Bifidobacterium animalis subsp. lactis LKM512 reduces levels of intestinal trimethylamine produced by intestinal microbiota in healthy volunteers: A double-blind, placebo-controlled study

Reinforcing gut integrity: A systematic review and meta-analysis of clinical trials assessing probiotics, synbiotics, and prebiotics on intestinal permeability markers

BACKGROUND

Given the magnitude and variety of chronic metabolic disease linked to increased intestinal permeability, appropriate strategies to reinforce gut barrier function are urgently needed.

METHODS

This systematic review and meta-analysis explores the effects of pro- and synbiotic, or prebiotic administration, on various intestinal permeability markers. Systematic searches across the Medline and Scopus databases were performed from 1961 to January 2023. The review included data from 46 published studies on pro- and synbiotics, and 22 studies on prebiotics. 46 The meta-analysis calculated standardized mean differences (SMD) along with 95 % confidence intervals (95 %CIs) using a random-effects model to evaluate the average effect sizes (ES). To analyze heterogeneity, we employed Galbraith plots and performed the Cochrane Chi-squared test.

RESULTS

The analysis on 24 trials (28 ES, n = 1603) revealed a significant reduction in lipopolysaccharide levels following pro- and synbiotics consumption with high heterogeneity and very low certainty of evidence (SMD (95 %CI) = -0.54 (-1.01, -0.07); I2 (%) = 94.4). Synthesis of 13 trials showed zonulin levels were significantly lowered after pro- and synbiotics consumption with high heterogeneity and moderate certainty of evidence (15 ES, n=778) (SMD (95 %CI) = -0.49 (-0.79, -0.18); I2 (%) = 74.9). Following prebiotics supplementation, a significant reduction in lipopolysaccharide levels was observed, with high heterogeneity identified from data including 16 RCTs (n = 792; SMD (95 %CI) = -0.88 (-1.28, -0.47); P < 0.001; high certainty of evidence; I2 (%) = 85.7; P-heterogeneity< 0.001).

CONCLUSION

This meta-analysis revealed promising findings regarding the efficacy of pro- and synbiotic and prebiotic supplements in alleviating "leaky gut".

The Role of Gut Microbiota-Derived Trimethylamine N-Oxide in the Pathogenesis and Treatment of Mild Cognitive Impairment

Mild cognitive impairment (MCI) represents a transitional stage between normal aging and dementia, often considered critical for dementia prevention. Despite its significance, no effective clinical treatment for MCI has yet been established. Emerging evidence has demonstrated a strong association between trimethylamine-N-oxide (TMAO), a prominent metabolite derived from the gut microbiota, and MCI, highlighting its potential as a biomarker and therapeutic target. TMAO has been implicated in increasing MCI risk through its influence on factors such as hypertension, cardiovascular disease, depression, diabetes, and stroke. Moreover, it contributes to MCI by promoting oxidative stress, disrupting the blood-brain barrier, impairing synaptic plasticity, inducing inflammation, causing mitochondrial metabolic disturbances, and facilitating abnormal protein aggregation. This review further explores therapeutic strategies targeting TMAO to mitigate MCI progression.

Therapeutic potential of lipid-lowering probiotics on the atherosclerosis development

Hypercholesterolemia is a critical risk factor for atherosclerosis, mostly attributed to lifestyle behavior such as diet. Recent advances have emphasized the critical effects of gastrointestinal bacteria in the pathology of hypercholesterolemia and atherosclerosis, suggesting that the gastrointestinal microbiome can therefore provide efficient therapeutic targets for preventing and treating atherosclerosis. Thus, interventions, such as probiotic therapy, aimed at altering the bacterial composition introduce a promising therapeutic procedure. In the current review, we will provide an overview of anti-atherogenic probiotics contributing to lipid-lowering, inhibiting atherosclerotic inflammation, and suppressing bacterial atherogenic metabolites.

Randomized clinical trial evaluating the efficacy of synbiotic supplementation on serum endotoxin and trimethylamine N-oxide levels in patients with dyslipidaemia

Introduction

Elevated serum endotoxin and trimethylamine N-oxide (TMAO) are associated with metabolic disorders including dyslipidaemia and insulin resistance. This study aimed to evaluate the impact of a 12-week treatment with a synbiotic supplement on serum endotoxin and TMAO levels in patients diagnosed with dyslipidaemia.

Material and methods

A total of 56 patients who met the study inclusion criteria were recruited in this randomized, double-blind clinical trial. Participants were randomly assigned into intervention and control groups and received either synbiotic or placebo sachets twice a day for 12 weeks. The sociodemographic data, food intake, physical activity, and anthropometric indices of participants were assessed before and after intervention. Serum endotoxin, TMAO, and fasting blood glucose (FBG) levels were measured at the baseline and end of the study.

Results

No significant difference in the baseline characteristics of participants in the 2 groups was observed. After the 12 weeks of intervention, the mean of serum endotoxin (p < 0.0001), TMAO (p < 0.0001), and FBG (p < 0.0001) was decreased in patients who received synbiotic supplements while no significant change was observed in the control group. Moreover, a significant positive correlation between changes in endotoxin (r = 0.41, p = 0.041) and TMAO (r = 0.40, p = 0.047) with FBG changes was observed.

Conclusions

A significant reduction in serum endotoxin and TMAO levels, as well as improvements in FBG, following 12 weeks of supplementation with synbiotics, may offer a potential approach for improving metabolic status in patients with dyslipidaemia.

Probiotic treatment with Bifidobacterium animalis subsp. lactis LKM512 + arginine improves cognitive flexibility in middle-aged mice

Cognitive flexibility, the ability of adapting to an ever-changing environment, declines with aging and impaired in early stages of dementia. Although recent studies have indicated there is a relationship between the intestinal microbiota and cognitive function, few studies have shown relationships between intestinal microbiota and cognitive flexibility because of limited behavioural tasks in mice. We recently established a novel cognitive flexibility task for mice using a touchscreen operant apparatus and found that probiotic treatment with a mixture of Bifidobacterium animalis subsp. lactis LKM512 and arginine improved cognitive flexibility in young adult mice. To confirm the effects of the probiotic treatment on cognitive flexibility and to determine whether it is effective even in older age, we here examined the effects of long-term treatment with Bifidobacterium animalis subsp. lactis LKM512 and arginine on cognitive flexibility in middle-aged mice. From 8 to 15 months of age, mice received LKM + Arg or vehicle (controls) orally three times per week and were subjected to the cognitive flexibility task at 13-15 months old. In one of indices of cognitive flexibility, both Bifidobacterium animalis subsp. lactis LKM512 and arginine-treated mice and vehicle-treated mice showed progressively improved performance by repeating reversal tasks, with a small trend that Bifidobacterium animalis subsp. lactis LKM512 and arginine-treated mice showed better learning performance through reversal phases. With respect to the other index of cognitive flexibility, Bifidobacterium animalis subsp. lactis LKM512 and arginine-treated mice showed significantly fewer error choices than control mice at the reversal phase, i.e. Bifidobacterium animalis subsp. lactis LKM512 and arginine improved the performance of behavioural sequencing acquired in the previous phase, which allowed Bifidobacterium animalis subsp. lactis LKM512 and arginine-treated mice to show an early onset of shift to reversal contingency. Taken together, long-term treatment with Bifidobacterium animalis subsp. lactis LKM512 and arginine was found to improve cognitive flexibility in middle-aged mice, indicating that probiotic treatment might contribute to prevention of age-related cognitive decline.

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.

The therapeutic value of bifidobacteria in cardiovascular disease

There has been an increase in cardiovascular morbidity and mortality over the past few decades, making cardiovascular disease (CVD) the leading cause of death worldwide. However, the pathogenesis of CVD is multi-factorial, complex, and not fully understood. The gut microbiome has long been recognized to play a critical role in maintaining the physiological and metabolic health of the host. Recent scientific advances have provided evidence that alterations in the gut microbiome and its metabolites have a profound influence on the development and progression of CVD. Among the trillions of microorganisms in the gut, bifidobacteria, which, interestingly, were found through the literature to play a key role not only in regulating gut microbiota function and metabolism, but also in reducing classical risk factors for CVD (e.g., obesity, hyperlipidemia, diabetes) by suppressing oxidative stress, improving immunomodulation, and correcting lipid, glucose, and cholesterol metabolism. This review explores the direct and indirect effects of bifidobacteria on the development of CVD and highlights its potential therapeutic value in hypertension, atherosclerosis, myocardial infarction, and heart failure. By describing the key role of Bifidobacterium in the link between gut microbiology and CVD, we aim to provide a theoretical basis for improving the subsequent clinical applications of Bifidobacterium and for the development of Bifidobacterium nutritional products.

Gut microbiota and anti-aging: Focusing on spermidine

The human gut microbiota plays numerous roles in regulating host growth, the immune system, and metabolism. Age-related changes in the gut environment lead to chronic inflammation, metabolic dysfunction, and illness, which in turn affect aging and increase the risk of neurodegenerative disorders. Local immunity is also affected by changes in the gut environment. Polyamines are crucial for cell development, proliferation, and tissue regeneration. They regulate enzyme activity, bind to and stabilize DNA and RNA, have antioxidative properties, and are necessary for the control of translation. All living organisms contain the natural polyamine spermidine, which has anti-inflammatory and antioxidant properties. It can regulate protein expression, prolong life, and improve mitochondrial metabolic activity and respiration. Spermidine levels experience an age-related decrease, and the development of age-related diseases is correlated with decreased endogenous spermidine concentrations. As more than just a consequence, this review explores the connection between polyamine metabolism and aging and identifies advantageous bacteria for anti-aging and metabolites they produce. Further research is being conducted on probiotics and prebiotics that support the uptake and ingestion of spermidine from food extracts or stimulate the production of polyamines by gut microbiota. This provides a successful strategy to increase spermidine levels.

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.

The role of polyamine metabolism in remodeling immune responses and blocking therapy within the tumor immune microenvironment

The study of metabolism provides important information for understanding the biological basis of cancer cells and the defects of cancer treatment. Disorders of polyamine metabolism is a common metabolic change in cancer. With the deepening of understanding of polyamine metabolism, including molecular functions and changes in cancer, polyamine metabolism as a new anti-cancer strategy has become the focus of attention. There are many kinds of polyamine biosynthesis inhibitors and transport inhibitors, but not many drugs have been put into clinical application. Recent evidence shows that polyamine metabolism plays essential roles in remodeling the tumor immune microenvironment (TIME), particularly treatment of DFMO, an inhibitor of ODC, alters the immune cell population in the tumor microenvironment. Tumor immunosuppression is a major problem in cancer treatment. More and more studies have shown that the immunosuppressive effect of polyamines can help cancer cells to evade immune surveillance and promote tumor development and progression. Therefore, targeting polyamine metabolic pathways is expected to become a new avenue for immunotherapy for cancer.

Tackling Atherosclerosis via Selected Nutrition

The development and pathogenesis of atherosclerosis are significantly influenced by lifestyle, particularly nutrition. The modern level of science and technology development promote personalized nutrition as an efficient preventive measure against atherosclerosis. In this survey, the factors were revealed that contribute to the formation of an individual approach to nutrition: genetic characteristics, the state of the microbiota of the gastrointestinal tract (GIT) and environmental factors (diets, bioactive components, cardioprotectors, etc.). In the course of the work, it was found that in order to analyze the predisposition to atherosclerosis associated with nutrition, genetic features affecting the metabolism of nutrients are significant. The genetic features include the presence of single nucleotide polymorphisms (SNP) of genes and epigenetic factors. The influence of telomere length on the pathogenesis of atherosclerosis and circadian rhythms was also considered. Relatively new is the study of the relationship between chrono-nutrition and the development of metabolic diseases. That is, to obtain the relationship between nutrition and atherosclerosis, a large number of genetic markers should be considered. In this relation, the question arises: "How many genetic features need to be analyzed in order to form a personalized diet for the consumer?" Basically, companies engaged in nutrigenetic research and choosing a diet for the prevention of a number of metabolic diseases use SNP analysis of genes that accounts for lipid metabolism, vitamins, the body's antioxidant defense system, taste characteristics, etc. There is no set number of genetic markers. The main diets effective against the development of atherosclerosis were considered, and the most popular were the ketogenic, Mediterranean, and DASH-diets. The advantage of these diets is the content of foods with a low amount of carbohydrates, a high amount of vegetables, fruits and berries, as well as foods rich in antioxidants. However, due to the restrictions associated with climatic, geographical, material features, these diets are not available for a number of consumers. The way out is the use of functional products, dietary supplements. In this approach, the promising biologically active substances (BAS) that exhibit anti-atherosclerotic potential are: baicalin, resveratrol, curcumin, quercetin and other plant metabolites. Among the substances, those of animal origin are popular: squalene, coenzyme Q10, omega-3. For the prevention of atherosclerosis through personalized nutrition, it is necessary to analyze the genetic characteristics (SNP) associated with the metabolism of nutrients, to assess the state of the microbiota of the GIT. Based on the data obtained and food preferences, as well as the individual capabilities of the consumer, the optimal diet can be selected. It is topical to exclude nutrients of which their excess consumption stimulates the occurrence and pathogenesis of atherosclerosis and to enrich the diet with functional foods (FF), BAS containing the necessary anti-atherosclerotic, and stimulating microbiota of the GIT nutrients. Personalized nutrition is a topical preventive measure and there are a number of problems hindering the active use of this approach among consumers. The key factors include weak evidence of the influence of a number of genetic features, the high cost of the approach, and difficulties in the interpretation of the results. Eliminating these deficiencies will contribute to the maintenance of a healthy state of the population through nutrition.

Associations between the gut microbiome, gut microbiology and heart failure: Current understanding and future directions

The role of the gut microbiome in pathophysiology, prognostication and clinical management of heart failure (HF) patients is of great clinical and research interest. Both preclinical and clinical studies have shown promising results, and the gut microbiome has been implicated in other cardiovascular conditions that are risk factors for HF. There is an increasing interest in the use of biological compounds produced as biomarkers for prognostication as well as exploration of therapeutic options targeting the various markers and pathways from the gut microbiome that are implicated in HF. However, study variations exist, and targeted research for individual putative biomarkers is necessary. There is also limited evidence pertaining to decompensated HF in particular. In this review, we synthesize current understandings around pathophysiology, prognostication and clinical management of heart failure (HF) patients, and also provide an outline of potential areas of future research and scientific advances.

Bifidobacterium lactis Probio-M8 Adjuvant Treatment Confers Added Benefits to Patients with Coronary Artery Disease via Target Modulation of the Gut-Heart/-Brain Axes

Accumulating evidence suggests that gut dysbiosis may play a role in cardiovascular problems like coronary artery disease (CAD). Thus, target steering the gut microbiota/metabolome via probiotic administration could be a promising way to protect against CAD. A 6-month randomized, double-blind, placebo-controlled clinical trial was conducted to investigate the added benefits and mechanism of the probiotic strain, Bifidobacterium lactis Probio-M8, in alleviating CAD when given together with a conventional regimen. Sixty patients with CAD were randomly divided into a probiotic group (n = 36; received Probio-M8, atorvastatin, and metoprolol) and placebo group (n = 24; placebo, atorvastatin, and metoprolol). Conventional treatment significantly improved the Seattle Angina Questionnaire (SAQ) scores of the placebo group after the intervention. However, the probiotic group achieved even better SAQ scores at day 180 compared with the placebo group (P < 0.0001). Moreover, Probio-M8 treatment was more conducive to alleviating depression and anxiety in patients (P < 0.0001 versus the placebo group, day 180), with significantly lower serum levels of interleukin-6 and low-density lipoprotein cholesterol (P < 0.005 and P < 0.001, respectively). In-depth metagenomic analysis showed that, at day 180, significantly more species-level genome bins (SGBs) of Bifidobacterium adolescentis, Bifidobacterium animalis, Bifidobacterium bifidum, and Butyricicoccus porcorum were detected in the probiotic group compared with the placebo group, while the abundances of SGBs representing Flavonifractor plautii and Parabacteroides johnsonii decreased significantly among the Probio-M8 receivers (P < 0.05). Furthermore, significantly more microbial bioactive metabolites (e.g., methylxanthine and malonate) but less trimethylamine-N-oxide and proatherogenic amino acids were detected in the probiotic group than placebo group during/after intervention (P < 0.05). Collectively, we showed that coadministering Probio-M8 synergized with a conventional regimen to improve the clinical efficacy in CAD management. The mechanism of the added benefits was likely achieved via probiotic-driven modulation of the host's gut microbiota and metabolome, consequently improving the microbial metabolic potential and serum metabolite profile. This study highlighted the significance of regulating the gut-heart/-brain axes in CAD treatment. IMPORTANCE Despite recent advances in therapeutic strategies and drug treatments (e.g., statins) for coronary artery disease (CAD), CAD-related mortality and morbidity remain high. Active bidirectional interactions between the gut microbiota and the heart implicate that probiotic application could be a novel therapeutic strategy for CAD. This study hypothesized that coadministration of atorvastatin and probiotics could synergistically protect against CAD. Our results demonstrated that coadministering Probio-M8 with a conventional regimen offered added benefits to patients with CAD compared with conventional treatment alone. Our findings have provided a wide and integrative view of the pathogenesis and novel management options for CAD and CAD-related diseases.

Emerging connections between gut microbiome bioenergetics and chronic metabolic diseases

The conventional viewpoint of single-celled microbial metabolism fails to adequately depict energy flow at the systems level in host-adapted microbial communities. Emerging paradigms instead support that distinct microbiomes develop interconnected and interdependent electron transport chains that rely on cooperative production and sharing of bioenergetic machinery (i.e., directly involved in generating ATP) in the extracellular space. These communal resources represent an important subset of the microbial metabolome, designated here as the "pantryome" (i.e., pantry or external storage compartment), that critically supports microbiome function and can exert multifunctional effects on host physiology. We review these interactions as they relate to human health by detailing the genomic-based sharing potential of gut-derived bacterial and archaeal reference strains. Aromatic amino acids, metabolic cofactors (B vitamins), menaquinones (vitamin K2), hemes, and short-chain fatty acids (with specific emphasis on acetate as a central regulator of symbiosis) are discussed in depth regarding their role in microbiome-related metabolic diseases.

Fecal microbiota composition associates with the capacity of human peripheral blood monocytes to differentiate into immunogenic dendritic cells in vitro

Although promising for active immunization in cancer patients, dendritic cells (DCs) vaccines generated in vitro display high inter-individual variability in their immunogenicity, which mostly limits their therapeutic efficacy. Gut microbiota composition is a key emerging factor affecting individuals' immune responses, but it is unknown how it affects the variability of donors' precursor cells to differentiate into immunogenic DCs in vitro. By analyzing gut microbiota composition in 14 healthy donors, along with the phenotype and cytokines production by monocyte-derived DCs, we found significant correlations between immunogenic properties of DC and microbiota composition. Namely, donors who had higher α-diversity of gut microbiota and higher abundance of short-chain fatty acid (SCFAs) and SCFA-producing bacteria in feces, displayed lower expression of CD1a on immature (im)DC and higher expression of ILT-3, costimulatory molecules (CD86, CD40) proinflammatory cytokines (TNF-α, IL-6, IL-8) and IL-12p70/IL-10 ratio, all of which correlated with their lower maturation potential and immunogenicity upon stimulation with LPS/IFNγ, a well-known Th1 polarizing cocktail. In contrast, imDCs generated from donors with lower α-diversity and higher abundance of Bifidobacterium and Collinsella in feces displayed higher CD1a expression and higher potential to up-regulate CD86 and CD40, increase TNF-α, IL-6, IL-8 production, and IL-12p70/IL-10 ratio upon stimulation. These results emphasize the important role of gut microbiota on the capacity of donor precursor cells to differentiate into immunogenic DCs suitable for cancer therapy, which could be harnessed for improving the actual and future DC-based cancer therapies.

Polycystic ovary syndrome and cardiovascular risk. Could trimethylamine N-oxide (TMAO) be a major player? A potential upgrade forward in the DOGMA theory

Several studies reported an increase in cardiovascular risk (CVR) in women with polycystic ovary syndrome (PCOS), considered primarily as the result of the combination of all the clinical features that characterize the syndrome, including hyperandrogenism, insulin resistance, diabetes, obesity chronic low-grade inflammation. Interestingly, in 2012 it has been proposed the so-called DOGMA theory, suggesting the pivotal role played by microbiota alteration in the development of PCOS. Subsequently, several authors evidenced the existence in PCOS women of a marked dysbiosis, which is related to the development of metabolic diseases and cardiovascular complications, mainly due to the production of bacteria-derived metabolites that interfere with various pathways. Among these, trimethylamine-N-oxide (TMAO) is emerging as one of the most important and studied microbiota-derived metabolites related to the increase in CVR, due to its pro-atherosclerotic effect. The purpose of the present review is to summarize the evidence in order to support the hypothesis that, in women with PCOS, dysbiosis might be further involved in enhancement of the CVR via contributing to the increase of circulating TMAO. Although no observational studies on a large number of patients directly investigated the serum levels of TMAO in PCOS women, this manuscript aimed to drive future studies in this field, concurring in providing a novel approach for both comprehension and treatment of the CVR in PCOS.

Exploring the Gut Microbiota and Cardiovascular Disease

Cardiovascular disease (CVD) has been classified as one of the leading causes of morbidity and mortality worldwide. CVD risk factors include smoking, hypertension, dyslipidaemia, obesity, inflammation and diabetes. The gut microbiota can influence human health through multiple interactions and community changes are associated with the development and progression of numerous disease states, including CVD. The gut microbiota are involved in the production of several metabolites, such as short-chain fatty acids (SCFAs), bile acids and trimethylamine-N-oxide (TMAO). These products of microbial metabolism are important modulatory factors and have been associated with an increased risk of CVD. Due to its association with CVD development, the gut microbiota has emerged as a target for therapeutic approaches. In this review, we summarise the current knowledge on the role of the gut microbiome in CVD development, and associated microbial communities, functions, and metabolic profiles. We also discuss CVD therapeutic interventions that target the gut microbiota such as probiotics and faecal microbiota transplantation.

TMAO: how gut microbiota contributes to heart failure

An increasing amount of evidence reveals that the gut microbiota is involved in the pathogenesis and progression of various cardiovascular diseases. In patients with heart failure (HF), splanchnic hypoperfusion causes ischemia and intestinal edema, allowing bacterial translocation and bacterial metabolites to enter the blood circulation via an impaired intestinal barrier. This results in local and systemic inflammatory responses. Gut microbe-derived metabolites are implicated in the pathology of multiple diseases, including HF. These landmark findings suggest that gut microbiota influences the host's metabolic health, either directly or indirectly by producing several metabolites. In this review, we mainly discuss a newly identified gut microbiota-dependent metabolite, trimethylamine N-oxide (TMAO), which appears to participate in the pathologic processes of HF and can serve as an early warning marker to identify individuals who are at the risk of disease progression. We also discuss the potential of the gut-TMAO-HF axis as a new target for HF treatment and highlight the current controversies and potentially new and exciting directions for future research.

Probiotics, Prebiotics and Synbiotics-A Promising Strategy in Prevention and Treatment of Cardiovascular Diseases?

Recent evidence suggests that probiotics, prebiotics and synbiotics may serve as important dietary components in the prevention (especially) and treatment of cardiovascular diseases (CVD), but the recommendations for their use are often based on brief reports and small clinical studies. This review evaluates the current literature on the correlation between CVD and probiotics, prebiotics and synbiotics. Although research on probiotics, prebiotics and synbiotics has grown exponentially in recent years, particularly regarding the effect of probiotics on CVD, their mechanisms have not been clearly defined. It has been proposed that probiotics lower cholesterol levels, and may protect against CVD, by increasing bile salt synthesis and bile acid deconjugation. Similar effects have also been observed for prebiotics and synbiotics; however, probiotics also appear to have anti-oxidative, anti-platelet and anti-inflammatory properties. Importantly, probiotics not only have demonstrated effects in vitro and in animal models, but also in humans, where supplementation with probiotics decreases the risk factors of CVD. In addition, the properties of commercial probiotics, prebiotics and synbiotics remain undetermined, and further experimental research is needed before these substances can be used in the prevention and treatment of CVD. In particular, well-designed clinical trials are required to determine the influence of probiotics on trimethylamine-N-oxide (TMAO), which is believed to be a marker of CVDs, and to clarify the long-term effects, and action, of probiotic, prebiotic and synbiotic supplementation in combination with drug therapy (for example, aspirin). However, while it cannot be unequivocally stated whether such supplementation yields benefits in the prevention and treatment of CVDs, it is important to note that clinical studies performed to date have not identified any side-effects to use.

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.

Reduction of intestinal trimethylamine by probiotics ameliorated lipid metabolic disorders associated with atherosclerosis

OBJECTIVES

The purpose of this study was to explore the effect of trimethylamine (TMA)-degrading probiotic agents on trimethylamine oxide (TMAO) and the related lipid metabolism in mice.

METHODS

Ten lipid-lowering strains were detected with TMA-degradation capacity in vitro. After probiotic intervention for the mice on a high-choline diet, TMA content in cecum and TMA and TMAO in serum was explored, as well as the expression of key gene flavin-containing monooxygenase 3 (FMO3) of the TMA-TMAO metabolism. The expression of genes related to the lipid metabolism was also investigated by real-time polymerase chain reaction and Western blot. Finally, the colonization of functional strains in the intestine were examined.

RESULTS

Five of 10 lipid-lowering strains effectively degraded TMA in vitro, and the TMA level in the cecum of mice were reduced after probiotic intervention. TMA level and TMAO in serum were also significantly reduced by the strains (P < 0.05), but not due to the regulation of FMO3. Probiotic agents could improve the lipid metabolism by acting on the Farnesoid X receptor and cholesterol 7-alpha hydroxy-lase. Among the strains, Bifidobacterium animalis subsp. lactis F1-3-2 showed the most prominent performance and colonized in the cecum of mice.

CONCLUSIONS

Bif. animalis subsp. lactis F1-3-2 could be colonized in the cecum, and might directly degrade TMA or change the structure of intestinal flora. The strain had an effect on TMA and TMAO levels in vivo by decreasing cecum TMA. The strain was demonstrated to participate in the TMA-TMAO regulation, improve the lipid metabolism, and alleviate atherosclerosis caused by TMAO. However, FMO3 had not changed in this process, and needs further study.

Endothelial Function is improved by Inducing Microbial Polyamine Production in the Gut: A Randomized Placebo-Controlled Trial

Recently, it was demonstrated that spermidine-induced autophagy reduces the risk of cardiovascular disease in mice. Intestinal bacteria are a major source of polyamines, including spermidine. We previously reported that the intake of both Bifidobacterium animalis subsp. lactis (Bifal) and arginine (Arg) increases the production of putrescine, a spermidine precursor, in the gut. Here, we investigated the effects of Bifal and Arg consumption on endothelial function in healthy subjects. Healthy individuals with body mass index (BMI) near the maximum value in the “healthy” range (BMI: 25) (n = 44) were provided normal yogurt containing Bifal and Arg (Bifal + Arg YG) or placebo (normal yogurt) for 12 weeks in this randomized, double-blinded, placebo-controlled, parallel-group comparative study. The reactive hyperemia index (RHI), the primary outcome, was measured using endo-peripheral arterial tone (EndoPAT). The change in RHI from week 0 to 12 in the Bifal + Arg YG group was significantly higher than that in the placebo group, indicating that Bifal + Arg YG intake improved endothelial function. At week 12, the concentrations of fecal putrescine and serum putrescine and spermidine in the Bifal + Arg YG group were significantly higher than those in the placebo group. This study suggests that consuming Bifal + Arg YG prevents or reduces the risk of atherosclerosis.

Probiotics: current landscape and future horizons

In recent years there has been a rapid rise in interest for the application of probiotic supplements to act as mediators in health and disease. This appeal is predominantly due to ever-increasing evidence of the interaction of the microbiota and pathophysiological processes of disease within the human host. This narrative review considers the current landscape of the probiotic industry and its research, and discusses current pitfalls in the lack of translation from laboratory science to clinical application. Future considerations into how industry and academia must adapt probiotic research to maximize success are suggested, including more targeted application of probiotic strains dependent on individual capabilities as well as application of multiple advanced analytical technologies to further understand and accelerate microbiome science.

Revisit gut microbiota and its impact on human health and disease

Trillions of microbes have evolved with and continue to live on human beings. With the rapid advances in tools and technology in recent years, new knowledge and insight in cross-talk between the microbes and their hosts have gained. It is the aim of this work to critically review and summarize recent literature reports on the role of microbiota and mechanisms involved in the progress and development of major human diseases, which include obesity, hypertension, cardiovascular disease, diabetes, cancer, Inflammatory Bowel Disease (IBD), gout, depression and arthritis, as well as infant health and longevity.

Protective activities of polysaccharides from Cipangopaludina chinensis against high-fat-diet-induced atherosclerosis via regulating gut microbiota in ApoE-deficient mice

The supplementation of sulfated polysaccharides extracted from C. chinensis slows down the development of atherosclerosis caused by high-fat-diet-induced AS via regulating gut microbiota.

Cross-Talk between Gut Microbiota and Heart via the Routes of Metabolite and Immunity

Considering the prevalence of cardiovascular disease (CVD), significant interest has been focused on the gut microbiota-heart interaction because the gut microbiota has been recognized as a barometer of human health. Dysbiosis, characterized by changes in the gut microbiota in CVD, has been reported in cardiovascular pathologies, such as atherosclerosis, hypertension, and heart failure. Conversely, gut microbiota-derived metabolites, such as trimethylamine/trimethylamine N-oxide (TMA/TMAO), can impact host physiology. Further, bacterial dysbiosis can disturb gut immunity, which increases the risk of acute arterial events. Moreover, studies of germ-free mice have provided evidence that microbiota diversity and the presence of a specific microbe in the gut can affect immune cells in hosts. Therefore, the changes in the composition of the gut microbiota can affect host metabolism and immunity. Importantly, these effects are not only confined to the gut but also spreaded to distal organs. The purpose of the current review is to highlight the complex interplay between the microbiota and CVD via TMAO and different immune cells and discuss the roles of probiotics and nutrition interventions in modulating the intestinal microbiota as novel therapeutic targets of CVD.

Nanocomposite of Half-Fin Anchovy Hydrolysates/Zinc Oxide Nanoparticles Exhibits Actual Non-Toxicity and Regulates Intestinal Microbiota, Short-Chain Fatty Acids Production and Oxidative Status in Mice

The nanocomposite of half-fin anchovy hydrolysates (HAHp) and zinc oxide nanoparticles (ZnO NPs) (named as HAHp(3.0)/ZnO NPs) demonstrated increased antibacterial activity compared to either HAHp(3.0) or ZnO NPs as per our previous studies. Also, reactive oxygen species (ROS) formation was detected in Escherichia coli cells after treatment with HAHp(3.0)/ZnO NPs. The aim of the present study was to evaluate the acute toxicity of this nanocomposite and to investigate its effect on intestinal microbiota composition, short-chain fatty acids (SCFAs) production, and oxidative status in healthy mice. The limit test studies show that this nanoparticle is non-toxic at the doses tested. The administration of HAHp(3.0)/ZnO NPs, daily dose of 1.0 g/kg body weight for 14 days, increased the number of goblet cells in jejunum. High-throughput 16S ribosomal RNA gene sequencing of fecal samples revealed that HAHp(3.0)/ZnO NPs increased Firmicutes and reduced Bacteriodetes abundances in female mice. Furthermore, the microbiota for probiotic-type bacteria, including Lactobacillus and Bifidobacterium, and SCFAs-producing bacteria in the Clostridia class, e.g., Lachnospiraceae_unclassified and Lachnospiraceae_UCG-001, were enriched in the feces of female mice. Increases of SCFAs, especially statistically increased propionic and butyric acids, indicated the up-regulated anti-inflammatory activity of HAHp(3.0)/ZnO NPs. Additionally, some positive responses in liver, like markedly increased glutathione and decreased malonaldehyde contents, indicated the improved oxidative status. Therefore, our results suggest that HAHp(3.0)/ZnO NPs could have potential applications as a safe regulator of intestinal microbiota or also can be used as an antioxidant used in food products.