The Microbiome and Blood Pressure: Can Microbes Regulate Our Blood Pressure?

Childhood Hypertension and Effects on Cognitive Functions: Mechanisms and Future Perspectives

Pediatric hypertension is currently one of the most common health concerns in children, given its effects not only on cardiovascular but also cognitive functions. There is accumulating evidence suggesting neurocognitive dysfunction in hypertensive children that could persist even into adulthood. Identifying the precise mechanism(s) underlying the association between childhood hypertension and cognitive dysfunction is crucial as it could potentially lead to the discovery of "druggable" biological targets facilitating the development of treatments. Here, we discuss some of the proposed pathophysiological mechanisms underlying childhood hypertension and cognitive deficits and suggest strategies to address some of the current challenges in the field. The various research studies involving hypertensive adults indicate that long-term hypertension may produce abnormal cerebrovascular reactivity, chronic inflammation, autonomic dysfunction, or hyperinsulinemia and hypercholesterolemia, which could lead to alterations in the brain's structure and functions, resulting in cognitive dysfunction. In light of the current literature, we propose that dysregulation of the hypothalamus-pituitaryadrenal axis, modifications in endothelial brain-derived neurotrophic factor and the gut microbiome may also modulate cognitive functions in hypertensive individuals. Moreover, the above-mentioned pathological states may further intensify the detrimental effects of hypertension on cognitive functions. Thus, treatments that target not only hypertension but also its downstream effects may prove useful in ameliorating hypertension-induced cognitive deficits. Much remains to be clarified about the mechanisms and treatments of hypertension-induced cognitive outcomes in pediatric populations. Addressing the knowledge gaps in this field entails conducting not only clinical research but also rigorous basic and translational studies.

Maternal N-Acetylcysteine Therapy Prevents Hypertension in Spontaneously Hypertensive Rat Offspring: Implications of Hydrogen Sulfide-Generating Pathway and Gut Microbiota

Hypertension can come from early life. N-acetylcysteine (NAC), a hydrogen sulfide (H₂S) precursor as well as an antioxidant, has antihypertensive effect. We investigated whether maternal NAC therapy can protect spontaneously hypertensive rats (SHR) male offspring against hypertension. The pregnant rats were assigned to four groups: SHRs without treatment; Wistar Kyoto (WKY) without treatment; SHR+NAC, SHRs received 1% NAC in drinking water throughout pregnancy and lactation; and, WKY+NAC, WKY rats received 1% NAC in drinking water during pregnancy and lactation. Male offspring (n = 8/group) were killed at 12 weeks of age. Maternal NAC therapy prevented the rise in systolic blood pressure (BP) in male SHR offspring at 12 weeks of age. Renal cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulphurtransferase (3MST) protein levels and H₂S-releasing activity were increased in the SHR+NAC offspring. Maternal NAC therapy increased fecal H₂S and thiosulfate levels in the SHR+NAC group. Additionally, maternal NAC therapy differentially shaped gut microbiota and caused a distinct enterotype in each group. The protective effect of maternal NAC therapy against hypertension in SHR offspring is related to increased phylum Actinobacteria and genera Bifidobacterium and Allobaculum, but decreased phylum Verrucomicrobia, genera Turicibacter, and Akkermansia. Several microbes were identified as microbial markers, including genera Bifidobacterium, Allobaculum, Holdemania, and Turicibacter. Our results indicated that antioxidant therapy by NAC in pregnant SHRs can prevent the developmental programming of hypertension in male adult offspring. Our findings highlight the interrelationships among H₂S-generating pathway in the kidneys and gut, gut microbiota, and hypertension. The implications of maternal NAC therapy elicited long-term protective effects on hypertension in later life that still await further clinical translation.

Longitudinal Analysis of Serum Cytokine Levels and Gut Microbial Abundance Links IL-17/IL-22 With Clostridia and Insulin Sensitivity in Humans

Recent studies using mouse models suggest that interaction between the gut microbiome and IL-17/IL-22-producing cells plays a role in the development of metabolic diseases. We investigated this relationship in humans using data from the prediabetes study of the Integrated Human Microbiome Project (iHMP). Specifically, we addressed the hypothesis that early in the onset of metabolic diseases there is a decline in serum levels of IL-17/IL-22, with concomitant changes in the gut microbiome. Clustering iHMP study participants on the basis of longitudinal IL-17/IL-22 profiles identified discrete groups. Individuals distinguished by low levels of IL-17/IL-22 were linked to established markers of metabolic disease, including insulin sensitivity. These individuals also displayed gut microbiome dysbiosis, characterized by decreased diversity, and IL-17/IL-22-related declines in the phylum Firmicutes, class Clostridia, and order Clostridiales This ancillary analysis of the iHMP data therefore supports a link between the gut microbiome, IL-17/IL-22, and the onset of metabolic diseases. This raises the possibility for novel, microbiome-related therapeutic targets that may effectively alleviate metabolic diseases in humans as they do in animal models.

Targeting on Gut Microbiota-Derived Metabolite Trimethylamine to Protect Adult Male Rat Offspring against Hypertension Programmed by Combined Maternal High-Fructose Intake and Dioxin Exposure

Gut microbiota-dependent metabolites, in particular trimethylamine (TMA), are linked to hypertension. Maternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure or consumption of food high in fructose (HFR) can induce hypertension in adult offspring. We examined whether 3,3-maternal dimethyl-1-butanol (DMB, an inhibitor of TMA formation) therapy can protect adult offspring against hypertension arising from combined HFR and TCDD exposure. Pregnant Sprague-Dawley rats received regular chow or chow supplemented with fructose (60% diet by weight) throughout pregnancy and lactation. Additionally, the pregnant dams received TCDD (200 ng/kg BW orally) or a corn oil vehicle on days 14 and 21 of gestation, and days 7 and 14 after birth. Some mother rats received 1% DMB in their drinking water throughout pregnancy and lactation. Six groups of male offspring were studied (n = 8 for each group): regular chow (CV), high-fructose diet (HFR), regular diet+TCDD exposure (CT), HFR+TCDD exposure (HRT), high-fructose diet+DMB treatment (HRD), and HFR+TCDD+DMB treatment (HRTD). Our data showed that TCDD exacerbates HFR-induced elevation of blood pressure in male adult offspring, which was prevented by maternal DMB administration. We observed that different maternal insults induced distinct enterotypes in adult offspring. The beneficial effects of DMB are related to alterations of gut microbiota, the increase in nitric oxide (NO) bioavailability, the balance of the renin-angiotensin system, and antagonization of aryl hydrocarbon receptor (AHR) signaling. Our findings cast new light on the role of early intervention targeting of the gut microbiota-dependent metabolite TMA, which may allow us to prevent the development of hypertension programmed by maternal excessive fructose intake and environmental dioxin exposure.

Plant-Based Diets and Hypertension

Hypertension is a global epidemic and a risk factor for many adverse outcomes, including cardiovascular disease, kidney disease, and death. Lifestyle plays a significant role in the development and maintenance of hypertension, and guidelines from several organizations recommend lifestyle modifications as first-line intervention for hypertensive patients. Data supporting the use of plant-based diets in the treatment of hypertension goes back almost a century. More recently, clinical trial data, including randomized controlled trials, have established plant-based diets as an effective lifestyle intervention for high blood pressure (BP). Plant-based diets differ from the standard American diet in a myriad of ways, with some substances being present in either substantially higher or lower amounts. Although the precise mechanism of a plant-based diet's beneficial effects on BP is unknown, many of these differences may be responsible. Attributes of a plant-based diet that may lower BP include a lower energy content leading to weight loss, a lower sodium content, an increased potassium content, reduced oxidative stress, higher bioavailability of the vasodilator nitric oxide, and beneficial effects on the microbiome. The evidenced-based benefits of plant-based diets in treating hypertension should lead providers to advocate for this dietary pattern for their patients.

Amino Acids and Developmental Origins of Hypertension

During pregnancy, amino acids are important biomolecules that play essential roles in fetal growth and development. Imbalanced amino acid intake during gestation may produce long-term morphological or functional changes in offspring, for example, developmental programming that increases the risk of developing hypertension in later life. Conversely, supplementation with specific amino acids could reverse the programming processes in early life, which may counteract the rising epidemic of hypertension. This review provides an overview of the evidence supporting the importance of amino acids during pregnancy and fetal development, the impact of amino acids on blood pressure regulation, insight from animal models in which amino acids were used to prevent hypertension of developmental origin, and interactions between amino acids and the common mechanisms underlying development programming of hypertension. A better understanding of the pathophysiological roles of specific amino acids and their interactions in developmental programming of hypertension is essential so that pregnant mothers are able to benefit from accurate amino acid supplementation during pregnancy in order to prevent hypertension development in their children.

Metabolites and Hypertension: Insights into Hypertension as a Metabolic Disorder: 2019 Harriet Dustan Award

For over 100 years, essential hypertension has been researched from different perspectives ranging from genetics, physiology, and immunology to more recent ones encompassing microbiology (microbiota) as a previously underappreciated field of study contributing to the cause of hypertension. Each field of study in isolation has uniquely contributed to a variety of underlying mechanisms of blood pressure regulation. Even so, clinical management of essential hypertension has remained somewhat static. We, therefore, asked if there are any converging lines of evidence from these individual fields that could be amenable for a better clinical prognosis. Accordingly, here we present converging evidence which support the view that metabolic dysfunction underlies essential hypertension.

The influence of wasabi on the gut microbiota of high-carbohydrate, high-fat diet-induced hypertensive Wistar rats

The human gut microbiota plays a critical role in the regulation of adiposity, obesity and metabolic and cardiovascular disease. Wasabi is a pungent spice and its active component, allyl isothiocyanate, improves plasma triacylglycerol, cholesterol and high blood pressure in rodents, but it is unclear if this occurs through alterations to the composition of the microbiota. The aim of this study was to determine the effectiveness of Wasabi japonica stem and rhizome blend on ameliorating cardiovascular disease parameters including plasma sodium concentration, systolic blood pressure (SBP), plasma endothelin-1 and angiotensin II concentrations by altering the gut microbiota in a Wistar rat model of obesity and metabolic syndrome. Rats were randomized to receive a corn starch or high-carbohydrate/high-fat diet for 8 weeks before being allocated to supplementation with wasabi powder (5% (w/w) in food) or not for an additional 8 weeks. At the end of the trial, rats were grouped according to blood pressure status. Wasabi supplementation prevented the development of hypertension and was also associated with significantly increased abundance of Allobaculum, Sutterella, Uncl. S247, Uncl. Coriobacteriaceae and Bifidobacterium. Hypertension was positively correlated with higher abundance of Oscillospira, Uncl. Lachnospiraceae and Uncl. Clostridiales, Uncl. Bacteroidales and Butyricimonas. Oscillospira and Butyricimonas abundances were specifically positively correlated with systolic blood pressure. Overall, the improved host cardiovascular health in diet-induced obese rats supplemented with wasabi powder may involve changes to the gut microbiota composition.

Early-Life Programming and Reprogramming of Adult Kidney Disease and Hypertension: The Interplay between Maternal Nutrition and Oxidative Stress

Kidney disease and hypertension both have attained the status of a global pandemic. Altered renal programming resulting in kidney disease and hypertension can begin in utero. Maternal suboptimal nutrition and oxidative stress have important implications in renal programming, while specific antioxidant nutrient supplementations may serve as reprogramming strategies to prevent kidney disease and hypertension of developmental origins. This review aims to summarize current knowledge on the interplay of maternal nutrition and oxidative stress in response to early-life insults and its impact on developmental programming of kidney disease and hypertension, covering two aspects. Firstly, we present the evidence from animal models supporting the implication of oxidative stress on adult kidney disease and hypertension programmed by suboptimal maternal nutrition. In the second part, we document data on specific antioxidant nutrients as reprogramming strategies to protect adult offspring against kidney disease and hypertension from developmental origins. Research into the prevention of kidney disease and hypertension that begin early in life will have profound implications for future health.

Prior Toxoplasma Gondii Infection Ameliorates Liver Fibrosis Induced by Schistosoma Japonicum through Inhibiting Th2 Response and Improving Balance of Intestinal Flora in Mice

Schistosomiasis is an immunopathogenic disease in which a T helper (Th) cell type 2-like response plays vital roles. Hepatic fibrosis is its main pathologic manifestations, which is the leading cause of hepatic cirrhosis. Co-infections of Schistosoma japonicum (Sj) with other pathogens are frequently encountered but are easily ignored in clinical studies, and effective therapeutic interventions are lacking. In this study, we explored the effect of Toxoplasma gondii (Tg) prior infection on Th1/Th2 response, community shifts in gut microbiome (GM), and the pathogenesis of schistosomiasis in murine hosts. Mice were prior infected with Tg before Sj infection. The effects of co-infection on Th1/Th2 response and hepatic fibrosis were analyzed. Furthermore, we investigated this issue by sequencing 16S rRNA from fecal specimens to define the GM profiles during co-infection. Tg prior infection markedly reduced the granuloma size and collagen deposit in livers against Sj infection. Prior infection promoted a shift toward Th1 immune response instead of Th2. Furthermore, Tg infection promoted the expansion of preponderant flora and Clostridiaceae was identified as a feature marker in the GM of the co-infection group. Redundancy analysis (RDA)/canonical correspondence analysis (CCA) results showed that liver fibrosis, Th1/Th2 cytokines were significantly correlated (P < 0.05) with the GM compositions. Tg infection inhibits hepatic fibrosis by downregulating Th2 immune response against Sj infection, and further promotes the GM shifts through "gut-liver axis" in the murine hosts. Our study may provide insights into potential anti-fibrosis strategies in co-infection individuals.

Taxonomic classification and abundance estimation using 16S and WGS-A comparison using controlled reference samples

The assessment of microbiome biodiversity is the most common application of metagenomics. While 16S sequencing remains standard procedure for taxonomic profiling of metagenomic data, a growing number of studies have clearly demonstrated biases associated with this method. By using Whole Genome Shotgun sequencing (WGS) metagenomics, most of the known restrictions associated with 16S data are alleviated. However, due to the computationally intensive data analyses and higher sequencing costs, WGS based metagenomics remains a less popular option. Selecting the experiment type that provides a comprehensive, yet manageable amount of information is a challenge encountered in many metagenomics studies. In this work, we created a series of artificial bacterial mixes, each with a different distribution of skin-associated microbial species. These mixes were used to estimate the resolution of two different metagenomic experiments - 16S and WGS - and to evaluate several different bioinformatics approaches for taxonomic read classification. In all test cases, WGS approaches provide much more accurate results, in terms of taxa prediction and abundance estimation, in comparison to those of 16S. Furthermore, we demonstrate that a 16S dataset, analysed using different state of the art techniques and reference databases, can produce widely different results. In light of the fact that most forensic metagenomic analysis are still performed using 16S data, our results are especially important.

Mechanisms of the protective effects of nitrate and nitrite in cardiovascular and metabolic diseases

Within the body, NO is produced by nitric oxide synthases via converting _l-arginine to citrulline. Additionally, NO is also produced via the NOS-independent nitrate-nitrite-NO pathway. Unlike the classical pathway, the nitrate-nitrite-NO pathway is oxygen independent and viewed as a back-up function to ensure NO generation during ischaemia/hypoxia. Dietary nitrate and nitrite have emerged as substrates for endogenous NO generation and other bioactive nitrogen oxides with promising protective effects on cardiovascular and metabolic function. In brief, inorganic nitrate and nitrite can decrease blood pressure, protect against ischaemia-reperfusion injury, enhance endothelial function, inhibit platelet aggregation, modulate mitochondrial function and improve features of the metabolic syndrome. However, many questions regarding the specific mechanisms of these protective effects on cardiovascular and metabolic diseases remain unclear. In this review, we focus on nitrate/nitrite bioactivation, as well as the potential mechanisms for nitrate/nitrite-mediated effects on cardiovascular and metabolic diseases. Understanding how dietary nitrate and nitrite induce beneficial effect on cardiovascular and metabolic diseases could open up novel therapeutic opportunities in clinical practice.

Microbiome as an Immunological Modifier

Humans are living ecosystems composed of human cells and microbes. The microbiome is the collection of microbes (microbiota) and their genes. Recent breakthroughs in the high-throughput sequencing technologies have made it possible for us to understand the composition of the human microbiome. Launched by the National Institutes of Health in USA, the human microbiome project indicated that our bodies harbor a wide array of microbes, specific to each body site with interpersonal and intrapersonal variabilities. Numerous studies have indicated that several factors influence the development of the microbiome including genetics, diet, use of antibiotics, and lifestyle, among others. The microbiome and its mediators are in a continuous cross talk with the host immune system; hence, any imbalance on one side is reflected on the other. Dysbiosis (microbiota imbalance) was shown in many diseases and pathological conditions such as inflammatory bowel disease, celiac disease, multiple sclerosis, rheumatoid arthritis, asthma, diabetes, and cancer. The microbial composition mirrors inflammation variations in certain disease conditions, within various stages of the same disease; hence, it has the potential to be used as a biomarker.

Integrating omics for a better understanding of Inflammatory Bowel Disease: a step towards personalized medicine

Background

Inflammatory Bowel Disease (IBD) is a multifactorial chronic disease. Understanding only one aspect of IBD pathogenesis does not reflect the complex nature of IBD nor will it improve its clinical management. Therefore, it is vital to dissect the interactions between the different players in IBD pathogenesis in order to understand the biology of the disease and enhance its clinical outcomes.

Aims

To provide an overview of the available omics data used to assess the potential mechanisms through which various players are contributing to IBD pathogenesis and propose a precision medicine model to fill the current knowledge gap in IBD.

Results

Several studies have reported microbial dysbiosis, immune and metabolic dysregulation in IBD patients, however, this data is not sufficient to create signatures that can differentiate between the disease subtypes or between disease relapse and remission.

Conclusions

We summarized the current knowledge in the application of omics in IBD patients, and we showed that the current knowledge gap in IBD hinders the improvements of clinical decision for treatment as well as the prediction of disease relapse. We propose one way to fill this gap by implementing integrative analysis of various omics datasets generated from one patient at a single time point.

Hypertension Programmed by Perinatal High-Fat Diet: Effect of Maternal Gut Microbiota-Targeted Therapy

Hypertension can originate in early life caused by perinatal high-fat (HF) consumption. Gut microbiota and their metabolites short chain fatty acids (SCFAs), trimethylamine (TMA), and trimethylamine N-oxide (TMAO) are involved in the development of hypertension. Despite the beneficial effects of prebiotic/probiotic on human health, little is known whether maternal use of prebiotics/probiotics could protect offspring against the development of hypertension in adulthood. We investigated whether perinatal HF diet-induced programmed hypertension in adult offspring can be prevented by therapeutic uses of prebiotic inulin or probiotic Lactobacillus casei during gestation and lactation. Pregnant Sprague–Dawley rats received regular chow or HF diet (D12331, Research Diets), with 5% w/w long chain inulin (PRE), or 2 × 10⁸ CFU/day Lactobacillus casei via oral gavage (PRO) during pregnancy and lactation. Male offspring (n = 8/group) were assigned to four groups: control, HF, PRE, and PRO. Rats were sacrificed at 16 weeks of age. Maternal prebiotic or probiotic therapy prevents elevated blood pressure (BP) programmed by perinatal HF consumption. Both prebiotic and probiotic therapies decreased the Firmicutes to Bacteroidetes ratio and renal mRNA expression of Ace, but increased abundance of genus Lactobacillus and Akkermansia. Additionally, prebiotic treatment prevents HF-induced elevation of BP is associated with reduced fecal propionate and acetate levels, while probiotic therapy restored several Lactobacillus species. Maternal probiotic or prebiotic therapy caused a reduction in plasma TMAO level and TMAO-to-TMA ratio. The beneficial effects of prebiotic or probiotic therapy on elevated BP programmed by perinatal HF diet are relevant to alterations of microbial populations, modulation of microbial-derived metabolites, and mediation of the renin-angiotensin system. Our results cast a new light on the use of maternal prebiotic/probiotic therapy to prevent hypertension programmed by perinatal HF consumption. The possibility of applying gut microbiota-targeted therapies as a reprogramming strategy for hypertension warrants further clinical translation.

Prebiotic supplementation modulates advanced glycation end-products (AGEs), soluble receptor for AGEs (sRAGE), and cardiometabolic risk factors through improving metabolic endotoxemia: a randomized-controlled clinical trial

PURPOSE

The oxidative stress plays a key role in the initiation, propagation, and development of the complications of type 2 diabetes mellitus (T2DM). This trial aimed to evaluate the effects of resistant dextrin as a prebiotic on the cardiometabolic risk factors and the status of oxidative stress in patients with T2DM.

METHODS

Sixty-five female subjects with T2DM were assigned to either the intervention (n = 33) or control (n = 32) groups receiving 10 g/day of resistant dextrin or placebo, respectively, for 8 weeks. Fasting blood samples were collected at baseline and post-intervention to determine the serum levels of glycemic indices, lipid profile, atherogenic indices, and soluble receptor for AGEs (sRAGE), carboxymethyl lysine (CML), pentosidine, malondialdehyde (MDA), 8-iso-prostaglandin F2α (8-iso-PGF2α), total antioxidant capacity (TAC), antioxidant enzymes activity, and uric acid. Data were analyzed using SPSS software 17. Paired, unpaired Student's t tests, and analysis of covariance were used to compare the quantitative variables.

RESULTS

Resistant dextrin caused a significant decrease in FPG (- 17.43 mg/dl, 9.80%), TG (- 40.25 mg/dl, 23.01%), TC/HDL (- 0.80, 21.87%), LDL-c/HDL-c (- 0.80, 17.85%), Atherogenic index (- 0.40, 15.80%), LPS (- 6.5 EU/ml, 23.40%) and hs-CRP (- 8.02 ng/ml, 54.00%), MDA (- 1.21 nmol/mL, 25.58%), CML (- 93.40 ng/ml, 26.30%), 8-iso-PGF2α (- 4.65 pg/ml, 15.00%), and a significant increase in TAC (0.33 mmol/L, 36.25%) and s-RAGE (2.10 ng/ml, 28.90%) in the intervention group compared with the control group. No significant changes were observed in glycosylated hemoglobin, total cholesterol, LDL-c, HDL-c, superoxide dismutase, glutathione peroxidase and catalase, pentosidine, and uric acid in the intervention group compared with the control group.

CONCLUSIONS

Supplementation with resistant dextrin may improve the advanced glycation end-products, sRAGE, and cardiometabolic risk factors in women with type 2 diabetes mellitus.

The gut microbiota and its relationship with chronic kidney disease

Chronic kidney disease (CKD) is a worldwide health problem, because it is one of the most common complications of metabolic diseases including obesity and type 2 diabetes. Patients with CKD also develop other comorbidities, such as hypertension, hyperlipidemias, liver and cardiovascular diseases, gastrointestinal problems, and cognitive deterioration, which worsens their health. Therapy includes reducing comorbidities or using replacement therapy, such as peritoneal dialysis, hemodialysis, and organ transplant. Health care systems are searching for alternative treatments for CKD patients to mitigate or retard their progression. One new topic is the study of uremic toxins (UT), which are excessively produced during CKD as products of food metabolism or as a result of the loss of renal function that have a negative impact on the kidneys and other organs. High urea concentrations significantly modify the microbiota in the gut also, cause a decrease in bacterial strains that produce anti-inflammatory and fuel molecules and an increase in bacterial strains that can metabolize urea, but also produce UT, including indoxyl sulfate and p-cresol sulfate. UT activates several cellular processes that induce oxidative environments, inflammation, proliferation, fibrosis development, and apoptosis; these processes mainly occur in the gut, heart, and kidney. The study of the microbiota during CKD allowed for the implementation of therapy schemes to try to reduce the circulating concentrations of UT and reduce the damage. The objective of this review is to show an overview to know the main UT produced in end-stage renal disease patients, and how prebiotics and probiotics intervention acts as a helpful tool in CKD treatment.

New Insights on the Role of Sodium in the Physiological Regulation of Blood Pressure and Development of Hypertension

A precise maintenance of sodium and fluid balance is an essential step in the regulation of blood pressure and alterations of this balance may lead to the development of hypertension. In recent years, several new advances were made in our understanding of the interaction between sodium and blood pressure regulation. The first is the discovery made possible with by new technology, such as ²³Na-MRI, that sodium can be stored non-osmotically in tissues including the skin and muscles particularly when subjects are on a high sodium diet or have a reduced renal capacity to excrete sodium. These observations prompted the refinement of the original model of regulation of sodium balance from a two-compartment model comprising the extracellular fluid within the intravascular and interstitial spaces to a three-compartment model that includes the intracellular space of some tissues, most prominently the skin. In this new model, the immune system plays a role, thereby supporting many previous studies indicating that the immune system is a crucial co-contributor to the maintenance of hypertension through pro-hypertensive effects in the kidney, vasculature, and brain. Lastly, there is now evidence that sodium can affect the gut microbiome, and induce pro-inflammatory and immune responses, which might contribute to the development of salt-sensitive hypertension.

Taking Systems Medicine to Heart

Systems medicine is a holistic approach to deciphering the complexity of human physiology in health and disease. In essence, a living body is constituted of networks of dynamically interacting units (molecules, cells, organs, etc) that underlie its collective functions. Declining resilience because of aging and other chronic environmental exposures drives the system to transition from a health state to a disease state; these transitions, triggered by acute perturbations or chronic disturbance, manifest as qualitative shifts in the interactions and dynamics of the disease-perturbed networks. Understanding health-to-disease transitions poses a high-dimensional nonlinear reconstruction problem that requires deep understanding of biology and innovation in study design, technology, and data analysis. With a focus on the principles of systems medicine, this Review discusses approaches for deciphering this biological complexity from a novel perspective, namely, understanding how disease-perturbed networks function; their study provides insights into fundamental disease mechanisms. The immediate goals for systems medicine are to identify early transitions to cardiovascular (and other chronic) diseases and to accelerate the translation of new preventive, diagnostic, or therapeutic targets into clinical practice, a critical step in the development of personalized, predictive, preventive, and participatory (P4) medicine.

The Interplay between Maternal and Post-Weaning High-Fat Diet and Gut Microbiota in the Developmental Programming of Hypertension

Excessive intake of saturated fat has been linked to hypertension. Gut microbiota and their metabolites, short-chain fatty acids (SCFAs), are known to be involved in the development of hypertension. We examined whether maternal and post-weaning high-fat (HF) diet-induced hypertension in adult male offspring is related to alterations of gut microbiota, mediation of SCFAs and their receptors, and downregulation of nutrient-sensing signals. Female Sprague–Dawley rats received either a normal diet (ND) or HF diet (D12331, Research Diets) during pregnancy and lactation. Male offspring were put on either the ND or HF diet from weaning to 16 weeks of age, and designated to four groups (maternal diet/post-weaning diet; n = 8/group): ND/ND, HF/ND, ND/HF, and HF/HF. Rats were sacrificed at 16 weeks of age. Combined HF/HF diets induced elevated blood pressure (BP) and increased body weight and kidney damage in male adult offspring. The rise in BP is related to a downregulated AMP-activated protein kinase (AMPK)–peroxisome proliferator-activated receptor co-activator 1α (PGC-1α) pathway. Additionally, HF/HF diets decreased fecal concentrations of propionate and butyrate and decreased G protein-coupled receptor 41 (GPR41), but increased olfactory receptor 78 (Oflr78) expression. Maternal HF diet has differential programming effects on the offspring’s microbiota at 3 and 16 weeks of age. Combined HF/HF diet induced BP elevation was associated with an increased Firmicutes to Bacteroidetes ratio, increased abundance of genus Akkermansia and phylum Verrucomicrobia, and reduced abundance in genus Lactobacillus. Maternal gut microbiota-targeted dietary interventions might be reprogramming strategies to protect against programmed hypertension in children and their mothers on consumption of a fat-rich diet.

Blood Pressure Abnormalities Associated with Gut Microbiota-Derived Short Chain Fatty Acids in Children with Congenital Anomalies of the Kidney and Urinary Tract

Both kidney disease and hypertension can originate from early life. Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of chronic kidney disease (CKD) in children. Since gut microbiota and their metabolite short chain fatty acids (SCFAs) have been linked to CKD and hypertension, we examined whether gut microbial composition and SCFAs are correlated with blood pressure (BP) load and renal outcome in CKD children with CAKUT. We enrolled 78 children with CKD stage G1-G4. Up to 65% of children with CAKUT had BP abnormalities on 24 h ambulatory blood pressure monitoring (ABPM). CKD children with CAKUT had lower risk of developing BP abnormalities and CKD progression than those with non-CAKUT. Reduced plasma level of propionate was found in children with CAKUT, which was related to increased abundance of phylum Verrucomicrobia, genus Akkermansia, and species Bifidobacterium bifidum. CKD children with abnormal ABPM profile had higher plasma levels of propionate and butyrate. Our findings highlight that gut microbiota-derived SCFAs like propionate and butyrate are related to BP abnormalities in children with an early stage of CKD. Early assessments of these microbial markers may aid in developing potential targets for early life intervention for lifelong hypertension prevention in childhood CKD.

Targeting on Gut Microbial Metabolite Trimethylamine-N-Oxide and Short-Chain Fatty Acid to Prevent Maternal High-Fructose-Diet-Induced Developmental Programming of Hypertension in Adult Male Offspring

SCOPE

Alterations of gut metabolites, such as SCFAs and trimethylamine (TMA), and microbial composition are associated with the development of hypertension. Whether maternal 3,3-dimethyl-1-butanol (DMB, an inhibitor for TMA formation) treatment or the predominant SCFA acetate supplementation can prevent programed hypertension induced by a high-fructose diet (HFD) exposure during pregnancy and lactation in adult male offspring is examined.

METHODS AND RESULTS

Male offspring are divided into four groups: ND, normal diet; HFD, 60% HFD; ACE, HFD plus 200 mmol L^-1 magnesium acetate in drinking water; and DMB: HFD plus 1% DMB in drinking water. Maternal HFD induces programed hypertension in adult male offspring, which is prevented by maternal acetate supplementation or DMB treatment. HFD-induced hypertension is relevant to increased plasma levels of TMA and acetate, and alterations of gut microbial composition. The protective effects of acetate supplementation are associated with decreased plasma TMA level and TMA-to-trimethylamine-N-oxide (TMAO) ratio, and increased renal expression of SCFA receptors. Maternal DMB treatment reduces plasma TMA, TMAO, acetate, and propionate levels.

CONCLUSION

Early intervention targeting on gut-microbiota-derived metabolites TMAO and SCFAs to reprogram hypertension may have significant impact to reduce the burden of hypertension.

Resveratrol prevents combined prenatal NG-nitro-L-arginine-methyl ester (L-NAME) treatment plus postnatal high-fat diet induced programmed hypertension in adult rat offspring: interplay between nutrient-sensing signals, oxidative stress and gut microbiota

Oxidative stress, nutrient-sensing signals, high-fat (HF) intake and dysbiosis of gut microbiota are involved in the development of hypertension, a disorder that can originate in early life. We examined whether postnatal HF diet can aggravate maternal N^G-nitro-L-arginine-methyl ester (L-NAME) treatment-induced programmed hypertension and whether resveratrol therapy can prevent it. Pregnant Sprague-Dawley rats received L-NAME administration at 60 mg/kg/day subcutaneously during pregnancy alone, or with additional resveratrol (R) 50 mg/L in drinking water during the pregnancy and lactation. The offspring were onto either regular chow or HF diet (D12331) from weaning to 16 weeks of age. Male offspring rats were assigned to five groups (N=8/group): control, L-NAME, HF, L-NAME+HF and L-NAME+HF + R at weaning at 3 weeks of age. Rats were sacrificed at 16 weeks of age. We observed that postnatal HF diet exacerbates maternal L-NAME treatment-induced programmed hypertension in male adult offspring, which resveratrol attenuated. Combined L-LAME and HF diet-induced hypertension is related to increased oxidative stress, inhibiting AMP-activated protein kinase (AMPK)/ peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) pathway and altered gut microbiota compositions. L-NAME+HF caused an increase of the Firmicutes to Bacteroidetes ratio, which resveratrol therapy prevented. Additionally, the abundances of phylum Verrucomicrobia and genus Akkermansia were amplified by resveratrol therapy. Conclusively, our data highlighted the interactions between maternal NO deficiency, HF diet, AMPK/PGC-1α pathway and gut microbiota in which the blood pressure of adult offspring can be modified by resveratrol. Resveratrol might be a useful reprogramming strategy to prevent L-NAME and HF diet-induced hypertension of developmental origin.

The Good, the Bad, and the Ugly of Pregnancy Nutrients and Developmental Programming of Adult Disease

Maternal nutrition plays a decisive role in developmental programming of many non-communicable diseases (NCDs). A variety of nutritional insults during gestation can cause programming and contribute to the development of adult-onset diseases. Nutritional interventions during pregnancy may serve as reprogramming strategies to reverse programming processes and prevent NCDs. In this review, firstly we summarize epidemiological evidence for nutritional programming of human disease. It will also discuss evidence from animal models, for the common mechanisms underlying nutritional programming, and potential nutritional interventions used as reprogramming strategies.

Green Coffee Extract Improves Cardiometabolic Parameters and Modulates Gut Microbiota in High-Fat-Diet-Fed ApoE-/- Mice

Chlorogenic acids (CGA) are the most abundant phenolic compounds in green coffee beans and in the human diet and have been suggested to mitigate several cardiometabolic risk factors. Here, we aimed to evaluate the effect of a water-based standardized green coffee extract (GCE) on cardiometabolic parameters in ApoE-/- mice and to explore the potential underlying mechanisms. Mice were fed an atherogenic diet without (vehicle) or with GCE by gavage (equivalent to 220 mg/kg of CGA) for 14 weeks. We assessed several metabolic, pathological, and inflammatory parameters and inferred gut microbiota composition, diversity, and functional potential. Although GCE did not reduce atherosclerotic lesion progression or plasma lipid levels, it induced important favorable changes. Specifically, improved metabolic parameters, including fasting glucose, insulin resistance, serum leptin, urinary catecholamines, and liver triglycerides, were observed. These changes were accompanied by reduced weight gain, decreased adiposity, lower inflammatory infiltrate in adipose tissue, and protection against liver damage. Interestingly, GCE also modulated hepatic IL-6 and total serum IgM and induced shifts in gut microbiota. Altogether, our results reveal the cooccurrence of these beneficial cardiometabolic effects in response to GCE in the same experimental model and suggest potential mediators and pathways involved.

Regulation of Nitric Oxide Production in the Developmental Programming of Hypertension and Kidney Disease

Development of the kidney can be altered in response to adverse environments leading to renal programming and increased vulnerability to the development of hypertension and kidney disease in adulthood. By contrast, reprogramming is a strategy shifting therapeutic intervention from adulthood to early life to reverse the programming processes. Nitric oxide (NO) is a key mediator of renal physiology and blood pressure regulation. NO deficiency is a common mechanism underlying renal programming, while early-life NO-targeting interventions may serve as reprogramming strategies to prevent the development of hypertension and kidney disease. This review will first summarize the regulation of NO in the kidney. We also address human and animal data supporting the link between NO system and developmental programming of hypertension and kidney disease. This will be followed by the links between NO deficiency and the common mechanisms of renal programming, including the oxidative stress, renin–angiotensin system, nutrient-sensing signals, and sex differences. Recent data from animal studies have suggested that interventions targeting the NO pathway could be reprogramming strategies to prevent the development of hypertension and kidney disease. Further clinical studies are required to bridge the gap between animal models and clinical trials in order to develop ideal NO-targeting reprogramming strategies and to be able to have a lifelong impact, with profound savings in the global burden of hypertension and kidney disease.

Exposure to Titanium Dioxide Nanoparticles During Pregnancy Changed Maternal Gut Microbiota and Increased Blood Glucose of Rat

Titanium dioxide nanoparticles (TiO2 NPs) were used worldwide for decades, and pregnant women are unable to avoid exposing to them. Studies revealed that TiO2 NPs could kill many kinds of bacteria, but whether they would affect the composition of gut microbiota, especially during pregnancy, was seldom reported. And, what adverse effects may be brought to pregnant females was also unknown. In this study, we established the prenatal exposure model of rats to explore the effects of TiO2 NPs on gut microbiota. We observed an increasing trend, but not a significant change of alpha-diversity among control and exposure groups at gestation day (GD) 10 and GD 17 during normal pregnancy process. Each different time point had unique gut microbiota operational taxonomic units (OTUs) characteristics. The abundance of Ellin6075 decreased at GD 10 and GD 17, Clostridiales increased at GD 10, and Dehalobacteriaceae decreased at GD 17 after TiO2 NPs exposure. Further phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) prediction indicated that the type 2 diabetes mellitus related genes were enhanced, and taurine metabolism was weakened at the second-trimester. Further study showed that the rats' fasting blood glucose levels significantly increased at GD 10 (P < 0.05) and GD 17 (P < 0.01) after exposure. Our study pointed out that TiO2 NPs induced the alteration of gut microbiota during pregnancy and increased the fasting blood glucose of pregnant rats, which might increase the potential risk of gestational diabetes of pregnant women.

Hypertension in Childhood Nephrotic Syndrome

Arterial hypertension (HTN) is commonly encountered by clinicians treating children with steroid sensitive (SSNS) and steroid resistant nephrotic syndrome (SRNS). Although the prevalence of HTN in SSNS is less documented than in SRNS, recent studies reported high prevalence in both. Studies have estimated the prevalence of HTN in different patient populations with NS to range from 8 to 59.1%. Ambulatory HTN, abnormalities in BP circadian rhythm, and measures of BP variability are prevalent in patients with NS. Multiple mechanisms and co-morbidities contribute to the pathophysiology of HTN in children with NS. Some contributing factors are known to cause acute and episodic elevations in blood pressure such as fluid shifts, sodium retention, and medication side effects (steroids, CNIs). Others are associated with chronic and more sustained HTN such as renal fibrosis, decreased GFR, and progression of chronic kidney disease. Children with NS are more likely to suffer from other cardiovascular disease risk factors, such as obesity, increased measures of arterial stiffness [increased carotid intima-media thickness (cIMT), endothelial dysfunction, increased pulse wave velocity (PWV)], impaired glucose metabolism, dyslipidemia, left ventricular hypertrophy (LVH), left ventricular dysfunction, and atherosclerosis. Those risk factors have been associated with premature death in adults. In this review on HTN in patients with NS, we will discuss the epidemiology and pathophysiology of hypertension in patients with NS, as well as management aspects of HTN in children with NS.

The Double-Edged Sword Effects of Maternal Nutrition in the Developmental Programming of Hypertension

Hypertension is a growing global epidemic. Developmental programming resulting in hypertension can begin in early life. Maternal nutrition status has important implications as a double-edged sword in the developmental programming of hypertension. Imbalanced maternal nutrition causes offspring's hypertension, while specific nutritional interventions during pregnancy and lactation may serve as reprogramming strategies to reverse programming processes and prevent the development of hypertension. In this review, we first summarize the human and animal data supporting the link between maternal nutrition and developmental programming of hypertension. This review also presents common mechanisms underlying nutritional programming-induced hypertension. This will be followed by studies documenting nutritional interventions as reprogramming strategies to protect against hypertension from developmental origins. The identification of ideal nutritional interventions for the prevention of hypertension development that begins early in life will have a lifelong impact, with profound savings in the global burden of hypertension.

Gut microbiota and inflammation in chronic kidney disease and their roles in the development of cardiovascular disease

The health and proper functioning of the cardiovascular and renal systems largely depend on crosstalk in the gut-kidney-heart/vessel triangle. Recent evidence suggests that the gut microbiota has an integral function in this crosstalk. Mounting evidence indicates that the development of chronic kidney and cardiovascular diseases follows chronic inflammatory processes that are affected by the gut microbiota via various immune, metabolic, endocrine, and neurologic pathways. Additionally, deterioration of the function of the cardiovascular and renal systems has been reported to disrupt the original gut microbiota composition, further contributing to the advancement of chronic cardiovascular and renal diseases. Considering the interaction between the gut microbiota and the renal and cardiovascular systems, we can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases.

Probiotics and Evidence-based Medicine: To All Involved: We have a Problem

The methods used to discern the structure (anatomy) and function (physiology) of the indigenous microbiota can be divided according to which aspect of the microbiota they can interrogate and are positioned accordingly. At the most basic level, methods can simply describe the community structure of the microbiota, that is, which taxa are present and in what relative amounts. Methods that investigate functional potential generally catalog the coding potential of individual members of the microbiota or the entire community (the metagenome). To measure function directly a catalog of the expressed microbial genes (the metatranscriptome) or the proteins or metabolites present in the microbiome environment must be generated. So, complexity in understanding the role of microbiota is quite rejecting the interested clinician. Evidence-based medicine can offer an answer suggesting strict definition of populations, measurement techniques, and external validity.

Influence of dietary protein on Dahl salt-sensitive hypertension: a potential role for gut microbiota

High blood pressure affects 1.39 billion adults across the globe and is the leading preventable cause of death worldwide. Hypertension is a multifaceted disease with known genetic and environmental factors contributing to its progression. Our studies utilizing the Dahl salt-sensitive (SS) rat have demonstrated the remarkable influence of dietary protein and maternal environment on the development of hypertension and renal damage in response to high salt. There is growing interest in the relationship between the microbiome and hypertension, with gut dysbiosis being correlated to a number of pathologies. This review summarizes the current literature regarding the interplay among dietary protein, the gut microbiota, and hypertension. These studies may provide insight into the effects we have observed between diet and hypertension in Dahl SS rats and, we hope, lead to new perspectives where potential dietary interventions or microbiota manipulations could serve as plausible therapies for hypertension.

Suboptimal community growth mediated through metabolite crossfeeding promotes species diversity in the gut microbiota

The gut microbiota represent a highly complex ecosystem comprised of approximately 1000 species that forms a mutualistic relationship with the human host. A critical attribute of the microbiota is high species diversity, which provides system robustness through overlapping and redundant metabolic capabilities. The gradual loss of bacterial diversity has been associated with a broad array of gut pathologies and diseases including malnutrition, obesity, diabetes and inflammatory bowel disease. We formulated an in silico community model of the gut microbiota by combining genome-scale metabolic reconstructions of 28 representative species to explore the relationship between species diversity and community growth. While the individual species offered a broad range of metabolic capabilities, communities optimized for maximal growth on simulated Western and high-fiber diets had low diversities and imbalances in short-chain fatty acid (SCFA) synthesis characterized by acetate overproduction. Community flux variability analysis performed with the 28-species model and a reduced 20-species model suggested that enhanced species diversity and more balanced SCFA production were achievable at suboptimal growth rates. We developed a simple method for constraining species abundances to sample the growth-diversity tradeoff and used the 20-species model to show that tradeoff curves for Western and high-fiber diets resembled Pareto-optimal surfaces. Compared to maximal growth solutions, suboptimal growth solutions were characterized by higher species diversity, more balanced SCFA synthesis and lower exchange rates of crossfed metabolites between more species. We hypothesized that modulation of crossfeeding relationships through host-microbiota interactions could be an important means for maintaining species diversity and suggest that community metabolic modeling approaches that allow multiobjective optimization of growth and diversity are needed for more realistic simulation of complex communities.

Understanding the Representative Gut Microbiota Dysbiosis in Metformin-Treated Type 2 Diabetes Patients Using Genome-Scale Metabolic Modeling

Dysbiosis in the gut microbiome composition may be promoted by therapeutic drugs such as metformin, the world’s most prescribed antidiabetic drug. Under metformin treatment, disturbances of the intestinal microbes lead to increased abundance of Escherichia spp., Akkermansia muciniphila, Subdoligranulum variabile and decreased abundance of Intestinibacter bartlettii. This alteration may potentially lead to adverse effects on the host metabolism, with the depletion of butyrate producer genus. However, an increased production of butyrate and propionate was verified in metformin-treated Type 2 diabetes (T2D) patients. The mechanisms underlying these nutritional alterations and their relation with gut microbiota dysbiosis remain unclear. Here, we used Genome-scale Metabolic Models of the representative gut bacteria Escherichia spp., I. bartlettii, A. muciniphila, and S. variabile to elucidate their bacterial metabolism and its effect on intestinal nutrient pool, including macronutrients (e.g., amino acids and short chain fatty acids), minerals and chemical elements (e.g., iron and oxygen). We applied flux balance analysis (FBA) coupled with synthetic lethality analysis interactions to identify combinations of reactions and extracellular nutrients whose absence prevents growth. Our analyses suggest that Escherichia sp. is the bacteria least vulnerable to nutrient availability. We have also examined bacterial contribution to extracellular nutrients including short chain fatty acids, amino acids, and gasses. For instance, Escherichia sp. and S. variabile may contribute to the production of important short chain fatty acids (e.g., acetate and butyrate, respectively) involved in the host physiology under aerobic and anaerobic conditions. We have also identified pathway susceptibility to nutrient availability and reaction changes among the four bacteria using both FBA and flux variability analysis. For instance, lipopolysaccharide synthesis, nucleotide sugar metabolism, and amino acid metabolism are pathways susceptible to changes in Escherichia sp. and A. muciniphila. Our observations highlight important commensal and competing behavior, and their association with cellular metabolism for prevalent gut microbes. The results of our analysis have potential important implications for development of new therapeutic approaches in T2D patients through the development of prebiotics, probiotics, or postbiotics.

Studying microbial functionality within the gut ecosystem by systems biology

Humans are not autonomous entities. We are all living in a complex environment, interacting not only with our peers, but as true holobionts; we are also very much in interaction with our coexisting microbial ecosystems living on and especially within us, in the intestine. Intestinal microorganisms, often collectively referred to as intestinal microbiota, contribute significantly to our daily energy uptake by breaking down complex carbohydrates into simple sugars, which are fermented to short-chain fatty acids and subsequently absorbed by human cells. They also have an impact on our immune system, by suppressing or enhancing the growth of malevolent and beneficial microbes. Our lifestyle can have a large influence on this ecosystem. What and how much we consume can tip the ecological balance in the intestine. A "western diet" containing mainly processed food will have a different effect on our health than a balanced diet fortified with pre- and probiotics. In recent years, new technologies have emerged, which made a more detailed understanding of microbial communities and ecosystems feasible. This includes progress in the sequencing of PCR-amplified phylogenetic marker genes as well as the collective microbial metagenome and metatranscriptome, allowing us to determine with an increasing level of detail, which microbial species are in the microbiota, understand what these microorganisms do and how they respond to changes in lifestyle and diet. These new technologies also include the use of synthetic and in vitro systems, which allow us to study the impact of substrates and addition of specific microbes to microbial communities at a high level of detail, and enable us to gather quantitative data for modelling purposes. Here, we will review the current state of microbiome research, summarizing the computational methodologies in this area and highlighting possible outcomes for personalized nutrition and medicine.

Microbiota metabolites: Pivotal players of cardiovascular damage in chronic kidney disease

In chronic kidney disease (CKD), cardiovascular (CV) damage is present in parallel which leads to an increased risk of CV disease. Both traditional and non-traditional risk factors contribute to CV damage in CKD. The systemic role of the microbiota as a central player in the pathophysiology of many organs is progressively emerging in the literature: the microbiota is indeed involved in a complex, bi-directional network between many organs, including the kidney and heart connection, although many of these relationships still need to be elucidated through in-depth mechanistic studies. The aim of this review is to provide evidence that microbiota metabolites influence non-traditional risk factors, such as inflammation and endothelial dysfunction in CKD-associated CV damage. Here, we report our current understanding and hypotheses on the gut-kidney and gut-heart axes and provide details on the potential mechanisms mediated by microbial metabolites. More specifically, we summarize some novel hypotheses linking the microbiota to blood pressure regulation and hypertension. We also emphasise the idea that the nutritional management of CKD should be redesigned and include the new findings from research on the intrinsic plasticity of the microbiota and its metabolites in response to food intake. The need is felt to integrate the classical salt and protein restriction approach for CKD patients with foods that enhance intestinal wellness. Finally, we discuss the new perspectives, especially the importance of taking care of the microbiota in order to prevent the risk of developing CKD and hypertension, as well as the still not tested but very promising CKD innovative treatments, such as postbiotic supplementation and bacteriotherapy. This interesting area of research offers potential complementary approaches to the management of CKD and CV damage assuming that the causal mechanisms underlying the gut-kidney and gut-heart axes are clarified. This will pave the way to the design of new personalized therapies targeting gut microbiota.

Gut microbiota in kidney disease and hypertension

The human gut microbiota is being composed of more than one hundred trillion microbial cells, including aerobic and anaerobic species as well as gram-positive and negative species. Animal based evidence suggests that the change of normal gut microbiota is responsible for several clinical implications including blood pressure increase and kidney function reduction. Trimethylamine-N-Oxide, short-chain fatty acids and inflammatory factors are originated from the gut microbes and may induce changes in arteries, kidneys and blood pressure. Prebiotics and probiotics change the gut microbiota and may reduce high blood pressure and ameliorate chronic kidney disease suggesting a new treatment target in patients for the initial stages of hypertension concomitant with other life style changes such as increased physical exercise and weight reduction to reduce cardiovascular disease complications.

Gut microbiota, hypertension and chronic kidney disease: Recent advances

A large number of different microbial species populates intestine. Extensive research has studied the entire microbial population and their genes (microbiome) by using metagenomics, metatranscriptomics and metabolomic analysis. Studies suggest that the imbalances of the microbial community causes alterations in the intestinal homeostasis, leading to repercussions on other systems: metabolic, nervous, cardiovascular, immune. These studies have also shown that alterations in the structure and function of the gut microbiota play a key role in the pathogenesis and complications of Hypertension (HTN) and Chronic Kidney Disease (CKD). Increased blood pressure (BP) and CKD are two leading risk factors for cardiovascular disease and their treatment represents a challenge for the clinicians. In this Review, we discuss mechanisms whereby gut microbiota (GM) and its metabolites act on downstream cellular targets to contribute to the pathogenesis of HTN and CKD, and potential therapeutic implications.

Bridging the Gap between Gut Microbial Dysbiosis and Cardiovascular Diseases

The human gut is heavily colonized by a community of microbiota, primarily bacteria, that exists in a symbiotic relationship with the host and plays a critical role in maintaining host homeostasis. The consumption of a high-fat (HF) diet has been shown to induce gut dysbiosis and reduce intestinal integrity. Recent studies have revealed that dysbiosis contributes to the progression of cardiovascular diseases (CVDs) by promoting two major CVD risk factors-atherosclerosis and hypertension. Imbalances in host-microbial interaction impair homeostatic mechanisms that regulate health and can activate multiple pathways leading to CVD risk factor progression. Dysbiosis has been implicated in the development of atherosclerosis through metabolism-independent and metabolite-dependent pathways. This review will illustrate how these pathways contribute to the various stages of atherosclerotic plaque progression. In addition, dysbiosis can promote hypertension through vascular fibrosis and an alteration of vascular tone. As CVD is the number one cause of death globally, investigating the gut microbiota as a locus of intervention presents a novel and clinically relevant avenue for future research, with vast therapeutic potential.