Pathophysiology and genetics of salt-sensitive hypertension

Silent Effects of High Salt: Risks Beyond Hypertension and Body's Adaptation to High Salt

Hypertension is a major contributor to heart disease, renal failure, and stroke. High salt is one of the significant risk factors associated with the onset and persistence of hypertension. Experimental and observational studies have confirmed cardiovascular and non-cardiovascular detrimental effects associated with chronic intake of high salt. Because of convenience and present urban lifestyles, consumption of fast food has led to daily salt intake above the recommended level by the World Health Organization. This study provides an understanding of the body regulatory mechanisms that maintain sodium homeostasis under conditions of high salt intake, without health consequences, and how these mechanisms adapt to chronic high salt load, leading to adverse cardiovascular, renal, and non-cardiovascular outcomes. Recent research has identified several mechanisms through which high sodium intake contributes to hypertension. Of them, heightened renin-angiotensin-aldosterone and sympathetic activity associated with impaired pressure diuresis and natriuresis and decreased renal excretory response are reported. Additionally, there is the possibility of endothelial and nitric oxide dysfunction leading to vascular remodeling. These changes raise cardiac output and peripheral vascular resistance. Knowing how these collective mechanisms adapt to chronic intakes of high salt helps develop effective therapeutic policies to fight salt-induced hypertension.

A comprehensive review on cardiovascular disorders development due to salt intake: an emphasis on policy implementation

Excessive salt consumption has been linked with the emergence of hypertension, which further leads to cardiovascular disease development among other medical conditions. This has resulted in leading world institutions such as the WHO coming up with relevant plans to minimize its use. Lower-middle-income countries (LMICs) have greatest burden of noncommunicable diseases (NCDs), with hypertension being a common condition. Reduction of salt intake is a great control measure in minimizing the rise in prevalence of hypertension or cardiovascular diseases. Many countries have agreed and even formulated their salt reduction policies as recommended by the WHO, however, the challenge is widely noted in implementation. Thus, few countries have been able to achieve the global WHO recommended standards of daily salt intake. Salt is the main source of sodium in our diets, which is an essential component responsible for the balance of the extracellular fluid volume but may lead to salt-induced hypertension when used excessively. The achievement of salt reduction is predicated on multiple factors such as knowledge, attitude and practice of the public. Therefore, localizing interventions with strategies such as public media campaigns, reformulation of processed foods (mandatory and voluntary) and front-of-packaging labelling awareness. Some of the reasons for failure in implementation include economic challenges, lack of visionary leadership, stakeholder struggles and poor planning and execution of strategies. This review aims to elaborate on the development of cardiovascular diseases or hypertension due to salt usage and the recent advancement regarding salt reduction policies. Further, we assess the need for proper implementation with the United Kingdom as a case study. In conclusion, most governments have made the right decisions in developing or recommending salt reduction strategies to the food industry. However, more focus is needed to ensure effective implementation of the plans.

The impact of dietary sodium and fructose on renal sodium handling and blood pressure in healthy adults

Increased dietary sodium is linked to hypertension, but most young adults display "sodium-resistant" blood pressure (BP), meaning BP is not elevated with sodium loading. In sodium-resistant rodents, fructose induces salt-sensitive BP via increased renal sodium reabsorption. Therefore, we tested the impact of fructose and sodium on renal sodium handling and BP in healthy adults, hypothesizing that their combination would impair sodium excretion and increase BP. Thirty-six participants enrolled in a randomized, double-blind, crossover trial involving three diets varying in fructose and sodium. On day 7, participants wore ambulatory BP monitors and collected 24-h urine. Although high sodium increased urinary sodium excretion, excretion was 15% lower with high fructose plus high salt versus high salt alone (235.1 ± 85.0 vs. 277.9 ± 121.2 mmol/24 h, p = 0.05). Compared to the recommended diet, high salt alone did not significantly change 24 h. MAP; however, high fructose plus high salt modestly raised 24 h MAP (81 ± 6 vs. 84 ± 7 mmHg, p = 0.03). High fructose and high salt increased serum interleukin-6 concentrations compared to the recommended diet (0.31 ± 0.2 vs. 0.24 ± 0.19 pg/mL, p = 0.04). These findings suggest that increased sodium and fructose alter renal sodium handling and BP in young adults.

Salt sensitivity of blood pressure: mechanisms and sex-specific differences

Salt sensitivity of blood pressure (SSBP) is an independent risk factor for cardiovascular disease in individuals with or without hypertension. However, the mechanisms and management of SSBP remain unclear, mainly because the diagnosis of this condition relies on salt loading-depletion protocols that are not feasible in the clinic. The prevalence of hypertension is lower in premenopausal women than in men, but this sex-specific difference is reversed after menopause. Whether excessive SSBP in women at any age contributes to this reversal is unknown, but many clinical studies that have rigorously assessed for SSBP using salt loading-depletion protocols have confirmed that SSBP is more prevalent in women than in men, including during premenopausal age. In this Review, we discuss sex-specific mechanisms of SSBP. We describe sex-related differences in renal transporters, hypertensive pregnancy, SSBP in autoimmune disorders and mitogen-activated protein kinase signalling pathways, and highlight limitations and lessons learned from Dahl salt-sensitive rat models.

Aging and sex differences in salt sensitivity of blood pressure

Salt sensitivity of blood pressure (SSBP) is a complex physiological trait characterized by changes in blood pressure in response to dietary salt intake. Aging introduces an additional layer of complexity to the pathophysiology of SSBP, with mitochondrial dysfunction, epigenetic modifications, and alterations in gut microbiota emerging as critical factors. Despite advancements in understanding these mechanisms, the processes driving increased salt sensitivity with age and their differential impacts across sexes remain unclear. This review explores the current understanding of salt sensitivity, delving into its underlying mechanisms, the role of inflammation, and the influence of aging and sex differences on these processes. We also aim to provide insights into the multifaceted nature of salt sensitivity and its implications for personalized treatment strategies in hypertension management.

Sodium, the Vascular Endothelium, and Hypertension: A Narrative Review of Literature

The vascular endothelium and its endothelial glycocalyx contribute to the protection of the endothelial cells from exposure to high levels of sodium and help these structures maintain normal function by regulating vascular permeability due to its buffering effect. The endothelial glycocalyx has negative surface charges that bind sodium and limit sodium entry into cells and the interstitial space. High sodium levels can disrupt this barrier and allow the movement of sodium into cells and extravascular fluid. This can generate reactive oxygen species that inhibit nitric oxide production. This leads to vasospasm and increases intravascular pressures. Overtime vascular remodeling occurs, and this changes the anatomy of blood vessels, their intrinsic stiffness, and their response to vasodilators and results in hypertension. Patients with increased salt sensitivity are potentially at more risk for this sequence of events. Studies on the degradation of the glycocalyx provide insight into the pathogenesis of clinical disorders with vascular involvement, but there is limited information available in the context of higher concentrations of sodium. Data on higher intake of sodium and the imbalance between nitric oxide and reactive oxygen species have been obtained in experimental studies and provide insights into possible outcomes in humans. The current western diet with sodium intake above recommended levels has led to the assessment of sodium sensitivity, which has been used in different populations and could become a practical tool to evaluate patients. This would potentially allow more focused recommendations regarding salt intake. This review will consider the structure of the vascular endothelium, its components, the effect of sodium on it, and the use of the salt blood test mini.

Salt-sensitive hypertension in GR mutant rats is associated with altered plasma polyunsaturated fatty acid levels and aortic vascular reactivity

In humans, glucocorticoid resistance is attributed to mutations in the glucocorticoid receptor (GR). Most of these mutations result in decreased ligand binding, transactivation, and/or translocation, albeit with normal protein abundances. However, there is no clear genotype‒phenotype relationship between the severity or age at disease presentation and the degree of functional loss of the receptor. Previously, we documented that a GR+/- rat line developed clinical features of glucocorticoid resistance, namely, hypercortisolemia, adrenal hyperplasia, and salt-sensitive hypertension. In this study, we analyzed the GR+/em4 rat model heterozygously mutant for the deletion of exon 3, which encompasses the second zinc finger, including the domains of DNA binding, dimerization, and nuclear localization signals. On a standard diet, mutant rats exhibited a trend toward increased corticosterone levels and a normal systolic blood pressure and heart rate but presented with adrenal hyperplasia. They exhibited increased adrenal soluble epoxide hydroxylase (sEH), favoring an increase in less active polyunsaturated fatty acids. Indeed, a significant increase in nonactive omega-3 and omega-6 polyunsaturated fatty acids, such as 5(6)-DiHETrE or 9(10)-DiHOME, was observed with advanced age (10 versus 5 weeks old) and following a switch to a high-salt diet accompanied by salt-sensitive hypertension. In thoracic aortas, a reduced soluble epoxide hydrolase (sEH) protein abundance resulted in altered vascular reactivity upon a standard diet, which was blunted upon a high-salt diet. In conclusion, mutations in the GR affecting the ligand-binding domain as well as the dimerization domain resulted in deregulated GR signaling, favoring salt-sensitive hypertension in the absence of obvious mineralocorticoid excess.

A novel mouse model recapitulates the effects of rs2254524 variant in the lanosterol synthase gene on salt sensitivity and organ damage

OBJECTIVE

The blood pressure (BP) response to salt intake (salt sensitivity) shows great variability among individuals and is more frequent in hypertensive patients. Elevated levels of the steroid hormone Endogenous Ouabain (EO) are associated with hypertension (HT) and salt sensitivity. The lanosterol synthase gene ( LSS ) plays a key role in the biosynthesis of steroids and its rs2254524 variant (Val642Leu) is linked to salt sensitivity in humans. This study aims to investigate the pathophysiological significance of the Lss missense variation in a new knock-in mouse model of salt-sensitive HT onset.

METHODS

We generated a mouse model carrying the murine homolog (Val643Leu) of the human LSS variant. C57BL/6N LssV643L/V643L mice were fed different NaCl diets (low-salt, LSD; normal-salt, NSD; high-salt, HSD) and were characterized at functional, histological, and molecular levels.

RESULTS

At baseline, mutant mice showed an enlarged kidney compared to the wild-type (WT) counterpart, but the Lss V643L variant did not affect EO biosynthesis nor systolic BP at 3 and 12 months. In HSD, we observed an increased systolic BP only in 12-month-old LssV643L/V643L mice, compared to NSD. Moreover, only the HSD LssV643L/V643L mice showed cardiac hypertrophy and a higher incidence of cardiac fibrosis compared to WT at 12 months. Finally, the Lss mRNA level was differentially regulated by HSD in the adrenal gland, liver, and heart of LssV643L/V643L mice compared to WT.

CONCLUSIONS

The novel Lss mouse model resembles the salt-sensitive HT phenotype observed in hypertensive patients and provides a good model of salt-sensitive HT and HT-mediated organ damage.

Research hotspots and trends regarding microRNAs in hypertension: a bibliometric analysis

To investigate the research levels, hotspots, and development trends regarding microRNAs in hypertension, this study conducted a visual analysis of studies on miRNA in hypertension based on the Web of Science core collection database using CiteSpace and VOSviewer analysis software along with literature from 2005-2023 as information data. Using citation frequency, centrality, and starting year as metrics, this study analyzed the research objects. It revealed the main research bodies and hotspots and evaluated the sources of literature and the distribution of knowledge from journals and authors. Finally, the potential research directions for miRNAs in hypertension are discussed. The results showed that the research field is in a period of vigorous development, and scholars worldwide have shown strong interest in this research field. A comprehensive summary and analysis of the current research status and application trends will prove beneficial for the advancement of this field.

How PPAR-alpha mediated inflammation may affect the pathophysiology of chronic kidney disease

Chronic kidney disease (CKD) is a major risk factor for death in adults. Inflammation plays a role in the pathogenesis of CKD, but the mechanisms are poorly understood. Peroxisome proliferator-activated receptor alpha (PPAR-α) is a nuclear receptor and one of the three members (PPARα, PPARβ/δ, and PPARγ) of the PPARs that plays an important role in ameliorating pathological processes that accelerate acute and chronic kidney disease. Although other PPARs members are well studied, the role of PPAR-α is not well described and its role in inflammation-mediated chronic disease is not clear. Herein, we review the role of PPAR-α in chronic kidney disease with implications for the immune system.

Revisiting sex as a biological variable in hypertension research

Half of adults in the United States have hypertension as defined by clinical practice guidelines. Interestingly, women are generally more likely to be aware of their hypertension and have their blood pressure controlled with treatment compared with men, yet hypertension-related mortality is greater in women. This may reflect the fact that the female sex remains underrepresented in clinical and basic science studies investigating the effectiveness of therapies and the mechanisms controlling blood pressure. This Review provides an overview of the impact of the way hypertension research has explored sex as a biological variable (SABV). Emphasis is placed on epidemiological studies, hypertension clinical trials, the genetics of hypertension, sex differences in immunology and gut microbiota in hypertension, and the effect of sex on the central control of blood pressure. The goal is to offer historical perspective on SABV in hypertension, highlight recent studies that include SABV, and identify key gaps in SABV inclusion and questions that remain in the field. Through continued awareness campaigns and engagement/education at the level of funding agencies, individual investigators, and in the editorial peer review system, investigation of SABV in the field of hypertension research will ultimately lead to improved clinical outcomes.

Zinc deficiency induces hypertension by paradoxically amplifying salt sensitivity under high salt intake in mice

BACKGROUND

Hypertension is one of the major etiologies that cause chronic kidney disease (CKD) and can exacerbate kidney dysfunction. Zinc is an essential trace element playing a role in blood pressure regulation, and zinc deficiency, a common comorbidity in patients with CKD, can cause hypertension. However, the precise mechanism underlying zinc deficiency-induced hypertension is unknown. Sodium (Na+) retention due to inappropriate Na+ reabsorption in the renal tubule is the principal pathophysiology of hypertension. Therefore, this study aimed to investigate the association between zinc deficiency and salt sensitivity.

METHODS

Adult mice were fed a zinc-adequate (ZnA) or zinc-deficient (ZnD) diet combined with/without high salt in drinking water (HS) for 4 weeks (n = 6 each). Changes in blood pressure, urinary sodium excretion, and the expressions of the proximal tubular Na+ transporter, Na+/H+ exchanger 3 (NHE3), which mostly contributes to filtered Na+ reabsorption and the downstream Na+-Cl- transporter (NCC) were analyzed.

RESULTS

Urinary Na+ excretion significantly increased in ZnD mice, indicating that zinc deficiency causes natriuresis. NHE3 expressions were significantly suppressed, whereas NCC was upregulated in ZnD mice. Interestingly, the combination of high salt and ZnD diet (HS-ZnD) reversed the urinary Na+ loss. The NCC remained activated and NHE3 expressions paradoxically increased in HS-ZnD mice compared with those fed the combination of high salt and ZnA diet. In addition, blood pressure significantly increased only in HS-ZnD mice.

CONCLUSION

The combination of zinc deficiency and high salt causes hypertension. Zinc is associated with salt-sensitivity, potentially through NHE3 and NCC regulation.

Hypertension in an ageing population: Diagnosis, mechanisms, collateral health risks, treatments, and clinical challenges

Ageing population is considerably increasing worldwide, which is considered to reflect an improved quality of life. However, longevity in the human lifespan has increased the burden of late-life illnesses including cancer, neurodegeneration, and cardiovascular dysfunction. Of these, hypertension is the most common condition with huge health risks, with an increased prevalence among the elderly. In this review, we outline the current guidelines for defining hypertension and examine the detailed mechanisms underlying the relationship between hypertension and ageing-related outcomes, including sodium sensitivity, arterial stiffness, endothelial dysfunction, isolated systolic hypertension, white coat effect, and orthostatic hypertension. As hypertension-related collateral health risk increases among the elderly, the available management strategies are necessary to overcome the clinical treatment challenges faced among elderly population. To improve longevity and reduce adverse health effects, potential approaches producing crucial information into new era of medicine should be considered in the prevention and treatment of hypertension among elderly population. This review provides an overview of mechanisms underlying hypertension and its related collateral health risk in elderly population, along with multiple approaches and management strategies to improve the clinical challenges among elderly population.

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.

Immune and inflammatory mechanisms in hypertension

Hypertension is a global health problem, with >1.3 billion individuals with high blood pressure worldwide. In this Review, we present an inflammatory paradigm for hypertension, emphasizing the crucial roles of immune cells, cytokines and chemokines in disease initiation and progression. T cells, monocytes, macrophages, dendritic cells, B cells and natural killer cells are all implicated in hypertension. Neoantigens, the NLRP3 inflammasome and increased sympathetic outflow, as well as cytokines (including IL-6, IL-7, IL-15, IL-18 and IL-21) and a high-salt environment, can contribute to immune activation in hypertension. The activated immune cells migrate to target organs such as arteries (especially the perivascular fat and adventitia), kidneys, the heart and the brain, where they release effector cytokines that elevate blood pressure and cause vascular remodelling, renal damage, cardiac hypertrophy, cognitive impairment and dementia. IL-17 secreted by CD4+ T helper 17 cells and γδ T cells, and interferon-γ and tumour necrosis factor secreted by immunosenescent CD8+ T cells, exert crucial effector roles in hypertension, whereas IL-10 and regulatory T cells are protective. Effector mediators impair nitric oxide bioavailability, leading to endothelial dysfunction and increased vascular contractility. Inflammatory effector mediators also alter renal sodium and water balance and promote renal fibrosis. These mechanisms link hypertension with obesity, autoimmunity, periodontitis and COVID-19. A comprehensive understanding of the immune and inflammatory mechanisms of hypertension is crucial for safely and effectively translating the findings to clinical practice.

Epigenetics of hypertension as a risk factor for the development of coronary artery disease in type 2 diabetes mellitus

Hypertension, a multifaceted cardiovascular disorder influenced by genetic, epigenetic, and environmental factors, poses a significant risk for the development of coronary artery disease (CAD) in individuals with type 2 diabetes mellitus (T2DM). Epigenetic alterations, particularly in histone modifications, DNA methylation, and microRNAs, play a pivotal role in unraveling the complex molecular underpinnings of blood pressure regulation. This review emphasizes the crucial interplay between epigenetic attributes and hypertension, shedding light on the prominence of DNA methylation, both globally and at the gene-specific level, in essential hypertension. Additionally, histone modifications, including acetylation and methylation, emerge as essential epigenetic markers linked to hypertension. Furthermore, microRNAs exert regulatory influence on blood pressure homeostasis, targeting key genes within the aldosterone and renin-angiotensin pathways. Understanding the intricate crosstalk between genetics and epigenetics in hypertension is particularly pertinent in the context of its interaction with T2DM, where hypertension serves as a notable risk factor for the development of CAD. These findings not only contribute to the comprehensive elucidation of essential hypertension but also offer promising avenues for innovative strategies in the prevention and treatment of cardiovascular complications, especially in the context of T2DM.

Dietary High Salt Intake Exacerbates SGK1-Mediated T Cell Pathogenicity in L-NAME/High Salt-Induced Hypertension

Sodium chloride (NaCl) activates Th17 and dendritic cells in hypertension by stimulating serum/glucocorticoid kinase 1 (SGK1), a sodium sensor. Memory T cells also play a role in hypertension by infiltrating target organs and releasing proinflammatory cytokines. We tested the hypothesis that the role of T cell SGK1 extends to memory T cells. We employed mice with a T cell deletion of SGK1, SGK1fl/fl × tgCD4cre mice, and used SGK1fl/fl mice as controls. We treated the mice with L-NAME (0.5 mg/mL) for 2 weeks and allowed a 2-week washout interval, followed by a 3-week high-salt (HS) diet (4% NaCl). L-NAME/HS significantly increased blood pressure and memory T cell accumulation in the kidneys and bone marrow of SGK1fl/fl mice compared to knockout mice on L-NAME/HS or groups on a normal diet (ND). SGK1fl/fl mice exhibited increased albuminuria, renal fibrosis, and interferon-γ levels after L-NAME/HS treatment. Myography demonstrated endothelial dysfunction in the mesenteric arterioles of SGK1fl/fl mice. Bone marrow memory T cells were adoptively transferred from either mouse strain after L-NAME/HS administration to recipient CD45.1 mice fed the HS diet for 3 weeks. Only the mice that received cells from SGK1fl/fl donors exhibited increased blood pressure and renal memory T cell infiltration. Our data suggest a new therapeutic target for decreasing hypertension-specific memory T cells and protecting against hypertension.

The sympathetic nervous system in heart failure revisited

Several attempts have been made, by the scientific community, to develop a unifying hypothesis that explains the clinical syndrome of heart failure (HF). The currently widely accepted neurohormonal model has substituted the cardiorenal and the cardiocirculatory models, which focused on salt-water retention and low cardiac output/peripheral vasoconstriction, respectively. According to the neurohormonal model, HF with eccentric left ventricular (LV) hypertrophy (LVH) (systolic HF or HF with reduced LV ejection fraction [LVEF] or HFrEF) develops and progresses because endogenous neurohormonal systems, predominantly the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS), exhibit prolonged activation following the initial heart injury exerting deleterious hemodynamic and direct nonhemodynamic cardiovascular effects. However, there is evidence to suggest that SNS overactivity often preexists HF development due to its association with HF risk factors, is also present in HF with preserved LVEF (diastolic HF or HFpEF), and that it is linked to immune/inflammatory factors. Furthermore, SNS activity in HF may be augmented by coexisting noncardiac morbidities and modified by genetic factors and demographics. The purpose of this paper is to provide a contemporary overview of the complex associations between SNS overactivity and the development and progression of HF, summarize the underlying mechanisms, and discuss the clinical implications as they relate to therapeutic interventions mitigating SNS overactivity.

High salt-induced morphological and glycocalyx remodeling of human vascular smooth muscle cells is reversible but induces a high sodium salt-like sensitive memory

Our recent work showed that short-term treatment (1-2 days) with high sodium salt had no effect on the morphology of human vascular smooth muscle cells (hVSMCs). However, chronic (long-term treatment, 6-16 days) high sodium salt (CHSS) induced hypertrophy and decreased the relative density of the glycocalyx in hVSMCs. Whether this CHSS effect is reversible at both the morphological and the intracellular calcium and sodium levels is unknown. In the present study, we tested the hypothesis that the effect of CHSS on the morphological and functional levels of hVSMCs is reversible. However, it induced an irreversible increase in the sensitivity of the cells following short-term treatment with high extracellular Na+. We tested the effects of the removal of CHSS treatment on the morphology and intracellular sodium and calcium of hVSMCs. Our results showed that restoring average sodium concentration (145 mM) modeled back the relative density of the glycocalyx, the intracellular resting calcium and sodium levels, and the whole cell and nuclear volumes of hVSMCs. In addition, it induced a permanent remodeling of hVSMCs' response to a short-term increase in the extracellular level of sodium salt by developing spontaneous cytosolic and nuclear calcium waves. Our results showed that CHSS is reversible at both the morphological and basal intracellular ionic levels. However, it maintained a high sensitivity to short-term elevation of extracellular sodium. These results suggest that even if chronic high salt is corrected, it induces a high sodium salt-like sensitive memory.

Sexual Dimorphic Interplays Between Gut Microbiota and Antihypertensive Drugs

PURPOSE OF THE REVIEW

The purpose of this study is to review the current literature regarding gut microbiota in blood pressure regulation and its interactions with antihypertensive drugs and to discuss how sex differences in gut microbiota contribute to sexual dimorphism of hypertension and treatment.

RECENT FINDINGS

The significance of gut microbiota in blood pressure regulation and hypertension etiology is growingly recognized. Targeting the dysbiotic microbiota is proposed to be a new therapeutic method. Recently, a few studies demonstrated that the gut microbiota is highly involved in the modulation of the efficacy of antihypertensive drugs, suggesting a novel mechanism by which gut microbiota plays a role in treatment-resistant hypertension. Furthermore, studies on sex differences in gut microbiota, etiology of hypertension, and sex bias in prescription of antihypertensive medications have revealed promising avenues in sexual dimorphism-based precision medicine. However, no scientific questions are ever raised on how sex differences in gut microbiota contribute to the sex specific responses of certain classes of antihypertensive drugs. Given the dynamics and complexity among individuals, precision medicine is proposed of great potential. We review current knowledge on the interactions between gut microbiota, hypertension, and antihypertensive drugs with an emphasis on sex as a crucial determinant. We propose that sex differences in gut microbiota be a research focus to advance our understanding of hypertension management.

Reducing the Sodium Intake of Patients With Chronic Kidney Disease Through Education and Estimating Salt Excretion: A Propensity Score Matching Analysis

BACKGROUND

Japanese people traditionally consume high quantities of salt. This study aimed to investigate the effects of educating patients with chronic kidney disease (CKD) on simple methods for reducing their daily dietary salt intake.

METHODS

This single-center, retrospective observational study included 115 outpatients with CKD at Kawashima Hospital (Tokushima, Japan). One physician routinely recommended that patients should reduce their salt intake and provided tips for salt restriction. The physician estimated the patients' daily salt intake using spot urine samples at each medical examination (education group; n = 61). The other physicians' outpatients only received dietary guidance on recommended salt intake (control group; n = 54). The estimated 24-hour urinary sodium excretion (24hUNaV) and 24-hour potassium excretion (24hUKV) were calculated using Tanaka's equation.

RESULTS

Estimated 24hUNaV was positively correlated with body mass index (BMI), estimated 24hUKV, and urinary Na/K ratio. The patients in the education group were younger and had a lower BMI, higher estimated glomerular filtration rate, and lower systolic blood pressure (SBP). Using 38 pairs of patients obtained by propensity score matching with these variables, estimated 24hUNaV, estimated 24hUKV, and diastolic blood pressure (DBP) after one year were significantly reduced in the education group.

CONCLUSION

A simple salt reduction education may reduce salt intake in outpatients with CKD.

Salt-Sensitive Hypertension: Mediation by Salt-Induced Hypervolemia and Phosphate-Induced Vascular Calcification

Preventing hypertension by restricting dietary salt intake, sodium chloride, is well established in public health policy, but a pathophysiological mechanism has yet to explain the controversial clinical finding that some individuals have a greater risk of hypertension from exposure to salt intake, termed salt-sensitive hypertension. The present perspective paper synthesizes interdisciplinary findings from the research literature and offers novel insights proposing that the pathogenesis of salt-sensitive hypertension is mediated by interaction of salt-induced hypervolemia and phosphate-induced vascular calcification. Arterial stiffness and blood pressure increase as calcification in the vascular media layer reduces arterial elasticity, preventing arteries from expanding to accommodate extracellular fluid overload in hypervolemia related to salt intake. Furthermore, phosphate has been found to be a direct inducer of vascular calcification. Reduction of dietary phosphate may help reduce salt-sensitive hypertension by lowering the prevalence and progression of vascular calcification. Further research should investigate the correlation of vascular calcification with salt-sensitive hypertension, and public health recommendations to prevent hypertension should encourage reductions of both sodium-induced hypervolemia and phosphate-induced vascular calcification.

Hypertensive heart disease: risk factors, complications and mechanisms

Hypertensive heart disease constitutes functional and structural dysfunction and pathogenesis occurring primarily in the left ventricle, the left atrium and the coronary arteries due to chronic uncontrolled hypertension. Hypertensive heart disease is underreported and the mechanisms underlying its correlates and complications are not well elaborated. In this review, we summarize the current understanding of hypertensive heart disease, we discuss in detail the mechanisms associated with development and complications of hypertensive heart disease especially left ventricular hypertrophy, atrial fibrillation, heart failure and coronary artery disease. We also briefly highlight the role of dietary salt, immunity and genetic predisposition in hypertensive heart disease pathogenesis.