Toll-like receptor 4 contributes to vascular remodelling and endothelial dysfunction in angiotensin II-induced hypertension

Toll-like receptor 4 mutation mitigates gut microbiota-mediated hypertensive kidney injury

Hypertension-associated dysbiosis is linked to several clinical complications, including inflammation and possible kidney dysfunction. Inflammation and TLR4 activation during hypertension result from gut dysbiosis-related impairment of intestinal integrity. However, the contribution of TLR4 in kidney dysfunction during hypertension-induced gut dysbiosis is unclear. We designed this study to address this knowledge gap by utilizing TLR4 normal (TLR4N) and TLR4 mutant (TLR4M) mice. These mice were infused with high doses of Angiotensin-II for four weeks to induce hypertension. Results suggest that Ang-II significantly increased renal arterial resistive index (RI), decreased renal vascularity, and renal function (GFR) in TLR4N mice compared to TLR4M. 16 S rRNA sequencing analysis of gut microbiome revealed that Ang-II-induced hypertension resulted in alteration of Firmicutes: Bacteroidetes ratio in the gut of both TLR4N and TLR4M mice; however, it was not comparably rather differentially. Additionally, Ang-II-hypertension decreased the expression of tight junction proteins and increased gut permeability, which were more prominent in TLR4N mice than in TLR4M mice. Concomitant with gut hyperpermeability, an increased bacterial component translocation to the kidney was observed in TLR4N mice treated with Ang-II compared to TLR4N plus saline. Interestingly, microbiota translocation was mitigated in Ang-II-hypertensive TLR4M mice. Furthermore, Ang-II altered the expression of inflammatory (IL-1β, IL-6) and anti-inflammatory IL-10) markers, and extracellular matrix proteins, including MMP-2, -9, -14, and TIMP-2 in the kidney of TLR4N mice, which were blunted in TLR4M mice. Our data demonstrate that ablation of TLR4 attenuates hypertension-induced gut dysbiosis resulting in preventing gut hyperpermeability, bacterial translocation, mitigation of renal inflammation and alleviation of kidney dysfunction.

Mechanisms of Vascular Inflammation and Potential Therapeutic Targets: A Position Paper From the ESH Working Group on Small Arteries

Inflammatory responses in small vessels play an important role in the development of cardiovascular diseases, including hypertension, stroke, and small vessel disease. This involves various complex molecular processes including oxidative stress, inflammasome activation, immune-mediated responses, and protein misfolding, which together contribute to microvascular damage. In addition, epigenetic factors, including DNA methylation, histone modifications, and microRNAs influence vascular inflammation and injury. These phenomena may be acquired during the aging process or due to environmental factors. Activation of proinflammatory signaling pathways and molecular events induce low-grade and chronic inflammation with consequent cardiovascular damage. Identifying mechanism-specific targets might provide opportunities in the development of novel therapeutic approaches. Monoclonal antibodies targeting inflammatory cytokines and epigenetic drugs, show promise in reducing microvascular inflammation and associated cardiovascular diseases. In this article, we provide a comprehensive discussion of the complex mechanisms underlying microvascular inflammation and offer insights into innovative therapeutic strategies that may ameliorate vascular injury in cardiovascular disease.

Unraveling the Impact of Extracellular Vesicle-Depleted Serum on Endothelial Cell Characteristics over Time

Extracellular vesicles (EVs) are produced by all kinds of cells, including endothelial cells. It has been observed that EVs present in fetal bovine serum (FBS), broadly used in cell culture, can be a confounding factor and lead to misinterpretation of results. To investigate this phenomenon, human brain microvascular endothelial cells (HBMECs) were cultured for 2 or 24 h in the presence of EV-depleted FBS (EVdS). Cell death, gene and protein expression, and the presence of EVs isolated from these cells were evaluated. The uptake of EVs, intercellular adhesion molecule 1 (ICAM-1) expression, and monocyte adhesion to endothelial cells exposed to EVs were also evaluated. Our results revealed higher apoptosis rates in cells cultured with EVdS for 2 and 24 h. There was an increase in interleukin 8 (IL8) expression after 2 h and a decrease in interleukin 6 (IL6) and IL8 expression after 24 h of culture. Among the proteins identified in EVs isolated from cells cultured for 2 h (EV2h), several were related to ribosomes and carbon metabolism. EVs from cells cultured for 24 h (EV24h) presented a protein profile associated with cell adhesion and platelet activation. Additionally, HBMECs exhibited increased uptake of EV2h. Treatment of endothelial cells with EV2h resulted in greater ICAM-1 expression and greater adherence to monocytes than did treatment with EV24h. According to our data, HBMEC cultivated with EVdS produce EVs with different physical characteristics and protein levels that vary over time.

Advances in Research Related to MicroRNA for Diabetic Retinopathy

Diabetic retinopathy (DR) is a severe microvascular complication of diabetes and is one of the primary causes of blindness in the working-age population in Europe and the United States. At present, no cure is available for DR, but early detection and timely intervention can prevent the rapid progression of the disease. Several treatments for DR are known, primarily ophthalmic treatment based on glycemia, blood pressure, and lipid control, which includes laser photocoagulation, glucocorticoids, vitrectomy, and antivascular endothelial growth factor (anti-VEGF) medications. Despite the clinical efficacy of the aforementioned therapies, none of them can entirely shorten the clinical course of DR or reverse retinopathy. MicroRNAs (miRNAs) are vital regulators of gene expression and participate in cell growth, differentiation, development, and apoptosis. MicroRNAs have been shown to play a significant role in DR, particularly in the molecular mechanisms of inflammation, oxidative stress, and neurodegeneration. The aim of this review is to systematically summarize the signaling pathways and molecular mechanisms of miRNAs involved in the occurrence and development of DR, mainly from the pathogenesis of oxidative stress, inflammation, and neovascularization. Meanwhile, this article also discusses the research progress and application of miRNA-specific therapies for DR.

The Melatonin Derivative ITH13001 Prevents Hypertension and Cardiovascular Alterations in Angiotensin II-Infused Mice

Inflammatory mechanisms and oxidative stress seem to contribute to the pathogenesis of hypertension. ITH13001 is a melatonin-phenyl-acrylate hybrid that moderately induces the antioxidant transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) and has a potent oxidant scavenging effect compared with other derivatives of its family. Here we investigated the effect of ITH13001 on hypertension and the associated cardiovascular alterations. Angiotensin II (AngII)-infused mice were treated with ITH13001 (1 mg/kg per day, i.p.) for 2 weeks. The ITH13001 treatment prevented: 1) the development of hypertension, cardiac hypertrophy, and increased collagen and B-type natriuretic peptide (Bnp) expression in the heart; 2) the reduction of elasticity, incremental distensibility, fenestrae area, intraluminal diameter, and endothelial cell number in mesenteric resistance arteries (MRA); 3) the endothelial dysfunction in aorta and MRA; 4) the plasma and cardiovascular oxidative stress and the reduced aortic nitric oxide (NO) bioavailability; 5) the increased cardiac levels of the cytokines interleukin (IL)-1β, IL-6, and C-C motif chemokine ligand 2 (Ccl2), the T cell marker cluster of differentiation 3 (Cd3), the inflammasome NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3), the proinflammatory enzymes inducible nitric oxide synthase (iNOS) and COX-2, the toll-like receptor 4 (TLR4) adapter protein myeloid differentiation primary response 88 (MyD88), and the nuclear factor kappa B (NF-κB) subunit p65; 6) the greater aortic expression of the cytokines tumor necrosis factor alpha (Tnf-α), Ccl2 and IL-6, Cd3, iNOS, MyD88, and NLRP3. Although ITH13001 increased nuclear Nrf2 levels and heme oxygenase 1 (HO-1) expression in vascular smooth muscle cells, both cardiac and vascular Nrf2, Ho-1, and NADPH quinone dehydrogenase 1 (Nqo1) levels remained unmodified irrespective of AngII infusion. Summarizing, ITH13001 improved hypertension-associated cardiovascular alterations independently of Nrf2 pathway activation, likely due to its direct antioxidant and anti-inflammatory properties. Therefore, ITH13001 could be a useful therapeutic strategy in patients with resistant hypertension. SIGNIFICANCE STATEMENT: Despite the existing therapeutic arsenal, only half of the patients treated for hypertension have adequately controlled blood pressure; therefore, the search for new compounds to control this pathology and the associated damage to end-target organs (cerebral, cardiac, vascular, renal) is of particular interest. The present study demonstrates that a new melatonin derivative, ITH13001, prevents hypertension development and the associated cardiovascular alterations due to its antioxidant and anti-inflammatory properties, making this compound a potential candidate for treatment of resistant hypertensive patients.

Angiotensin II-induced vascular endothelial cells ferroptosis via P53-ALOX12 signal axis

OBJECTIVES

The present study aimed to investigate the effect and mechanism of angiotensin II-induced ferroptosis in vascular endothelial cells.

METHODS

In vitro, HUVECs were treated with AngII, AT_1/2 R antagonist, P53 inhibitor, or their combinations. MDA and intracellular iron content were evaluated using an ELISA assay. The expression of ALOX12, P53, P21, and SLC7A11 were determined by western blotting in HUVECs and then confirmed through RT-PCR.

RESULTS

As the concentration of Ang II (0, 0.1,1,10,100, and 1000uM for 48 h) increased, the level of MDA and intracellular iron content increased in HUVECs. Compared with the single AngII group, ALOX12, p53, MDA, and intracellular iron content in AT_1/2R antagonist group decreased significantly. In pifithrin-α hydrobromide-treated, ALOX12, P21,MDA, and intracellular iron content decreased significantly as compared to the single AngII group. Similarly, the effect of combined use of blockers is stronger than that of blockers alone.

CONCLUSIONS

AngII can induce ferroptosis of vascular endothelial cells. The mechanism of AngII-induced ferroptosis may be regulated through the signal axis of p53-ALOX12.

Targeting MyD88: Therapeutic mechanisms and potential applications of the specific inhibitor ST2825

BACKGROUND

Myeloid differentiation factor-88 (MyD88) is a crucial adapter protein that coordinates the innate immune response and establishes an adaptive immune response. The interaction of the Toll/Interleukin-1 receptor (IL-1R) superfamily with MyD88 triggers the activation of various signalling pathways such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), promoting the production of a variety of immune and inflammatory mediators and potentially driving the development of a variety of diseases.

OBJECTIVE

This article will explore the therapeutic potential and mechanism of the MyD88-specific inhibitor ST2825 and describe its use in the treatment of several diseases. We envision future research and clinical applications of ST2825 to provide new ideas for the development of anti-inflammatory drugs and disease-specific drugs to open new horizons for the prevention and treatment of related inflammatory diseases.

MATERIALS AND METHODS

This review analysed relevant literature in PubMed and other databases. All relevant studies on MyD88 inhibitors and ST2825 that were published in the last 20 years were used as screening criteria. These studies looked at the development and improvement of MyD88 inhibitors and ST2825.

RESULTS

Recent evidence using the small-molecule inhibitor of ST2825 has suggested that blocking MyD88 activity can be used to treat diseases such as neuroinflammation, inflammatory diseases such as acute liver/kidney injury, or autoimmune diseases such as systemic lupus erythematosus and can affect transplantation immunity. In addition, ST2825 has potential therapeutic value in B-cell lymphoma with the MyD88 L265P mutation.

CONCLUSION

Targeting MyD88 is a novel therapeutic strategy, and scientific research is presently focused on the development of MyD88 inhibitors. The peptidomimetic compound ST2825 is a widely studied small-molecule inhibitor of MyD88. Thus, ST2825 may be a potential therapeutic small-molecule agent for modulating host immune regulation in inflammatory diseases and inflammatory therapy.

Source apportionment of heavy metals in PM2.5 samples and effects of heavy metals on hypertension among schoolchildren in Tianjin

The prevalence of hypertension in children has increased significantly in recent years in China. The aim of this study was to provide scientific support to control ambient heavy metals (HMs) pollution and prevent childhood hypertension. In this study, ambient HMs in PM2.5 were collected, and 1339 students from Tianjin were randomly selected. Positive matrix factorization (PMF) was used to identify and determine the sources of HMs pollution. The generalized linear model, Bayesian kernel machine regression (BKMR) and the quantile g-computation method were used to analyze the relationships between exposure to HMs and the risk of childhood hypertension. The results showed that HMs in PM2.5 mainly came from four sources: soil dust, coal combustion, incineration of municipal waste and the metallurgical industry. The positive relationships between As, Se and Pb exposures and childhood hypertension risk were found. Coal combustion and incineration of municipal waste were important sources of HMs in the occurrence of childhood hypertension. Based on these accomplishments, this study could provide guidelines for the government and individuals to alleviate the damaging effects of HMs in PM2.5. The government must implement policies to control prime sources of HMs pollution.

PROGRESSION OF VASCULAR FUNCTION AND BLOOD PRESSURE IN A MOUSE MODEL OF KAWASAKI DISEASE

ABSTRACT

Kawasaki disease (KD) is a systemic vasculitis of childhood characterized by vascular damage in the acute stage, which can persist into the late stage. The vascular mechanisms in the cardiovascular risk of KD are not fully studied. We investigated the vascular function and blood pressure in a murine model of KD. We used the Candida albicans water-soluble (CAWS) fraction model. Mice were injected with 4 mg CAWS for 5 consecutive days and separated into three groups. Control, CAWS 7 days (C7), and CAWS 28 days (C28). Hearts and arteries were harvested for vascular characterization. Rat aortic smooth muscle cells were used to studies in vitro. C7 presented elevated inflammatory markers in the coronary area and abdominal aortas, whereas C28 showed severe vasculitis. No difference was found in blood pressure parameters. Vascular dysfunction characterized by higher contractility to norepinephrine in C7 and C28 in aortic rings was abolished by blocking nitric oxide (NO), reactive oxygen species, and cyclooxygenase (COX)-derived products. The CAWS complex increased COX2 expression in rat aortic smooth muscle cells, which was prevented by Toll-like receptor 4 antagonist. Our data indicate that the murine model of KD is associated with vascular dysfunction likely dependent on COX-derived products, oxidant properties, and NO bioavailability. Furthermore, vascular smooth muscle cell may present an important role in the genesis of vascular dysfunction and vasculitis via the Toll-like receptor 4 pathway. Finally, the CAWS model seems not to be appropriate to study KD-associated shock. More studies are necessary to understand whether vascular dysfunction and COXs are triggers for vasculitis.

Regulation by Nrf2 of IL-1β-induced inflammatory and oxidative response in VSMC and its relationship with TLR4

Introduction: Vascular oxidative stress and inflammation play an important role in the pathogenesis of cardiovascular diseases (CVDs). The proinflammatory cytokine Interleukin-1β (IL-1β) participates in the vascular inflammatory and oxidative responses and influences vascular smooth muscle cells (VSMC) phenotype and function, as well as vascular remodelling in cardiovascular diseases. The Toll-like receptor 4 (TLR4) is also involved in the inflammatory response in cardiovascular diseases. A relationship between Interleukin-1β and Toll-like receptor 4 pathway has been described, although the exact mechanism of this interaction remains still unknown. Moreover, the oxidative stress sensitive transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) promotes the transcription of several antioxidant and anti-inflammatory genes. Nuclear factor-erythroid 2-related factor 2 activators have shown to possess beneficial effects in cardiovascular diseases in which oxidative stress and inflammation are involved, such as hypertension and atherosclerosis; however, the molecular mechanisms are not fully understood. Here, we analysed the role of Toll-like receptor 4 in the oxidative and inflammatory effects of Interleukin-1β as well as whether nuclear factor-erythroid 2-related factor 2 activation contributes to vascular alterations by modulating these effects. Materials: For this purpose, vascular smooth muscle cells and mice aortic segments stimulated with Interleukin-1β were used. Results: Interleukin-1β induces MyD88 expression while the Toll-like receptor 4 inhibitor CLI-095 reduces the Interleukin-1β-elicited COX-2 protein expression, reactive oxygen species (ROS) production, vascular smooth muscle cells migration and endothelial dysfunction. Additionally, Interleukin-1β increases nuclear factor-erythroid 2-related factor 2 nuclear translocation and expression of its downstream proteins heme oxygenase-1, NAD(P)H:quinone oxidoreductase 1 and superoxide dismutase-2, by an oxidative stress-dependent mechanism; moreover, Interleukin-1β reduces the expression of the nuclear factor-erythroid 2-related factor 2 inhibitor Keap1. The nuclear factor-erythroid 2-related factor 2 activator tert-butylhydroquinone (tBHQ) reduces the effects of Interleukin-1β on the increased reactive oxygen species production and the expression of the proinflammatory markers (p-p38, p-JNK, p-c-Jun, COX-2), the increased cell proliferation and migration and prevents the Interleukin-1β-induced endothelial dysfunction in mice aortas. Additionally, tert-butylhydroquinone also reduces the increased MyD88 expression, NADPHoxidase activity and cell migration induced by lipopolysaccharide. Conclusions: In summary, this study reveals that Toll-like receptor 4 pathway contributes to the prooxidant and proinflammatory Interleukin-1β-induced effects. Moreover, activation of nuclear factor-erythroid 2-related factor 2 prevents the deleterious effects of Interleukin-1β, likely by reducing Toll-like receptor 4-dependent pathway. Although further research is needed, the results are promising as they suggest that nuclear factor-erythroid 2-related factor 2 activators might protect against the oxidative stress and inflammation characteristic of cardiovascular diseases.

Synergistic effect of arginine and Lactobacillus plantarum against potassium dichromate induced-acute liver and kidney injury in rats: Role of iNOS and TLR4/NF-κB signaling pathways

Objectives

Our study was conducted to evaluate the synergistic effect of arginine (ARG) and Lactobacillus plantarum against potassium dichromate (K2Cr2O7) induced-acute hepatic and kidney injury.

Materials and Methods

Fifty male Wistar rats were divided into five groups. The control group received distilled water. The potassium dichromate group (PDC) received a single dose of PDC (20 mg/kg; SC). The arginine group (ARG) and Lactobacillus plantarum group received either daily doses of ARG (100 mg/kg, PO) or L. plantarum (10⁹ CFU/ml, PO) for 14 days. The combination group (ARG+L. plantarum) received daily doses of ARG (100 mg/kg) with L. plantarum (10⁹ CFU/ml), orally for 14 days, before induction of acute liver and kidney injury. Forty eight hours after the last dose of PDC, serum biochemical indices, oxidative stress biomarkers, pro-inflammatory cytokines, histopathological and immunohistochemical analysis were evaluated.

Results

Combining ARG with L. plantarum restored the levels of serum hepatic & kidney enzymes, hepatic & renal oxidative stress biomarkers, and TLR 4/ NF-κB signaling pathway. Furthermore, they succeeded in decreasing the expression of iNOS and ameliorate the hepatic and renal markers of apoptosis: Caspase-3, Bax, and Bcl2.

Conclusion

This study depicts that combining ARG with L. plantarum exerted a new bacteriotherapy against hepatic and renal injury caused by PDC.

Bioactive compounds modulating Toll-like 4 receptor (TLR4)-mediated inflammation: pathways involved and future perspectives

Chronic inflammation is associated with the development and progression of several noncommunicable diseases, such as diabetes, cardiovascular disease, chronic kidney disease, cancer, and nonalcoholic fatty liver disease. Evidence suggests that pattern recognition receptors that identify pathogen-associated molecular patterns and danger-associated molecular patterns are crucial in chronic inflammation. Among the pattern recognition receptors, Toll-like receptor 4 (TLR4) stimulates several inflammatory pathway agonists, such as nuclear factor-κB, interferon regulator factor 3, and nod-like receptor pyrin domain containing 3 pathways, which consequently trigger the expression of pro-inflammatory biomarkers, increasing the risk of noncommunicable disease development and progression. Studies have focused on the antagonistic potential of bioactive compounds, following the concept of food as a medicine, in which nutritional strategies may mitigate inflammation via TLR4 modulation. Thus, this review discusses preclinical evidence concerning bioactive compounds from fruit, vegetable, spice, and herb extracts (curcumin, resveratrol, catechin, cinnamaldehyde, emodin, ginsenosides, quercetin, allicin, and caffeine) that may regulate the TLR4 pathway and reduce the inflammatory response. Bioactive compounds can inhibit TLR4-mediated inflammation through gut microbiota modulation, improvement of intestinal permeability, inhibition of lipopolysaccharide-TLR4 binding, and decreasing TLR4 expression by modulation of microRNAs and antioxidant pathways. The responses directly mitigated inflammation, especially nuclear factor-κB activation and inflammatory cytokines release. These findings should be considered for further clinical studies on inflammation-mediated diseases.

7-Hydroxycoumarin Induces Vasorelaxation in Animals with Essential Hypertension: Focus on Potassium Channels and Intracellular Ca2+ Mobilization

Cardiovascular diseases (CVD) are the deadliest noncommunicable disease worldwide. Hypertension is the most prevalent risk factor for the development of CVD. Although there is a wide range of antihypertensive drugs, there still remains a lack of blood pressure control options for hypertensive patients. Additionally, natural products remain crucial to the design of new drugs. The natural product 7-hydroxycoumarin (7-HC) exhibits pharmacological properties linked to antihypertensive mechanisms of action. This study aimed to evaluate the vascular effects of 7-HC in an experimental model of essential hypertension. The isometric tension measurements assessed the relaxant effect induced by 7-HC (0.001 μM–300 μM) in superior mesenteric arteries isolated from hypertensive rats (SHR, 200–300 g). Our results suggest that the relaxant effect induced by 7-HC rely on K⁺-channels (K_ATP, BK_Ca, and, to a lesser extent, K_v) activation and also on Ca²⁺ influx from sarcolemma and sarcoplasmic reticulum mobilization (inositol 1,4,5-triphosphate (IP3) and ryanodine receptors). Moreover, 7-HC diminishes the mesenteric artery’s responsiveness to α1-adrenergic agonist challenge and improves the actions of the muscarinic agonist and NO donor. The present work demonstrated that the relaxant mechanism of 7-HC in SHR involves endothelium-independent vasorelaxant factors. Additionally, 7-HC reduced vasoconstriction of the sympathetic agonist while improving vascular endothelium-dependent and independent relaxation.

Mechanism analysis of octapeptide from microalgae, Isochrysis zhanjiangensis for suppressing vascular injury and angiogenesis in human umbilical vein endothelial cell

Incorporating microalgae active peptides into functional foods is one of the hottest topics in algae research. Ile-Ile-Ala-Val-Glu-Ala-Gly-Cys (IEC) is a novel octapeptide isolated from the microalgae, Isochrysis Zhanjiangensis that inhibits the vascular injury, angiogenesis and has a protective effect on cardiovascular diseases. In this study, IEC can suppress ROS production and inhibit pro-inflammatory factors through the Nrf2/SOD/HO-1 and NF-κB signaling pathways. Additionally, IEC inhibits angiogenesis by reducing the expression of MMP2 and MMP9 via the PI3K/AKT, NF-κB, and MAPK pathways. Molecular docking also demonstrated that IEC possesses an excellent docking effect with SOD, Bcl-2 and VEGFR-2. In conclusion, this study not only provides a new idea for the prevention of cardiovascular diseases, but also proves the possibility of octapeptide (IEC) in functional food and drugs, and further improves the use value of microalgae (Isochrysis Zhanjiangensis).

The Important Role of TaohongSiwu Decoction in Gut Microbial Modulation in Response to High-Salt Diet-Induced Hypertensive Mice

TaohongSiwu decoction (THSWD), a traditional Chinese recipe, has been widely used to treat hypertension since ancient times. However, the mechanisms of its action are still unclear. Herein, we aimed to explore the gut microbial activity of THSWD in high-salt diet-induced hypertensive mice. Eight percent high-salt (NaCl) diet was used to induce hypertension for 4 weeks in a mouse model. Meanwhile, THSWD was used to intervene in the high-salt diet-induced mice, and the efficacy was evaluated by different parameters. Here, we found that THSWD significantly restored blood pressure compared with the model group. Moreover, THSWD effectively protected endothelial function by significantly upregulating the level of nitric oxide (NO) and downregulating the level of endothelin-1 (ET-1), angiotensin I (AngI), and vascular endothelial growth factor (VEGF) in serum compared with the model group. Notably, THSWD significantly upregulated the relative abundance of Dubosiella and downregulated that of Cyanobium_PCC-6307 and DNF00809 at the genus level compared with the model group. The results of PCA and microbial distance calculation further exhibited that THSWD treatment resulted in significant regulation of the microbial community. Furthermore, compared with the model group, THSWD increased the level of vitamin k2 (VK2) in serum. These findings indicate that THSWD could protect blood pressure and endothelial function by regulating gut microbiota and promoting microbial metabolite VK2. These results show the important role of THSWD in regulating the gut microbiota in response to high-salt diet-induced mice.

Silencing of TLR4 Inhibits Atrial Fibrosis and Susceptibility to Atrial Fibrillation via Downregulation of NLRP3-TGF-β in Spontaneously Hypertensive Rats

Introduction. This study was aimed at exploring whether silencing of TLR4 could inhibit atrial fibrosis and susceptibility to atrial fibrillation (AF) by regulating NLRP3-TGF-β in hypertensive rats. Methods. Spontaneously hypertensive rats (SHRs) were transfected with either a virus containing TLR4-shRNA to downregulate TLR4 or an empty virus (vehicle) at the age of 14 weeks. Fibrosis of left atrium and susceptibility to AF were detected, and expression of NLRP3-TGF-β in left atrial tissue at 22 weeks of age was measured. Primary cardiac fibroblasts were transfected with TLR4-shRNA or scrambled vehicle and stimulated with angiotensin (Ang) II. Proliferation of cardiac fibroblasts and expression of NLRP3-TGF-β were detected. Results. Silencing of TLR4 reduced left atrial fibrosis and susceptibility to AF in SHRs and downregulated expression of NLRP3, TGF-β, and collagen I. In vitro, TLR4 silencing reduced proliferation of cardiac fibroblasts induced by Ang II as well as expression of NLRP3, TGF-β, and collagen I. Conclusion. Silencing of TLR4 can downregulate NLRP3-TGF-β to reduce atrial fibrosis and susceptibility to AF in SHRs.

β‑aminoisobutyric acid ameliorates hypertensive vascular remodeling via activating the AMPK/SIRT1 pathway in VSMCs

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play a fundamental role in the pathogenesis of hypertension-related vascular remodeling. β-aminoisobutyric acid (BAIBA) is a nonprotein β-amino acid with multiple pharmacological actions. Recently, BAIBA has been shown to attenuate salt‑sensitive hypertension, but the role of BAIBA in hypertension-related vascular remodeling has yet to be fully clarified. This study examined the potential roles and underlying mechanisms of BAIBA in VSMC proliferation and migration induced by hypertension. Primary VSMCs were cultured from the aortas of Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Our results showed that BAIBA pretreatment obviously alleviated the phenotypic transformation, proliferation, and migration of SHR-derived VSMCs. Exogenous BAIBA significantly inhibited the release of inflammatory cytokines by diminishing phosphorylation and nuclear translocation of p65 NFκB, retarding IκBα phosphorylation and degradation, as well as erasing STAT3 phosphorylation in VSMCs. Supplementation of BAIBA triggered Nrf2 dissociation from Keap1 and inhibited oxidative stress in VSMCs from SHR. Mechanistically, activation of the AMPK/sirtuin 1 (SIRT1) axis was required for BAIBA to cube hypertension-induced VSMC proliferation, migration, oxidative damage and inflammatory response. Most importantly, exogenous BAIBA alleviated hypertension, ameliorated vascular remodeling and fibrosis, abated vascular oxidative burst and inflammation in SHR, an effect that was abolished by deficiency of AMPKα1 and SIRT1. BAIBA might serve as a novel therapeutic agent to prevent vascular remodeling in the context of hypertension.

New insights into the role and therapeutic potential of HSP70 in diabetes

Emerging evidence indicates that HSP70 represents a key mechanism in the pathophysiology of β-cell dysfunction, insulin resistance, and various diabetic complications, including micro- and macro-vascular alterations, as well as impaired hemostasis. Hyperglycemia, a hallmark of both types of diabetes, increases the circulating levels of HSP70 (eHSP70), but there is still divergence about whether diabetes up- or down-regulates the intracellular fraction of this protein (iHSP70). Here, we consider that iHSP70 levels reduce in diabetic arterial structures and that the vascular system is in direct contact with all other systems in the body suggesting that a systemic response might also be happening for iHSP70, which is characterized by decreased levels of HSP70 in the vasculature. Furthermore, although many pathways have been proposed to explain HSP70's functions in diabetes, and organs/tissues/cells-specific variations occur, the membrane-bound receptor of the innate immune system, Toll-like receptor 4, and its downstream signal transduction pathways appear to be a constant, not only when we explore the actions of eHSP70, but also when we assess the contributions of iHSP70. In this review, we focus on discussing the multiple roles of HSP70 across organs/tissues/cells affected by hyperglycemia to further explore the possibility of targeting this protein with pharmacological and non-pharmacological approaches in the context of diabetes.

An insight into the mechanisms of COVID-19, SARS-CoV2 infection severity concerning β-cell survival and cardiovascular conditions in diabetic patients

A significantly high percentage of hospitalized COVID-19 patients with diabetes mellitus (DM) had severe conditions and were admitted to ICU. In this review, we have delineated the plausible molecular mechanisms that could explain why there are increased clinical complications in patients with DM that become critically ill when infected with SARS-CoV2. RNA viruses have been classically implicated in manifestation of new onset diabetes. SARS-CoV2 infection through cytokine storm leads to elevated levels of pro-inflammatory cytokines creating an imbalance in the functioning of T helper cells affecting multiple organs. Inflammation and Th1/Th2 cell imbalance along with Th17 have been associated with DM, which can exacerbate SARS-CoV2 infection severity. ACE-2-Ang-(1-7)-Mas axis positively modulates β-cell and cardiac tissue function and survival. However, ACE-2 receptors dock SARS-CoV2, which internalize and deplete ACE-2 and activate Renin-angiotensin system (RAS) pathway. This induces inflammation promoting insulin resistance that has positive effect on RAS pathway, causes β-cell dysfunction, promotes inflammation and increases the risk of cardiovascular complications. Further, hyperglycemic state could upregulate ACE-2 receptors for viral infection thereby increasing the severity of the diabetic condition. SARS-CoV2 infection in diabetic patients with heart conditions are linked to worse outcomes. SARS-CoV2 can directly affect cardiac tissue or inflammatory response during diabetic condition and worsen the underlying heart conditions.

Sex Differences in TLR4 Expression in SHR Do Not Contribute to Sex Differences in Blood Pressure or the Renal T cell Profile

Hypertension is a primary risk factor for the development of cardiovascular disease. Mechanisms controlling blood pressure (BP) in men and women are still being investigated, however, there is increasing evidence supporting a role for the innate immune system. Specifically, Toll-like receptors (TLR), and TLR4 in particular, have been implicated in the development of hypertension in male spontaneously hypertensive rats (SHR). Despite established sex differences in BP control and inflammatory markers in hypertensive males and females, little is known regarding the role of TLR4 in hypertension in females. Our hypotheses were that male SHR have greater TLR4 expression compared to females, and that sex differences in TLR4 contribute to sex differences in BP and the T cell profile. To test these hypotheses, initial studies measured renal TLR4 protein expression in 13-week old male and female SHR. Additional SHR were implanted with telemetry devices and randomized to treatment with either IgG or TLR4 neutralizing antibodies. Untreated control male SHR have greater TLR4 protein expression in the kidney compared to females. However, treatment with TLR4 neutralizing antibody for 2 weeks did not significantly alter BP in either male or female SHR. Interestingly, neutralization of TLR4 increased renal CD3⁺ T cells in female SHR, with no alteration in CD4⁺ T cells or CD8⁺ T cells in either sex. Taken together, our data indicates that although male SHR have greater renal TLR4 expression than females, TLR4 does not contribute to the higher BP and more pro-inflammatory renal T cell prolife in males vs. females.

MyD88: At the heart of inflammatory signaling and cardiovascular disease

Cardiovascular disease is a leading cause of death worldwide and is associated with systemic inflammation. In depth study of the cell-specific signaling mechanisms mediating the inflammatory response is vital to improving anti-inflammatory therapies that reduce mortality and morbidity. Cellular damage in the cardiovascular system results in the release of damage associated molecular patterns (DAMPs), also known as "alarmins," which activate myeloid cells through the adaptor protein myeloid differentiation primary response 88 (MyD88). MyD88 is broadly expressed in most cell types of the immune and cardiovascular systems, and its role often differs in a cardiovascular disease context and cell specific manner. Herein we review what is known about MyD88 in the setting of a variety of cardiovascular diseases, discussing cell specific functions and the relative contributions of MyD88-dependent vs. independent alarmin triggered inflammatory signaling. The widespread involvement of these pathways in cardiovascular disease, and their largely unexplored complexity, sets the stage for future in depth mechanistic studies that may place MyD88 in both immune and non-immune cell types as an attractive target for therapeutic intervention in cardiovascular disease.

TLR4-Myd88 pathway upregulated caveolin-1 expression contributes to coronary artery spasm

AIM

To study the role of toll-like receptors 4-myeloid differentiation factor 88 (TLR4-Myd88) dependent caveolin-1 (Cav-1) expression modulation in coronary artery spasm (CAS) and explore the underlying pathogenic mechanisms.

METHODS AND RESULTS

Lipopolysaccharide (LPS) and acetylcholine (Ach) were used to develop the in vitro and in vivo models mimicking the physiological CAS microenvironment. LPS-induced upregulation of Cav-1 expression in mouse coronary and aorta endothelial cells was shown by western blot and immunofluorescence (IF) staining (p < 0.01). Caveolin-1-knockout (Cav-1^-/-) mice had reduced aortic inflammation after LPS challenge, and fewer ST segment changes were observed through electrocardiogram (ECG) monitoring compared to wild type mice after LPS and ACh administration. In vitro, pretreating human umbilical vein endothelial cells (HUVECs) with siCav-1 to knock down Cav-1 expression reduced the endothelial inflammation following LPS challenge. SiCav-1 also partially reversed the attenuated Ca²⁺ concentration after LPS and ACh administration compared to the control group, which was evaluated by fluorescent molecular probing for Ca²⁺ alternation monitoring (p < 0.05). TLR4 and Myd88 downregulation by siRNA partially blocked the increased Cav-1 mRNA and protein expressions following LPS treatment, as well as partially reversed the decreased NO production evaluated by nitrate reductase method and the impaired Ca²⁺ concentration of endothelial cells induced by LPS and ACh.

CONCLUSION

These findings suggested that Cav-1, which was upregulated by TLR4-Myd88, served as an important modulator of CAS microenvironment establishment in vivo and in vitro, making it a potential pharmacologic target for the treatment of vasospasm via reduced endothelial cell inflammation.

Therapeutic targeting of inflammation in hypertension: from novel mechanisms to translational perspective

Both animal models and human observational and genetic studies have shown that immune and inflammatory mechanisms play a key role in hypertension and its complications. We review the effects of immunomodulatory interventions on blood pressure, target organ damage, and cardiovascular risk in humans. In experimental and small clinical studies, both non-specific immunomodulatory approaches, such as mycophenolate mofetil and methotrexate, and medications targeting T and B lymphocytes, such as tacrolimus, cyclosporine, everolimus, and rituximab, lower blood pressure and reduce organ damage. Mechanistically targeted immune interventions include isolevuglandin scavengers to prevent neo-antigen formation, co-stimulation blockade (abatacept, belatacept), and anti-cytokine therapies (e.g. secukinumab, tocilizumab, canakinumab, TNF-α inhibitors). In many studies, trial designs have been complicated by a lack of blood pressure-related endpoints, inclusion of largely normotensive study populations, polypharmacy, and established comorbidities. Among a wide range of interventions reviewed, TNF-α inhibitors have provided the most robust evidence of blood pressure lowering. Treatment of periodontitis also appears to deliver non-pharmacological anti-hypertensive effects. Evidence of immunomodulatory drugs influencing hypertension-mediated organ damage are also discussed. The reviewed animal models, observational studies, and trial data in humans, support the therapeutic potential of immune-targeted therapies in blood pressure lowering and in hypertension-mediated organ damage. Targeted studies are now needed to address their effects on blood pressure in hypertensive individuals.

Valsartan Prevented Neointimal Hyperplasia and Inhibited SRSF1 Expression and the TLR4-iNOS-ERK-AT1 Receptor Pathway in the Balloon-injured Rat Aorta

Valsartan has the potential to attenuate neointimal hyperplasia and to suppress the inflammatory response. This study aimed to evaluate the role of valsartan in neointimal hyperplasia and the toll-like receptor 4 (TLR4)-nitric oxide synthase (NOS) pathway in the balloon-injured rat aorta.Forty-eight Wistar rats were randomly allocated to three groups: sham control (control), balloon-injured group (surgery), and balloon-injured+valsartan-treated group (valsartan). Rats were killed at 14 and 28 days after balloon-injury, and then the aortic tissues were collected for morphometric analysis as well as for measurements of the mRNA or protein expression of angiotensin II, angiotensin II type 1 (AT1) receptor, angiotensin II type 2 (AT2) receptor, TLR4, endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), serine/arginine-rich splicing factor 1(SRSF1) and extracellular signal regulated kinase (ERK). Valsartan at a dose of 20 mg/kg/day markedly decreased neointimal hyperplasia in the aorta of balloon-injured rats, and significantly reduced the mRNA or protein expression of TLR4, AT1 receptor, SRSF1 and phosphorylated-ERK (p-ERK) as well as the aortic levels of iNOS (all p < 0.05). Moreover, valsartan increased the eNOS level and AT2 receptor mRNA and protein expression levels (all p < 0.05). Valsartan prevented neointimal hyperplasia and inhibited SRSF1 expression and the TLR4-iNOS-ERK-AT1 receptor pathway in the balloon-injured rat aorta.

Exposure to multiple metals and the risk of hypertension in adults: A prospective cohort study in a local area on the Yangtze River, China

BACKGROUND

Exposure to multiple metals is recognized as a common and real scenario in daily life. However, limited prospective studies have assessed associations between multiple metals exposure and hypertension.

METHODS

In total, 2625 adults in a local area on the Yangtze River were investigated at baseline from 2014 to 2015 and followed up in 2019. We measured baseline urine levels of 22 metals and used multivariate logistic analysis and Bayesian kernel machine regression (BKMR) to explore associations between multiple metals exposure and the risk of hypertension.

RESULTS

A total of 385 individuals (29.6%) were diagnosed with hypertension. Five metals (cadmium, copper, magnesium, molybdenum and zinc) were positively associated with hypertension in single-metal models. Cadmium and zinc remained significantly positive associations after adjusting for these five metals, with the odds ratio (OR) in the highest quartiles of 1.49 (95% CI: 1.01, 2.21; p-trend = 0.05) and 1.60 (95% CI: 1.08, 2.38; p-trend = 0.02), respectively. BKMR analysis showed a significant joint effect of multiple metals on hypertension when the concentrations of five metals were at or above their 55th percentile compared with their median values. A potential interaction between cadmium and zinc in increasing the risk of hypertension was observed with the OR_int of 1.41 (95%CI: 1.05, 1.89).

CONCLUSIONS

We identified the joint effect of multiple metals on hypertension and observed a significant interaction between cadmium and zinc. Further cohort studies are needed to clarify the health effects of multiple metals exposure in a larger population.

Effects of different intensities of continuous training on vascular inflammation and oxidative stress in spontaneously hypertensive rats

We aimed to study the effects and underlying mechanism of different intensities of continuous training (CT) on vascular inflammation and oxidative stress in spontaneously hypertensive rats (SHR). Rats were divided into five groups (n = 12): Wistar‐Kyoto rats sedentary group (WKY‐S), sedentary group (SHR‐S), low‐intensity CT group (SHR‐L), medium‐intensity CT group (SHR‐M) and high‐intensity CT group (SHR‐H). Changes in body mass, heart rate and blood pressure were recorded. The rats were euthanized after 14 weeks, and blood and vascular tissue samples were collected. Haematoxylin and Eosin staining was used to observe the aortic morphology, and Western blot was used to detect the expression of mesenteric artery proteins. After CT, the mean arterial pressures improved in SHR‐L and SHR‐M and increased in SHR‐H compared with those in SHR‐S. Vascular inflammation and oxidative stress levels significantly subsided in SHR‐L and SHR‐M (p < 0.05), whereas in SHR‐H, only vascular inflammation significantly subsided (p < 0.05), and oxidative stress remained unchanged (p > 0.05). AMPK and SIRT1/3 expressions in SHR‐L and SHR‐M were significantly up‐regulated than those in SHR‐S (p < 0.05). These results indicated that low‐ and medium‐intensity CT can effectively reduce the inflammatory response and oxidative stress of SHR vascular tissue, and high‐intensity CT can improve vascular tissue inflammation but not oxidative stress.

Inflammatory Mechanisms Contributing to Endothelial Dysfunction

Maintenance of endothelial cell integrity is an important component of human health and disease since the endothelium can perform various functions including regulation of vascular tone, control of hemostasis and thrombosis, cellular adhesion, smooth muscle cell proliferation, and vascular inflammation. Endothelial dysfunction is encompassed by complex pathophysiology that is based on endothelial nitric oxide synthase uncoupling and endothelial activation following stimulation from various inflammatory mediators (molecular patterns, oxidized lipoproteins, cytokines). The downstream signaling via nuclear factor-κB leads to overexpression of adhesion molecules, selectins, and chemokines that facilitate leukocyte adhesion, rolling, and transmigration to the subendothelial space. Moreover, oscillatory shear stress leads to pro-inflammatory endothelial activation with increased monocyte adhesion and endothelial cell apoptosis, an effect that is dependent on multiple pathways and flow-sensitive microRNA regulation. Moreover, the role of neutrophil extracellular traps and NLRP3 inflammasome as inflammatory mechanisms contributing to endothelial dysfunction has recently been unveiled and is under further investigation. Consequently, and following their activation, injured endothelial cells release inflammatory mediators and enter a pro-thrombotic state through activation of coagulation pathways, downregulation of thrombomodulin, and an increase in platelet adhesion and aggregation owing to the action of von-Willebrand factor, ultimately promoting atherosclerosis progression.

Angiotensin-II activates vascular inflammasome and induces vascular damage

Angiotensin-II (Ang-II), a major target for treatment of cardiovascular disease, promotes cardiovascular dysfunction by directly modulating structure and function of vascular cells. Inflammasome components are expressed in the vasculature and are activated by specific stimuli. However, whether Ang-II activates the inflammasome in vascular cells or inflammasome activation contributes to Ang-II-induced vascular damage is still not fully elucidated. We tested the hypothesis that Ang-II induces endothelial dysfunction, vascular remodeling, and high blood pressure via inflammasome activation. C57BL6/J wild type (WT) and Caspase-1 knockout (Casp1-/-) mice were infused with vehicle or Ang-II for two weeks (490 ng/Kg/day) to determine whether the inflammasome contributes to vascular damage induced by Ang-II. Rat Aortic Vascular Smooth Muscle cells (RASMC) were used to determine if the interaction between Ang-II and inflammasomes causes migration and proliferation of vascular smooth muscle cells. Ex vivo studies revealed that Ang-II infusion induced vascular oxidative stress, endothelial dysfunction and vascular remodeling in WT mice. Casp1-/- mice were protected against Ang-II-induced vascular injury. In vitro experiments, Ang-II activated the NLRP3 inflammasome in RASMC, i.e. Ang-II increased Caspase-1 (Casp1) activity and cleavage of pro-interleukin (IL)-1β. MCC950 (NLRP3 receptor antagonist) prevented Ang-II-induced vascular migration and proliferation, but failed to reduce reactive oxygen species production. In conclusion, Ang-II leads to inflammasome activation in the vasculature contributing to endothelial dysfunction and vascular remodeling. Taken together, we place inflammasomes as a possible therapeutic target in conditions associated with increased Ang-II levels.

Renin-angiotensin system and inflammation update

The most classical view of the renin-angiotensin system (RAS) emphasizes its role as an endocrine regulator of sodium balance and blood pressure. However, it has long become clear that the RAS has pleiotropic actions that contribute to organ damage, including modulation of inflammation. Angiotensin II (Ang II) activates angiotensin type 1 receptors (AT1R) to promote an inflammatory response and organ damage. This represents the pathophysiological basis for the successful use of RAS blockers to prevent and treat kidney and heart disease. However, other RAS components could have a built-in capacity to brake proinflammatory responses. Angiotensin type 2 receptor (AT2R) activation can oppose AT1R actions, such as vasodilatation, but its involvement in modulation of inflammation has not been conclusively proven. Angiotensin-converting enzyme 2 (ACE2) can process Ang II to generate angiotensin-(1-7) (Ang-(1-7)), that activates the Mas receptor to exert predominantly anti-inflammatory responses depending on the context. We now review recent advances in the understanding of the interaction of the RAS with inflammation. Specific topics in which novel information became available recently include intracellular angiotensin receptors; AT1R posttranslational modifications by tissue transglutaminase (TG2) and anti-AT1R autoimmunity; RAS modulation of lymphoid vessels and T lymphocyte responses, especially of Th17 and Treg responses; interactions with toll-like receptors (TLRs), programmed necrosis, and regulation of epigenetic modulators (e.g. microRNAs and bromodomain and extraterminal domain (BET) proteins). We additionally discuss an often overlooked effect of the RAS on inflammation which is the downregulation of anti-inflammatory factors such as klotho, peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), transient receptor potential ankyrin 1 (TRPA1), SNF-related serine/threonine-protein kinase (SNRK), serine/threonine-protein phosphatase 6 catalytic subunit (Ppp6C) and n-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Both transcription factors, such as nuclear factor κB (NF-κB), and epigenetic regulators, such as miRNAs are involved in downmodulation of anti-inflammatory responses. A detailed analysis of pathways and targets for downmodulation of anti-inflammatory responses constitutes a novel frontier in RAS research.

Crosstalk of TLR4, vascular NADPH oxidase, and COVID-19 in diabetes: What are the potential implications?

Toll-like receptor 4 (TLR4) contributes to the pathophysiology of diabetes. This happens, at least in part, because TLR4 modulates the enzyme NADPH oxidase, a primary source of ROS in vascular structures. Increased oxidative stress disrupts key vascular signaling mechanisms and drives the progression of diabetes, elevating the likelihood of cardiovascular diseases. Recently, it has been shown that patients with diabetes are also at a higher risk of developing severe coronavirus disease 2019 (COVID-19). Given the importance of the interaction between TLR4 and NADPH oxidase to the disrupted diabetic vascular system, we put forward the hypothesis that TLR4-mediated NADPH oxidase-derived ROS might be a critical mechanism to help explain why this disparity appears in diabetic patients, but unfortunately, conclusive experimental evidence still lacks in the literature. Herein, we focus on discussing the pathological implications of this signaling communication in the diabetic vasculature and exploring this crosstalk in the context of diabetes-associated severe COVID-19.

Early life stress induces dysregulation of the heme pathway in adult mice

Early life stress (ELS) is associated with cardiovascular disease (CVD) risk in adulthood, but the underlying vascular mechanisms are poorly understood. Increased hemoglobin and heme have recently been implicated to mediate endothelial dysfunction in several vascular diseases. Chronic physiological stress is associated with alterations in the heme pathway that have been well-described in the literature. However, very little is known about the heme pathway with exposure to ELS or chronic psychosocial stress. Utilizing a mouse model of ELS, maternal separation with early weaning (MSEW), we previously reported that MSEW induces endothelial dysfunction via increased superoxide production. We reasoned that heme dysregulation may be one of the culprits induced by MSEW and sustained throughout adulthood; thus, we hypothesized that MSEW induces heme dysfunction. We investigated whether circulating levels of heme, a circulating pro-oxidant mediator, are increased by MSEW and examined the role of the heme metabolic pathway and heme homeostasis in this process. We found that circulating levels of heme are increased in mice exposed to MSEW and that plasma from MSEW mice stimulated higher superoxide production in cultured mouse aortic endothelial cells (MAECs) compared to plasma from normally reared mice. The heme scavenger hemopexin blunted this enhanced superoxide production. Splenic haptoglobin abundance was significantly lower and hemoglobin levels per red blood cell were significantly higher in MSEW versus control mice. These findings lead us to propose that ELS induces increased circulating heme through dysregulation of the haptoglobin-hemoglobin system representing a mechanistic link between ELS and CVD risk in adulthood.

Novel Targets for Hypertension Drug Discovery

PURPOSE OF REVIEW

Despite the availability of various medications and prescribing combination therapies, uncontrolled blood pressure and resistance are observed in more than 40% of patients. The purpose of this review is to discuss emerging novel approaches for the treatment of hypertension and propose future research and clinical directions.

RECENT FINDINGS

Hypertension is a common disease of the cardiovascular system which may arise solely or as a comorbidity of other disorders. It is a crucial risk factor for cardiovascular diseases such as coronary artery disease, myocardial infarction, congestive heart failure, renal failure, and stroke. The results from current literature regarding the novel approaches showed several targets that could be explored as potential therapeutic options. These include toll-like receptor 4, a critical regulator of angiotensin II-induced hypertension; protease-activated receptor 2, which promotes collagen deposition and inflammatory responses; chemerin, which causes metabolic and obesity-associated hypertension; apelin receptor; transient receptor potential melastatin; urotensin-II; and Tie2 receptor. This review discusses various targets and pathways that could be emerging pharmacological therapies for hypertension.

Toll-Like Receptors in the Pathogenesis of Essential Hypertension. A Forthcoming Immune-Driven Theory in Full Effect

Essential hypertension (EH) is a highly heterogenous disease with a complex etiology. Recent evidence highlights the significant contribution of subclinical inflammation, triggered and sustained by excessive innate immune system activation in the pathogenesis of the disease. Toll-like receptors (TLRs) have been implied as novel effectors in this inflammatory environment since they can significantly stimulate the production of pro-inflammatory cytokines, the migration and proliferation of smooth muscle cells and the generation of reactive oxygen species (ROS), facilitating a low-intensity inflammatory background that is evident from the very early stages of hypertension. Furthermore, the net result of their activation is oxidative stress, endothelial dysfunction, vascular remodeling, and finally, vascular target organ damage, which forms the pathogenetic basis of EH. Importantly, evidence of augmented TLR expression and activation in hypertension has been documented not only in immune but also in several non-immune cells located in the central nervous system, the kidneys, and the vasculature which form the pathogenetic core systems operating in hypertensive disease. In this review, we will try to highlight the contribution of innate immunity in the pathogenesis of hypertension by clarifying the deleterious role of TLR signaling in promoting inflammation and facilitating hypertensive vascular damage.

KV 1.3 channels are novel determinants of macrophage-dependent endothelial dysfunction in angiotensin II-induced hypertension in mice

BACKGROUND AND PURPOSE

K_V 1.3 channels are expressed in vascular smooth muscle cells (VSMCs), where they contribute to proliferation rather than contraction and participate in vascular remodelling. K_V 1.3 channels are also expressed in macrophages, where they assemble with K_V 1.5 channels (K_V 1.3/K_V 1.5), whose activation generates a K_V current. In macrophages, the K_V 1.3/K_V 1.5 ratio is increased by classical activation (M1). Whether these channels are involved in angiotensin II (AngII)-induced vascular remodelling, and whether they can modulate the macrophage phenotype in hypertension, remains unknown. We characterized the role of K_V 1.3 channels in vascular damage in hypertension.

EXPERIMENTAL APPROACH

We used AngII-infused mice treated with two selective K_V 1.3 channel inhibitors (HsTX[R14A] and [EWSS]ShK). Vascular function and structure were measured using wire and pressure myography, respectively. VSMC and macrophage electrophysiology were studied using the patch-clamp technique; gene expression was analysed using RT-PCR.

KEY RESULTS

AngII increased K_V 1.3 channel expression in mice aorta and peritoneal macrophages which was abolished by HsTX[R14A] treatment. K_V 1.3 inhibition did not prevent hypertension, vascular remodelling, or stiffness but corrected AngII-induced macrophage infiltration and endothelial dysfunction in the small mesenteric arteries and/or aorta, via a mechanism independent of electrophysiological changes in VSMCs. AngII modified the electrophysiological properties of peritoneal macrophages, indicating an M1-like activated state, with enhanced expression of proinflammatory cytokines that induced endothelial dysfunction. These effects were prevented by K_V 1.3 blockade.

CONCLUSIONS AND IMPLICATIONS

We unravelled a new role for K_V 1.3 channels in the macrophage-dependent endothelial dysfunction induced by AngII in mice which might be due to modulation of macrophage phenotype.

Evidence that angiotensin II does not directly stimulate the MD2-TLR4 innate inflammatory pathway

The renin-angiotensin system (RAS) plays a critical role in the regulation of blood pressure. Inappropriate activation of the RAS, particularly stimulation of the ACE-Ang II-AT1 receptor axis is a key factor in hypertension and AT1R antagonists (ARBs) are first line therapies in the treatment of cardiovascular disease (CVD). Accumulating evidence suggests that the Ang II-AT1R axis may stimulate both innate and adaptive immune systems. Indeed, recent studies suggest that Ang II stimulates inflammatory events in an AT1R-independent manner by binding the MD2 accessory protein of the TLR4 complex in renal NRK-52E cells. Direct Ang II stimulation of the TLR4 complex is clinically relevant as ARBs increase circulating Ang II levels. Thus, the current study further investigated Ang II stimulation of the TLR4 pathway to release of the pro-inflammatory cytokine CCL2 under identical conditions to the TLR4 ligands LPS and palmitate in the NRK-52E cells. Although LPS (1 ng/mL) and palmitate (100 μM) stimulated CCL2 release 20-fold, Ang II (0.1-10 μM) failed to induce CCL2 release. Both the LPS and palmitate CCL2 responses were abolished by the TLR4 inhibitor Tak242 and significantly reduced by the MD2 inhibitor L48H37. Ang II (1 μM) had no additive effects on LPS (1 ng/mL) or palmitate (100 μM), and the ARB candesartan failed to attenuate CCL2 release to either agent alone. Ang II also failed to induce the release of the putative TLR4 ligand HMBG1. These studies failed to confirm that Ang II directly stimulates the MD2-TLR4 complex to induce cytokine release in NRK-52E cells.

TLR4 regulates vascular smooth muscle cell proliferation in hypertension via modulation of the NLRP3 inflammasome

Backgroud: Toll-like receptor 4 (TLR4), a key mediator of inflammatory responses, which is associated with vascular remodeling. The association between TLR4 and NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in the regulation of vascular smooth muscle cell (VSMC) proliferation remains unclear. This study was to explore the role and underlying mechanisms of TLR4 in the proliferation of VSMC in hypertension.

METHODS

VSMC proliferation after TLR4 overexpression or downregulation was determined by CCK-8, EdU Incorporation and colony formation assays. Western blots were carried out to investigate the expression of TLR4 and NLRP3 inflammasome components in VSMCs. Next, blood pressure measurements and Hematoxylin and Eosin (HE) staining assays were performed in spontaneously hypertensive rats (SHR). Media thickness (M) and diameter lumen (L) were measured as indicators of vascular remodeling. The expression of TLR4, PCNA and NLRP3 inflammasome complex was analyzed by Western blots in the aorta of SHR.

RESULTS

We showed that TLR4 overexpression with cDNA enhanced, while knockdown of TLR4 with shRNA inhibited Ang II-induced VSMC proliferation. Besides, TLR4 overexpression upregulated the proteion expression of the NLRP3 inflammasome components including NLRP3, ASC and caspase-1, whereas their corresponding levels of expression were observed to decrease in TLR4 shRNA-transfected VSMCs. Knockdown of TLR4 attenuated vascular remodeling, blood pressure (BP) and the levels of NLRP3, ASC, caspase-1, IL-1β and IL-18 in SHR aortas.

CONCLUSION

This study revealed that TLR4 regulated Ang II-induced VSMC proliferation through modulating the NLRP3 inflammasome. Knockdown of TLR4 attenuated the BP and vascular remodeling by inhibiting the expression of the NLRP3 inflammasome component in SHR. Our results support that TLR4 regulates VSMC proliferation in hypertension via triggering the NLRP3 inflammasome.

Improvement of intestinal flora: accompany with the antihypertensive effect of electroacupuncture on stage 1 hypertension

BACKGROUND

Increasing evidence have indicated the relationship between intestinal dysbiosis and hypertension. We aimed to evaluate the effect of the electroacupuncture (EA) on intestinal microbiota in patients with stage 1 hypertension.

METHODS

93 hypertensive patients and 15 healthy subjects were enrolled in this study. Applying a highly accurate oscillometric device to evaluate the antihypertensive effect of EA. 16S rRNA sequencing was used to profile stool microbial communities from Healthy group, Before treatment (BT) group and After treatment (AT) group, and various multivariate analysis approaches were used to assess diversity, composition and abundance of intestinal microbiota.

RESULTS

In this study, EA significantly decreased the blood pressure (BP) of hypertensive patients. Higher abundance of Firmicutes and lower Bacteroidetes abundance were observed in the BT group compared to the Healthy group. And EA treatment significantly decreased the Firmicutes/Bacteroidetes ratio compared to the BT group. Moreover, at the genus level, there was an increased abundance of Escherichia-Shigella in patients with hypertension, while Blautia were decreased, and EA reversed these changes.

CONCLUSIONS

Our study indicates that EA can effectively lower BP and improve the structure of intestinal microbiota which are correlate with the alteration of blood pressure by electroacupuncture.

TRIAL REGISTRATION

Clinicaltrial.gov, NCT01701726. Registered 5 October 2012, https://clinicaltrials.gov/ct2/show/study/NCT01701726.

Deficit of glucocorticoid-induced leucine zipper amplifies angiotensin-induced cardiomyocyte hypertrophy and diastolic dysfunction

Poor prognosis in heart failure and the lack of real breakthrough strategies validate targeting myocardial remodelling and the intracellular signalling involved in this process. So far, there are no effective strategies to counteract hypertrophy, an independent predictor of heart failure progression and death. Glucocorticoid-induced leucine zipper (GILZ) is involved in inflammatory signalling, but its role in cardiac biology is unknown. Using GILZ-knockout (KO) mice and an experimental model of hypertrophy and diastolic dysfunction, we addressed the role of GILZ in adverse myocardial remodelling. Infusion of angiotensin II (Ang II) resulted in myocardial dysfunction, inflammation, apoptosis, fibrosis, capillary rarefaction and hypertrophy. Interestingly, GILZ-KO showed more evident diastolic dysfunction and aggravated hypertrophic response compared with WT after Ang II administration. Both cardiomyocyte and left ventricular hypertrophy were more pronounced in GILZ-KO mice. On the other hand, Ang II-induced inflammatory and fibrotic phenomena, cell death and reduction in microvascular density, remained invariant between the WT and KO groups. The analysis of regulators of hypertrophic response, GATA4 and FoxP3, demonstrated an up-regulation in WT mice infused with Ang II; conversely, such an increase did not occur in GILZ-KO hearts. These data on myocardial response to Ang II in mice lacking GILZ indicate that this protein is a new element that can be mechanistically involved in cardiovascular pathology.

Arsenic Exposure and Incident Hypertension of Adult Residents Living in Rural Areas Along the Yangtze River, Anhui, China

OBJECTIVE

As a widespread toxic metal, arsenic had potential effect for hypertensive. We evaluated the association between urinary arsenic and the incidence of hypertension in adult residents along the Yangtze River of China.

METHODS

We conducted the study of 1358 adults 18 to 74 years of age from Chizhou, Maanshan, and Tongling of Anhui province, who participated in the baseline study in 2014 to 2015. Inductively coupled plasma optical emission spectrometry was used to measure urinary as of residents, and follow-up extended through 2016 to 2017.

RESULTS

We identified 275 hypertension events. The hazard ratios (HRs) of highest quartile arsenic compared with lowest quartile was 1.49 for hypertension events (95% confidence interval [CI] = 1.05 to 2.12), and HRs (≥P20 vs <P20) was 1.37 (95% CI = 1.02 to 1.84).

CONCLUSIONS

Higher level of arsenic exposure might play a role in increasing the incidence of hypertension.

Nox1/4 inhibition exacerbates age dependent perivascular inflammation and fibrosis in a model of spontaneous hypertension

Hypertension is associated with oxidative stress and perivascular inflammation, critical contributors to perivascular fibrosis and accelerated vascular ageing. Oxidative stress can promote vascular inflammation, creating options for potential use of NADPH oxidase inhibitors in pharmacological targeting of perivascular inflammation and its consequences.

Accordingly, we characterized age-related changes in oxidative stress and immune cell infiltration in normotensive (WKY) and spontaneously hypertensive rats (SHRs). Subsequently, we used pharmacological inhibitors of Nox1 (ML171) and Nox1/Nox4 (GKT137831; 60 mg/kg), to modulate NADPH oxidase activity at the early stage of spontaneous hypertension and investigated their effects on perivascular inflammation and fibrosis.

Results

Ageing was associated with a progressive increase of blood pressure as well as an elevation of the total number of leukocytes, macrophages and NK cells infiltrating perivascular adipose tissue (PVAT) in SHRs but not in WKY. At 1 month of age, when blood pressure was not yet different, only perivascular NK cells were significantly higher in SHR. Spontaneous hypertension was also accompanied by the higher perivascular T cell accumulation, although this increase was age independent. Aortic Nox1 and Nox2 mRNA expression increased with age only in SHR but not in WKY, while age-related increase of Nox4 mRNA in the vessels has been observed in both groups, it was more pronounced in SHRs. At early stage of hypertension (3-months) the most pronounced differences were observed in Nox1 and Nox4. Surprisingly, GKT137831, dual inhibitor of Nox1/4, therapy increased both blood pressure and perivascular macrophage infiltration. Mechanistically, this was linked to increased expression of proinflammatory chemokines expression (CCL2 and CCL5) in PVAT. This inflammatory response translated to increased perivascular fibrosis. This effect was likely Nox4 dependent as the Nox1 inhibitor ML171 did not affect the development of spontaneous hypertension, perivascular macrophage accumulation, chemokine expression nor adventitial collagen deposition.

In summary, spontaneous hypertension promotes ageing-associated perivascular inflammation which is exacerbated by Nox4 but not Nox1 pharmacological inhibition.

The role of Immunity in Fabry Disease and Hypertension: A Review of a Novel Common Pathway

Fabry disease is a progressive, X-linked inherited lysosomal storage disorder where accumulation of glycosphingolipids increases the risk for early cardiovascular complications, including heart failure, stroke, and end stage renal disease. Besides disease-specific therapy, blood pressure (BP) control is of central importance in Fabry disease to reduce disease progression and improve prognosis. Both Fabry disease and hypertension are characterized by the activation of the innate component of the immune system, with Toll-like receptor 4 (TLR4) as a common trigger to the inflammatory cascade. The renin-angiotensin system (RAS) participates in the establishment of low-grade chronic inflammation and redox unbalance that contribute to organ damage in the long term. Besides exploiting the anti-inflammatory effects of RAS blockade and enzyme replacement therapy, targeted therapies acting on the immune system represent an appealing field of research in these conditions. The aim of this narrative review is to examine the issue of hypertension in the setting of Fabry disease, focusing on the possible determinants of their reciprocal relationship, as well as on the related clinical and therapeutic implications.

Spent Hen Protein Hydrolysate with Good Gastrointestinal Stability and Permeability in Caco-2 Cells Shows Antihypertensive Activity in SHR

Spent hens are a major byproduct of the egg industry but are rich in muscle proteins that can be enzymatically transformed into bioactive peptides. The present study aimed to develop a spent hen muscle protein hydrolysate (SPH) with antihypertensive activity. Spent hen muscle proteins were hydrolyzed by nine enzymes, either individually or in combination; 18 SPHs were assessed initially for their in vitro angiotensin-converting enzyme (ACE) inhibitory activity, and three SPHs, prepared by Protex 26L (SPH-26L), pepsin (SPH-P), and thermoase (SPH-T), showed promising activity and peptide yield. These three hydrolysates were further assessed for their angiotensin-converting enzyme 2 (ACE2) upregulating, antioxidant, and anti-inflammatory activities; only SPH-T upregulated ACE2 expression, while all three SPHs showed antioxidant and anti-inflammatory activities. During simulated gastrointestinal digestion, ACE2 upregulating, ACE inhibitory and antioxidant activities of SPH-T were not affected, but those of SPH-26L and SPH-P were reduced. ACE inhibitory activity of gastrointestinal-digested SPH-T was not affected after the permeability study in Caco-2 cells, while ACE2 upregulating, antioxidant and anti-inflammatory activities were improved; nine novel peptides with five–eight amino acid residues were identified from the Caco-2 permeate. Among these three hydrolysates, only SPH-T reduced blood pressure significantly when given orally at a daily dose of 1000 mg/kg body weight to spontaneously hypertensive rats. SPH-T can be developed into a promising functional food ingredient against hypertension, contributing to a more sustainable utilization for spent hens while generating extra revenue for the egg industry.

Toll-like Receptor as a Molecular Link between Metabolic Syndrome and Inflammation: A Review

Metabolic Syndrome (MetS) involves a cluster of five conditions, i.e. obesity, hyperglycaemia, hypertension, hypertriglyceridemia and low High-Density Lipoprotein (HDL) cholesterol. All components of MetS share an underlying chronic inflammatory aetiology, manifested by increased levels of pro-inflammatory cytokines. The pathogenic role of inflammation in the development of MetS suggested that toll-like receptor (TLR) activation may trigger MetS. This review summarises the supporting evidence on the interactions between MetS and TLR activation, bridged by the elevation of TLR ligands during MetS. The regulatory circuits mediated by TLR activation, which modulates signal propagation, leading to the state of chronic inflammation, are also discussed. Taken together, TLR activation could be the molecular basis in the development of MetS-induced inflammation.

Toll-Like Receptors Contribute to Sex Differences in Blood Pressure Regulation

Toll-like receptors (TLRs) play an important role in the innate immune system, and recently, they have been shown to be involved in the regulation of blood pressure. The incidence of hypertension is higher in men, and it increases in postmenopausal women. In fact, premenopausal women are protected from cardiovascular disease compared with age-matched men, and it is well established that this protective effect is lost with menopause. However, the molecular mechanisms underlying this protection in women are unknown. Whether or not it could be related to differential activation of the innate immune system remains to be elucidated. This review focuses on (1) the differences between men and women in TLR activation and (2) whether TLR activation may influence the regulation of blood pressure in a sex-dependent manner.

Blockade of the TLR4-MD2 complex lowers blood pressure and improves vascular function in a murine model of type 1 diabetes

While the pathogenesis of diabetes-induced high blood pressure (BP) is not entirely clear, current evidence suggests that Toll-like receptor 4 (TLR4) is a key player in the mechanisms associated with hypertension. However, it is unknown whether this receptor affects BP under type 1 diabetes. Likewise, there is insufficient knowledge about the role of TLR4 in diabetes-associated vascular dysfunction of large arteries. To narrow these gaps, in this study, we investigated if blockade of the TLR4-MD2 complex impacts BP and vascular function in diabetic rats. We injected streptozotocin in male Sprague Dawley rats and treated them with a neutralizing anti-TLR4 antibody for 14 days. BP was directly measured in conscious animals at the end of the treatment. In another set of experiments, we excised the aorta from control and diabetic animals, and measured TLR4 and MD2—a co-receptor that confers functionality to TLR4—levels by Western blotting. We also performed functional studies and evaluated ROS levels with and without a pharmacological inhibitor for TLR4 as well as for MD2. Additionally, we scrutinized a large human RNA-Seq dataset of aortic tissue to assess the co-expression of TLR4, MD2, and subunits of the vascular NADPH oxidases under diabetes and hypertension. We report that (a) chronic blockade of the TLR4–MD2 complex lowers BP in diabetic animals; that (b) type 1 diabetes modulates the levels of MD2 expression in the aorta, but not TLR4, at least in the conditions evaluated in this study; and, that (c) acute inhibition of TLR4 or MD2 diminishes vascular contractility and reduces oxidative stress in the aorta of these animals. In summary, we show evidence that the TLR4–MD2 complex is involved in the mechanisms linking type 1 diabetes and hypertension.

Ketogenic diet aggravates hypertension via NF-κB-mediated endothelial dysfunction in spontaneously hypertensive rats

AIMS

Ketogenic diet (KD) has been proposed to be an effective lifestyle intervention for metabolic syndrome. However, the effects of KD on hypertension have not been well investigated. The present study aimed to investigate the effects and underling mechanisms of KD on hypertension in spontaneously hypertensive rats (SHRs).

MATERIALS AND METHODS

SHRs were subjected to normal diet or KD for 4 weeks, starting at the age of 10 weeks. Then, the blood pressure and vascular function were assessed. Next, the eNOS expression, inflammatory factors and relative signaling pathway were examined. Human umbilical vein endothelial cells were used to investigate the underlying mechanism account for the effect of ketone on inflammation and eNOS expression.

KEY FINDINGS

Compared with the normal diet, KD was indicated to aggravate hypertension and impaire endothelium-dependent relaxation in mesenteric arteries of SHRs. eNOS and CD31 expression in mesenteric arteries were also significantly suppressed by KD. In addition, KD markedly increased the activation of NF-κB pathway and the expression of IL1-β and TNF-α. In vitro, results showed that inhibition of NF-κB could rescue the adverse effects of ketone body and TGF-β on eNOS expression and inflammation response.

SIGNIFICANCE

Our study indicated that KD impaired endothelium-dependent relaxation in mesenteric arteries and aggravated the development of hypertension in SHRs, suggesting that it should be more cautious to apply KD into clinical application in hypertensive individuals.

Brain Angiotensin Type-1 and Type-2 Receptors in Physiological and Hypertensive Conditions: Focus on Neuroinflammation

PURPOSE OF REVIEW

To review recent data that suggest opposing effects of brain angiotensin type-1 (AT1R) and type-2 (AT2R) receptors on blood pressure (BP). Here, we discuss recent studies that suggest pro-hypertensive and pro-inflammatory actions of AT1R and anti-hypertensive and anti-inflammatory actions of AT2R. Further, we propose mechanisms for the interplay between brain angiotensin receptors and neuroinflammation in hypertension.

RECENT FINDINGS

The renin-angiotensin system (RAS) plays an important role in regulating cardiovascular physiology. This includes brain AT1R and AT2R, both of which are expressed in or adjacent to brain regions that control BP. Activation of AT1R within those brain regions mediate increases in BP and cause neuroinflammation, which augments the BP increase in hypertension. The fact that AT1R and AT2R have opposing actions on BP suggests that AT1R and AT2R may have similar opposing actions on neuroinflammation. However, the mechanisms by which brain AT1R and AT2R mediate neuroinflammatory responses remain unclear. The interplay between brain angiotensin receptor subtypes and neuroinflammation exacerbates or protects against hypertension.

NADPH Oxidases and Their Role in Atherosclerosis

The current view on atherosclerosis positions it as a multifactorial disorder that results from the interplay between lipid metabolism disturbances and inflammatory processes. Oxidative stress is proven to be one of the initiating factors in atherosclerosis development, being implicated both in the inflammatory response and in atherogenic modifications of lipoproteins that facilitate lipid accumulation in the arterial wall. The hallmark of oxidative stress is the elevated level of reactive oxygen species (ROS). Correspondingly, the activity of major ROS-generating enzymes, including nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, xanthine oxidases, and cyclooxygenases, is an important element in atherosclerosis development. In particular, the role of NADPH oxidases in atherosclerosis development has become a subject of intensive research. Aberrant activity of NADPH oxidases was shown to be associated with cardiovascular disease in humans. With regard to atherosclerosis, several important pathological components of the disease development, including endothelial dysfunction, inflammation, and vascular remodeling, involve aberrations in NADPH oxidases functioning. In humans, NADPH oxidases are represented by four isoforms expressed in vascular tissues, where they serve as the main source of ROS during atherogenesis. Moreover, recent studies have demonstrated their impact on vascular remodeling processes. Interestingly, one of the NADPH oxidase isoforms, NOX4, was shown to have an atheroprotective effect. Despite the growing evidence of the crucial involvement of NADPH oxidases in atherosclerosis pathogenesis, the available data still remains controversial. In this narrative review, we summarize the current knowledge of the role of NADPH oxidases in atherosclerosis and outline the future directions of research.

Association of chronic inflammation and accelerated atherosclerosis among an indigenous black population with chronic kidney disease

Introduction

Inflammation plays a major role in the development of atherosclerosis and cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. Toll-like receptor-4 (TLR4) is a major receptor for lipopolysaccharides (endotoxin) and other ligands involved in the pathogenesis of inflammation. We determined whether endotoxin levels and the presence of TLR4 polymorphisms are associated with markers of inflammation and atherosclerosis among South African CKD patients.

Materials and methods

Endotoxin, lipopolysaccharide binding protein (LBP), serum CD14 (sCD14), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and carotid intima media thickness (CIMT) were measured in 160 participants (120 CKD patients and 40 controls). Associations between endotoxins and CIMT in the presence of sCD14, IL-8 and MCP-1, were assessed using odds ratios. Participants were screened for the presence of Asp299Gly and Thr399Ile TLR4 polymorphisms, and CIMT and inflammatory markers were compared between subjects with and without TLR4 polymorphisms.

Results

Endotoxin levels correlated with sCD14 (r = 0.441, p<0.001) and MCP-1 (r = 0.388, p<0.001) levels while increased CIMT was associated with MCP-1 (r = 0.448, p<0.001), sCD14 levels (r = 0.476, p<0.001), LBP (r = 0.340, p<0.001), and IL-8 (r = 0.395, p<0.001). Atherosclerosis was associated with endotoxin levels (odds ratio: 4.95; 95% confidence interval: 2.52–9.73; p<0.001), and was predicted by higher serum levels of inflammatory markers. Analysis of patients with TLR4 polymorphisms showed reduced serum levels of inflammatory markers and CIMT values compared with the patients carrying the wild type TLR4 alleles.

Conclusion

The study demonstrated associations between circulating endotoxaemia, systemic inflammation and accelerated atherosclerosis among South African CKD patients, and showed that the atherogenic predictive power of endotoxaemia was significantly increased by the presence of elevated levels of inflammatory markers. Additional findings, which must be confirmed, suggest that TLR4 polymorphisms are associated with low levels of inflammatory markers and CIMT values.