The Gut Microbiome in Hypertension: Recent Advances and Future Perspectives

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.

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.

Reactive oxygen species in hypertension

Hypertension is a leading risk factor for stroke, heart disease and chronic kidney disease. Multiple interacting factors and organ systems increase blood pressure and cause target-organ damage. Among the many molecular elements involved in the development of hypertension are reactive oxygen species (ROS), which influence cellular processes in systems that contribute to blood pressure elevation (such as the cardiovascular, renal, immune and central nervous systems, or the renin-angiotensin-aldosterone system). Dysregulated ROS production (oxidative stress) is a hallmark of hypertension in humans and experimental models. Of the many ROS-generating enzymes, NADPH oxidases are the most important in the development of hypertension. At the cellular level, ROS influence signalling pathways that define cell fate and function. Oxidative stress promotes aberrant redox signalling and cell injury, causing endothelial dysfunction, vascular damage, cardiovascular remodelling, inflammation and renal injury, which are all important in both the causes and consequences of hypertension. ROS scavengers reduce blood pressure in almost all experimental models of hypertension; however, clinical trials of antioxidants have yielded mixed results. In this Review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in hypertension. We focus on cellular sources of ROS, molecular mechanisms of oxidative stress and alterations in redox signalling in organ systems, and their contributions to hypertension.

Anthocyanins as natural bioactives with anti-hypertensive and atherosclerotic potential: Health benefits and recent advances

BACKGROUND

Hypertension is a highly prevalent chronic metabolic illness affecting individuals of all age groups. Furthermore, it is a significant risk factor for the development of atherosclerosis (AS), as a correlation between hypertension and AS has been observed. However, the effective treatments for either of these disorders appear to be uncommon.

METHODS

A systematic search of articles published in PubMed, Web of Science, ScienceDirect, Scopus, and Google Scholar databases over the last decade was performed using the following keywords: hypertension, AS, anthocyanins, antioxidants, gut microbes, health benefits, and bioactivity.

RESULTS

The available research indicates that anthocyanin consumption can achieve antioxidant effects by inducing the activation of intracellular nuclear factor erythroid 2-related factor (Nrf2) and the expression of antioxidant genes. Moreover, previous reports showed that anthocyanins can enhance the human body's ability to fight against inflammation and cancer through the inhibition of inflammatory factors and the regulation of related signaling pathways. They can also protect the blood vessels and nervous system by regulating the production and function of endothelial nitric oxide synthase (eNOS). Gut microorganisms play an important role in various chronic diseases. Our research has also investigated the role of anthocyanins in the metabolism of the gut microbiota, leading to significant breakthroughs. This study not only presents a unique strategy for reducing the risk of cardiovascular diseases (CVDs) without the need for medicine but also provides insights into the development and utilization of intestinal probiotic dietary supplements.

CONCLUSION

In this review, different in vitro and in vivo studies have shown that anthocyanins slow down the onset and progression of hypertension and AS through different mechanisms. In addition, gut microbial metabolites also play a crucial role in diseases through the gut-liver axis.

Retinal Vein Occlusion-Background Knowledge and Foreground Knowledge Prospects-A Review

Thrombosis of retinal veins is one of the most common retinal vascular diseases that may lead to vascular blindness. The latest epidemiological data leave no illusions that the burden on the healthcare system, as impacted by patients with this diagnosis, will increase worldwide. This obliges scientists to search for new therapeutic and diagnostic options. In the 21st century, there has been tremendous progress in retinal imaging techniques, which has facilitated a better understanding of the mechanisms related to the development of retinal vein occlusion (RVO) and its complications, and consequently has enabled the introduction of new treatment methods. Moreover, artificial intelligence (AI) is likely to assist in selecting the best treatment option for patients in the near future. The aim of this comprehensive review is to re-evaluate the old but still relevant data on the RVO and confront them with new studies. The paper will provide a detailed overview of diagnosis, current treatment, prevention, and future therapeutic possibilities regarding RVO, as well as clarifying the mechanism of macular edema in this disease entity.

Association between gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study

Background

To clarify the causal relationship between gut microbiota and diabetic nephropathy (DN), we employed Mendelian randomization (MR). Despite a strong correlation observed, establishing causality is still unclear. By utilizing MR, we aimed to investigate this relationship further and shed light on the potential causal effect of gut microbiota on DN.

Methods

Genetic instrumental variables for gut microbiota were obtained from a GWAS with 18340 participants. DN summary statistics (1032 cases, 451248 controls) were sourced from a separate GWAS. The primary analysis used the inverse-variance weighted (IVW) method. Reverse MR analysis was conducted to explore reverse causation. Rigorous sensitivity analyses were performed to ensure the resilience and reliability of the study's findings.

Results

We found two bacterial traits associated with an increased risk of DN: genus LachnospiraceaeUCG008 (OR: 1.4210; 95% CI: 1.0450, 1.9322; p = 0.0250) and genus Terrisporobacter (OR: 1.9716; 95% CI: 1.2040, 3.2285; p = 0.0070). Additionally, phylum Proteobacteria (OR: 0.4394; 95% CI: 0.2721, 0.7096; p = 0.0008) and genus Dialister (OR: 0.4841; 95% CI: 0.3171, 0.7390; p = 0.0008) were protective against DN. Sensitivity analyses consistently supported these results. In the reverse MR analysis, no statistically significant associations were observed between DN and these four bacterial traits.

Conclusions

Our analyses confirmed a potential causal relationship between certain gut microbiota taxa and the risk of DN. However, additional studies are required to elucidate the underlying mechanisms through which gut microbiota influences the development of DN.

Perspectives on the involvement of the gut microbiota in salt-sensitive hypertension

Salt-sensitivity hypertension (SSH) is an independent predictor of cardiovascular event-related death. Despite the extensiveness of research on hypertension, which covers areas such as the sympathetic nervous system, the renin-angiotensin system, the vascular system, and the immune system, its pathogenesis remains elusive, with sub-optimal blood pressure control in patients. The gut microbiota is an important component of nutritional support and constitutes a barrier in the host. Long-term high salt intake can lead to gut microbiota dysbiosis and cause significant changes in the expression of gut microbiota-related metabolites. Of these metabolites, short chain fatty acids (SCFAs), trimethylamine oxide, amino acids, bile acids, and lipopolysaccharide are essential mediators of microbe-host crosstalk. These metabolites may contribute to the incidence and development of SSH via inflammatory, immune, vascular, and nervous pathways, among others. In addition, recent studies, including those on the histone deacetylase inhibitory mechanism of SCFAs and the blood pressure-decreasing effects of H2S via vascular activation, suggest that several proteins and factors in the classical pathway elicit their effects through multiple non-classical pathways. This review summarizes changes in the gut microbiota and its related metabolites in high-salt environments, as well as corresponding treatment methods for SSH, such as diet management, probiotic and prebiotic use, antibiotic use, and fecal transplantation, to provide new insights and perspectives for understanding SSH pathogenesis and the development of strategies for its treatment.

The role of gut microbiota in the development of salt-sensitive hypertension and the possible preventive effect of exercise

INTRODUCTION

The aim of the present study is to analyze the data indicating an association between high salt intake and the gastrointestinal microbiota in the development of salt-sensitive hypertension in animals and men. It is also, to discuss the preventive effects of exercise on gut-induced hypertension by favorably modifying the composition of gut microbiota.

AREAS COVERED

Salt sensitivity is quite common, accounting for 30%-60% in hypertensive subjects. Recently, a novel cause for salt-sensitive hypertension has been discovered through the action of gut microbiota by the secretion of several hormones and the action of short chain fatty acids (SCFAs). In addition, recent studies indicate that exercise might favorably modify the adverse effects of gut microbiota regarding their effects on BP. To identify the role of gut microbiota on the incidence of hypertension and CVD and the beneficial effect of exercise, a Medline search of the English literature was conducted between 2018 and 2023 and 42 pertinent papers were selected.

EXPERT OPINION

The analysis of data from the selected papers disclosed that the gut microbiota contribute significantly to the development of salt-sensitive hypertension and that exercise modifies their gut composition and ameliorates their adverse effects on BP.

Association of enterolactone with blood pressure and hypertension risk in NHANES

The gut microbiome may affect overall cardiometabolic health. Enterolactone is an enterolignan reflective of dietary lignan intake and gut microbiota composition and diversity that can be measured in the urine. The purpose of this study was to examine the association between urinary enterolactone concentration as a reflection of gut health and blood pressure/risk of hypertension in a large representative sample from the US population. This analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES) collected from January 1999 through December 2010. Variables of interest included participant characteristics (including demographic, anthropometric and social/environmental factors), resting blood pressure and hypertension history, and urinary enterolactone concentration. 10,637 participants (45 years (SE = 0.3), 51.7% (SE = 0.6%) were female) were included in analyses. In multivariable models adjusted for demographic, socioeconomic and behavioral/environmental covariates, each one-unit change in log-transformed increase in enterolactone was associated with a 0.738 point (95% CI: -0.946, -0.529; p<0.001) decrease in systolic blood pressure and a 0.407 point (95% CI: -0.575, -0.239; p<0.001) decrease in diastolic blood pressure. Moreover, in fully adjusted models, each one-unit change in log-transformed enterolactone was associated with 8.2% lower odds of hypertension (OR = 0.918; 95% CI: 0.892, 0.944; p<0.001). Urinary enterolactone, an indicator of gut microbiome health, is inversely associated with blood pressure and hypertension risk in a nationally representative sample of U.S. adults.

Impact of fundamental components of the Mediterranean diet on the microbiota composition in blood pressure regulation

BACKGROUND

The Mediterranean diet (MedDiet) is a widely studied dietary pattern reflecting the culinary traditions of Mediterranean regions. High adherence to MedDiet correlates with reduced blood pressure and lower cardiovascular disease (CVD) incidence and mortality. Furthermore, microbiota, influenced by diet, plays a crucial role in cardiovascular health, and dysbiosis in CVD patients suggests the possible beneficial effects of microbiota modulation on blood pressure. The MedDiet, rich in fiber and polyphenols, shapes a distinct microbiota, associated with higher biodiversity and positive health effects. The review aims to describe how various Mediterranean diet components impact gut microbiota, influencing blood pressure dynamics.

MAIN BODY

The MedDiet promotes gut health and blood pressure regulation through its various components. For instance, whole grains promote a healthy gut microbiota given that they act as substrates leading to the production of short-chain fatty acids (SCFAs) that can modulate the immune response, preserve gut barrier integrity, and regulate energy metabolism. Other components of the MedDiet, including olive oil, fuits, vegetables, red wine, fish, and lean proteins, have also been associated with blood pressure and gut microbiota regulation.

CONCLUSION

The MedDiet is a dietary approach that offers several health benefits in terms of cardiovascular disease management and its associated risk factors, including hypertension. Furthermore, the intake of MedDiet components promote a favorable gut microbiota environment, which, in turn, has been shown that aids in other physiological processes like blood pressure regulation.

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.

The gut microbiome as a modulator of arterial function and age-related arterial dysfunction

The arterial system is integral to the proper function of all other organs and tissues. Arterial function is impaired with aging, and arterial dysfunction contributes to the development of numerous age-related diseases, including cardiovascular diseases. The gut microbiome has emerged as an important regulator of both normal host physiological function and impairments in function with aging. The purpose of this review is to summarize more recently published literature demonstrating the role of the gut microbiome in supporting normal arterial development and function and in modulating arterial dysfunction with aging in the absence of overt disease. The gut microbiome can be altered due to a variety of exposures, including physiological aging processes. We explore mechanisms by which the gut microbiome may contribute to age-related arterial dysfunction, with a focus on changes in various gut microbiome-related compounds in circulation. In addition, we discuss how modulating circulating levels of these compounds may be a viable therapeutic approach for improving artery function with aging. Finally, we identify and discuss various experimental considerations and research gaps/areas of future research.

Microbial influence on blood pressure: unraveling the complex relationship for health insights

Hypertension, a critical global health concern, is characterized by persistent high blood pressure and is a major cause of cardiovascular events. This perspective explores the multifaceted implications of hypertension, its association with cardiovascular diseases, and the emerging role of the gut microbiota. The gut microbiota, a dynamic community in the gastrointestinal tract, plays a pivotal role in hypertension by influencing blood pressure through the generation of antioxidant, anti-inflammatory, and short-chain fatty acids metabolites, and the conversion of nitrates into nitric oxide. Antihypertensive medications interact with the gut microbiota, impacting drug pharmacokinetics and efficacy. Prebiotics and probiotics present promising avenues for hypertension management, with prebiotics modulating blood pressure through lipid and cholesterol modulation, and probiotics exhibiting a general beneficial effect. Personalized choices based on individual factors are crucial for optimizing prebiotic and probiotic interventions. In conclusion, the gut microbiota's intricate influence on blood pressure regulation offers innovative perspectives in hypertension therapeutics, with targeted strategies proving valuable for holistic blood pressure management and health promotion.

P2X7-Mediated Antigen-Independent Activation of CD8+ T Cells Promotes Salt-Sensitive Hypertension

BACKGROUND

CD8+ T cells (CD8Ts) have been implicated in hypertension. However, the specific mechanisms are not fully understood. In this study, we explore the contribution of the P2X7 (purinergic receptor P2X7) receptor to CD8T activation and subsequent promotion of sodium retention in the kidney.

METHODS

We used mouse models of hypertension. Wild type were used as genetic controls, OT1 and Rag2/OT1 mice were utilized to determine antigen dependency, and P2X7-knockout mice were studied to define the role of P2X7 in activating CD8Ts and promoting hypertension. Blood pressure was monitored continuously and kidneys were obtained at different experimental end points. Freshly isolated CD8Ts from mice for activation assays and ATP stimulation. CD8T activation-induced promotion of sodium retention was explored in cocultures of CD8Ts and mouse DCTs.

RESULTS

We found that OT1 and Rag2/OT1 mice, which are nonresponsive to common antigens, still developed hypertension and CD8T-activation in response to deoxycorticosterone acetate/salt treatment, similar to wild-type mice. Further studies identified the P2X7 receptor on CD8Ts as a possible mediator of this antigen-independent activation of CD8Ts in hypertension. Knockout of the P2X7 receptor prevented calcium influx and cytokine production in CD8Ts. This finding was associated with reduced CD8T-DCT stimulation, reversal of excessive salt retention in DCTs, and attenuated development of salt-sensitive hypertension.

CONCLUSIONS

Our findings suggest a novel mechanism by which CD8Ts are activated in hypertension to exacerbate salt retention and infer that the P2X7 receptor on CD8Ts may represent a new therapeutic target to attenuate T-cell-mediated immunopathology in hypertension.

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.

Causal associations between gut microbiota, metabolites and asthma: a two-sample Mendelian randomization study

BACKGROUND

While several traditional observational studies have suggested associations between gut microbiota and asthma, these studies are limited by factors such as participant selection bias, confounders, and reverse causality. Therefore, the causal relationship between gut microbiota and asthma remains uncertain.

METHODS

We performed two-sample bi-directional Mendelian randomization (MR) analysis to investigate the potential causal relationships between gut microbiota and asthma as well as its phenotypes. We also conducted MR analysis to evaluate the causal effect of gut metabolites on asthma. Genetic variants for gut microbiota were obtained from the MiBioGen consortium, GWAS summary statistics for metabolites from the TwinsUK study and KORA study, and GWAS summary statistics for asthma from the FinnGen consortium. The causal associations between gut microbiota, gut metabolites and asthma were examined using inverse variance weighted, maximum likelihood, MR-Egger, weighted median, and weighted model and further validated by MR-Egger intercept test, Cochran's Q test, and "leave-one-out" sensitivity analysis.

RESULTS

We identified nine gut microbes whose genetically predicted relative abundance causally impacted asthma risk. After FDR correction, significant causal relationships were observed for two of these microbes, namely the class Bacilli (OR = 0.84, 95%CI = 0.76-0.94, p = 1.98 × 10-3) and the order Lactobacillales (OR = 0.83, 95%CI = 0.74-0.94, p = 1.92 × 10-3). Additionally, in a reverse MR analysis, we observed a causal effect of genetically predicted asthma risk on the abundance of nine gut microbes, but these associations were no longer significant after FDR correction. No significant causal effect of gut metabolites was found on asthma.

CONCLUSIONS

Our study provides insights into the development mechanism of microbiota-mediated asthma, as well as into the prevention and treatment of asthma through targeting specific gut microbiota.

Pediococcus acidilactici reduces tau pathology and ameliorates behavioral deficits in models of neurodegenerative disorders

BACKGROUND

Alzheimer's disease (AD), affecting many elders worldwide, is characterized by A-beta and tau-related cognitive decline. Accumulating evidence suggests that brain iron accumulation is an important characteristic of AD. However, the function and mechanism of the iron-mediated gut-brain axis on AD is still unclear.

METHODS

A Caenorhabditis elegans model with tau-overexpression and a high-Fe diet mouse model of cognitive impairment was used for probiotic function evaluation. With the use of qPCR, and immunoblotting, the probiotic regulated differential expression of AD markers and iron related transporting genes was determined. Colorimetric kits, IHC staining, and immunofluorescence have been performed to explore the probiotic mechanism on the development of gut-brain links and brain iron accumulation.

RESULTS

In the present study, a high-Fe diet mouse model was used for evaluation in which cognitive impairment, higher A-beta, tau and phosphorylated (p)-tau expression, and dysfunctional phosphate distribution were observed. Considering the close crosstalk between intestine and brain, probiotics were then employed to delay the process of cognitive impairment in the HFe mouse model. Pediococcus acidilactici (PA), but not Bacillus subtilis (BN) administration in HFe-fed mice reduced brain iron accumulation, enhanced global alkaline phosphatase (AP) activity, accelerated dephosphorylation, lowered phosphate levels and increased brain urate production. In addition, because PA regulated cognitive behavior in HFe fed mice, we used the transgenic Caenorhabditis elegans with over-expressed human p-tau for model, and then PA fed worms became more active and longer lived than E.coli fed worms, as well as p-tau was down-regulated. These results suggest that brain iron accumulation influences AD risk proteins and various metabolites. Furthermore, PA was shown to reverse tau-induced pathogenesis via iron transporters and AP-urate interaction.

CONCLUSIONS

PA administration studies demonstrate that PA is an important mediator of tau protein reduction, p-tau expression and neurodegenerative behavior both in Caenorhabditis elegans and iron-overload mice. Finally, our results provide candidates for AP modulation strategies as preventive tools for promoting brain health. Video Abstract.

Exploring a novel therapeutic strategy: the interplay between gut microbiota and high-fat diet in the pathogenesis of metabolic disorders

In the past two decades, the rapid increase in the incidence of metabolic diseases, including obesity, diabetes, dyslipidemia, non-alcoholic fatty liver disease, hypertension, and hyperuricemia, has been attributed to high-fat diets (HFD) and decreased physical activity levels. Although the phenotypes and pathologies of these metabolic diseases vary, patients with these diseases exhibit disease-specific alterations in the composition and function of their gut microbiota. Studies in germ-free mice have shown that both HFD and gut microbiota can promote the development of metabolic diseases, and HFD can disrupt the balance of gut microbiota. Therefore, investigating the interaction between gut microbiota and HFD in the pathogenesis of metabolic diseases is crucial for identifying novel therapeutic strategies for these diseases. This review takes HFD as the starting point, providing a detailed analysis of the pivotal role of HFD in the development of metabolic disorders. It comprehensively elucidates the impact of HFD on the balance of intestinal microbiota, analyzes the mechanisms underlying gut microbiota dysbiosis leading to metabolic disruptions, and explores the associated genetic factors. Finally, the potential of targeting the gut microbiota as a means to address metabolic disturbances induced by HFD is discussed. In summary, this review offers theoretical support and proposes new research avenues for investigating the role of nutrition-related factors in the pathogenesis of metabolic disorders in the organism.

Exploring the gut mycobiome: differential composition and clinical associations in hypertension, chronic kidney disease, and their comorbidity

Background

Hypertension (HTN) and chronic kidney disease (CKD) pose significant global health challenges and often coexist, amplifying cardiovascular risks. Recent attention has turned to the gut mycobiome as a potential factor in their pathophysiology. Our study sought to examine the gut fungal profile in individuals with HTN, CKD, and the concurrent HTN+CKD condition, investigating its connections with serum cytokines, renal function, and blood pressure.

Methods and materials

We investigated three distinct participant groups: a cohort of 50 healthy controls (HC), 50 individuals diagnosed with HTN-only, and 50 participants suffering from both HTN and CKD (HTN+CKD). To facilitate our research, we gathered fecal and blood samples and conducted a comprehensive analysis of serum cytokines. Moreover, fungal DNA extraction was conducted with meticulous care, followed by sequencing of the Internal Transcribed Spacer (ITS) region.

Results

HTN+CKD patients displayed distinctive fungal composition with increased richness and diversity compared to controls. In contrast, HTN-only patients exhibited minimal fungal differences. Specific fungal genera were notably altered in HTN+CKD patients, characterized by increased Apiotrichum and Saccharomyces levels and reduced Candida abundance. Our correlation analyses revealed significant associations between fungal genera and serum cytokines. Moreover, certain fungal taxa, such as Apiotrichum and Saccharomyces, exhibited positive correlations with renal function, while others, including Septoria, Nakaseomyces, and Saccharomyces, were linked to blood pressure, particularly diastolic pressure.

Conclusion

Gut mycobiome dysbiosis in individuals with comorbid HTN and CKD differs significantly from that observed in HTN-only and healthy controls. The interactions between serum cytokines, renal function, and blood pressure emphasize the potential impact of the fungal microbiome on these conditions. Additional research is required to clarify the underlying mechanisms and identify therapeutic opportunities associated with mycobiome dysbiosis in HTN and CKD.

Single cell transcriptome analyses reveal the roles of B cells in fructose-induced hypertension

Rationale

While the immune system plays a crucial role in the development of hypertension, the specific contributions of distinct immune cell populations remain incompletely understood. The emergence of single-cell RNA-sequencing (scRNA-seq) technology enables us to analyze the transcriptomes of individual immune cells and to assess the significance of each immune cell type in hypertension development.

Objective

We aimed to investigate the hypothesis that B cells play a crucial role in the development of fructose-induced hypertension.

Methods and Results

Eight-week-old Dahl salt-sensitive (SS) male rats were divided into two groups and given either tap water (TW) or a 20% fructose solution (HFS) for 4 weeks. Systolic blood pressure was measured using the tail-cuff method. ScRNA-seq analysis was performed on lamina propria cells (LPs) and peripheral blood mononuclear cells (PBMCs) obtained from SS rats subjected to either TW or HFS. The HFS treatment induced hypertension in the SS rats. The analysis revealed 27 clusters in LPs and 28 clusters in PBMCs, allowing for the identification and characterization of various immune cell types within each cluster. Specifically, B cells and follicular helper T (Tfh) cells were prominent in LPs, while B cells and M1 macrophages dominated PBMCs in the HFS group. Moreover, the HFS treatment triggered an increase in the number of B cells in both LPs and PBMCs, accompanied by activation of the interferon pathway.

Conclusions

The significant involvement of B cells in intestinal and PBMC responses indicates their pivotal contribution to the development of hypertension. This finding suggests that targeting B cells could be a potential strategy to mitigate high blood pressure in fructose-induced hypertension. Moreover, the simultaneous increase in follicular B cells and Tfh cells in LPs, along with the upregulation of interferon pathway genes in B cells, underscores a potential autoimmune factor contributing to the pathogenesis of fructose-induced hypertension in the intestine.

Microbiome and Retinal Vascular Diseases

The gut microbiome consists of more than a thousand different microbes and their associated genes and microbial metabolites. It influences various host metabolic pathways and is therefore important for homeostasis. In recent years, its influence on health and disease has been extensively researched. Dysbiosis, or imbalance in the gut microbiome, is associated with several diseases. Consequent chronic inflammation may lead to or promote inflammatory bowel disease, obesity, diabetes mellitus, atherosclerosis, alcoholic and non-alcoholic liver disease, cirrhosis, hepatocellular carcinoma, and other diseases. The pathogenesis of the three most common retinal vascular diseases, diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion, may also be influenced by an altered microbiome and associated risk factors such as diabetes mellitus, atherosclerosis, hypertension, and obesity. Direct cause-effect relationships remain less well understood. A potential prevention or treatment modality for these diseases could be targeting and modulating the individual's gut microbiome.

Trend of blood pressure changes among children from 2012 to 2022: findings from student health surveillance in Eastern China

OBJECTIVES

The primary objective of this study is to examine the secular trends in blood pressure levels from 2012 to 2022 in eastern China. Additionally, to compare two standards [International Blood Pressure Reference for Children and Adolescents (ICBP) and the National Blood Pressure Reference for Chinese Han Children and Adolescents (CCBP)], we calculate the 95th percentile of blood pressure levels for students in developed regions (ECCBP). Secondly, the study aims to investigate potential contributors to elevated blood pressure, including sex, age, behaviors, and mental health. Lastly, the study seeks to estimate the total population aged 7-18 years with elevated blood pressure in Eastern China based on three references.

METHODS

The data used in this study were obtained from the Student Health Surveillance program in Jiangsu Province, which has been collecting data since 2012. Trained project members, skilled nurses, and doctors measured anthropometric variables. Additionally, online student questionnaires were administered in 2017, 2019, and 2021 to collect personal information behavior patterns, and mental health.

RESULTS

The study examined blood pressure changes in 123 013 children and adolescents in Eastern China from 2012 to 2022. Significant increases were observed in systolic blood pressure (SBP) and pulse pressure difference. Prevalence of elevated blood pressure followed a similar trend with ECCBP and CCBP, ranging from 17.2%/16.3% (2012-2015) to 11.6%/14.6% (2020-2022). Notably, BP with ICBP showed a significant increase in both prevalence and population, from 12.6% [6 713 679, 95% confidence interval (CI): 6 708 931 to 6 718 427] to 14.5% (7 004 208, 95% CI: 6 999 411 to 7 009 004). The study further emphasizes the significant impact of various risk factors on elevated blood pressure among children and adolescents, particularly the detrimental effect of depression on blood pressure, with the odds ratios (OR) in 2021 being 1.310 (95% CI, 1.290-1.330) for ECCBP, 1.239 (95% CI, 1.223-1.255) for CCBP, and 1.189 (95% CI, 1.176-1.202) for ICBP.

CONCLUSION

The study revealed significant changes in the population and prevalence of elevated blood pressure in Eastern China from 2012 to 2022. The findings indicate a decline in the prevalence of elevated blood pressure (referred to as CCBP or ECCBP), while highlighting an increasing trend in elevated blood pressure (referred to as ICBP). Untreated high blood pressure can lead to serious cardiovascular diseases in adulthood, underscoring the importance of early prevention and management, particularly through nonpharmacological methods and regular monitoring for students in Eastern China. Raising awareness among educators, parents, and healthcare providers about the association between mental health and elevated blood pressure is essential.

Overview of microbes in hypertension

High blood pressure (BP), known as hypertension, is a major contributing factor to the development of cardiovascular disease. The development and pathogenesis of hypertension involve a wide array of factors including genetics, environment, hormones, hemodynamics, and inflammation. There is a significantly positive association between higher levels of colonization by Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola (etiologic bacterial burden) below the gum line, and the presence of hypertension. The use of antibiotics during pregnancy, which is likely indicative of bacterial infections severe enough to require antibiotic treatment, is associated with a slight increase in average arterial BP. Cytomegalovirus infection is a risk factor for heightened arterial BP and acts as a co-factor in the development of aortic atherosclerosis. The relationship between hypertension and coronavirus disease 2019 involves endothelial dysfunction and dysregulation of the renin-angiotensin system. The effects of gut microbiota on BP, whether beneficial or harmful, are influenced by multiple factors including genetics, epigenetics, lifestyle choices, and antibiotic usage. These variables collectively contribute to overall BP levels and the control of hypertension. Several reports have examined the BP levels of patients infected with the Zika virus. In regions with a high incidence of nasopharyngeal carcinoma, hypertension has been linked to a higher risk of Epstein-Barr virus reactivation. Also, a potential causal link has been found between malaria and elevated BP. Also, the elevated prevalence of hypertension among dengue patients during their initial visit suggests that relying solely on BP measurements to predict severe infection may not be clinically reliable.

Exploring the gut microbiota: lifestyle choices, disease associations, and personal genomics

The gut microbiota is a rich and dynamic ecosystem that actively interacts with the human body, playing a significant role in the state of health and disease of the host. Diet, exercise, mental health, and other factors have exhibited the ability to influence the gut bacterial composition, leading to changes that can prevent and improve, or favor and worsen, both intestinal and extra-intestinal conditions. Altered gut microbial states, or 'dysbiosis', associated with conditions and diseases are often characterized by shifts in bacterial abundance and diversity, including an impaired Firmicutes to Bacteroidetes ratio. By understanding the effect of lifestyle on the gut microbiota, personalized advice can be generated to suit each individual profile and foster the adoption of lifestyle changes that can both prevent and ameliorate dysbiosis. The delivery of effective and reliable advice, however, depends not only on the available research and current understanding of the topic, but also on the methods used to assess individuals and to discover the associations, which can introduce bias at multiple stages. The aim of this review is to summarize how human gut microbial variability is defined and what lifestyle choices and diseases have shown association with gut bacterial composition. Furthermore, popular methods to investigate the human gut microbiota are outlined, with a focus on the possible bias caused by the lack of use of standardized methods. Finally, an overview of the current state of personalized advice based on gut microbiota testing is presented, underlining its power and limitations.

Impact of gut microbiome on the renin-aldosterone system: Shika-machi Super Preventive Health Examination results

The renin-angiotensin-aldosterone system (RAAS) is a regulatory mechanism of the endocrine system and is associated with various diseases, including hypertension and renal and cardiovascular diseases. The gut microbiota (GM) have been associated with various diseases, mainly in animal models. However, to our knowledge, no studies have examined the relationship between the RAAS and GM in humans. The present study aimed to assess the association between the systemic RAAS and GM genera and their causal relationships. The study participants were 377 members of the general population aged 40 years or older in Shika-machi, Japan. Plasma renin activity (PRA), plasma aldosterone concentration (PAC), aldosterone-renin ratio (ARR), and GM composition were analyzed using the 16S rRNA method. The participants were divided into high and low groups according to the PRA, PAC, and ARR values. U-tests, one-way analysis of covariance, and linear discriminant analysis of effect size were used to identify the important bacterial genera between the two groups, and binary classification modeling using Random Forest was used to calculate the importance of the features. The results showed that Blautia, Bacteroides, Akkermansia, and Bifidobacterium were associated with the RAAS parameters. Causal inference analysis using the linear non-Gaussian acyclic model revealed a causal effect of Blautia on PAC via SBP. These results strengthen the association between the systemic RAAS and GM in humans, and interventions targeting the GM may provide new preventive measures and treatments for hypertension and renal disease.

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.

Metagenomic characterization of the microbiomes in five different body habitats of otherwise healthy individuals with periodontal disease

Introduction

Recent studies have proposed several plausible mechanisms supporting the association between periodontal disease and systemic disease. However, characterizing the microbial communities in individuals with periodontal disease before onset of other diseases is an important first step in determining how the altered microbial state contributes to disease progression. This study established microbiome profiles for five body habitats of carefully selected, otherwise healthy individuals with periodontal disease.

Methods

Blood, oral (buccal mucosa, dental plaque, and saliva), and stool samples were collected from ten healthy subjects with periodontal disease. Using 16S rRNA metagenomics, the taxonomic and functional compositions of microbiomes were investigated.

Results

The most predominant phylum in blood and stool was Bacillota. Pseudomonadota accounted for the largest proportion of microbes in the buccal mucosa and saliva, whereas Bacteroidota were the most prevalent in dental plaque. Differential abundance analysis revealed that 12 phyla and 139 genera were differentially abundant between body habitats. Comparison of alpha diversity showed that the blood microbiome has the most diverse community close to neither oral nor stool microbiomes. We also predicted the functional configurations of the microbiome in otherwise healthy subjects with periodontal disease. Principal coordinate analysis based on functional abundance revealed distinct clustering of the microbial communities between different body habitats, as also observed for taxonomic abundance. In addition, 13 functional pathways, including lipopolysaccharide biosynthesis, glutathione metabolism, and proteasome, showed differential expression between habitats.

Discussion

Our results offer insight into the effects of the microbiome on systemic health and disease in people with periodontal disease.

Gut microbiome profile of Chinese hypertension patients with and without type 2 diabetes mellitus

BACKGROUND

The coexistence of hypertension and type 2 diabetes mellitus (T2DM) may largely increase the risk for cardiovascular disease. However, there is no clear consensus on the association between hypertension and the risk of diabetes. Gut microbiota plays important roles in the development of hypertension and T2DM, but whether there is difference between hypertension patients with or without T2DM has not been explored yet.

METHODS

We recruited 101 hypertension patients in this study (72 patients without T2DM named HT group and 29 patients with T2DM named HT-T2DM group). Their blood samples were collected for testing clinical characteristics and fecal samples were tested for bacterial DNA using 16 S ribosomal RNA gene sequencing targeting the V3 and V4 region. The data of 40 samples were downloaded from project PRJNA815750 as health control (HC group) in this study. The community composition and structure of the microbiome, taxonomic difference, co-occurrence network and functional enrichment were analyzed by alpha/beta diversity, LEfSe, Fruchterman Reingold's algorithm and PICRUSt2 functional analysis, respectively.

RESULTS

Alpha and beta diversity analysis showed significant differences in microbial community richness and composition among the three groups. The HC group had a significantly higher Simpson index and a distinct microbiota community compared to the HT and HT-T2DM groups, as demonstrated by significant differences in unweighted and weighted UniFrac distances. The LEfSe analysis identified specific taxa that had significantly different abundance among the groups, such as Bacteroides uniformis, Blautia wexlerae, Alistipes putredinis, and Prevotella stercorea in the HC group, Prevotella copri and Phascolarctobacterium faecium in the HT group, and Klebsiella pneumoniae in the HT-T2DM group. Co-occurrence network analysis indicates that Prevotella copri, Mediterraneibacter gnavus, Alistipes onderdonkii and some unidentified species act as key nodes in the network. Differentially functional pathway identified by PICRUSt2 were concentrated in nutrition and energy metabolism, as well as the biosynthesis of other secondary metabolites.

CONCLUSIONS

Our study found significant differences in microbial community richness, composition, and function among the healthy controls, hypertension patients with and without T2DM. Some specific taxa may explain this difference and serve as potential therapeutic targets for hypertension, T2DM, and their coexistence.

Probiotics and Prebiotics in Cardiovascular Diseases

This Special Issue, titled "Probiotics and Prebiotics in Cardiovascular Diseases", encompasses two comprehensive review articles examining the potential of gut-microbiota-targeted reprogramming interventions designed to prevent the onset and progression of cardiovascular diseases [...].

Association of the human gut microbiota with vascular stiffness

Gut microbiota metabolites have been mechanistically linked to inflammatory pathway activation and atherosclerosis, which are major causes of vascular stiffness (VS). Aiming to investigate if the gut microbiome might be involved in VS development, we performed a cross-sectional study (n = 3,087), nested within the population-based European Prospective Investigations into Cancer and Nutrition (EPIC) Potsdam. We investigated the correlation of the gut microbiota (alpha diversity and taxa abundance) with 3 vascular stiffness measures: carotid-femoral (PWV), aortic augmentation index (AIX) and ankle-brachial index (ABI). Shannon index was not significantly associated with VS but the number of observed Amplicon Sequence Variants (ASV) was positively associated with PWV and AIX. We found a total of 19 ASVs significantly associated with at least one VS measure in multivariable-adjusted models. One ASV (classified as Sutterella wadsworthensis) was associated with 2 VS measures, AIX (- 0.11 ± 0.04) and PWV (-0.14 ± 0.03). Other examples of ASVs associated with VS were Collinsella aerofaciens, previously reported to be affected by diet and Bacteroides uniformis, commercially available as probiotics. In conclusion, our study suggests a potential role of individual components of the gut microbiota in the aetiology of VS.

Alterations of gut microbiota are associated with blood pressure: a cross-sectional clinical trial in Northwestern China

BACKGROUND

The human gut microbiota (GM) is involved in the pathogenesis of hypertension (HTN), and could be affected by various factors, including sex and geography. However, available data directly linking GM to HTN based on sex differences are limited.

METHODS

This study investigated the GM characteristics in HTN subjects in Northwestern China, and evaluate the associations of GM with blood pressure levels based on sex differences. A total of 87 HTN subjects and 45 controls were recruited with demographic and clinical characteristics documented. Fecal samples were collected for 16S rRNA gene sequencing and metagenomic sequencing.

RESULTS

GM diversity was observed higher in females compared to males, and principal coordinate analysis showed an obvious segregation of females and males. Four predominant phyla of fecal GM included Firmicutes, Bacteroidetes, Actinobacteria and Proteobacteria. LEfSe analysis indicated that phylum unidentified_Bacteria was enriched in HTN females, while Leuconostocaceae, Weissella and Weissella_cibaria were enriched in control females (P < 0.05). Functionally, ROC analysis revealed that Cellular Processes (0.796, 95% CI 0.620 ~ 0.916), Human Diseases (0.773, 95% CI 0.595 ~ 0.900), Signal transduction (0.806, 95% CI 0.631 ~ 0.922) and Two-component system (0.806, 95% CI 0.631 ~ 0.922) could differentiate HTN females as effective functional classifiers, which were also positively correlated with systolic blood pressure levels.

CONCLUSIONS

This work provides evidence of fecal GM characteristics in HTN females and males in a northwestern Chinese population, further supporting the notion that GM dysbiosis may participate in the pathogenesis of HTN, and the role of sex differences should be considered. Trial registration Chinese Clinical Trial Registry, ChiCTR1800019191. Registered 30 October 2018 - Retrospectively registered, http://www.chictr.org.cn/ .

Gut Microbiota and Microbial Metabolism in Early Risk of Cardiometabolic Disease

Cardiometabolic disease comprises cardiovascular and metabolic dysfunction and underlies the leading causes of morbidity and mortality, both within the United States and worldwide. Commensal microbiota are implicated in the development of cardiometabolic disease. Evidence suggests that the microbiome is relatively variable during infancy and early childhood, becoming more fixed in later childhood and adulthood. Effects of microbiota, both during early development, and in later life, may induce changes in host metabolism that modulate risk mechanisms and predispose toward the development of cardiometabolic disease. In this review, we summarize the factors that influence gut microbiome composition and function during early life and explore how changes in microbiota and microbial metabolism influence host metabolism and cardiometabolic risk throughout life. We highlight limitations in current methodology and approaches and outline state-of-the-art advances, which are improving research and building toward refined diagnosis and treatment options in microbiome-targeted therapies.

Effects of vitamin B12 deficiency on risk and outcome of ischemic stroke

Ischemic stroke is the most prevalent form of stroke and has a high incidence in older adults, characterized by high morbidity, mortality, disability, and recurrence rate. Vitamin B₁₂ deficiency is prevalent in the elderly and has been reported to be associated with ischemic stroke. The mechanisms maybe include the disorder of methylation metabolism, accumulation of toxic metabolites, immune dysfunction, affecting gut microbial composition and gut-brain immune homeostasis, and toxic stress responses to the brain. Vitamin B₁₂ deficiency may lead to cerebral artery atherosclerosis, change myelination, influence the metabolism and transmission between nerve tissue, and ultimately causes the occurrence and development of ischemic stroke. This paper reviews the correlation between vitamin B₁₂ deficiency and ischemic stroke, looking forward to improving clinicians' understanding and providing new therapeutic directions for ischemic stroke.

Could Gut Microbiota Composition Be a Useful Indicator of a Long-Term Dietary Pattern?

Despite the known effects of diet on gut microbiota composition, not many studies have evaluated the relationship between distinct dietary patterns and gut microbiota. The aim of our study was to determine whether gut microbiota composition could be a useful indicator of a long-term dietary pattern. We collected data from 89 subjects adhering to omnivorous, vegetarian, vegan, and low-carbohydrate, high-fat diet that were equally distributed between groups and homogenous by age, gender, and BMI. Gut microbiota composition was analyzed with a metabarcoding approach using V4 hypervariable region of the 16S rRNA gene. K-means clustering of gut microbiota at the genus level was performed and the nearest neighbor classifier was applied to predict microbiota clustering classes. Our results suggest that gut microbiota composition at the genus level is not a useful indicator of a subject's dietary pattern, with the exception of a vegan diet that is represented by a high abundance of Prevotella 9. Based on our model, a combination of 26 variables (anthropometric measurements, serum biomarkers, lifestyle factors, gastrointestinal symptoms, psychological factors, specific nutrients intake) is more important to predict an individual's microbiota composition cluster, with 91% accuracy, than the dietary intake alone. Our findings could serve to develop strategies to educate individuals about changes of some modifiable lifestyle factors, aiming to classify them into clusters with favorable health markers, independent of their dietary pattern.

A cross-sectional study identifying disparities in serum metabolic profiles among hypertensive patients with ISH, IDH and SDH subtypes

Background

It has been well acknowledged that disordered intestinal microflora and their fermented products play crucial role during the development of hypertension (HTN). Aberrant profiles of fecal bacteria have been documented in subjects with isolated systolic HTN (ISH) and isolated diastolic HTN (IDH) previously. Nevertheless, evidence regarding the association of metabolic products in the bloodstream with ISH, IDH and combined systolic and diastolic HTN (SDH) remains scarce.

Methods

We performed a cross-sectional study and conducted untargeted liquid chromatography-mass spectrometry (LC/MS) analysis on serum samples of 119 participants, including 13 subjects with normotension (SBP < 120/DBP < 80 mm Hg), 11 individuals with ISH (SBP ≥ 130/DBP < 80 mm Hg), 27 patients with IDH (SBP < 130/DBP ≥ 80 mm Hg), and 68 SDH patients (SBP ≥ 130, DBP ≥ 80 mm Hg).

Results

Here, the results showed clearly separated clusters in PLS-DA and OPLS-DA score plots for patients suffering from ISH, IDH and SDH when compared with normotension controls. The ISH group was characterized by elevated levels of 3,5-tetradecadien carnitine and notable reduction of maleic acid. While IDH patients were enriched with metabolites in L-lactic acid and depleted in citric acid. Stearoylcarnitine was identified to be specifically enriched in SDH group. The differentially abundant metabolites between ISH and controls were involved in tyrosine metabolism pathways, and in biosynthesis of phenylalanine for those between SDH and controls. Potential linkages between the gut microbial and serum metabolic signatures were detected within ISH, IDH and SDH groups. Furthermore, we found the association of discriminatory metabolites with the characteristics of patients.

Conclusion

Our findings demonstrate disparate blood metabolomics signatures across ISH, IDH and SDH, with differentially enriched metabolites and potential functional pathways identified, reveal the underlying microbiome and metabolome network in HTN subtypes, and provide potential targets for disease classification and therapeutic strategy in clinical practice.

Gut microbiota dependant trimethylamine N-oxide and hypertension

The human gut microbiota environment is constantly changing and some specific changes influence the host's metabolic, immune, and neuroendocrine functions. Emerging evidence of the gut microbiota's role in the development of cardiovascular disease (CVD) including hypertension is remarkable. There is evidence showing that alterations in the gut microbiota and especially the gut-dependant metabolite trimethylamine N-oxide is associated with hypertension. However, there is a scarcity of literature addressing the role of trimethylamine N-oxide in hypertension pathogenesis. In this review, we discuss the impact of the gut microbiota and gut microbiota dependant trimethylamine N-oxide in the pathogenesis of hypertension. We present evidence from both human and animal studies and further discuss new insights relating to potential therapies for managing hypertension by altering the gut microbiota.

Chai-Gui Decoction and its representative components ameliorate spontaneous hypertension rats by modulating lipid metabolism and gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Hypertension coincides with the category of "vertigo" and/or "headache" on the basis clinical manifestations and traditional Chinese medicine (TCM) theory. Chai-Gui Decoction (CGD), which is in usage for relieving "vertigo" and/or "headache", had been demonstrated to be useful in ameliorating hypertension.

AIM OF STUDY

This study was planned to investigate the mechanism of CGD and its components in hypertension by using spontaneous hypertension rat (SHR).

MATERIALS AND METHODS

CGD extract and its classification component samples (compounds in plasma, CP; compounds in gut, CG; compounds in plasma and gut, CPG) were prepared for animal experiment. SHR rats were induced with CGD extract (3 g/kg/d BW, 5 g/kg/d BW, 15 g/kg/d BW) and CGD-component classes (CP = 19.501 mg/kg/d, CG = 5.240 mg/kg/d, CPG = 24.741 mg/kg/d) for 4 weeks. Blood pressure (BP) and indexes of renin-angiotensin-aldosterone system (RAAS system) were measured. Histopathology was carried out to assess the efficacy of CGD and its components on aorta tissues. Untargeted metabolomics of lipid from rat serum samples were applied by Ultra-High performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and chemometric analysis to explore the relationship between metabolic pathways and hypertension. 16S rRNA gene sequencing of rat colon content and bioinformatics analysis were used to characterize the effects of CGD and its components on the gut microbiota composition of SHR rats.

RESULTS

CGD and its component mixtures showed antihypertensive effect on SHR rats, decreased the blood pressure and reduced the aortic wall thickness in SHR rats. CGD and its component mixtures could improve the RAAS in SHR rats, including increase the percentage of angiotensin 1-7 (Ang 1-7), decrease the percentage of angiotensin II (Ang II), and decrease the Ang Ⅱ/Ang 1-7 ratio. CGD and its component mixtures could regulate the metabolome in SHR rats, mainly as decreasing the higher serum levels of Lysophosphatidylcholine (LPC) 16: 0, LPC 20: 4, and LPC 22: 6. In addition, bacteria from family S24-7 were negatively correlated with levels of LPE 16:0, LPE 18:0, LPE 18:1, and LPE 18:2.

CONCLUSION

CGD and its component mixtures exhibited antihypertensive effect on SHR rats. The underlying mechanism could be related to modulation on RAAS, LPC metabolism and the bacterial abundance of family S24-7 in gut.

Engineered probiotics Clostridium butyricum-pMTL007-GLP-1 improves blood pressure via producing GLP-1 and modulating gut microbiota in spontaneous hypertension rat models

Hypertension is a significant risk factor of cardiovascular diseases (CVDs) with high prevalence worldwide, the current treatment has multiple adverse effects and requires continuous administration. The glucagon-like peptide-1 receptor (GLP-1R) agonists have shown great potential in treating diabetes mellitus, neurodegenerative diseases, obesity and hypertension. Butyric acid is a potential target in treating hypertension. Yet, the application of GLP-1 analogue and butyric acid in reducing blood pressure and reversing ventricular hypertrophy remains untapped. In this study, we combined the therapeutic capability of GLP-1 and butyric acid by transforming Clostridium butyricum (CB) with recombinant plasmid pMTL007 encoded with hGLP gene to construct the engineered probiotics Clostridium butyricum-pMTL007-GLP-1 (CB-GLP-1). We used spontaneous hypertensive rat (SHR) models to evaluate the positive effect of this strain in treating hypertension. The results revealed that the intragastric administration of CB-GLP-1 had markedly reduced blood pressure and improved cardiac marker ACE2, AT2R, AT1R, ANP, BNP, β-MHC, α-SMA and activating AMPK/mTOR/p70S6K/4EBP1 signalling pathway. The high-throughput sequencing further demonstrated that CB-GLP-1 treatments significantly improved the dysbiosis in the SHR rats via downregulating the relative abundance of Porphyromonadaceae at the family level and upregulating Lactobacillus at the genus level. Hence, we concluded that the CB-GLP-1 greatly improves blood pressure and cardiomegaly by restoring the gut microbiome and reducing ventricular hypertrophy in rat models. This is the first time using engineered CB in treating hypertension, which provides a new idea for the clinical treatment of hypertension.

Heart development and regeneration-a multi-organ effort

Development of the heart, from early morphogenesis to functional maturation, as well as maintenance of its homeostasis are tasks requiring collaborative efforts of cardiac tissue and different extra-cardiac organ systems. The brain, lymphoid organs, and gut are among the interaction partners that can communicate with the heart through a wide array of paracrine signals acting at local or systemic level. Disturbance of cardiac homeostasis following ischemic injury also needs immediate response from these distant organs. Our hearts replace dead muscles with non-contractile fibrotic scars. We have learned from animal models capable of scarless repair that regenerative capability of the heart does not depend only on competency of the myocardium and cardiac-intrinsic factors but also on long-range molecular signals originating in other parts of the body. Here, we provide an overview of inter-organ signals that take part in development and regeneration of the heart. We highlight recent findings and remaining questions. Finally, we discuss the potential of inter-organ modulatory approaches for possible therapeutic use.

Gut microbiota and COVID-19: A systematic review

Background and Aims

Alteration in humans' gut microbiota was reported in patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The gut and upper respiratory tract (URT) microbiota harbor a dynamic and complex population of microorganisms and have strong interaction with host immune system homeostasis. However, our knowledge about microbiota and its association with SARS-CoV-2 is still limited. We aimed to systematically review the effects of gut microbiota on the SARS-CoV-2 infection and its severity and the impact that SARS-CoV-2 could have on the gut microbiota.

Methods

We searched the keywords in the online databases of Web of Science, Scopus, PubMed, and Cochrane on December 31, 2021. After duplicate removal, we performed the screening process in two stages; title/abstract and then full-text screening. The data of the eligible studies were extracted into a pre-designed word table. This study adhered to the PRISMA checklist and Newcastle-Ottawa Scale Bias Assessment tool.

Results

Sixty-three publications were included in this review. Our study shows that among COVID-19 patients, particularly moderate to severe cases, the gut and lung microbiota was different compared to healthy individuals. In addition, the severity, and viral load of COVID-19 disease would probably also be influenced by the gut, and lung microbiota's composition.

Conclusion

Our study concludes that there was a significant difference in the composition of the URT, and gut microbiota in COVID-19 patients compared to the general healthy individuals, with an increase in opportunistic pathogens. Further, research is needed to investigate the probable bidirectional association of COVID-19 and human microbiome.

Protection effect of gut microbiota composition and acetate absorption against hypertension-induced damages on the longevity population in Guangxi, China

Introduction

Recent evidence supports a role for the gut microbe-metabolites in longevity. However, the phenomenon of hypertension is more common in the longevity area and whether hypertension is associated with longevity remains unclear. Here, we hypothesize that the levels of gut microbiota, SCFAs, and urine metabolites were different between hypertension elderly and hypertension longevity.

Methods

We recruited 46 elderly volunteers from Donglan County, Guangxi, and 32 were selected and included in the experiment. The subjects with hypertension were divided into two groups according to age, Hypertension Elderly (HTE, aged 70.5 ± 8.59, n = 19) and Hypertension Longevity (HTL, aged 100 ± 5.72, n = 13). The gut microbiota, SCFAs, and urine metabolites were determined by three-generation 16S rRNA full-length sequencing, GC-MS, and ¹H-NMR, respectively.

Results

Compared with the HTL group, the HTE group had higher levels of hypertension-related genera Klebsiella and Streptococcus, while having lower levels of the SCFA-producing genera Bacteroides, Faecalibacterium, and Alistipes. Based on LEFse analysis, Klebsiella pneumoniae, Lactobacillus gasseri, Streptococcus salivarius, Ruminococcus, Actinomyces, Rikenellaceae, f_Saccharimonadaceae, Clostridium perfringens, and Bacteroids, Faecalibacterium prausnitzii, Parabacteroides, Alistipes were biomarkers that showed significant differences between the groups. In addition, the microbial pathways associated with K. pneumoniae and E. coli may promote hypertension, while A. muciniphila may play a role in reversing the development of hypertension in long-lived elderly. Metabolomics revealed that HTL contained a lower concentration of fecal acetate and propionate than HTE, while it contained a higher concentration of serum acetate and urine acetate. Furthermore, their immune cells exhibited no significant changes in SCFAs receptors.

Conclusion

Although long-lived elderly have extremely high systolic blood pressure, their unique gut microbiota composition and efficient acetate absorption in the colon may offset the damages caused by hypertension and maintain healthy homeostasis.

Garcinia dulcis Flower Extract Alters Gut Microbiota and Fecal Metabolomic Profiles of 2K1C Hypertensive Rats

Garcinia dulcis (GD) extract has been found to have anti-hypertensive properties in animal studies. GD can also alter the colonic microbiota of rats. However, the effects of GD on changes in the gut microbiota and metabolomic profiles of normotensive and hypertensive rats are currently unknown. The purpose of this study was to evaluate changes in the gut microbiota and metabolomic profiles of 2-kidneys-1 clip (2K1C) hypertensive rats after feeding with GD flower extract. Rats were randomly divided into the following 4 groups: sham operation (SO) receiving corn oil (CO) (SO + CO), SO receiving GD (SO + GD), 2K1C receiving corn oil (2K1C + CO) and 2K1C receiving GD (2K1C + GD). Body weight (BW) and systolic blood pressure (SBP) were measured weekly throughout the study. Gut microbiota and fecal metabolites were measured from fresh fecal contents. Alpha diversity results demonstrated a similar microbial richness and diversity between groups. Linear discriminant analysis (LDA) effect size (LEfSe) suggested that GD treatment affected gut microbial community structure in both hypertensive and normotensive rats. Feeding rats with GD caused metabolic alterations that rendered 2K1C + GD rats similar to SO + CO and SO + GD rats. Findings suggest that the impact of GD on gut microbiota and metabolite profiles may be related to its anti-hypertensive properties.

Metabolic Dysfunction-Associated Fatty Liver Disease in Newly Diagnosed, Treatment-Naive Hypertensive Patients and Its Association with Cardiorenal Risk Markers

INTRODUCTION

Patients with arterial hypertension frequently present with comorbidities that are associated with increased cardiorenal risk, such as metabolic dysfunction-associated fatty liver disease (MAFLD).

AIMS

Our study aimed to assess the prevalence and the association of MAFLD with cardiorenal risk markers in newly diagnosed, treatment-naïve hypertensive patients.

METHODS

We recruited 281 individuals with new-onset hypertension who were not prescribed any medication. Medical history, clinical examination findings, and laboratory test results were recorded. Liver steatosis was assessed through fatty liver index (FLI) calculation. Patients with FLI ≥ 60 together with one main metabolic abnormality (type 2 diabetes mellitus or overweight/obesity) or at least two metabolic risk abnormalities (increased waist circumference, blood pressure, plasma triglycerides, presence of prediabetes or insulin resistance, decreased plasma high-density lipoprotein) fulfilled the diagnostic criteria for MAFLD.

RESULTS

The prevalence of MAFLD in our study population was 28.7%. Individuals with MAFLD were more frequently male and had increased body mass index. Systolic, diastolic, and pulse pressure values were significantly higher in this group of patients. Moreover, lipid, renal, glucose, and inflammatory markers were considerably deranged in patients with MAFLD. After multivariate regression analysis, uric acid, ferritin, and apoE emerged as independent predictors of MAFLD. Area under receiver operating characteristics curve revealed that uric acid had the greatest diagnostic accuracy, with the ideal cutoff being ≥ 5.2 mg/dl (sensitivity: 77.6%, specificity: 76.3%).

CONCLUSION

MAFLD represents a common comorbidity in hypertensive patients and is associated with markers of cardiorenal risk. Uric acid may be indicative of MAFLD in particular.

Investigating the human spirit and spirituality in pediatric patients with kidney disease

Human spirit is an integral part of the medicinal art and science trifecta: body-mind-spirit, and it is contained in the World Health Organization definition of health. Human spirit is defined as our purpose in life, relationships with all living creatures or "Higher Power", and in general our place on planet Earth. Spirituality is a required part of patient care according to Joint Commission on Accreditation of Health Care Organizations. There is an abundant medical literature that documents discrepancies in the results between studies and populations, and points to the importance of cultural, ethnic, spiritual or religious differences. Validated questionnaires used in research for last several decades demonstrated an association of spirituality with clinical outcomes, coping, and quality of life in different adult chronic diseases. There are also validated scales to measure hope in children based on the premise that children are goal directed and that their goal-related thoughts can be understood, yet their purposefulness, meaning of life and spirit in pediatric nephrology remains mostly unexamined. Although pediatric nephrology has made significant advances in molecular techniques, artificial intelligence, machine learning, and started to address more broad social issues such as racism, health equity, diversity of our work force, etc, it lacks both systematic ways of studying and philosophical approach to fostering human spirit. This mini review examines the place and knowledge gaps in human spirit and spirituality in pediatric nephrology. We review the concept of the human spirit and medical literature pertaining to its role in pediatric nephrology.

Recent Developments in Drug Targets and Combination Therapy for the Clinical Management of Hypertension

Raised blood pressure is the most common complication worldwide that may lead to atherosclerosis and ischemic heart disease. Unhealthy lifestyles, smoking, alcohol consumption, junk food, and genetic disorders are some of the causes of hypertension. To treat this condition, numerous antihypertensive medications are available, either alone or in combination, that work via various mechanisms of action. Combinational therapy provides a certain advantage over monotherapy in the sense that it acts in multi mechanism mode and minimal drug amount is required to elicit the desired therapeutic effect. Such therapy is given to patients with systolic blood pressure greater than 20 mmHg and/or diastolic blood pressure exceeding 10 mmHg beyond the normal range, as well as those suffering from severe cardiovascular disease. The selection of antihypertensive medications, such as calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and low-dose diuretics, hinges on their ability to manage blood pressure effectively and reduce cardiovascular disease risks. This review provides insights into the diverse monotherapy and combination therapy approaches used for elevated blood pressure management. In addition, it offers an analysis of combination therapy versus monotherapy and discusses the current status of these therapies, from researchbased findings to clinical trials.

Untargeted metabolomics unravel serum metabolic alterations in smokers with hypertension

Background: Cigarette smoking is an important environmental risk factor for cardiovascular events of hypertension (HTN). Existing studies have provided evidence supporting altered gut microbiota by cigarette smoking, especially in hypertensive patients. Metabolic biomarkers play a central role in the functional potentials of the gut microbiome but are poorly characterized in hypertensive smokers. To explore whether serum metabolomics signatures and compositions of HTN patients were varied in smokers, and investigate their connecting relationship to gut microbiota, the serum metabolites were examined in untreated hypertensive patients using untargeted liquid chromatography-mass spectrometry (LC/MS) analysis. Results: A dramatic difference and clear separation in community features of circulating metabolomics members were seen in smoking HTN patients compared with the non-smoking controls, according to partial least squares discrimination analysis (PLS-DA) and orthogonal partial least squares discrimination analysis (OPLS-DA). Serum metabolic profiles and compositions of smoking patients with HTN were significantly distinct from the controls, and were characterized by enrichment of 12-HETE, 7-Ketodeoxycholic acid, Serotonin, N-Stearoyl tyrosine and Deoxycholic acid glycine conjugate, and the depletion of Tetradecanedioic acid, Hippuric acid, Glyceric acid, 20-Hydroxyeicosatetraenoic acid, Phenylpyruvic acid and Capric acid. Additionally, the metabolome displayed prominent functional signatures, with a majority proportion of the metabolites identified to be discriminating between groups distributed in Starch and sucrose metabolism, Caffeine metabolism, Pyruvate metabolism, Glycine, serine and threonine metabolism, and Phenylalanine metabolic pathways. Furthermore, the observation of alterations in metabolites associated with intestinal microbial taxonomy indicated that these metabolic members might mediate the effects of gut microbiome on the smoking host. Indeed, the metabolites specific to smoking HTNs were strongly organized into co-abundance networks, interacting with an array of clinical parameters, including uric acid (UA), low-denstiy lipoprotein cholesterol (LDLC) and smoking index. Conclusions: In conclusion, we demonstrated disparate circulating blood metabolome composition and functional potentials in hypertensive smokers, showing a linkage between specific metabolites in blood and the gut microbiome.

Relationship between high fructose corn syrup sweetened drinks, diet soft drinks, and serum sodium: NHANES 2003-2006

BACKGROUND

Consumption of high fructose corn syrup sweetened drinks and diet soft drinks has increased in the United States. However, the relationship between the intake of high fructose corn syrup sweetened drinks and diet soft drinks, and serum sodium has been scarcely studied. Our objective is to evaluate the relation between intake of high fructose corn syrup sweetened drinks and diet soft drinks, and serum sodium, and explore the possible effect modifiers in a nationally representative sample of adults from the United States.

METHODS

We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey 2003-2006. The study participants included 6989 adults aged ≥18 years. Using survey-weighted generalized linear regression analyses, we investigated the relationship between high fructose corn syrup sweetened drink, diet soft drink consumption, and serum sodium. Consumption of high fructose corn syrup sweetened drinks and diet soft drinks was evaluated through a food-frequency questionnaire.

RESULTS

Serum sodium levels increased as high fructose corn syrup sweetened drink intake increased. Serum sodium levels were higher in participants in the highest high fructose corn syrup sweetened drink consumption quantile, compared with those in the lowest high fructose corn syrup sweetened drink intake quantile (p = 0.020). The multivariate betas for serum sodium, according to the corresponding high fructose corn syrup sweetened drink intake quantiles, were 0.16, 0.19, and 0.21, respectively (P for trend = 0.051). We found no relationship between diet soft drink consumption and serum sodium after adjustment of confounding. (multivariate P > 0.05).

CONCLUSION

There was a a step-wise increase in serum sodium concentration with increasing consumption of HFCS sweetened beverages. Even moderate HFCS sweetened soft drink intake was associated with an elevated serum sodium level - a risk factor for hypertension.

Gut mycobiome dysbiosis contributes to the development of hypertension and its response to immunoglobulin light chains

Objectives

Human gut microbiome has gained great attention for its proposed roles in the development of hypertension. The fungal microbiome in the human gut (i.e. the mycobiome) is beginning to gain recognition as a fundamental part of our microbiome. However, the existing knowledge of human mycobiome has never revealed the association between gut mycobiome and hypertension. It is known that inflammation and immunity contribute to human hypertension. Here, we sought to investigate whether gut mycobiome could predict the development of hypertension and its association with immunoglobulin light chains.

Methods and materials

Participants were classified into three cohorts: prehypertension (pre-HTN), hypertension (HTN), and normal-tension (NT) based on their blood pressure. Fresh samples were collected, and the ITS transcribed spacer ribosomal RNA gene sequence was performed. An immunoturbidimetric test was used to examine the serum levels of immunological light chains.

Results

Subjects in both of the states of pre-HTN and HTN had different fungal microbiome community compared to the NT group (FDR<0.05). Slightly higher levels of fungal richness and diversity were observed in the groups of pre-HTN and HTN. The relative abundance of Malassezia increased in the HTN group compared to that in the NT group, and the relative abundance of Mortierella enriched in the NT group. For the pre-HTN group, the relative abundance of Malassezia was positively associated with serum the concentration of light chain (LC) κ (r=0.510, P=0.044); for the HTN group, the relative abundance of Mortierella was positively associated with the serum concentration of LC κ (P<0.05), the relative abundance of Malassezia was positively associated with both the serum concentrations of LC κ and LC λ (r>0.30, P<0.05).

Conclusions

Our present study demonstrated that gut fungal dysbiosis occurred in the state of prehypertension, and fungal dysbiosis can predict the dysregulation of serum light chains in hypertension patients. Further study on modulating gut fungal community should be focused on balancing the immunological features in hypertension.