Gut Microbiota Promote Angiotensin II-Induced Arterial Hypertension and Vascular Dysfunction

Yi-Shen-Hua-Shi regulates intestinal microbiota dysbiosis and protects against proteinuria in patients with chronic kidney disease: a randomized controlled study

CONTEXT

Yi-Shen-Hua-Shi (YSHS) is a traditional Chinese medicine that treats chronic kidney disease (CKD). However, its efficacy in reducing proteinuria and underlying mechanisms is unknown.

OBJECTIVE

This single-center randomized controlled trial explored whether YSHS could improve proteinuria and modulate the gut microbiota.

MATERIALS AND METHODS

120 CKD patients were enrolled and randomized to receive the renin-angiotensin-aldosterone system (RAAS) inhibitor plus YSHS (n = 56) or RAAS inhibitor (n = 47) alone for 4 months, and 103 patients completed the study. We collected baseline and follow-up fecal samples and clinical outcomes from participants. Total bacterial DNA was extracted, and the fecal microbiome was analyzed using bioinformatics.

RESULTS

Patients in the intervention group had a significantly higher decrease in 24-h proteinuria. After 4 months of the YSHS intervention, the relative abundance of bacteria that have beneficial effects on the body, such as Faecalibacterium, Lachnospiraceae, Lachnoclostridium, and Sutterella increased significantly, while pathogenic bacteria such as the Eggerthella and Clostridium innocuum group decreased. However, we could not find these changes in the control group. Redundancy analysis showed that the decline in 24-h proteinuria during follow-up was significantly correlated with various taxa of gut bacteria, such as Lachnospiraceae and the Lachnoclostridium genus in the YSHS group. KEGG analysis also showed the potential role of YSHS in regulating glycan, lipid, and vitamin metabolism.

DISCUSSION AND CONCLUSION

The YSHS granule reduced proteinuria associated with mitigating intestinal microbiota dysbiosis in CKD patients. The definite mechanisms of YSHS to improve proteinuria need to be further explored.

TRIAL REGISTRATION

ChiCTR2300076136, retrospectively registered.

Heart failure-induced microbial dysbiosis contributes to colonic tumour formation in mice

AIMS

Heart failure (HF) and cancer are the leading causes of death worldwide. Epidemiological studies revealed that HF patients are prone to develop cancer. Preclinical studies provided some insights into this connection, but the exact mechanisms remain elusive. In colorectal cancer (CRC), gut microbial dysbiosis is linked to cancer progression and recent studies have shown that HF patients display microbial dysbiosis. This current study focussed on the effects of HF-induced microbial dysbiosis on colonic tumour formation.

METHODS AND RESULTS

C57BL/6J mice were subjected to myocardial infarction (MI), with sham surgery as control. After six weeks faeces were collected, processed for 16 s rRNA sequencing, and pooled for faecal microbiota transplantation. CRC tumour growth was provoked in germ-free mice by treating them with Azoxymethane/Dextran sodium sulphate. The CRC mice were transplanted with faeces from MI or sham mice. MI-induced HF resulted in microbial dysbiosis, characterized by a decreased α-diversity and microbial alterations on the genus level, several of which have been associated with CRC. We then performed faecal microbiota transplantation with faeces from HF mice in CRC mice, which resulted in a higher endoscopic disease score and an increase in the number of tumours in CRC mice.

CONCLUSION

We demonstrated that MI-induced HF contributes to colonic tumour formation by altering the gut microbiota composition, providing a mechanistic explanation for the observed association between HF and increased risk for cancer. Targeting the microbiome may present as a tool to mitigate HF-associated co-morbidities, especially cancer.

Microbiome interactions with different risk factors in development of myocardial infarction

Among all non-communicable diseases, Cardiovascular Diseases (CVDs) stand as the leading global cause of mortality. Within this spectrum, Myocardial Infarction (MI) strikingly accounts for over 15 % of all deaths. The intricate web of risk factors for MI, comprising family history, tobacco use, oral health, hypertension, nutritional pattern, and microbial infections, is firmly influenced by the human gut and oral microbiota, their diversity, richness, and dysbiosis, along with their respective metabolites. Host genetic factors, especially allelic variations in signaling and inflammatory markers, greatly affect the progression or severity of the disease. Despite the established significance of the human microbiome-nutrient-metabolite interplay in associations with CVDs, the unexplored terrain of the gut-heart-oral axis has risen as a critical knowledge gap. Moreover, the pivotal role of the microbiome and the complex interplay with host genetics, compounded by age-related changes, emerges as an area of vital importance in the development of MI. In addition, a distinctive disease susceptibility and severity influenced by gender-based or ancestral differences, adds a crucial insights to the association with increased mortality. Here, we aimed to provide an overview on interactions of microbiome (oral and gut) with major risk factors (tobacco use, alcohol consumption, diet, hypertension host genetics, gender, and aging) in the development of MI and therapeutic regulation.

Unlocking the gut-heart axis: exploring the role of gut microbiota in cardiovascular health and disease

Introduction

Gut microbiota has emerged as a pivotal player in cardiovascular health and disease, extending its influence beyond the gut through intricate metabolic processes and interactions with the immune system. Accumulating evidence supports a significant association between gut microbiota and cardiovascular diseases such as atherosclerosis, hypertension, and heart failure. Dietary patterns have been identified as key factors shaping the composition of the gut microbiota and exerting notable impacts on cardiovascular health. Probiotics and prebiotics have shown promise in mitigating the risks of cardiovascular disease by modulating key cardiovascular parameters. Faecal microbiota transplantation (FMT) has recently emerged as a novel and intriguing therapeutic strategy.

Aim

This review paper aims to explore and elucidate the multifaceted role of gut microbiota in cardiovascular health. It will also address the prevailing challenges and limitations in gut microbiota studies, emphasizing the importance of future research in overcoming these obstacles to expand our understanding of the gut-heart axis.

Materials and methods

A comprehensive literature search was conducted using various databases including ClinicalTrials, Google Scholar, PubMed, ScienceDirect, MEDLINE, and Ovid Resources. The search strategy included utilizing keywords such as "Gut microbiota," "Randomized controlled trials (RCTs)," "Gut-heart axis," "Dysbiosis," "Diet," "Probiotics," "Prebiotics," "Faecal Microbiota transplantation," "cardiovascular disease," "Meta-analyses," and other compatible terms thereof. Only articles written in English were considered, and selection criteria included relevance to the research objectives, reasonable sample sizes, and robust methodology. In addition to the identified articles, meta-analyses, animal models and studies, and references from the selected articles were also examined to ensure a comprehensive review of the literature.

Results

Dietary patterns exert a significant influence on the composition of the gut microbiota, and certain diets, such as the Mediterranean diet, have been associated with a favourable gut microbiota profile and a reduced risk of cardiovascular disease (CVD). Probiotics and prebiotics have emerged as potential interventions to mitigate CVD risks by modulating blood pressure, glycemic control, lipid profiles, and gut dysbiosis. Another innovative therapeutic approach is FMT, which involves transferring faecal material from a healthy donor to restore a balanced gut microbiota. FMT holds promise for improving cardiometabolic parameters in individuals with CVD, although further research is needed to elucidate its precise mechanisms and assess its effectiveness.

Conclusion

The gut microbiota is emerging as a potential therapeutic target for CVD prevention and management. However, current research has limitations, including the need for larger and more diverse studies, the challenges of establishing causality, and concerns regarding the long-term consequences and safety of gut microbiota modulation. Despite these limitations, understanding the gut-heart axis holds promise for the development of personalized therapies and interventions for cardiovascular health. Further research is needed to expand our knowledge and address the ethical and safety issues associated with gut microbiota modification.

The role of the brain renin-angiotensin system in Parkinson´s disease

The renin-angiotensin system (RAS) was classically considered a circulating hormonal system that regulates blood pressure. However, different tissues and organs, including the brain, have a local paracrine RAS. Mutual regulation between the dopaminergic system and RAS has been observed in several tissues. Dysregulation of these interactions leads to renal and cardiovascular diseases, as well as progression of dopaminergic neuron degeneration in a major brain center of dopamine/angiotensin interaction such as the nigrostriatal system. A decrease in the dopaminergic function induces upregulation of the angiotensin type-1 (AT1) receptor activity, leading to recovery of dopamine levels. However, AT1 receptor overactivity in dopaminergic neurons and microglial cells upregulates the cellular NADPH-oxidase-superoxide axis and Ca2+ release, which mediate several key events in oxidative stress, neuroinflammation, and α-synuclein aggregation, involved in Parkinson's disease (PD) pathogenesis. An intraneuronal antioxidative/anti-inflammatory RAS counteracts the effects of the pro-oxidative AT1 receptor overactivity. Consistent with this, an imbalance in RAS activity towards the pro-oxidative/pro-inflammatory AT1 receptor axis has been observed in the substantia nigra and striatum of several animal models of high vulnerability to dopaminergic degeneration. Interestingly, autoantibodies against angiotensin-converting enzyme 2 and AT1 receptors are increased in PD models and PD patients and contribute to blood-brain barrier (BBB) dysregulation and nigrostriatal pro-inflammatory RAS upregulation. Therapeutic strategies addressed to the modulation of brain RAS, by AT1 receptor blockers (ARBs) and/or activation of the antioxidative axis (AT2, Mas receptors), may be neuroprotective for individuals with a high risk of developing PD or in prodromal stages of PD to reduce progression of the disease.

Vascular dysfunction and arterial hypertension in experimental celiac disease are mediated by gut-derived inflammation and oxidative stress

AIMS

We examined the cardiovascular effects of celiac disease (CeD) in a humanized mouse model, with a focus on vascular inflammation, endothelial dysfunction, and oxidative stress.

METHODS AND RESULTS

NOD.DQ8 mice genetically predisposed to CeD were subjected to a diet regime and oral gavage to induce the disease (gluten group vs. control). We tested vascular function, confirmed disease indicators, and evaluated inflammation and oxidative stress in various tissues. Plasma proteome profiling was also performed. CeD markers were confirmed in the gluten group, indicating increased blood pressure and impaired vascular relaxation. Pro-inflammatory genes were upregulated in this group, with increased CD11b+ myeloid cell infiltration and oxidative stress parameters observed in aortic and heart tissue. However, heart function remained unaffected. Plasma proteomics suggested the cytokine interleukin-17A (IL-17A) as a link between gut and vascular inflammation. Cardiovascular complications were reversed by adopting a gluten-free diet.

CONCLUSION

Our study sheds light in the heightened cardiovascular risk associated with active CeD, revealing a gut-to-cardiovascular inflammatory axis potentially mediated by immune cell infiltration and IL-17A. These findings augment our understanding of the link between CeD and cardiovascular disease providing clinically relevant insight into the underlying mechanism. Furthermore, our discovery that cardiovascular complications can be reversed by a gluten-free diet underscores a critical role for dietary interventions in mitigating cardiovascular risks associated with CeD.

Salt Sensitivity: Causes, Consequences, and Recent Advances

Salt (sodium chloride) is an essential nutrient required to maintain physiological functions. However, for most people, daily salt intake far exceeds their physiological need and is habitually greater than recommended upper thresholds. Excess salt intake leads to elevation in blood pressure which drives cardiovascular morbidity and mortality. Indeed, excessive salt intake is estimated to be responsible for ≈5 million deaths per year globally. For approximately one-third of otherwise healthy individuals (and >50% of those with hypertension), the effect of salt intake on blood pressure elevation is exaggerated; such people are categorized as salt sensitive and salt sensitivity of blood pressure is considered an independent risk factor for cardiovascular disease and death. The prevalence of salt sensitivity is higher in women than in men and, in both, increases with age. This narrative review considers the foundational concepts of salt sensitivity and the underlying effector systems that cause salt sensitivity. We also consider recent updates in preclinical and clinical research that are revealing new modifying factors that determine the blood pressure response to high salt intake.

Oral Cardiac Drug-Gut Microbiota Interaction in Chronic Heart Failure Patients: An Emerging Association

Regardless of the currently proposed best medical treatment for heart failure patients, the morbidity and mortality rates remain high. This is due to several reasons, including the interaction between oral cardiac drug administration and gut microbiota. The relation between drugs (especially antibiotics) and gut microbiota is well established, but it is also known that more than 24% of non-antibiotic drugs affect gut microbiota, altering the microbe's environment and its metabolic products. Heart failure treatment lies mainly in the blockage of neuro-humoral hyper-activation. There is debate as to whether the administration of heart-failure-specific drugs can totally block this hyper-activation, or whether the so-called intestinal dysbiosis that is commonly observed in this group of patients can affect their action. Although there are several reports indicating a strong relation between drug-gut microbiota interplay, little is known about this relation to oral cardiac drugs in chronic heart failure. In this review, we review the contemporary data on a topic that is in its infancy. We aim to produce scientific thoughts and questions and provide reasoning for further clinical investigation.

Gut microbiota and risk of endocarditis: a bidirectional Mendelian randomization study

Background

The associations between gut microbiota and cardiovascular disease have been reported in previous studies. However, the relationship between gut microbiota and endocarditis remains unclear.

Methods

A bidirectional Mendelian randomization (MR) study was performed to detect the association between gut microbiota and endocarditis. Inverse variance weighted (IVW) method was considered the main result. Simultaneously, heterogeneity and pleiotropy tests were conducted.

Results

Our study suggests that family Victivallaceae (p = 0.020), genus Eubacterium fissicatena group (p = 0.047), genus Escherichia Shigella (p = 0.024), genus Peptococcus (p = 0.028) and genus Sellimonas (p = 0.005) play protective roles in endocarditis. Two microbial taxa, including genus Blautia (p = 0.006) and genus Ruminococcus2 (p = 0.024) increase the risk of endocarditis. At the same time, endocarditis has a negative effect on genus Eubacterium fissicatena group (p = 0.048). Besides, no heterogeneity or pleiotropy was found in this study.

Conclusion

Our study emphasized the certain role of specific gut microbiota in patients with endocarditis and clarified the negative effect of endocarditis on gut microbiota.

Brain-Splenic Immune System Interactions in Hypertension: Cellular and Molecular Mechanisms

Hypertension represents a major worldwide cause of death and disability, and it is becoming increasingly clear that available therapies are not sufficient to reduce the risk of major cardiovascular events. Various mechanisms contribute to blood pressure increase: neurohormonal activation, autonomic nervous system imbalance, and immune activation. Of note, the brain is an important regulator of blood pressure levels; it recognizes the peripheral perturbation and organizes a reflex response by modulating immune system and hormonal release to attempt at restoring the homeostasis. The connection between the brain and peripheral organs is mediated by the autonomic nervous system, which also modulates immune and inflammatory responses. Interestingly, an increased autonomic nervous system activity has been correlated with an altered immune response in cardiovascular diseases. The spleen is the largest immune organ exerting a potent influence on the cardiovascular system during disease and is characterized by a dense noradrenergic innervation. Taken together, these aspects led to hypothesize a key role of neuroimmune mechanisms in the onset and progression of hypertension. This review discusses how the nervous and splenic immune systems interact and how the mechanisms underlying the neuroimmune cross talk influence the disease progression.

Stress in the microbiome-immune crosstalk

The gut microbiota exerts a mutualistic interaction with the host in a fragile ecosystem and the host intestinal, neural, and immune cells. Perturbations of the gastrointestinal track composition after stress have profound consequences on the central nervous system and the immune system. Reciprocally, brain signals after stress affect the gut microbiota highlighting the bidirectional communication between the brain and the gut. Here, we focus on the potential role of inflammation in mediating stress-induced gut-brain changes and discuss the impact of several immune cells and inflammatory molecules of the gut-brain dialogue after stress. Understanding the impact of microbial changes on the immune system after stress might provide new avenues for therapy.

Targeting the gut microbiota with dietary fibers: a novel approach to prevent the development cardiovascular complications linked to systemic lupus erythematosus in a preclinical study

This study is to investigate whether dietary fiber intake prevents vascular and renal damage in a genetic mouse model of systemic lupus erythematosus (SLE), and the contribution of gut microbiota in the protective effects. Female NZBWF1 (SLE) mice were treated with resistant-starch (RS) or inulin-type fructans (ITF). In addition, inoculation of fecal microbiota from these experimental groups to recipient normotensive female C57Bl/6J germ-free (GF) mice was performed. Both fiber treatments, especially RS, prevented the development of hypertension, renal injury, improved the aortic relaxation induced by acetylcholine, and the vascular oxidative stress. RS and ITF treatments increased the proportion of acetate- and butyrate-producing bacteria, respectively, improved colonic inflammation and integrity, endotoxemia, and decreased helper T (Th)17 proportion in mesenteric lymph nodes (MLNs), blood, and aorta in SLE mice. However, disease activity (splenomegaly and anti-ds-DNA) was unaffected by both fibers. T cell priming and Th17 differentiation in MLNs and increased Th17 infiltration was linked to aortic endothelial dysfunction and hypertension after inoculation of fecal microbiota from SLE mice to GF mice, without changes in proteinuria and autoimmunity. All these effects were lower in GF mice after fecal inoculation from fiber-treated SLE mice. In conclusion, these findings support that fiber consumption prevented the development of hypertension by rebalancing of dysfunctional gut-immune system-vascular wall axis in SLE.

Effects of Gut Microbiota on Hypertension and the Cardiovascular System

Cardiovascular diseases, which include hypertension and atherosclerosis, are a group of disorders that affect the heart and blood vessels [...].

Gut microbiota and microbiota-derived metabolites in cardiovascular diseases

ABSTRACT

Cardiovascular diseases, including heart failure, coronary artery disease, atherosclerosis, aneurysm, thrombosis, and hypertension, are a great economic burden and threat to human health and are the major cause of death worldwide. Recently, researchers have begun to appreciate the role of microbial ecosystems within the human body in contributing to metabolic and cardiovascular disorders. Accumulating evidence has demonstrated that the gut microbiota is closely associated with the occurrence and development of cardiovascular diseases. The gut microbiota functions as an endocrine organ that secretes bioactive metabolites that participate in the maintenance of cardiovascular homeostasis, and their dysfunction can directly influence the progression of cardiovascular disease. This review summarizes the current literature demonstrating the role of the gut microbiota in the development of cardiovascular diseases. We also highlight the mechanism by which well-documented gut microbiota-derived metabolites, especially trimethylamine N-oxide, short-chain fatty acids, and phenylacetylglutamine, promote or inhibit the pathogenesis of cardiovascular diseases. We also discuss the therapeutic potential of altering the gut microbiota and microbiota-derived metabolites to improve or prevent cardiovascular diseases.

Treatment with Ligilactobacillus murinus lowers blood pressure and intestinal permeability in spontaneously hypertensive rats

One feature of hypertension is a microbial imbalance with increased intestinal permeability. In this study, we examined whether an alteration in the microbiota affects blood pressure and intestinal permeability in spontaneously hypertensive rats (SHRs). We performed a 16S metagenome analysis of feces from 10- to 15-week-old SHRs using a synthetic long-read sequencing approach, and found a candidate for the microbiome treatment, Ligilactobacillus murinus (L. murinus), that was robustly decreased. Oral administration of L. murinus to SHRs for 2 weeks significantly inhibited blood pressure elevation and improved endothelium-dependent vasodilation but did not attenuate enhanced vascular contraction in SHR mesenteric arteries. The proximal colon of SHRs exhibited increased intestinal permeability with decreased levels of the tight junction protein claudin 4, morphological changes such as decreased intestinal crypts and elevated TNF-α levels, which was reversed by treatment with L. murinus. Consistent with these intestinal phenotypes, plasma lipopolysaccharides levels were elevated in SHR but decreased following L. murinus administration. We concluded that oral administration of L. murinus to SHRs exerts protective effects on intestinal permeability via restoration of claudin 4 expression and reversal of morphologic disorder, which may improve low-grade endotoxemia and thus reduce development of hypertension via recovery of endothelial vasodilating functions.

Unraveling mechanistic insights into the role of microbiome in neurogenic hypertension: A comprehensive review

Neurogenic hypertension, a complex and multifactorial cardiovascular disorder, is known to be influenced by various genetic, environmental, and lifestyle factors. In recent years, there has been growing interest in the role of the gut microbiome in hypertension pathogenesis. The bidirectional communication between the gut microbiota and the central nervous system, known as the microbiota-gut-brain axis, has emerged as a crucial mechanism through which the gut microbiota exerts its influence on neuroinflammation, immune responses, and blood pressure regulation. Recent studies have shown how the microbiome has a substantial impact on a variety of physiological functions, such as cardiovascular health. The increased sympathetic activity to the gut may cause microbial dysbiosis, increased permeability of the gut, and increased inflammatory reactions by altering a number of intestinal bacteria producing short-chain fatty acids (SCFAs) and the concentrations of lipopolysaccharide (LPS) in the plasma. Collectively, these microbial metabolic and structural compounds stimulate sympathetic stimulation, which may be an important stage in the onset of hypertension. The result is an upsurge in peripheral and central inflammatory response. In addition, it has recently been shown that a link between the immune system and the gut microbiota might play a significant role in hypertension. The therapeutic implications of the gut microbiome including probiotic usage, prebiotics, dietary modifications, and fecal microbiota transplantation in neurogenic hypertension have also been found. A large body of research suggests that probiotic supplementation might help reduce chronic inflammation and hypertension that have an association with dysbiosis in the gut microbiota. Overall, this review sheds light on the intricate interplay between the gut microbiome and neurogenic hypertension, providing valuable insights for both researchers and clinicians. As our knowledge of the microbiome's role in hypertension expands, novel therapeutic strategies and diagnostic biomarkers may pave the way for more effective management and prevention of this prevalent cardiovascular disorder. Exploring the potential of the microbiome in hypertension offers an exciting avenue for future research and offers opportunities for precision medicine and improved patient care.

The role of gut microbiota and drug interactions in the development of colorectal cancer

The human gut microbiota is a complex ecosystem regulating the host's environmental interaction. The same functional food or drug may have varying bioavailability and distinct effects on different individuals. Drugs such as antibiotics can alter the intestinal flora, thus affecting health. However, the relationship between intestinal flora and non-antibiotic drugs is bidirectional: it is not only affected by drugs; nevertheless, it can alter the drug structure through enzymes and change the bioavailability, biological activity, or toxicity of drugs to improve their efficacy and safety. This review summarizes the roles and mechanisms of antibiotics, antihypertensive drugs, nonsteroidal anti-inflammatory drugs, lipid-lowering drugs, hypoglycemic drugs, virus-associated therapies, metabolites, and dietary in modulating the colorectal cancer gut microbiota. It provides a reference for future antitumor therapy targeting intestinal microorganisms.

Emodin Inhibited Pathological Cardiac Hypertrophy in Response to Angiotensin-Induced Hypertension and Altered the Gut Microbiome

OBJECTIVE

Evidence suggests that food bioactives affect the epigenome to prevent pathological cardiac hypertrophy. Recently, we showed that emodin, an anthraquinone, attenuated pathological cardiac hypertrophy and histone deacetylase (HDAC) activity. However, we only examined the cardioprotective effects of emodin's parent compound and not those of emodin metabolites or of emodin-gut microbiome interactions. The microbiome has emerged as a key player in chronic diseases such as metabolic and cardiac disease. Thus, we hypothesized that emodin could reverse hypertension-induced changes in microbial communities.

METHODS

Normo- and hypertensive (angiotensin II) C57/BL6 female mice were randomly assigned to receive a vehicle (Veh; DMSO:PEG 1:1) or emodin (Emod; 30 mg/kg) for 14 days. Body weights were collected pre- and post-treatment, and blood pressure was assessed via tail cuff. At the study's end, the mice were euthanized and assessed for their heart weights. In addition, stool samples and cecal contents were collected to elucidate changes in the microbial populations using 16S rRNA sequencing. Lastly, the tissue was lysed, and RNA was isolated for qPCR. One-way ANOVA with Tukey's post hoc test was performed unless otherwise specified, and p < 0.05 was considered significant.

RESULTS

Emodin significantly attenuated cardiac hypertrophy in the female mice. No significant changes were observed in body weight or systolic blood pressure in response to hypertension or emodin. Lastly, analysis suggests that hypertension altered the microbiome in the cecum and cecal content, with additional evidence to support that emodin affects gut microbiota in the feces and colon.

CONCLUSIONS

Our data demonstrate that emodin attenuates pathological hypertrophy in female mice. Future research is needed to dissect if changes in the microbiome contributes to emodin-mediated attenuation in cardiac remodeling.

Host-Microbiome Interactions: Tryptophan Metabolism and Aromatic Hydrocarbon Receptors after Traumatic Brain Injury

Traumatic brain injury refers to the damage caused to intracranial tissues by an external force acting on the head, leading to both immediate and prolonged harmful effects. Neuroinflammatory responses play a critical role in exacerbating the primary injury during the acute and chronic phases of TBI. Research has demonstrated that numerous neuroinflammatory responses are mediated through the "microbiota-gut-brain axis," which signifies the functional connection between the gut microbiota and the brain. The aryl hydrocarbon receptor (AhR) plays a vital role in facilitating communication between the host and microbiota through recognizing specific ligands produced directly or indirectly by the microbiota. Tryptophan (trp), an indispensable amino acid in animals and humans, represents one of the key endogenous ligands for AhR. The metabolites of trp have significant effects on the functioning of the central nervous system (CNS) through activating AHR signalling, thereby establishing bidirectional communication between the gut microbiota and the brain. These interactions are mediated through immune, metabolic, and neural signalling mechanisms. In this review, we emphasize the co-metabolism of tryptophan in the gut microbiota and the signalling pathway mediated by AHR following TBI. Furthermore, we discuss the impact of these mechanisms on the underlying processes involved in traumatic brain injury, while also addressing potential future targets for intervention.

The interplay between microbial metabolites and macrophages in cardiovascular diseases: A comprehensive review

The gut microbiome has emerged as a crucial player in developing and progressing cardiovascular diseases (CVDs). Recent studies have highlighted the role of microbial metabolites in modulating immune cell function and their impact on CVD. Macrophages, which have a significant function in the pathogenesis of CVD, are very vulnerable to the effects of microbial metabolites. Microbial metabolites, such as short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), have been linked to atherosclerosis and the regulation of immune functions. Butyrate has been demonstrated to reduce monocyte migration and inhibit monocyte attachment to injured endothelial cells, potentially contributing to the attenuation of the inflammatory response and the progression of atherosclerosis. On the other hand, TMAO, another compound generated by gut bacteria, has been linked to atherosclerosis due to its impact on lipid metabolism and the accumulation of cholesterol in macrophages. Indole-3-propionic acid, a tryptophan metabolite produced solely by microbes, has been found to promote the development of atherosclerosis by stimulating macrophage reverse cholesterol transport (RCT) and raising the expression of ABCA1. This review comprehensively discusses how various microbiota-produced metabolites affect macrophage polarization, inflammation, and foam cell formation in CVD. We also highlight the mechanisms underlying these effects and the potential therapeutic applications of targeting microbial metabolites in treating CVD.

Impact of the gut microbiota on angiotensin Ⅱ-related disorders and its mechanisms

The renin-angiotensin system (RAS) consists of multiple angiotensin peptides and performs various biological functions mediated by distinct receptors. Angiotensin II (Ang II) is the major effector of the RAS and affects the occurrence and development of inflammation, diabetes mellitus and its complications, hypertension, and end-organ damage via the Ang II type 1 receptor. Recently, considerable interest has been given to the association and interaction between the gut microbiota and host. Increasing evidence suggests that the gut microbiota may contribute to cardiovascular diseases, obesity, type 2 diabetes mellitus, chronic inflammatory diseases, and chronic kidney disease. Recent data have confirmed that Ang II can induce an imbalance in the intestinal flora and further aggravate disease progression. Furthermore, angiotensin converting enzyme 2 is another player in RAS, alleviates the deleterious effects of Ang II, modulates gut microbial dysbiosis, local and systemic immune responses associated with coronavirus disease 19. Due to the complicated etiology of pathologies, the precise mechanisms that link disease processes with specific characteristics of the gut microbiota remain obscure. This review aims to highlight the complex interactions between the gut microbiota and its metabolites in Ang II-related disease progression, and summarize the possible mechanisms. Deciphering these mechanisms will provide a theoretical basis for novel therapeutic strategies for disease prevention and treatment. Finally, we discuss therapies targeting the gut microbiota to treat Ang II-related disorders.

Gut Microbiota and Cardiovascular Disease: Evidence on the Metabolic and Inflammatory Background of a Complex Relationship

Several studies in recent years have demonstrated that gut microbiota-host interactions play an important role in human health and disease, including inflammatory and cardiovascular diseases. Dysbiosis has been linked to not only well-known inflammatory diseases, such as inflammatory bowel diseases, rheumatoid arthritis, and systemic lupus erythematous, but also to cardiovascular risk factors, such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus. The ways the microbiota is involved in modulating cardiovascular risk are multiple and not only related to inflammatory mechanisms. Indeed, human and the gut microbiome cooperate as a metabolically active superorganism, and this affects host physiology through metabolic pathways. In turn, congestion of the splanchnic circulation associated with heart failure, edema of the intestinal wall, and altered function and permeability of the intestinal barrier result in the translocation of bacteria and their products into the systemic circulation, further enhancing the pro-inflammatory conditions underlying cardiovascular disorders. The aim of the present review is to describe the complex interplay between gut microbiota, its metabolites, and the development and evolution of cardiovascular diseases. We also discuss the possible interventions intended to modulate the gut microbiota to reduce cardiovascular risk.

Review on the protective mechanism of astragaloside IV against cardiovascular diseases

Cardiovascular disease is a global health problem. Astragaloside IV (AS-IV) is a saponin compound extracted from the roots of the Chinese herb Astragalus. Over the past few decades, AS-IV has been shown to possess various pharmacological properties. It can protect the myocardium through antioxidative stress, anti-inflammatory effects, regulation of calcium homeostasis, improvement of myocardial energy metabolism, anti-apoptosis, anti-cardiomyocyte hypertrophy, anti-myocardial fibrosis, regulation of myocardial autophagy, and improvement of myocardial microcirculation. AS-IV exerts protective effects on blood vessels. For example, it can protect vascular endothelial cells through antioxidative stress and anti-inflammatory pathways, relax blood vessels, stabilize atherosclerotic plaques, and inhibit the proliferation and migration of vascular smooth muscle cells. Thus, the bioavailability of AS-IV is low. Toxicology indicates that AS-IV is safe, but should be used cautiously in pregnant women. In this paper, we review the mechanisms of AS-IV prevention and treatment of cardiovascular diseases in recent years to provide a reference for future research and drug development.

The role of dietary salt in metabolism and energy balance: Insights beyond cardiovascular disease

Dietary salt (NaCl) is essential to an organism's survival. However, today's diets are dominated by excessive salt intake, which significantly impacts individual and population health. High salt intake is closely linked to cardiovascular disease (CVD), especially hypertension, through a number of well-studied mechanisms. Emerging evidence indicates that salt overconsumption may also be associated with metabolic disorders. In this review, we first summarize recent updates on the mechanisms of salt-induced CVD, the effects of salt reduction and the use of salt substitution as a therapy. Next, we focus on how high salt intake can impact metabolism and energy balance, describing the mechanisms through which this occurs, including leptin resistance, the overproduction of fructose and ghrelin, insulin resistance and altered hormonal factors. A further influence on metabolism worth noting is the reported role of salt in inducing thermogenesis and increasing body temperature, leading to an increase in energy expenditure. While this result could be viewed as a positive metabolic effect because it promotes a negative energy balance to combat obesity, caution must be taken with this frame of thinking given the deleterious consequences of chronic high salt intake on cardiovascular health. Nevertheless, this review highlights the importance of salt as a noncaloric nutrient in regulating whole-body energy homeostasis. Through this review, we hope to provide a scientific framework for future studies to systematically address the metabolic impacts of dietary salt and salt replacement treatments. In addition, we hope to form a foundation for future clinical trials to explore how these salt-induced metabolic changes impact obesity development and progression, and to elucidate the regulatory mechanisms that drive these changes, with the aim of developing novel therapeutics for obesity and CVD.

Impact of Gut Microbiota on the Peripheral Nervous System in Physiological, Regenerative and Pathological Conditions

It has been widely demonstrated that the gut microbiota is responsible for essential functions in human health and that its perturbation is implicated in the development and progression of a growing list of diseases. The number of studies evaluating how the gut microbiota interacts with and influences other organs and systems in the body and vice versa is constantly increasing and several 'gut-organ axes' have already been defined. Recently, the view on the link between the gut microbiota (GM) and the peripheral nervous system (PNS) has become broader by exceeding the fact that the PNS can serve as a systemic carrier of GM-derived metabolites and products to other organs. The PNS as the communication network between the central nervous system and the periphery of the body and internal organs can rather be affected itself by GM perturbation. In this review, we summarize the current knowledge about the impact of gut microbiota on the PNS, with regard to its somatic and autonomic divisions, in physiological, regenerative and pathological conditions.

Gut Microbiota-Derived Trimethylamine N-Oxide Contributes to Abdominal Aortic Aneurysm Through Inflammatory and Apoptotic Mechanisms

BACKGROUND

Large-scale human and mechanistic mouse studies indicate a strong relationship between the microbiome-dependent metabolite trimethylamine N-oxide (TMAO) and several cardiometabolic diseases. This study aims to investigate the role of TMAO in the pathogenesis of abdominal aortic aneurysm (AAA) and target its parent microbes as a potential pharmacological intervention.

METHODS

TMAO and choline metabolites were examined in plasma samples, with associated clinical data, from 2 independent patient cohorts (N=2129 total). Mice were fed a high-choline diet and underwent 2 murine AAA models, angiotensin II infusion in low-density lipoprotein receptor-deficient (Ldlr-/-) mice or topical porcine pancreatic elastase in C57BL/6J mice. Gut microbial production of TMAO was inhibited through broad-spectrum antibiotics, targeted inhibition of the gut microbial choline TMA lyase (CutC/D) with fluoromethylcholine, or the use of mice genetically deficient in flavin monooxygenase 3 (Fmo3-/-). Finally, RNA sequencing of in vitro human vascular smooth muscle cells and in vivo mouse aortas was used to investigate how TMAO affects AAA.

RESULTS

Elevated TMAO was associated with increased AAA incidence and growth in both patient cohorts studied. Dietary choline supplementation augmented plasma TMAO and aortic diameter in both mouse models of AAA, which was suppressed with poorly absorbed oral broad-spectrum antibiotics. Treatment with fluoromethylcholine ablated TMAO production, attenuated choline-augmented aneurysm initiation, and halted progression of an established aneurysm model. In addition, Fmo3-/- mice had reduced plasma TMAO and aortic diameters and were protected from AAA rupture compared with wild-type mice. RNA sequencing and functional analyses revealed choline supplementation in mice or TMAO treatment of human vascular smooth muscle cells-augmented gene pathways associated with the endoplasmic reticulum stress response, specifically the endoplasmic reticulum stress kinase PERK.

CONCLUSIONS

These results define a role for gut microbiota-generated TMAO in AAA formation through upregulation of endoplasmic reticulum stress-related pathways in the aortic wall. In addition, inhibition of microbiome-derived TMAO may serve as a novel therapeutic approach for AAA treatment where none currently exist.

Pivotal Role of Intestinal Microbiota and Intraluminal Metabolites for the Maintenance of Gut-Bone Physiology

Intestinal microbiota, and their mutual interactions with host tissues, are pivotal for the maintenance of organ physiology. Indeed, intraluminal signals influence adjacent and even distal tissues. Consequently, disruptions in the composition or functions of microbiota and subsequent altered host-microbiota interactions disturb the homeostasis of multiple organ systems, including the bone. Thus, gut microbiota can influence bone mass and physiology, as well as postnatal skeletal evolution. Alterations in nutrient or electrolyte absorption, metabolism, or immune functions, due to the translocation of microbial antigens or metabolites across intestinal barriers, affect bone tissues, as well. Intestinal microbiota can directly and indirectly alter bone density and bone remodeling. Intestinal dysbiosis and a subsequently disturbed gut-bone axis are characteristic for patients with inflammatory bowel disease (IBD) who suffer from various intestinal symptoms and multiple bone-related complications, such as arthritis or osteoporosis. Immune cells affecting the joints are presumably even primed in the gut. Furthermore, intestinal dysbiosis impairs hormone metabolism and electrolyte balance. On the other hand, less is known about the impact of bone metabolism on gut physiology. In this review, we summarized current knowledge of gut microbiota, metabolites and microbiota-primed immune cells in IBD and bone-related complications.

Nutritional implications in the mechanistic link between the intestinal microbiome, renin-angiotensin system, and the development of obesity and metabolic syndrome

Obesity and metabolic disorders represent a significant global health problem and the gut microbiota plays an important role in modulating systemic homeostasis. Recent evidence shows that microbiota and its signaling pathways may affect the whole metabolism and the Renin-Angiotensin System (RAS), which in turn seems to modify microbiota. The present review aimed to investigate nutritional implications in the mechanistic link between the intestinal microbiome, renin-angiotensin system, and the development of obesity and metabolic syndrome components. A description of metabolic changes was obtained based on relevant scientific literature. The molecular and physiological mechanisms that impact the human microbiome were addressed, including the gut microbiota associated with obesity, diabetes, and hepatic steatosis. The RAS interaction signaling and modulation were analyzed. Strategies including the use of prebiotics, symbiotics, probiotics, and biotechnology may affect the gut microbiota and its impact on human health.

The gut microbiome and hypertension

A large body of evidence has emerged in the past decade supporting a role for the gut microbiome in the regulation of blood pressure. The field has moved from association to causation in the last 5 years, with studies that have used germ-free animals, antibiotic treatments and direct supplementation with microbial metabolites. The gut microbiome can regulate blood pressure through several mechanisms, including through gut dysbiosis-induced changes in microbiome-associated gene pathways in the host. Microbiota-derived metabolites are either beneficial (for example, short-chain fatty acids and indole-3-lactic acid) or detrimental (for example, trimethylamine N-oxide), and can activate several downstream signalling pathways via G protein-coupled receptors or through direct immune cell activation. Moreover, dysbiosis-associated breakdown of the gut epithelial barrier can elicit systemic inflammation and disrupt intestinal mechanotransduction. These alterations activate mechanisms that are traditionally associated with blood pressure regulation, such as the renin-angiotensin-aldosterone system, the autonomic nervous system, and the immune system. Several methodological and technological challenges remain in gut microbiome research, and the solutions involve minimizing confounding factors, establishing causality and acting globally to improve sample diversity. New clinical trials, precision microbiome medicine and computational methods such as Mendelian randomization have the potential to enable leveraging of the microbiome for translational applications to lower blood pressure.

Higher Plasma Levels of Valerate Produced by Gut Microbiota May Have a Beneficial Impact on Renal Function

OBJECTIVE

Observational studies have evaluated the relationships among plasma short chain fatty acids (SCFA) produced by gut microbiota, renal function, and risk of chronic kidney disease (CKD). In the present study, Mendelian Randomization (MR) analysis was applied to obtain unconfounded estimates of the casual association of genetically determined plasma valerate (an SCFA) with kidney function and risk of CKD.

METHOD

MR was performed by using summary-level data from the largest genome-wide association studies (GWAS) conducted on plasma valerate, CKD, and estimated glomerular filtration rate (eGFR; separately in diabetic and nondiabetic individuals). Inverse variance weighted method (IVW), weighted median-based method, MR-Egger, as well as MR-Pleiotropy RESidual Sum and Outlier (PRESSO) were applied. Sensitivity analysis was conducted using the leave-one-out method.

RESULTS

No significant association was observed between plasma valerate and CKD (IVW: β = 0.234, p = 0.744). In contrast, plasma valerate was positively associated with eGFR in the total population (IVW: β = 0.049, p = 0.022) and among nondiabetic individuals (IVW: β = 0.058, p = 0.009), but not in the diabetic population (IVW: β = -0.052, p = 0.603). None of the estimated associations was subjected to significant level of heterogeneity. Furthermore, MR-PRESSO analysis did not show any chance of outlier for all estimates. The pleiotropy test, with very a negligible intercept and insignificant p value, also indicated no chance of pleiotropy for all of our estimations (all p > 0.539). The results of the MR-Robust Adjusted Profile Score were identical with the IVW estimates, highlighting again no possibility of pleiotropy. Results of the leave-one-out method demonstrated that the links were not driven by single-nucleotide polymorphisms.

CONCLUSIONS

Individuals with higher plasma valerate levels had better renal function, defined by eGFR. This finding was observed in the total population and in nondiabetic subjects, but not in those with diabetes. Further research is needed to elucidate the links among plasma valerate, kidney function, and CKD.

Immune communication between the intestinal microbiota and the cardiovascular system

The intestine hosts a large number of microbial communities. Recent studies have shown that gut microbiota-mediated immune responses play a vital role in developing cardiovascular diseases (CVD). Immune cells are extensively infiltrated in the gut and heart tissues, such as T cells, B cells, and macrophages. They play a crucial role in the crosstalk between the heart and gut microbiota. And the microbiota influences the bidirectional function of immune cells in CVD such as myocardial infarction and atherosclerosis, including through metabolites. The mapping of immune cell-mediated immune networks in the heart and gut provides us with new targets for treating CVD. This review discusses the role of immune cells in gut microbiota and cardiac communication during health and CVD.

Fecal Microbiota Transplantation in Reducing Uremic Toxins Accumulation in Kidney Disease: Current Understanding and Future Perspectives

During the past decades, the gut microbiome emerged as a key player in kidney disease. Dysbiosis-related uremic toxins together with pro-inflammatory mediators are the main factors in a deteriorating kidney function. The toxicity of uremic compounds has been well-documented in a plethora of pathophysiological mechanisms in kidney disease, such as cardiovascular injury (CVI), metabolic dysfunction, and inflammation. Accumulating data on the detrimental effect of uremic solutes in kidney disease supported the development of many strategies to restore eubiosis. Fecal microbiota transplantation (FMT) spread as an encouraging treatment for different dysbiosis-associated disorders. In this scenario, flourishing studies indicate that fecal transplantation could represent a novel treatment to reduce the uremic toxins accumulation. Here, we present the state-of-the-art concerning the application of FMT on kidney disease to restore eubiosis and reverse the retention of uremic toxins.

Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy

Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.

Endotoxemia and Gastrointestinal Cancers: Insight into the Mechanisms Underlying a Dangerous Relationship

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the membrane of gram-negative bacteria and a well-recognized marker of sepsis. In case of disruption of the intestinal barrier, as occurs with unhealthy diets, alcohol consumption, or during chronic diseases, the microbiota residing in the gastrointestinal tract becomes a crucial factor in amplifying the systemic inflammatory response. Indeed, the translocation of LPS into the bloodstream and its interaction with toll-like receptors (TLRs) triggers molecular pathways involved in cytokine release and immune dysregulation. This is a critical step in the exacerbation of many diseases, including metabolic disorders and cancer. Indeed, the role of LPS in cancer development is widely recognized, and examples include gastric tumor related to Helicobacter pylori infection and hepatocellular carcinoma, both of which are preceded by a prolonged inflammatory injury; in addition, the risk of recurrence and development of metastasis appears to be associated with endotoxemia. Here, we review the mechanisms that link the promotion and progression of tumorigenesis with endotoxemia, and the possible therapeutic interventions that can be deployed to counteract these events.

Gut microbiota and its metabolites - molecular mechanisms and management strategies in diabetic kidney disease

Diabetic kidney disease (DKD) is one of the major microvascular complications of diabetes mellitus and is also one of the serious risk factors in cardiovascular events, end-stage renal disease, and mortality. DKD is associated with the diversified, compositional, and functional alterations of gut microbiota. The interaction between gut microbiota and host is mainly achieved through metabolites, which are small molecules produced by microbial metabolism from exogenous dietary substrates and endogenous host compounds. The gut microbiota plays a critical role in the pathogenesis of DKD by producing multitudinous metabolites. Nevertheless, detailed mechanisms of gut microbiota and its metabolites involved in the occurrence and development of DKD have not been completely elucidated. This review summarizes the specific classes of gut microbiota-derived metabolites, aims to explore the molecular mechanisms of gut microbiota in DKD pathophysiology and progression, recognizes biomarkers for the screening, diagnosis, and prognosis of DKD, as well as provides novel therapeutic strategies for DKD.

Clostridium butyricum and Bifidobacterium pseudolongum Attenuate the Development of Cardiac Fibrosis in Mice

Cardiac fibrosis is an integral aspect of every form of cardiovascular diseases, which is one of the leading causes of death worldwide. It is urgent to explore new effective drugs and treatments. In this paper, transverse aortic constriction (TAC)-induced cardiac fibrosis was significantly alleviated by a cocktail of antibiotics to clear the intestinal flora, indicating that the gut microbiota was associated with the disease process of cardiac fibrosis. We transplanted feces from sham-operated and TAC-treated mice to mice treated with a cocktail of antibiotics. We found that TAC-treated gut microbiota dysbiosis cannot cause cardiac fibrosis on its own. Interestingly, healthy fecal microbiota transplantation could alleviate cardiac fibrosis, indicating that targeted probiotics and related metabolite intervention may restore a normal microenvironment for the treatment or prevention of cardiac fibrosis. We used 16S rRNA sequencing of fecal samples and discovered that butyric acid-producing bacteria and Bifidobacterium pseudolongum were the dominant bacteria in the group with the lowest degree of cardiac fibrosis. Moreover, we demonstrated that sodium butyrate prevented the development of cardiac fibrosis. The effect of Clostridium butyricum (butyric acid-producing bacteria) was better than that of B. pseudolongum on cardiac fibrosis. Surprisingly, the cocktail of two probiotics had a stronger ability than a single probiotic. In conclusion, therapies targeting the gut microbiota and metabolites such as probiotics present new strategies for treating cardiovascular disease. IMPORTANCE Cardiac fibrosis is a basic process in cardiac remodeling. It is related to almost all types of cardiovascular diseases (CVD) and has become an important global health problem. Basic research and a number of clinical studies have shown that myocardial fibrosis can be prevented and reversed to a certain extent. It is urgent to explore new effective drugs and treatments. We indicated a causal relationship between cardiac fibrosis and gut microbiota. Gut microbiota dysbiosis cannot cause cardiac fibrosis on its own. Interestingly, healthy fecal microbiota transplantation could alleviate cardiac fibrosis. According to our findings, the combined use of butyric acid-producing bacteria and B. pseudolongum can help prevent cardiac fibrosis. Therapies targeting the gut microbiota and metabolites, such as probiotics, represent new strategies for treating cardiovascular disease.

Immune mechanism of gut microbiota and its metabolites in the occurrence and development of cardiovascular diseases

The risk of cardiovascular disease (CVD) is associated with unusual changes in the human gut microbiota, most commonly coronary atherosclerotic heart disease, hypertension, and heart failure. Immune mechanisms maintain a dynamic balance between the gut microbiota and the host immune system. When one side changes and the balance is disrupted, different degrees of damage are inflicted on the host and a diseased state gradually develops over time. This review summarizes the immune mechanism of the gut microbiota and its metabolites in the occurrence of common CVDs, discusses the relationship between gut-heart axis dysfunction and the progression of CVD, and lists the currently effective methods of regulating the gut microbiota for the treatment of CVDs.

The central role of the gut in intensive care

Critically ill patients undergo early impairment of their gut microbiota (GM) due to routine antibiotic therapies and other environmental factors leading to intestinal dysbiosis. The GM establishes connections with the rest of the human body along several axes representing critical inter-organ crosstalks that, once disrupted, play a major role in the pathophysiology of numerous diseases and their complications. Key players in this communication are GM metabolites such as short-chain fatty acids and bile acids, neurotransmitters, hormones, interleukins, and toxins. Intensivists juggle at the crossroad of multiple connections between the intestine and the rest of the body. Harnessing the GM in ICU could improve the management of several challenges, such as infections, traumatic brain injury, heart failure, kidney injury, and liver dysfunction. The study of molecular pathways affected by the GM in different clinical conditions is still at an early stage, and evidence in critically ill patients is lacking. This review aims to describe dysbiosis in critical illness and provide intensivists with a perspective on the potential as adjuvant strategies (e.g., nutrition, probiotics, prebiotics and synbiotics supplementation, adsorbent charcoal, beta-lactamase, and fecal microbiota transplantation) to modulate the GM in ICU patients and attempt to restore eubiosis.

Gallic acid ameliorates atherosclerosis and vascular senescence and remodels the microbiome in a sex-dependent manner in ApoE(-/-) mice

Polyphenols found in fruits and vegetables are associated with a reduced incidence of cardiovascular disease (CVD), the leading cause of death in the USA. Our lab demonstrated that blackberry supplementation reduces atherosclerosis in male, but not in female mice. The current study investigates whether gallic acid (GA), a polyphenol abundant in blackberry, decreases plaque and whether its effect is also sex-dependent. In vitro work using vascular smooth muscle cells (VSMCs) demonstrated that GA reduced cell signaling associated with proliferation, migration, and senescence. ApoE^-/- male and female mice were treated with and without 0.2% GA in drinking water and fed a chow diet (2 weeks), then switched to high-fat diet (HFD) (5 weeks) with the same GA regimen. Similar to the blackberry study, GA reduced atherosclerosis only in males. This GA-induced plaque reduction was independent of plasma cholesterol, triglycerides (TG), LDL, or HDL but corresponded with indices of lower inflammation. Males showed reduced spleen weight and serum IL3 and IL12 levels, and gut health improvement. In females, GA increased anti-atherogenic (HDL and IL10) molecules, while upregulating several pro-inflammatory cytokines and chemokines, including tumor necrosis factor α (TNFα). A major sex-dependent effect of GA was the almost complete disappearance of Eubacterium fissicatena and Turicibacter induced by HFD in males, a finding not seen in females. This study provides novel insights into how GA can improve gut microbiota alterations associated with CVD and suggests that males suffering from atherosclerosis may benefit from GA supplementation, as this polyphenol partially restored microbiome dysbiosis.

Microbiota in a long survival discourse with the human host

The relationship between human health and gut microbiota is becoming more apparent. It is now widely believed that healthy gut flora plays a vital role in the overall well-being of the individual. There are spatial and temporal variations in the distribution of microbes from the esophagus to the rectum throughout an individual's lifetime. Through the development of genome sequencing technologies, scientists have been able to study the interactions between different microorganisms and their hosts to improve the health and disease of individuals. The normal gut microbiota provides various functions to the host, whereas the host, in turn, provides nutrients and promotes the development of healthy and resilient microbiota communities. Thus, the microbiota provides and maintains the gut's structural integrity and protects the gut against pathogens. The development of the normal gut microbiota is influenced by various factors. Some of these include the mode of delivery, diet, and antibiotics. In addition, the environment can also affect the development of the gut microbiota. For example, one of the main concerns of antibiotic use is the alteration of the gut microbiota, which could lead to the development of multidrug-resistant organisms. When microbes are disturbed, it can potentially lead to various diseases. Depending on the species' ability to adapt to the human body's environment, the fate of the microbes in the host and their relationship with the human body are decided. This review aims to provide a comprehensive analysis of microbe, microbes-host immune interactions, and factors that can disturb their interactions.

Kidney microbiota dysbiosis contributes to the development of hypertension

Gut microbiota dysbiosis promotes metabolic syndromes (e.g., hypertension); however, the patterns that drive hypertensive pathology and could be targeted for therapeutic intervention are unclear. We hypothesized that gut microbes might translocate to the kidney to trigger hypertension. We aimed to uncover their method of colonization, and thereby how to maintain blood pressure homeostasis. Using combined approaches based on fluorescence in situ hybridization (FISH) and immunofluorescence staining, electron microscopy analysis, bacterial cultures, species identification, and RNA-sequencing-based meta-transcriptomics, we first demonstrated the presence of bacteria within the kidney of spontaneously hypertensive rats (SHRs) and its normotensive counterpart, Wistar-Kyoto rats (WKYs), and patients with hypertension. Translocated renal bacteria were coated with secretory IgA (sIgA) or remained dormant in the L-form. Klebsiella pneumoniae (K.pn) was identified in the kidneys of germ-free (GF) mice following intestinal transplantation, which suggested an influx of gut bacteria into the kidneys. Renal bacterial taxa and their function are associated with hypertension. Hypertensive hosts showed increased richness in the pathobionts of their kidneys, which were partly derived from the gastrointestinal tract. We also demonstrated the indispensable role of bacterial IgA proteases in the translocation of live microbes. Furthermore, Tartary buckwheat dietary intervention reduced blood pressure and modulated the core renal flora-host ecosystem to near-normal states. Taken together, the unique patterns of viable and dormant bacteria in the kidney provide insight into the pathogenesis of non-communicable chronic diseases and cardiometabolic diseases (e.g., hypertension), and may lead to potential novel microbiota-targeted dietary therapies.

Intestinal microbiota: A promising therapeutic target for hypertension

Hypertension has developed into an escalating serious global public health problem with multiple and unclear pathophysiological mechanisms. Recent studies have identified intestinal microbiota as a key perpetrator of hypertension through a variety of mechanisms. In this review, we highlight the potential roles of the intestinal microbiota and its metabolites in the development of hypertension, as well as the therapeutic potential for targeting intestinal microbiomes. We also shed light on the main limitations and challenges of the current research and suggest directions for future investigations. Finally, we discuss the development of accurate and personalized preventive and therapeutic strategies for hypotension by the modulation of intestinal microbes and metabolites.

The modulation of gut microbiota by herbal medicine to alleviate diabetic kidney disease - A review

The treatment of diabetic kidney disease (DKD) has been the key concern of the medical community. Herbal medicine has been reported to alleviate intestinal dysbiosis, promote the excretion of toxic metabolites, and reduce the secretion of uremic toxins. However, the current understanding of the modulation of the gut microbiota by herbal medicine to delay the progression of DKD is still insufficient. Consequently, we reviewed the knowledge based on peer-reviewed English-language journals regarding regulating gut microbiota by herbal medicines in DKD. It was found that herbal medicine or their natural extracts may have the following effects: modulating the composition of intestinal flora, particularly Akkermansia, Lactobacillus, and Bacteroidetes, as well as adjusting the F/B ratio; increasing the production of SCFAs and restoring the intestinal barrier; reducing the concentration of uremic toxins (p-cresol sulfate, indole sulfate, TMAO); inhibiting inflammation and oxidative stress.

Fecal Microbiota Transplantation May Represent a Good Approach for Patients with Focal Segmental Glomerulosclerosis: A Brief Report

This is the first report of fecal microbiota transplantation (FMT) in patients with chronic kidney disease. The patient was subjected to focal segmental glomerulosclerosis (FSGS), with onset in April 2021. The main manifestation featured abnormal renal function and no proteinuria at the level of nephrotic syndrome. In May 2021, she showed biopsy-proven FSGS and was treated with glucocorticoid. However, after glucocorticoid reduction, the patient's serum creatinine increased again, so she adjusted the dosage and continued use until now. In April 2022, the patient was prescribed the FMT capsules. After FMT, the renal function remained stable, urinary protein decreased, reaching the clinical standard of complete remission, and there was no recurrence after glucocorticoid reduction. Furthermore, the patient showed significantly decreased hyperlipidemia, triglyceride (TG) and cholesterol (CHO) after FMT. During FMT, the level of cytokines fluctuated slightly, but returned to the pre-transplantation level after three months. From this, we conclude that FMT is a potential adjuvant therapy for FSGS, and patients can benefit from improving renal function and dyslipidemia.

Update on gut microbiota in cardiovascular diseases

In recent years, due to the development and widespread utilization of metagenomic sequencing and metabolomics, the relationship between gut microbiota and human cardiovascular diseases (CVDs) has received extensive attention. A growing number of studies have shown a strong relationship between gut microbiota and CVDs, such as coronary atherosclerosis, hypertension (HTN) and heart failure (HF). It has also been revealed that intestinal flora-related metabolites, such as trimethylamine-N-oxide (TMAO), short-chain fatty acids (SCFA) and bile acids (BAs), are also related to the development, prevention, treatment and prognosis of CVDs. In this review, we presented and summarized the recent findings on the relationship between gut microbiota and CVDs, and concluded several currently known gut microbiota-related metabolites and the occurrence and development of CVDs.

The Association between Gut Microbiome and Pregnancy-Induced Hypertension: A Nested Case–Control Study

(1) Background: Pregnancy-induced hypertension (PIH) is associated with obvious microbiota dysbiosis in the third trimester of pregnancy. However, the mechanisms behind these changes remain unknown. Therefore, this study aimed to explore the relationship between the gut microbiome in early pregnancy and PIH occurrence. (2) Methods: A nested case–control study design was used based on the follow-up cohort. Thirty-five PIH patients and thirty-five matched healthy pregnant women were selected as controls. The gut microbiome profiles were assessed in the first trimester using metagenomic sequencing. (3) Results: Diversity analyses showed that microbiota diversity was altered in early pregnancy. At the species level, eight bacterial species were enriched in healthy controls: Alistipes putredinis, Bacteroides vulgatus, Ruminococcus torques, Oscillibacter unclassified, Akkermansia muciniphila, Clostridium citroniae, Parasutterella excrementihominis and Burkholderiales bacterium_1_1_47. Conversely, Eubacterium rectale, and Ruminococcus bromii were enriched in PIH patients. The results of functional analysis showed that the changes in these different microorganisms may affect the blood pressure of pregnant women by affecting the metabolism of vitamin K₂, sphingolipid, lipid acid and glycine. (4) Conclusion: Microbiota dysbiosis in PIH patients begins in the first trimester of pregnancy, and this may be associated with the occurrence of PIH. Bacterial pathway analyses suggest that the gut microbiome might lead to the development of PIH through the alterations of function modules.

Advances in pathogenesis and treatment of essential hypertension

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases and the leading cause of premature death worldwide. However, the pathogenesis of the hypertension, especially essential hypertension, is complex and requires in-depth studies. Recently, new findings about essential hypertension have emerged, and these may provide important theoretical bases and therapeutic tools to break through the existing bottleneck of essential hypertension. In this review, we demonstrated important advances in the different pathogenesis areas of essential hypertension, and highlighted new treatments proposed in these areas, hoping to provide insight for the prevention and treatment of the essential hypertension.

The role of the gut microbiota in health and cardiovascular diseases

The gut microbiota is critical to human health, such as digesting nutrients, forming the intestinal epithelial barrier, regulating immune function, producing vitamins and hormones, and producing metabolites to interact with the host. Meanwhile, increasing evidence indicates that the gut microbiota has a strong correlation with the occurrence, progression and treatment of cardiovascular diseases (CVDs). In patients with CVDs and corresponding risk factors, the composition and ratio of gut microbiota have significant differences compared with their healthy counterparts. Therefore, gut microbiota dysbiosis, gut microbiota-generated metabolites, and the related signaling pathway may serve as explanations for some of the mechanisms about the occurrence and development of CVDs. Several studies have also demonstrated that many traditional and latest therapeutic treatments of CVDs are associated with the gut microbiota and its generated metabolites and related signaling pathways. Given that information, we summarized the latest advances in the current research regarding the effect of gut microbiota on health, the main cardiovascular risk factors, and CVDs, highlighted the roles and mechanisms of several metabolites, and introduced corresponding promising treatments for CVDs regarding the gut microbiota. Therefore, this review mainly focuses on exploring the role of gut microbiota related metabolites and their therapeutic potential in CVDs, which may eventually provide better solutions in the development of therapeutic treatment as well as the prevention of CVDs.

Crosstalk between the Gut and Brain in Ischemic Stroke: Mechanistic Insights and Therapeutic Options

There has been a significant amount of interest in the past two decades in the study of the evolution of the gut microbiota, its internal and external impacts on the gut, and risk factors for cerebrovascular disorders such as cerebral ischemic stroke. The network of bidirectional communication between gut microorganisms and their host is known as the microbiota-gut-brain axis (MGBA). There is mounting evidence that maintaining gut microbiota homeostasis can frequently enhance the effectiveness of ischemic stroke treatment by modulating immune, metabolic, and inflammatory responses through MGBA. To effectively monitor and cure ischemic stroke, restoring a healthy microbial ecology in the gut may be a critical therapeutic focus. This review highlights mechanistic insights on the MGBA in disease pathophysiology. This review summarizes the role of MGBA signaling in the development of stroke risk factors such as aging, hypertension, obesity, diabetes, and atherosclerosis, as well as changes in the microbiota in experimental or clinical populations. In addition, this review also examines dietary changes, the administration of probiotics and prebiotics, and fecal microbiota transplantation as treatment options for ischemic stroke as potential health benefits. It will become more apparent how the MGBA affects human health and disease with continuing advancements in this emerging field of biomedical sciences.

Immune and inflammatory mechanisms of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease. Immune-mediated infiltration and a destruction of the aortic wall during AAA development plays significant role in the pathogenesis of this disease. While various immune cells had been found in AAA, the mechanisms of their activation and function are still far from being understood. A better understanding of mechanisms regulating the development of aberrant immune cell activation in AAA is essential for the development of novel preventive and therapeutic approaches. In this review we summarize current knowledge about the role of immune cells in AAA and discuss how pathogenic immune cell activation is regulated in this disease.