Dietary metabolism, the gut microbiome, and heart failure

Gut microbiota: A new therapeutic target for diabetic cardiomyopathy

Diabetic cardiomyopathy seriously affects quality of life and even threatens life safety of patients. The pathogenesis of diabetic cardiomyopathy is complex and multifactorial, and it is widely accepted that its mechanisms include oxidative stress, inflammation, insulin resistance, apoptosis, and autophagy. Some studies have shown that gut microbiota plays an important role in cardiovascular diseases. Gut microbiota and its metabolites can affect the development of diabetic cardiomyopathy by regulating oxidative stress, inflammation, insulin resistance, apoptosis, and autophagy. Here, the mechanisms of gut microbiota and its metabolites resulting in diabetic cardiomyopathy are reviewed. Gut microbiota may be a new therapeutic target for diabetic cardiomyopathy.

Mechanisms shared between cancer, heart failure, and targeted anti-cancer therapies

Heart failure (HF) and cancer are the leading causes of death worldwide and accumulating evidence demonstrates that HF and cancer affect one another in a bidirectional way. Patients with HF are at increased risk for developing cancer, and HF is associated with accelerated tumour growth. The presence of malignancy may induce systemic metabolic, inflammatory, and microbial alterations resulting in impaired cardiac function. In addition to pathophysiologic mechanisms that are shared between cancer and HF, overlaps also exist between pathways required for normal cardiac physiology and for tumour growth. Therefore, these overlaps may also explain the increased risk for cardiotoxicity and HF as a result of targeted anti-cancer therapies. This review provides an overview of mechanisms involved in the bidirectional connection between HF and cancer, specifically focusing upon current 'hot-topics' in these shared mechanisms. It subsequently describes targeted anti-cancer therapies with cardiotoxic potential as a result of overlap between their anti-cancer targets and pathways required for normal cardiac function.

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.

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

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

Analyzing the Complicated Connection Between Intestinal Microbiota and Cardiovascular Diseases

Relentless human curiosity to understand the basis of every aspect of medical science has led humanity to unlock the deepest secrets about the physiology of human existence and, in the process, has reached milestones that a century ago could only be imagined. Recent ground-breaking breakthroughs have helped scientists and physicians all over the world to update the scientific basis of diseases and hence further improve treatment outcomes. According to recent studies, scientists have found a link between intestinal flora and the pathogenesis of diseases, including cardiovascular diseases. Any change in the typical habitat of gut microbiota has been shown to result in the culmination of various metabolic and cardiac diseases. Therefore, gut microbiota can be credited for influencing the course of the development of a disease. Any change in the composition and function of bacterial species living in the gut can result in both beneficial and harmful effects on the body. Gut microbiota achieves this role by numerous mechanisms. Generations of various metabolites like TMAO (trimethylamine N-oxide), increased receptibility of various bacterial antigens, and disruption of the enzyme action in various metabolic pathways like the bile acids pathway may result in the development of metabolic as well as cardiovascular diseases. Even if they may not be the only etiological factor in the pathogenesis of a disease, they may very well serve as a contributing factor in worsening the outcome of the condition. Studies have shown that they actively play a role in the progression of cardiovascular diseases like atherosclerotic plaque formation and rising blood pressure. The focus of this review article is to establish a relation between various cardiovascular diseases and gut microbiota. This could prove beneficial for clinicians, health care providers, and scientists to develop novel therapeutic algorithms while treating cardiac patients.

Targeting Gut Microbiota as a Novel Strategy for Prevention and Treatment of Hypertension, Atrial Fibrillation and Heart Failure: Current Knowledge and Future Perspectives

Cardiovascular diseases (CVDs) remain the major public health concern worldwide. Over the last two decades, a considerable amount of literature has been published on gut microbiota (GMB) composition and its metabolites, involved in the pathophysiology of CVDs, including arterial hypertension, atrial fibrillation, and congestive heart failure. Although many types of medicines are available to treat CVD, new therapeutic tools are needed to improve clinical outcomes. A challenge that often arises in the researchers’ community is how to manipulate the GMB to manage cardiovascular risk factors. Therapeutic strategies designed to manipulate GMB composition and/or its metabolites include dietary approaches, prebiotics/probiotics supplementation, and fecal microbiota transplantation (FMT). In this review, we have focused on three main cardiovascular pathologies (arterial hypertension, atrial fibrillation and heart failure) due to their shared common pathophysiological pathways and structural changes in myocardium, such as inflammation, hypertrophy, fibrosis, and myocardial remodeling. The main aims of the review are: (1) to summarize current knowledge on the key pathophysiologic links between GMB and CVDs, and (2) discuss the results of the studies on GMB modulation for the prevention and treatment of selected CVDs.

Physiopathological mechanisms involved in the development of hypertension associated with gut dysbiosis and the effect of nutritional/pharmacological interventions

The gut microbiota dysbiosis represents a triggering factor for cardiovascular diseases, including hypertension. In addition to the harmful impact caused by hypertension on different target organs, gut dysbiosis is capable of causing direct damage to critical organs such as the brain, heart, blood vessels, and kidneys. In this sense, it should be noted that pharmacological and nutritional interventions may influence gut microbiota composition, either inducing or preventing the development of hypertension. Some of the most important nutritional interventions at this level are represented by pro-, pre-, post- and/or syn-biotics, as well as polysaccharides, polyunsaturated fatty acids ω-3, polyphenols and fiber contained in different foods. Meanwhile, certain natural and synthetic active pharmaceutical ingredients, including antibiotics, antihypertensive and immunosuppressive drugs, vegetable extracts and vitamins, may also have a key role in the modulation of both gut microbiota and cardiovascular health. Additionally, gut microbiota may influence drugs and food-derived bioactive compounds metabolism, positively or negatively affecting their biological behavior facing established hypertension. The understanding of the complex interactions between gut microbiome and drug/food response results of great importance to developing improved pharmacological therapies for hypertension prevention and treatment. The purpose of this review is to critically outline the most relevant and recent findings on cardiovascular, renal and brain physiopathological mechanisms involved in the development of hypertension associated with changes in gut microbiota, besides the nutritional and pharmacological interventions potentially valuable for the prevention and treatment of this prevalent pathology. Finally, harmful food/drug interventions on gut microbiota are also described.

Emerging trends and focus for the link between the gastrointestinal microbiome and kidney disease

The clinical value of the relationship between gastrointestinal microbiome imbalance and its corresponding interventions with kidney disease is emerging. This study describes the hotspots and evolution of gastrointestinal microbiome and kidney disease research over the past three decades by scientific collaboration networks and finally predicts future trends in the field through bibliometric analysis and visualization studies. CiteSpace was used to explore the original articles from January 1990 to August 2021 to visualize the knowledge network of journals, countries, institutions, authors, references, and keywords in this field. Publications were extracted from Web of Science Core Collection database using the terms “gastrointestinal microbiome” and “kidney disease” (and their synonyms in MeSH). A total of 2145 publications with 93880 references in 102 journals were included in the analyses. The number of studies combining gastrointestinal microbiomes with kidney diseases has increased significantly over the past two decades. The United States is the leading country in the number of documents, and the leading institution is the Cleveland Clinic. The most landmark articles in the field are on chronic renal failure, L-Carnitin, and cardiovascular disease. The pathogenesis of uremia toxin is an emerging trend in gastrointestinal microbiomes and kidney diseases. In addition, probiotic or synbiotic supplements have strong clinical value in adjusting abnormal intestinal symbiotic environments. This study demonstrates a growing understanding of the interaction between gut microbiota and kidney disease over time. Using microbial supplements to improve the living conditions of kidney disease patients is a promising and hot research focus. Based on publications extracted from the database, this study may provide clinicians and researchers with valuable information to identify potential collaborators and partner institutions and better predict their dynamic progression.

Synbiotics and Gut Microbiota: New Perspectives in the Treatment of Type 2 Diabetes Mellitus

The number of people with type 2 diabetes mellitus (T2DM) has increased sharply over the past decades. Apart from genetic predisposition, which may cause some of the diagnosed cases, an unhealthy diet and lifestyle are incentive triggers of this global epidemic. Consumption of probiotics and prebiotics to gain health benefits has become increasingly accepted by the public in recent years, and their critical roles in alleviating T2DM symptoms are confirmed by accumulating studies. Microbiome research reveals gut colonization by probiotics and their impacts on the host, while oral intake of prebiotics may stimulate existing metabolisms in the colon. The use of synbiotics (a combination of prebiotics and probiotics) can thus show a synergistic effect on T2DM through modulating the gastrointestinal microenvironment. This review summarizes the research progress in the treatment of T2DM from the perspective of synbiotics and gut microbiota and provides a class of synbiotics which are composed of lactulose, arabinose, and Lactobacillus plantarum, and can effectively adjust the blood glucose, blood lipid, and body weight of T2DM patients to ideal levels.

Akkermansia muciniphila prevents cold-related atrial fibrillation in rats by modulation of TMAO induced cardiac pyroptosis

Background

Cold exposure is one of the most important risk factors for atrial fibrillation (AF), and closely related to the poor prognosis of AF patients. However, the mechanisms underlying cold-related AF are poorly understood.

Methods

Various techniques including 16S rRNA gene sequencing, fecal microbiota transplantation, and electrophysiological examination were used to determine whether gut microbiota dysbiosis promotes cold-related AF. Metabonomics were performed to investigate changes in fecal trimethylamine (TMA) and plasma trimethylamine N-oxide (TMAO) during cold exposure. The detailed mechanism underlying cold-related AF were examined in vitro. Transgenic mice were constructed to explore the role of pyroptosis in cold-related AF. The human cohort was used to evaluate the correlation between A. muciniphila and cold-related AF.

Findings

We found that cold exposure caused elevated susceptibility to AF and reduced abundance of Akkermansia muciniphila (A. muciniphila) in rats. Intriguingly, oral supplementation of A. muciniphila ameliorated the pro-AF property induced by cold exposure. Mechanistically, cold exposure disrupted the A. muciniphila, by which elevated the level of trimethylamine N-oxide (TMAO) through modulation of the microbial enzymes involved in trimethylamine (TMA) synthesis. Correspondingly, progressively increased plasma TMAO levels were validated in human subjects during cold weather. Raised TMAO enhanced the infiltration of M1 macrophages in atria and increased the expression of Casp1-p20 and cleaved-GSDMD, ultimately causing atrial structural remodeling. Furthermore, the mice with conditional deletion of caspase1 exhibited resistance to cold-related AF. More importantly, a cross-sectional clinical study revealed that the reduction of A. muciniphila abundance was an independent risk factor for cold-related AF in human subjects.

Interpretation

Our findings revealed a novel causal role of aberrant gut microbiota and metabolites in pathogenesis of cold-related AF, which raises the possibility of selectively targeting microbiota and microbial metabolites as a potential therapeutic strategy for cold-related AF.

Funding

This work was supported by grants from the State Key Program of National Natural Science Foundation of China (No.81830012), and National Natural Science Foundation of China (No.82070336, No.81974024), Youth Program of the National Natural Science Foundation of China (No.81900374, No.81900302), and Excellent Young Medical Talents supporting project in the First Affiliated Hospital of Harbin Medical University (No. HYD2020YQ0001).

Circulating 1,3-Beta-D-Glucan is Associated with Lung Function, Respiratory Symptoms, and Mediators of Matrix Degradation in Chronic Obstructive Pulmonary Disease

Introduction

Factors beyond cigarette smoke likely contribute to chronic obstructive pulmonary disease (COPD) pathogenesis. Prior studies demonstrate fungal colonization of the respiratory tract and increased epithelial barrier permeability in COPD. We sought to determine whether 1,3-beta-d-glucan (BDG), a polysaccharide component of the fungal cell wall, is detectable in the plasma of individuals with COPD and associates with clinical outcomes and matrix degradation proteins.

Methods

BDG was measured in the plasma of current and former smokers with COPD. High BDG was defined as a value greater than the 95^th percentile of BDG in smokers without airflow obstruction. Pulmonary function, emphysema, and symptoms were compared between COPD participants with high versus low BDG. The relationship between plasma BDG, matrix metalloproteinases (MMP) 1, 7, and 9, and tissue inhibitor of matrix metalloproteinases (TIMP) 1, 2, and 4 was assessed adjusting for age, sex, and smoking status.

Results

COPD participants with high BDG plasma levels (19.8%) had lower forced expiratory volume in 1 second to forced vital capacity ratios (median 31.9 versus 39.3, p=0.025), higher St George's Respiratory Questionnaire symptom scores (median 63.6 versus 57.4, p=0.016), and greater prevalence of sputum production (69.4% versus 52.0%) and exacerbations (69.4% versus 48%) compared to COPD participants with low BDG. BDG levels directly correlated with MMP1 (r=0.27, p<0.001) and TIMP1 (r=0.16, p=0.022) in unadjusted and adjusted analyses.

Conclusions

Elevated plasma BDG levels correlate with worse lung function, greater respiratory morbidity, and circulating markers of matrix degradation in COPD. These findings suggest that targeting dysbiosis or enhancing epithelial barrier integrity may have disease-modifying effects in COPD.

Gut Microbially Produced Indole-3-Propionic Acid Inhibits Atherosclerosis by Promoting Reverse Cholesterol Transport and Its Deficiency Is Causally Related to Atherosclerotic Cardiovascular Disease

BACKGROUND

Accumulating evidence has shown that disorders in the gut microbiota and derived metabolites affect the development of atherosclerotic cardiovascular disease (ASCVD). However, which and how specific gut microbial metabolites contribute to the progression of atherosclerosis and the clinical relevance of their alterations remain unclear.

METHODS

We performed integrated microbiome-metabolome analysis of 30 patients with coronary artery disease (CAD) and 30 age- and sex-matched healthy controls to identify CAD-associated microbial metabolites, which were then assessed in an independent population of patients with ASCVD and controls (n=256). We further investigate the effect of CAD-associated microbial metabolites on atherosclerosis and the mechanisms of the action.

RESULTS

Indole-3-propionic acid (IPA), a solely microbially derived tryptophan metabolite, was the most downregulated metabolite in patients with CAD. Circulating IPA was then shown in an independent population to be associated with risk of prevalent ASCVD and correlated with the ASCVD severity. Dietary IPA supplementation alleviates atherosclerotic plaque development in ApoE^-/- mice. In murine- and human-derived macrophages, administration of IPA promoted cholesterol efflux from macrophages to ApoA-I through an undescribed miR-142-5p/ABCA1 (ATP-binding cassette transporter A1) signaling pathway. Further in vivo studies demonstrated that IPA facilitates macrophage reverse cholesterol transport, correlating with the regulation of miR-142-5p/ABCA1 pathway, whereas reduced IPA production contributed to the aberrant overexpression of miR-142-5p in macrophages and accelerated the progression of atherosclerosis. Moreover, the miR-142-5p/ABCA1/reverse cholesterol transport axis in macrophages were dysregulated in patients with CAD, and correlated with the changes in circulating IPA levels.

CONCLUSIONS

Our study identify a previously unknown link between specific gut microbiota-derived tryptophan metabolite and ASCVD. The microbial metabolite IPA/miR-142-5p/ABCA1 pathway may represent a promising therapeutic target for ASCVD.

Integrating 16S rRNA gene sequencing and metabolomics to evaluate the association between gut microbiota and serum metabolites in patients with myositis

AIMS

Gut microbiota and metabolites have a profound impact on the maintenance of body health. In this study, we assessed the association between gut microbiota and serum metabolite changes in myositis using 16S rRNA gene sequencing and metabolomics to provide new ideas for screening and treating myositis.

METHODS AND RESULTS

Blood and fecal samples were collected from twenty myositis patients and twenty healthy control subjects. Then, 16S rRNA gene sequencing, enzyme-linked immunosorbent assays, and untargeted metabolomics study were performed to evaluate the relationship between gut microbiota and serum metabolites in patients with myositis. Compared to healthy control subjects, the blood samples from the patients with myositis had elevated levels of interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α), and malondialdehyde (MDA), and decreased superoxide dismutase (SOD) levels. The increase in Bacteroidota (including Bacteroides and Parabacteroides, but not Prevotella) and the decrease in Firmicutes in the patients were accompanied by functional changes in amino acid and lipid metabolism. The gut microbiota (Bacteroides and Parabacteroides) were negatively correlated with the differential serum metabolites (glutamate and taurine). The differential serum metabolites (glutamate, pyrrolidonecarboxylic acid, and taurine) were also correlated with inflammatory factors (IL-4 and TNF-α) and oxidative stress indexes (MDA and SOD).

CONCLUSION

Dysbiosis of gut microbiota in patients with myositis was accompanied by changes in inflammatory factors, oxidative stress indexes, and small molecule metabolites in serum.

SIGNIFICANCE AND IMPACT OF STUDY

Blood and fecal biomarkers could be used for screening myositis.

Lacticaseibacillus rhamnosus Fmb14 prevents purine induced hyperuricemia and alleviate renal fibrosis through gut-kidney axis

Hyperuricemia is a critical threat to human health, and conventional medical treatment only aims to treat acute gouty arthritis. Purine diet-mediated chronic hyperuricemia and related syndromes are neglected in clinical therapeutics. In this study, the prevention ability of Lacticaseibacillus rhamnosus Fmb14, screened from Chinese yogurt, was evaluated in chronic purine-induced hyperuricemia (CPH) mice. After 12 weeks of Fmb14 administration, serum uric acid (SUA) in CPH mice decreased by 36.8 %, from 179.1 to 113.2 µmol/L, and the mortality rate decreased from 30 % to 10 %. The prevention role of Fmb14 in CPH was further investigated, and the reduction of uric acid by Fmb14 was attributed to the reduction of XOD (xanthine oxidase) in the liver and URAT1 in the kidney, as well the promotion of ABCG2 in the colon. Fmb14 administration Increased ZO-1 and Occludin expression in the colon and decreased fibrosis degree in the kidney indicated that Fmb14 administration had preventive effects through the gut-kidney axis in CPH. In specific, Fmb14 administration upregulated the diversity of gut microbiota, increased short-chain fatty acids (SCFA) by 35 % in colon materials and alleviated the inflammatory response by reducing biomarkers levels of IL-1β, IL-18 and TNF-α at 11.6 %, 21.7 % and 26.5 % in serum, compared to CPH group, respectively. Additionally, 16 S rRNA sequencing showed 31.5 % upregulation of Prevotella, 20.5 % and 21.6 % downregulation of Ruminococcus and Suterella at the genus level, which may be a new gut microbial marker in hyperuricemia. In conclusion, Fmb14 ameliorated CPH through the gut-kidney axis, suggesting a new strategy to prevent hyperuricemia.

Understanding How Heart Metabolic Derangement Shows Differential Stage Specificity for Heart Failure with Preserved and Reduced Ejection Fraction

Heart failure (HF) is a clinical condition defined by structural and functional abnormalities in the heart that gradually result in reduced cardiac output (HFrEF) and/or increased cardiac pressures at rest and under stress (HFpEF). The presence of asymptomatic individuals hampers HF identification, resulting in delays in recognizing patients until heart dysfunction is manifested, thus increasing the chance of poor prognosis. Given the recent advances in metabolomics, in this review we dissect the main alterations occurring in the metabolic pathways behind the decrease in cardiac function caused by HF. Indeed, relevant preclinical and clinical research has been conducted on the metabolite connections and differences between HFpEF and HFrEF. Despite these promising results, it is crucial to note that, in addition to identifying single markers and reliable threshold levels within the healthy population, the introduction of composite panels would strongly help in the identification of those individuals with an increased HF risk. That said, additional research in the field is required to overcome the current drawbacks and shed light on the pathophysiological changes that lead to HF. Finally, greater collaborative data sharing, as well as standardization of procedures and approaches, would enhance this research field to fulfil its potential.

Effects of iodoacetic acid drinking water disinfection byproduct on the gut microbiota and its metabolism in rats

Iodoacetic acid (IAA) is an unregulated disinfection byproduct in drinking water and has been shown to exert cytotoxicity, genotoxicity, tumorigenicity, and reproductive and developmental toxicity. However, the effects of IAA on gut microbiota and its metabolism are still unknown, especially the association between gut microbiota and the metabolism and toxicity of IAA. In this study, female and male Sprague-Dawley rats were exposed to IAA at 0 and 16 mg/kg bw/day daily for 8 weeks by oral gavage. Results of 16S rRNA gene sequencing showed that IAA could alter the diversity, relative abundance and function of gut microbiota in female and male rats. IAA also increased the abundance of genes related to steroid hormone biosynthesis in the gut microbiota of male rats. Moreover, metabolomics profiling revealed that IAA could significantly disturb 6 and 13 metabolites in the feces of female and male rats, respectively. In female rats, the level of androstanediol increased in the IAA treatment group. These results were consistent with our previous findings, where IAA was identified as an androgen disruptor. Additionally, the perturbed gut microbiota and altered metabolites were correlated with each other. The results of this study indicated that IAA could disturb gut microbiota and its metabolism. These changes in gut microbiota and its metabolism were associated with the reproductive and developmental toxicity of IAA.

Gut microbiota in sarcopenia and heart failure

Sarcopenia is common in aging and in patients with heart failure (HF) who may experience worse outcomes. Patients with muscle wasting are more likely to experience falls and can have serious complications when undergoing cardiac procedures. While intensive nutritional support and exercise rehabilitation can help reverse some of these changes, they are often under-prescribed in a timely manner, and we have limited insights into who would benefit. Mechanistic links between gut microbial metabolites (GMM) have been identified and may contribute to adverse clinical outcomes in patients with cardio-renal diseases and aging. This review will examine the emerging evidence for the influence of the gut microbiome-derived metabolites and notable signaling pathways involved in both sarcopenia and HF, especially those linked to dietary intake and mitochondrial metabolism. This provides a unique opportunity to gain mechanistic and clinical insights into developing novel therapeutic strategies that target these GMM pathways or through tailored nutritional modulation to prevent progressive muscle wasting in elderly patients with heart failure.

Short-term acute constipation and not short-term acute diarrhea altered cardiovascular variables in male Wistar rats

Gastrointestinal dysmotility is a substantial public health challenge globally. Based on previous findings in developed countries, it has been observed that there is an association between diarrhea, constipation, and some cardiovascular variables. This study investigated the effects of experimentally-induced short-term acute constipation and short-term acute diarrhea on certain cardiovascular variables in rats. Thirty (30) male Wistar rats (150 -180 g) were divided into three groups; Control, Diarrhoea, and Constipation. The experiment was carried out in 2 phases, the period after induction and the recovery period, and 5 animals per group were used for each phase. The control group received an equivalent amount of distilled water while Diarrhoea and the Constipation group were induced by oral administration of 2ml Castor oil and administration of Loperamide (3mg/kg, b.d, orally x 3 days), respectively. Cardiovascular variables were assessed using the Edan Scientific® Electrocardiography and  Heart Rate Variability machine. Recovery was allowed for 4 days after the onset of the procedure and cardiovascular parameters were reassessed. Post-induction Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP) and Heart Rate (HR) significantly increased in constipated rats (153.2 ± 2.9 mmHg; 109.0 ± 3.7 mmHg;     123.7 ± 3.2 mmHg; 123.4±5.6 bpm) when compared with the control values (95.5±4.8 mmHg; 61.2 ± 3.5 mmHg; 72.6 ± 3.6 mmHg; 72.3 ± 5.2 bpm), respectively. The recovery SBP, DBP, MAP, and Heart Rate in the constipated group remained significantly higher compared to the control. Diarrhea had no significant effect on the parameters determined in both post-induction and recovery phases. The electrical activities did not change in both experimental groups compared to the control. This study revealed increased SBP, DBP, MAP, and HR in short-term acute constipated rats but not so with short-term acute experimental diarrhea.

Type 2 diabetes mellitus-associated cognitive dysfunction: Advances in potential mechanisms and therapies

Type 2 diabetes (T2D) and its target organ injuries cause distressing impacts on personal health and put an enormous burden on the healthcare system, and increasing attention has been paid to T2D-associated cognitive dysfunction (TDACD). TDACD is characterized by cognitive dysfunction, delayed executive ability, and impeded information-processing speed. Brain imaging data suggest that extensive brain regions are affected in patients with T2D. Based on current findings, a wide spectrum of non-specific neurodegenerative mechanisms that partially overlap with the mechanisms of neurodegenerative diseases is hypothesized to be associated with TDACD. However, it remains unclear whether TDACD is a consequence of T2D or a complication that co-occurs with T2D. Theoretically, anti-diabetes methods are promising neuromodulatory approaches to reduce brain injury in patients with T2D. In this review, we summarize potential mechanisms underlying TDACD and promising neurotropic effects of anti-diabetes methods and some neuroprotective natural compounds. Constructing screening or diagnostic tools and developing targeted treatment and preventive strategies would be expected to reduce the burden of TDACD.

Ongoing Clinical Trials in Aging-Related Tissue Fibrosis and New Findings Related to AhR Pathways

Fibrosis is a pathological manifestation of wound healing that replaces dead/damaged tissue with collagen-rich scar tissue to maintain homeostasis, and complications from fibrosis contribute to nearly half of all deaths in the industrialized world. Ageing is closely associated with a progressive decline in organ function, and the prevalence of tissue fibrosis dramatically increases with age. Despite the heavy clinical and economic burden of organ fibrosis as the population ages, to date, there is a paucity of therapeutic strategies that are specifically designed to slow fibrosis. Aryl hydrocarbon receptor (AhR) is an environment-sensing transcription factor that exacerbates aging phenotypes in different tissues that has been brought back into the spotlight again with economic development since AhR could interact with persistent organic pollutants derived from incomplete waste combustion. In addition, gut microbiota dysbiosis plays a pivotal role in the pathogenesis of numerous diseases, and microbiota-associated tryptophan metabolites are dedicated contributors to fibrogenesis by acting as AhR ligands. Therefore, a better understanding of the effects of tryptophan metabolites on fibrosis modulation through AhR may facilitate the exploitation of new therapeutic avenues for patients with organ fibrosis. In this review, we primarily focus on how tryptophan-derived metabolites are involved in renal fibrosis, idiopathic pulmonary fibrosis, hepatic fibrosis and cardiac fibrosis. Moreover, a series of ongoing clinical trials are highlighted.

Intestinal Microflora Changes in Patients with Mild Alzheimer's Disease in a Chinese Cohort

BACKGROUND

Understanding the relationship between Alzheimer's disease (AD) and intestinal flora is still a major scientific topic that continues to advance.

OBJECTIVE

To determine characterized changes in the intestinal microbe community of patients with mild AD.

METHODS

Comparison of the 16S ribosomal RNA (rRNA) high-throughput sequencing data was obtained from the Illumina MiSeq platform of fecal microorganisms of the patients and healthy controls (HC) which were selected from cohabiting caregivers of AD patients to exclude environmental and dietary factors.

RESULTS

We found that the abundance of several bacteria taxa in AD patients was different from that in HC at the genus level, such as Anaerostipes, Mitsuokella, Prevotella, Bosea, Fusobacterium, Anaerotruncus, Clostridium, and Coprobacillus. Interestingly, the abundance of Akkermansia, an emerging probiotic, increased significantly in the AD group compared with that in the HC group. Meanwhile, the quantity of traditional probiotic Bifidobacteria of the AD group also rose.

CONCLUSION

These alterations in fecal microbiome of the AD group indicate that patients with mild AD have unique gut microbial characteristics. These specific AD-associated intestinal microbes could serve as novel potential targets for early intervention of AD.

Phenylacetylglutamine as a risk factor and prognostic indicator of heart failure

AIMS

To explore the associations between serum phenylacetylglutamine (PAGln) and chronic heart failure (HF).

METHODS AND RESULTS

Totally 956 subjects were enrolled consecutively from the Department of Cardiovascular Medicine, Ruijin Hospital. Baseline data were obtained from all participants, and 471 stable chronic HF subjects were followed up. Serum PAGln was analysed by liquid chromatography-tandem mass spectrometry. The association between PAGln and basic renal indicators was assessed by simple correlation analysis. Logistic regression analysis was conducted to measure the association between PAGln and HF risk. Event-free survival was determined by Kaplan-Meier curves, and differences in survival were assessed using log-rank tests. Cox proportional hazards analysis was used to assess the prognostic value of PAGln in HF. Serum PAGln levels were increased in patients with chronic HF (3.322 ± 8.220 μM vs. 1.249 ± 1.168 μM, P < 0.001) and were associated with HF after full adjustment [odds ratio (OR), 1.507; 95% confidence interval (CI): 1.213-1.873; P < 0.001]. PAGln levels were correlated with the levels of basic renal indicators. High PAGln levels indicated a high risk of renal dysfunction in HF (OR: 1.853; 95% CI: 1.344-2.556; P < 0.001), and elevated PAGln levels were associated with a high risk of cardiovascular death in patients with chronic HF (HR: 2.049; 95% CI: 1.042-4.029; P = 0.038).

CONCLUSIONS

Elevated PAGln levels are an independent risk factor for HF and are associated with a higher risk of cardiovascular death. High PAGln levels could indicate renal dysfunction in HF patients. PAGln can be a valuable indicator of HF.

L-norvaline affects the proliferation of breast cancer cells based on the microbiome and metabolome analysis

AIMS

The altered fecal metabolites and microbiota might be involved in the development of breast cancer. We aimed to investigate the effect of differential metabolites on the proliferative activity of breast cancer cells.

METHODS AND RESULTS

We collected fecal samples from 14 breast cancer patients and 14 healthy subjects. Untargeted metabolomics analysis, short-chain fatty acid (SCFA) targeted analysis, and 16S rDNA sequencing was performed. The gut metabolite composition of patients changed significantly. Levels of norvaline, glucuronate, and galacturonate were lower in the Cancer group than in the Control (p < 0.05). 4-Methylcatechol and guaiacol increased (p < 0.05). Acetic acid and butyric acid were lower in the Cancer group than in the Control group (p < 0.05). Isobutyric acid and pentanoic acid were higher in the Cancer group than in the Control (p < 0.05). In the genus, the abundance of Rothia and Actinomyces increased in the Cancer group, compared with the Control group (p < 0.05). The differential microbiotas were clearly associated with differential metabolites but weakly with SCFAs. The abundance of Rothia and Actinomyces was markedly positively correlated with 4-methylcatechol and guaiacol (p < 0.05) and negatively correlated with norvaline (p < 0.05). L-norvaline inhibited the content of Arg-1 in a concentration-dependent manner. Compared with the L-norvaline or doxorubicin hydrochloride (DOX) group, the proliferation abilities of 4T1 cells were the lowest in the L-norvaline combined with DOX (p < 0.05). The apoptosis rate increased (p < 0.05).

CONCLUSIONS

Fecal metabolites and microbiota were significantly altered in breast cancer. Levels of differential metabolites (i.e., Norvaline) were significantly correlated with the abundance of differential microbiota. L-norvaline combined with DOX could clearly inhibit the proliferation activity of breast cancer cells.

SIGNIFICANCE AND IMPACT OF STUDY

This might provide clues to uncover potential biomarkers for breast cancer diagnosis and treatment.

Role of Gut Microbiota in Pulmonary Arterial Hypertension

Gut microbiota and its metabolites play an important role in maintaining host homeostasis. Pulmonary arterial hypertension (PAH) is a malignant clinical syndrome with a frightening mortality. Pulmonary vascular remodeling is an important feature of PAH, and its pathogenesis is not well established. With the progress of studies on intestinal microbes in different disease, cumulative evidence indicates that gut microbiota plays a major role in PAH pathophysiology. In this review, we will systematically summarize translational and preclinical data on the correlation between gut dysbiosis and PAH and investigate the role of gut dysbiosis in the causation of PAH. Then, we point out the potential significance of gut dysbiosis in the diagnosis and treatment of PAH as well as several problems that remain to be resolved in the field of gut dysbiosis and PAH. All of this knowledge of gut microbiome might pave the way for the extension of novel pathophysiological mechanisms, diagnosis, and targeted therapies for PAH.

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.

Knowledge Mapping of the Links Between the Gut Microbiota and Heart Failure: A Scientometric Investigation (2006–2021)

Background

There is considerable research value and extensive application perspectives to explore the link between gut microbiota and heart failure. The purpose of this study is to provide an overview of overall characteristics, evolutionary pathways, frontier research hotspots, and future trends in this field.

Methods

Research datasets were acquired from the Web of Science Core Collection (WoSCC) between January 1, 2006 and December 31, 2021. Three different analysis tools including one online platform, VOS viewer V1.6.17.0, and CiteSpace V5.8.R2 software were used in order to conduct collaboration network analysis, co-cited analysis, co-occurring analysis, and citation burst detection.

Results

A total of 873 publications in the WoSCC database met the requirement. The overall characteristics analysis showed that a steady growth trend in the number of publications and citations, with the predominant literature type being articles and the most frequent subject category being cardiac cardiovascular systems. The United States was the most prolific country and the center of national collaboration. Cleveland Clinic and Nathalie M. Delzenne provided the leading influence with publications, the cooperation between the institutes and authors were relatively weak. Moreover, gut microbiota, heart failure, risk factor, obesity, and inflammation were the keywords that appeared more frequently in the clustering analysis of reference co-citation and keyword co-occurrence. Burst detection analysis of top keywords showed that trimethylamine N-oxide (TMAO), bile acid, blood pressure, hypertension, and fermentation were the new research foci on the association between gut microbiota and heart failure. Strategies to improve gut microbiota hold promise as a new approach to treat heart failure.

Conclusion

The comprehensive bibliometric study indicates that the structured information may be helpful in understanding research trends in the link between gut microbiota and heart failure, and locating research hotspots and gaps in this domain, especially further advances in this field will lead to significant breakthroughs in the development of novel therapeutic tools for metabolic modulation of heart failure.

Diet-gut microbiota interactions on cardiovascular disease

Cardiovascular diseases (CVD) are a group of disorders of the heart and blood vessels and remain the leading cause of morbidity and mortality worldwide. Over the past decades, accumulating studies indicated that the gut microbiota, an indispensable "invisible organ", plays a vital role in human metabolism and disease states including CVD. Among many endogenous and exogenous factors that can impact gut microbial communities, the dietary nutrients emerge as an essential component of host-microbiota relationships that can be involved in CVD susceptibility. In this review, we summarize the major concepts of dietary modulation of the gut microbiota and the chief principles of the involvement of this microbiota in CVD development. We also discuss the mechanisms of diet-microbiota crosstalk that regulate CVD progression, including endotoxemia, inflammation, gut barrier dysfunction and lipid metabolism dysfunction. In addition, we describe how metabolites produced by the microbiota, including trimethylamine-N-oxide (TMAO), secondary bile acids (BAs), short chain fatty acids (SCFAs) as well as aromatic amino acids (AAAs) derived metabolites play a role in CVD pathogenesis. Finally, we present the potential dietary interventions which interacted with gut microbiota as novel preventive and therapeutic strategies for CVD management.

The Effect of Synbiotic Consumption on Serum NTproBNP, hsCRP and Blood Pressure in Patients With Chronic Heart Failure: A Randomized, Triple-Blind, Controlled Trial

Background

In recent years, there has been a positive attitude toward gut microbiota and its effect on cardiovascular diseases, including heart failure.

Objective

The purpose of this study was to evaluate the effect of synbiotics on left ventricular hypertrophy by measuring NT-proBNP, and their effect on blood pressure and hsCRP as an inflammatory biomarker in patients with chronic heart failure.

Design

In this triple-blind randomized clinical trial, 90 eligible patients were included in the study. They were randomly assigned to receive one capsule (500 mg) of synbiotics or placebo per day for 10 weeks. NTproBNP, hsCRP and blood pressure were measured at the beginning and end of the study. Statistical analysis was performed on 80 patients by using SPSS 24, and p < 0.05 as statistically significant.

Result

At the end of the study, the level of NT-proBNP decreased significantly in the synbiotic group compared to the placebo group (r = −256.55; P = 0.04). However, hsCRP increased in both groups as compared to the beginning of the study, but only in the placebo group the increase in hsCRP was significant (P = 0.01). The results showed that the changes in hs-CRP was not significant between the two groups. No statistically significant differences were observed in systolic and diastolic blood pressure between the two groups at the end of the intervention.

Conclusion

Synbiotics have favorable effect on cardiac hypertrophy index (NT-proBNP). Although the inflammatory factor increased in both groups, the significant increase in hsCRP in the placebo group could indicate the beneficial effects of synbiotics on the inflammatory status of these patients.

Clinical Trial Registration

https://en.irct.ir/user/trial/42905/view, identifier: IRCT20091114002709N52.

Naoxintong Capsule Alternates Gut Microbiota and Prevents Hyperlipidemia in High-Fat-Diet Fed Rats

Background: Naoxintong Capsule (NXT) is a formulated Traditional Chinese Medicine (TCM) widely applied in the treatment of cardiovascular and metabolic diseases, most of which are closely related to hyperlipidemia as a major risk factor. Given the current limited understandings to the role of gut microbiota in the lipid-lowering effect of NXT and other TCM products, this study investigated the regulation of gut microbiota and lipid metabolism by NXT, and their potential relationship. Methods: The chemical components of NXT were firstly analyzed with HPLC-MS method. In high fat diet (HFD)-fed rat models, as well as normal rats as control, the histopathological and biochemical changes of serum and liver were examined, including total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C). In addition, the gut microbiota community was analyzed using 16S rRNA sequencing technique, the fecal levels of gut microbiota related metabolites, including bile acids (BAs) and short chain fatty acids (SCFAs) were determined with HPLC-MS. The correlations of the clinical indicators and gut microbiota related indicators were then investigated statistically. Results: The results showed that NXT exerted potential preventive effect on hyperlipidemia. Specifically, NXT significantly reduced the body weight, TC, TG and LDL-C in serum, increased HDL-C in serum, reduced the TC and TG in liver, as well as protected liver. The body weight, serum lipid levels and liver function were all significantly alleviated. The gut microbiota of the HFD-fed rats was reconstituted with supplementation of NXT. The fecal levels of gut microbiota related metabolites, including BAs and SCFAs were also altered. The correlation between the gut microbiota and clinical/metabolomic parameters was then studied. As the result, the amount of propionic aicd, Firmicutes/Bacteroidetes ratio (F/B) and the relative abundance of Collinsella in feces are the most possibly potential therapeutic biomarkers of NXT. Conclusion: NXT was effective in regulation of gut microbiota and prevention of hyperlipidemia in HFD fed rats. The present work might provide novel insights into the anti-hyperlipidemia effect of TCM and afford new scientific evidence for clinical application of TCM.

Metabolomics Fingerprint Predicts Risk of Death in Dilated Cardiomyopathy and Heart Failure

Background

Heart failure (HF) is a leading cause of morbidity and mortality worldwide. Metabolomics may help refine risk assessment and potentially guide HF management, but dedicated studies are few. This study aims at stratifying the long-term risk of death in a cohort of patients affected by HF due to dilated cardiomyopathy (DCM) using serum metabolomics via nuclear magnetic resonance (NMR) spectroscopy.

Methods

A cohort of 106 patients with HF due to DCM, diagnosed and monitored between 1982 and 2011, were consecutively enrolled between 2010 and 2012, and a serum sample was collected from each participant. Each patient underwent half-yearly clinical assessments, and survival status at the last follow-up visit in 2019 was recorded. The NMR serum metabolomic profiles were retrospectively analyzed to evaluate the patient's risk of death. Overall, 26 patients died during the 8-years of the study.

Results

The metabolomic fingerprint at enrollment was powerful in discriminating patients who died (HR 5.71, p = 0.00002), even when adjusted for potential covariates. The outcome prediction of metabolomics surpassed that of N-terminal pro b-type natriuretic peptide (NT-proBNP) (HR 2.97, p = 0.005). Metabolomic fingerprinting was able to sub-stratify the risk of death in patients with both preserved/mid-range and reduced ejection fraction [hazard ratio (HR) 3.46, p = 0.03; HR 6.01, p = 0.004, respectively]. Metabolomics and left ventricular ejection fraction (LVEF), combined in a score, proved to be synergistic in predicting survival (HR 8.09, p = 0.0000004).

Conclusions

Metabolomic analysis via NMR enables fast and reproducible characterization of the serum metabolic fingerprint associated with poor prognosis in the HF setting. Our data suggest the importance of integrating several risk parameters to early identify HF patients at high-risk of poor outcomes.

Gut Microbiota and Metabolites in Atrial Fibrillation Patients and Their Changes after Catheter Ablation

The gut microbiota has been shown to be associated with multiple cardiovascular diseases, but there is little research on the gut microbiota and atrial fibrillation (AF); thus, how the gut microbiota and metabolites change in AF patients after catheter ablation is unclear. In this study, we used 16S rRNA high-throughput sequencing and nontargeted metabolomic detection to conduct horizontal and longitudinal analyses of the gut microbiota and metabolites of AF patients. Compared with a control group, species richness and diversity increased significantly in AF patients. Among them, opportunistic pathogenic bacteria, such as Klebsiella, Haemophilus, Streptococcus, and Enterococcus, were significantly increased, and symbiotic bacteria, such as Agathobacter and Butyrivibrio, were significantly reduced. After catheter ablation, intestinal symbiotic bacteria (Lactobacillus, Agathobacter, Lachnospira, etc.) were increased in most AF patients, while pathogenic bacteria (Ruminococcus, etc.) were reduced. Moreover, in AF patients, caffeine, which was negatively correlated with Klebsiella, was downregulated, and estradiol and ascorbic acid, which were positively correlated with Agathobacter, were also downregulated. After catheter ablation, citrulline, which was positively correlated with Ralstonia and Lactobacillus, was increased. Oleanolic acid, which was negatively correlated with Ralstonia was downregulated. In conclusion, our results not only show overall changes in the gut microbiota and metabolites in AF patients but also indicate their changes in the short term after catheter ablation. These data will provide novel possibilities for the future clinical diagnosis and treatment of AF.

IMPORTANCE Gut microbiota and metabolites play a very important role in human health and can not only assess human health but also treat and prevent diseases. We analyzed the characteristics of the microbiota and metabolites in the human gut and found the effect of disease on gut microbiota and metabolites, which may be of important value in the pathogenesis of atrial fibrillation. At the same time, we also observed dynamic changes in gut microbiota and metabolites with the intervention of catheter ablation, which was not available in previous studies.

A novel real-time TMAO detection method based on microbial electrochemical technology

Trimethylamine N-oxide (TMAO) is considered to be a novel biomarker of cardiovascular diseases. However, the traditional TMAO detection method has failed to meet the requirements of real-time and point-of-care tests. Herein, a novel TMAO detection method based on microbial electrochemical technology is established, which realizes the direct conversion of TMAO concentration into electrical signals. Attached Shewanella loihica PV-4 was first proven to be capable of simultaneous inward extracellular electron transfer and TMAO reduction. The TMAO detection method showed a wide linear range of 0 to 250 μM, a high sensitivity of 23.92 μA/mM, and a low limit of detection of 5.96 μM. In addition, the TMAO detection process was accomplished within 600 s, with an acceptable accuracy of 90% in the real serum, showing high feasibility in clinical applications.

Heart Failure Severity Closely Correlates with Intestinal Dysbiosis and Subsequent Metabolomic Alterations

Growing evidence suggests an altered gut microbiome in patients with heart failure (HF). However, the exact interrelationship between microbiota, HF, and its consequences on the metabolome are still unknown. We thus aimed here to decipher the association between the severity and progression of HF and the gut microbiome composition and circulating metabolites. Using a mouse model of transverse aortic constriction (TAC), gut bacterial diversity was found to be significantly lower in mice as early as day 7 post-TAC compared to Sham controls (p = 0.03), with a gradual progressive decrease in alpha-diversity on days 7, 14, and 42 (p = 0.014, p = 0.0016, p = 0.0021) compared to day 0, which coincided with compensated hypertrophy, maladaptive hypertrophy, and overtly failing hearts, respectively. Strikingly, segregated analysis based on the severity of the cardiac dysfunction (EF < 40% vs. EF 40−55%) manifested marked differences in the abundance and the grouping of several taxa. Multivariate analysis of plasma metabolites and bacterial diversity produced a strong correlation of metabolic alterations, such as reduced short-chain fatty acids and an increase in primary bile acids, with a differential abundance of distinct bacteria in HF. In conclusion, we showed that HF begets HF, likely via a vicious cycle of an altered microbiome and metabolic products.

Bacterial diversity in the intestinal mucosa of heart failure rats treated with Sini Decoction

Background

Sini Decoction (SND), a classic Chinese medicine prescription, has been proved to have a good effect on heart failure (HF), whereas its underlying mechanism is still unclear. In order to explore the therapeutic mechanism of SND, we combined with 16S rRNA gene sequencing to analyze the composition of gut microflora in rats with HF.

Material and methods

Twenty Sprague–Dawley (SD) rats were divided into four groups (n = 5): normal group, model group, SND treatment group (SNT group), and metoprolol (Met) treatment group (Meto group). All the rats except the normal group were intraperitoneally injected with doxorubicin (concentration 2 mg/mL, dose 0.15 mL/100 g) once a week to induce HF. After successfully modeling, SND and Met were gavaged to rats, respectively. After the treatment period, blood was collected for hematological analyses, myocardial tissue and colon tissues were collected for Hematoxylin–Eosin (H&E) staining, and mucosal scrapings were collected for Illumina Miseq high-throughput sequencing.

Results

Echocardiographic results suggested that both left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS) in Model rats decreased compared with normal rats. The results of H&E staining showed that compared with the model group, the structures of myocardial tissue and colon tissue in the SNT group and Meto group showed a recovery trend. Alpha results showed that the model group had higher species diversity and richness compared with the normal group. After treatment, the richness and diversity of intestinal bacteria in the SNT group were significantly restored, and Met also showed the effect of adjusting bacterial diversity, but its effect on bacterial richness was not ideal. At the Family level, we found that the number of several bacteria associated with HF in the model group increased significantly. Excitingly, SND and Met had shown positive effects in restoring these HF-associated bacteria. Similarly, the results of Linear discriminant analysis (LDA) showed that both SND and Met could reduce the accumulation of bacteria in the model group caused by HF.

Conclusion

Collectively, SND can improve HF by regulating the intestinal flora. This will provide new ideas for the clinical treatment of patients with HF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03575-4.

The Contribution of Gut Microbiota and Endothelial Dysfunction in the Development of Arterial Hypertension in Animal Models and in Humans

The maintenance of the physiological values of blood pressure is closely related to unchangeable factors (genetic predisposition or pathological alterations) but also to modifiable factors (dietary fat and salt, sedentary lifestyle, overweight, inappropriate combinations of drugs, alcohol abuse, smoking and use of psychogenic substances). Hypertension is usually characterized by the presence of a chronic increase in systemic blood pressure above the threshold value and is an important risk factor for cardiovascular disease, including myocardial infarction, stroke, micro- and macro-vascular diseases. Hypertension is closely related to functional changes in the endothelium, such as an altered production of vasoconstrictive and vasodilator substances, which lead to an increase in vascular resistance. These alterations make the endothelial tissue unresponsive to autocrine and paracrine stimuli, initially determining an adaptive response, which over time lead to an increase in risk or disease. The gut microbiota is composed of a highly diverse bacterial population of approximately 10¹⁴ bacteria. A balanced intestinal microbiota preserves the digestive and absorbent functions of the intestine, protecting from pathogens and toxic metabolites in the circulation and reducing the onset of various diseases. The gut microbiota has been shown to produce unique metabolites potentially important in the generation of hypertension and endothelial dysfunction. This review highlights the close connection between hypertension, endothelial dysfunction and gut microbiota.

Physiologically Inspired Mucin Coated Escherichia coli Nissle 1917 Enhances Biotherapy by Regulating the Pathological Microenvironment to Improve Intestinal Colonization

The delivery of probiotics to the microbiota is a promising method to prevent and treat diseases. However, oral probiotics will suffer from gastrointestinal insults, especially the pathological microenvironment of inflammatory diseases such as reactive oxygen species (ROS) and the exhausted mucus layer, which can limit their survival and colonization in the intestinal tract. Inspired by the fact that probiotics colonized and grew in the mucus layer under physiological conditions, we developed a strategy for a super probiotic (EcN@TA-Ca²⁺@Mucin) coated with tannic acid and mucin via layer-by-layer technology. We demonstrated that mucin endows probiotics with superior resistance to the harsh environment of the gastrointestinal tract and with strong adhesiveness to the intestine through its interaction with mucus, which enhanced colonization and growth of probiotics in the mucus layer without removing the coating. Moreover, EcN@TA-Ca²⁺@Mucin can distinctly down-regulate inflammation with ROS scavenging and reduce the side effects of bacterial translocation in inflammatory bowel diseases, increasing the abundance and diversity of the gut microflora. We envision that it is a powerful platform to improve the colonization of probiotics by regulating the pathological microenvironment, which is expected to provide an important perspective for applying the intestinal colonization of probiotics to treat a variety of diseases.

Cardiac Cachexia: Unaddressed Aspect in Cancer Patients

Tumor-derived cachectic factors such as proinflammatory cytokines and neuromodulators not only affect skeletal muscle but also affect other organs, including the heart, in the form of cardiac muscle atrophy, fibrosis, and eventual cardiac dysfunction, resulting in poor quality of life and reduced survival. This article reviews the holistic approaches of existing diagnostic, pathophysiological, and multimodal therapeutic interventions targeting the molecular mechanisms that are responsible for cancer-induced cardiac cachexia. The major drivers of cardiac muscle wasting in cancer patients are autophagy activation by the cytokine-NFkB, TGF β-SMAD³, and angiotensin II-SOCE-STIM-Ca²⁺ pathways. A lack of diagnostic markers and standard treatment protocols hinder the early diagnosis of cardiac dysfunction and the initiation of preventive measures. However, some novel therapeutic strategies, including the use of Withaferin A, have shown promising results in experimental models, but Withaferin A’s effectiveness in human remains to be verified. The combined efforts of cardiologists and oncologists would help to identify cost effective and feasible solutions to restore cardiac function and to increase the survival potential of cancer patients.

Promising Antioxidative Effect of Berberine in Cardiovascular Diseases

Berberine (BBR), an important quaternary benzylisoquinoline alkaloid, has been used in Chinese traditional medicine for over 3,000 years. BBR has been shown in both traditional and modern medicine to have a wide range of pharmacological actions, including hypoglycemic, hypolipidemic, anti-obesity, hepatoprotective, anti-inflammatory, and antioxidant activities. The unregulated reaction chain induced by oxidative stress as a crucial mechanism result in myocardial damage, which is involved in the pathogenesis and progression of many cardiovascular diseases (CVDs). Numerous researches have established that BBR protects myocardium and may be beneficial in the treatment of CVDs. Given that the pivotal role of oxidative stress in CVDs, the pharmacological effects of BBR in the treatment and/or management of CVDs have strongly attracted the attention of scholars. Therefore, this review sums up the prevention and treatment mechanisms of BBR in CVDs from in vitro, in vivo, and finally to the clinical field trials timely. We summarized the antioxidant stress of BBR in the management of coronary atherosclerosis and myocardial ischemia/reperfusion; it also analyzes the pathogenesis of oxidative stress in arrhythmia and heart failure and the therapeutic effects of BBR. In short, BBR is a hopeful drug candidate for the treatment of CVDs, which can intervene in the process of CVDs from multiple angles and different aspects. Therefore, if we want to apply it to the clinic on a large scale, more comprehensive, intensive, and detailed researches are needed to be carried out to clarify the molecular mechanism and targets of BBR.

Pig and Mouse Models of Hyperlipidemia and Atherosclerosis

Atherosclerosis is a chronic inflammatory disorder that is the underlying cause of most cardiovascular disease. Resident cells of the artery wall and cells of the immune system participate in atherogenesis. This process is influenced by plasma lipoproteins, genetics, and the hemodynamics of the blood flow in the artery. A variety of animal models have been used to study the pathophysiology and mechanisms that contribute to atherosclerotic lesion formation. No model is ideal as each has its own advantages and limitations with respect to manipulation of the atherogenic process and modeling human atherosclerosis and lipoprotein profile. In this chapter we will discuss pig and mouse models of experimental atherosclerosis. The similarity of pig lipoprotein metabolism and the pathophysiology of the lesions in these animals with that of humans is a major advantage. While a few genetically engineered pig models have been generated, the ease of genetic manipulation in mice and the relatively short time frame for the development of atherosclerosis has made them the most extensively used model. Newer approaches to induce hypercholesterolemia in mice have been developed that do not require germline modifications. These approaches will facilitate studies on atherogenic mechanisms.

Intestinal barrier dysfunction is associated with elevated right atrial pressure in patients with advanced decompensated heart failure

We prospectively performed serial differential sugar absorption test in 29 consecutively consented patients with advanced decompensated heart failure admitted to the heart failure intensive care unit for hemodynamically-guided therapy. We observed that intestinal barrier function was significantly impaired in our study cohort, and increased intestinal permeability was associated with elevated right atrial pressure and poorer prognosis yet without any association with systemic levels of the gut microbial metabolite, trimethylamine N-oxide (TMAO) or intestinal fatty acid binding protein that were thought to be indicative of intestinal abnormalities.

Involvement of Abnormal Gut Microbiota Composition and Function in Doxorubicin-Induced Cardiotoxicity

Objectives

Doxorubicin (Dox), a chemotherapeutic anthracycline agent for the treatment of a variety of malignancies, has a limitation in clinical application for dose-dependent cardiotoxicity. The purpose of this study was to explore the relationship between the composition/function of the gut microbiota and Dox-induced cardiotoxicity (DIC).

Methods

C57BL/6J mice were injected intraperitoneally with 15 mg/kg of Dox, with or without antibiotics (Abs) administration. The M-mode echocardiograms were performed to assess cardiac function. The histopathological analysis was conducted by H&E staining and TUNEL kit assay. The serum levels of creatine kinase (CK), CK-MB (CK-MB), lactic dehydrogenase (LDH), and cardiac troponin T (cTnT) were analyzed by an automatic biochemical analyzer. 16S rRNA gene and metagenomic sequencing of fecal samples were used to explore the gut microbiota composition and function.

Key Findings

Dox caused left ventricular (LV) dilation and reduced LV contractility. The levels of cardiomyocyte apoptosis and myocardial enzymes were elevated in Dox-treated mice compared with the control (Con) group. 16S rRNA gene sequencing results revealed significant differences in microbial composition between the two groups. In the Dox group, the relative abundances of Allobaculum, Muribaculum, and Lachnoclostridium were significantly decreased, whereas Faecalibaculum, Dubosiella, and Lachnospiraceae were significantly increased compared with the Con group at the genus level. Functional enrichment with Cluster of orthologous groups of proteins (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the Dox mice displayed different clusters of cellular processes and metabolism from the Con mice. The different species and their functions between the two groups were associated with the clinical factors of cardiac enzymes. Moreover, depletion of the gut microbiota could alleviate Dox-induced myocardial injury and cardiomyocyte apoptosis.

Conclusions

The study here shows that composition imbalance and functional changes of the gut microbiota can be one of the etiological mechanisms underlying DIC. The gut microbiota may serve as new targets for the treatment of cardiotoxicity and cardiovascular diseases.

Shenqi Yanshen Formula (SQYSF) protects against chronic kidney disease by modulating gut microbiota

In this study, we make an elucidation toward both the therapeutic effect and the mechanism of Shenqi Yanshen Formula (SQYSF) to chronic kidney disease (CKD). CKD mouse model was established and achieved in a way of adenine (200 mg/kg) perfusion. Six weeks later, those mice in the model group were fed with SQYSF (3.60 g/kg/day) every day (the captopril group was given 12.5 mg/kg/day by gavage every day, and control group and the model group were both given the gavage of equal volumes of normal saline); 4 weeks after the administration, we had our detection to physiological indicators of mice, performed ELISA assay to detect inflammatory factor expressions, then assay of 16S sequencing was used to reveal the difference of intestinal flora. Our results showed that after SQYSF treatment, both the expressions of serum creatinine (Scr) and blood urea nitrogen (BUN) came with a significant decline, indicating the outstanding performances of SQYSF in alleviating impairment in renal function and elevating mice’s physiological function. SQYSF significantly reduced the degree of renal fibrosis in CKD mice, and remarkably down-regulated the expressions of toll-like receptor 5 (TLR5), nuclear factor-kappaB (NF-κb), p65, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6. Additionally, SQYSF has more than ability in significantly changing the composition in mice’s intestinal flora, but also in greatly increasing the abundance of Succinivibrionaceae and Aeromonadales in the mouse intestine. This study clarified the therapeutic effect of SQYSF on CKD and regulation of inflammatory factors and intestinal flora, and provided new ideas for treatment on CKD.

Alterations of the Gut Microbiota in Patients With Severe Chronic Heart Failure

Chronic heart failure (CHF) is the final outcome of almost all forms of cardiovascular diseases, remaining the main cause of mortality worldwide. Accumulating evidence is focused on the roles of gut microbial community in cardiovascular disease, but few studies have unveiled the alterations and further directions of gut microbiota in severe CHF patients. Aimed to investigate this deficiency, fecal samples from 29 CHF patients diagnosed with NYHA Class III-IV and 30 healthy controls were collected and then analyzed using bacterial 16S rRNA gene sequencing. As a result, there were many significant differences between the two groups. Firstly, the phylum Firmicutes was found to be remarkably decreased in severe CHF patients, and the phylum Proteobacteria was the second most abundant phyla in severe CHF patients instead of phylum Bacteroides strangely. Secondly, the α diversity indices such as chao1, PD-whole-tree and Shannon indices were significantly decreased in the severe CHF versus the control group, as well as the notable difference in β-diversity between the two groups. Thirdly, our result revealed a remarkable decrease in the abundance of the short-chain fatty acids (SCFA)-producing bacteria including genera Ruminococcaceae UCG-004, Ruminococcaceae UCG-002, Lachnospiraceae FCS020 group, Dialister and the increased abundance of the genera in Enterococcus and Enterococcaceae with an increased production of lactic acid. Finally, the alternation of the gut microbiota was presumably associated with the function including Cell cycle control, cell division, chromosome partitioning, Amino acid transport and metabolism and Carbohydrate transport and metabolism through SCFA pathway. Our findings provide the direction and theoretical knowledge for the regulation of gut flora in the treatment of severe CHF.

Trimethylamine N-Oxide in Heart Failure: A Meta-Analysis of Prognostic Value

Objective

The present study aimed to explore the prognostic value of trimethylamine N-oxide (TMAO) in heart failure (HF).

Methods

PubMed, Excerpta Medica Database (EMBASE), Cochrane Library, Web of Science, Wanfang Database, SINOMED, China Science and Technology Journal Database (VIP), and China National Knowledge Infrastructure (CNKI) were searched up to June 1, 2021. Studies recording the major adverse cardiovascular events (MACEs) or all-cause mortality in HF patients and their circulating TMAO concentrations were included. Meta-analysis was performed using Stata 13.0.

Results

Ten articles (12 studies) involving 13,425 participants from 2014 to 2021 were considered. Compared to low-level TMAO, elevated TMAO was correlated with MACEs and all-cause mortality in HF (RR: 1.28, 95% CI: 1.17, 1.39, P < 0.0001, random-effects model and RR: 1.35, 95% CI: 1.28, 1.42, P < 0.0001, random-effects model, respectively). Consistent results were obtained in all examined subgroups as well as in the sensitivity analysis.

Conclusion

Elevated TMAO may be an adverse prognostic indicator in patients with HF.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=267208

Metabolic Reprogramming, Gut Dysbiosis, and Nutrition Intervention in Canine Heart Disease

This review provides a state-of-the-art overview on recent advances in systems biology in canine cardiac disease, with a focus on our current understanding of bioenergetics and amino acid metabolism in myxomatous mitral valve disease (MMVD). Cross-species comparison is drawn to highlight the similarities between human and canine heart diseases. The adult mammalian heart exhibits a remarkable metabolic flexibility and shifts its energy substrate preference according to different physiological and pathological conditions. The failing heart suffers up to 40% ATP deficit and is compared to an engine running out of fuel. Bioenergetics and metabolic readaptations are among the major research topics in cardiac research today. Myocardial energy metabolism consists of three interconnected components: substrate utilization, oxidative phosphorylation, and ATP transport and utilization. Any disruption or uncoupling of these processes can result in deranged energy metabolism leading to heart failure (HF). The review describes the changes occurring in each of the three components of energy metabolism in MMVD and HF. It also provides an overview on the changes in circulating and myocardial glutathione, taurine, carnitines, branched-chain amino acid catabolism and tryptophan metabolic pathways. In addition, the review summarizes the potential role of the gut microbiome in MMVD and HF. As our knowledge and understanding in these molecular and metabolic processes increase, it becomes possible to use nutrition to address these changes and to slow the progression of the common heart diseases in dogs.

The potential of probiotics in the amelioration of hyperuricemia

Hyperuricemia is a common disease caused by metabolic disorders or the excessive intake of high-purine foods. Persistent hyperuricemia in extreme cases induces gout, and asymptomatic hyperuricemia is probably linked to other metabolic diseases, such as hypertension. The typical damage caused by asymptomatic hyperuricemia includes inflammation, oxidative stress and gut dysbiosis. Probiotics have broad potential applications as food additives, not as drug therapies, in the amelioration of hyperuricemia. In this review, we describe novel methods for potential hyperuricemia amelioration with probiotics. The pathways through which probiotics may ameliorate hyperuricemia are discussed, including the decrease in uric acid production through purine assimilation and XOD (xanthine oxidase) inhibition as well as enhanced excretion of uric acid production by promoting ABCG2 (ATP binding cassette subfamily G member 2) activity, respectively. Three possible probiotic-related therapeutic pathways for alleviating the syndrome of hyperuricemia are also summarized. The first mechanism is to alleviate the oxidation and inflammation induced by hyperuricemia through the inhibition of NLRP3 inflammasome, the second is to restore damaged intestinal epithelium barriers and prevent gut microbiota dysbiosis, and the third is to enhance the innate immune system by increasing the secretion of immunoglobulin A (sIgA) to resist the stimulus by hyperuricemia. We propose that future research should focus on superior strain resource isolation and insight into the cause-effect mechanisms of probiotics for hyperuricemia amelioration. The safety and effects of the application of probiotics in clinical use also need verification.

Resistance and Endurance Exercise Training Induce Differential Changes in Gut Microbiota Composition in Murine Models

Background: The effect of resistance training on gut microbiota composition has not been explored, despite the evidence about endurance exercise. The aim of this study was to compare the effect of resistance and endurance training on gut microbiota composition in mice.

Methods: Cecal samples were collected from 26 C57BL/6N mice, divided into three groups: sedentary (CTL), endurance training on a treadmill (END), and resistance training on a vertical ladder (RES). After 2 weeks of adaption, mice were trained for 4 weeks, 5 days/week. Maximal endurance and resistance capacity test were performed before and after training. Genomic DNA was extracted and 16S Ribosomal RNA sequenced for metagenomics analysis. The percentages for each phylum, class, order, family, or genus/species were obtained using an open-source bioinformatics pipeline.

Results: END showed higher diversity and evenness. Significant differences among groups in microbiota composition were only observed at genera and species level. END showed a significantly higher relative abundance of Desulfovibrio and Desulfovibrio sp., while Clostridium and C. cocleatum where higher for RES. Trained mice showed significantly lower relative abundance of Ruminococcus gnavus and higher of the genus Parabacteroides compared to CTL. We explored the relationship between relative taxa abundance and maximal endurance and resistance capacities after the training period. Lachnospiraceae and Lactobacillaceae families were negatively associated with endurance performance, while several taxa, including Prevotellaceae family, Prevotella genus, and Akkermansia muciniphila, were positively correlated. About resistance performance, Desulfovibrio sp. was negatively correlated, while Alistipes showed a positive correlation.

Conclusion: Resistance and endurance training differentially modify gut microbiota composition in mice, under a high-controlled environment. Interestingly, taxa associated with anti- and proinflammatory responses presented the same pattern after both models of exercise. Furthermore, the abundance of several taxa was differently related to maximal endurance or resistance performance, most of them did not respond to training.