Mechanism-based strategies to prevent salt sensitivity and salt-induced hypertension

Unraveling the gut microbiota's role in salt-sensitive hypertension: current evidences and future directions

The gut microbiota plays a pivotal role in both maintaining human health and in the pathogenesis of diseases. Recent studies have brought to light the significant correlation between gut microbiota and hypertension, particularly focusing on its role in the development and advancement of SSH, a subtype characterized by elevated blood pressure in response to high salt consumption. The complexity of SSH's etiology is notable, with dysbiosis of the gut microbiome identified as a crucial contributing factor. The gut microbiota participates in the occurrence and development of SSH by affecting the host's immune system, metabolic function, and neuromodulation. Investigations have demonstrated that the gut microbes regulate the development of SSH by regulating the TH17 axis and the activity of immune cells. Moreover, microbial metabolites, such as short-chain fatty acids, are implicated in blood pressure regulation and affect the development of SSH. There is evidence to show that the composition of the gut microbiome can be altered through prebiotic interventions so as to prevent and treat SSH. This review aims to concisely sum up the role of gut microbiota in SSH and to discuss pertinent therapeutic strategies and clinical implications, thereby providing a valuable reference for further research and clinical practice in this area.

Capsaicin pretreatment attenuates salt-sensitive hypertension by alleviating AMPK/Akt/Nrf2 pathway in hypothalamic paraventricular nucleus

Background

Long term hypertension seriously promotes target organ damage in the brain and heart, and has increasingly become serious public health problem worldwide. The anti-hypertensive effects of capsaicin has been reported, however, the role and mechanism of capsaicin within the brain on salt-induced hypertension have yet to be elucidated. This study aimed to verify the hypothesis that capsaicin attenuates salt-induced hypertension via the AMPK/Akt/Nrf2 pathway in hypothalamic paraventricular nucleus (PVN).

Methods

Dahl salt-sensitive (Dahl S) rats were used as animal model for the present study. Rats were randomly divided into four groups based on their dietary regimen (0.3% normal salt diet and 8% high salt diet) and treatment methods (infusion of vehicle or capsaicin in the PVN). Capsaicin was chronically administered in the PVN throughout the animal experiment phase of the study that lasted 6 weeks.

Results

Our results demonstrated that PVN pretreatment with capsaicin can slow down raise of the blood pressure elevation and heart rate (HR) of Dahl S hypertensive rats given high salt diet. Interestingly, the cardiac hypertrophy was significantly improved. Furthermore, PVN pretreatment with capsaicin induced decrease in the expression of mRNA expression of NADPH oxidase-2 (NOX2), inducible nitric oxide synthase (iNOS), NOX4, p-IKKβ and proinflammatory cytokines and increase in number of positive cell level for Nrf2 and HO-1 in the PVN of Dahl S hypertensive rats. Additionally, the protein expressions of phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase-B (p-AKT) were decreased, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were increased after the PVN pretreatment with capsaicin.

Conclusion

Capsaicin pretreatment attenuates salt-sensitive hypertension by alleviating AMPK/Akt/iNOS pathway in the PVN.

A review of the world's salt reduction policies and strategies - preparing for the upcoming year 2025

Excessive consumption of dietary sodium is a significant contributor to non-communicable diseases, including hypertension and cardiovascular disease. There is now a global consensus that regulating salt intake is among the most cost-effective measures for enhancing public health. More than half of the countries worldwide have implemented multiple strategies to decrease salt consumption. Nevertheless, a report on sodium intake reduction published by the World Health Organization revealed that the world is off-track to meet its targeted reduction of 30% by 2025. The global situation regarding salt reduction remains concerning. This review will center on domestic and international salt reduction policies, as well as diverse strategies, given the detrimental effects of excessive dietary salt intake and the existing global salt intake scenario. Besides, we used visualization software to analyze the literature related to salt reduction research in the last five years to explore the research hotspots in this field. Our objective is to enhance public awareness regarding the imperative of reducing salt intake and promoting the active implementation of diverse salt reduction policies.

Evaluating the Energy and Core Nutrients of Condiments in China

Condiments are a significant source of sodium in the diets of Chinese residents. This study aimed to analyze the nutrient content of China's major condiments and to provide support for setting the reference intake for condiments in order to take measures on salt reduction in China. Nutrition data for condiments were collected from the Database on Nutrition Labelling of Prepackaged Foods China in 2017-2022, and by online access to food composition databases from France, the UK, Belgium, and Japan. The analyses include 1510 condiments in China and 1565 related condiments in four countries, of which the descriptive indicators were examined such as median, IQR, and range. Cross-comparisons were made in terms of the difference between the content levels in five countries and the "WHO global sodium benchmarks". The results show that among the 15 types of condiments in China, sesame/peanut butter-based products have a relatively high content of energy, fat, and protein, namely, 2580 kJ/100 g, 50 g/100 g, and 22.2 g/100 g, respectively. In addition to salt, chicken extract/chicken powder, bouillon cubes, and soy sauce are also high in sodium. Furthermore, there were significant differences in the contents of energy and core nutrients across different products when benchmarking with similar condiments in the five countries (p < 0.001). The sodium content and fat content of some condiments are excessively high. Therefore, enhancing residents' consumption awareness and reducing the amount of condiments is of great significance for reducing China's per capita salt intake and promoting good health.

Novel mechanisms of salt-sensitive hypertension

A high dietary sodium-consumption level is considered the most important lifestyle factor that can be modified to help prevent an increase in blood pressure and the development of hypertension. Despite numerous studies over the past decades, the pathophysiology explaining why some people show a salt-sensitive blood pressure response and others do not is incompletely understood. Here, a brief overview of the latest mechanistic insights is provided, focusing on the mononuclear phagocytic system and inflammation, the gut-kidney axis, and epigenetics. The article also discusses the effects of 3 types of novel drugs on salt-sensitive hypertension-sodium-glucose cotransporter 2 inhibitors, nonsteroidal mineralocorticoid receptor antagonists, and aldosterone synthase inhibitors. The conclusion is that besides kidney-centered mechanisms, vasoconstrictor mechanisms are also relevant for both the understanding and treatment of this blood pressure phenotype.

Initiatives to Reduce the Content of Sodium in Food Products and Meals and Improve the Population's Health

Table salt is the main source of sodium (Na) in the human diet. Excessive supply of Na in a diet is strongly linked to many non-communicable human diseases, such as hypertension, obesity and stomach cancer. The World Health Organization recommends that daily intake of salt in adult diets should be kept below 5 g/person/day, which corresponds to 2 g Na/person/day. However, on average, adults consume about 9-10 g/person/day, and children and young people about 7-8 g/person/day. Initiatives to reduce salt intake include modifications of food composition in collaboration with the food industry, education of consumers, salt marking on foodstuff labels and taxation of salt. A need also exists to educate society so that they choose low-sodium products. In view of the food technology and amount of salt intake, the most important and the easiest change to make is to reduce the content of salt in baked goods. This paper analyses the results of surveys regarding strategies to reduce salt content in food products and considers multifaceted initiatives to reduce salt intake as a possible efficient method of improving the population's health status.

Dietary sodium, potassium intake, sodium-to-potassium ratio and risk of hypertension: a protocol for systematic review and dose-response meta-analysis of cohort studies

INTRODUCTION

Hypertension (HTN) is the leading cause of disease and death on a global scale. Diet's sodium and potassium levels may synergistically affect blood pressure. Currently, the sodium-to-potassium (Na/K) ratio is becoming a more reliable indicator. There has not been a systematic investigation of the dose-response relationship between dietary sodium, potassium, the Na/K ratio and the incidence of HTN based on the same study criteria. This study will conduct a thorough dose-response meta-analysis of cohort studies to estimate the effects of dietary sodium, potassium, and the Na/K ratio on the incidence of HTN to provide the most accurate reference for sodium and potassium intake.

METHODS AND ANALYSIS

We will identify all relevant prospective and retrospective cohort studies by searching PubMed, Embase and Web of Science (from inception until December 2022). Exposures are 24 hours urinary excretions, and the outcome is the incidence of HTN. Two researchers will perform the literature selection and data extraction separately. The Newcastle-Ottawa Scale will be used to evaluate the quality of the included studies. We will use both linear and non-linear regression models to investigate the dose-response relationship among different levels (≥3) of sodium, potassium, Na/K ratio intake and the incidence of HTN (OR/RR/HR). Subgroup and sensitivity analyses will be applied to assess the potential heterogeneity sources and examine the stability of the results. We will also evaluate heterogeneity across studies and publication bias. Stata V.15.0 and RevMan V.5.0 will be used for statistical analyses.

ETHICS AND DISSEMINATION

According to the Institutional Review Board/Independent Ethics Committee of the Guang'anmen Hospital of the China Academy of Chinese Medical Science, this systematic meta-analysis protocol does not require ethical approval or informed consent. This meta-analysis will be published in a scientific journal with peer reviews.

PROSPERO REGISTRATION NUMBER

CRD42022331203.