The gut microbiome and hypertension

Faecal metaproteomics analysis reveals a high cardiovascular risk profile across healthy individuals and heart failure patients

The gut microbiota is a crucial link between diet and cardiovascular disease (CVD). Using fecal metaproteomics, a method that concurrently captures human gut and microbiome proteins, we determined the crosstalk between gut microbiome, diet, gut health, and CVD. Traditional CVD risk factors (age, BMI, sex, blood pressure) explained < 10% of the proteome variance. However, unsupervised human protein-based clustering analysis revealed two distinct CVD risk clusters (low-risk and high-risk) with different blood pressure (by 9 mmHg) and sex-dependent dietary potassium and fiber intake. In the human proteome, the low-risk group had lower angiotensin-converting enzymes, inflammatory proteins associated with neutrophil extracellular trap formation and auto-immune diseases. In the microbial proteome, the low-risk group had higher expression of phosphate acetyltransferase that produces SCFAs, particularly in fiber-fermenting bacteria. This model identified severity across phenotypes in heart failure patients and long-term risk of cardiovascular events in a large population-based cohort. These findings underscore multifactorial gut-to-host mechanisms that may underlie risk factors for CVD.

The role for ω-3 polyunsaturated and short chain fatty acids in hypertension: An updated view on the interaction with gut microbiota

As of 2024, arterial hypertension is still considered the leading modifiable cardiovascular risk factor and, due to high rates of undertreatment and poor blood pressure control, the major contributor to human morbidity and mortality. Development of new treatment options and better interventions in lifestyle correction have become a priority of experimental and clinical research. In the last decades, dietary supplementation of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and generation of gut microbiota-derived short chain fatty acids (SCFAs) have surged as potential and promising interventions for hypertension and cardiovascular prevention. ω-3 PUFAs are considered "essential" fatty acids that can be obtained only from dietary sources. Although previous intervention trials were not consistent in reporting a significant benefit of ω-3 PUFAs, the recent REDUCE-IT trial has provided robust evidence in support of their role in cardiovascular prevention. Recent studies have also identified the intestinal microbiota as a potential player in the pathophysiology and progression of hypertension. Although this might occur through many pathways, generation of SCFAs that is highly dependent on dietary fiber intake is primarily involved, providing an additional target for the development of novel therapeutic strategies. For these reasons, some scientific societies currently recommend dietary supplementation of ω-3 PUFAs and fiber-containing foods in patients with hypertension. In this narrative review, we summarize the results of studies that examined the effects of ω-3 PUFAs and SCFAs on blood pressure, highlighting the mechanisms of action on the vascular system and their possible impact on hypertension, hypertension-related organ damage and, ultimately, cardiovascular outcomes.

Salt-Responsive Gut Microbiota Induces Sex-Specific Blood Pressure Changes

BACKGROUND

Tryptophan metabolism is important in blood pressure regulation. The tryptophan-indole pathway is exclusively mediated by the gut microbiota. ACE2 (angiotensin-converting enzyme 2) participates in tryptophan absorption, and a lack of ACE2 leads to changes in the gut microbiota. The gut microbiota has been recognized as a regulator of blood pressure. Furthermore, there is ample evidence for sex differences in the gut microbiota. However, it is unclear whether such sex differences impact blood pressure differentially through the tryptophan-indole pathway.

METHODS

To study the sex-specific mechanisms of gut microbiota-mediated tryptophan-indole pathway in hypertension, we generated a novel rat model with Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats-associated protein 9)-targeted deletion of Ace2 in the Dahl salt-sensitive rat. Cecal microbiota transfers from donors of both sexes to female S recipients were performed. Also, Dahl salt-sensitive rats of both sexes were orally gavaged with indole to investigate blood pressure response.

RESULTS

The female gut microbiota and its tryptophan-indole pathway exhibited greater buffering capacity when exposed to tryptophan, due to Ace2 deficiency, and salt. In contrast, the male gut microbiota and its tryptophan-indole pathway were more vulnerable. Female rats with male cecal microbiota responded to salt with a higher blood pressure increase compared with those with female cecal microbiota. Indole, a tryptophan-derived metabolite produced by gut bacteria, increased blood pressure in male but not in female rats. Moreover, salt altered host-mediated tryptophan metabolism, characterized by reduced serum serotonin of both sexes and higher levels of kynurenine derivatives in the females.

CONCLUSIONS

We uncovered a novel sex-specific mechanism in the gut microbiota-mediated tryptophan-indole pathway in blood pressure regulation. Salt tipped the tryptophan metabolism between the host and gut microbiota in a sex-dependent manner. Our study provides evidence for a novel concept that gut microbiota and its metabolism play sex-specific roles in the development of salt-sensitive hypertension.

Leveraging metabolism for better outcomes in heart failure

Whilst metabolic inflexibility and substrate constraint have been observed in heart failure for many years, their exact causal role remains controversial. In parallel, many of our fundamental assumptions about cardiac fuel use are now being challenged like never before. For example, the emergence of sodium-glucose cotransporter 2 inhibitor therapy as one of the four 'pillars' of heart failure therapy is causing a revisit of metabolism as a key mechanism and therapeutic target in heart failure. Improvements in the field of cardiac metabolomics will lead to a far more granular understanding of the mechanisms underpinning normal and abnormal human cardiac fuel use, an appreciation of drug action, and novel therapeutic strategies. Technological advances and expanding biorepositories offer exciting opportunities to elucidate the novel aspects of these metabolic mechanisms. Methodologic advances include comprehensive and accurate substrate quantitation such as metabolomics and stable-isotope fluxomics, improved access to arterio-venous blood samples across the heart to determine fuel consumption and energy conversion, high quality cardiac tissue biopsies, biochemical analytics, and informatics. Pairing these technologies with recent discoveries in epigenetic regulation, mitochondrial dynamics, and organ-microbiome metabolic crosstalk will garner critical mechanistic insights in heart failure. In this state-of-the-art review, we focus on new metabolic insights, with an eye on emerging metabolic strategies for heart failure. Our synthesis of the field will be valuable for a diverse audience with an interest in cardiac metabolism.

Advances in uromodulin biology and potential clinical applications

Uromodulin (also known as Tamm-Horsfall protein) is a kidney-specific glycoprotein secreted bidirectionally into urine and into the circulation, and it is the most abundant protein in normal urine. Although the discovery of uromodulin predates modern medicine, its significance in health and disease has been rather enigmatic. Research studies have gradually revealed that uromodulin exists in multiple forms and has important roles in urinary and systemic homeostasis. Most uromodulin in urine is polymerized into highly organized filaments, whereas non-polymeric uromodulin is detected both in urine and in the circulation, and can have distinct roles. The interactions of uromodulin with the immune system, which were initially reported to be a key role of this protein, are now better understood. Moreover, the discovery that uromodulin is associated with a spectrum of kidney diseases, including acute kidney injury, chronic kidney disease and autosomal-dominant tubulointerstitial kidney disease, has further accelerated investigations into the role of this protein. These discoveries have prompted new questions and ushered in a new era in uromodulin research. Here, we delineate the latest discoveries in uromodulin biology and its emerging roles in modulating kidney and systemic diseases, and consider future directions, including its potential clinical applications.

Vascular Cognitive Impairment-The Molecular Basis and Potential Influence of the Gut Microbiota on the Pathological Process

Cognitive impairment is a major healthcare challenge worldwide, with vascular cognitive impairment (VCI) being its second leading cause after Alzheimer's disease. VCI is a heterogeneous group of cognitive disorders resulting from various vascular pathologies. Therefore, it is particularly difficult to determine its underlying cause and exact molecular basis. Nevertheless, the current understanding of the pathophysiological processes underlying VCI has changed and evolved in the last decades. The aim of this narrative review is to summarize the current state of knowledge on VCI pathogenesis and to analyze the potential role of the gut microbiota in this process, considering the most recent scientific reports and in accordance with the current understanding of these processes. Chronic cerebral hypoperfusion, which results in impaired blood supply, i.e., oxygen and nutrient deficiency, is the main underlying mechanism of VCI. Furthermore, chronic cerebral hypoperfusion triggers a cascade of molecular changes, starting with an energy imbalance, leading to glutamate excitotoxicity, acidotoxicity, and oxidative stress. Also, all of the above provoke the activation of microglia and the release of pro-inflammatory cytokines that recruit systemic immune cells and lead to their infiltration into the central nervous system, resulting in neuroinflammation. Blood-brain barrier dysfunction may occur at various stages of chronic cerebral hypoperfusion, ultimately increasing its permeability and allowing potentially toxic substances to enter the brain parenchyma. Gut microbiota and their metabolites, which have been identified in numerous inflammatory conditions, may also influence the pathophysiological processes of VCI.

Alterations in Gut Microbiota and Serum Metabolites in Children with Mycoplasma pneumoniae Pneumonia

Background

Over the past years, there has been a significant increase in the incidence of Mycoplasma pneumoniae (MP) infections, particularly among pediatric patients, nationwide. An emerging body of research has established a link between dysbiosis of the host microbiome and the metabolic functioning of the host, which contributes to the development of respiratory diseases.

Methods

A total of 25 children were included in the study, comprising 15 pneumonia patients and 10 healthy children. Stool samples were collected from all participants to analyze the 16S ribosomal RNA (16S rRNA) gene, while serum samples were prepared for untargeted metabolomics to qualitatively and quantitatively assess short-chain fatty acids.

Results

The gut microbial composition of individuals with Mycoplasma pneumoniae pneumonia (MPP) exhibited significant differences compared to healthy children. Notably, diseased children demonstrated higher microbial diversity and an enrichment of opportunistic pathogens, such as Erysipelatoclostridium and Eggerthella. Analysis revealed elevated levels of two specific short-chain fatty acids, namely acetic acid and isobutyric acid, in the MPP group, suggesting their potential as biomarkers for predicting MP infection. Metabolomic signature analysis identified a significant increase in major classes of glycerophospholipids in the MPP group. Moreover, we identified a total of 750 significant correlations between gut microbiota and circulating serum metabolites. MPP enriched genera Erysipelatoclostridium and Eggerthella, exhibited negative associations with indole-3-butyric acid. Additionally, Eggerthella showed a positive correlation with inflammatory metabolites LPC (18:0).

Discussion

Collectively, these findings provide novel insights into the selection of potential biomarkers and the pathogenesis of MPP in children based on the gut microbiota and systemic circulating metabolites.

Gut Microbe-Generated Metabolite Trimethylamine-N-Oxide and Ischemic Stroke

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite, the production of which in vivo is mainly regulated by dietary choices, gut microbiota, and the hepatic enzyme flavin monooxygenase (FMO), while its elimination occurs via the kidneys. The TMAO level is positively correlated with the risk of developing cardiovascular diseases. Recent studies have found that TMAO plays an important role in the development of ischemic stroke. In this review, we describe the relationship between TMAO and ischemic stroke risk factors (hypertension, diabetes, atrial fibrillation, atherosclerosis, thrombosis, etc.), disease risk, severity, prognostic outcomes, and recurrence and discuss the possible mechanisms by which they interact. Importantly, TMAO induces atherosclerosis and thrombosis through lipid metabolism, foam cell formation, endothelial dysfunction (via inflammation, oxidative stress, and pyroptosis), enhanced platelet hyper-reactivity, and the upregulation and activation of vascular endothelial tissue factors. Although the pathogenic mechanisms underlying TMAO's aggravation of disease severity and its effects on post-stroke neurological recovery and recurrence risk remain unclear, they may involve inflammation, astrocyte function, and pro-inflammatory monocytes. In addition, this paper provides a summary and evaluation of relevant preclinical and clinical studies on interventions regarding the gut-microbiota-dependent TMAO level to provide evidence for the prevention and treatment of ischemic stroke through the gut microbe-TMAO pathway.

Recent advancements in targeting the immune system to treat hypertension

Hypertension is the key leading risk factor for death globally, affecting ∼1.3 billion adults, particularly in low- and middle-income countries. Most people living with hypertension have uncontrolled high blood pressure, increasing their likelihood of cardiovascular events. Significant issues preventing blood pressure control include lack of diagnosis, treatment, and response to existing therapy. For example, monotherapy and combination therapy are often unable to lower blood pressure to target levels. New therapies are urgently required to tackle this issue, particularly those that target the mechanisms behind hypertension instead of treating its symptoms. Acting via an increase in systemic and tissue-specific inflammation, the immune system is a critical contributor to blood pressure regulation and is considered an early mechanism leading to hypertension development. Here, we review the immune system's role in hypertension, evaluate clinical trials that target inflammation, and discuss knowledge gaps in pre-clinical and clinical data. We examine the effects of anti-inflammatory drugs colchicine and methotrexate on hypertension and evaluate the blockade of pro-inflammatory cytokines IL-1β and TNF-α on blood pressure in clinical trials. Lastly, we highlight how we can move forward to target specific components of the immune system to lower blood pressure. This includes targeting isolevuglandins, which accumulate in dendritic cells to promote T cell activation and cytokine production in salt-induced hypertension. We discuss the potential of the dietary fibre-derived metabolites short-chain fatty acids, which have anti-inflammatory and blood pressure-lowering effects via the gut microbiome. This would limit adverse events, leading to improved medication adherence and better blood pressure control.

Primary Prevention Strategy for Non-Communicable Diseases (NCDs) and Their Risk Factors: The Role of Intestinal Microbiota

Non-communicable diseases (NCDs) are the leading cause of morbidity and mortality worldwide. These conditions have numerous health consequences and significantly impact patients' lifestyles. Effective long-term treatment is essential since NCDs are irreversible. Therefore, primary healthcare must be both exclusive and of the highest quality, ensuring comprehensive care. The primary goal should be to improve quality of life with a focus on patients, families, and communities, as most of these diseases can be prevented and controlled, although not cured. Several factors have been linked to individual health, including social, cultural, and economic aspects, lifestyle, and certain environmental factors, including work, that can have positive or negative effects. More of these variables may contribute to the onset of NCDs, which are defined by their chronic nature, propensity for prolongation, and generally slow rate of progression. Examples of NCDs include hypertension, type 2 diabetes (T2D), dyslipidemia, and fatty liver disease linked to metabolic dysfunction. The onset of these diseases has been associated with an imbalance in certain microbial niches, such as the gut, which hosts billions of microorganisms performing multiple metabolic functions, such as the production of metabolites like bile acids (BAs), short-chain fatty acids (SCFAs), and trimethylamine N-oxide (TMAO). Therefore, lifestyle changes and personal habits can significantly impact the gut microbiota (GM), potentially preventing chronic diseases associated with metabolism. NCDs are highly prevalent worldwide, prompting increased attention to strategies for modifying the intestinal microbiota (IM). Approaches such as probiotics, prebiotics, synbiotics, and fecal transplantation (FMT) have demonstrated improvements in the quality of life for individuals with these conditions. Additionally, lifestyle changes and the adoption of healthy habits can significantly impact IM and may help prevent chronic diseases related to metabolism. Therefore, the main aim of this review is to analyze and understand the importance of microbiota intervention in the prevention of non-communicable diseases. R3:A1.

Unlocking the Potential of Brewers' Spent Grain: A Sustainable Model to Use Beer for Better Outcome in Chronic Kidney Disease

The rising global incidence of chronic inflammatory diseases calls for innovative and sustainable medical solutions. Brewers' spent grain (BSG), a byproduct of beer production, presents a unique opportunity in this regard. This review explores the multifaceted health benefits of BSG, with a focus on managing chronic kidney disease (CKD). BSG is identified as a potent prebiotic with potential as a therapeutic agent in CKD. We emphasize the role of gut dysbiosis in CKD and discuss how BSG could help mitigate metabolic derangements resulting from dysbiosis and CKD. Fermentation of BSG further enhances its positive impact on gut health. Incorporating fermented BSG as a key component in preventive health care could promote a more sustainable and healthier future. By optimizing the use of this typically discarded byproduct, we can align proactive health-care strategies with responsible resource management, benefiting both people and the environment.

Polysaccharides from Sacha Inchi shell reduces renal fibrosis in mice by modulating the TGF-β1/Smad pathway and intestinal microbiota

Renal fibrosis is a common pathway involved in the progression of various chronic kidney to end-stage diseases, posing a substantial global public health challenge in the search for effective and safe treatments. This study investigated the effects and mechanisms of sacha inchi shell polysaccharide (SISP) on renal fibrosis induced by a high-salt diet (HSD) in mice. By analysing kidney-related protein pathways and the structure of gut microbiota, we found that SISP significantly reduced urinary protein levels induced by a HSD from 41.08 to 22.95 μg/mL and increased urinary creatinine from 787.43 to 1294.50 μmol/L. It reduced renal interstitial collagen fibres by 11.30 %, thereby improving the kidney function. SISP lowered the mRNA expression of TGF-B1, fibronectin, α-SMA, Smad2/3, and TGFBRII, leading to decreased protein levels of TGF-β1, p-Smad2/3, p-TGFβRII, fibronectin, α-SMA, p-Smad2/3/Smad2/3, and p-TGFβRII/TGFβRII. These changes blocked downstream transcription in the TGF-β1/Smad signalling pathway, thereby attenuating renal fibrosis in HSD mice. In addition, SISP altered the intestinal flora imbalance in HSD mice by reducing the relative abundance of the genera, Akkermansia, Faecalibaculum, and unidentified_Ruminococcaceae, and reversing the decline in the levels of the genera, Lactobacillus and Bacteroides. In conclusion, SISP is a promising nutraceutical for renal fibrosis management.

Effects of bile acids on the growth, composition and metabolism of gut bacteria

Bile acids (BAs) exert a profound influence on the body's pathophysiology by intricately shaping the composition of gut bacteria. However, the complex interplay between BAs and gut microbiota has impeded a systematic exploration of their impact on intestinal bacteria. Initially, we investigated the effects of 21 BAs on the growth of 65 gut bacterial strains in vitro. Subsequently, we examined the impact of BAs on the overall composition of intestinal bacteria, both in vivo and in vitro. The results unveiled distinct effects of various BAs on different intestinal strains and their diverse impacts on the composition of gut bacteria. Mechanistically, the inhibition of intestinal strains by BAs occurs through the accumulation of these acids within the strains. The intracellular accumulation of deoxycholic acid (DCA) significantly influenced the growth of intestinal bacteria by impacting ribosome transcription and amino-acid metabolism. The metabolomic analysis underscores the pronounced impact of DCA on amino-acid profiles in both in vivo and in vitro settings. This study not only elucidates the effects of BAs on a diverse range of bacterial strains and their role in shaping the gut microbiota but also reveals underlying mechanisms essential for understanding and maintaining a healthy gut microbiota.

Identification of metabolites from the gut microbiota in hypertension via network pharmacology and molecular docking

Hypertension is the most prevalent cardiovascular disease, affecting one-third of adults. All antihypertensive drugs have potential side effects. Gut metabolites influence hypertension. The objective of this study was to identify antihypertensive gut metabolites through network pharmacology and molecular docking techniques and to validate their antihypertensive mechanisms via in vitro experiments. A total of 10 core antihypertensive targets and 18 gut metabolites that act on hypertension were identified. Four groups of protein metabolites, namely, CXCL8-baicalein, CXCL8-baicalin, CYP1A1-urolithin A, and PTGS2-equol, which have binding energies of - 7.7, - 8.5, - 7.2, and - 8.8 kcal-mol-1, respectively, were found to have relatively high affinities. Based on its drug-likeness properties in silico and toxicological properties, equol was identified as a potential antihypertensive metabolite. On the basis of the results of network pharmacology and molecular docking, equol may exert antihypertensive effects by regulating the IL-17 signaling pathway and PTGS2. A phenylephrine-induced H9c2 cell model was subsequently utilized to verify that equol inhibits cell hypertrophy (P < 0.05) by inhibiting the IL-17 signaling pathway and PTGS2 (P < 0.05). This study demonstrated that equol has the potential to be developed as a novel therapeutic agent for the treatment of hypertension.

Genetic association between gut microbiome and blood pressure and blood cell count as mediator: A two-step Mendelian randomization analysis

BACKGROUND

Previous studies have established a genetic link between gut microbiota and hypertension, but whether blood cell count plays a mediating role in this remains unknown. This study aims to explore genetic associations and causal factors involving the gut microbiome, peripheral blood cell count, and blood pressure.

METHODS

We utilized summary statistics derived from genome-wide association studies to conduct a two-sample mediation Mendelian randomization analysis (https://gwas.mrcieu.ac.uk/). We applied inverse variance weighted (IVW) estimation method as the primary method, along with MR Egger, Weighted median, Simple mode and Weighted mode as complementary methods. To ensure the robustness of the results, several sensitivity analyses were conducted.

RESULTS

Genetic variants significantly associated with the microbiome, blood pressure, or peripheral blood cell counts were selected as instrumental variables. Fourteen microbial taxa were found to have suggestive associations with diastolic blood pressure (DBP), while fifteen microbial taxa showed suggestive associations with systolic blood pressure (SBP). Meanwhile, red blood cell count, lymphocyte count, and platelet count were identified to mediate the influence of the gut microbiome on blood pressure. Specifically, red cell count was identified to mediate the effects of the phylum Cyanobacteria on DBP (mediated proportion: 8.262 %). Lymphocyte count was found mediate the effects of the genus Subdoligranulum (mediated proportion: 2.642 %) and genus Collinsella (mediated proportion: 2.749 %) on SBP. Additionally, platelet count was found to mediate the relationship between the genus Eubacterium ventriosum group and SBP, explaining 3.421 % of the mediated proportion.

CONCLUSIONS

Our findings highlighted that gut microbiota may have causal influence on the blood pressure by modulating blood cell counts, which sheds new light on the pathogenesis and potential clinical interventions through the intricate axis of gut microbiome, blood cell counts, and blood pressure.

The role of gut microbiome in mediating the effect of inflammatory bowel disease on hypertension: a two-step, two-sample Mendelian randomization study

Objective

Investigating the causal connection that exists between inflammatory bowel disease (IBD) and hypertension (HT). To gain a deeper insight into the correlation among IBD, gut microbiota, and HT, we conducted a two-step, two-sample Mendelian randomization study.

Methods

An investigation of genome-wide association study (GWAS) summary-level data was utilized to conduct a two-sample Mendelian randomization (MR) analysis of genetically predicted inflammatory bowel disease: (12,882cases, 21,770controls) on Systolic/Diastolic blood pressure (N = 2,564). Subsequently, two-step MR analyses revealed that the relationship between IBD and SBP was partly mediated by Faecalicatena glycyrrhizinilyticum. The robustness of the findings was confirmed through several sensitivity assessments.

Results

This MR study showed that increase in genetically predicted IBD was associated with higher risk of genetically predicted SBP (OR: 1.08, 95% CI: 1.01-1.16, P < 0.05) and DBP (OR: 1.09, 95% CI: 1.02-1.17, P < 0.05), respectively. Inverse variance weighted (IVW) MR analysis also showed that increase in genetically predicted IBD was associated with higher abundance Faecalicatena glycyrrhizinilyticum (OR: 1.03, 95% CI: 1.01-1.04, P < 0.05), which subsequently associated with increased SBP risk (OR: 1.42, 95% CI: 1.06-1.9, P < 0.05). Faecalicatena glycyrrhizinilyticum abundance in stool was responsible for mediating 11% of the genetically predicted IBD on SBP.

Conclusion

The research proposed a causal link between Inflammatory Bowel Disease (IBD) and Hypertension (HT), with a little percentage of the impact being influenced by Faecalicatena glycyrrhizinilyticum in stool. Mitigating gut microbiome may decrease the heightened risk of hypertension in people with inflammatory bowel disease.

Berberine ameliorates vascular dysfunction by downregulating TMAO-endoplasmic reticulum stress pathway via gut microbiota in hypertension

The gut microbial metabolite trimethylamine N-oxide (TMAO) is regarded as a novel risk factor for hypertension. Berberine (BBR) exerts cardiovascular protective effects by regulating the gut microbiota-metabolite production pathway. However, whether and how BBR alleviates TMAO-induced vascular dysfunction in hypertension remains unclear. In the present study, we observed that plasma TMAO and related bacterial abundance were significantly elevated and negatively correlated with vascular function in 86 hypertensive patients compared with 46 normotensive controls. TMAO activated endoplasmic reticulum stress (ERS) signaling pathway to promote endothelial cell dysfunction and apoptosis in vitro. BBR (100, 200 mg · kg-1 ·d-1) for 4 weeks ameliorates TMAO-induced vascular dysfunction and ERS activation in a choline-angiotensin II hypertensive mouse model. We found that plasma TMAO levels in 15 hypertensive patients treated with BBR (0.4 g, tid) were reduced by 8.8 % and 16.7 % at months 1 and 3, respectively, compared with pretreatment baseline. The oral BBR treatment also improved vascular function and lowered blood pressure. Faecal 16 S rDNA showed that BBR altered the gut bacterial composition and reduced the abundance of CutC/D bacteria in hypertensive mice and patients. In vitro bacterial cultures and enzyme reaction systems indicated that BBR inhibited the biosynthesis of TMAO precursor in the gut microbiota by binding to and inhibiting the activity of CutC/D enzyme. Our results indicate that BBR improve vascular dysfunction at least partially by decreasing TMAO via regulation of the gut microbiota in hypertension.

Constipation is associated with an increased risk of major adverse cardiac events in a UK population

Traditional cardiovascular risk factors, including hypertension, only explain part of major adverse cardiac events (MACEs). Understanding what other risk factors contribute to MACE is essential for prevention. Constipation shares common risk factors with hypertension and is associated with an increased risk of several cardiovascular diseases. We hypothesized that constipation is an underappreciated risk factor for MACE. We used the population healthcare and genomic data in the UK Biobank (n = 408,354) to study the contribution of constipation (ICD10 K59.0) to the risk of MACE, defined by any episode of acute coronary syndrome (ACS), ischemic stroke, and heart failure (HF). Analyses were controlled for traditional cardiovascular risk factors. We also assessed genetic correlations (rg) between constipation and MACE. Constipation cases (n = 23,814) exhibited a significantly higher risk of MACE compared with those with normal bowel habits [odds ratio (OR) = 2.15, P < 1.00 × 10-300]. Constipation was also significantly associated with individual MACE subgroups, in order: HF (OR = 2.72, P < 1.00 × 10-300), ischemic stroke (OR = 2.36, P = 2.02 × 10-230), and ACS (OR = 1.62, P = 5.82 × 10-113). In comparison with patients with constipation-free hypertension, patients with hypertension with constipation showed significantly higher odds of MACE (OR = 1.68, P = 1.05 × 10-136) and a 34% increased risk of MACE occurrence (P = 2.3 × 10-50) after adjustment for medications that affect gut motility and other traditional cardiovascular risk factors. Finally, we detected positive genetic correlations between constipation and MACE subgroups ACS (rg = 0.27, P = 2.12 × 10-6), ischemic stroke (rg = 0.23, P = 0.011), and HF (rg = 0.21, P = 0.0062). We identified constipation as a potential risk factor independently associated with higher MACE prevalence. These findings warrant further studies on their causal relationship and identification of pathophysiological mechanisms.NEW & NOTEWORTHY Analyzing 408,354 participants of the UK Biobank, we show that constipation cases exhibited a significantly higher risk of major adverse cardiac events (MACEs) than those with regular bowel habits. In comparison with patients with constipation-free hypertension, patients with hypertension with constipation showed significantly higher odds of MACE and a 34% increased risk of subsequent MACE occurrence. Finally, we detected positive genetic correlations between constipation and MACE. This association holds potential for therapeutic exploitation and prevention based on individuals' risk assessment.

A systematic framework for understanding the microbiome in human health and disease: from basic principles to clinical translation

The human microbiome is a complex and dynamic system that plays important roles in human health and disease. However, there remain limitations and theoretical gaps in our current understanding of the intricate relationship between microbes and humans. In this narrative review, we integrate the knowledge and insights from various fields, including anatomy, physiology, immunology, histology, genetics, and evolution, to propose a systematic framework. It introduces key concepts such as the 'innate and adaptive genomes', which enhance genetic and evolutionary comprehension of the human genome. The 'germ-free syndrome' challenges the traditional 'microbes as pathogens' view, advocating for the necessity of microbes for health. The 'slave tissue' concept underscores the symbiotic intricacies between human tissues and their microbial counterparts, highlighting the dynamic health implications of microbial interactions. 'Acquired microbial immunity' positions the microbiome as an adjunct to human immune systems, providing a rationale for probiotic therapies and prudent antibiotic use. The 'homeostatic reprogramming hypothesis' integrates the microbiome into the internal environment theory, potentially explaining the change in homeostatic indicators post-industrialization. The 'cell-microbe co-ecology model' elucidates the symbiotic regulation affecting cellular balance, while the 'meta-host model' broadens the host definition to include symbiotic microbes. The 'health-illness conversion model' encapsulates the innate and adaptive genomes' interplay and dysbiosis patterns. The aim here is to provide a more focused and coherent understanding of microbiome and highlight future research avenues that could lead to a more effective and efficient healthcare system.

MicroHDF: predicting host phenotypes with metagenomic data using a deep forest-based framework

The gut microbiota plays a vital role in human health, and significant effort has been made to predict human phenotypes, especially diseases, with the microbiota as a promising indicator or predictor with machine learning (ML) methods. However, the accuracy is impacted by a lot of factors when predicting host phenotypes with the metagenomic data, e.g. small sample size, class imbalance, high-dimensional features, etc. To address these challenges, we propose MicroHDF, an interpretable deep learning framework to predict host phenotypes, where a cascade layers of deep forest units is designed for handling sample class imbalance and high dimensional features. The experimental results show that the performance of MicroHDF is competitive with that of existing state-of-the-art methods on 13 publicly available datasets of six different diseases. In particular, it performs best with the area under the receiver operating characteristic curve of 0.9182 ± 0.0098 and 0.9469 ± 0.0076 for inflammatory bowel disease (IBD) and liver cirrhosis, respectively. Our MicroHDF also shows better performance and robustness in cross-study validation. Furthermore, MicroHDF is applied to two high-risk diseases, IBD and autism spectrum disorder, as case studies to identify potential biomarkers. In conclusion, our method provides an effective and reliable prediction of the host phenotype and discovers informative features with biological insights.

Influence of angiotensin II on the gut microbiome: modest effects in comparison to experimental factors

AIMS

Animal models are regularly used to test the role of the gut microbiome in hypertension. Small-scale pre-clinical studies have investigated changes to the gut microbiome in the angiotensin II hypertensive model. However, the gut microbiome is influenced by internal and external experimental factors, which are not regularly considered in the study design. Once these factors are accounted for, it is unclear if microbiome signatures are reproduceable. We aimed to determine the influence of angiotensin II treatment on the gut microbiome using a large and diverse cohort of mice and to quantify the magnitude by which other factors contribute to microbiome variations.

METHODS AND RESULTS

We conducted a retrospective study to establish a diverse mouse cohort resembling large human studies. We sequenced the V4 region of the 16S rRNA gene from 538 samples across the gastrointestinal tract of 303 male and female C57BL/6J mice randomized into sham or angiotensin II treatment from different genotypes, diets, animal facilities, and age groups. Analysing over 17 million sequencing reads, we observed that angiotensin II treatment influenced α-diversity (P = 0.0137) and β-diversity (i.e. composition of the microbiome, P < 0.001). Bacterial abundance analysis revealed patterns consistent with a reduction in short-chain fatty acid producers, microbial metabolites that lower blood pressure. Furthermore, animal facility, genotype, diet, age, sex, intestinal sampling site, and sequencing batch had significant effects on both α- and β-diversity (all P < 0.001). Sampling site (6.8%) and diet (6%) had the largest impact on the microbiome, while angiotensin II and sex had the smallest effect (each 0.4%).

CONCLUSION

Our large-scale data confirmed findings from small-scale studies that angiotensin II impacted the gut microbiome. However, this effect was modest relative to most of the other factors studied. Accounting for these factors in future pre-clinical hypertensive studies will increase the likelihood that microbiome findings are replicable and translatable.

Aortic aneurysm: pathophysiology and therapeutic options

Aortic aneurysm (AA) is an aortic disease with a high mortality rate, and other than surgery no effective preventive or therapeutic treatment have been developed. The renin-angiotensin system (RAS) is an important endocrine system that regulates vascular health. The ACE2/Ang-(1-7)/MasR axis can antagonize the adverse effects of the activation of the ACE/Ang II/AT1R axis on vascular dysfunction, atherosclerosis, and the development of aneurysms, thus providing an important therapeutic target for the prevention and treatment of AA. However, products targeting the Ang-(1-7)/MasR pathway still lack clinical validation. This review will outline the epidemiology of AA, including thoracic, abdominal, and thoracoabdominal AA, as well as current diagnostic and treatment strategies. Due to the highest incidence and most extensive research on abdominal AA (AAA), we will focus on AAA to explain the role of the RAS in its development, the protective function of Ang-(1-7)/MasR, and the mechanisms involved. We will also describe the roles of agonists and antagonists, suggest improvements in engineering and drug delivery, and provide evidence for Ang-(1-7)/MasR's clinical potential, discussing risks and solutions for clinical use. This study will enhance our understanding of AA and offer new possibilities and promising targets for therapeutic intervention.

Differential gene expression in the kidneys of SHR and WKY rats after intravenous administration of Akkermansia muciniphila-derived extracellular vesicles

Although Akkermansia muciniphila (Am) plays a beneficial role as a probiotic in the treatment of metabolic syndrome, the mechanisms remain elusive. We tested the hypothesis that Am extracellular vesicles (AmEVs) protect against hypertension through modulation of gene expression in the kidneys of spontaneously hypertensive rats (SHRs). Extracellular vesicles purified from anaerobically cultured Am (1.0 × 108 or 1.0 × 109 particles/kg) or vehicles were injected into the tail veins of Wistar-Kyoto rats (WKYs) and SHRs weekly for 4 weeks. Renal cortical tissues isolated from both rat strains were analyzed by trichrome stain and RT-qPCR. AmEVs protect against the development of hypertension in SHRs without a serious adverse reaction. AmEVs increased the expression of vasocontracting Agt and At1ar as well as vasodilating At2r, Mas1 and Nos2 in the kidneys of both strains. These results indicate that AmEVs have a protective effect against hypertension without a serious adverse reaction. Therefore, it is foreseen that AmEVs may be utilized as a novel therapeutic for the treatment of hypertension.

Lifestyle Changes in Aging and their Potential Impact on POAG

Primary open angle glaucoma is a primary mitochondrial disease with oxidative stress triggering neuroinflammation, eventually resulting in neurodegeneration. This affects many other areas of the brain in addition to the visual system. Aging also leads to inflammaging - a low-grade chronic inflammatory reaction in mitochondrial dysfunction, so these inflammatory processes overlap in the aging process and intensify pathophysiological processes associated with glaucoma. Actively counteracting these inflammatory events involves optimising treatment for any manifest systemic diseases while maintaining chronobiology and improving the microbiome. Physical and mental activity also provides support. This requires a holistic approach towards optimising neurodegeneration treatment in primary open angle glaucoma in addition to reducing intraocular pressure according personalised patient targets.

Broadening horizons: intestinal microbiota as a novel biomarker and potential treatment for hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy (HDP) are severe complications of pregnancy with high morbidity and are a major cause of increased maternal and infant morbidity and mortality. Currently, there is a lack of effective early diagnostic indicators and safe and effective preventive strategies for HDP in clinical practice, except for monitoring maternal blood pressure levels, the degree of proteinuria, organ involvement and fetal conditions. The intestinal microbiota consists of the gut flora and intestinal environment, which is the largest microecosystem of the human body and participates in material and energy metabolism, gene expression regulation, immunity regulation, and other functions. During pregnancy, due to changes in hormone levels and altered immune function, the intestinal microecological balance is affected, triggering HDP. A dysregulated intestinal microenvironment influences the composition and distribution of the gut flora and changes the intestinal barrier, driving beneficial or harmful bacterial metabolites and inflammatory responses to participate in the development of HDP and promote its malignant development. When the gut flora is dysbiotic and affects blood pressure, supplementation with probiotics and dietary fiber can be used to intervene. In this review, the interaction between the intestinal microbiota and HDP was investigated to explore the feasibility of the gut flora as a novel biomarker of HDP and to provide a new strategy and basis for the prevention and treatment of clinical HDP.

Advances in the treatment of diabetic peripheral neuropathy by modulating gut microbiota with traditional Chinese medicine

Diabetic peripheral neuropathy (DPN) is one of the strongest risk factors for diabetic foot ulcers (neuropathic ulcerations) and the existing ulcers may further deteriorate due to the damage to sensory neurons. Moreover, the resulting numbness in the limbs causes difficulty in discovering these ulcerations in a short time. DPN is associated with gut microbiota dysbiosis. Traditional Chinese medicine (TCM) compounds such as Shenqi Dihuang Decoction, Huangkui Capsules and Qidi Tangshen Granules can reduce the clinical symptoms of diabetic nephropathy by modulating gut microbiota. The current review discusses whether TCM compounds can reduce the risk of DPN by improving gut mic-robiota.

Functional modification of gut bacteria for disease diagnosis and treatment

Intestinal bacteria help keep humans healthy by regulating lipid and glucose metabolism as well as the immunological and neurological systems. Oral treatment using intestinal bacteria is limited by the high acidity of stomach fluids and the immune system's attack on foreign bacteria. Scientists have created coatings and workarounds to overcome these limitations and improve bacterial therapy. These preparations have demonstrated promising outcomes, with advances in synthetic biology and optogenetics improving their focused colonization and controlled release. Engineering bacteria preparations have become a revolutionary therapeutic approach that converts intestinal bacteria into cellular factories for medicinal chemical synthesis. The present paper discusses various aspects of engineering bacteria preparations, including wrapping materials, biomedical uses, and future developments.

Lactoferrin Supplementation during Pregnancy and Lactation Protects Adult Male Rat Offspring from Hypertension Induced by Maternal Adenine Diet

Lactoferrin, a glycoprotein derived from breastmilk, is recognized for its health benefits in infants and children; however, its protective effects when administered during gestation and lactation against offspring hypertension remain unclear. This study aimed to investigate whether maternal lactoferrin supplementation could prevent hypertension in offspring born to mothers with chronic kidney disease (CKD), with a focus on nitric oxide (NO), renin-angiotensin system (RAS) regulation, and alterations in gut microbiota and short-chain fatty acids (SCFAs). Prior to pregnancy, female rats were subjected to a 0.5% adenine diet for 3 weeks to induce CKD. During pregnancy and lactation, pregnant rats received one of four diets: normal chow, 0.5% adenine diet, 10% lactoferrin diet, or adenine diet supplemented with lactoferrin. Male offspring were euthanized at 12 weeks of age (n = 8 per group). Supplementation with lactoferrin during gestation and lactation prevented hypertension in adult offspring induced by a maternal adenine diet. The maternal adenine diet caused a decrease in the index of NO availability, which was restored by 67% with maternal LF supplementation. Additionally, LF was related to the regulation of the RAS, as evidenced by a reduced renal expression of renin and the angiotensin II type 1 receptor. Combined maternal adenine and LF diets altered beta diversity, shifted the offspring's gut microbiota, decreased propionate levels, and reduced the renal expression of SCFA receptors. The beneficial effects of lactoferrin are likely mediated through enhanced NO availability, rebalancing the RAS, and alterations in gut microbiota composition and SCFAs. Our findings suggest that maternal lactoferrin supplementation improves hypertension in offspring in a model of adenine-induced CKD, bringing us closer to potentially translating lactoferrin supplementation clinically for children born to mothers with CKD.

Resolution of inflammation, an active process to restore the immune microenvironment balance: A novel drug target for treating arterial hypertension

The resolution of inflammation, the other side of the inflammatory response, is defined as an active and highly coordinated process that promotes the restoration of immune microenvironment balance and tissue repair. Inflammation resolution involves several key processes, including dampening proinflammatory signaling, specialized proresolving lipid mediator (SPM) production, nonlipid proresolving mediator production, efferocytosis and regulatory T-cell (Treg) induction. In recent years, increasing attention has been given to the effects of inflammation resolution on hypertension. Furthermore, our previous studies reported the antihypertensive effects of SPMs. Therefore, in this review, we aim to summarize and discuss the detailed association between arterial hypertension and inflammation resolution. Additional, the association between gut microbe-mediated immune and hypertension is discussed. This findings suggested that accelerating the resolution of inflammation can have beneficial effects on hypertension and its related organ damage. Exploring novel drug targets by focusing on various pathways involved in accelerating inflammation resolution will contribute to the treatment and control of hypertensive diseases in the future.

The gut-immune axis during hypertension and cardiovascular diseases

The gut-immune axis is a relatively novel phenomenon that provides mechanistic links between the gut microbiome and the immune system. A growing body of evidence supports it is key in how the gut microbiome contributes to several diseases, including hypertension and cardiovascular diseases (CVDs). Evidence over the past decade supports a causal link of the gut microbiome in hypertension and its complications, including myocardial infarction, atherosclerosis, heart failure, and stroke. Perturbations in gut homeostasis such as dysbiosis (i.e., alterations in gut microbial composition) may trigger immune responses that lead to chronic low-grade inflammation and, ultimately, the development and progression of these conditions. This is unsurprising, as the gut harbors one of the largest numbers of immune cells in the body, yet is a phenomenon not entirely understood in the context of cardiometabolic disorders. In this review, we discuss the role of the gut microbiome, the immune system, and inflammation in the context of hypertension and CVD, and consolidate current evidence of this complex interplay, whilst highlighting gaps in the literature. We focus on diet as one of the major modulators of the gut microbiota, and explain key microbial-derived metabolites (e.g., short-chain fatty acids, trimethylamine N-oxide) as potential mediators of the communication between the gut and peripheral organs such as the heart, arteries, kidneys, and the brain via the immune system. Finally, we explore the dual role of both the gut microbiome and the immune system, and how they work together to not only contribute, but also mitigate hypertension and CVD.

Harnessing human microbiomes for disease prediction

The human microbiome has been increasingly recognized as having potential use for disease prediction. Predicting the risk, progression, and severity of diseases holds promise to transform clinical practice, empower patient decisions, and reduce the burden of various common diseases, as has been demonstrated for cardiovascular disease or breast cancer. Combining multiple modifiable and non-modifiable risk factors, including high-dimensional genomic data, has been traditionally favored, but few studies have incorporated the human microbiome into models for predicting the prospective risk of disease. Here, we review research into the use of the human microbiome for disease prediction with a particular focus on prospective studies as well as the modulation and engineering of the microbiome as a therapeutic strategy.

Recommendations for the Use of Dietary Fiber to Improve Blood Pressure Control

According to several international, regional, and national guidelines on hypertension, lifestyle interventions are the first-line treatment to lower blood pressure (BP). Although diet is one of the major lifestyle modifications described in hypertension guidelines, dietary fiber is not specified. Suboptimal intake of foods high in fiber, such as in Westernized diets, is a major contributing factor to mortality and morbidity of noncommunicable diseases due to higher BP and cardiovascular disease. In this review, we address this deficiency by examining and advocating for the incorporation of dietary fiber as a key lifestyle modification to manage elevated BP. We explain what dietary fiber is, review the existing literature that supports its use to lower BP and prevent cardiovascular disease, describe the mechanisms involved, propose evidence-based target levels of fiber intake, provide examples of how patients can achieve the recommended targets, and discuss outstanding questions in the field. According to the evidence reviewed here, the minimum daily dietary fiber for adults with hypertension should be >28 g/day for women and >38 g/day for men, with each extra 5 g/day estimated to reduce systolic BP by 2.8 mm Hg and diastolic BP by 2.1 mm Hg. This would support a healthy gut microbiota and the production of gut microbiota-derived metabolites called short-chain fatty acids that lower BP. Awareness about dietary fiber targets and how to achieve them will guide medical teams on better educating patients and empowering them to increase their fiber intake and, as a result, lower their BP and cardiovascular disease risk.

Possible Role of Gut Microbiota Alterations in Myocardial Fibrosis and Burden of Heart Failure in Hypertensive Heart Disease

Epidemiological studies have revealed that hypertensive heart disease is a major risk factor for heart failure, and its heart failure burden is growing rapidly. The need to act in the face of this threat requires first an understanding of the multifactorial origin of hypertensive heart disease and second an exploration of new mechanistic pathways involved in myocardial alterations critically involved in cardiac dysfunction and failure (eg, myocardial interstitial fibrosis). Increasing evidence shows that alterations of gut microbiota composition and function (ie, dysbiosis) leading to changes in microbiota-derived metabolites and impairment of the gut barrier and immune functions may be involved in blood pressure elevation and hypertensive organ damage. In this review, we highlight recent advances in the potential contribution of gut microbiota alterations to myocardial interstitial fibrosis in hypertensive heart disease through blood pressure-dependent and blood pressure-independent mechanisms. Achievements in this field should open a new path for more comprehensive treatment of myocardial interstitial fibrosis in hypertensive heart disease and, thus, for the prevention of heart failure.

Altered gut microbiota and metabolite profiles provide clues in understanding resistant hypertension

BACKGROUND

Resistant hypertension is a severe phenotype in hypertension that may be driven by interactions between genetic and environmental factors. Specific changes in gut microbiota and metabolites have been shown to influence cardiovascular disease progression. However, microbial and metabolomic changes associated with resistant hypertension remain elusive.

METHODS

In this study, the gut microbiome of 30 participants with resistant hypertension, 30 with controlled hypertension, and 30 nonhypertension was characterized using 16S rRNA amplicon sequencing. In addition, the serum metabolome of the same population was assessed by untargeted metabolomics.

RESULTS

The alpha diversity of microbiome in the resistant hypertension decreased, and changes were also observed in the composition of the gut microbiota. The resistant hypertension group was characterized by elevated levels of Actinobacteitia and Proteobacteria. Twenty-three genera were found to have significantly different abundances between resistant hypertension and controlled hypertension, as well as 55 genera with significantly different abundances between resistant hypertension and nonhypertension. Compared with the controlled hypertension group, the genera Rothia and Sharpea in resistant hypertension were more abundant. Compared with the nonhypertension group, the genera Escherichia-Shigella , Lactobacillus , Enterococcus were more abundant. Untargeted metabolomics provided distinctly different serum metabolic profiles for the three groups and identified a range of differential metabolites. These metabolites were mainly associated with the pathway of glycerophospholipid metabolism. Furthermore, correlation analysis provided evidence of new interactions between gut microbiota and metabolites in the resistant hypertension.

CONCLUSION

In conclusion, our study provides a comprehensive understanding of the resistant hypertension gut microbiota and metabolites, suggesting that treatment resistance in resistant hypertension patients may be related to the gut microbiota and serum metabolites.

Gut microbiota: a potential new regulator of hypertension

Hypertension is a significant risk factor for cardiovascular and cerebrovascular diseases and has become a global public health concern. Although hypertension results from a combination of factors, the specific mechanism is still unclear. However, increasing evidence suggests that gut microbiota is closely associated with the development of hypertension. We provide a summary of the composition and physiological role of gut microbiota. We then delve into the mechanism of gut microbiota and its metabolites involved in the occurrence and development of hypertension. Finally, we review various regimens for better-controlling hypertension from the diet, exercise, drugs, antibiotics, probiotics, and fecal transplantation perspectives.

Pathophysiology of primary hypertension in children and adolescents

The progress in research on the physiology of the cardiovascular system made in the last 100 years allowed for the development of the pathogenesis not only of secondary forms of hypertension but also of primary hypertension. The main determinants of blood pressure are described by the relationship between stroke volume, heart rate, peripheral resistance, and arterial stiffness. The theories developed by Guyton and Folkow describe the importance of the volume factor and total peripheral resistance. However, none of them fully presents the pathogenesis of essential hypertension. The multifactorial model of primary hypertension pathogenesis developed by Irving Page in the 1940s, called Page's mosaic, covers most of the pathophysiological phenomena observed in essential hypertension. The most important pathophysiological phenomena included in Page's mosaic form a network of interconnected "nodes". New discoveries both from experimental and clinical studies made in recent decades have allowed the original Page mosaic to be modified and the addition of new pathophysiological nodes. Most of the clinical studies confirming the validity of the multifactorial pathogenesis of primary hypertension concern adults. However, hypertension develops in childhood and is even perinatally programmed. Therefore, the next nodes in Page's mosaic should be age and perinatal factors. This article presents data from pediatric clinical trials describing the most important pathophysiological processes associated with the development of essential hypertension in children and adolescents.

Influence of gut microbiome on metabolic diseases: a new perspective based on microgravity

Purpose

Microgravity, characterized by gravity levels of 10-3-10-6g, has been found to significantly impair various physiological systems in astronauts, including cardiovascular function, bone density, and metabolism. With the recent surge in human spaceflight, understanding the impact of microgravity on biological health has become paramount.

Methods

A comprehensive literature search was performed using the PubMed database to identify relevant publications pertaining to the interplay between gut microbiome, microgravity, space environment, and metabolic diseases.

Results

This comprehensive review primarily focuses on the progress made in investigating the gut microbiome and its association with metabolic diseases under microgravity conditions. Microgravity induces notable alterations in the composition, diversity, and functionality of the gut microbiome. These changes hold direct implications for metabolic disorders such as cardiovascular disease (CVD), bone metabolism disorders, energy metabolism dysregulation, liver dysfunction, and complications during pregnancy.

Conclusion

This novel perspective is crucial for preparing for deep space exploration and interstellar migration, where understanding the complex interplay between the gut microbiome and metabolic health becomes indispensable.

Commensal microbiota regulate aldosterone

The gut microbiome regulates many important host physiological processes associated with cardiovascular health and disease; however, the impact of the gut microbiome on aldosterone is unclear. Investigating whether gut microbiota regulate aldosterone can offer novel insights into how the microbiome affects blood pressure. In this study, we aimed to determine whether gut microbiota regulate host aldosterone. We used enzyme-linked immunosorbent assays (ELISAs) to assess plasma aldosterone and plasma renin activity (PRA) in female and male mice in which gut microbiota are intact, suppressed, or absent. In addition, we examined urinary aldosterone. Our findings demonstrated that when the gut microbiota is suppressed following antibiotic treatment, there is an increase in plasma and urinary aldosterone in both female and male mice. In contrast, an increase in PRA is seen only in males. We also found that when gut microbiota are absent (germ-free mice), plasma aldosterone is significantly increased compared with conventional animals (in both females and males), but PRA is not. Understanding how gut microbiota influence aldosterone levels could provide valuable insights into the development and treatment of hypertension and/or primary aldosteronism. This knowledge may open new avenues for therapeutic interventions, such as probiotics or dietary modifications to help regulate blood pressure via microbiota-based changes to aldosterone.NEW & NOTEWORTHY We explore the role of the gut microbiome in regulating aldosterone, a hormone closely linked to blood pressure and cardiovascular disease. Despite the recognized importance of the gut microbiome in host physiology, the relationship with circulating aldosterone remains largely unexplored. We demonstrate that suppression of gut microbiota leads to increased levels of plasma and urinary aldosterone. These findings underscore the potential of the gut microbiota to influence aldosterone regulation, suggesting new possibilities for treating hypertension.

Role of sulfidogenic members of the gut microbiota in human disease

The human gut flora comprises a dynamic network of bacterial species that coexist in a finely tuned equilibrium. The interaction with intestinal bacteria profoundly influences the host's development, metabolism, immunity, and overall health. Furthermore, dysbiosis, a disruption of the gut microbiota, can induce a variety of diseases, not exclusively associated with the intestinal tract. The increased consumption of animal protein, high-fat and high-sugar diets in Western countries has been implicated in the rise of chronic and inflammatory illnesses associated with dysbiosis. In particular, this diet leads to the overgrowth of sulfide-producing bacteria, known as sulfidogenic bacteria, which has been linked to inflammatory bowel diseases and colorectal cancer, among other disorders. Sulfidogenic bacteria include sulfate-reducing bacteria (Desulfovibrio spp.) and Bilophila wadsworthia among others, which convert organic and inorganic sulfur compounds to sulfide through the dissimilatory sulfite reduction pathway. At high concentrations, sulfide is cytotoxic and disrupts the integrity of the intestinal epithelium and mucus barrier, triggering inflammation. Besides producing sulfide, B. wadsworthia has revealed significant pathogenic potential, demonstrated in the ability to cause infection, adhere to intestinal cells, promote inflammation, and compromise the integrity of the colonic mucus layer. This review delves into the mechanisms by which taurine and sulfide-driven gut dysbiosis contribute to the pathogenesis of sulfidogenic bacteria, and discusses the role of these gut microbes, particularly B. wadsworthia, in human diseases.

Na and K Intake from Lunches Served in a Japanese Company Cafeteria and the Estimated Improvement in the Dietary Na/K Ratio Using Low-Na/K Seasonings and Dairy to Prevent Hypertension

The excessive intake of sodium (Na) and insufficient intake of potassium (K) are major concerns in the prevention of hypertension. Using low-Na/K seasonings (reducing 25% of the NaCl and adding K salt) may improve the dietary Na/K ratio and help prevent hypertension. To devise an intervention study using low-Na/K seasonings at a company cafeteria, we calculated the Na and K contents of the meals served at the cafeteria and estimated changes in the intakes when suitable low-Na/K seasonings were used. We also considered using milk as a good source of K. We used an ingredient list of a company cafeteria and calculated Na and K contents in each dish. The average amounts of NaCl and K per use were 5.04 g and 718 mg, respectively. Seasonings contributed 70.9% of the NaCl. With the use of low-Na/K seasonings, an estimated reduction in NaCl of 0.8 g/day and an estimated increase in K of 308 mg/day was achieved. With an additional serving (200 mL) of milk, NaCl was reduced by 0.57 g/day and K was increased by 610 mg/day, with an overall decrease in the dietary Na/K ratio from 3.20 to 2.40. The use of low-Na/K seasonings and dairy may improve the dietary Na/K ratio among cafeteria users and help prevent hypertension.

Role of gut microbiota in doxorubicin-induced cardiotoxicity: from pathogenesis to related interventions

Doxorubicin (DOX) is a broad-spectrum and highly efficient anticancer agent, but its clinical implication is limited by lethal cardiotoxicity. Growing evidences have shown that alterations in intestinal microbial composition and function, namely dysbiosis, are closely linked to the progression of DOX-induced cardiotoxicity (DIC) through regulating the gut-microbiota-heart (GMH) axis. The role of gut microbiota and its metabolites in DIC, however, is largely unelucidated. Our review will focus on the potential mechanism between gut microbiota dysbiosis and DIC, so as to provide novel insights into the pathophysiology of DIC. Furthermore, we summarize the underlying interventions of microbial-targeted therapeutics in DIC, encompassing dietary interventions, fecal microbiota transplantation (FMT), probiotics, antibiotics, and natural phytochemicals. Given the emergence of microbial investigation in DIC, finally we aim to point out a novel direction for future research and clinical intervention of DIC, which may be helpful for the DIC patients.

Enterococcus faecalis: implications for host health

The microbiota represents a crucial area of research in maintaining human health due to its potential for uncovering novel biomarkers, therapies, and molecular mechanisms relevant to population identification and experimental model characterization. Among these microorganisms, Enterococcus faecalis, a Gram-positive bacterium found in the gastrointestinal tract of humans and animals, holds particular significance. Strains of this bacterial species have sparked considerable debate in the literature due to their dual nature; they can either be utilized as probiotics in the food industry or demonstrate resistance to antibiotics, potentially leading to severe illness, disability, and death. Given the diverse characteristics of Enterococcus faecalis strains, this review aims to provide a comprehensive understanding of their impact on various systems within the host, including the immunological, cardiovascular, metabolic, and nervous systems. Furthermore, we summarize the bacterium-host interaction characteristics and molecular effects to highlight their targets, features, and overall impact on microbial communities and host health.

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

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

Rome III Criteria Capture Higher Irritable Bowel Syndrome SNP-Heritability and Highlight a Novel Genetic Link With Cardiovascular Traits

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) shows genetic predisposition, and large-scale genome-wide association studies (GWAS) are emerging, based on heterogeneous disease definitions. We investigated the genetic architecture of IBS defined according to gold standard Rome Criteria.

METHODS

We conducted GWAS meta-analyses of Rome III IBS and its subtypes in 24,735 IBS cases and 77,149 asymptomatic control subjects from 2 independent European cohorts (UK Biobank and Lifelines). Single-nucleotide polymorphism (SNP)-based heritability (h2SNP) and genetic correlations (rg) with other traits were calculated. IBS risk loci were functionally annotated to identify candidate genes. Sensitivity and conditional analyses were conducted to assess impact of confounders. Polygenic risk scores were computed and tested in independent datasets.

RESULTS

Rome III IBS showed significant SNP-heritability (up to 13%) and similar genetic architecture across subtypes, including those with manifestations at the opposite ends of the symptom spectrum (rg = 0.48 between IBS-D and IBS-C). Genetic correlations with other traits highlighted commonalities with family history of heart disease and hypertension, coronary artery disease, and angina pectoris (rg = 0.20-0.45), among others. Four independent GWAS signals (P < 5×10-8) were detected, including 2 novel loci for IBS (rs2035380) and IBS-mixed (rs2048419) that had been previously associated with hypertension and coronary artery disease. Functional annotation of GWAS risk loci revealed genes implicated in circadian rhythm (BMAL1), intestinal barrier (CLDN23), immunomodulation (MFHAS1), and the cyclic adenosine monophosphate pathway (ADCY2). Polygenic risk scores allowed the identification of individuals at increased risk of IBS (odds ratio, 1.34; P = 1.1×10-3).

CONCLUSIONS

Rome III Criteria capture higher SNP-heritability than previously estimated for IBS. The identified link between IBS and cardiovascular traits may contribute to the delineation of alternative therapeutic strategies, warranting further investigation.

Microbiota-derived acetate attenuates neuroinflammation in rostral ventrolateral medulla of spontaneously hypertensive rats

BACKGROUND

Increased neuroinflammation in brain regions regulating sympathetic nerves is associated with hypertension. Emerging evidence from both human and animal studies suggests a link between hypertension and gut microbiota, as well as microbiota-derived metabolites short-chain fatty acids (SCFAs). However, the precise mechanisms underlying this gut-brain axis remain unclear.

METHODS

The levels of microbiota-derived SCFAs in spontaneously hypertensive rats (SHRs) were determined by gas chromatography-mass spectrometry. To observe the effect of acetate on arterial blood pressure (ABP) in rats, sodium acetate was supplemented via drinking water for continuous 7 days. ABP was recorded by radio telemetry. The inflammatory factors, morphology of microglia and astrocytes in rostral ventrolateral medulla (RVLM) were detected. In addition, blood-brain barrier (BBB) permeability, composition and metabolomics of the gut microbiome, and intestinal pathological manifestations were also measured.

RESULTS

The serum acetate levels in SHRs are lower than in normotensive control rats. Supplementation with acetate reduces ABP, inhibits sympathetic nerve activity in SHRs. Furthermore, acetate suppresses RVLM neuroinflammation in SHRs, increases microglia and astrocyte morphologic complexity, decreases BBB permeability, modulates intestinal flora, increases fecal flora metabolites, and inhibits intestinal fibrosis.

CONCLUSIONS

Microbiota-derived acetate exerts antihypertensive effects by modulating microglia and astrocytes and inhibiting neuroinflammation and sympathetic output.