Trimethylamine-N-oxide: a link between the gut microbiome, bile acid metabolism, and atherosclerosis

Aged garlic oligosaccharides modulate host metabolism and gut microbiota to alleviate high-fat and high-cholesterol diet-induced atherosclerosis in ApoE-/- mice

Atherosclerosis (AS) is a cardiovascular disease caused by excessive accumulation of lipids in arterial walls. In this study, we developed an AS model in ApoE-/- mice using a high-fat, high-cholesterol diet and investigated the anti-AS mechanism of aged garlic oligosaccharides (AGOs) by focusing on the gut microbiota. Results revealed that AGOs exhibited significant anti-AS effects, reduced trimethylamine N-oxide levels from 349.9 to 189.2 ng/mL, and reduced aortic lipid deposition from 31.7 % to 9.5 %. AGOs significantly increased the levels of short-chain fatty acids in feces, in which acetic, propionic, and butyric acids were increased from 1.580, 0.364, and 0.469 mg/g to 2.233, 0.774, and 0.881 mg/g, respectively. An analysis of the gut microbiota indicated that AGOs restored alpha and beta diversity, decreased the Firmicutes/Bacteroidetes ratio, and promoted the dominance of the genus Akkermansia. A metagenomic analysis revealed that AGOs alleviated AS through the ABC transporter pathway and the lipopolysaccharide biosynthesis pathway.

Gut microbiota-host lipid crosstalk in Alzheimer's disease: implications for disease progression and therapeutics

Trillions of intestinal bacteria in the human body undergo dynamic transformations in response to physiological and pathological changes. Alterations in their composition and metabolites collectively contribute to the progression of Alzheimer's disease. The role of gut microbiota in Alzheimer's disease is diverse and complex, evidence suggests lipid metabolism may be one of the potential pathways. However, the mechanisms that gut microbiota mediate lipid metabolism in Alzheimer's disease pathology remain unclear, necessitating further investigation for clarification. This review highlights the current understanding of how gut microbiota disrupts lipid metabolism and discusses the implications of these discoveries in guiding strategies for the prevention or treatment of Alzheimer's disease based on existing data.

Metabolomic and genomic insights into TMA degradation by a novel halotolerant strain - Paracoccus sp. PS1

Trimethylamine N-oxide (TMAO) is a gut metabolite that acts as a biomarker for chronic diseases, and is generated by the oxidation of trimethylamine (TMA) produced by gut microflora. Since, microbial degradation of TMA is predicted to be used to restrict the production of TMAO, we aimed to isolate bacterial strains that could effectively degrade TMA before being oxidized to TMAO. As marine fish is considered to have a rich content of TMAO, we have isolated TMA degrading isolates from fish skin. Out of the fourteen isolates, depending on their rapid TMA utilization capability in mineral salt medium supplemented with TMA as a sole carbon and nitrogen source, isolate PS1 was selected as our desired isolate. Its TMA degrading capacity was further confirmed through spectrophotometric, Electrospray Ionization Time-of-Flight Mass Spectrometry (ESI TOF-MS) and High performance liquid chromatography (HPLC) analysis and in silico analysis of whole genome (WG) gave further insights of protein into its TMA degradation pathways. PS1 was taxonomically identified as Paracoccus sp. based on its 16S rRNA and whole genome sequence analysis. As PS1 possesses the enzymes required for degradation of TMA, clinical use of this isolate has the potential to reduce TMAO generation in the human gut.

Cardiovascular risk of dietary trimethylamine oxide precursors and the therapeutic potential of resveratrol and its derivatives

Overall diet, lifestyle choices, genetic predisposition, and other underlying health conditions may contribute to higher trimethylamine N-oxide (TMAO) levels and increased cardiovascular risk. This review explores the potential therapeutic ability of RSV to protect against cardiovascular diseases (CVD) and affect TMAO levels. This review considers recent studies on the association of TMAO with CVD. It also examines the sources, mechanisms, and metabolism of TMAO along with TMAO-induced cardiovascular events. Plant polyphenolic compounds, including resveratrol (RSV), and their cardioprotective mechanism of regulating TMAO levels and modifying gut microbiota are also discussed here. RSV's salient features and bioactive properties in reducing CVD have been evaluated. The close relationship between TMAO and CVD is clearly understood from currently available data, making it a potent biomarker for CVD. Precise investigation, including clinical trials, must be performed to understand RSV's mechanism, dose, effects, and derivatives as a cardioprotectant agent.

Prospect of research on anti-atherosclerosis effect of main components of traditional Chinese medicine Yiqi Huoxue Huatan recipe through gut microbiota: A review

The incidence and mortality rates of cardiovascular diseases are on the rise globally, posing a severe threat to human health. Atherosclerosis (AS) is considered a multi-factorial inflammatory disease and the main pathological basis of cardiovascular and cerebrovascular diseases, as well as the leading cause of death. Dysbiosis of the gut microbiota can induce and exacerbate inflammatory reactions, accelerate metabolic disorders and immune function decline, and affect the progression and prognosis of AS-related diseases. The Chinese herbal medicine clinicians frequently utilize Yiqi Huoxue Huatan recipe, an effective therapeutic approach for the management of AS. This article reviews the correlation between the main components of Yiqi Huoxue Huatan recipe and the gut microbiota and AS to provide new directions and a theoretical basis for the prevention and treatment of AS.

Gut microbiota metabolites, redox status, and the related regulatory effects of probiotics

Oxidative stress is a state of imbalance between oxidation and antioxidation. It is caused by excess levels of free radicals and leads to the damage of DNA, proteins, and lipids. The crucial role of gut microbiota in regulating oxidative stress has been widely demonstrated. Studies have suggested that the redox regulatory effects of gut microbiota are related to gut microbiota metabolites, including fatty acids, lipopolysaccharides, tryptophan metabolites, trimethylamine-N-oxide and polyphenolic metabolites. In recent years, the potential benefits of probiotics have been gaining increasing scientific interest owing to their ability to modulate gut microbiota and oxidative stress. In this review, we summarise the adverse health effects of oxidative stress and discuss the role of the gut microbiota and its metabolites in redox regulation. Based on the influence of gut microbiota metabolites, the roles of probiotics in preventing oxidative stress are highlighted.

Role of glycolysis in diabetic atherosclerosis

Diabetes mellitus is a kind of typical metabolic disorder characterized by elevated blood sugar levels. Atherosclerosis (AS) is one of the most common complications of diabetes. Modern lifestyles and trends that promote overconsumption and unhealthy practices have contributed to an increase in the annual incidence of diabetic AS worldwide, which has created a heavy burden on society. Several studies have shown the significant effects of glycolysis-related changes on the occurrence and development of diabetic AS, which may serve as novel thera-peutic targets for diabetic AS in the future. Glycolysis is an important metabolic pathway that generates energy in various cells of the blood vessel wall. In particular, it plays a vital role in the physiological and pathological activities of the three important cells, Endothelial cells, macrophages and vascular smooth muscle cells. There are lots of similar mechanisms underlying diabetic and common AS, the former is more complex. In this article, we describe the role and mechanism underlying glycolysis in diabetic AS, as well as the therapeutic targets, such as trained immunity, microRNAs, gut microbiota, and associated drugs, with the aim to provide some new perspectives and potentially feasible programs for the treatment of diabetic AS in the foreseeable future.

Might Gut Microbiota Be a Target for a Personalized Therapeutic Approach in Patients Affected by Atherosclerosis Disease?

In recent years, the increasing number of studies on the relationship between the gut microbiota and atherosclerosis have led to significant interest in this subject. The gut microbiota, its metabolites (metabolome), such as TMAO, and gut dysbiosis play an important role in the development of atherosclerosis. Furthermore, inflammation, originating from the intestinal tract, adds yet another mechanism by which the human ecosystem is disrupted, resulting in the manifestation of metabolic diseases and, by extension, cardiovascular diseases. The scientific community must understand and elucidate these mechanisms in depth, to gain a better understanding of the relationship between atherosclerosis and the gut microbiome and to promote the development of new therapeutic targets in the coming years. This review aims to present the knowledge acquired so far, to trigger others to further investigate this intriguing topic.

Role of Gut Microbiome in Atherosclerosis: Molecular and Therapeutic Aspects

Atherosclerosis is one of the most relevant and prevalent cardiovascular diseases of our time. It is one of the pathological entities that increases the morbidity and mortality index in the adult population. Pathophysiological connections have been observed between atherosclerosis and the gut microbiome (GM), represented by a group of microorganisms that are present in the gut. These microorganisms are vital for metabolic homeostasis in humans. Recently, direct and indirect mechanisms through which GM can affect the development of atherosclerosis have been studied. This has led to research into the possible modulation of GM and metabolites as a new target in the prevention and treatment of atherosclerosis. The goal of this review is to analyze the physiopathological mechanisms linking GM and atherosclerosis that have been described so far. We also aim to summarize the recent studies that propose GM as a potential target in atherosclerosis management.

Effects of intestinal bacteria on cardiovascular disease

In the long process of human evolution, the Intestinal Bacteria has become intimately related to human health, producing many metabolites in the intestines that can affect cardiovascular disease. Today, the incidence of cardiovascular disease is rising, its treatment is becoming increasingly important, and new therapeutic targets are needed. Here we describe the effects of trimethylamine oxide (TMAO), lipid metabolism, phenolic compounds, indole sulfate (IS), oleuropein (OL), and hydroxytyrosol (HT) on atherosclerosis, heart failure, hypertension, and other cardiovascular diseases, as well as their mechanism of action. This study provides new ideas, new methods, and new directions for the treatment of cardiovascular disease.

The Gut Microbiome Composition Is Altered in Long-standing Type 1 Diabetes and Associates With Glycemic Control and Disease-Related Complications

OBJECTIVE

People with type 1 diabetes are at risk for developing micro- and macrovascular complications. Little is known about the gut microbiome in long-standing type 1 diabetes. We explored differences in the gut microbiome of participants with type 1 diabetes compared with healthy control subjects and associated the gut microbiome with diabetes-related complications.

RESEARCH DESIGN AND METHODS

Microbiome data of 238 participants with type 1 diabetes with an average disease duration of 28 ± 15 years were compared with 2,937 age-, sex-, and BMI-matched individuals. Clinical characteristics and fecal samples were collected, and metagenomic shotgun sequencing was performed. Microbial taxonomy was associated with type 1 diabetes-related characteristics and vascular complications.

RESULTS

No significant difference in the α-diversity of the gut microbiome was found between participants with type 1 diabetes and healthy control subjects. However, 43 bacterial taxa were significantly depleted in type 1 diabetes, while 37 bacterial taxa were significantly enriched. HbA1c and disease duration explained a significant part of the variation in the gut microbiome (R2 > 0.008, false discovery rate [FDR] <0.05), and HbA1c was significantly associated with the abundance of several microbial species. Additionally, both micro- and macrovascular complications explained a significant part of the variation in the gut microbiome (R2 > 0.0075, FDR < 0.05). Nephropathy was strongly associated with several microbial species. Macrovascular complications displayed similar associations with nephropathy.

CONCLUSIONS

Our data show that the gut microbiome is altered in people with (long-standing) type 1 diabetes and is associated with glycemic control and diabetes-related complications. As a result of the cross-sectional design, the causality of these relationships remains to be determined.

Dietary titanium dioxide particles (E171) promote diet-induced atherosclerosis through reprogramming gut microbiota-mediated choline metabolism in APOE-/- mice

Food-grade titanium dioxide (E171) has been reported to induce changes in some intestinal metabolites related to development of atherosclerosis (AS). However, little is known about the effects of chronic dietary intake of E171 on AS development, particularly in AS-prone populations with high-choline western diet (HCD). Herein, we disclosed that E171 obviously exacerbated HCD-induced AS through increasing production of trimethylamine (TMA) and pro-atherogenic trimethylamine-N-oxide (TMAO) via remodeling gut microbiota structure in APOE^-/- mice. Oral administration of 40 mg/kg E171 daily for 4 months significantly increased the atherosclerotic lesion area, especially in the HCD group. Mechanistic studies revealed that E171 induced much more TMAO production by increasing the gut microbial expression of choline TMA lyases (CutC/D), which converted dietary choline to TMA by a glycyl radical reaction. The 16S rDNA sequencing analysis demonstrated that bacterial strains expressing CutC/D were enriched by E171 in HCD-fed mice. In contrast, gut microbiota depletion eliminated the impact of E171 on choline/TMA/TMAO pathway and AS progression, indicating gut flora shifts were responsible for the exacerbation effects of E171 ingestion on HCD-induced AS. All the results emphasized the alarming role of E171 on AS progression and stated the importance of reevaluating the impact of food additives on the development of chronic diseases.

Interactions between gut microbiota and berberine, a necessary procedure to understand the mechanisms of berberine

Berberine (BBR), an isoquinoline alkaloid, has been found in many plants, such as Coptis chinensis Franch and Phellodendron chinense Schneid. Although BBR has a wide spectrum of pharmacological effects, its oral bioavailability is extremely low. In recent years, gut microbiota has emerged as a cynosure to understand the mechanisms of action of herbal compounds. Numerous studies have demonstrated that due to its low bioavailability, BBR can interact with the gut microbiota, thereby exhibiting altered pharmacological effects. However, no systematic and comprehensive review has summarized these interactions and their corresponding influences on pharmacological effects. Here, we describe the direct interactive relationships between BBR and gut microbiota, including regulation of gut microbiota composition and metabolism by BBR and metabolization of BBR by gut microbiota. In addition, the complex interactions between gut microbiota and BBR as well as the side effects and personalized use of BBR are discussed. Furthermore, we provide our viewpoint on future research directions regarding BBR and gut microbiota. This review not only helps to explain the mechanisms underlying BBR activity but also provides support for the rational use of BBR in clinical practice.

Trimethylamine N-Oxide Reduces the Susceptibility of Escherichia coli to Multiple Antibiotics

Trimethylamine N-oxide (TMAO), an important intestinal flora-derived metabolite, plays a role in the development of cardiovascular disease and tumor immunity. Here, we determined the minimum inhibitory concentration (MIC) of antibiotics against Escherichia coli under gradient concentrations of TMAO and performed a bacterial killing analysis. Overall, TMAO (in the range of 10 ~ 100 mM) increased the MIC of quinolones, aminoglycosides, and β-lactams in a concentration-dependent manner, and increased the lethal dose of antibiotics against E. coli. It implies that TMAO is a potential risk for failure of anti-infective therapy, and presents a case for the relationship between intestinal flora-derived metabolites and antibiotic resistance. Further data demonstrated that the inhibition of antibiotic efficacy by TMAO is independent of the downstream metabolic processes of TMAO and the typical bacterial resistance mechanisms (mar motif and efflux pump). Interestingly, TMAO protects E. coli from high-protein denaturant (urea) stress and improves the viability of bacteria following treatment with two disinfectants (ethanol and hydrogen peroxide) that mediate protein denaturation by chemical action or oxidation. Since antibiotics can induce protein inactivation directly or indirectly, our work suggests that disruption of protein homeostasis may be a common pathway for different stress-mediated bacterial growth inhibition/cell death. In addition, we further discuss this possibility, which provides a different perspective to address the global public health problem of antibiotic resistance.

The Role of Bile Acids in Cardiovascular Diseases: from Mechanisms to Clinical Implications

Bile acids (BAs), key regulators in the metabolic network, are not only involved in lipid digestion and absorption but also serve as potential therapeutic targets for metabolic disorders. Studies have shown that cardiac dysfunction is associated with abnormal BA metabolic pathways. As ligands for several nuclear receptors and membrane receptors, BAs systematically regulate the homeostasis of metabolism and participate in cardiovascular diseases (CVDs), such as myocardial infarction, diabetic cardiomyopathy, atherosclerosis, arrhythmia, and heart failure. However, the molecular mechanism by which BAs trigger CVDs remains controversial. Therefore, the regulation of BA signal transduction by modulating the synthesis and composition of BAs is an interesting and novel direction for potential therapies for CVDs. Here, we mainly summarized the metabolism of BAs and their role in cardiomyocytes and noncardiomyocytes in CVDs. Moreover, we comprehensively discussed the clinical prospects of BAs in CVDs and analyzed the clinical diagnostic and application value of BAs. The latest development prospects of BAs in the field of new drug development are also prospected. We aimed to elucidate the underlying mechanism of BAs treatment in CVDs, and the relationship between BAs and CVDs may provide new avenues for the prevention and treatment of these diseases.

Over-feeding the gut microbiome: A scoping review on health implications and therapeutic perspectives

The human gut microbiome has gained increasing attention over the past two decades. Several findings have shown that this complex and dynamic microbial ecosystem can contribute to the maintenance of host health or, when subject to imbalances, to the pathogenesis of various enteric and non-enteric diseases. This scoping review summarizes the current knowledge on how the gut microbiota and microbially-derived compounds affect host metabolism, especially in the context of obesity and related disorders. Examples of microbiome-based targeted intervention strategies that aim to restore and maintain an eubiotic layout are then discussed. Adjuvant therapeutic interventions to alleviate obesity and associated comorbidities are traditionally based on diet modulation and the supplementation of prebiotics, probiotics and synbiotics. However, these approaches have shown only moderate ability to induce sustained changes in the gut microbial ecosystem, making the development of innovative and tailored microbiome-based intervention strategies of utmost importance in clinical practice. In this regard, the administration of next-generation probiotics and engineered microbiomes has shown promising results, together with more radical intervention strategies based on the replacement of the dysbiotic ecosystem by means of fecal microbiota transplantation from healthy donors or with the introduction of synthetic communities specifically designed to achieve the desired therapeutic outcome. Finally, we provide a perspective for future translational investigations through the implementation of bioinformatics approaches, including machine and deep learning, to predict health risks and therapeutic outcomes.

The Relationship among Physical Activity, Intestinal Flora, and Cardiovascular Disease

Cardiovascular diseases (CVDs), which are associated with high morbidity and mortality worldwide, include atherosclerosis (AS), hypertension, heart failure (HF), atrial fibrillation, and myocardial fibrosis. CVDs are influenced by the diversity, distribution, and metabolites of intestinal microflora, and their risk can be reduced through physical activity (PA) such as regular exercise. PA benefits the metabolic changes that occur in the gut microbiota (GM). The major metabolites of the GM influence pathogenesis of CVDs through various pathways. However, the relationship between PA and GM is less well understood. In this review, we discuss the impacts of different types of PA on intestinal microflora including the diversity, distribution, metabolites, and intestinal barrier function including intestinal permeability, with a focus on the mechanisms by which PA affects GM. We also discuss how GM influences CVDs. Finally, we summarize current research and knowledge on the effects of PA on CVD via regulation of the GM and intestinal function. More understanding of relevant relationship between PA and GM may provide hope for the prevention or treatment of CVDs. Furthermore, a better understanding of regulation of the GM and intestinal function may lead to novel diagnostic and therapeutic strategies, improving the clinical care of CVD patients.

TMAO promotes apoptosis and oxidative stress of pancreatic acinar cells by mediating IRE1α-XBP-1 pathway

BACKGROUND

Acute pancreatitis caused by hyperlipidemia is a severe life-threatening condition. Therefore, it is urgent to develop new therapeutic methods to treat this disease.

METHODS

Cell viability was determined by the Cell Counting Kit-8 (CCK-8) assay. Western blotting (WB) was used to detect the expression levels of apoptotic and endoribonuclease inositol-requiring enzyme 1α (IRE1α)/X-box binding protein 1 (XBP-1) pathway-associated proteins. The induction of cell apoptosis was determined using flow cytometry. The expression levels of the oxidative stress indicators were measured by an enzyme-linked immunosorbent assay.

RESULTS

WB analysis and the CCK-8 assay demonstrated that trimethylamine-N-oxide (TMAO) decreased cell viability and facilitated apoptosis of MPC-83 cells in a dose-dependent manner. Furthermore, the induction of oxidative stress was assessed by evaluating the levels of specific markers, including hydrogen peroxide, reactive oxygen species, nitric oxide, and superoxide dismutase. The levels of the aforementioned markers were increased in the TMAO-treated group. Subsequently, the IRE1α/XBP-1 pathway-associated proteins were analyzed by WB analysis and the data demonstrated that the regulatory effects of TMAO on MPC-83 cells were meditated by the IRE1α/XBP-1 signaling pathway. Subsequently, rescue experiments were performed to further assess the effects of TMAO.

CONCLUSION

The present study provides evidence on the application of TMAO as a potential diagnostic and therapeutic strategy for the therapeutic intervention of hyperlipidemic acute pancreatitis.

Dysbiosis, Host Metabolism, and Non-communicable Diseases: Trialogue in the Inborn Errors of Metabolism

Inborn errors of metabolism (IEMs) represent a complex system model, in need of a shift of approach exploring the main factors mediating the regulation of the system, internal or external and overcoming the traditional concept of biochemical and genetic defects. In this context, among the established factors influencing the metabolic flux, i.e., diet, lifestyle, antibiotics, xenobiotics, infectious agents, also the individual gut microbiota should be considered. A healthy gut microbiota contributes in maintaining human health by providing unique metabolic functions to the human host. Many patients with IEMs are on special diets, the main treatment for these diseases. Hence, IEMs represent a good model to evaluate how specific dietary patterns, in terms of macronutrients composition and quality of nutrients, can be related to a characteristic microbiota associated with a specific clinical phenotype (“enterophenotype”). In the present review, we aim at reporting the possible links existing between dysbiosis, a condition reported in IEMs patients, and a pro-inflammatory status, through an altered “gut-liver” cross-talk network and a major oxidative stress, with a repercussion on the health status of the patient, increasing the risk of non-communicable diseases (NCDs). On this basis, more attention should be paid to the nutritional status assessment and the clinical and biochemical signs of possible onset of comorbidities, with the goal of improving the long-term wellbeing in IEMs. A balanced intestinal ecosystem has been shown to positively contribute to patient health and its perturbation may influence the clinical spectrum of individuals with IEMs. For this, reaching eubiosis through the improvement of the quality of dietary products and mixtures, the use of pre-, pro- and postbiotics, could represent both a preventive and therapeutic strategy in these complex diseases.

Modifications in the Intestinal Functionality, Morphology and Microbiome Following Intra-Amniotic Administration (Gallus gallus) of Grape (Vitis vinifera) Stilbenes (Resveratrol and Pterostilbene)

This efficacy trial evaluated the effects of two polyphenolic stilbenes, resveratrol and pterostilbene, mostly found in grapes, on the brush border membrane functionality, morphology and gut microbiome. This study applied the validated Gallus gallus intra-amniotic approach to investigate the effects of stilbene administration versus the controls. Three treatment groups (5% resveratrol; 5% pterostilbene; and synergistic: 4.75% resveratrol and 0.25% pterostilbene) and three controls (18 MΩ H₂O; no injection; 5% inulin) were employed. We observed beneficial morphological changes, specifically an increase in the villus length, diameter, depth of crypts and goblet cell diameter in the pterostilbene and synergistic groups, with concomitant increases in the serum iron and zinc concentrations. Further, the alterations in gene expression of the mineral metabolism proteins and pro-inflammatory cytokines indicate a potential improvement in gut health and mineral bioavailability. The cecal microbiota was analyzed using 16S rRNA sequencing. A lower α-diversity was observed in the synergistic group compared with the other treatment groups. However, beneficial compositional and functional alterations in the gut microbiome were detected. Several key microbial metabolic pathways were differentially enriched in the pterostilbene treatment group. These observations demonstrate a significant bacterial–host interaction that contributed to enhancements in intestinal functionality, morphology and physiological status. Our data demonstrate a novel understanding of the nutritional benefits of dietary stilbenes and their effects on intestinal functionality, morphology and gut microbiota in vivo.

Intermittent Hypoxia and Hypercapnia Alter Diurnal Rhythms of Luminal Gut Microbiome and Metabolome

Obstructive sleep apnea (OSA), characterized by intermittent hypoxia and hypercapnia (IHC), affects the composition of the gut microbiome and metabolome. The gut microbiome has diurnal oscillations that play a crucial role in regulating circadian and overall metabolic homeostasis. Thus, we hypothesized that IHC adversely alters the gut luminal dynamics of key microbial families and metabolites. The objective of this study was to determine the diurnal dynamics of the fecal microbiome and metabolome of Apoe-/- mice after a week of IHC exposure. Individually housed, 10-week-old Apoe-/- mice on an atherogenic diet were split into two groups. One group was exposed to daily IHC conditions for 10 h (Zeitgeber time 2 [ZT2] to ZT12), while the other was maintained in room air. Six days after the initiation of the IHC conditions, fecal samples were collected every 4 h for 24 h (6 time points). We performed 16S rRNA gene amplicon sequencing and untargeted liquid chromatography-mass spectrometry (LC-MS) to assess changes in the microbiome and metabolome. IHC induced global changes in the cyclical dynamics of the gut microbiome and metabolome. Ruminococcaceae, Lachnospiraceae, S24-7, and Verrucomicrobiaceae had the greatest shifts in their diurnal oscillations. In the metabolome, bile acids, glycerolipids (phosphocholines and phosphoethanolamines), and acylcarnitines were greatly affected. Multi-omic analysis of these results demonstrated that Ruminococcaceae and tauro-β-muricholic acid (TβMCA) cooccur and are associated with IHC conditions and that Coriobacteriaceae and chenodeoxycholic acid (CDCA) cooccur and are associated with control conditions. IHC significantly change the diurnal dynamics of the fecal microbiome and metabolome, increasing members and metabolites that are proinflammatory and proatherogenic while decreasing protective ones. IMPORTANCE People with obstructive sleep apnea are at a higher risk of high blood pressure, type 2 diabetes, cardiac arrhythmias, stroke, and sudden cardiac death. We wanted to understand whether the gut microbiome changes induced by obstructive sleep apnea could potentially explain some of these medical problems. By collecting stool from a mouse model of this disease at multiple time points during the day, we studied how obstructive sleep apnea changed the day-night patterns of microbes and metabolites of the gut. Since the oscillations of the gut microbiome play a crucial role in regulating metabolism, changes in these oscillations can explain why these patients can develop so many metabolic problems. We found changes in microbial families and metabolites that regulate many metabolic pathways contributing to the increased risk for heart disease seen in patients with obstructive sleep apnea.

Reduction of TMAO level enhances the stability of carotid atherosclerotic plaque through promoting macrophage M2 polarization and efferocytosis

It has been demonstrated that trimethylamine N-oxide (TMAO) serves as a driver of atherosclerosis, suggesting that reduction of TMAO level might be a potent method to prevent the progression of atherosclerosis. Herein, we explored the role of TMAO in the stability of carotid atherosclerotic plaques and disclosed the underlying mechanisms. The unstable carotid artery plaque models were established in C57/BL6 mice. L-carnitine (LCA) and methimazole (MMI) administration were applied to increase and reduce TMAO levels. Hematoxylin and eosin (H&E) staining, Sirius red, Perl's staining, Masson trichrome staining and immunohistochemical staining with CD68 staining were used for histopathology analysis of the carotid artery plaque. M1 and M2 macrophagocyte markers were assessed by RT-PCR to determine the polarization of RAW264.7 cells. MMI administration for 2 weeks significantly decreased the plaque area, increased the thickness of the fibrous cap and reduced the size of the necrotic lipid cores, whereas 5-week of administration of MMI induced intraplate hemorrhage. LCA treatment further deteriorated the carotid atherosclerotic plaque but with no significant difference. In mechanism, we found that TMAO treatment impaired the M2 polarization and efferocytosis of RAW264.7 cells with no obvious effect on the M1 polarization. In conclusion, the present study demonstrated that TMAO reduction enhanced the stability of carotid atherosclerotic plaque through promoting macrophage M2 polarization and efferocytosis.

Co-exposure to inorganic arsenic and fluoride prominently disrupts gut microbiota equilibrium and induces adverse cardiovascular effects in offspring rats

Co-exposure to inorganic arsenic (iAs) and fluoride (F^-) and their collective actions on cardiovascular systems have been recognized as a global public health concern. Emerging studies suggest an association between the perturbation of gut bacterial microbiota and adverse cardiovascular effects (CVEs), both of which are the consequence of iAs and F^- exposure in human and experimental animals. The aim of this study was to fill the gap of understanding the relationship among co-exposure to iAs and F^-, gut microbiota perturbation, and adverse CVEs. We systematically assessed cardiac morphology and functions (blood pressure, echocardiogram, and electrocardiogram), and generated gut microbiota profiles using 16S rRNA gene sequencing on rats exposed to iAs (50 mg/L NaAsO₂), F^- (100 mg/L NaF) or combined iAs and F^- (50 mg/L NaAsO₂ + 100 mg/L NaF), in utero and during early postnatal periods (postnatal day 90). Correlation analysis was then performed to examine relationship between significantly altered microbiota and cardiac performance indices. Our results showed that co-exposure to iAs and F^- resulted in more prominent effects in CVEs and perturbation of gut microbiota profiles, compared to iAs or F^- treatment alone. Furthermore, nine bacterial genera (Adlercreutzia, Clostridium sensu stricto 1, Coprococcus 3, Romboutsia, [Bacteroides] Pectinophilus group, Lachnospiraceae NC2004 group, Desulfovibrio, and two unidentified genera in Muribaculaceae and Ruminococcaceae family), which differed significantly in relative abundance between control and iAs and F^- co-exposure group, were strongly correlated with the higher risk of CVEs (correlation coefficient = 0.70-0.88, p < 0.05). Collectively, these results suggest that co-exposure to iAs and F^- poses a higher risk of CVEs, and the part of the mode of action is potentially through inducing gut microbiota disruption, and the strong correlations between them indicate a high potential for the development of novel microbiome-based biomarkers of iAs and/or F^- associated CVEs.

The Relationship of Large-Artery Atherothrombotic Stroke with Plasma Trimethylamine N-Oxide Level and Blood Lipid-Related Indices: A Cross-Sectional Comparative Study

Objective

The role of trimethylamine N-oxide (TMAO) in cardiovascular diseases has been highlighted. Nevertheless, the associations of large-artery atherosclerotic (LAA) stroke with TMAO and blood lipid-related indices are little investigated.

Methods

A cross-sectional comparative study was performed on 50 patients with LAA stroke and 50 healthy controls. Basic demographic data, common vascular risk factors, and blood lipid-related indices were collected. Plasma TMAO was detected through liquid chromatography tandem mass spectrometry. Multivariable unconditional logistic regression analyses were run to assess the associations of LAA stroke with plasma TMAO level and blood lipid-related indices. The area under the curve (AUC) of the receiver operating characteristic (ROC) was computed to assess the diagnostic performance of plasma TMAO level and blood lipid-related indices for LAA stroke.

Results

Compared with healthy controls, the elevated plasma TMAO level (odds ratio [OR], 7.03; 95% confidence interval [CI], 2.86, 17.25; p < 0.01) and Apo-B (OR, 1.74; 95% CI, 1.06, 2.85; p = 0.03) were observed in LAA stroke patients, while lower Apo-A1 (OR, 0.56; 95% CI, 0.34, 0.91; p = 0.02), Apo-A1 to Apo-B ratio (OR, 0.29; 95% CI, 0.15, 0.56; p < 0.01), and HDL-C (OR, 0.56; 95% CI, 0.35, 0.91; p = 0.02) were found in LAA stroke patients after adjusted for age and gender. Moreover, plasma TMAO (AUC, 0.89; 95% CI, 0.83, 0.95), Apo-A1 (AUC, 0.81; 95% CI, 0.72, 0.89), Apo-B (AUC, 0.81; 95% CI, 0.73, 0.90), Apo-A1 to Apo-B ratio (AUC, 0.85; 95% CI, 0.78, 0.93), and HDL-C (AUC, 0.81; 95% CI, 0.72, 0.89) showed good diagnostic values for LAA stroke in adjusted models.

Conclusions

The plasma TMAO level, Apo-A1, Apo-B, and HDL-C are important biomarkers for LAA stroke patients.

Metabolomics Insights into Oleate-Induced Disorders of Phospholipid Metabolism in Macrophages

BACKGROUND

Diet-induced disordered phospholipid metabolism and disturbed macrophage metabolism contribute to the pathogenesis of metabolic diseases. However, the effects of oleate, a main dietary fatty acid, on macrophage phospholipid metabolism are unclear.

OBJECTIVES

We aimed to discover oleate-induced disorders of macrophage phospholipid metabolism and potential therapeutic targets for treating diet-related metabolic diseases.

METHODS

RAW 264.7 cells were exposed to 65 μg oleate/mL, within the blood concentration range of humans and mice, to trigger disorders of phospholipid metabolism. Meanwhile, WY-14643 and pioglitazone, 2 drugs widely used for treating metabolic diseases, were employed to prevent oleate-induced disorders of macrophage phospholipid metabolism. Subsequently, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry was used to discover relevant metabolic disorders and potential therapeutic targets.

RESULTS

We showed that 196 metabolites involved in phospholipid metabolism were altered upon oleate treatment and interventions of WY-14643 and pioglitazone (P < 0.05, 2-tailed Mann-Whitney U test). Notably, most lysophospholipids were decreased, whereas most phospholipids were increased in oleate-treated macrophages. Phosphatidylethanolamines accumulated most among phospholipids, and their acyl chain polyunsaturation increased in oleate-treated macrophages. Additionally, saturated fatty acids were decreased, whereas polyunsaturated fatty acids were increased in oleate-treated macrophages. Furthermore, changes in phosphatidylglycerols, phosphatidylinositols, cardiolipins, phosphatidates, lysophosphatidylglycerols, and acylcarnitines in oleate-treated macrophages could be attenuated or even abolished by WY-14643 and/or pioglitazone treatment.

CONCLUSIONS

Oleate induced accumulation of various phospholipids, increased acyl chain polyunsaturation of phosphatidylethanolamines, and decreased lysophospholipids in RAW 264.7 macrophages. This study suggests macrophage phospholipid and fatty acid metabolism as potential therapeutic targets for intervening diet-related metabolic diseases.

Association between Gut Microbial Diversity and Carotid Intima-Media Thickness

Background and Objectives: There is an increasing focus on the effect of the gut microbiome on developing atherosclerosis, but there is still no unified standpoint. We aimed to find associations between intestinal microbiome diversity and a marker of subclinical atherosclerosis, the carotid intima-media thickness (IMT). Materials and Methods: Recruited from the Hungarian Twin Registry, 108 monozygotic (MZ) twins (mean age 52.4 ± 14.1 years, 58% female) underwent a comprehensive carotid ultrasound examination (Samsung RS85). Of the 108 MZ twins, 14 pairs (mean age 65 ± 6.4 years, 71% female) discordant for carotid IMT were selected to undergo a stool sample collection. A special stool sampling container was mailed and received from each participant. After DNA extraction, library construction was performed specifically for the V3–V4 hypervariable region of microbial 16S rRNA. Next, the microbiome composition of the samples was determined using Kraken software. Two hypotheses were tested with the exact permutation test: (1) in the group with normal IMT, the Shannon index of the phyla is higher; and (2) the Firmicutes/Bacteroidetes ratio is greater in the group with high IMT values. Furthermore, the abundance of different bacterial strains present at higher and normal IMT was also explored. Statistical analysis was carried out using R software. Results: Increased Firmicutes/Bacteroidetes ratio was associated with increased IMT (mean Firmicutes/Bacteroidetes ratio of IMT > 0.9 and IMT < 0.9 groups: 2.299 and 1.436, respectively; p = 0.031). In the group with normal IMT values, a substantially higher fraction of Prevotellaceae was observed in contrast with subjects having subclinical atherosclerosis. However, there was no significant difference in the alpha diversity between the two groups. Conclusions: The determining role of individual genera and their proportions in the development and progression of atherosclerosis can be assumed. Further studies are needed to clarify if these findings can be used as potential therapeutic targets.

Trimethylamine N-oxide (TMAO) in human health

Due to numerous links between trimethylamine-N-oxide (TMAO) and various disorders and diseases, this topic is very popular and is often taken up by researchers. TMAO is a low molecular weight compound that belongs to the class of amine oxides. It is formed by the process of oxidation of trimethylamine (TMA) by the hepatic flavin monooxygenases (FMO1 and FMO3). TMAO is mainly formed from nutritional substrates from the metabolism of phosphatidylcholine/choline, carnitine, betaine, dimethylglycine, and ergothioneine by intestinal microflora in the colon. Its level is determined by many factors, such as age, gender, diet, intestinal microflora composition, kidney function, and also liver flavin monooxygenase activity. Many studies report a positive relationship between the level of TMAO concentration and the development of various diseases, such as cardiovascular diseases and cardiorenal disorders, including atherosclerosis, hypertension, ischemic stroke, atrial fibrillation, heart failure, acute myocardial infarction, and chronic kidney disease, and also diabetes mellitus, metabolic syndrome, cancers (stomach, colon), as well as neurological disorders. In this review, we have summarized the current knowledge on the effects of TMAO on human health, the relationship between TMAO and intestinal microbiota, the role of TMAO in different diseases, and current analytical techniques used in TMAO determination in body fluids.

Protective effect of Ganoderma lucidum spore extract in trimethylamine-N-oxide-induced cardiac dysfunction in rats

Previous research has shown that the extracts from the Ganoderma lucidum spore (GS) have potentially cardioprotective effects, but there is still abundant room for development in determining its mechanism. In this study, the rat model of cardiac dysfunction was established by intraperitoneal injection of trimethylamine-N-oxide (TMAO), and the extracts of GS (oil, lipophilic components, and polysaccharides) were given intragastrically at a dose of 50 mg/kg/day to screen the pharmacological active components of GS. After 50 days of treatments, we found that the extraction from GS reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein; increased the levels of high-density lipoprotein; and reduced the levels of serum TMAO when compared to the model group (P < 0.05); especially the GS polysaccharides (DT) and GS lipophilic components (XF) exhibited decreases in serum TMAO compared to TMAO-induced control. The results of 16S rRNA sequencing showed that GS could change the gut microbiota, increasing the abundance of Firmicutes and Proteobacteria in the DT-treated group and XF-treated group, while reducing the abundance of Actinobacteria and Tenericutes. Quantitative proteomics analysis showed that GS extracts (DT and XF) could regulate the expression of some related proteins, such as Ucp1 (XF-TMAO/M-TMAO ratio is 2.76), Mpz (8.52), Fasn (2.39), Nefl (1.85), Mtnd5 (0.83), Mtnd2 (0.36), S100a8 (0.69), S100a9 (0.70), and Bdh1 (0.72). The results showed that XF can maintain the metabolic balance and function of the heart by regulating the expression of some proteins related to cardiovascular disease, and DT can reduce the risk of cardiovascular diseases by targeting gut microbiota.

The Potential Benefit of Monitoring Oxidative Stress and Inflammation in the Prevention of Non-Communicable Diseases (NCDs)

The significant increase in worldwide morbidity and mortality from non-communicable diseases (NCDs) indicates that the efficacy of existing strategies addressing this crisis may need improvement. Early identification of the metabolic irregularities associated with the disease process may be a key to developing early intervention strategies. Unhealthy lifestyle behaviours are well established drivers of the development of several NCDs, but the impact of such behaviours on health can vary considerably between individuals. How can it be determined if an individual's unique set of lifestyle behaviours is producing disease? Accumulating evidence suggests that lifestyle-associated activation of oxidative and inflammatory processes is primary driver of the cell and tissue damage which underpins the development of NCDs. However, the benefit of monitoring subclinical inflammation and oxidative activity has not yet been established. After reviewing relevant studies in this context, we suggest that quantification of oxidative stress and inflammatory biomarkers during the disease-free prodromal stage of NCD development may have clinical relevance as a timely indicator of the presence of subclinical metabolic changes, in the individual, portending the development of disease. Monitoring markers of oxidative and inflammatory activity may therefore enable earlier and more efficient strategies to both prevent NCD development and/or monitor the effectiveness of treatment.

Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia

Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.

Dietary Apigenin Reduces Induction of LOX-1 and NLRP3 Expression, Leukocyte Adhesion, and Acetylated Low-Density Lipoprotein Uptake in Human Endothelial Cells Exposed to Trimethylamine-N-Oxide

By inducing vascular inflammation, trimethylamine-N-oxide (TMAO) is associated with endothelial dysfunction, atherosclerosis, and enhanced risk of cardiovascular diseases in humans. However, the underlying mechanisms are unknown. Expression of several genes related to arteriosclerosis, inflammasomes, and endothelial dysfunction was quantified by polymerase chain reaction after exposure to TMAO. LOX-1, ICAM-1, and NLRP3 were also quantified by Western blot, whereas leukocytic adhesion was examined using fluorescently labeled U937 cells. Scavenger receptors, adhesion molecules, and other genes associated with atherosclerosis were induced in endothelial cells exposed to TMAO. On the other hand, apigenin, a flavonoid that is abundant in parsley and celery, prevents initial arteriosclerosis events in endothelial cells. Apigenin reversed the effects of TMAO on mRNA expression of LOX-1, SREC, SR-PSOX, NLRP3, ASC, TXNIP, VCAM-1, ICAM-1, and MCP-1, as well as protein expression of LOX-1, the adhesion molecule ICAM-1, and the inflammasome protein NLRP3. Apigenin also suppressed leukocyte adhesion and uptake of acetylated low-density lipoprotein. The data indicate that expression of scavenger receptors and adhesion molecules in response to TMAO, along with formation of NLRP3 inflammasomes, may drive endothelial dysfunction through uptake of acetylated low-density lipoprotein and lymphocyte adhesion. Apigenin reverses these effects, implying that it may also prevent arteriosclerosis.

Effects of dietary choline, betaine, and L-carnitine on the generation of trimethylamine-N-oxide in healthy mice

Trimethylamine-N-oxide (TMAO) is considered to have negative effect on human health. Different precursors of TMAO, such as choline, betaine, and L-carnitine, are commonly found in daily foods. The aim of the present study was to compare the ability of different precursors to be metabolized into TMAO, as well as the possible effect of chronic administration with TMAO precursors on TMAO production. The rate of TMAO generation after single gavage with different precursors was L-carnitine > choline >betaine. Moreover, the serum TMAO level of mice increased more than twofold after administration with choline for 3 weeks compared with L-carnitine and betaine groups, which was accompanied by the change of intestinal flora. After the gavage of choline chloride, the production for TMAO was 2.8 and 1.6 times higher in chronic choline-treated group compared with L-carnitine and betaine groups, respectively. In addition, administration with choline increased the lowest TMAO level after intraperitoneal injection of trimethylamine (TMA) hydrochloride among the three treated groups. These findings indicated that different TMAO precursors had different ability to form TMAO in vivo, and long-term dietary intervention would affect the metabolism of precursors to generate TMA and the TMA oxidation to form TMAO, suggesting that TMAO levels in vivo could be regulated by dietary intervention. PRACTICAL APPLICATION: Diverse TMAO precursors exhibited different ability to be converted into TMAO in vivo. The ability of choline to produce TMAO was stronger than that of betaine and L-carnitine. Long-term dietary intervention would affect the metabolism of precursors to generate TMA and the TMA oxidation to form TMAO, suggesting that TMAO levels in vivo could be regulated by adjustment of dietary structure.

Gut Microbiota Metabolism and Interaction with Food Components

The human gut contains trillions of microbes that play a central role in host biology, including the provision of key nutrients from the diet. Food is a major source of precursors for metabolite production; in fact, diet modulates the gut microbiota (GM) as the nutrients, derived from dietary intake, reach the GM, affecting both the ecosystem and microbial metabolic profile. GM metabolic ability has an impact on human nutritional status from childhood. However, there is a wide variability of dietary patterns that exist among individuals. The study of interactions with the host via GM metabolic pathways is an interesting field of research in medicine, as microbiota members produce myriads of molecules with many bioactive properties. Indeed, much evidence has demonstrated the importance of metabolites produced by the bacterial metabolism from foods at the gut level that dynamically participate in various biochemical mechanisms of a cell as a reaction to environmental stimuli. Hence, the GM modulate homeostasis at the gut level, and the alteration in their composition can concur in disease onset or progression, including immunological, inflammatory, and metabolic disorders, as well as cancer. Understanding the gut microbe–nutrient interactions will increase our knowledge of how diet affects host health and disease, thus enabling personalized therapeutics and nutrition.

The Gut Microbial Metabolite Trimethylamine N-Oxide and Hypertension Risk: A Systematic Review and Dose-Response Meta-analysis

The gut microbial metabolite trimethylamine N-oxide (TMAO) is increasingly regarded as a novel risk factor for cardiovascular events and mortality. However, little is known about the association between TMAO and hypertension. This meta-analysis was conducted to quantitatively assess the relation between the circulating TMAO concentration and hypertension prevalence. The PubMed, Cochrane Library, and Embase databases were systematically searched up to 17 June 2018. Studies recording the hypertension prevalence in members of a given population and their circulating TMAO concentrations were included. A total of 8 studies with 11,750 individuals and 6176 hypertensive cases were included in the analytic synthesis. Compared with low circulating TMAO concentrations, high TMAO concentrations were correlated with a higher prevalence of hypertension (RR: 1.12; 95% CI: 1.06, 1.17; P < 0.0001; I2 = 64%; P-heterogeneity = 0.007; random-effects model). Consistent results were obtained in all examined subgroups as well as in the sensitivity analysis. The RR for hypertension prevalence increased by 9% per 5-μmol/L increment (RR: 1.09; 95% CI: 1.05, 1.14; P < 0.0001) and 20% per 10-μmol/L increment of circulating TMAO concentration (RR: 1.20; 95% CI: 1.11, 1.30; P < 0.0001) according to the dose-response meta-analysis. To our knowledge, this is the first systematic review and meta-analysis demonstrating a significant positive dose-dependent association between circulating TMAO concentrations and hypertension risk.

Prognostic Value of Plasma Trimethylamine N-Oxide Levels in Patients with Acute Ischemic Stroke

Trimethylamine N-oxide (TMAO) has emerged as a newly identified gut microbiota-dependent metabolite contributing to a variety of diseases, such as diabetes, atherosclerosis, and cardiovascular diseases. The aim of our study was to determine whether a relatively high TMAO level is associated with an increased risk of poor outcome in ischemic stroke patients. From June 2018 to December 2018, we prospectively recruited acute ischemic stroke patients diagnosed within 24 h of symptom onset. The plasma TMAO level was measured at admission for all patients. Functional outcome was evaluated at 3 months after the stroke using the modified Rankin Scale (mRS) and then dichotomized as favorable (mRS 0-2) or unfavorable (mRS 3-6). A multivariate logistic regression analysis was conducted to evaluate the association between TMAO concentration and poor functional outcome and mortality at 3 months. Of the 225 acute ischemic stroke patients included in the analysis, the median TMAO concentration was 3.8 µM (interquartile range, 1.9-4.8 µM). At 3 months after admission, poor functional outcome was observed in 116 patients (51.6%), and 51 patients had died (22.7%). After adjusting for potential confounders, patients with TMAO levels in the highest quartile were more likely to have higher risks of poor functional outcome [compared with the lowest quartile, odds ratio (OR) 3.63; 95% confidence interval (CI) 1.34-9.82; P = 0.011] and mortality (OR 4.27; 95% CI 1.07-17.07; P = 0.040). Our data suggest that a high plasma TMAO level upon admission may predict unfavorable clinical outcomes in acute ischemic stroke patients.

[An Experience of Meldonium Use in Patients with Ventricular Arrhythmias of Ischemic Genesis]

Ischemic heart disease (IHD) is often accompanied by cardiac rhythm disturbances particularly ventricular arrhythmias (VA) and their appearance in both chronic and acute forms of IHD is usually regarded as dangerous signal requiring the use of antiarrhythmic drugs. An important addition to hemodynamic therapy can be considered the use of cytoprotective drugs that improve the energy potential of cardiomyocytes. The purpose of this work is to study the comparative evaluation of the Mildronate effectiveness in patients with IHD and VA.

METHODS

Under dynamic observation were 147 patients with IHD and VA (Lown II-IV functional class). The diagnosis of angina pectoris was confirmed by clinical, exercise bicycle ergometry, Holter ECG monitoring, and echocardiography data. Holter ECG monitoring was used for recording VA, heart rate, episodes of ST-segment depression. The levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol were determined. All patients were randomly divided into 2 groups. The first group (81 patients) received standard antianginal and antiarrhythmic therapy plus meldonium for 2 months. The second (control) group (66 patients) received standard antianginal and antiarrhythmic therapy only. Statistical analysis of the data was carried out using the statistical package SPSS 13.0.

RESULTS

A comparative analysis of the results showed that the use of meldonium in combination with basic therapy significantly improved clinical condition and quality of life indicators, increased exercise tolerance and improved systolic and diastolic dysfunction in patients with IHD and VA. The positive effect of meldonium on LDLC levels was observed. Moreover, the combination of basic antianginal and antiarrhythmic therapy and meldonium in patients with ischemic genesis VA promoted significant reduction of ischemic episodes and decrease of VA, in particular allorhythmia.

CONCLUSION

Results of this study suggest that the use of meldonium in patients with IHD and VA helps to optimize myocardial energy metabolism in conditions of ischemia and reperfusion.

Resveratrol inhibits lipid accumulation in the intestine of atherosclerotic mice and macrophages

Disordered intestinal metabolism is highly correlated with atherosclerotic diseases. Resveratrol protects against atherosclerotic diseases. Accordingly, this study aims to discover novel intestinal proatherosclerotic metabolites and potential therapeutic targets related to the anti‐atherosclerotic effects of resveratrol. An untargeted metabolomics approach was employed to discover novel intestinal metabolic disturbances during atherosclerosis and resveratrol intervention. We found that multiple intestinal metabolic pathways were significantly disturbed during atherosclerosis and responsive to resveratrol intervention. Notably, resveratrol abolished intestinal fatty acid and monoglyceride accumulation in atherosclerotic mice. Meanwhile, oleate accumulation was one of the most prominent alterations in intestinal metabolism. Moreover, resveratrol attenuated oleate‐triggered accumulation of total cholesterol, esterified cholesterol and neutral lipids in mouse RAW 264.7 macrophages by activating ABC transporter A1/G1‐mediated cholesterol efflux through PPAR (peroxisome proliferator‐activated receptor) α/γ activation. Furthermore, we confirmed that PPARα and PPARγ activation by WY14643 and pioglitazone, respectively, alleviated oleate‐induced accumulation of total cholesterol, esterified cholesterol and neutral lipids by accelerating ABC transporter A1/G1‐mediated cholesterol efflux. This study provides the first evidence that resveratrol abolishes intestinal fatty acid and monoglyceride accumulation in atherosclerotic mice, and that resveratrol suppresses oleate‐induced accumulation of total cholesterol, esterified cholesterol and neutral lipids in macrophages by activating PPARα/γ signalling.

Cholesterol cholelithiasis: part of a systemic metabolic disease, prone to primary prevention

Cholesterol gallstone disease have relationships with various conditions linked with insulin resistance, but also with heart disease, atherosclerosis, and cancer. These associations derive from mechanisms active at a local (i.e. gallbladder, bile) and a systemic level and are involved in inflammation, hormones, nuclear receptors, signaling molecules, epigenetic modulation of gene expression, and gut microbiota. Despite advanced knowledge of these pathways, the available therapeutic options for symptomatic gallstone patients remain limited. Therapy includes oral litholysis by the bile acid ursodeoxycholic acid (UDCA) in a small subgroup of patients at high risk of postdissolution recurrence, or laparoscopic cholecystectomy, which is the therapeutic radical gold standard treatment. Cholecystectomy, however, may not be a neutral event, and potentially generates health problems, including the metabolic syndrome. Areas covered: Several studies on risk factors and pathogenesis of cholesterol gallstone disease, acting at a systemic level have been reviewed through a PubMed search. Authors have focused on primary prevention and novel potential therapeutic strategies. Expert commentary: The ultimate goal appears to target the manageable systemic mechanisms responsible for gallstone occurrence, pointing to primary prevention measures. Changes must target lifestyles, as well as experimenting innovative pharmacological tools in subgroups of patients at high risk of developing gallstones.

Nonalcoholic fatty liver disease and chronic vascular complications of diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus are common diseases that often coexist and might act synergistically to increase the risk of hepatic and extra-hepatic clinical outcomes. NAFLD affects up to 70-80% of patients with type 2 diabetes mellitus and up to 30-40% of adults with type 1 diabetes mellitus. The coexistence of NAFLD and diabetes mellitus increases the risk of developing not only the more severe forms of NAFLD but also chronic vascular complications of diabetes mellitus. Indeed, substantial evidence links NAFLD with an increased risk of developing cardiovascular disease and other cardiac and arrhythmic complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus. NAFLD is also associated with an increased risk of developing microvascular diabetic complications, especially chronic kidney disease. This Review focuses on the strong association between NAFLD and the risk of chronic vascular complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus, thereby promoting an increased awareness of the extra-hepatic implications of this increasingly prevalent and burdensome liver disease. We also discuss the putative underlying mechanisms by which NAFLD contributes to vascular diseases, as well as the emerging role of changes in the gut microbiota (dysbiosis) in the pathogenesis of NAFLD and associated vascular diseases.

Balancing Herbal Medicine and Functional Food for Prevention and Treatment of Cardiometabolic Diseases through Modulating Gut Microbiota

It has become apparent that gut microbiota is closely associated with cardiometabolic diseases (CMDs), and alteration in microbiome compositions is also linked to the host environment. Next generation sequencing (NGS) has facilitated in-depth studies on the effects of herbal medicine and functional food on gut microbiota. Both herbal medicine and functional food contain fiber, polyphenols and polysaccharides, exerting prebiotics-like activities in the prevention and treatment of CMDs. The administrations of herbal medicine and functional food lead to increased the abundance of phylum Bacteroidetes, and genus Akkermansia, Bifidobacteria, Lactobacillus, Bacteroides and Prevotella, while reducing phylum Firmicutes and Firmicutes/Bacteroidetes ratio in gut. Both herbal medicine and functional food interact with gut microbiome and alter the microbial metabolites including short-chain fatty acids (SCFAs), bile acids (BAs) and lipopolysaccharides (LPS), which are now correlated with metabolic diseases such as type 2 diabetes (T2D), obesity and non-alcoholic fatty liver disease (NAFLD). In addition, trimethylamine (TMA)-N-oxide (TMAO) is recently linked to atherosclerosis (AS) and cardiovascular disease (CVD) risks. Moreover, gut-organs axes may serve as the potential strategy for treating CMDs with the intervention of herbal medicine and functional food. In summary, a balance between herbal medicine and functional food rich in fiber, polyphenols and polysaccharides plays a vital role in modulating gut microbiota (phylum Bacteroidetes, Firmicutes and Firmicutes/Bacteroidetes ratio, and genus Akkermansia, Bifidobacteria, Lactobacillus, Bacteroides and Prevotella) through SCFAs, BAs, LPS and TMAO signaling regarding CMDs. Targeting gut-organs axes may serve as a new therapeutic strategy for CMDs by herbal medicine and functional food in the future. This review aims to summarize the balance between herbal medicine and functional food utilized for the prevention and treatment of CMDs through modulating gut microbiota.

Inactivation mechanism of N61S mutant of human FMO3 towards trimethylamine

Human flavin-containing monooxygenase 3 (hFMO3) catalyses the oxygenation of a wide variety of compounds including drugs as well as dietary compounds. It is the major hepatic enzyme involved in the production of the N-oxide of trimethylamine (TMAO) and clinical studies have uncovered a striking correlation between plasma TMAO concentration and cardiovascular disease. Certain mutations within the hFMO3 gene cause defective trimethylamine (TMA) N-oxygenation leading to trimethylaminuria (TMAU) also known as fish-odour syndrome. In this paper, the inactivation mechanism of a TMAU-causing polymorphic variant, N61S, is investigated. Transient kinetic experiments show that this variant has a > 170-fold lower NADPH binding affinity than the wild type. Thermodynamic and spectroscopic experiments reveal that the poor NADP⁺ binding affinity accelerates the C4a-hydroperoxyFAD intermediate decay, responsible for an unfavourable oxygen transfer to the substrate. Steady-state kinetic experiments show significantly decreased N61S catalytic activity towards other substrates; methimazole, benzydamine and tamoxifen. The in vitro data are corroborated by in silico data where compared to the wild type enzyme, a hydrogen bond required for the stabilisation of the flavin intermediate is lacking. Taken together, the data presented reveal the molecular basis for the loss of function observed in N61S mutant.

Cardiovascular and Antiobesity Effects of Resveratrol Mediated through the Gut Microbiota

Encouraging scientific research into the health effects of dietary bioactive resveratrol has been confounded by its rapid first-pass metabolism, which leads to low in vivo bioavailability. Preliminary studies have shown that resveratrol can modulate gut microbiota composition, undergo biotransformation to active metabolites via the intestinal microbiota, or affect gut barrier function. In rodents, resveratrol can modify the relative Bacteroidetes:Firmicutes ratio and reverse the gut microbial dysbiosis caused by a high-fat diet. By upregulating the expression of genes involved in maintaining tight junctions between intestinal cells, resveratrol contributes to gut barrier integrity. The composition of the gut microbiome and rapid metabolism of resveratrol determines the production of resveratrol metabolites, which are found at greater concentrations in humans after ingestion than their parent molecule and can have similar biological effects. Resveratrol may affect cardiovascular risk factors such as elevated blood cholesterol or trimethylamine N-oxide concentrations. Modulating the composition of the gut microbiota by resveratrol may affect central energy metabolism and modify concentrations of satiety hormones to produce antiobesity effects. Encouraging research from animal models could be tested in humans.

Perinatal Hypercholesterolemia Exacerbates Atherosclerosis Lesions in Offspring by Altering Metabolism of Trimethylamine-N-Oxide and Bile Acids

OBJECTIVE

Experimental studies suggest that maternal hypercholesterolemia may be relevant for the early onset of cardiovascular disease in offspring. We investigated the effect of perinatal hypercholesterolemia on the atherosclerosis development in the offspring of apolipoprotein E-deficient mice and the underlying mechanism.

APPROACH AND RESULTS

Atherosclerosis and related parameters were studied in adult male or female apolipoprotein E-deficient mice offspring from either normocholesterolemic or hypercholesterolemic mothers and normocholesterolemic fathers. Female born to hypercholesterolemic mothers had more aortic root lesions than female born to normocholesterolemic mothers. Lesions in whole aorta did not differ between groups. Higher trimethylamine-N-oxide levels and Fmo3 hepatic gene expression were higher in female born to hypercholesterolemic mothers offspring compared with female born to normocholesterolemic mothers and male. Trimethylamine-N-oxide levels were correlated with the size of atherosclerotic root lesions. Levels of hepatic cholesterol and gallbladder bile acid were greater in male born to hypercholesterolemic mothers compared with male born to normocholesterolemic mothers. At 18 weeks of age, female born to hypercholesterolemic mothers showed lower hepatic Scarb1 and Cyp7a1 but higher Nr1h4 gene expression compared with female born to normocholesterolemic mothers. Male born to hypercholesterolemic mothers showed an increase in Scarb1 and Ldlr gene expression compared with male born to normocholesterolemic mothers. At 25 weeks of age, female born to hypercholesterolemic mothers had lower Cyp7a1 gene expression compared with female born to normocholesterolemic mothers. DNA methylation of Fmo3, Scarb1, and Ldlr promoter regions was slightly modified and may explain the mRNA expression modulation.

CONCLUSIONS

Our findings suggest that maternal hypercholesterolemia may exacerbate the development of atherosclerosis in female offspring by affecting metabolism of trimethylamine-N-oxide and bile acids. These data could be explained by epigenetic alterations.

Cell-Surface and Nuclear Receptors in the Colon as Targets for Bacterial Metabolites and Its Relevance to Colon Health

The symbiotic co-habitation of bacteria in the host colon is mutually beneficial to both partners. While the host provides the place and food for the bacteria to colonize and live, the bacteria in turn help the host in energy and nutritional homeostasis, development and maturation of the mucosal immune system, and protection against inflammation and carcinogenesis. In this review, we highlight the molecular mediators of the effective communication between the bacteria and the host, focusing on selective metabolites from the bacteria that serve as messengers to the host by acting through selective receptors in the host colon. These bacterial metabolites include the short-chain fatty acids acetate, propionate, and butyrate, the tryptophan degradation products indole-3-aldehyde, indole-3-acetic, acid and indole-3-propionic acid, and derivatives of endogenous bile acids. The targets for these bacterial products in the host include the cell-surface G-protein-coupled receptors GPR41, GPR43, and GPR109A and the nuclear receptors aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), and farnesoid X receptor (FXR). The chemical communication between these bacterial metabolite messengers and the host targets collectively has the ability to impact metabolism, gene expression, and epigenetics in colonic epithelial cells as well as in mucosal immune cells. The end result, for the most part, is the maintenance of optimal colonic health.

Gut Microbiota Metabolites and Risk of Major Adverse Cardiovascular Disease Events and Death: A Systematic Review and Meta-Analysis of Prospective Studies

BACKGROUND

Gut microbial metabolites have been implicated as novel risk factors for cardiovascular events and premature death. The strength and consistency of associations between blood concentrations of the gut microbial metabolites, trimethylamine-N-oxide (TMAO) and its precursors, with major adverse cardiovascular events (MACE) or death have not been comprehensively assessed. We quantified associations of blood concentrations of TMAO and its precursors with risks of MACE and mortality.

METHODS AND RESULTS

PubMed and Embase databases were searched up, and a total of 19 prospective studies from 16 publications (n=19 256, including 3315 incident cases) with quantitative estimates of the associations of TMAO with the development of MACE or death were included in our main analysis. Multivariate-adjusted relative risks (RRs) were used when these were available. Elevated concentrations of TMAO were associated with a pooled RR of 1.62 (95% CI, 1.45, 1.80; P_{heterogeneity}=0.2; I²=23.5%) for MACE compared with low TMAO levels, and 1 study of black participants influenced the heterogeneity of the association. After excluding the data of blacks, the RRs were not different according to body mass index, prevalence of diabetes mellitus, history of cardiovascular diseases, and kidney dysfunction. Furthermore, elevated TMAO concentrations were associated with a pooled RR of 1.63 (1.36, 1.95) for all-cause mortality. Individuals with elevated concentrations of TMAO precursors (l-carnitine, choline, or betaine) had an approximately 1.3 to 1.4 times higher risk for MACE compared to those with low concentrations.

CONCLUSIONS

Elevated concentrations of TMAO and its precursors were associated with increased risks of MACE and all-cause mortality independently of traditional risk factors.