Probiotic therapy to men with incipient arteriosclerosis initiates increased bacterial diversity in colon: a randomized controlled trial

Short-chain fatty acid levels in stools of patients with inflammatory bowel disease are lower than those in healthy subjects

OBJECTIVE

Short-chain fatty acids (SCFAs) are produced when the microbiota in the large intestine cause fermentation of dietary carbohydrates and fibers. These fatty acids constitute the primary energy source of colon mucosa cells and have a protective effect in patients suffering from inflammatory bowel disease (IBD). This study aimed to compare the SCFA levels in the stools of patients with IBD and healthy controls.

METHOD

Healthy controls and patients with IBD aged 18 and over were included in the study. Stool samples from all patients and healthy controls were collected, and stool acetic acid, propionic acid, and butyric acid levels were measured using a gas chromatography-mass spectrometry measurement method.

RESULTS

In this study, 64 participants were divided into two groups: 34 were in IBD (Crohn disease and ulcerative colitis) and 30 were in healthy control group. When fecal SCFA concentrations of IBD and healthy control groups were compared, a statistically significant difference was observed between them. When the fecal SCFA concentrations of Crohn's disease and ulcerative colitis patients in the IBD group were compared, however, no statistically significant difference was observed between them. Furthermore, when the participants' diet type (carbohydrate-based, vegetable-protein-based and mixed diet) and the number of meals were compared with fecal SCFA concentrations, no statistically significant difference was observed between them.

CONCLUSION

In general, fecal SCFA levels in patients with IBD were lower than those in healthy controls. Moreover, diet type and the number of meals had no effect on stool SCFA levels in patients with IBD and healthy individuals.

Role of the microbiota-gut-heart axis between bile acids and cardiovascular disease

Bile acid (BA) receptors (e.g., farnesoid X-activated receptor, muscarinic receptor) are expressed in cardiomyocytes, endothelial cells, and vascular smooth muscle cells, indicating the relevance of BAs to cardiovascular disease (CVD). Hydrophobic BAs are cardiotoxic, while hydrophilic BAs are cardioprotective. For example, fetal cardiac insufficiency in maternal intrahepatic cholestasis during pregnancy, and the degree of fetal cardiac abnormality, is closely related to the level of hydrophobic BAs in maternal blood and infant blood. However, ursodeoxycholic acid (the most hydrophilic BA) can reverse/prevent these detrimental effects of increased levels of hydrophobic BAs on the heart. The gut microbiota (GM) and GM metabolites (especially secondary BAs) have crucial roles in hypertension, atherosclerosis, unstable angina, and heart failure. Herein, we describe the relationship between CVD and the GM at the BA level. We combine the concept of the "microbiota-gut-heart axis" (MGHA) and postulate the role and mechanism of BAs in CVD development. In addition, the strategies for treating CVD with BAs under the MGHA are proposed.

Role of the intestinal microbiome and its therapeutic intervention in cardiovascular disorder

The gut microbiome is a heterogeneous population of microbes comprising viruses, bacteria, fungi, and protozoa. Such a microbiome is essential for sustaining host equilibrium, and its impact on human health can be altered by a variety of factors such as external variables, social behavior, age, nutrition, and genetics. Gut microbes' imbalances are related to a variety of chronic diseases including cancer, obesity, and digestive disorders. Globally, recent findings show that intestinal microbes have a significant role in the formation of cardiovascular disease (CVD), which is still the primary cause of fatalities. Atherosclerosis, hypertension, diabetes, inflammation, and some inherited variables are all cardiovascular risk variables. However, studies found correlations between metabolism, intestinal flora, and dietary intake. Variations in the diversity of gut microbes and changes in their activity are thought to influence CVD etiology. Furthermore, the gut microbiota acts as an endocrine organ, producing bioactive metabolites such as TMA (trimethylamine)/TMAO (trimethylamine N-oxide), SCFA (short-chain fatty acids), and bile acids, which have a substantial impact on host wellness and disease by multiple mechanisms. The purpose of this overview is to compile current evidence highlighting the intricate links between gut microbiota, metabolites, and the development of CVD. It focuses on how intestinal dysbiosis promotes CVD risk factors such as heart failure, hypertension, and atherosclerosis. This review explores the normal physiology of intestinal microbes and potential techniques for targeting gut bacteria for CVD treatment using various microbial metabolites. It also examines the significance of gut bacteria in disease treatment, including supplements, prebiotics, probiotics, antibiotic therapies, and fecal transplantation, which is an innovative approach to the management of CVD. As a result, gut bacteria and metabolic pathways become increasingly attractive as potential targets for CVD intervention.

Microbiota Metabolites and Immune Regulation Affect Ischemic Stroke Occurrence, Development, and Prognosis

The gut microbiota are not only related to the development and occurrence of digestive system disease, but also have a bidirectional relationship with nervous system diseases via the microbiota-gut-brain axis. At present, correlations between the gut microbiota and neurological diseases, including stroke, are one of the focuses of investigation and attention in the medical community. Ischemic stroke (IS) is a cerebrovascular disease accompanied by focal neurological deficit or central nervous system injury or death. In this review, we summarize the contemporary latest research on correlations between the gut microbiota and IS. Additionally, we discuss the mechanisms of gut microbiota implicated in IS and related to metabolite production and immune regulation. Moreover, the factors of gut microbiota that affecting IS occurrence, and research implicating the gut microbiota as potential therapeutic targets for IS, are highlighted. Our review highlights the evidential relationships and connections between the gut microbiota and IS pathogenesis and prognosis.

Gut microbiome-mediated mechanisms in aging-related diseases: are probiotics ready for prime time?

Chronic low-grade inflammation affects health and is associated with aging and age-related diseases. Dysregulation of the gut flora is an important trigger for chronic low-grade inflammation. Changes in the composition of the gut flora and exposure to related metabolites have an effect on the inflammatory system of the host. This results in the development of crosstalk between the gut barrier and immune system, contributing to chronic low-grade inflammation and impairment of health. Probiotics can increase the diversity of gut microbiota, protect the gut barrier, and regulate gut immunity, thereby reducing inflammation. Therefore, the use of probiotics is a promising strategy for the beneficial immunomodulation and protection of the gut barrier through gut microbiota. These processes might positively influence inflammatory diseases, which are common in the elderly.

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

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

Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases

Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.

The gut microbiota-artery axis: A bridge between dietary lipids and atherosclerosis?

Atherosclerotic cardiovascular disease is one of the major leading global causes of death. Growing evidence has demonstrated that gut microbiota (GM) and its metabolites play a pivotal role in the onset and progression of atherosclerosis (AS), now known as GM-artery axis. There are interactions between dietary lipids and GM, which ultimately affect GM and its metabolites. Given these two aspects, the GM-artery axis may play a mediating role between dietary lipids and AS. Diets rich in saturated fatty acids (SFAs), omega-6 polyunsaturated fatty acids (n-6 PUFAs), industrial trans fatty acids (TFAs), and cholesterol can increase the levels of atherogenic microbes and metabolites, whereas monounsaturated fatty acids (MUFAs), ruminant TFAs, and phytosterols (PS) can increase the levels of antiatherogenic microbes and metabolites. Actually, dietary phosphatidylcholine (PC), sphingomyelin (SM), and omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been demonstrated to affect AS via the GM-artery axis. Therefore, that GM-artery axis acts as a communication bridge between dietary lipids and AS. Herein, we will describe the molecular mechanism of GM-artery axis in AS and discuss the complex interactions between dietary lipids and GM. In particular, we will highlight the evidence and potential mechanisms of dietary lipids affecting AS via GM-artery axis.

Intratumoral microbiome impacts immune infiltrates in tumor microenvironment and predicts prognosis in esophageal squamous cell carcinoma patients

Background

Different intratumoral microbiotaexist in different tumors and play a crucial function in carcinogenesis. However, whether they impact clinical outcomes in esophageal squamous cell carcinoma (ESCC) and their mechanism remain unclear.

Methods

16S rDNA amplicon sequencing was performed on surgically resected samples from 98 ESCC patients to analyze intratumoral microbiome abundance and composition. Multiplex fluorescent immunohistochemistry staining was used to profile the phenotypes of immune infiltrates in the tumor microenvironment (TME).

Results

Patients with higher intratumoral Shannon index had significantly worse surgical outcomes. When patients were divided into short-term survivors and long-term survivors based on the median survival time, both intratumoral alpha-diversity and beta-diversity were found to be significantly inconsistent, and the relative abundance of Lactobacillus and Leptotrichia emerged as the two microorganisms that probably influenced the survival of ESCC patients. Only Lactobacillus in ESCC was validated to significantly worsen patients' prognoses and to be positively correlated with the Shannon index. Multivariate analysis revealed that the intratumoral Shannon index, the relative abundance of Lactobacillus, and the pathologic tumor-node-metastasis (pTNM) stage were independently associated with patients' overall survival. Furthermore, the relative abundance of both Lactobacillus and Shannon index was positively correlated with the proportions of PD-L1⁺ epithelial cells (ECs) and tumor-associated macrophages (TAMs). The Shannon index was negatively correlated with the proportions of natural killer (NK) cells in the TME.

Conclusions

A high abundance of intratumoral Lactobacillus and bacterial alpha-diversity was associated with the formation of the immunosuppressive TME and predicted poor long-term survival in ESCC patients.

Gut Microbiota and Cardiovascular System: An Intricate Balance of Health and the Diseased State

Gut microbiota encompasses the resident microflora of the gut. Having an intricate relationship with the host, it plays an important role in regulating physiology and in the maintenance of balance between health and disease. Though dietary habits and the environment play a critical role in shaping the gut, an imbalance (referred to as dysbiosis) serves as a driving factor in the occurrence of different diseases, including cardiovascular disease (CVD). With risk factors of hypertension, diabetes, dyslipidemia, etc., CVD accounts for a large number of deaths among men (32%) and women (35%) worldwide. As gut microbiota is reported to have a direct influence on the risk factors associated with CVDs, this opens up new avenues in exploring the possible role of gut microbiota in regulating the gross physiological aspects along the gut-heart axis. The present study elaborates on different aspects of the gut microbiota and possible interaction with the host towards maintaining a balance between health and the occurrence of CVDs. As the gut microbiota makes regulatory checks for these risk factors, it has a possible role in shaping the gut and, as such, in decreasing the chances of the occurrence of CVDs. With special emphasis on the risk factors for CVDs, this paper includes information on the prominent bacterial species (Firmicutes, Bacteriodetes and others) towards an advance in our understanding of the etiology of CVDs and an exploration of the best possible therapeutic modules for implementation in the treatment of different CVDs along the gut-heart axis.

Lactiplantibacillus plantarum 299v supplementation modulates β-cell ER stress and antioxidative defense pathways and prevents type 1 diabetes in gluten-free BioBreeding rats

The increasing incidence of Type 1 diabetes has coincided with the emergence of the low-fiber, high-gluten Western diet and other environmental factors linked to dysbiosis. Since Lactiplantibacillus plantarum 299 v (Lp299v) supplementation improves gut barrier function and reduces systemic inflammation, we studied its effects in spontaneously diabetic DRlyp/lyp rats provided a normal cereal diet (ND) or a gluten-free hydrolyzed casein diet (HCD). All rats provided ND developed diabetes (62.5±7.7 days); combining ND with Lp299v did not improve survival. Diabetes was delayed by HCD (72.2±9.4 days, p = .01) and further delayed by HCD+Lp299v (84.9±14.3 days, p < .001). HCD+Lp299v pups exhibited increased plasma propionate and butyrate levels, which correlated with enriched fecal Bifidobacteriaceae and Clostridiales taxa. Islet transcriptomic and histologic analyses at 40-days of age revealed that rats fed HCD expressed an autophagy profile, while those provided HCD+Lp299v expressed ER-associated protein degradation (ERAD) and antioxidative defense pathways, including Nrf2. Exposing insulinoma cells to propionate and butyrate promoted the antioxidative defense response but did not recapitulate the HCD+Lp299v islet ERAD transcriptomic profile. Here, both diet and microbiota influenced diabetes susceptibility. Moreover, Lp299v supplement modulated antioxidative defense and ER stress responses in β-cells, potentially offering a new therapeutic direction to thwart diabetes progression and preserve insulin secretion.

Emerging computational paradigms to address the complex role of gut microbial metabolism in cardiovascular diseases

The human gut microbiota and its associated perturbations are implicated in a variety of cardiovascular diseases (CVDs). There is evidence that the structure and metabolic composition of the gut microbiome and some of its metabolites have mechanistic associations with several CVDs. Nevertheless, there is a need to unravel metabolic behavior and underlying mechanisms of microbiome-host interactions. This need is even more highlighted when considering that microbiome-secreted metabolites contributing to CVDs are the subject of intensive research to develop new prevention and therapeutic techniques. In addition to the application of high-throughput data used in microbiome-related studies, advanced computational tools enable us to integrate omics into different mathematical models, including constraint-based models, dynamic models, agent-based models, and machine learning tools, to build a holistic picture of metabolic pathological mechanisms. In this article, we aim to review and introduce state-of-the-art mathematical models and computational approaches addressing the link between the microbiome and CVDs.

Gut Microbiota Modulation as a Novel Therapeutic Strategy in Cardiometabolic Diseases

The human gut harbors microbial ecology that is in a symbiotic relationship with its host and has a vital function in keeping host homeostasis. Inimical alterations in the composition of gut microbiota, known as gut dysbiosis, have been associated with cardiometabolic diseases. Studies have revealed the variation in gut microbiota composition in healthy individuals as compared to the composition of those with cardiometabolic diseases. Perturbation of host-microbial interaction attenuates physiological processes and may incite several cardiometabolic disease pathways. This imbalance contributes to cardiometabolic diseases via metabolism-independent and metabolite-dependent pathways. The aim of this review was to elucidate studies that have demonstrated the complex relationship between the intestinal microbiota as well as their metabolites and the development/progression of cardiometabolic diseases. Furthermore, we systematically itemized the potential therapeutic approaches for cardiometabolic diseases that target gut microbiota and/or their metabolites by following the pathophysiological pathways of disease development. These approaches include the use of diet, prebiotics, and probiotics. With the exposition of the link between gut microbiota and cardiometabolic diseases, the human gut microbiota therefore becomes a potential therapeutic target in the development of novel cardiometabolic agents.

The effect of probiotic and synbiotic supplementation on lipid parameters among patients with cardiometabolic risk factors: a systematic review and meta-analysis of clinical trials

Although the available evidence emphasizes the beneficial effects of probiotics in normalizing various cardiometabolic markers, there is still substantial uncertainty in this regard. Thus, we set out to determine the effect sizes of probiotics on blood lipid parameters more coherently. A systematic literature search of the Medline (PubMed) and Scopus databases was conducted from inception to February 12, 2021, applying both MeSH terms and free text terms to find the relevant randomized controlled trials (RCTs). The meta-analysis was conducted based on a random-effect model to calculate the mean effect sizes demonstrated as weighted mean differences (WMD) and the 95% confidence intervals (95%CI). To explore the heterogeneity, the Cochrane Chi-squared test, and analysis of Galbraith plots were performed. Meta-analysis of data from 40 RCTs (n = 2795) indicated a significant decrease in serum/plasma triglyceride (WMD (95%CI)    -12.26 (-17.11- -7.41) mg/dL; P-value <0.001; I2 (%)= 29.9; P heterogeneity = 0.034)), total cholesterol (with high heterogeneity) (WMD (95%CI)    -8.43 (-11.90- -4.95) mg/dL; P-value <0.001; I2 (%) =56.8; P heterogeneity < 0.001), LDL-C (WMD (95%CI)    -5.08 (-7.61, -2.56) mg/dL; P-value <0.001; I2 (%) =42.7; P heterogeneity =0.002), and HDL-C (with high heterogeneity) (WMD (95%CI)    1.14 (0.23, 2.05) mg/dL; P-value =0.014; I2 (%) = 59.8; P heterogeneity < 0.001) following receiving probiotic/synbiotic supplements. Collectively, the current preliminary evidence supports the effectiveness of probiotics/synbiotics in improving dyslipidemia and various lipid parameters more prominently among subjects with hyperlipidemia, diabetes, and metabolic syndrome. However, large and well conducted RCTs are required to provide further convincing support for these results.

The Gut Microbiota (Microbiome) in Cardiovascular Disease and Its Therapeutic Regulation

In the last two decades, considerable interest has been shown in understanding the development of the gut microbiota and its internal and external effects on the intestine, as well as the risk factors for cardiovascular diseases (CVDs) such as metabolic syndrome. The intestinal microbiota plays a pivotal role in human health and disease. Recent studies revealed that the gut microbiota can affect the host body. CVDs are a leading cause of morbidity and mortality, and patients favor death over chronic kidney disease. For the function of gut microbiota in the host, molecules have to penetrate the intestinal epithelium or the surface cells of the host. Gut microbiota can utilize trimethylamine, N-oxide, short-chain fatty acids, and primary and secondary bile acid pathways. By affecting these living cells, the gut microbiota can cause heart failure, atherosclerosis, hypertension, myocardial fibrosis, myocardial infarction, and coronary artery disease. Previous studies of the gut microbiota and its relation to stroke pathogenesis and its consequences can provide new therapeutic prospects. This review highlights the interplay between the microbiota and its metabolites and addresses related interventions for the treatment of CVDs.

Effect of Oral Intake of Lactiplantibacillus plantarum APsulloc 331261 (GTB1TM) on Diarrhea-Predominant Irritable Bowel Syndrome: A Randomized, Double-Blind, Placebo-Controlled Study

Irritable bowel syndrome (IBS) causes intestinal discomfort, gut dysfunction, and poor quality of life. This randomized, double-blind placebo-controlled trial evaluated the efficacy of Lactiplantibacillus (Lp., formerly Lactobacillus) plantarum APsulloc 331261 (GTB1^TM) from green tea leaves in participants with diarrhea-predominant irritable bowel syndrome (IBS-D). Twenty-seven participants meeting the Rome IV diagnostic criteria were randomized for GTB1 or placebo ingestion for four weeks and follow-up for two weeks. The efficacy endpoints included adequate global relief of symptoms, assessment of intestinal discomfort symptom severity and frequency, stool frequency, satisfaction, and fecal microbiome abundance. Of all participants, 94.4% and 62.5% reported global relief of symptoms in the GTB1 and placebo groups, respectively, with significant differences (p = 0.037). GTB1 significantly reduced the severity and frequency of abdominal pain, bloating, and feeling of incomplete evacuation. The frequencies of diarrhea were decreased −45.89% and −26.76% in the GTB1 and placebo groups, respectively (p = 0.045). Hence, GTB1 ingestion improved IBS-D patient quality of life. After four weeks treatment, the relative abundance of Lactobacillus was higher in the GTB1 than in the placebo group (p = 0.010). Our results showed that GTB1 enhanced intestinal discomfort symptoms, defecation consistency, quality of life, beneficial microbiota, and overall intestinal health.

The Effects of Probiotics on Inflammation, Endothelial Dysfunction, and Atherosclerosis Progression: A Mechanistic Overview

INTRODUCTION

The relationship between the intestinal microbiota dysbiosis, inflammation, and cardiovascular disorders (CVDs) has become evident, based on a growing body of literature from animal models and human studies. On the other hand, probiotics are believed to have promising effects on modifying dysbiosis and protecting against CVDs.

OBJECTIVE

This narrative review provides an overview of the link between gut microbiota, inflammation, endothelial dysfunction, and atherosclerosis. The influences of probiotic supplementation on biomarkers contributing to these conditions as the primary underlying risk factors for developing CVDs are also discussed.

METHODS

An up-to-date review was performed of the available evidence from experimental studies, clinical trials, and meta-analyses, considering their challenges and limitations. It also aimed to provide mechanistic insight into the likely mechanisms of probiotics that could prevent atherosclerosis initiation and progression.

RESULTS

Probiotic supplementation seems to be associated with reduced levels of inflammation and oxidative stress biomarkers (C-reactive protein, tumour necrosis factor-α, interleukin (IL)-6, IL-12, and malondialdehyde). Further, these agents might enhance antioxidant factors (IL-10, total antioxidant status, total antioxidant capacity, glutathione, and nitric oxide). Probiotics also appear to improve intestinal barrier integrity, reduce leakage of harmful metabolites (e.g., lipopolysaccharides), inhibit pro-inflammatory signalling pathways, and possibly suppress the formation of trimethylamine/trimethylamine oxide. Probiotics have also been found to enhance endothelial function and halter thrombosis.

CONCLUSION

The current clinical evidence underlines belief that probiotics might be associated with reduced levels of inflammation biomarkers. Experimental evidence reports that the beneficial effects of probiotics seem to be mainly imposed by triggering the secretion of short-chain fatty acids and bile acids, in addition to suppressing the NF-κB signalling pathway. However, the current studies are still in their infancy and it is of high priority to design further research on the topic.

Administration of probiotics to healthy volunteers: effects on reactivity of intestinal mucosa and systemic leukocytes

Background

Oral administration of health-promoting bacteria is increasingly used in clinical practise. These bacteria have anti-inflammatory characteristics and modulate the immune system without major reported side effects. The mechanisms of action are not yet fully defined. Our aim was to study systemic effects of probiotics by measurements of leukocytes as well as local effects on rectal mucosal biopsies after adding a standardized inflammatory stimulus in vitro.

Methods

Fourteen healthy subjects were randomized to receive 10¹⁰ colony forming units/day orally of the probiotic strain Lactiplantibacillus plantarum 299 (Lp299), n = 7, or Bifidobacterium infantis CURE21 (CURE21), n = 7, for six weeks. Rectal biopsies were taken before and after ingestion of either probiotic strain product, for stimulation in vitro with tumour necrosis factor alpha (TNF-α) at 10 and 100 ng/ml respectively up to 8 h. Blood tests were sampled before and after treatment. Lactate dehydrogenase (LDH) confirmed viable tissue.

Results

Composition of the intestinal microbiota was not changed. Systemic leukocytes decreased after administration of CURE21 (P<0.05) and Lp299 (P<0.01). Levels of the pro-inflammatory cytokine IL-6 in rectal mucosa after stimulation with TNF-α were attenuated after ingestion of Lp299. No effect was seen with CURE21.

Conclusions

Administration of these probiotic strains to healthy humans show both a systemic and local reduction of inflammatory response by lowering leukocyte counts, and for Lp299 IL-6 levels in rectal mucosa. Probiotics may play an important role in the reduction of inflammatory responses expected after trauma during surgery or after pelvic irradiation.

Trial registration Clinical Trials, registration number NCT01534572, retrospectively registered (http://www.clinicaltrials.gov).

Impact of Gut Microbiota on the Risk of Cardiometabolic Diseases Development

Obesity is a multifactorial disease that leads to excessive adipose tissue accumulation, mainly visceral fat. Importance and prevalence of obesity has increased significantly in recent decades all over the world. Until now, the pandemic of obesity has been associated more to lifestyle changes: excessive eating and low physical activity. In recent years, special attention has been paid to studying of composition and functions of intestinal microbiota as major factor in development of obesity and related comorbidities, such as hypertension, cardiac ischemia, heart failure and others. It is proved that gut microbiota affects extraction, accumulation and consumption of energy derived from food, lipid metabolism and immune response. It is also revealed that composition of the microbiota is different in thin and obese people. Thus, study of the relationship between intestinal microbiota composition and risk factors for cardiovascular diseases, in particular obesity, is an actual task. The purpose of this review is analyzing of literature about assessment of relationship between composition and functions of intestinal microbiota in the diagnostics, prevention and treatment of obesity and cardiovascular diseases.

Probiotic Supplements: Their Strategies in the Therapeutic and Prophylactic of Human Life-Threatening Diseases

Chronic diseases and viral infections have threatened human life over the ages and constitute the main reason for increasing death globally. The rising burden of these diseases extends to negatively affecting the economy and trading globally, as well as daily life, which requires inexpensive, novel, and safe therapeutics. Therefore, scientists have paid close attention to probiotics as safe remedies to combat these morbidities owing to their health benefits and biotherapeutic effects. Probiotics have been broadly adopted as functional foods, nutraceuticals, and food supplements to improve human health and prevent some morbidity. Intriguingly, recent research indicates that probiotics are a promising solution for treating and prophylactic against certain dangerous diseases. Probiotics could also be associated with their essential role in animating the immune system to fight COVID-19 infection. This comprehensive review concentrates on the newest literature on probiotics and their metabolism in treating life-threatening diseases, including immune disorders, pathogens, inflammatory and allergic diseases, cancer, cardiovascular disease, gastrointestinal dysfunctions, and COVID-19 infection. The recent information in this report will particularly furnish a platform for emerging novel probiotics-based therapeutics as cheap and safe, encouraging researchers and stakeholders to develop innovative treatments based on probiotics to prevent and treat chronic and viral diseases.

Cardiovascular Health and The Intestinal Microbial Ecosystem: The Impact of Cardiovascular Therapies on The Gut Microbiota

It has become evident over the past several years that the intestinal microbial ecosystem plays a critical role in the development and prevention of cardiovascular diseases (CVDs) and other metabolic disorders, such as hypertension, obesity, diabetes mellitus, and metabolic syndrome. The intestinal microbiota ecosystem functions as a major virtual endocrine organ that interacts and responds to molecules' signals within the host. Several meta-organismal pathways are involved in the gut-host interaction, including trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFA). Host phenotype and cardiovascular diseases (CVDs) varying from hypertension, insulin resistance, and obesity to more specific inflammatory processes, such as atherosclerosis and hypercoagulability, have shown to be affected by the gut-host interaction. Additionally, several studies that involved animals and humans demonstrated a striking connection between the development of new CVDs and an imbalance in the gut microbiota composition along with the presence of their derived metabolites. Through this review article, we aim to evaluate the role of the normal gut microbiota ecosystem, its association with CVDs, effects of the therapies used to control and manage CVDs in the gut microbiota environment and explore potential therapeutic interventions to amplify disease outcomes in patients with CVDs.

Lactiplantibacillus plantarum 299v (LP299V®): three decades of research

This review aims to provide a comprehensive overview of the in vitro, animal, and clinical studies with the bacterial strain Lactiplantibacillus plantarum 299v (L. plantarum 299v; formerly named Lactobacillus plantarum 299v) published up until June 30, 2020. L. plantarum 299v is the most documented L. plantarum strain in the world, described in over 170 scientific publications out of which more than 60 are human clinical studies. The genome sequence of L. plantarum 299v has been determined and is available in the public domain (GenBank Accession number: NZ_LEAV01000004). The probiotic strain L. plantarum 299v was isolated from healthy human intestinal mucosa three decades ago by scientists at Lund University, Sweden. Thirty years later, a wealth of data coming from in vitro, animal, and clinical studies exist, showing benefits primarily for gastrointestinal health, such as reduced flatulence and abdominal pain in patients with irritable bowel syndrome (IBS). Moreover, several clinical studies have shown positive effects of L. plantarum 299v on iron absorption and more recently also on iron status. L. plantarum 299v is safe for human consumption and does not confer antibiotic resistance. It survives the harsh conditions of the human gastrointestinal tract, adheres to mannose residues on the intestinal epithelial cells and has in some cases been re-isolated more than ten days after administration ceased. Besides studying health benefits, research groups around the globe have investigated L. plantarum 299v in a range of applications and processes. L. plantarum 299v is used in many different food applications as well as in various dietary supplements. In a freeze-dried format, L. plantarum 299v is robust and stable at room temperature, enabling long shelf-lives of consumer healthcare products such as capsules, tablets, or powder sachets. The strain is patent protected for a wide range of indications and applications worldwide as well as trademarked as LP299V^®.

Lactobacillus plantarum Lp62 exerts probiotic effects against Gardnerella vaginalis ATCC 49154 in bacterial vaginosis

The severe side-effects elicited by conventional antibiotic therapy and the recurrence of Bacterial vaginosis-associated bacteria and bacterial resistance have led to the development of novel alternative therapies, among which genital probiotics are widely used. In this study, we aimed to evaluate the antimicrobial activities of Lactobacillus plantarum Lp62 and its supernatant against Gardnerella vaginalis, using both in vitro and in vivo approaches. In vitro assays were used to evaluate the viability of the strain and the antimicrobial activities of the supernatant in different pH ranges. An in vivo assay was performed on female BALB/c mice, wherein the animals were divided into eight groups: four control groups and four treated groups (for curative and preventive therapies). After infecting and treating the mice, the animals were killed to quantify the bacterial load using qPCR, evaluate leucocyte cellular response, determine vaginal cytokine levels and perform cytokine tissue gene expression. Our analyses revealed significant activity of the strain and its supernatant against G. vaginalis. Preliminary in vitro tests showed that the strain grew with equal efficiency in different pH ranges. Meanwhile, the presence of halo and inhibition of pathogen growth established the significant activity of the supernatant against G. vaginalis. We observed that both micro-organisms are resident bacteria of mouse microbiota and that the lactobacilli population growth was affected by G. vaginalis and vice versa. We also observed that the treated groups, with their low bacterial load, absence of leucocyte recruitment, reduced cytokine levels in the vaginal lavage and normalized cytokine gene expression, successfully controlled the infection.

Gut Microbiota and Cardiovascular Diseases: A Critical Review

The human intestine contains the largest and most diverse ecosystem of microbes. The main function of the intestinal bacterial flora is to limit the growth of potentially pathogenic microorganisms. However, the intestinal microbiota is increasingly emerging as a risk factor for the development of cardiovascular disease (CVD). The gut microbiota-derived metabolites, such as short-chain fatty acids, trimethylamine-N-oxide, bile acids, and polyphenols play a pivotal role in maintaining healthy cardiovascular function, and when dysregulated, can potentially lead to CVD. In particular, changes in the composition and diversity of gut microbiota, known as dysbiosis, have been associated with atherosclerosis, hypertension, and heart failure. Nonetheless, the underlying mechanisms remain yet to be fully understood. Therefore, the microbiota and its metabolites have become a new therapeutic target for the prevention and treatment of CVD. In addition to a varied and balanced diet, the use of prebiotic and probiotic treatments or selective trimethylamine-N-oxide inhibitors could play a pivotal role in the prevention of CVD, especially in patients with a high metabolic risk.

Probiotics/ prebiotics in viral respiratory infections: implication for emerging pathogens

BACKGROUND

Viral respiratory infections could result in perturbation of the gut microbiota due to a probable cross-talk between lungs and gut microbiota. This can affect the pulmonary health and the gastrointestinal system.

OBJECTIVE

This review aimed to discuss the impact of probiotics/ prebiotics and supplements on the prevention and treatment of respiratory infections, especially emerging pathogens.

METHODS

The data were searched were searched in PubMed, Scopus, Google Scholar, Google Patents, and The Lens-Patent using keywords of probiotics and viral respiratory infections in the title, abstract, and keywords.

RESULT

Probiotics consumption could decrease the susceptibility to viral respiratory infections, such as COVID-19 and simultaneously enhance vaccine efficiency in infectious disease prevention through the immune system enhancement. Probiotics improve the gut microbiota and the immune system via regulating the innate system response and production of anti-inflammatory cytokines. Moreover, treatment with probiotics contributes to the intestinal homeostasis restitution under antibiotic pressure and decreasing the risk of secondary infections due to viral respiratory infections. Probiotics present varied performances in different conditions; thus, promoting their efficacy through combining with supplements (prebiotics, postbiotics, nutraceuticals, berberine, curcumin, lactoferrin, minerals, and vitamins) is important. Several supplements reported to enhance the probiotics' efficacy and their mechanisms as well as probiotics related patents are summarized in this review. Using nanotechnology and microencapsulation techniques can also improve probiotics efficiency.

CONCLUSION

Given the global challenge of COVID-19, probiotic/prebiotic and following nutritional guidelines should be regarded seriously. Additionally, their role as an adjuvant in vaccination for immune response augmentation needs attention.

Immune response and gut microbiota of mice on a diet mimicking eating habits of elderly with risk of malnutrition development

The number of elderlies is increasing but prevalence of malnutrition has been reported. The aim of the study was to determine the significance of short-term nutritional deficiencies in mice. Immune status was assessed through flow cytometry of leucocytes in Peyer's patches (PP) and mesenteric lymph nodes (MLN), and intestinal microbiota was evaluated by terminal restriction fragment length polymorphism (T-RFLP). C57BL/6NCrl mice fed standard diet (StD) or experimental diet high in fat, and low in carbohydrates, protein, fibre, vitamins, and minerals (ExpD) for 2 or 4 weeks. ExpD-animals gained less weight, increased liver lipids, and developed splenomegaly. Diet affected regulatory T-cells, gut homing receptors and TLR2 and TLR4 in PP and MLN and the microbiota was influenced. Partial least squares models on flow cytometry- and T-RFLP data demonstrated correlations between microbial communities and immune phenotyping. Our model shows similarities to malnourished elderly and interactions between intestinal bacteria and the immune system.

Gut microbiota in coronary artery disease: a friend or foe?

There is a growing interest in the role of gut microbiota in the pathophysiology of several diseases, including coronary artery diseases (CAD). Gut microorganisms may produce beneficial effects in myocardial ischemia either directly in the form of exogenous administration or indirectly by acting on fiber-rich food to produce important cardioprotective components. The harmful effects of gut microbiota in CAD are due to alteration in their composition with a significant decrease in Bacteroidetes and an increase in Firmicutes, Escherichia, Shigella, and Enterococcus. The altered microbiota may produce potentially toxic metabolites, including trimethylamine-N-oxide (TMAO). Indeed, the fasting plasma levels of TMAO are directly correlated to increased risk of major cardiovascular events in CAD patients, and it is proposed as a potential biomarker to predict the onset of major cardiovascular events. It is concluded that the change in the composition of gut microbiota in CAD patients may predispose to more harmful effects. However, exogenous delivery of probiotics may overcome the detrimental effects of myocardial ischemia.

Therapeutic potential of natural products against atherosclerosis: Targeting on gut microbiota

Gut microbiota (GM) has emerged as an essential and integral factor for maintaining human health and affecting pathological outcomes. Metagenomics and metabolomics characterization have furthered gut metagenome's understanding and unveiled that deviation of specific GM community members and GM-dependent metabolites imbalance orchestrate metabolic or cardiovascular diseases (CVDs). Restoring GM ecosystem with nutraceutical supplements keenly prebiotics and probiotics relatively decreases CVDs incidence and overall mortality. In Atherosclerosis, commensal and pathogenic gut microbes correlate with atherogenesis events. GM-dependent metabolites-trimethylamine N-oxide and short-chain fatty acids regulate atherosclerosis-related metabolic processes in opposite patterns to affect atherosclerosis outcomes. Therefore, GM might be a potential therapeutic target for atherosclerosis. In atherogenic animal models, natural products with cardioprotective properties could modulate the GM ecosystem by revitalizing healthier GM phylotypes and abrogating proatherogenic metabolites, paving future research paths for clinical therapeutics.

Gut microbes in cardiovascular diseases and their potential therapeutic applications

Microbial ecosystem comprises a complex community in which bacteria interact with each other. The potential roles of the intestinal microbiome play in human health have gained considerable attention. The imbalance of gut microbial community has been looked to multiple chronic diseases. Cardiovascular diseases (CVDs) are leading causes of morbidity worldwide and are influenced by genetic and environmental factors. Recent advances have provided scientific evidence that CVD may also be attributed to gut microbiome. In this review, we highlight the complex interplay between microbes, their metabolites, and the potential influence on the generation and development of CVDs. The therapeutic potential of using intestinal microbiomes to treat CVD is also discussed. It is quite possible that gut microbes may be used for clinical treatments of CVD in the near future.

Diversity of Gut Microbiota and Bifidobacterial Community of Chinese Subjects of Different Ages and from Different Regions

Gut microbiota composition and functionality are closely linked to host health. In this study, the fecal microbiota and bifidobacterial communities of 111 healthy volunteers from four regions of China of varying age profiles (Child, 1–5 years; Young, 18–50 years; Elder, 60–80 years; Longevity, ≥90 years) were investigated via high-throughput sequencing. Canonical analysis revealed that the gut microbiota, as well as bifidobacteria profiles of the subjects, clustered according to their regions and age. Eight genera were shared among all subjects, however, certain genera distributed differently in subjects grouped by region and age. Faecalibacterium was enriched in samples from Zhongxiang, unclassified Ruminococcaceae and Christensenellaceae were enriched in the Longevity group, and Bifidobacterium was enriched in Child. Within Bifidobacterium, B. longum was the most abundant species in almost all samples except for Child, in which B. pseudocatenulatum was the most abundant. Additionally, the abundances of B. adolescentis and B. dentium were lower in Child. In conclusion, our results suggest that geography and age affect the structure of the gut microbiota, as well as Bifidobacterium composition, and this variation may greatly associate with the metabolic and immune changes that occur during the process of aging.

Role of gut microbiota in cardiovascular diseases

The human gut is colonized by a community of microbiota, primarily bacteria, that exist in a symbiotic relationship with the host. Intestinal microbiota-host interactions play a critical role in the regulation of human physiology. Deleterious changes to the composition of gut microbiota, referred to as gut dysbiosis, has been linked to the development and progression of numerous diseases, including cardiovascular disease (CVD). Imbalances in host-microbial interaction impair homeostatic mechanisms that regulate health and can activate multiple pathways leading to CVD risk factor progression. Most CVD risk factors, including aging, obesity, dietary patterns, and a sedentary lifestyle, have been shown to induce gut dysbiosis. Dysbiosis is associated with intestinal inflammation and reduced integrity of the gut barrier, which in turn increases circulating levels of bacterial structural components and microbial metabolites, including trimethylamine-N-oxide and short-chain fatty acids, that may facilitate the development of CVD. This article reviews the normal function and composition of the gut microbiome, mechanisms leading to the leaky gut syndrome, its mechanistic link to CVD and potential novel therapeutic approaches aimed towards restoring gut microbiome and CVD prevention. As CVD is the leading cause of deaths globally, investigating the gut microbiota as a locus of intervention presents a novel and clinically relevant avenue for future research.

The Gut Microbiota and Its Implication in the Development of Atherosclerosis and Related Cardiovascular Diseases

The importance of gut microbiota in health and disease is being highlighted by numerous research groups worldwide. Atherosclerosis, the leading cause of heart disease and stroke, is responsible for about 50% of all cardiovascular deaths. Recently, gut dysbiosis has been identified as a remarkable factor to be considered in the pathogenesis of cardiovascular diseases (CVDs). In this review, we briefly discuss how external factors such as dietary and physical activity habits influence host-microbiota and atherogenesis, the potential mechanisms of the influence of gut microbiota in host blood pressure and the alterations in the prevalence of those bacterial genera affecting vascular tone and the development of hypertension. We will also be examining the microbiota as a therapeutic target in the prevention of CVDs and the beneficial mechanisms of probiotic administration related to cardiovascular risks. All these new insights might lead to novel analysis and CVD therapeutics based on the microbiota.

Immunomodulatory effect of Syphacia obvelata in treatment of experimental DSS-induced colitis in mouse model

The ability of helminth parasite infections to manipulate the immune system of their host towards T regulatory responses has been proposed to suppress the inflammatory response. The aim of this study was to investigate the protective and therapeutic effect of Syphacia obvelata in the treatment of experimental DSS -induced colitis. 50 male C57BL/6 mice were divided into 5 groups: healthy uninfected controls, DSS colitis, receiving only S. obv, preventive (S. obv + DSS) and therapeutic group (DSS + S.obv). Colitis intensity was investigated by measuring body weight changes, stool consistency/bleeding and colon length. To evaluate the immune responses induced by this nematode, TNF-α, IL-10, IL-17, IFN-γ and expressing of FoxP3⁺ T cells were measured in mesenteric lymph nodes and Peyer’s patches cells. Mice in preventive and therapeutic groups treated with S. obv egg significantly ameliorated the severity of the DSS colitis, indicated by the reduced disease manifestations, improved histopathological scores correlated with the up regulation of Treg responses and down regulation of proinflammatory cytokines. S. obv can prevention and reverse on-going murine DSS colitis. The data suggest that induction of Tregs and change in cytokine profiles during helminthic therapies were responsible for reversed inflammatory events in IBD.

An examination of data from the American Gut Project reveals that the dominance of the genus Bifidobacterium is associated with the diversity and robustness of the gut microbiota

Bifidobacterium and Lactobacillus are beneficial for human health, and many strains of these two genera are widely used as probiotics. We used two large datasets published by the American Gut Project (AGP) and a gut metagenomic dataset (NBT) to analyze the relationship between these two genera and the community structure of the gut microbiota. The meta-analysis showed that Bifidobacterium, but not Lactobacillus, is among the dominant genera in the human gut microbiota. The relative abundance of Bifidobacterium was elevated when Lactobacillus was present. Moreover, these two genera showed a positive correlation with some butyrate producers among the dominant genera, and both were associated with alpha diversity, beta diversity, and the robustness of the gut microbiota. Additionally, samples harboring Bifidobacterium present but no Lactobacillus showed higher alpha diversity and were more robust than those only carrying Lactobacillus. Further comparisons with other genera validated the important role of Bifidobacterium in the gut microbiota robustness. Multivariate analysis of 11,744 samples from the AGP dataset suggested Bifidobacterium to be associated with demographic features, lifestyle, and disease. In summary, Bifidobacterium members, which are promoted by dairy and whole-grain consumption, are more important than Lactobacillus in maintaining the diversity and robustness of the gut microbiota.

The human gut microbiome - a new and exciting avenue in cardiovascular drug discovery

Introduction: Over the past decade, numerous research efforts have identified the gut microbiota as a novel regulator of human metabolic syndrome and cardiovascular disease (CVD). With the elucidation of underlying molecular mechanisms of the gut microbiota and its metabolites, the drug-discovery process of CVD therapeutics might be expedited. Areas covered: The authors describe the evidence concerning the impact of gut microbiota on metabolic disorders and CVD and summarize the current knowledge of the gut microbial mechanisms that underlie CVD with a focus on microbial metabolites. In addition, they discuss the potential impact of the gut microbiota on the drug efficacy of available cardiometabolic therapeutic agents. Most importantly, the authors review the role of the gut microbiome as a promising source of potential drug targets and novel therapeutics for the development of new treatment modalities for CVD. This review also presents the various effective strategies to investigate the gut microbiome for CVD drug-discovery approaches. Expert opinion: With the elucidation of its causative role in cardiometabolic disease and atherosclerosis, the human gut microbiome holds promises as a reservoir of novel potential therapeutic targets as well as novel therapeutic agents, paving a new and exciting avenue in cardiovascular drug discovery.

The Role of the Microbiota in the Diabetic Peripheral Artery Disease

Vascular complications of diabetes mellitus represent a major public health problem. Although many steps forward have been made to define the causes and to find the best possible therapies, the problem remains crucial. In recent years, more and more evidences have defined a link between microbiota and the initiation, promotion, and evolution of atherosclerotic disease, even in the diabetic scenario. There is an urgency to develop the knowledge of modern medicine about the link between gut microbiota and its host's metabolic pathways, and it would be useful to understand and justify the interindividual diversity of clinical disease presentation of diabetic vascular complication even if an optimization of pharmacological treatment has been made or in the case of young patients where hypertension, dyslipidemia, and diabetes are not able to justify a very quick progress of atherosclerotic process. The aim of the present review is to gather all the best available evidence in this regard and to define a new role of the microbiota in this field, from biomarker to possible therapeutic target.

Branched Short-Chain Fatty Acid Isovaleric Acid Causes Colonic Smooth Muscle Relaxation via cAMP/PKA Pathway

BACKGROUND

Isovaleric acid (IVA) is a 5-carbon branched-chain fatty acid present in fermented foods and produced in the colon by bacterial fermentation of leucine. We previously reported that the shorter, straight-chain fatty acids acetate, propionate and butyrate differentially affect colonic motility; however, the effect of branched-chain fatty acids on gut smooth muscle and motility is unknown.

AIMS

To determine the effect of IVA on contractility of colonic smooth muscle.

METHODS

Murine colonic segments were placed in a longitudinal orientation in organ baths in Krebs buffer and fastened to force transducers. Segments were contracted with acetylcholine (ACh), and the effects of IVA on ACh-induced contraction were measured in the absence and presence of tetrodotoxin (TTx) or inhibitors of nitric oxide synthase [L-N-nitroarginine (L-NNA)] or adenylate cyclase (SQ22536). The effect of IVA on ACh-induced contraction was also measured in isolated muscle cells in the presence or absence of SQ22536 or protein kinase A (PKA) inhibitor (H-89). Direct activation of PKA was measured in isolated muscle cells.

RESULTS

In colonic segments, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion; the IVA response was not affected by TTx or L-NNA but inhibited by SQ22536. Similarly, in isolated colonic muscle cells, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion and the effect blocked by SQ22536 and H-89. IVA also increased PKA activity in isolated smooth muscle cells.

CONCLUSIONS

The branched-chain fatty acid IVA acts directly on colonic smooth muscle and causes muscle relaxation via the PKA pathway.

Effect of probiotic and synbiotic supplementation on inflammatory markers in health and disease status: A systematic review and meta-analysis of clinical trials

The current systematic review and meta-analysis investigated the effect of probiotic/synbiotic on a wide range of inflammatory and anti-inflammatory markers in healthy and various disease conditions. PubMed, SCOPUS and Web of Science databases were searched. All clinical trials which investigated the effect of oral administration of probiotic or synbiotic on inflammatory markers (C-reactive protein (CRP), interleukin (IL) 1β, IL-4, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor (TNF) α, interferon (IFN) γ and transforming growth factor (TGF) β) for more than one week with concurrent control groups were included. One-hundred sixty seven publications was analysed. Results were as follows: CRP decreased in healthy, metabolic disorders, inflammatory bowel disease (IBD), arthritis and critically ill condition but not in renal failure. IL-1B: no change in healthy subjects and arthritis. TNF-α: decreased in healthy, fatty liver, IBD and hepatic cirrhosis, no change in diabetes, metabolic syndrome (MS) + PCOS (polycystic ovary syndrome) and arthritis. IL-6: no change in healthy, metabolic disorders and arthritis, increased in cirrhosis and renal failure, decreased in PCOS + MS. IL-10: no change in healthy, IBD and metabolic disorders, increased in arthritis. IL-4, IL-8, IL-12, IFN-g and TGF-b: no change in healthy subjects. In conclusion, probiotic/synbiotic decreased some of the inflammatory markers. The intervention was most effective in CRP and TNF-α reduction in healthy or disease state. Moreover, the intervention decreased inflammation most effectively in the following disease conditions, respectively: IBD, arthritis, fatty liver. PROSPERO REGISTRATION NUMBER: CRD42018088688.

Lactobacillus fermentum and Lactobacillus plantarum increased gut microbiota diversity and functionality, and mitigated Enterobacteriaceae, in a mouse model

Probiotics should bring 'balance' to the intestinal microbiota by stimulating beneficial bacteria, whilst mitigating adverse ones. Balance can also be interpreted as high alpha-diversity. Contrary, Escherichia coli is often regarded as an adverse component of the resident intestinal microbiota. The aim of the present study was to implement a mouse model for in vivo screening of Lactobacillus-strains for ability to increase gut-microbiota diversity and to mitigate E. coli. Mice were divided into six groups, two dietary control-groups and four groups administered strains of Lactobacillus fermentum and/or Lactobacillus plantarum. All animals were pre-treated with antibiotics, and E. coli in order to equalise the microbiota from the start. After 7 weeks of Lactobacillus administration, the animals were sacrificed: DNA was extracted from caecum tissue, and the microbiota composition was analysed with terminal restriction fragment length polymorphism (T-RFLP) and 16S rRNA gene sequencing. The diversity of the caecal microbiota decreased when the dietary carbohydrate source was limited to corn starch. Conversely, the diversity was restored by Lactobacillus-supplements. The tested combinations of two Lactobacillus strains exerted different influences, not only on the taxonomic level, but also on the inferred microbiome functions. The mixture of L. fermentum GOS47 and L. fermentum GOS1 showed potential for anti-inflammatory activity and short chain fatty acid production. On the other hand, co-administration of L. fermentum GOS57 and L. plantarum GOS42 significantly decreased the viable count of Enterobacteriaceae. These results warrant further investigation of the tested strains as candidates for probiotics. Furthermore, the findings demonstrated that the current experimental animal model is suitable for in vivo studies of the effect of bacterial supplements on the gut-microbiota.

Endocrine organs of cardiovascular diseases: Gut microbiota

Gut microbiota (GM) is a collection of bacteria, fungi, archaea, viruses and protozoa, etc. They inhabit human intestines and play an essential role in human health and disease. Close information exchange between the intestinal microbes and the host performs a vital role in digestion, immune defence, nervous system regulation, especially metabolism, maintaining a delicate balance between itself and the human host. Studies have shown that the composition of GM and its metabolites are firmly related to the occurrence of various diseases. More and more researchers have demonstrated that the intestinal microbiota is a virtual 'organ' with endocrine function and the bioactive metabolites produced by it can affect the physiological role of the host. With deepening researches in recent years, clinical data indicated that the GM has a significant effect on the occurrence and development of cardiovascular diseases (CVD). This article systematically elaborated the relationship between metabolites of GM and its effects, the relationship between intestinal dysbacteriosis and cardiovascular risk factors, coronary heart disease, myocardial infarction, heart failure and hypertension and the possible pathogenic mechanisms. Regulating the GM is supposed to be a potential new therapeutic target for CVD.

Lactobacillus plantarum ZDY04 exhibits a strain-specific property of lowering TMAO via the modulation of gut microbiota in mice

Trimethylamine N-oxide (TMAO), which is oxidized from trimethylamine (TMA) by hepatic flavin-containing monooxygenases (FMOs), promotes the development of atherosclerosis and is a new target for the prevention and treatment of cardiovascular disease from the perspective of intestinal flora. TMA is transformed by intestinal flora from TMA-containing nutrients, such as choline. Some small molecular agents lower serum TMAO and/or cecal TMA levels. However, probiotics that can effectively reduce serum TMAO levels are currently lacking. In this work, five potentially probiotic strains were administered to mice supplemented with 1.3% choline. Only Lactobacillus plantarum ZDY04 significantly reduced serum TMAO and cecal TMA levels by modulating the relative abundance of the families Lachnospiraceae, Erysipelotrichaceae and Bacteroidaceae and the genus Mucispirillum in mice and not by influencing the expression levels of hepatic FMO3 and metabolizing choline, TMA, and TMAO. In addition, L. plantarum ZDY04 can significantly inhibit the development of TMAO-induced atherosclerosis in ApoE-/- 1.3% choline-fed mice as compared with the untreated PBS group. In conclusion, the use of L. plantarum ZDY04 may be an alternative approach to reduce serum TMAO levels and TMAO-induced atherosclerosis in mice.

Dietary Composition and Cardiovascular Risk: A Mediator or a Bystander?

The role of nutrition in the pathogenesis of cardiovascular disease has long been debated. The established notion of the deleterious effects of fat is recently under question, with numerous studies demonstrating the benefits of low-carbohydrate, high-fat diets in terms of obesity, diabetes, dyslipidemia, and metabolic derangement. Monounsaturated and polyunsaturated fatty acids, especially n-3 PUFAs (polyunsaturated fatty acids), are the types of fat that favor metabolic markers and are key components of the Mediterranean Diet, which is considered an ideal dietary pattern with great cardioprotective effects. Except for macronutrients, however, micronutrients like polyphenols, carotenoids, and vitamins act on molecular pathways that affect oxidative stress, endothelial function, and lipid and glucose homeostasis. In relation to these metabolic markers, the human gut microbiome is constantly revealed, with its composition being altered by even small dietary changes and different microbial populations being associated with adverse cardiovascular outcomes, thus becoming the target for potential new treatment interventions. This review aims to present the most recent data concerning different dietary patterns at both the macro- and micronutrient level and their association with atherosclerosis, obesity, and other risk factors for cardiovascular disease.

Use of Gas Chromatography to Quantify Short Chain Fatty Acids in the Serum, Colonic Luminal Content and Feces of mice

Short-Chain Fatty Acids (SCFAs) are a product of the fermentation of resistant starches and dietary fibers by the gut microbiota. The most important SCFA are acetate (C2), propionate (C3) and butyrate (C4). These metabolites are formed and absorbed in the colon and then transported through the hepatic vein to the liver. SCFAs are more concentrated in the intestinal lumen than in the serum. Butyrate is largely consumed in the gut epithelium, propionate in the liver and acetate in the periphery. SCFAs act on many cells including components of the immune system and epithelial cells by two main mechanisms: activation of G-protein coupled receptors (GPCRs) and inhibition of histone deacetylase. Considering the association between changes in SCFA concentrations and the development of diseases, methods to quantify these acids in different biological samples are important. In this study, we describe a protocol using gas chromatography to quantify SCFAs in the serum, feces and colonic luminal content. Separation of compounds was performed using a DB-23 column (60 m x 0.25 mm internal diameter [i.d.]) coated with a 0.15 µm thick layer of 80.2% 1-methylnaphatalene. This method has a good linear range (15-10,000 µg/ml). The precision (relative standard deviation [RSD]) is less than 15.0% and the accuracy (error relative [ER]) is within ± 15.0%. The extraction efficiency was higher than 97.0%. Therefore, this is cost effective and reproducible method for SCFA measurement in feces and serum.

Diagnostics and therapeutic implications of gut microbiota alterations in cardiometabolic diseases

Alterations in gut microbiota composition and its metabolic activity are emerging as one of the most powerful determinants of cardiovascular disease. Although our knowledge of the precise molecular mechanisms by which gut microbiota influences cardiometabolic homeostasis is still limited, a growing body of knowledge has recently been uncovered about the potential modulation of microbiome for cardiovascular diagnostic and therapeutic aspects. The multitude of interactions between the microorganisms inhabiting the digestive tract and the host has been recognized crucial in the development and progression of atherosclerosis, obesity, diabetes and hypertension. Here, we summarize the role of gut microbiota in host physiology as well as in the pathophysiology of the most common cardio-metabolic disorders, discussing the potential therapeutic opportunities offered by interventions aimed at modifying microbiome composition and activity.

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.

Gut Microbiota in Cardiovascular Health and Disease

Significant interest in recent years has focused on gut microbiota-host interaction because accumulating evidence has revealed that intestinal microbiota play an important role in human health and disease, including cardiovascular diseases. Changes in the composition of gut microbiota associated with disease, referred to as dysbiosis, have been linked to pathologies such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus. In addition to alterations in gut microbiota composition, the metabolic potential of gut microbiota has been identified as a contributing factor in the development of diseases. Recent studies revealed that gut microbiota can elicit a variety of effects on the host. Indeed, the gut microbiome functions like an endocrine organ, generating bioactive metabolites, that can impact host physiology. Microbiota interact with the host through many pathways, including the trimethylamine/trimethylamine N-oxide pathway, short-chain fatty acids pathway, and primary and secondary bile acids pathways. In addition to these metabolism-dependent pathways, metabolism-independent processes are suggested to also potentially contribute to cardiovascular disease pathogenesis. For example, heart failure-associated splanchnic circulation congestion, bowel wall edema, and impaired intestinal barrier function are thought to result in bacterial translocation, the presence of bacterial products in the systemic circulation and heightened inflammatory state. These are thought to also contribute to further progression of heart failure and atherosclerosis. The purpose of the current review is to highlight the complex interplay between microbiota, their metabolites, and the development and progression of cardiovascular diseases. We will also discuss the roles of gut microbiota in normal physiology and the potential of modulating intestinal microbial inhabitants as novel therapeutic targets.