethylamine N-oxide (TMAO) administration on cardiac, vascular and mitochondrial functionality in ex vivo and in vivo models. The accumulation of TMAO in target tissues was assessed after performing heart perfusion or by incubating aortic tissue in a solution containing TMAO. To evaluate the impact of TMAO on mitochondrial function, the aortic rings and heart homogenates of Wistar rats were incubated in a solution containing [9,10-³H] palmitate (5 µCi/ml) or D-[U-¹⁴C] glucose (0.625 µCi/ml) in the presence or absence of TMAO with subsequent measurement of substrate oxidation and uptake. The effects of TMAO on the vascular reactivity of isolated conductance and resistance vessels were tested by measuring their response to acetylcholine and sodium nitroprusside. The impact of elevated TMAO levels on cardiac function and infarct size caused by ischemia-reperfusion injury was evaluated in Langendorff perfused heart model. Normal and forced heart functioning was analyzed by echocardiography in CD-1 mouse acute cardiac stress model induced by isoproterenol (10 µg/mouse) upon single and 7 repeated daily administrations of TMAO (120 mg/kg). The data presented in the manuscript provide valuable information on measurements performed under conditions of acutely elevated TMAO levels in experimental models of cardiac and vascular function and energy metabolism. Furthermore, the data have high reuse potential as they could be applied in the planning of future in vitro, ex vivo, and in vivo studies addressing the molecular mechanisms targeted by elevated levels of TMAO.

Pathogenic or Therapeutic: The Mediating Role of Gut Microbiota in Non-Communicable Diseases

Noncommunicable diseases (NCDs) lead to 41 million deaths every year and account for 71% of all deaths worldwide. Increasing evidence indicates that gut microbiota disorders are closely linked to the occurrence and development of diseases. The gut microbiota, as a potential transmission medium, could play a key role in the transmission and treatment of diseases. The gut microbiota makes noncommunicable diseases communicable. New methods of the prevention and treatment of these diseases could be further explored through the gut microbiota.

Fasting-Mimicking Diet Reduces Trimethylamine N-Oxide Levels and Improves Serum Biochemical Parameters in Healthy Volunteers

Elevated plasma levels of trimethylamine N-oxide (TMAO) have been proposed as a diet-derived biomarker of cardiometabolic disease risk. Caloric restriction is the most common dietary intervention used to improve cardiometabolic health; however, novel trends suggest a fasting-mimicking diet (FMD) as a more feasible alternative. FMD is a variation of intermittent fasting, based on caloric restriction and limitation of protein sources of animal origin, applied in daily cycles during a 5-day period. As TMAO is intensively produced by gut microbiota after the consumption of animal-derived products, we aim to investigate whether a 5-day FMD affects plasma TMAO levels and markers of metabolic health. To investigate whether an increase in vegetable intake possesses similar effects on TMAO levels and metabolic parameters, healthy volunteers (n = 24) were subjected to a 5-day FMD and 19 volunteers served as a reference group (VEG). This group of volunteers consumed an additional four servings of vegetables per day, but otherwise stayed on their usual diet. FMD resulted in a twofold decrease in plasma TMAO levels, which was not evident in the volunteers from the VEG group. Moreover, FMD led to a weight loss of 2.8 ± 0.2 kg and a subsequent reduction in BMI compared to baseline. The FMD group exhibited a significant elevation in plasma ketone bodies (14-fold compared to baseline) and a decrease in IGF-1 levels by 37 ± 8 ng/mL. Since fasting glucose and C-peptide levels decreased, all volunteers in the FMD group showed improved insulin sensitivity and a decreased HOMA-IR index. In contrast, in the VEG group, only a slight reduction in plasma levels of fasting glucose and triglycerides was noted. In conclusion, we show that FMD is a viable strategy to reduce plasma levels of TMAO by limiting caloric intake and animal-derived protein consumption. The reduction in the level of TMAO could be an additional benefit of FMD, leading to a reduced risk of cardiometabolic diseases.

Balancing the Equation: A Natural History of Trimethylamine and Trimethylamine-N-oxide

Trimethylamine (TMA) and its N-oxide (TMAO) are ubiquitous in prokaryote and eukaryote organisms as well as in the environment, reflecting their fundamental importance in evolutionary biology, and their diverse biochemical functions. Both metabolites have multiple biological roles including cell-signaling. Much attention has focused on the significance of serum and urinary TMAO in cardiovascular disease risk, yet this is only one of the many facets of a deeper TMA-TMAO partnership that reflects the significance of these metabolites in multiple biological processes spanning animals, plants, bacteria, and fungi. We report on analytical methods for measuring TMA and TMAO and attempt to critically synthesize and map the global functions of TMA and TMAO in a systems biology framework.

At the Intersection of Gut Microbiome and Stroke: A Systematic Review of the Literature

Background: Ischemic and hemorrhagic stroke are associated with a high rate of long-term disability and death. Recent investigations focus efforts to better understand how alterations in gut microbiota composition influence clinical outcomes. A key metabolite, trimethylamine N-oxide (TMAO), is linked to multiple inflammatory, vascular, and oxidative pathways. The current biochemical underpinnings of microbial effects on stroke remain largely understudied. The goal of our study is to explore the current literature to explain the interactions between the human gut microbiome and stroke progression, recovery, and outcome. We also provide a descriptive review of TMAO.

Methods: A systematic literature search of published articles between January 1, 1990, and March 22, 2020, was performed on the PubMed database to identify studies addressing the role of the microbiome and TMAO in the pathogenesis and recovery of acute stroke. Our initial investigation focused on human subject studies and was further expanded to include animal studies. Relevant articles were included, regardless of study design. The analysis included reviewers classifying and presenting selected articles by study design and sample size in a chart format.

Results: A total of 222 titles and abstracts were screened. A review of the 68 original human subject articles resulted in the inclusion of 24 studies in this review. To provide further insight into TMAO as a key player, an additional 40 articles were also reviewed and included. Our findings highlighted that alterations in richness and abundance of gut microbes and increased plasma TMAO play an important role in vascular events and outcomes. Our analysis revealed that restoration of a healthy gut, through targeted TMAO-reducing therapies, could provide alternative secondary prevention for at-risk patients.

Discussion: Biochemical interactions between the gut microbiome and inflammation, resulting in metabolic derangements, can affect stroke progression and outcomes. Clinical evidence supports the importance of TMAO in modulating underlying stroke risk factors. Lack of standardization and distinct differences in sample sizes among studies are major limitations.

Gut microbiota, dysbiosis and atrial fibrillation. Arrhythmogenic mechanisms and potential clinical implications

Recent preclinical and observational cohort studies have implicated imbalances in gut microbiota composition as a contributor to atrial fibrillation (AF). The gut microbiota is a complex and dynamic ecosystem containing trillions of microorganisms, which produces bioactive metabolites influencing host health and disease development. In addition to host-specific determinants, lifestyle-related factors such as diet and drugs are important determinants of the gut microbiota composition. In this review, we discuss the evidence suggesting a potential bidirectional association between AF and gut microbiota, identifying gut microbiota-derived metabolites as possible regulators of the AF substrate. We summarize the effect of gut microbiota on the development and progression of AF risk-factors, including heart failure, hypertension, obesity and coronary artery disease. We also discuss the potential antiarrhythmic effects of pharmacological and diet-induced modifications of gut microbiota composition, which may modulate and prevent the progression to AF. Finally, we highlight important gaps in knowledge and areas requiring future investigation. Although data supporting a direct relationship between gut microbiota and AF are very limited at the present time, emerging preclinical and clinical research dealing with mechanistic interactions between gut microbiota and AF is important as it may lead to new insights into AF pathophysiology and the discovery of novel therapeutic targets for AF.

Trimethylamine N-oxide (TMAO): a new attractive target to decrease cardiovascular risk

Cardiovascular disease (CVD) is one of the greatest disease burdens and takes the lives of many each year. There are many risk factors both modifiable and non-modifiable which contribute to the onset and progression of the disease. Trimethylamine N-oxide (TMAO) in recent years has been found to have a correlation with CVD onset. Those with increased levels of the metabolite have a markedly increased risk of future development of cardiometabolic disorders.This literature review aimed to critique past studies undertaken to find a consensus of the significance of the interrelationship between TMAO and cardiovascular risk. A definite link between TMAO levels and a CVD outcome was found. The majority of the literature stated the relationship with evidence; however, there is still some uncertainty as to why and how the correlation occurs. Further study needs to be done to further dissect and understand the relationship between TMAO and CVD risk.

Uremic Toxins in the Progression of Chronic Kidney Disease and Cardiovascular Disease: Mechanisms and Therapeutic Targets

Chronic kidney disease (CKD) is a progressive loss of renal function. The gradual decline in kidney function leads to an accumulation of toxins normally cleared by the kidneys, resulting in uremia. Uremic toxins are classified into three categories: free water-soluble low-molecular-weight solutes, protein-bound solutes, and middle molecules. CKD patients have increased risk of developing cardiovascular disease (CVD), due to an assortment of CKD-specific risk factors. The accumulation of uremic toxins in the circulation and in tissues is associated with the progression of CKD and its co-morbidities, including CVD. Although numerous uremic toxins have been identified to date and many of them are believed to play a role in the progression of CKD and CVD, very few toxins have been extensively studied. The pathophysiological mechanisms of uremic toxins must be investigated further for a better understanding of their roles in disease progression and to develop therapeutic interventions against uremic toxicity. This review discusses the renal and cardiovascular toxicity of uremic toxins indoxyl sulfate, p-cresyl sulfate, hippuric acid, TMAO, ADMA, TNF-α, and IL-6. A focus is also placed on potential therapeutic targets against uremic toxicity.

Use of dietary phytochemicals for inhibition of trimethylamine N-oxide formation

Trimethylamine-N-oxide (TMAO) has been reported as a risk factor for atherosclerosis development, as well as for other cardiovascular disease (CVD) pathologies. The objective of this review is to provide a useful summary on the use of phytochemicals as TMAO-reducing agents. This review discusses the main mechanisms by which TMAO promotes CVD, including the modulation of lipid and bile acid metabolism, and the promotion of endothelial dysfunction and oxidative stress. Current knowledge on the available strategies to reduce TMAO formation are discussed, highlighting the effect and potential of phytochemicals. Overall, phytochemicals (i.e., phenolic compounds or glucosinolates) reduce TMAO formation by modulating gut microbiota composition and/or function, inhibiting host's capacity to metabolize TMA to TMAO, or a combination of both. Perspectives for design of future studies involving phytochemicals as TMAO-reducing agents are discussed. Overall, the information provided by this review outlines the current state of the art of the role of phytochemicals as TMAO reducing agents, providing valuable insight to further advance in this field of study.

Microbiota-Derived Metabolite Trimethylamine N-Oxide Protects Mitochondrial Energy Metabolism and Cardiac Functionality in a Rat Model of Right Ventricle Heart Failure

Aim: Trimethylamine N-oxide (TMAO) is a gut microbiota-derived metabolite synthesized in host organisms from specific food constituents, such as choline, carnitine and betaine. During the last decade, elevated TMAO levels have been proposed as biomarkers to estimate the risk of cardiometabolic diseases. However, there is still no consensus about the role of TMAO in the pathogenesis of cardiovascular disease since regular consumption of TMAO-rich seafood (i.e., a Mediterranean diet) is considered to be beneficial for the primary prevention of cardiovascular events. Therefore, the aim of this study was to investigate the effects of long-term TMAO administration on mitochondrial energy metabolism in an experimental model of right ventricle heart failure. Methods: TMAO was administered to rats at a dose of 120 mg/kg in their drinking water for 10 weeks. Then, a single subcutaneous injection of monocrotaline (MCT) (60 mg/kg) was administered to induce right ventricular dysfunction, and treatment with TMAO was continued (experimental groups: Control; TMAO; MCT; TMAO+MCT). After 4 weeks, right ventricle functionality was assessed by echocardiography, mitochondrial function and heart failure-related gene and protein expression was determined. Results: Compared to the control treatment, the administration of TMAO (120 mg/kg) for 14 weeks increased the TMAO concentration in cardiac tissues up to 14 times. MCT treatment led to impaired mitochondrial function and decreased right ventricular functional parameters. Although TMAO treatment itself decreased mitochondrial fatty acid oxidation-dependent respiration, no effect on cardiac functionality was observed. Long-term TMAO administration prevented MCT-impaired mitochondrial energy metabolism by preserving fatty acid oxidation and subsequently decreasing pyruvate metabolism. In the experimental model of right ventricle heart failure, the impact of TMAO on energy metabolism resulted in a tendency to restore right ventricular function, as indicated by echocardiographic parameters and normalized organ-to-body weight indexes. Similarly, the expression of a marker of heart failure severity, brain natriuretic peptide, was substantially increased in the MCT group but tended to be restored to control levels in the TMAO+MCT group. Conclusion: Elevated TMAO levels preserve mitochondrial energy metabolism and cardiac functionality in an experimental model of right ventricular heart failure, suggesting that under specific conditions TMAO promotes metabolic preconditioning-like effects.

Blood Microbiota and Circulating Microbial Metabolites in Diabetes and Cardiovascular Disease

Diabetes and cardiovascular disease (CVD) have evolved as the leading cause of mortality and morbidity worldwide. In addition to traditional risk factors, recent studies have established that the human microbiota, particularly gut bacteria, plays a role in the development of diabetes and CVD. Although the presence of microbes in blood has been known for centuries, mounting evidence in this metagenomic era provides new insights into the role of the blood microbiota in the pathogenesis of non-infectious diseases such as diabetes and CVD. We highlight the origin and physiology of the blood microbiota and circulating microbial metabolites in relation to the etiology and progression of diabetes and CVD. We also discuss translational perspectives targeting the blood microbiota in the diagnosis and treatment of diabetes and CVD.

Metformin decreases bacterial trimethylamine production and trimethylamine N-oxide levels in db/db mice

The current study aimed to explore whether metformin, the most widely prescribed oral medication for the treatment of type 2 diabetes, alters plasma levels of cardiometabolic disease-related metabolite trimethylamine N-oxide (TMAO) in db/db mice with type 2 diabetes. TMAO plasma concentration was up to 13.2-fold higher in db/db mice when compared to control mice, while in db/db mice fed choline-enriched diet, that mimics meat and dairy product intake, TMAO plasma level was increased 16.8-times. Metformin (250 mg/kg/day) significantly decreased TMAO concentration by up to twofold in both standard and choline-supplemented diet-fed db/db mice plasma. In vitro, metformin significantly decreased the bacterial production rate of trimethylamine (TMA), the precursor of TMAO, from choline up to 3.25-fold in K. pneumoniae and up to 26-fold in P. Mirabilis, while significantly slowing the growth of P. Mirabilis only. Metformin did not affect the expression of genes encoding subunits of bacterial choline-TMA-lyase microcompartment, the activity of the enzyme itself and choline uptake, suggesting that more complex regulation beyond the choline-TMA-lyase is present. To conclude, the TMAO decreasing effect of metformin could be an additional mechanism behind the clinically observed cardiovascular benefits of the drug.

Organic Cation Transporter 1 and 3 Contribute to the High Accumulation of Dehydrocorydaline in the Heart

Dehydrocorydaline (DHC), one of the main active components of Corydalis yanhusuo, is an important remedy for the treatment of coronary heart disease. Our previous study revealed a higher unbound concentration of DHC in the heart than plasma of mice after oral administration of C. yanhusuo extract or DHC, but the underlying uptake mechanism remains unelucidated. In our investigations, we studied the transport mechanism of DHC in transgenic cells, primary neonatal rat cardiomyocytes, and animal experiments. Using quantitative real-time polymerase chain reaction and Western blotting, we found that uptake transporters expressed in the mouse heart include organic cation transporter 1/3 (OCT1/3) and carnitine/organic cation transporter 1/2 (OCTN1/2). The accumulation experiments in transfected cells showed that DHC was a substrate of OCT1 and OCT3, with K _m of 11.29 ± 3.3 and 8.96 ± 3.7 μM, respectively, but not a substrate of OCTN1/2. Additionally, a higher efflux level (1.71-fold of MDCK-mock) of DHC was observed in MDCK-MDR1 cells than in MDCK-mock cells. Therefore, DHC is a weak substrate for MDR1. Studies using primary neonatal rat cardiomyocytes showed that OCT1/3 inhibitors (quinidine, decynium-22, and levo-tetrahydropalmatine) prevented the accumulation of DHC, whereas OCTN2 inhibitors (mildronate and l-carnitine) did not affect its accumulation. Moreover, the coadministration of OCT1/3 inhibitors (levo-tetrahydropalmatine, THP) decreased the concentration of DHC in the mouse heart. Based on these findings, DHC may be accumulated partly by OCT1/3 transporters and excreted by MDR1 in the heart. THP could alter the distribution of DHC in the mouse heart. SIGNIFICANCE STATEMENT: We reported the cardiac transport mechanism of dehydrocorydaline, highly distributed to the heart after oral administration of Corydalis yanhusuo extract or dehydrocorydaline only. Dehydrocorydaline (an OCT1/3 and MDR1 substrate) accumulation in primary cardiomyocytes may be related to the transport activity of OCT1/3. This ability, hampered by selective inhibitors (levo-tetrahydropalmatine, an inhibitor of OCT1/3), causes a nearly 40% reduction in exposure of the heart to dehydrocorydaline. These results suggest that OCT1/3 may contribute to the uptake of dehydrocorydaline in the heart.

Dietary bioactive ingredients to modulate the gut microbiota-derived metabolite TMAO. New opportunities for functional food development

There is a growing body of clinical evidence that supports a strong association between elevated circulating trimethylamine N-oxide (TMAO) levels with increased risk of developing adverse cardiovascular outcomes such as atherosclerosis and thrombosis. TMAO is synthesized through a meta-organismal stepwise process that involves (i) the microbial production of TMA in the gut from dietary precursors and (ii) its subsequent oxidation to TMAO by flavin-containing monooxygenases in the liver. Choline, l-carnitine, betaine, and other TMA-containing compounds are the major dietary precursors of TMA. TMAO can also be absorbed directly from the gastrointestinal tract after the intake of TMAO-rich foods such as fish and shellfish. Thus, diet is an important factor as it provides the nutritional precursors to eventually produce TMAO. A number of studies have attempted to associate circulating TMAO levels with the consumption of diets rich in these foods. On the other hand, there is growing interest for the development of novel food ingredients that reduce either the TMAO-induced damage or the endogenous TMAO levels through the interference with microbiota and host metabolic processes involved in TMAO pathway. Such novel functional food ingredients would offer great opportunities to control circulating TMAO levels or its effects, and potentially contribute to decrease cardiovascular risk. In this review we summarize and discuss current data regarding the effects of TMA precursors-enriched foods or diets on circulating TMAO levels, and recent findings regarding the circulating TMAO-lowering effects of specific foods, food constituents and phytochemicals found in herbs, individually or in extracts, and their potential beneficial effect for cardiovascular health.

Gut microbiota in atherosclerosis: focus on trimethylamine N-oxide

The increasing prevalence of cardiovascular diseases cannot adequately be explained by traditional risk factors. Recently, accumulating evidence has suggested that gut microbiota‐derived numerous metabolites are contributors to atherosclerotic events. Among them, the role of trimethylamine N‐oxide (TMAO) in promoting atherosclerosis has gained attention. TMAO is reported to exert the proatherogenic effects by impacting on the traditional risk factors of atherosclerosis and is associated with high risk of cardiovascular events. Besides that, TMAO is involved in the complex pathological processes of atherosclerotic lesion formation, such as endothelial dysfunction, platelet activation and thrombus generation. In light of these promising findings, TMAO may serve as a potential target for atherosclerosis prevention and treatment, which is conceptually novel, when compared with existing traditional treatments. It is likely that regulating TMAO production and associated gut microbiota may become a promising strategy for the anti‐atherosclerosis therapy.

Meldonium: Pharmacological, toxicological, and analytical aspects

Meldonium is the active molecule from Mildronate® with similar chemical structure to an amino acid, and it is known as (3-(2,2,2-trimethylhydrazine) propionate) (CAS 76144-81-5). This pharmaceutical substance is approved in Eastern Europe for cerebral and myocardial ischemia and has been on the World Doping Association’s banned substances list since January 2016. The goal of this review is to relate the use of meldonium as a doping agent, considering its pharmacological, toxicological, and analytical aspects. This review is based on the scientific literature from digital platforms. The main mechanism of action of meldonium is based on a decrease in l-carnitine levels and increase of peroxisomes activity in the cytosol. Females were more susceptible to the substance in animal experiments for toxicological tests. There is currently no report in the scientific literature about acute or chronic intoxication cases by meldonium in humans. Based on the literature findings, meldonium showed ergogenic effect in animals and human volunteers. For anti-doping analysis, urine is the biological matrix of choice, and dilute-and-shoot is the most common sample treatment in addition to liquid chromatography–mass spectrometry analysis. Other approaches could be used to determine meldonium levels, mainly for screening tests, such as l-carnitine or gamma-butyrobetaine levels.

Trimethylamine N-Oxide Generated by the Gut Microbiota Is Associated with Vascular Inflammation: New Insights into Atherosclerosis

Trimethylamine N-oxide (TMAO) is a biologically active molecule generated by the gut microbiota. Accumulating evidences have indicated a close association between high plasma TMAO levels and the risk of developing atherosclerosis (AS). AS is considered a chronic inflammatory disease initiated by vascular endothelial inflammatory injury. Both observational and experimental studies suggest that TMAO can cause endothelial inflammatory injury. However, a clear mechanistic link between TMAO and vascular inflammation of AS is not yet summarized. In this review, we discuss the association between TMAO and AS and focus on the potential role of TMAO in endothelial inflammatory injury. Finally, the utility of TMAO-targeted therapeutic strategies for the treatment of AS is also analyzed.

Electromembrane Extraction of Highly Polar Compounds: Analysis of Cardiovascular Biomarkers in Plasma

Cardiovascular diseases (CVDs) represent a major concern in today’s society, with more than 17.5 million deaths reported annually worldwide. Recently, five metabolites related to the gut metabolism of phospholipids were identified as promising predictive biomarker candidates for CVD. Validation of those biomarker candidates is crucial for applications to the clinic, showing the need for high-throughput analysis of large numbers of samples. These five compounds, trimethylamine N-oxide (TMAO), choline, betaine, l-carnitine, and deoxy-l-carnitine (4-trimethylammoniobutanoic acid), are highly polar compounds and show poor retention on conventional reversed phase chromatography, which can lead to strong matrix effects when using mass spectrometry detection, especially when high-throughput analysis approaches are used with limited separation of analytes from interferences. In order to reduce the potential matrix effects, we propose a novel fast parallel electromembrane extraction (Pa-EME) method for the analysis of these metabolites in plasma samples. The evaluation of Pa-EME parameters was performed using multi segment injection–capillary electrophoresis–mass spectrometry (MSI-CE-MS). Recoveries up to 100% were achieved, with variability as low as 2%. Overall, this study highlights the necessity of protein precipitation prior to EME for the extraction of highly polar compounds. The developed Pa-EME method was evaluated in terms of concentration range and response function, as well as matrix effects using fast-LC-MS/MS. Finally, the developed workflow was compared to conventional sample pre-treatment, i.e., protein precipitation using methanol, and fast-LC-MS/MS. Data show very strong correlations between both workflows, highlighting the great potential of Pa-EME for high-throughput biological applications.

Modulation of Circulating Trimethylamine N-Oxide Concentrations by Dietary Supplements and Pharmacological Agents: A Systematic Review

Discovery of the association of plasma/serum trimethylamine N-oxide (TMAO) concentrations with atherosclerosis has sparked immense interest in exploring TMAO as a predictor of cardiovascular disease risk. A spectrum of antibiotics and other therapeutic strategies have been employed to test their potential to modulate TMAO concentrations, assuming the gut microbiome to be the key source of TMAO. The aim of this systematic review was to determine whether dietary supplements or pharmacological agents affect TMAO concentrations in adults. Six databases were searched (Medline, EMBASE, CINAHL, Scopus, ProQuest, and PubMed) for randomized and nonrandomized controlled trials. Searches were limited to the English language and to studies in adults. Thirteen eligible trials were identified, including 6 studies on dietary supplements and 7 on pharmacological agents. Whereas intervention studies involving dietary supplements were mostly randomized controlled trials, those involving pharmacological agents appeared opportunistic and varied greatly in study design and duration. Different interventional products were tested, and the studies lacked the consistency to reliably synthesize any evidence for the modifiability of TMAO concentrations by dietary supplements or pharmacological agents. Choline and l-carnitine are conditionally essential nutrients, and carefully designed placebo-controlled randomized trials specifically aimed at reducing the synthesis of microflora-dependent TMAO production from choline-containing precursors by pro- and/or prebiotics, antibiotics, or other pharmaceutical agents may be the way forward for future research.

Implication of Trimethylamine N-Oxide (TMAO) in Disease: Potential Biomarker or New Therapeutic Target

Trimethylamine N-oxide (TMAO) is a molecule generated from choline, betaine, and carnitine via gut microbial metabolism. The plasma level of TMAO is determined by several factors including diet, gut microbial flora, drug administration and liver flavin monooxygenase activity. In humans, recent clinical studies evidence a positive correlation between elevated plasma levels of TMAO and an increased risk for major adverse cardiovascular events. A direct correlation between increased TMAO levels and neurological disorders has been also hypothesized. Several therapeutic strategies are being explored to reduce TMAO levels, including use of oral broad spectrum antibiotics, promoting the growth of bacteria that use TMAO as substrate and the development of target-specific molecules. Despite the accumulating evidence, it is questioned whether TMAO is the mediator of a bystander in the disease process. Thus, it is important to undertake studies to establish the role of TMAO in human health and disease. In this article, we reviewed dietary sources and metabolic pathways of TMAO, as well as screened the studies suggesting possible involvement of TMAO in the etiology of cardiovascular and neurological disorders, underlying the importance of TMAO mediating inflammatory processes. Finally, the potential utility of TMAO as therapeutic target is also analyzed.

Loop diuretics decrease the renal elimination rate and increase the plasma levels of trimethylamine-N-oxide

AIMS

Trimethylamine-N-oxide (TMAO) is a novel cardiovascular risk marker. We explored the association of commonly used cardiovascular medications with TMAO levels in patients and validated the identified associations in mice.

METHODS

Detailed history of drug treatment was recorded in 300 patients with cardiovascular disease without diabetes in an observational, cross-sectional study. Animal study was performed in CD1 mice.

RESULTS

Median plasma TMAO (interquartile range) level was 2.144 (1.570-3.104) μmol l^-1 . Among nine cardiovascular drug groups, the use of loop diuretics (0.510 ± 0.296 in users vs. 0.336 ± 0.272 in nonusers, P = 0.008) and mineralocorticoid receptor antagonists (0.482 ± 0.293 in users vs. 0.334 ± 0.272 in nonusers, P = 0.007) was associated with increased log-TMAO. Acute concomitant administration of furosemide or torasemide with TMAO in mice significantly influenced TMAO pharmacokinetic profile and almost doubled the plasma TMAO area under the curve. Furosemide decreased the TMAO excretion rate by 1.9-fold during the first 30 min after administration and increased TMAO concentrations in kidney, heart and liver, suggesting the interaction of furosemide and TMAO with efflux transporters. The concentrations of TMAO in blood plasma after the administration of the organic anion transporter inhibitor probenecid were not different from those of the control group, suggesting an effect not mediated by organic anion transporters.

CONCLUSIONS

Loop diuretics increased plasma TMAO concentration by decreasing its urinary excretion rate. Loop diuretic use should be considered a potential confounder in TMAO studies.

The Role of Gut Microbiota and Diet on Uremic Retention Solutes Production in the Context of Chronic Kidney Disease

Uremic retention solutes (URS) are associated with cardiovascular complications and poor survival in chronic kidney disease. The better understanding of the origin of a certain number of these toxins enabled the development of new strategies to reduce their production. URS can be classified according to their origins (i.e., host, microbial, or exogenous). The discovery of the fundamental role that the intestinal microbiota plays in the production of many URS has reinstated nutrition at the heart of therapeutics to prevent the accumulation of URS and their deleterious effects. The intestinal microbiota is personalized and is strongly influenced by dietary habits, such as the quantity and the quality of dietary protein and fibers. Herein, this review out lines the role of intestinal microbiota on URS production and the recent discoveries on the effect of diet composition on the microbial balance in the host with a focus on the effect on URS production.

Associations of current diet with plasma and urine TMAO in the KarMeN study: direct and indirect contributions

SCOPE

Knowledge on the influence of current diet on trimethylamine-N-oxide (TMAO) levels in humans is still inconsistent. Thus, we aimed to investigate associations of current diet with urine and plasma TMAO levels and to determine the effect of different foods on TMAO variation.

METHODS AND RESULTS

TMAO concentrations of 297 healthy individuals were assessed using ¹ H-NMR spectroscopy for 24 h urine collection and spot urine, and LC-MS for plasma. Of 35 assessed food groups, those with a correlation of ρ >|0.15| with plasma or urine TMAO levels were further investigated in multivariate linear regression models showing current fish and (red) meat consumption as plausible dietary sources of TMAO. Overall, explained variance of TMAO levels by current diet and co-variables (age, sex, lean body mass, glomerular filtration rate) was small. Associations with urine and plasma concentrations differed depending on the TMAO source. Fish consumption was associated with urine and plasma TMAO concentrations, whereas meat consumption was only associated with TMAO concentrations in plasma. Furthermore, associations of plasma TMAO concentration with fish consumption were two times stronger than with meat consumption.

CONCLUSION

Meat and fish consumption differentially affects TMAO concentrations in body fluids. Only a small fraction of variance is explained by current diet.

The role of trimethylamine N-oxide as a mediator of cardiovascular complications in chronic kidney disease

Patients with chronic kidney disease (CKD) have an enhanced risk of cardiovascular (CV) morbidity and mortality when compared with age- and gender-matched individuals with normal kidney function. Trimethlyamine N-oxide (TMAO) is a gut-derived amine oxide that has been implicated in the causation of CV diseases. Plasma TMAO is cleared by the kidney, and TMAO levels are elevated in CKD. Experimental studies have identified pathogenic mechanisms by which TMAO may contribute to CV disease through dysregulation of lipid metabolism, enhanced macrophage foam cell formation, and platelet dysfunction. Safe and well-tolerated therapeutic interventions such as pre- and probiotics, which modify the gut microbiome, offer the opportunity for interventional studies. This review examines the pathogenicity of TMAO, its value as a biomarker, and its potential as a therapeutic target in the context of CKD.

Trimethylamine N-Oxide, the Microbiome, and Heart and Kidney Disease

Trimethylamine N-oxide (TMAO) is a biologically active molecule and is a putative promoter of chronic diseases including atherosclerosis in humans. Host intestinal bacteria produce its precursor trimethylamine (TMA) from carnitine, choline, or choline-containing compounds. Most of the TMA produced is passively absorbed into portal circulation, and hepatic flavin-dependent monooxygenases (FMOs) efficiently oxidize TMA to TMAO. Both observational and experimental studies suggest a strong positive correlation between increased plasma TMAO concentrations and adverse cardiovascular events, such as myocardial infarction, stroke, and death. However, a clear mechanistic link between TMAO and such diseases is not yet validated. Therefore, it is debated whether increased TMAO concentrations are the cause or result of these diseases. Here, we have tried to review the current understanding of the properties and physiological functions of TMAO, its dietary sources, and its effects on human metabolism. Studies that describe the potential role of TMAO in the etiology of cardiovascular and other diseases are also discussed.

Carnitine and γ-Butyrobetaine Stimulate Elimination of Meldonium due to Competition for OCTN2-mediated Transport

Meldonium (3-(2,2,2-trimethylhydrazinium)propionate) is the most potent clinically used inhibitor of organic cation transporter 2 (OCTN2). Inhibition of OCTN2 leads to a decrease in carnitine and acylcarnitine contents in tissues and energy metabolism optimization-related cardioprotective effects. The recent inclusion of meldonium in the World Anti-Doping Agency List of Prohibited Substances and Methods has raised questions about the pharmacokinetics of meldonium and its unusually long elimination time. Therefore, in this study, the rate of meldonium washout after the end of the treatment was tested with and without administration of carnitine, γ-butyrobetaine (GBB) and furosemide to evaluate the importance of competition for OCTN2 transport in mice. Here, we show that carnitine and GBB administration during the washout period effectively stimulated the elimination of meldonium. GBB induced a more pronounced effect on meldonium elimination than carnitine due to the higher affinity of GBB for OCTN2. The diuretic effect of furosemide did not significantly affect the elimination of meldonium, carnitine and GBB. In conclusion, the competition of meldonium, carnitine and GBB for OCTN2-mediated transport determines the pharmacokinetic properties of meldonium. Thus, due to their affinity for OCTN2, GBB and carnitine but not furosemide stimulated meldonium elimination. During long-term treatment, OCTN2-mediated transport ensures a high muscle content of meldonium, while tissue clearance depends on relatively slow diffusion, thus resulting in the unusually long complete elimination period of meldonium.

Fish oil affects the metabolic process of trimethylamine N-oxide precursor through trimethylamine production and flavin-containing monooxygenase activity in male C57BL/6 mice

Fish oil supplements could affect TMAO metabolic process through gut microbiota and FMOs.

Intestinal Microbiota Metabolism and Atherosclerosis

Objective:

This review aimed to summarize the relationship between intestinal microbiota metabolism and cardiovascular disease (CVD) and to propose a novel CVD therapeutic target.

Data Sources:

This study was based on data obtained from PubMed and EMBASE up to June 30, 2015. Articles were selected using the following search terms: “Intestinal microbiota”, “trimethylamine N-oxide (TMAO)”, “trimethylamine (TMA)”, “cardiovascular”, and “atherosclerosis”.

Study Selection:

Studies were eligible if they present information on intestinal microbiota metabolism and atherosclerosis. Studies on TMA-containing nutrients were also included.

Results:

A new CVD risk factor, TMAO, was recently identified. It has been observed that several TMA-containing compounds may be catabolized by specific intestinal microbiota, resulting in TMA release. TMA is subsequently converted to TMAO in the liver. Several preliminary studies have linked TMAO to CVD, particularly atherosclerosis; however, the details of this relationship remain unclear.

Conclusions:

Intestinal microbiota metabolism is associated with atherosclerosis and may represent a promising therapeutic target with respect to CVD management.

Pharmacological effects of meldonium: Biochemical mechanisms and biomarkers of cardiometabolic activity

Meldonium (mildronate; 3-(2,2,2-trimethylhydrazinium)propionate; THP; MET-88) is a clinically used cardioprotective drug, which mechanism of action is based on the regulation of energy metabolism pathways through l-carnitine lowering effect. l-Carnitine biosynthesis enzyme γ-butyrobetaine hydroxylase and carnitine/organic cation transporter type 2 (OCTN2) are the main known drug targets of meldonium, and through inhibition of these activities meldonium induces adaptive changes in the cellular energy homeostasis. Since l-carnitine is involved in the metabolism of fatty acids, the decline in its levels stimulates glucose metabolism and decreases concentrations of l-carnitine related metabolites, such as long-chain acylcarnitines and trimethylamine-N-oxide. Here, we briefly reviewed the pharmacological effects and mechanisms of meldonium in treatment of heart failure, myocardial infarction, arrhythmia, atherosclerosis and diabetes.

Structure and Function of CutC Choline Lyase from Human Microbiota Bacterium Klebsiella pneumoniae

CutC choline trimethylamine-lyase is an anaerobic bacterial glycyl radical enzyme (GRE) that cleaves choline to produce trimethylamine (TMA) and acetaldehyde. In humans, TMA is produced exclusively by the intestinal microbiota, and its metabolite, trimethylamine oxide, has been associated with a higher risk of cardiovascular diseases. Therefore, information about the three-dimensional structures of TMA-producing enzymes is important for microbiota-targeted drug discovery. We have cloned, expressed, and purified the CutC GRE and the activating enzyme CutD from Klebsiella pneumoniae, a representative of the human microbiota. We have determined the first crystal structures of both the choline-bound and choline-free forms of CutC and have discovered that binding of choline at the ligand-binding site triggers conformational changes in the enzyme structure, a feature that has not been observed for any other characterized GRE.

Methyl-γ-butyrobetaine decreases levels of acylcarnitines and attenuates the development of atherosclerosis

OBJECTIVE

The elevation of the levels of l-carnitine and its fatty acid esters, acylcarnitines, in tissue or plasma has been linked to the development of atherosclerosis. Recently, a potent inhibitor of l-carnitine biosynthesis and transport, methyl-γ-butyrobetaine (methyl-GBB), was discovered. In this study, we evaluated the effects of γ-butyrobetaine (GBB), l-carnitine and methyl-GBB administration on the progression of atherosclerosis.

METHODS

Apolipoprotein E knockout (apoE(-/-)) mice were treated with methyl-GBB, l-carnitine or GBB for 4months. Following the treatment, the amount of atherosclerotic lesions, the number of immune cells in atherosclerotic lesions and the plasma lipid profile were analysed. The l-carnitine and acylcarnitine levels were determined in the aortic tissues of CD-1 outbred mice 2weeks after treatment with methyl-GBB at the dose of 10mg/kg.

RESULTS

Treatment with methyl-GBB decreased the acylcarnitine and l-carnitine levels in the aortic tissues by seventeen- and ten-fold, respectively. Methyl-GBB treatment at a dose of 10mg/kg reduced the size of atherosclerotic plaques by 36%. Neither l-carnitine nor GBB treatment affected the development of atherosclerosis.

CONCLUSIONS

Methyl-GBB administration significantly attenuated the development of atherosclerosis in apoE(-/-)mice. Our results demonstrate that decreasing the acylcarnitine pools can attenuate the development of atherosclerosis.

Acute anti-hyperglycaemic effects of an unripe apple preparation containing phlorizin in healthy volunteers: a preliminary study

BACKGROUND

The health-promoting properties of apples are directly related to the biologically active compounds that they contain, such as polyphenols. The objective of this study was to prepare a low-sugar, fibre- and phlorizin-enriched powder from unripe apples and to gain insight regarding its anti-hyperglycaemic activity in healthy volunteers.

RESULTS

The unripe apples (Malus domestica Borkh.) were collected 30 days after the full bloom day; blanched and pressed to obtain apple pomace which was then processed with a food cutter, oven-dried and milled to prepare apple powder. The concentrations of total sugars, water-soluble pectin and phlorizin in the apple preparation were 153.44 ± 2.46, 27.73 ± 0.51 and 12.61 ± 0.15 g kg(-1), respectively. Acute ingestion of the apple preparation improved glucose metabolism in the oral glucose tolerance test (OGTT) in six healthy volunteers by reducing the postprandial glucose response at 15 to 30 min by approximately two-fold (P < 0.05) and by increasing urinary glucose excretion during the 2- to 4-h interval of the OGTT by five-fold (P < 0.05).

CONCLUSION

The results obtained indicate that the dried and powdered pomace of unripe apples can be used as a health-promoting natural product for the reduction of postprandial glycaemia and to improve the health of patients with diabetes.

Suppression of intestinal microbiota-dependent production of pro-atherogenic trimethylamine N-oxide by shifting L-carnitine microbial degradation

AIMS

Trimethylamine-N-oxide (TMAO) is produced in host liver from trimethylamine (TMA). TMAO and TMA share common dietary quaternary amine precursors, carnitine and choline, which are metabolized by the intestinal microbiota. TMAO recently has been linked to the pathogenesis of atherosclerosis and severity of cardiovascular diseases. We examined the effects of anti-atherosclerotic compound meldonium, an aza-analogue of carnitine bioprecursor gamma-butyrobetaine (GBB), on the availability of TMA and TMAO.

MAIN METHODS

Wistar rats received L-carnitine, GBB or choline alone or in combination with meldonium. Plasma, urine and rat small intestine perfusate samples were assayed for L-carnitine, GBB, choline and TMAO using UPLC-MS/MS. Meldonium effects on TMA production by intestinal bacteria from L-carnitine and choline were tested.

KEY FINDINGS

Treatment with meldonium significantly decreased intestinal microbiota-dependent production of TMA/TMAO from L-carnitine, but not from choline. 24hours after the administration of meldonium, the urinary excretion of TMAO was 3.6 times lower in the combination group than in the L-carnitine-alone group. In addition, the administration of meldonium together with L-carnitine significantly increased GBB concentration in blood plasma and in isolated rat small intestine perfusate. Meldonium did not influence bacterial growth and bacterial uptake of L-carnitine, but TMA production by the intestinal microbiota bacteria K. pneumoniae was significantly decreased.

SIGNIFICANCE

We have shown for the first time that TMA/TMAO production from quaternary amines could be decreased by targeting bacterial TMA-production. In addition, the production of pro-atherogenic TMAO can be suppressed by shifting the microbial degradation pattern of supplemental/dietary quaternary amines.

NEW PATHOGENETIC FACTORS OF ATHEROSCLEROSIS DEVELOPMENT AND POTENTIAL THERAPEUTIC APPROACHES

It has been demonstrated that one of the factors in the pathogenesis of atherosclerosis, with the subsequent development of myocardial infarction (MI), stroke (S), or sudden death (SD), is trimethylaminoxide (TMAO), the end-product of dietary choline, betaine, or carnitine metabolism by intestinal microflora. Simultaneously elevated levels of TMAO and carnitine are associated with a doubled or even tripled risk of MI, S, and SD. Therefore, dietary intake of choline-rich phosphatidylcholine fats and red meats and carnitine-rich dairy is an important risk factor (RF) of atherosclerosis. At the moment, there is no universally accepted therapeutic approach which reduces TMAO and carnitine levels. The only agent which can simultaneously reduce the levels of these two atherosclerosis-associated RFs is a well-known cardio- and cytoprotector Mildronate. Experimental and pilot clinical studies of Mildronate effectiveness in patients with obliterating atherosclerosis suggest the need for further, more detailed clinical trials of Mildronate, for estimation of its efficacy and safety.