Inflammation and oxidative stress in salt sensitive hypertension; The role of the NLRP3 inflammasome

IRF5 Mediates Artery Inflammation in Salt-Sensitive Hypertension by Regulating STAT1 and STAT2 Phosphorylation to Increase ESM1 Transcription: Insights from Bioinformatics and Mechanistic Analysis

Salt-sensitive hypertension (SSH) is closely associated with arterial inflammation, yet its molecular mechanisms remain unclear. In this study, we utilized deoxycorticosterone acetate (DOCA)-salt-induced hypertensive mice, which exhibited elevated blood pressure and significant arterial inflammation. Single-cell RNA sequencing (scRNA-seq) identified interferon regulatory factor 5 (IRF5) and its downstream targets, signal transducer and activator of transcription (STAT), as key regulators of these inflammatory changes. In vivo, IRF5 levels were significantly elevated in the DOCA group, while STAT1 and STAT2 protein levels were comparable to those in the normal salt group. However, nuclear levels of phosphorylated STAT1 (pSTAT1) and phosphorylated STAT2 (pSTAT2) were markedly higher in the DOCA group. Furthermore, scRNA-seq analysis showed increased IRF5 expression in endothelial cells (ECs) in both human and mouse aorta samples. In vitro, IRF5 knockdown in artery ECs led to a reduction in nuclear pSTAT1 and pSTAT2 expression. These results suggest that IRF5 promotes STAT1 and STAT2 phosphorylation, enabling their nuclear translocation. Additionally, RNA sequencing indicated a positive correlation between endothelial cell-specific molecule 1 (ESM1) and STAT1/STAT2. Using the UCSC and JASPAR databases, we identified multiple binding sites for the STAT1::STAT2 dimer on the ESM1 promoter. Luciferase reporter assays revealed enhanced ESM1 transcription following pSTAT1::pSTAT2 binding, and pinpoint potential binding sites. Chromatin Immunoprecipitation Quantitative PCR (ChIP-qPCR) further confirmed the specific binding sites between the pSTAT1::pSTAT2 dimer and the ESM1 promoter. These findings highlight the critical role of the IRF5-pSTAT1::pSTAT2-ESM1 pathway in the pathogenesis of SSH and suggest potential therapeutic targets.

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.

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.

Epigenetic Regulation of Innate and Adaptive Immune Cells in Salt-Sensitive Hypertension

Access to excess dietary sodium has heightened the risk of cardiovascular diseases, particularly affecting individuals with salt sensitivity of blood pressure. Our research indicates that innate antigen-presenting immune cells contribute to rapid blood pressure increases in response to excess sodium intake. Emerging evidence suggests that epigenetic reprogramming, with subsequent transcriptional and metabolic changes, of innate immune cells allows these cells to have a sustained response to repetitive stimuli. Epigenetic mechanisms also steer T-cell differentiation in response to innate immune signaling. Immune cells respond to environmental and nutritional cues, such as salt, promoting epigenetic regulation changes. This article aims to identify and discuss the role of epigenetic mechanisms in the immune system contributing to salt-sensitive hypertension.

Angiotensin II Exposure In Vitro Reduces High Salt-Induced Reactive Oxygen Species Production and Modulates Cell Adhesion Molecules' Expression in Human Aortic Endothelial Cell Line

Background/Objectives: Increased sodium chloride (NaCl) intake led to leukocyte activation and impaired vasodilatation via increased oxidative stress in human/animal models. Interestingly, subpressor doses of angiotensin II (AngII) restored endothelium-dependent vascular reactivity, which was impaired in a high-salt (HS) diet in animal models. Therefore, the present study aimed to assess the effects of AngII exposure following high salt (HS) loading on endothelial cells' (ECs') viability, activation, and reactive oxygen species (ROS) production. Methods: The fifth passage of human aortic endothelial cells (HAECs) was cultured for 24, 48, and 72 h with NaCl, namely, the control (270 mOsmol/kg), HS320 (320 mOsmol/kg), and HS350 (350 mOsmol/kg). AngII was administered at the half-time of the NaCl incubation (10-4-10-7 mol/L). Results: The cell viability was significantly reduced after 24 h in the HS350 group and in all groups after longer incubation. AngII partly preserved the viability in the HAECs with shorter exposure and lower concentrations of NaCl. Intracellular hydrogen peroxide (H2O2) and peroxynitrite (ONOO-) significantly increased in the HS320 group following AngII exposure compared to the control, while it decreased in the HS350 group compared to the HS control. A significant decrease in superoxide anion (O2.-) formation was observed following AngII exposure at 10-5, 10-6, and 10-7 mol/L for both HS groups. There was a significant decrease in intracellular adhesion molecule 1 (ICAM-1) and endoglin expression in both groups following treatment with 10-4 and 10-5 mol/L of AngII. Conclusions: The results demonstrated that AngII significantly reduced ROS production at HS350 concentrations and modulated the viability, proliferation, and activation states in ECs.

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.

Recent updates on the influence of iron and magnesium on vascular, renal, and adipose inflammation and possible consequences for hypertension

The inflammatory status of the kidneys, vasculature, and perivascular adipose tissue (PVAT) has a significant influence on blood pressure and hypertension. Numerous micronutrients play an influential role in hypertension-driving inflammatory processes, and recent reports have provided bases for potential targeted modulation of these micronutrients to reduce hypertension. Iron overload in adipose tissue macrophages and adipocytes engenders an inflammatory environment and may contribute to impaired anticontractile signalling, and thus a treatment such as chelation therapy may hold a key to reducing blood pressure. Similarly, magnesium intake has proven to greatly influence inflammatory signalling and concurrent hypertension in both healthy animals and in a model for chronic kidney disease, demonstrating its potential clinical utility. These findings highlight the importance of further research to determine the efficacy of micronutrient-targeted treatments for the amelioration of hypertension and their potential translation into clinical application.

Deletion of Kcnj16 altered transcriptomic and metabolomic profiles of Dahl salt-sensitive rats

The inwardly rectifying K+ channel Kir5.1 (Kcnj16) is essential in renal salt handling and blood pressure control. However, the underlying mechanisms are not fully understood. Here, we integrated transcriptomics and metabolomics to comprehensively profile the changes in genes and metabolites in the Dahl salt-sensitive (SS) rat lacking Kcnj16 to identify potential mechanisms. Consistent with the phenotype of knockout (KO) rats, the transcriptomic profile predicted reduced blood pressure, kidney damage, and increased ion transport. Canonical pathway analysis suggested activation of metabolic-related pathways while suppression of immune response-related pathways in KO rats. Untargeted metabolomic analysis revealed different metabolic profiles between wild-type (WT) and KO rats. Integration of transcriptomic and metabolomic profiles suggested altered tricarboxylic acid (TCA) cycle, amino acid metabolism, and reactive oxygen species (ROS) metabolism that are related to SS hypertension. In conclusion, besides increased ion transport, our data suggest suppressed immune response-related and altered metabolic-related pathways of SS rats lacking Kir5.1.

Myeloid-Specific JAK2 Contributes to Inflammation and Salt Sensitivity of Blood Pressure

BACKGROUND

Salt sensitivity of blood pressure (SSBP), characterized by acute changes in blood pressure with changes in dietary sodium intake, is an independent risk factor for cardiovascular disease and mortality in people with and without hypertension. We previously found that elevated sodium concentration activates antigen-presenting cells (APCs), resulting in high blood pressure, but the mechanisms are unknown. Here, we hypothesized that APC-specific JAK2 (Janus kinase 2) through STAT3 (signal transducer and activator of transcription 3) and SMAD3 (small mothers against decapentaplegic homolog 3) contributes to SSBP.

METHODS

We performed bulk or single-cell transcriptomic analyses following in vitro monocytes exposed to high salt and in vivo high sodium treatment in humans using a rigorous salt-loading/depletion protocol to phenotype SSBP. We also used a myeloid cell-specific CD11c+ JAK2 knockout mouse model and measured blood pressure with radiotelemetry after N-omega-nitro-L-arginine-methyl ester and a high salt diet treatment. We used flow cytometry for immunophenotyping and measuring cytokine levels. Fluorescence in situ hybridization and immunohistochemistry were performed to spatially visualize the kidney's immune cells and cytokine levels. Echocardiography was performed to assess cardiac function.

RESULTS

We found that high salt treatment upregulates gene expression of the JAK/STAT/SMAD pathway while downregulating inhibitors of this pathway, such as suppression of cytokine signaling and cytokine-inducible SH2, in human monocytes. Expression of the JAK2 pathway genes mirrored changes in blood pressure after salt loading and depletion in salt-sensitive but not salt-resistant humans. Ablation of JAK2, specifically in CD11c+ APCs, attenuated salt-induced hypertension in mice with SSBP. Mechanistically, we found that SMAD3 acted downstream of JAK2 and STAT3, leading to increased production of highly reactive isolevuglandins and proinflammatory cytokine IL (interleukin)-6 in renal APCs, which activate T cells and increase production of IL-17A, IL-6, and TNF-α (tumor necrosis factor-alpha).

CONCLUSIONS

Our findings reveal the APC JAK2 signaling pathway as a potential target for the diagnosis and treatment of SSBP in humans.

Bile Acid Metabolism Analysis Provides Insights into Vascular Endothelial Injury in Salt-Sensitive Hypertensive Rats

As an unhealthy dietary habit, a high-salt diet can affect the body's endocrine system and metabolic processes. As one of the most important metabolites, bile acids can prevent atherosclerosis and reduce the risk of developing cardiovascular diseases. Therefore, in the present study, we aimed to reveal the bile acid metabolism changes in salt-sensitive hypertension-induced vascular endothelial injury. The model was established using a high-salt diet, and the success of this procedure was confirmed by detecting the levels of the blood pressure, vascular regulatory factors, and inflammatory factors. An evaluation of the histological sections of arterial blood vessels and kidneys confirmed the pathological processes in these tissues of experimental rats. Bile acid metabolism analysis was performed to identify differential bile acids between the low-salt diet group and the high-salt diet group. The results indicated that the high-salt diet led to a significant increase in blood pressure and the levels of endothelin-1 (ET-1) and tumor necrosis factor-α (TNF-α). The high-salt diet causes disorders in bile acid metabolism. The levels of four differential bile acids (glycocholic acid, taurolithocholic acid, tauroursodeoxycholic acid, and glycolithocholic acid) significantly increased in the high-salt group. Further correlation analysis indicated that the levels of ET-1 and TNF-α were positively correlated with these differential bile acid levels. This study provides new evidence for salt-sensitive cardiovascular diseases and metabolic changes caused by a high-salt diet in rats.

Differential changes in end organ immune cells and inflammation in salt-sensitive hypertension: effects of increasing M2 macrophages

Salt-sensitive hypertension (SSHTN) is associated with M1 macrophage polarization and inflammatory responses, leading to inflammation-associated lymphangiogenesis and functional impairment across multiple organs, including kidneys and gonads. However, it remains unclear whether promoting M2 macrophage polarization can alleviate the hypertension, inflammation, and end organ damage in mice with salt sensitive hypertension (SSHTN). Male and female mice were made hypertensive by administering nitro-L-arginine methyl ester hydrochloride (L-NAME; 0.5 mg/ml) for 2 weeks in the drinking water, followed by a 2-week interval without any treatments, and a subsequent high salt diet for 3 weeks (SSHTN). AVE0991 (AVE) was intraperitoneally administered concurrently with the high salt diet. Control mice were provided standard diet and tap water. AVE treatment significantly attenuated BP and inflammation in mice with SSHTN. Notably, AVE promoted M2 macrophage polarization, decreased pro-inflammatory immune cell populations, and improved function in renal and gonadal tissues of mice with SSHTN. Additionally, AVE decreased lymphangiogenesis in the kidneys and testes of male SSHTN mice and the ovaries of female SSHTN mice. These findings highlight the effectiveness of AVE in mitigating SSHTN-induced elevated BP, inflammation, and end organ damage by promoting M2 macrophage polarization and suppressing pro-inflammatory immune responses. Targeting macrophage polarization emerges as a promising therapeutic approach for alleviating inflammation and organ damage in SSHTN. Further studies are warranted to elucidate the precise mechanisms underlying AVE-mediated effects and to assess its clinical potential in managing SSHTN.

High salt intake and HIV infection on endothelial glycocalyx shedding in salt-sensitive hypertension

The endothelial glycocalyx is closely associated with various physiological and pathophysiological events. Significant modification of the endothelial glycocalyx is an early process in the pathogenesis of cardiovascular disease. High dietary salt and HIV infection damages the endothelial glycocalyx causing endothelial dysfunction and increasing the risk for salt-sensitive hypertension and cardiovascular disease. The two factors, HIV infection and dietary salt are critical independent predictors of hypertension and cardiovascular disease and often synergize to exacerbate and accelerate disease pathogenesis. Salt-sensitive hypertension is more common among people living with HIV and is associated with risk for cardiovascular disease, stroke, heart attack and even death. However, the underlying mechanisms linking endothelial glycocalyx damage to dietary salt and HIV infection are lacking. Yet, both HIV infection/treatment and dietary salt are closely linked to endothelial glycocalyx damage and development of salt-sensitive hypertension. Moreover, the majority of individuals globally, consume more salt than is recommended and the burden of HIV especially in sub-Sahara Africa is disproportionately high. In this review, we have discussed the missing link between high salt and endothelial glycocalyx shedding in the pathogenesis of salt-sensitive hypertension. We have further elaborated the role played by HIV infection and treatment in modifying endothelial glycocalyx integrity to contribute to the development of hypertension and cardiovascular disease.

Intermuscular adipose tissue accumulation is associated with higher tissue sodium in healthy individuals

BACKGROUND AND AIMS

High tissue sodium accumulation and intermuscular adipose tissue (IMAT) are associated with aging, type 2 diabetes, and chronic kidney disease. In this study, we aim to investigate whether high lower-extremity tissue sodium accumulation relates to IMAT quantity and whether systemic inflammatory mediators and adipocytokines contribute to such association.

METHODS

Tissue sodium content and IMAT accumulation (percentage of IMAT area to muscle area) were measured in 83 healthy individuals using sodium imaging (23Na-MRI) and proton (1H-MRI) imaging of the calf. Insulin sensitivity was assessed by glucose disposal rate (GDR) measured with the hyperinsulinemic-euglycemic clamp.

RESULTS

Median (interquartile range) muscle and skin sodium contents were 16.6 (14.9, 19.0) and 12.6 (10.9, 16.7) mmol/L, respectively. Median IMAT was 3.69 (2.80, 5.37) %. In models adjusted for age, sex, BMI, GDR, adiponectin, and high-sensitivity C-reactive protein, increasing tissue sodium content was significantly associated with higher IMAT quantity (p = 0.018 and 0.032 for muscle and skin tissue sodium, respectively). In subgroup analysis stratified by sex, skin sodium was significantly associated with IMAT only among men. In interaction analysis, the association between skin sodium and IMAT was greater with increasing levels of high-sensitivity C-reactive protein and interleukin-6 (p for interaction = 0.022 and 0.006, respectively).

CONCLUSIONS

Leg muscle and skin sodium are associated with IMAT quantity among healthy individuals. The relationship between skin sodium and IMAT may be mediated by systemic inflammation.

Hypotensive drugs mitigate the high-sodium diet-induced pro-inflammatory activation of mouse macrophages in vivo

Nowadays, there is an increasing emphasis on the need to alleviate the chronic inflammatory response to effectively treat hypertension. However, there are still gaps in our understanding on how to achieve this. Therefore, research on interaction of antihypertensive drugs with the immune system is extremely interesting, since their therapeutic effect could partly result from amelioration of hypertension-related inflammation, in which macrophages seem to play a pivotal role. Thus, current comprehensive studies have investigated the impact of repeatedly administered hypotensive drugs (captopril, olmesartan, propranolol, carvedilol, amlodipine, verapamil) on macrophage functions in the innate and adaptive immunity, as well as if drug-induced effects are affected by a high-sodium diet (HSD), one of the key environmental risk factors of hypertension. Although the assayed medications increased the generation of reactive oxygen and nitrogen intermediates by macrophages from standard fed donors, they reversed HSD-induced enhancing effects on macrophage oxidative burst and secretion of pro-inflammatory cytokines. On the other hand, some drugs increased macrophage phagocytic activity and the expression of surface markers involved in antigen presentation, which translated into enhanced macrophage ability to activate B cells for antibody production. Moreover, the assayed medications augmented macrophage function and the effector phase of contact hypersensitivity reaction, but suppressed the sensitization phase of cell-mediated hypersensitivity under HSD conditions. Our current findings contribute to the recognition of mechanisms, by which excessive sodium intake affects macrophage immune activity in hypertensive individuals, and provide evidence that the assayed medications mitigate most of the HSD-induced adverse effects, suggesting their additional protective therapeutic activity.

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.

Effects of NLRP3 Inflammasome Mediated Pyroptosis on Cardiovascular Diseases and Intervention Mechanism of Chinese Medicine

Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome signaling pathway is an important mechanism underlying myocardial pyroptosis and plays an important role in inflammatory damage to myocardial tissue in patients with cardiovascular diseases (CVDs), such as diabetic cardiomyopathy, ischemia/reperfusion injury, myocardial infarction, heart failure and hypertension. Noncoding RNAs (ncRNAs) are important regulatory factors. Many Chinese medicine (CM) compounds, including their effective components, can regulate pyroptosis and exert myocardium-protecting effects. The mechanisms underlying this protection include inhibition of inflammasome protein expression, Toll-like receptor 4-NF-κB signal pathway activation, oxidative stress, endoplasmic reticulum stress (ERS), and mixed lineage kinase 3 expression and the regulation of silent information regulator 1. The NLRP3 protein is an important regulatory target for CVD prevention and treatment with CM. Exploring the effects of the interventions mediated by CM and the related mechanisms provides new ideas and perspectives for CVD prevention and treatment.

Association between systemic immunity-inflammation index and hypertension in US adults from NHANES 1999-2018

Hypertension is a disease closely related to inflammation, and the systemic immunity-inflammation index (SII) is a new and easily detectable inflammatory marker. We aimed to investigate the association between SII and hypertension risk in a adult population in the US. We utilized data from the National Health and Nutrition Examination Survey spanning from 1999 to 2018, incorporating comprehensive information from adults reporting hypertension. This included details on blood pressure monitoring, complete blood cell counts, and standard biochemical results. The SII was computed as the platelet count multiplied by the neutrophil count divided by the lymphocyte count. We employed a weighted multivariate logistic regression model to examine the correlation between SII and hypertension. Subgroup analyses were conducted to explore potential influencing factors. Furthermore, smooth curve fitting and two-piecewise logistic regression analysis were employed to describe non-linear relationships and identify inflection points. This population-based study involved 44,070 adults aged 20-85 years. Following Ln-transformation of the SII, multivariable logistic regression revealed that, in a fully adjusted model, participants in the highest quartile of Ln(SII) had a 12% increased risk of hypertension compared to those in the lowest quartile, which was statistically significant (OR:1.12; 95% CI 1.01, 1.24; P < 0.001), with a P for trend = 0.019. Subgroup analysis indicated no significant interactions between Ln(SII) and specific subgroups except for the body mass index subgroup (all P for interaction > 0.05). Additionally, the association between Ln(SII) and hypertension displayed a U-shaped curve, with an inflection point at 5.89 (1000 cells/μl). Based on this research result, we found a U-shaped correlation between elevated SII levels and hypertension risk in American adults, with a inflection point of 5.89 (1000 cells)/μl). To validate these findings, larger scale prospective surveys are needed to support the results of this study and investigate potential mechanisms.

Eicosanoid-Regulated Myeloid ENaC and Isolevuglandin Formation in Human Salt-Sensitive Hypertension

BACKGROUND

The mechanisms by which salt increases blood pressure in people with salt sensitivity remain unclear. Our previous studies found that high sodium enters antigen-presenting cells (APCs) via the epithelial sodium channel and leads to the production of isolevuglandins and hypertension. In the current mechanistic clinical study, we hypothesized that epithelial sodium channel-dependent isolevuglandin-adduct formation in APCs is regulated by epoxyeicosatrienoic acids (EETs) and leads to salt-sensitive hypertension in humans.

METHODS

Salt sensitivity was assessed in 19 hypertensive subjects using an inpatient salt loading and depletion protocol. Isolevuglandin-adduct accumulation in APCs was analyzed using flow cytometry. Gene expression in APCs was analyzed using cellular indexing of transcriptomes and epitopes by sequencing analysis of blood mononuclear cells. Plasma and urine EETs were measured using liquid chromatography-mass spectrometry.

RESULTS

Baseline isolevuglandin+ APCs correlated with higher salt-sensitivity index. Isolevuglandin+ APCs significantly decreased from salt loading to depletion with an increasing salt-sensitivity index. We observed that human APCs express the epithelial sodium channel δ subunit, SGK1 (salt-sensing kinase serum/glucocorticoid kinase 1), and cytochrome P450 2S1. We found a direct correlation between baseline urinary 14,15 EET and salt-sensitivity index, whereas changes in urinary 14,15 EET negatively correlated with isolevuglandin+ monocytes from salt loading to depletion. Coincubation with 14,15 EET inhibited high-salt-induced increase in isolevuglandin+ APC.

CONCLUSIONS

Isolevuglandin formation in APCs responds to acute changes in salt intake in salt-sensitive but not salt-resistant people with hypertension, and this may be regulated by renal 14,15 EET. Baseline levels of isolevuglandin+ APCs or urinary 14,15 EET may provide diagnostic tools for salt sensitivity without a protocol of salt loading.

Dendritic cell epithelial sodium channel induced inflammation and salt-sensitive hypertension

PURPOSE OF REVIEW

Salt sensitivity of blood pressure (SSBP) is an independent risk factor for cardiovascular disease. Epithelial sodium channel (ENaC) plays a critical role in renal electrolyte and volume regulation and has been implicated in the pathogenesis of SSBP. This review describes recent advances regarding the role of ENaC-dependent inflammation in the development of SSBP.

RECENT FINDINGS

We recently found that sodium enters dendritic cells via ENaC, a process regulated by serum/glucocorticoid-regulated kinase 1 and epoxyeicosatrienoic acid 14,15. Sodium entry activates NADPH oxidase, leading to the production of isolevuglandins (IsoLGs). IsoLGs adduct self-proteins to form neoantigens in dendritic cells that activate T cells and result in the release of cytokines promoting sodium retention, kidney damage, and endothelial dysfunction in SSBP. Additionally, we described a novel mechanistic pathway involving ENaC and IsoLG-dependent NLRP3 inflammasome activation. These findings hold promise for the development of novel diagnostic biomarkers and therapeutic options for SSBP.

SUMMARY

The exact mechanisms underlying SSBP remain elusive. Recent advances in understanding the extrarenal role of ENaC have opened a new perspective, and further research efforts should focus on understanding the link between ENaC, inflammation, and SSBP.

Poly-(ADP-ribose) polymerases inhibition by olaparib attenuates activities of the NLRP3 inflammasome and of NF-κB in THP-1 monocytes

Poly-(ADP-ribose) polymerases (PARPs) are a protein family that make ADP-ribose modifications on target genes and proteins. PARP family members contribute to the pathogenesis of chronic inflammatory diseases, including atherosclerosis, in which monocytes/macrophages play important roles. PARP inhibition is protective against atherosclerosis. However, the mechanisms by which PARP inhibition exerts this beneficial effect are not well understood. Here we show that in THP-1 monocytes, inhibition of PARP by olaparib attenuated oxidized low-density lipoprotein (oxLDL)-induced protein expressions of nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing-3 (NLRP3) inflammasome components: NLRP3, apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), and caspase-1. Consistent with this effect, olaparib decreased oxLDL-enhanced interleukin (IL)-1β and IL-18 protein expression. Olaparib also decreased the oxLDL-mediated increase in mitochondrial reactive oxygen species. Similar to the effects of the NLRP3 inhibitor, MCC950, olaparib attenuated oxLDL-induced adhesion of monocytes to cultured human umbilical vein endothelial cells and reduced foam cell formation. Furthermore, olaparib attenuated the oxLDL-mediated activation of nuclear factor (NF)-κB through the oxLDL-mediated increase in IκBα phosphorylation and assembly of NF-κB subunits, demonstrated by co-immunoprecipitation of IκBα with RelA/p50 and RelB/p52 subunits. Moreover, PARP inhibition decreased oxLDL-mediated protein expression of a NF-κB target gene, VCAM1, encoding vascular cell adhesion molecule-1. This finding indicates an important role for NF-κB activity in PARP-mediated activation of the NLRP3 inflammasome. Thus, PARP inhibition by olaparib attenuates NF-κB and NLRP3 inflammasome activities, lessening monocyte cell adhesion and macrophage foam cell formation. These inhibitory effects of olaparib on NLRP3 activity potentially protect against atherosclerosis.

Dietary Salt Can Be Crucial for Food-Induced Vascular Inflammation

Salt enhances the taste as well as the nutritional value of food. Besides, several reports are available on the incidence and epidemiology of various illnesses in relation to salt intake. Excessive salt consumption has been found to be linked with high blood pressure, renal disease, and other cardiovascular disorders due to the result of vascular inflammation. Nevertheless, studies aimed at elucidating the molecular processes that produce vascular inflammation have yet to reach their conclusions. This article emphasizes the significance of investigating the mechanisms underlying both acute and chronic vascular inflammation induced by salt. It also explores the logical inferences behind cellular oxidative stress and the role of endothelial dysfunction as the potential initiator of the inflammatory segments that remain poorly understood. It is therefore hypothesized that salt is one of the causes of chronic vascular inflammation such as atherosclerosis. The hypothesis's secrets, when revealed, can help assure cardiovascular health by proactive efforts and the development of appropriate preventative measures, in combination with medication, dietary and lifestyle adjustments.

Anthocyanin attenuates high salt-induced hypertension via inhibiting the hyperactivity of the sympathetic nervous system

BACKGROUND

Anthocyanin plays a protective role in cardiovascular disease through antioxidant effect. Whether anthocyanin can reduce salt-induced hypertension and the related mechanisms remain unclear.

METHODS

Chronic infusion of vehicle (artificial cerebrospinal fluid, aCSF, 0.4 μL/h) or anthocyanin (10 mg/kg, 0.4 μL/h) into bilateral paraventricular nucleus (PVN) of Sprague-Dawley rats was performed. Then, the rats were fed a high salt diet (8% NaCl, HS) or normal salt diet (0.9%, NaCl, NS) for 4 weeks.

RESULTS

High salt diet induced an increase in blood pressure and peripheral sympathetic nerve activity (increased LF/HF and decreased SDNN and RMSSD), which was accompanied by increased reactive oxygen species (ROS) production and angiotensin II type-1 receptor (AT₁R) expression and function in the PVN. Moreover, the NOD-like receptor protein 3 (NLRP3) and related inflammatory proteins (caspase-1) expression, the pro-inflammatory cytokine levels including IL-1β and TNF-α were higher in PVN of rats with a high salt diet. Bilateral PVN infusion of anthocyanin attenuated NLRP3-dependent inflammation (NLRP3, caspase-1, IL-1β and TNF-α) and ROS production, reduced AT₁R expression and function in PVN and lowered peripheral sympathetic nerve activity and blood pressure in rats with salt-induced hypertension.

CONCLUSIONS

Excessive salt intake activates NLRP3-dependent inflammation and oxidative stress and increased AT₁R expression and function in the PVN. Bilateral PVN infusion of anthocyanin lowers peripheral sympathetic nerve activity and blood pressure in rats with salt-induced hypertension by improvement of expression and function of AT₁R in the PVN through inhibiting NLRP3 related inflammatory and oxidative stress.

Targeting the NLRP3 inflammasome for the treatment of hypertensive target organ damage: Role of natural products and formulations

BACKGROUND AND AIM

Hypertension is a major global health problem that causes target organ damage (TOD) in the heart, brain, kidney, and blood vessels. The mechanisms of hypertensive TOD are not fully understood, and its treatment is challenging. This review provides an overview of the current knowledge on the role of Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome in hypertensive TOD and the natural products and formulations that inhibit it.

METHODS

We searched PubMed, Web of Science, Google Scholar, and CNKI for relevant articles using the keywords "hypertension," "target organ damage," "NLRP3 inflammasome," "natural products," and "formulations." We reviewed the effects of the NLRP3 inflammasome on hypertensive TOD in different organs and discussed the natural products and formulations that modulate it.

KEY RESULTS

In hypertensive TOD, the NLRP3 inflammasome is activated by various stimuli such as oxidative stress and inflammation. Activation of NLRP3 inflammasome leads to the production of pro-inflammatory cytokines that exacerbate tissue damage and dysfunction. Natural products and formulations, including curcumin, resveratrol, triptolide, and allicin, have shown protective effects against hypertensive TOD by inhibiting the NLRP3 inflammasome.

CONCLUSIONS AND IMPLICATIONS

The NLRP3 inflammasome is a promising therapeutic target in hypertensive TOD. Natural products and formulations that inhibit the NLRP3 inflammasome may provide novel drug candidates or therapies for hypertensive TOD. Further studies are needed to elucidate the molecular mechanisms and optimize the dosages of these natural products and formulations and evaluate their clinical efficacy and safety.

Gut microbiota and hypertension: a bibliometric analysis of recent research (2014-2023)

Background

Cardiovascular diseases persist as the primary cause of mortality in the global population. Hypertension (HTN) is widely recognized as one of the most crucial risk factors contributing to severe cardiovascular conditions. In recent years, a growing body of research has highlighted the therapeutic potential of gut microbiota (GM) in addressing cardiovascular diseases, particularly HTN. Consequently, unraveling and synthesizing the connections between GM and HTN, key research domains, and the underlying interaction mechanisms have grown increasingly vital.

Methods

We retrieved articles related to GM and HTN from 2014 to 2023 using Web of Science. Bibliometric tools employed in this analysis include CiteSpace and VOSviewer.

Result

From 2014 to 2023, we identified 1,730 related articles. These articles involved 88 countries (regions) and 9,573 authors. The articles were published in 593 journals, with 1000 references exhibiting co-occurrence more than 10 times. The number of studies in this field has been increasing, indicating that it remains a research hotspot. We expect this field to continue gaining attention in the future. China leads in the number of published articles, while the United States boasts the most extensive international collaborations, signifying its continued prominence as a research hub in this domain. Tain You-Lin, Hsu Chien-Ning, Raizada Mohan K, and Yang Tao are among the authors with the highest publication volume. Publications in this field are frequently found in nutrition, cardiovascular, and molecular biology journals. The most frequently occurring keywords include metabolic syndrome, cardiovascular disease, inflammation, short-chain fatty acids, trimethylamine N-oxide, chronic kidney disease, heart failure, and high-salt diet.

Conclusion

The relationship between GM and HTN is presently one of the most active research areas. By employing bibliometric tools, we analyzed critical and innovative articles in this field to provide an objective summary of the primary research directions, such as the relationship between GM and HTN, GM metabolites, high-salt diet, the developmental origins of health and disease, obstructive sleep apnea-Induced hypertension and antihypertensive peptide. Our analysis aims to offer researchers insights into hotspots and emerging trends in the field of GM and HTN for future research reference.

Glycocalyx-Sodium Interaction in Vascular Endothelium

The glycocalyx generally covers almost all cellular surfaces, where it participates in mediating cell-surface interactions with the extracellular matrix as well as with intracellular signaling molecules. The endothelial glycocalyx that covers the luminal surface mediates the interactions of endothelial cells with materials flowing in the circulating blood, including blood cells. Cardiovascular diseases (CVD) remain a major cause of morbidity and mortality around the world. The cardiovascular risk factors start by causing endothelial cell dysfunction associated with destruction or irregular maintenance of the glycocalyx, which may culminate into a full-blown cardiovascular disease. The endothelial glycocalyx plays a crucial role in shielding the cell from excessive exposure and absorption of excessive salt, which can potentially cause damage to the endothelial cells and underlying tissues of the blood vessels. So, in this mini review/commentary, we delineate and provide a concise summary of the various components of the glycocalyx, their interaction with salt, and subsequent involvement in the cardiovascular disease process. We also highlight the major components of the glycocalyx that could be used as disease biomarkers or as drug targets in the management of cardiovascular diseases.

Pathogenesis of Hypertension in Metabolic Syndrome: The Role of Fructose and Salt

Metabolic syndrome is manifested by visceral obesity, hypertension, glucose intolerance, hyperinsulinism, and dyslipidemia. According to the CDC, metabolic syndrome in the US has increased drastically since the 1960s leading to chronic diseases and rising healthcare costs. Hypertension is a key component of metabolic syndrome and is associated with an increase in morbidity and mortality due to stroke, cardiovascular ailments, and kidney disease. The pathogenesis of hypertension in metabolic syndrome, however, remains poorly understood. Metabolic syndrome results primarily from increased caloric intake and decreased physical activity. Epidemiologic studies show that an enhanced consumption of sugars, in the form of fructose and sucrose, correlates with the amplified prevalence of metabolic syndrome. Diets with a high fat content, in conjunction with elevated fructose and salt intake, accelerate the development of metabolic syndrome. This review article discusses the latest literature in the pathogenesis of hypertension in metabolic syndrome, with a specific emphasis on the role of fructose and its stimulatory effect on salt absorption in the small intestine and kidney tubules.