Vascular inflammatory cells in hypertension

Deacetylation mimetic mutation of mitochondrial SOD2 attenuates ANG II-induced hypertension by protecting against oxidative stress and inflammation

Almost one-half of adults have hypertension, and blood pressure is poorly controlled in a third of patients despite the use of multiple drugs, likely because of mechanisms that are not affected by current treatments. Hypertension is linked to oxidative stress; however, common antioxidants are ineffective. Hypertension is associated with inactivation of key intrinsic mitochondrial antioxidant, superoxide dismutase 2 (SOD2), due to hyperacetylation, but the role of specific SOD2 lysine residues has not been defined. Hypertension is associated with SOD2 acetylation at lysine 68, and we suggested that deacetylation mimetic mutation of K68 to arginine in SOD2 inhibits vascular oxidative stress and attenuates hypertension. To test this hypothesis, we have developed a new deacetylation mimetic SOD2-K68R mice. We performed in vivo studies in SOD2-K68R mice using angiotensin II (ANG II) model of vascular dysfunction and hypertension. ANG II infusion in wild-type mice induced vascular inflammation and oxidative stress and increased blood pressure to 160 mmHg. SOD2-K68R mutation completely prevented increase in mitochondrial superoxide, abrogated vascular oxidative stress, preserved endothelial nitric oxide production, protected vasorelaxation, and attenuated ANG II-induced hypertension. ANG II and cytokines contribute to vascular oxidative stress and hypertension. Treatment of wild-type aortas with ANG II and cytokines in organoid culture increased mitochondrial superoxide twofold, which was completely prevented in aortas isolated from SOD2-K68R mice. These data support the important role of SOD2-K68 acetylation in vascular oxidative stress and pathogenesis of hypertension. We conclude that strategies to reduce SOD2 acetylation may have therapeutic potential in the treatment of vascular dysfunction and hypertension.NEW & NOTEWORTHY Essential hypertension is associated with hyperacetylation of key mitochondrial antioxidant SOD2; however, the pathophysiological role of SOD2 acetylation has not been defined. Our animal study of angiotensin II hypertension model shows that deacetylation mimetic SOD2-K68R mutation prevents pathogenic increase in vascular mitochondrial superoxide, abrogates vascular oxidative stress, preserves endothelial nitric oxide, protects endothelial-dependent vasorelaxation, and attenuates hypertension. These data support the important role of SOD2-K68 acetylation in vascular oxidative stress and the pathogenesis of hypertension.

AT1b receptors contribute to regional disparities in angiotensin II mediated aortic remodelling in mice

The renin-angiotensin system plays a key role in regulating blood pressure, which has motivated many investigations of associated mouse models of hypertensive arterial remodelling. Such studies typically focus on histological and cell biological changes, not wall mechanics. This study explores tissue-level ramifications of chronic angiotensin II infusion in wild-type (WT) and type 1b angiotensin II (AngII) receptor null (Agtr1b -/-) mice. Biaxial biomechanical and immunohistological changes were quantified and compared in the thoracic and abdominal aorta in these mice following 14 and 28 days of angiotensin II infusion. Preliminary results showed that changes were largely independent of sex. Associated thickening and stiffening of the aortic wall in male mice differed significantly between thoracic and abdominal regions and between genotypes. Notwithstanding multiple biomechanical changes in both WT and Agtr1b -/- mice, AngII infusion caused distinctive wall thickening and inflammation in the descending thoracic aorta of WT, but not Agtr1b -/-, mice. Our study underscores the importance of exploring differential roles of receptor-dependent angiotensin II signalling along the aorta and its influence on distinct cell types involved in regional histomechanical remodelling. Disrupting the AT1b receptor primarily affected inflammatory cell responses and smooth muscle contractility, suggesting potential therapeutic targets.

Yoga Nidra for hypertension: A systematic review and meta-analysis

BACKGROUND

Hypertension is a prevalent chronic condition that affects a substantial proportion of the world's population. Medications are commonly prescribed for hypertension management, but non-pharmacological interventions like yoga are gaining popularity.

OBJECTIVE

The purpose of this systematic review and meta-analysis is to assess the efficacy of Yoga Nidra (YN) for the management of hypertension.

METHODS

A systematic review and meta-analysis of clinical trials, i.e., non-randomized and randomized controlled trials (RCTs) was conducted to investigate the effects of YN on hypertension. PubMed, the Cochrane Library, SCOPUS, and EBSCO were searched for relevant studies published up to September 2022. The quality of the included studies was assessed using the Cochrane risk of bias tool. The primary outcome measure was the change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) after YN intervention, analyzed as weighted mean difference (WMD), in comparison to control groups. The random-effects model was used for the meta-analysis. Risk of bias was assessed for RCTs and non-RCTs using Cochrane's RoB-2 and ROBINS-I tools, respectively.

RESULTS

Five RCTs and three Non-RCTs involving a total of 482 participants (239 for YN vs 243 for controls) were included in this review. The meta-analysis indicated that YN significantly reduced SBP (WMD = 12.03 mm Hg, 95% CI [7.12, 16.93], Z = 4.80, p < 0.00001) and DBP (WMD = 6.32 mm Hg, 95% CI [3.53, 9.12], Z = 4.43, p < 0.00001) compared to control groups. The overall risk of bias for the three RCTs was high, whereas for the five non-RCTs, one had an overall moderate risk while the other four had an overall serious risk of bias.

DISCUSSION

This systematic review and meta-analysis provides evidence supporting the efficacy of YN as a complementary therapy for hypertension management. YN is a safe, cost-effective, and easily accessible intervention that primarily relies on interoception and induces a deep relaxation response in practitioners, aiding them in coping with various components of high blood pressure, such as stress, vascular inflammation, peripheral vascular resistance, etc. Our understanding of the mechanisms of YN is constantly evolving, and there is a need for further research to fully explore and appreciate the significance of this ancient science and its potential efficacy on BP. Considering the results and the multifactorial role of YN, it can act as a safe and reliable adjuvant therapy to complement the pharmacological treatment of hypertension. However, further studies with larger sample sizes, longer follow-up periods, and homogenous populations are warranted.

CONCLUSION

This meta-analysis suggests that YN is effective in reducing SBP and DBP, particularly in individuals with hypertension. The results highlight the potential of YN as a complementary therapy for hypertension management. Healthcare providers may consider recommending YN to patients with hypertension as an adjuvant therapy to medication. Further studies are required to identify standardized optimal forms and durations of YN best suited for hypertension management.

Plasma Calprotectin Levels Associate With New-Onset Hypertension in the General Population: A Prospective Cohort Study

BACKGROUND

Low-grade systemic inflammation is a relevant pathogenic mechanism underlying the development of hypertension. In this study, we hypothesized that plasma calprotectin levels, as a biomarker of neutrophil-mediated inflammation, is associated with developing new-onset hypertension in the general population.

METHODS AND RESULTS

Plasma calprotectin levels were determined in 3524 participants who participated in the PREVEND (Prevention of Renal and Vascular End-Stage Disease) study, a prospective population-based cohort study. Plasma calprotectin levels were studied for associations with the risk of new-onset hypertension, defined as systolic blood pressure of at least 140 mm Hg, diastolic blood pressure of at least 90 mm Hg, or the first recorded use of antihypertensives. Participants with hypertension at baseline were excluded. Median plasma calprotectin levels were 0.48 (0.34-0.66) mg/L, and median systolic blood pressure was 117 (109-126) mm Hg. Plasma calprotectin levels were significantly associated with the risk of new-onset hypertension (hazard ratio [HR], per doubling 1.30 [95% CI, 1.21-1.41]; P<0.001), also after adjustment for age and sex (HR, 1.26 [95% CI, 1.16-1.37]; P<0.001), but not after additional adjustment for potentially confounding factors, including baseline systolic blood pressure (HR, 1.00 [95% CI, 0.90-1.11]; P=0.996). Stratified analyses showed significant effect modification by sex (Pinteraction=0.023) and urinary albumin excretion (Pinteraction=0.004), with higher HRs in men (compared with women) and in individuals with higher urinary albumin excretion (>9.3 mg per 24 hours) compared with lower urinary albumin excretion (≤9.3 mg per 24 hours).

CONCLUSIONS

Higher plasma calprotectin levels are associated with an increased risk of new-onset hypertension in the general population. This association is dependent on baseline systolic blood pressure and is particularly prominent in men compared with women.

Sodium accumulation in the skin is associated with higher density of skin lymphatic vessels in patients with arterial hypertension

PURPOSE

Recent studies, conducted mainly on the rodent model, have demonstrated that regulatory pathway in the skin provided by glycosaminoglycans, nuclear factor of activated T cells 5 (NFAT5), vascular endothelial growth factor C (VEGF-C) and process of lymphangiogenesis may play an important role in extrarenal regulation of sodium (Na+) balance, body water volume, and blood pressure. We aimed to investigate the concentrations and relations among the main factors of this pathway in human skin to confirm that this regulatory axis also exists in humans.

PATIENTS AND METHODS

Skin specimens from patients diagnosed with arterial hypertension and from control group were histologically and molecularly examined.

RESULTS

The primary hypertensive and control groups did not differ in Na+ ​concentrations in the skin. However, the patients with hypertension and higher skin Na+ concentration had significantly greater density of skin lymphatic vessels. Higher skin Na+concentration was associated with higher skin water content. In turn, skin water content correlated with factors associated with lymphangiogenesis, i.e. NFAT5, VEGF-C, and podoplanin (PDPN) mRNA expression in the skin. The strong mutual pairwise correlations of the expressions of NFAT5, VEGF-C, vascular endothelial growth factor D (VEGF-D) and PDPN mRNA were noted in the skin in all of the studied groups.

CONCLUSIONS

Our study confirms that skin interstitium and the lymphatic system may be important players in the pathophysiology of arterial hypertension in humans. Based on the results of our study and existing literature in this field, we propose the hypothetical model which might explain the phenomenon of salt-sensitivity.

Vascular smooth muscle cell mechanotransduction through serum and glucocorticoid inducible kinase-1 promotes interleukin-6 production and macrophage accumulation in murine hypertension

Objective

The objective of this investigation was to demonstrate that in vivo induction of hypertension (HTN) and in vitro cyclic stretch of aortic vascular smooth muscle cells (VSMCs) can cause serum and glucocorticoid-inducible kinase (SGK-1)-dependent production of cytokines to promote macrophage accumulation that may promote vascular pathology.

Methods

HTN was induced in C57Bl/6 mice with angiotensin II infusion (1.46 mg/kg/day × 21 days) with or without systemic infusion of EMD638683 (2.5 mg/kg/day × 21 days), a selective SGK-1 inhibitor. Systolic blood pressure was recorded. Abdominal aortas were harvested to quantify SGK-1 activity (pSGK-1/SGK-1) by immunoblot. Flow cytometry quantified the abundance of CD11b+/F480+ cells (macrophages). Plasma interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) was assessed by enzyme-linked immunosorbent assay. Aortic VSMCs from wild-type mice were subjected to 12% biaxial cyclic stretch (Stretch) for 3 or 12 hours with or without EMD638683 (10 μM) and with or without SGK-1 small interfering RNA with subsequent quantitative polymerase chain reaction for IL-6 and MCP-1 expression. IL-6 and MCP-1 in culture media were analyzed by enzyme-linked immunosorbent assay. Aortic VSMCs from SGK-1flox+/+ mice were transfected with Cre-Adenovirus to knockdown SGK-1 (SGK-1KD VSMCs) and underwent parallel tension experimentation. Computational modeling was used to simulate VSMC signaling. Statistical analysis included analysis of variance with significance at a P value of <.05.

Results

SGK-1 activity, abundance of CD11b+/F4-80+ cells, and plasma IL-6 were increased in the abdominal aorta of mice with HTN and significantly reduced by treatment with EMD638683. This outcome mirrored the increased abundance of IL-6 in media from Stretch C57Bl/6 VSMCs and attenuation of the effect with EMD638683 or SGK-1 small interfering RNA. C57Bl/6 VSMCs also responded to Stretch with increased MCP-1 expression and secretion into the culture media. Further supporting the integral role of mechanical signaling through SGK-1, target gene expression and cytokine secretion was unchanged in SGK-1KD VSMCs with Stretch, and computer modeling confirmed SGK-1 as an intersecting node of signaling owing to mechanical strain and angiotensin II.

Conclusions

Mechanical activation of SGK-1 in aortic VSMCs can promote inflammatory signaling and increased macrophage abundance, therefore this kinase warrants further exploration as a pharmacotherapeutic target to abrogate hypertensive vascular pathology.

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio are Important Indicators for Predicting in-Hospital Death in Elderly AMI Patients

Aim

To investigate the role of neutrophil-to-lymphocyte ratio(NLR) and platelet-to-lymphocyte(PLR) in predicting the risk of in-hospital mortality in elderly acute myocardial infarction(AMI) patients.

Methods

This study was a single-center, retrospective and observational study. From December 2015 to December 2021, a total of 1550 elderly patients (age ≥ 60 years) with AMI with complete clinical history data were enrolled in the Second Hospital of Dalian Medical University. Routine blood tests were performed on admission, and NLR and PLR were calculated based on neutrophil, platelet, and lymphocyte counts. Outcome was defined as all-cause mortality during hospitalization. Cox regression and restricted spline cubic(RCS) models were used to evaluate the association of NLR and in-hospital mortality risk and the association of PLR with in-hospital mortality risk, respectively.

Results

(1) A total of 132 (8.5%) patients died during hospitalization. From the results of blood routine, the white blood cell, neutrophil, NLR and PLR in the death group were higher than those in the non-death group, while the lymphocyte was lower than that in the non-death group, and the difference was statistically significant (P < 0.05). (2) The results of receiver operating characteristic(ROC) curves analysis showed that the predictive ability of NLR (AUC = 0.790) for in-hospital death was better than that of PLR (AUC = 0.637). (3) Multivariate Cox proportional regression hazard models showed that high NLR was associated with the risk of in-hospital mortality in elderly AMI patients (HR = 3.091, 95% CI 2.097-4.557, P < 0.001), while high PLR was not. (4) RCS models showed a nonlinear dose-response relationship between NLR and in-hospital death (P for nonlinear = 0.0007).

Conclusion

High NLR (> 6.69) is associated with the risk of in-hospital mortality in elderly patients with AMI and can be an independent predictor of poor short-term prognosis in elderly patients with AMI.

Role of inflammation, immunity, and oxidative stress in hypertension: New insights and potential therapeutic targets

Hypertension is regarded as the most prominent risk factor for cardiovascular diseases, which have become a primary cause of death, and recent research has demonstrated that chronic inflammation is involved in the pathogenesis of hypertension. Both innate and adaptive immunity are now known to promote the elevation of blood pressure by triggering vascular inflammation and microvascular remodeling. For example, as an important part of innate immune system, classically activated macrophages (M1), neutrophils, and dendritic cells contribute to hypertension by secreting inflammatory cy3tokines. In particular, interferon-gamma (IFN-γ) and interleukin-17 (IL-17) produced by activated T lymphocytes contribute to hypertension by inducing oxidative stress injury and endothelial dysfunction. However, the regulatory T cells and alternatively activated macrophages (M2) may have a protective role in hypertension. Although inflammation is related to hypertension, the exact mechanisms are complex and unclear. The present review aims to reveal the roles of inflammation, immunity, and oxidative stress in the initiation and evolution of hypertension. We envisage that the review will strengthen public understanding of the pathophysiological mechanisms of hypertension and may provide new insights and potential therapeutic strategies for hypertension.

IFN-γ Contributes to the Immune Mechanisms of Hypertension

Hypertension is the leading cause of cardiovascular disease and the primary risk factor for mortality worldwide. For more than half a century, researchers have demonstrated that immunity plays an important role in the development of hypertension; however, the precise mechanisms are still under investigation. The current body of knowledge indicates that proinflammatory cytokines may play an important role in contributing to immune-related pathogenesis of hypertension. Interferon gamma (IFN-γ), in particular, as an important cytokine that modulates immune responses, has been recently identified as a critical regulator of blood pressure by several groups, including us. In this review, we focus on exploring the role of IFN-γ in contributing to the pathogenesis of hypertension, outlining the various immune producers of this cytokine and described signaling mechanisms involved. We demonstrate a key role for IFN-γ in hypertension through global knockout studies and related downstream signaling pathways that IFN-γ production from CD8+ T cell (CD8T) in the kidney promoting CD8T-stimulated salt retention via renal tubule cells, thereby exacerbating hypertension. We discuss potential activators of these T cells described by the current literature and relay a novel hypothesis for activation.

Highlights of mechanisms and treatment of obesity-related hypertension

The prevalence of obesity has increased two to three times from 1975 to 2015. Large-scale epidemiological and longitudinal prospective studies link obesity with hypertension. Research suggests that excessive weight gain, particularly when associated with visceral adiposity, may account for as much as 65% to 75% of the risk of incident hypertension. Also, exercise and bariatric/metabolic surgery significantly lowers blood pressure, whereas weight gain increases blood pressure, thus establishing a firm link between these two factors. The mechanisms underpinning obesity-related hypertension are complex and multifaceted, and include, but are not limited to, renin-angiotensin-aldosterone system/sympathetic nervous system overactivation, overstimulation of adipokines, insulin resistance, immune dysfunction, structural/functional renal, cardiac, and adipocyte changes. Though weight loss is the mainstay of treatment for obesity-related hypertension, it is often not a feasible long-term solution. Therefore, it is recommended that aggressive treatment with multiple antihypertensive medications combined with diet and exercise be used to lower blood pressure and prevent complications. The research regarding the mechanisms and treatment of obesity-related hypertension has moved at a blistering pace over the past ten years. Therefore, the purpose of this expert review is two-fold: to discuss the pathophysiological mechanisms underlying obesity-related hypertension, and to revisit pharmacotherapies that have been shown to be efficacious in patients with obesity-related hypertension.

Influenza A virus elicits peri-vascular adipose tissue inflammation and vascular dysfunction of the aorta in pregnant mice

Influenza A virus (IAV) infection during pregnancy initiates significant aortic endothelial and vascular smooth muscle dysfunction, with inflammation and T cell activation, but the details of the mechanism are yet to be clearly defined. Here we demonstrate that IAV disseminates preferentially into the perivascular adipose tissue (PVAT) of the aorta in mice. IAV mRNA levels in the PVAT increased at 1–3 days post infection (d.p.i) with the levels being ~4–8 fold higher compared with the vessel wall. IAV infection also increased Ly6C^low patrolling monocytes and Ly6C^high pro-inflammatory monocytes in the vessel wall at 3 d.p.i., which was then followed by a greater homing of these monocytes into the PVAT at 6 d.p.i. The vascular immune phenotype was characteristic of a “vascular storm”- like response, with increases in neutrophils, pro-inflammatory cytokines and oxidative stress markers in the PVAT and arterial wall, which was associated with an impairment in endothelium-dependent relaxation to acetylcholine. IAV also triggered a PVAT compartmentalised elevation in CD4⁺ and CD8⁺ activated T cells. In conclusion, the PVAT of the aorta is a niche that supports IAV dissemination and a site for perpetuating a profound innate inflammatory and adaptive T cell response. The manifestation of this inflammatory response in the PVAT following IAV infection may be central to the genesis of cardiovascular complications arising during pregnancy.

Influenza A virus (IAV) infection remains a major cause of significant disease during pregnancy. IAV infection in pregnancy results in virus dissemination from the lung to the systemic vasculature, thereby initiating profound vascular inflammation and T cell activation that leads to vascular damage. Currently, the details of the mechanism that facilitates this vascular pathology and the influence of IAV dissemination to the vasculature on the perivascular adipose tissue (PVAT) is not clearly defined. Here, we show that IAV disseminates to the PVAT compartment of the vessel at a much larger rate than the vessel wall. We found that IAV infection increased PVAT inflammation characterised by immune cell infiltration, oxidative stress and pro-inflammatory cytokines. This was accompanied by a preferential immune T cell activation in the PVAT. We also found that this vascular inflammatory burden results in vascular endothelial dysfunction that is characterised by an impairment in endothelium dependent relaxation. Our study provides new insights into how IAV utilises the PVAT to promote the vascular inflammatory pathology that disrupts the vasculature in pregnancy and lead to pregnancy complications.

Role of Posttranslational Modifications of Proteins in Cardiovascular Disease

Cardiovascular disease (CVD) has become a leading cause of mortality and morbidity globally, making it an urgent concern. Although some studies have been performed on CVD, its molecular mechanism remains largely unknown for all types of CVD. However, recent in vivo and in vitro studies have successfully identified the important roles of posttranslational modifications (PTMs) in various diseases, including CVD. Protein modification, also known as PTMs, refers to the chemical modification of specific amino acid residues after protein biosynthesis, which is a key process that can influence the activity or expression level of proteins. Studies on PTMs have contributed directly to improving the therapeutic strategies for CVD. In this review, we examined recent progress on PTMs and highlighted their importance in both physiological and pathological conditions of the cardiovascular system. Overall, the findings of this review contribute to the understanding of PTMs and their potential roles in the treatment of CVD.

Immune System and Microvascular Remodeling in Humans

Low-grade inflammatory processes and related oxidative stress may have a key role in the pathogenesis of hypertension and hypertension-mediated organ damage. Innate immune cells, such as neutrophils, dendritic cells, monocytes/macrophages, as well as unconventional T lymphocytes like γδ T cells contribute to hypertension and may trigger vascular inflammation. Adaptive immunity has been demonstrated to participate in elevation of blood pressure and in vascular and kidney injury. In particular, effector T lymphocytes (Th1, Th2, and Th17) may play a relevant role in promoting hypertension and microvascular remodeling, whereas T-regulatory lymphocytes may have a protective role. Effector cytokines produced by these immune cells lead to increased oxidative stress, endothelial dysfunction and contribute to target organ damage in hypertension. A possible role of immune cell subpopulations in the development and regression of microvascular remodeling has also been proposed in humans with hypertension. The present review summarizes the key immune mechanisms that may participate in the pathophysiology of hypertension-mediated inflammation and vascular remodeling; advances in this field may provide the basis for novel therapeutics for hypertension.

E-Selectin Is Associated with Daytime and 24-Hour Diastolic Blood Pressure Variability in Type 2 Diabetes

E-selectin is an endothelial cell adhesion molecule involved in vascular inflammation. Elevated E-selectin has been reported in patients with high blood pressure and diabetes. Given the increasing clinical relevance of parameters derived from ambulatory blood pressure monitoring, further investigation of their relationships with E-selectin is of interest. In this study, we aimed to investigate the association between serum E-selectin, office blood pressure and 24 h ambulatory blood pressure parameters in patients with type 2 diabetes. Blood pressure variability was assessed by computing the standard deviation of mean systolic and diastolic blood pressure separately for daytime and nighttime during 24 h ambulatory blood pressure monitoring in a cohort of patients with type 2 diabetes (n = 132). Additionally, were assessed nighttime systolic dipping and pulse pressure separately for daytime, nighttime, and 24 h. Serum E-selectin was measured using the enzyme-linked immunosorbent assay technique. We found that E-selectin was consistently associated with 24 h diastolic blood pressure variability (r = 0.238; p = 0.019) and daytime diastolic blood pressure variability (r = 0.258; p = 0.012), after adjustment for confounding factors. No association of E-selectin with office blood pressure and other 24 h ambulatory blood pressure parameters was observed. In conclusion, endothelial activation indicated by elevated serum E-selectin is associated with increased ambulatory diastolic blood pressure variability in patients with type 2 diabetes.

MEKK3-TGFβ crosstalk regulates inward arterial remodeling

Arterial remodeling is an important adaptive mechanism that maintains normal fluid shear stress in a variety of physiologic and pathologic conditions. Inward remodeling, a process that leads to reduction in arterial diameter, plays a critical role in progression of such common diseases as hypertension and atherosclerosis. Yet, despite its pathogenic importance, molecular mechanisms controlling inward remodeling remain undefined. Mitogen-activated protein kinases (MAPKs) perform a number of functions ranging from control of proliferation to migration and cell-fate transitions. While the MAPK ERK1/2 signaling pathway has been extensively examined in the endothelium, less is known about the role of the MEKK3/ERK5 pathway in vascular remodeling. To better define the role played by this signaling cascade, we studied the effect of endothelial-specific deletion of its key upstream MAP3K, MEKK3, in adult mice. The gene's deletion resulted in a gradual inward remodeling of both pulmonary and systematic arteries, leading to spontaneous hypertension in both vascular circuits and accelerated progression of atherosclerosis in hyperlipidemic mice. Molecular analysis revealed activation of TGFβ-signaling both in vitro and in vivo. Endothelial-specific TGFβR1 knockout prevented inward arterial remodeling in MEKK3 endothelial knockout mice. These data point to the unexpected participation of endothelial MEKK3 in regulation of TGFβR1-Smad2/3 signaling and inward arterial remodeling in artery diseases.

Hypertension and its management in COVID-19 patients: The assorted view

BACKGROUND

Coronavirus disease 2019 (COVID-19) is suspected to mainly be more deleterious in patients with underlying cardiovascular diseases (CVD). There is a strong association between hypertension and COVID-19 severity. The binding of SARS-CoV-2 to the angiotensin-converting enzyme 2 (ACE2) leads to deregulation of the renin-angiotensin-aldosterone system (RAAS) through down-regulation of ACE2 with subsequent increment of the harmful Ang II serum levels and reduction of the protective Ang-(1-7). Both angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) are commonly used to manage hypertension.

OBJECTIVE

Objective was to illustrate the potential link between hypertension and COVID-19 regarding the role of angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) in hypertensive patients with COVID-19.

METHODS

We carried out comprehensive databases search from late December 2019 to early January 2021 by using online engines of Web of Science, Research gate, Scopus, Google Scholar, and PubMed for published and preprinted articles.

RESULTS

The present study's findings showed that hypertension is regarded as an independent risk factor for COVID-19 severity. Both ACEIs and ARBs are beneficial in managing hypertensive patients.

CONCLUSION

This study concluded that hypertension increases COVID-19 severity due to underlying endothelial dysfunctions and coagulopathy. COVID-19 might augment the hypertensive complications due to down-regulation of ACE2. The use of ACEIs or ARBs might be beneficial in the management of hypertensive patients with COVID-19.

Sex-Based Differences in Autologous Cell Therapy Trials in Patients With Acute Myocardial Infarction: Subanalysis of the ACCRUE Database

Background: Sex-based differences are under-studied in cardiovascular trials as women are commonly underrepresented in dual sex studies, even though major sex-based differences in epidemiology, pathophysiology, and outcomes of cardiovascular disease have been reported. We examined sex-based differences in patient characteristics, outcome, and BM-CD34+ frequency of the ACCRUE (Meta-Analysis of Cell-based CaRdiac studies) database involving patients with acute myocardial infarction (AMI) randomized to autologous cell-based or control treatment. Methods: We compared baseline characteristics and 1-year follow-up clinical data: composite major adverse cardiac and cerebrovascular events (primary endpoint), and changes in left ventricular ejection fraction (LVEF), end-diastolic (EDV), and end-systolic volumes (ESV) (secondary efficacy endpoint) in women and men (N = 1,252; 81.4% men). Secondary safety endpoints included freedom from hard clinical endpoints. Results: In cell-treated groups, women but not men had a lower frequency of stroke, AMI, and mortality than controls. The frequency of BM-CD34+ cells was significantly correlated with baseline EDV and ESV and negatively correlated with baseline LVEF in both sexes; a left shift in regression curve in women indicated a smaller EDV and ESV was associated with higher BM-CD34+ cells in women. Conclusions: Sex differences were found in baseline cardiovascular risk factors and cardiac function and in outcome responses to cell therapy.

CRIP1 expression in monocytes related to hypertension

Hypertension is a complex and multifactorial disorder caused by lifestyle and environmental factors, inflammation and disease-related genetic factors and is a risk factor for stroke, ischemic heart disease and renal failure. Although circulating monocytes and tissue macrophages contribute to the pathogenesis of hypertension, the underlying mechanisms are poorly understood. Cysteine rich protein 1 (CRIP1) is highly expressed in immune cells, and CRIP1 mRNA expression in monocytes associates with blood pressure (BP) and is up-regulated by proinflammatory modulation suggesting a link between CRIP1 and BP regulation through the immune system. To address this functional link, we studied CRIP1 expression in immune cells in relation to BP using a human cohort study and hypertensive mouse models. CRIP1 expression in splenic monocytes/macrophages and in circulating monocytes was significantly affected by angiotensin II (Ang II) in a BP-elevating dose (2 mg/kg/day). In the human cohort study, monocytic CRIP1 expression levels were associated with elevated BP, whereas upon differentiation of monocytes to macrophages this association along with the CRIP1 expression level was diminished. In conclusion, CRIP1-positive circulating and splenic monocytes seem to play an important role in hypertension related inflammatory processes through endogenous hormones such as Ang II. These findings suggest that CRIP1 may affect the interaction between the immune system, in particular monocytes, and the pathogenesis of hypertension.

Restraint Stress in Hypertensive Rats Activates the Intestinal Macrophages and Reduces Intestinal Barrier Accompanied by Intestinal Flora Dysbiosis

Purpose

Hypertension (HTN) is a major risk factor for cardiovascular disease. In recent years, there were numerous studies on the function of stress in HTN. However, the gut dysbiosis linked to hypertension in animal models under stress is still incompletely understood. Purpose of this study is to use multiple determination method to determine the juvenile stage intestinal bacteria, cytokines and changes in hormone levels.

Methods

Four groups of juvenile male spontaneously hypertensive rats (SHRs) and age-matched male Wistar-Kyoto (WKY) rats were randomly selected as control and experimental groups. Rats in the two stress groups were exposed to restraint stress for 3 hours per day for 7 consecutive days. In one day three times in the method of non-invasive type tail-cuff monitoring blood pressure. The detailed mechanism was illuminated based on the intestinal change using immunohistochemical and immunofluorescence staining and the stress-related hormone and inflammation factors were analyzed via ELISA method. The integrity of the epithelial barrier was assessed using FITC/HRP and the expression levels of proteins associated with the tight junction was detected by Western blot. The alteration of stress-related intestinal flora from ileocecal junction and distal colon were also analyzed using its 16S rDNA sequencing.

Results

The results indicate that acute stress rapidly increases mean arterial pressure which is positive correlation to hormone concentration, especially in SHR-stress group. Meanwhile, stress promoted the enhancement of epithelial permeability accompanied with a reduced expression of the tight junction-related protein and the macrophages (Mφ) aggregation to the lamina propria. There were remarkable significant increase of stress-related hormones and pro-inflammatory factor interleukin (IL)-6 along with a decrease in the diversity of intestinal flora and an imbalance in the F/B ratio.

Conclusion

Our results reveal that stress accompanied with HTN could significantly disrupt the domino effect between intestinal flora and homeostasis.

Inhibition of NOX1 Mitigates Blood Pressure Increases in Elastin Insufficiency

Elastin (ELN) insufficiency leads to the cardiovascular hallmarks of the contiguous gene deletion disorder, Williams-Beuren syndrome, including hypertension and vascular stiffness. Previous studies showed that Williams-Beuren syndrome deletions, which extended to include the NCF1 gene, were associated with lower blood pressure (BP) and reduced vascular stiffness. NCF1 encodes for p47phox, the regulatory component of the NOX1 NADPH oxidase complex that generates reactive oxygen species (ROS) in the vascular wall. Dihydroethidium and 8-hydroxyguanosine staining of mouse aortas confirmed that Eln heterozygotes (Eln^+/- ) had greater ROS levels than the wild-types (Eln^+/+ ), a finding that was negated in vessels cultured without hemodynamic stressors. To analyze the Nox effect on ELN insufficiency, we used both genetic and chemical manipulations. Both Ncf1 haploinsufficiency (Ncf1^+/- ) and Nox1 insufficiency (Nox1^-/y ) decreased oxidative stress and systolic BP in Eln^+/- without modifying vascular structure. Chronic treatment with apocynin, a p47phox inhibitor, lowered systolic BP in Eln^+/- , but had no impact on Eln^+/+ controls. In vivo dosing with phenylephrine (PE) produced an augmented BP response in Eln^+/- relative to Eln^+/+ , and genetic modifications or drug-based interventions that lower Nox1 expression reduced the hypercontractile response to PE in Eln^+/- mice to Eln^+/+ levels. These results indicate that the mechanical and structural differences caused by ELN insufficiency leading to oscillatory flow can perpetuate oxidative stress conditions, which are linked to hypertension, and that by lowering the Nox1-mediated capacity for vascular ROS production, BP differences can be normalized.

Innate Immune Mechanisms of Arterial Hypertension and Autoimmune Disease

The immune system is indispensable in the development of vascular dysfunction and hypertension. The interplay between immune cells and the vasculature, kidneys, heart, and blood pressure regulating nuclei in the central nervous system results in a complex and closely interwoven relationship of the immune system with arterial hypertension. A better understanding of this interplay is necessary for optimized and individualized antihypertensive therapy. Our review article focuses on innate cells in hypertension and to what extent they impact on development and preservation of elevated blood pressure. Moreover, we address the association of hypertension with chronic autoimmune diseases. The latter are ideally suited to learn about immune-mediated mechanisms in cardiovascular disease leading to high blood pressure.

Trained Immunity and Reactivity of Macrophages and Endothelial Cells

Innate immune cells can develop exacerbated immunologic response and long-term inflammatory phenotype following brief exposure to endogenous or exogenous insults, which leads to an altered response towards a second challenge after the return to a nonactivated state. This phenomenon is known as trained immunity (TI). TI is not only important for host defense and vaccine response but also for chronic inflammations such as cardiovascular and metabolic diseases such as atherosclerosis. TI can occur in innate immune cells such as monocytes/macrophages, natural killer cells, endothelial cells (ECs), and nonimmune cells, such as fibroblast. In this brief review, we analyze the significance of TI in ECs, which are also considered as innate immune cells in addition to macrophages. TI can be induced by a variety of stimuli, including lipopolysaccharides, BCG (bacillus Calmette-Guerin), and oxLDL (oxidized low-density lipoprotein), which are defined as risk factors for cardiovascular and metabolic diseases. Furthermore, TI in ECs is functional for inflammation effectiveness and transition to chronic inflammation. Rewiring of cellular metabolism of the trained cells takes place during induction of TI, including increased glycolysis, glutaminolysis, increased accumulation of tricarboxylic acid cycle metabolites and acetyl-coenzyme A production, as well as increased mevalonate synthesis. Subsequently, this leads to epigenetic remodeling, resulting in important changes in chromatin architecture that enables increased gene transcription and enhanced proinflammatory immune response. However, TI pathways and inflammatory pathways are separated to ensure memory stays when inflammation undergoes resolution. Additionally, reactive oxygen species play context-dependent roles in TI. Therefore, TI plays significant roles in EC and macrophage pathology and chronic inflammation. However, further characterization of TI in ECs and macrophages would provide novel insights into cardiovascular disease pathogenesis and new therapeutic targets. Graphic Abstract: A graphic abstract is available for this article.

Vascular Inflammation and Cardiovascular Burden in Metastatic Breast Cancer Female Patients Receiving Hormonal Treatment and CDK 4/6 Inhibitors or Everolimus

Background: Chemotherapy regimens for breast cancer treatment can promote vascular dysfunction and lead to high cardiovascular risk. Purpose: To investigate the cardiovascular burden and vascular inflammation in metastatic breast cancer patients receiving CDK 4/6 inhibitors or everolimus in addition to standard hormonal treatment. Methods: 22 consecutive female patients with metastatic breast cancer were enrolled. Relative wall thickness (RWT) and left ventricle mass (LVM) measurements by transthoracic echocardiography were obtained followed by 24-h ambulatory blood pressure monitoring, and ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography imaging. Uptake of the radiotracer in the aortic wall was estimated as tissue-to-background ratio (TBR). Each patient was assessed for the aforementioned parameters before the initiation and after 6 months of treatment. Results: At follow up, patients assigned to CDK 4/6 treatment demonstrated increased 24-h systolic blood pressure (SBP) (p = 0.004), daytime SBP (p = 0.004) and night time SBP (p = 0.012) (Group effect). The 24-h mean arterial pressure measurements were also higher in CDK 4/6 population, in comparison to everolimus that displayed firm values (Group effect- p = 0.035, Interaction effect-p = 0.023). Additionally, 24 h diastolic blood pressure recordings in CDK 4/6 therapy were higher opposed to everolimus that remained consistent (Interaction effect- p = 0.010). In CDK 4/6 group, TBR aorta also increased significantly, whereas TBR values in everolimus remained stable (Interaction effect-p = 0.049). Both therapeutic regimens displayed statistically significant damaging effect to RWT and LVM. Conclusion: CDK 4/6 inhibitors and hormonal treatment can lead to increased vascular inflammation, and higher blood pressure compared to the combination of everolimus and hormonal treatment. Moreover, both treatment strategies promoted left ventricle remodeling.

DPP4 inhibition mitigates ANG II-mediated kidney immune activation and injury in male mice

Recent evidence suggests that dipeptidyl peptidase-4 (DPP4) inhibition with saxagliptin (Saxa) is renoprotective under comorbid conditions associated with activation of the renin-angiotensin-aldosterone system (RAAS), such as diabetes, obesity, and hypertension, which confer a high cardiovascular risk. Immune system activation is now recognized as a contributor to RAAS-mediated tissue injury, and, importantly, immunomodulatory effects of DPP4 have been reported. Accordingly, we examined the hypothesis that DPP4 inhibition with Saxa attenuates angiotensin II (ANG II)-induced kidney injury and albuminuria via attenuation of immune activation in the kidney. To this end, male mice were infused with either vehicle or ANG II (1,000 ng/kg/min, s.c.) for 3 wk and received either placebo or Saxa (10 mg/kg/day, p.o.) during the final 2 wk. ANG II infusion increased kidney, but not plasma, DPP4 activity in vivo as well as DPP4 activity in cultured proximal tubule cells. The latter was prevented by angiotensin receptor blockade with olmesartan. Further, ANG II induced hypertension and kidney injury characterized by mesangial expansion, mitochondrial damage, reduced brush border megalin expression, and albuminuria. Saxa inhibited DPP4 activity ∼50% in vivo and attenuated ANG II-mediated kidney injury, independent of blood pressure. Further mechanistic experiments revealed mitigation by Saxa of proinflammatory and profibrotic mediators activated by ANG II in the kidney, including CD8⁺ T cells, resident macrophages (CD11b^hiF4/80^loLy6C^-), and neutrophils. In addition, Saxa improved ANG II suppressed anti-inflammatory regulatory T cell and T helper 2 lymphocyte activity. Taken together, these results demonstrate, for the first time, blood pressure-independent involvement of renal DPP4 activation contributing to RAAS-dependent kidney injury and immune activation.NEW & NOTEWORTHY This work highlights the role of dipeptidyl peptidase-4 (DPP4) in promoting ANG II-mediated kidney inflammation and injury. Specifically, ANG II infusion in mice led to increases in blood pressure and kidney DPP4 activity, which then led to activation of CD8⁺ T cells, Ly6C^- macrophages, and neutrophils and suppression of anti-inflammatory T helper 2 lymphocytes and regulatory T cells. Collectively, this led to kidney injury, characterized by mesangial expansion, mitochondrial damage, and albuminuria, which were mitigated by DPP4 inhibition independent of blood pressure reduction.

Endothelial Dysfunction and Its Clinical Implications

Endothelial dysfunction (ED) plays a substantial role in the pathogenesis of atherosclerosis and some other vascular diseases. ED has been demonstrated in patients with hypercholesterolemia, diabetes, smoking, hypertension, and in patients with atherosclerotic disease. Besides classical risk factors, ED is affected by chronic inflammatory diseases and acute infections, particularly viral diseases. Causes of ED include oxidative stress, inflammation, and shear stress, which decrease the bioavailability of nitric oxide. Markers of ED have been sought, particularly circulating markers. Using these tests, it is possible to evaluate the response to harmful effects of risk factors and the effects of treatment on vessel wall function. Endothelial dysfunction is significantly and directly correlated with the occurrence of cardiac events and the risk of cardiac events increase as ED worsens. Because endothelial function plays a central role in atherogenesis it became a therapeutic target. Endothelial dysfunction is reversible and its improvement may be achieved by elimination of risk factors, inhibitors of endothelium-derived contracting factors (angiotensin-converting enzyme), smoking cessation, lipid-lowering drugs, diet, and physical exercise. By reversing ED, it is possible to restore vascular function.

Emerging Role of the Inflammasome and Pyroptosis in Hypertension

Inflammasomes are components of the innate immune response that have recently emerged as crucial controllers of tissue homeostasis. In particular, the nucleotide-binding domain, leucine-rich-containing (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is a complex platform involved in the activation of caspase-1 and the maturation of interleukin (IL)-1β and IL-18, which are mainly released via pyroptosis. Pyroptosis is a caspase-1-dependent type of cell death that is mediated by the cleavage of gasdermin D and the subsequent formation of structurally stable pores in the cell membrane. Through these pores formed by gasdermin proteins cytosolic contents are released into the extracellular space and act as damage-associated molecular patterns, which are pro-inflammatory signals. Inflammation is a main contributor to the development of hypertension and it also is known to stimulate fibrosis and end-organ damage. Patients with essential hypertension and animal models of hypertension exhibit elevated levels of circulating IL-1β. Downregulation of the expression of key components of the NLRP3 inflammasome delays the development of hypertension and pharmacological inhibition of this inflammasome leads to reduced blood pressure in animal models and humans. Although the relationship between pyroptosis and hypertension is not well established yet, pyroptosis has been associated with renal and cardiovascular diseases, instances where high blood pressure is a critical risk factor. In this review, we summarize the recent literature addressing the role of pyroptosis and the inflammasome in the development of hypertension and discuss the potential use of approaches targeting this pathway as future anti-hypertensive strategies.

Immunity and Hypertension

Hypertension is the primary cause of cardiovascular mortality. Despite multiple existing treatments, only half of those with the disease achieve adequate control. Therefore, understanding the mechanisms causing hypertension is essential for the development of novel therapies. Many studies demonstrate that immune cell infiltration of the vessel wall, kidney and central nervous system, as well as their counterparts of oxidative stress, the renal renin-angiotensin system (RAS) and sympathetic tone play a critical role in the development of hypertension. Genetically modified mice lacking components of innate and/or adaptive immunity confirm the importance of chronic inflammation in hypertension and its complications. Depletion of immune cells improves endothelial function, decreases oxidative stress, reduces vascular tone and prevents renal interstitial infiltrates, sodium retention and kidney damage. Moreover, the ablation of microglia or central nervous system perivascular macrophages reduces RAS-induced inflammation and prevents sympathetic nervous system activation and hypertension. Therefore, understanding immune cell functioning and their interactions with tissues that regulate hypertensive responses may be the future of novel antihypertensive therapies.

T cell-derived extracellular vesicles are elevated in essential HTN

Extracellular vesicles (EVs) are novel mediators of cell-to-cell communication and appear to mediate the pathogenesis of hypertension (HTN). However, the mechanisms underlying the involvement of EVs in HTN remain unclear. The adaptive and innate immune systems play an important role affecting the kidney and vasculature in animal models of HTN. Evolving evidence shows that immune cell-derived EVs can modulate the immune system in a paracrine fashion and therefore may mediate the effects of inflammation in the pathogenesis of HTN. Therefore, we aimed to understand if specific subtypes of leukocyte/immune cell-derived EVs are altered in essential HTN using an in vivo model of angiotensin II (ANG II)-induced HTN. After 4 wk of ANG II treatment, EVs were isolated from the blood and kidney. EV origin and counts were characterized with Imaging Flow Cytometry, antibody panels targeting platelets, endothelial cells, and leukocytes including B and T cells, monocytes, and neutrophils. Leukocyte-derived EVs (CD45+) were elevated in the circulation and kidney tissue in ANG II-induced HTN. Subgroup analysis depicted T cell-derived EVs (CD3+) to be significantly elevated in ANG II-induced HTN (3.50e+5 particles/mL) compared with control groups (9.16e+4 particles/mL, P = 0.0106). T cell-derived EVs also significantly correlated with systolic blood pressure levels (r2 = 0.898, P = 0.0012). In summary, leukocyte-derived EVs, and more specifically T cell-derived EVs (CD3+), are elevated in ANG II-induced HTN in the circulation and kidney tissue and correlate well with blood pressure severity. EVs from the circulation and kidney may be sensitive biomarkers for HTN and end-organ damage and may lead to new mechanistic insights in this silent disease.

Electroacupuncture Improves Blood Pressure in SHRs by Regulating the Immune Balance between Th17 and Treg

The present study investigated the effects of electroacupuncture on blood pressure in spontaneously hypertensive rats (SHRs) by regulating the immune balance of T helper 17 cells (Th17 cells) and regulatory T cells (Treg cells). This study investigated the role of electroacupuncture in the immune balance of SHRs using Western blot, flow cytometry, and ELISA techniques. Electroacupuncture significantly improved blood pressure, downregulated the expression of RORγt, and upregulated the expression of Foxp3, reduced the production of Th17 cells, promoted the production of Treg cells, reduced the secretion of IL-6 and IL-17, and increased the secretion of TGF-β1 and IL-10. These findings suggest that electroacupuncture therapy effectively improved the systolic blood pressure of SHRs, and its mechanism may be related to promotion of the immune balance between Th17 and Treg.

Systems Pharmacology-Based Strategy to Investigate Pharmacological Mechanisms of Radix Puerariae for Treatment of Hypertension

Hypertension is a clinical cardiovascular syndrome characterized by elevated systemic arterial pressure with or without multiple cardiovascular risk factors. Radix Pueraria (RP) has the effects of anti-myocardial ischemia, anti-arrhythmia, vasodilatation, blood pressure reduction, anti-inflammation, and attenuating insulin resistance. Although RP can be effective for the treatment of hypertension, its active compounds, drug targets, and exact molecular mechanism are still unclear. In this study, systems pharmacology was used to analyze the active compounds, drug target genes, and key pathways of RP in the treatment of hypertension. Thirteen active compounds and related information on RP were obtained from the TCMSP database, and 140 overlapping genes related to hypertension and drugs were obtained from the GeneCards and OMIM databases. A PPI network and a traditional Chinese medicine (TCM) comprehensive network (Drug-Compounds-Genes-Disease network) were constructed, and 2,246 GO terms and 157 pathways were obtained by GO enrichment analysis and KEGG pathway enrichment analysis. Some important active compounds and targets were evaluated by in vitro experiments. This study shows that RP probably acts by influencing the proliferation module, apoptosis module, inflammation module, and others when treating hypertension. This study provides novel insights for researchers to systematically explore the mechanism of action of TCM.

Neuroimmune crosstalk in the pathophysiology of hypertension

Hypertension is an important risk factor for cardiovascular morbidity and mortality and for events such as myocardial infarction, stroke, heart failure and chronic kidney disease and is a major determinant of disability-adjusted life-years. Despite the importance of hypertension, the pathogenesis of essential hypertension, which involves the complex interaction of several mechanisms, is still poorly understood. Evidence suggests that interplay between bone marrow, microglia and immune mediators underlies the development of arterial hypertension, in particular through mechanisms involving cytokines and peptides, such as neuropeptide Y, substance P, angiotensin II and angiotensin-(1-7). Chronic psychological stress also seems to have a role in increasing the risk of hypertension, probably through the activation of neuroimmune pathways. In this Review, we summarize the available data on the possible role of neuroimmune crosstalk in the origin and maintenance of arterial hypertension and discuss the implications of this crosstalk for recovery and rehabilitation after cardiac and cerebral injuries.

Mitochondrial Deacetylase Sirt3 Reduces Vascular Dysfunction and Hypertension While Sirt3 Depletion in Essential Hypertension Is Linked to Vascular Inflammation and Oxidative Stress

RATIONALE

Hypertension represents a major risk factor for stroke, myocardial infarction, and heart failure and affects 30% of the adult population. Mitochondrial dysfunction contributes to hypertension, but specific mechanisms are unclear. The mitochondrial deacetylase Sirt3 (Sirtuin 3) is critical in the regulation of metabolic and antioxidant functions which are associated with hypertension, and cardiovascular disease risk factors diminish Sirt3 level.

OBJECTIVE

We hypothesized that reduced Sirt3 expression contributes to vascular dysfunction in hypertension, but increased Sirt3 protects vascular function and decreases hypertension.

METHODS AND RESULTS

To test the therapeutic potential of targeting Sirt3 expression, we developed new transgenic mice with global Sirt3OX (Sirt3 overexpression), which protects from endothelial dysfunction, vascular oxidative stress, and hypertrophy and attenuates Ang II (angiotensin II) and deoxycorticosterone acetate-salt induced hypertension. Global Sirt3 depletion in Sirt3^-/- mice results in oxidative stress due to hyperacetylation of mitochondrial superoxide dismutase (SOD2), increases HIF1α (hypoxia-inducible factor-1), reduces endothelial cadherin, stimulates vascular hypertrophy, increases vascular permeability and vascular inflammation (p65, caspase 1, VCAM [vascular cell adhesion molecule-1], ICAM [intercellular adhesion molecule-1], and MCP1 [monocyte chemoattractant protein 1]), increases inflammatory cell infiltration in the kidney, reduces telomerase expression, and accelerates vascular senescence and age-dependent hypertension; conversely, increased Sirt3 expression in Sirt3OX mice prevents these deleterious effects. The clinical relevance of Sirt3 depletion was confirmed in arterioles from human mediastinal fat in patients with essential hypertension showing a 40% decrease in vascular Sirt3, coupled with Sirt3-dependent 3-fold increases in SOD2 acetylation, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activity, VCAM, ICAM, and MCP1 levels in hypertensive subjects compared with normotensive subjects.

CONCLUSIONS

We suggest that Sirt3 depletion in hypertension promotes endothelial dysfunction, vascular hypertrophy, vascular inflammation, and end-organ damage. Our data support a therapeutic potential of targeting Sirt3 expression in vascular dysfunction and hypertension.

Current and emerging avenues for Alzheimer's disease drug targets

Alzheimer's disease (AD), the most frequent cause of dementia, is escalating as a global epidemic, and so far, there is neither cure nor treatment to alter its progression. The most important feature of the disease is neuronal death and loss of cognitive functions, caused probably from several pathological processes in the brain. The main neuropathological features of AD are widely described as amyloid beta (Aβ) plaques and neurofibrillary tangles of the aggregated protein tau, which contribute to the disease. Nevertheless, AD brains suffer from a variety of alterations in function, such as energy metabolism, inflammation and synaptic activity. The latest decades have seen an explosion of genes and molecules that can be employed as targets aiming to improve brain physiology, which can result in preventive strategies for AD. Moreover, therapeutics using these targets can help AD brains to sustain function during the development of AD pathology. Here, we review broadly recent information for potential targets that can modify AD through diverse pharmacological and nonpharmacological approaches including gene therapy. We propose that AD could be tackled not only using combination therapies including Aβ and tau, but also considering insulin and cholesterol metabolism, vascular function, synaptic plasticity, epigenetics, neurovascular junction and blood-brain barrier targets that have been studied recently. We also make a case for the role of gut microbiota in AD. Our hope is to promote the continuing research of diverse targets affecting AD and promote diverse targeting as a near-future strategy.

MMP-12, Secreted by Pro-Inflammatory Macrophages, Targets Endoglin in Human Macrophages and Endothelial Cells

Upon inflammation, monocyte-derived macrophages (MΦ) infiltrate blood vessels to regulate several processes involved in vascular pathophysiology. However, little is known about the mediators involved. Macrophage polarization is crucial for a fast and efficient initial response (GM-MΦ) and a good resolution (M-MΦ) of the inflammatory process. The functional activity of polarized MΦ is exerted mainly through their secretome, which can target other cell types, including endothelial cells. Endoglin (CD105) is a cell surface receptor expressed by endothelial cells and MΦ that is markedly upregulated in inflammation and critically involved in angiogenesis. In addition, a soluble form of endoglin with anti-angiogenic activity has been described in inflammation-associated pathologies. The aim of this work was to identify components of the MΦ secretome involved in the shedding of soluble endoglin. We find that the GM-MΦ secretome contains metalloprotease 12 (MMP-12), a GM-MΦ specific marker that may account for the anti-angiogenic activity of the GM-MΦ secretome. Cell surface endoglin is present in both GM-MΦ and M-MΦ, but soluble endoglin is only detected in GM-MΦ culture supernatants. Moreover, MMP-12 is responsible for the shedding of soluble endoglin in vitro and in vivo by targeting membrane-bound endoglin in both MΦ and endothelial cells. These data demonstrate a direct correlation between GM-MΦ polarization, MMP-12, and soluble endoglin expression and function. By targeting endothelial cells, MMP-12 may represent a novel mediator involved in vascular homeostasis.

Arterial Hypertension and Interleukins: Potential Therapeutic Target or Future Diagnostic Marker?

Hypertension as a multifactorial pathology is one of the most important cardiovascular risk factors, affecting up to 30-40% of the general population. Complex immune responses are involved in the inflammatory mechanism of hypertension, with evidence pointing to increased inflammatory mediators even in prehypertensive patients. Increased vascular permeability, thrombogenesis, and fibrosis, effects that are associated with sustained hypertension, could be attributed to chronic inflammation. Chronic inflammation triggers endothelial dysfunction via increased production of ROS through proinflammatory cytokines. Increased serum level of proinflammatory cytokines such as IL-1β, IL-6, IL-8, IL-17, IL-23, TGFβ, and TNFα in hypertensive patients has been associated with either increased blood pressure values and/or end-organ damage. Moreover, some cytokines (i.e., IL-6) seem to determine a hypertensive response to angiotensin II, regardless of blood pressure values. Understanding hypertension as an inflammatory-based pathology gives way to new therapeutic targets. As such, conventional cardiovascular drugs (statins, calcium channels blockers, and ACEIs/ARBs) have shown additional anti-inflammatory effects that could be linked to their blood pressure lowering properties. Moreover, anti-inflammatory drugs (mycophenolate mofetil) have been shown to decrease blood pressure in hypertensive patients or prevent its development in normotensive individuals. Further research is needed to evaluate whether drugs targeting hypertensive-linked proinflammatory cytokines, such as monoclonal antibodies, could become a new therapeutic option in treating arterial hypertension.

Sodium in the microenvironment regulates immune responses and tissue homeostasis

During tissue inflammation, immune cells infiltrate the interstitial space of target organs, where they sense and adapt to local environmental stimuli. Such stimuli include not only pathogens but also local factors such as the levels of oxygenation, nutrients and electrolytes. An important electrolyte in this regard is sodium (Na+). Recent in vivo findings have shown a role of Na+ storage in the skin for electrolyte homeostasis. Thereby, Na+ intake may influence the activation status of the immune system through direct effects on T helper cell subsets and innate immune cells in tissues such as the skin and other target organs. Furthermore, high Na+ intake has been shown to alter the composition of the intestinal microbiota, with indirect effects on immune cells. The results suggest regulatory roles for Na+ in cardiovascular disease, inflammation, infection and autoimmunity.

Novel Role of T Cells and IL-6 (Interleukin-6) in Angiotensin II-Induced Microvascular Dysfunction

Hypertension is an established risk factor for subsequent cardiovascular diseases, with Ang II (angiotensin II) playing a major role in mediating thrombotic and inflammatory abnormalities. Although T cells and IL-6 (interleukin-6) play an important role in adaptive immune responses, little is known about their role(s) in the thromboinflammatory responses associated with Ang II. Here we show using intravital microscopy coupled with the light/dye injury model that Rag-1 deficient (Rag-1-/-) and IL-6 deficient (IL-6-/-) mice are afforded protection against Ang II-induced thrombosis. Blocking IL-6 receptors (using CD126 and gp130 antibodies) significantly diminished Ang II-mediated thrombosis and inflammatory cell recruitment in mice. Furthermore, the adoptive transfer of IL-6-/--derived T cells into Rag-1-/- mice failed to accelerate Ang II-induced thrombosis compared with Rag-1-/- mice reconstituted with wild-type-derived T cells, suggesting T cell IL-6 mediates the thrombotic abnormalities associated Ang II hypertension. Interestingly, adoptive transfer of WT T cells into Rag-1-/-/Ang II mice resulted in increased numbers of immature platelets, which constitutes a more active platelet population, that is, prothrombotic and proinflammatory. To translate our in vivo findings, we used clinical samples to demonstrate that IL-6 also predisposes platelets to an interaction with collagen receptors, thereby increasing the propensity for platelets to aggregate and cause thrombosis. In summary, we provide compelling evidence for the involvement of IL-6, IL-6R, and T-cell-dependent IL-6 signaling in Ang II-induced thromboinflammation, which may provide new therapeutic possibilities for drug discovery programs for the management of hypertension.

Some Macrophages Are Softies

Adequate maintenance of the arterial extracellular matrix is essential for steady-state vascular functions. In this issue of Immunity, Lim et al. (2018) describe that aortic LYVE-1⁺ macrophages regulate steady-state arterial matrix content by interacting with smooth muscle cells and collagen.

Tobacco smoking induces cardiovascular mitochondrial oxidative stress, promotes endothelial dysfunction, and enhances hypertension

Tobacco smoking is a major risk factor for cardiovascular disease and hypertension. It is associated with the oxidative stress and induces metabolic reprogramming, altering mitochondrial function. We hypothesized that cigarette smoke induces cardiovascular mitochondrial oxidative stress, which contributes to endothelial dysfunction and hypertension. To test this hypothesis, we studied whether the scavenging of mitochondrial H₂O₂ in transgenic mice expressing mitochondria-targeted catalase (mCAT) attenuates the development of cigarette smoke/angiotensin II-induced mitochondrial oxidative stress and hypertension compared with wild-type mice. Two weeks of exposure of wild-type mice with cigarette smoke increased systolic blood pressure by 17 mmHg, which was similar to the effect of a subpresssor dose of angiotensin II (0.2 mg·kg^-1·day^-1), leading to a moderate increase to the prehypertensive level. Cigarette smoke exposure and a low dose of angiotensin II cooperatively induced severe hypertension in wild-type mice, but the scavenging of mitochondrial H₂O₂ in mCAT mice completely prevented the development of hypertension. Cigarette smoke and angiotensin II cooperatively induced oxidation of cardiolipin (a specific biomarker of mitochondrial oxidative stress) in wild-type mice, which was abolished in mCAT mice. Cigarette smoke and angiotensin II impaired endothelium-dependent relaxation and induced superoxide overproduction, which was diminished in mCAT mice. To mimic the tobacco smoke exposure, we used cigarette smoke condensate, which induced mitochondrial superoxide overproduction and reduced endothelial nitric oxide (a hallmark of endothelial dysfunction in hypertension). Western blot experiments indicated that tobacco smoke and angiotensin II reduce the mitochondrial deacetylase sirtuin-3 level and cause hyperacetylation of a key mitochondrial antioxidant, SOD2, which promotes mitochondrial oxidative stress. NEW & NOTEWORTHY This work demonstrates tobacco smoking-induced mitochondrial oxidative stress, which contributes to endothelial dysfunction and development of hypertension. We suggest that the targeting of mitochondrial oxidative stress can be beneficial for treatment of pathological conditions associated with tobacco smoking, such as endothelial dysfunction, hypertension, and cardiovascular diseases.

Protective effect of Xin-Ji-Er-Kang on cardiovascular remodeling in high salt-induced hypertensive mice

The aim of the present study was to investigate the effects of Xin-Ji-Er-Kang (XJEK) on high salt-induced hypertensive mice. Mice with high-salt diet-induced hypertension were divided into four groups: Control (standard diet alone for 8 weeks), model (diet containing 8% NaCl for 8 weeks and intragastric administration of distilled water for the last 4 weeks), XJEK + high-salt-treated (diet containing 8% NaCl for 8 weeks and intragastric administration of XJEK for the last 4 weeks) and irbesartan + high-salt-treated (diet containing 8% NaCl for 8 weeks with intragastric administration of irbesartan for the last 4 weeks). The hemodynamic index and cardiac pathological changes in the hypertensive mice were then examined. An aortic ring apparatus was used to detect acetylcholine-dependent endothelium relaxation function. Colorimetric analysis was applied to determine serum nitric oxide (NO), superoxide dismutase activity and malondialdehyde content; ELISA was employed to measure brain natriuretic peptide, serum angiotensin II (Ang II), endothelin-1 content and aldosterone; and immunohistochemistry was used to detect the expression of endothelial nitric oxide synthase (eNOS), interleukin (IL)-1β, IL-10 and tumor necrosis factor (TNF)-α in cardiac tissues. XJEK improved the heart systolic and diastolic function, ameliorated hemodynamic parameters and cardiovascular remodeling indices, blunted the cardiac pathological changes and improved endothelial dysfunction (ED) via boosting eNOS activity, promoting NO bioavailability and decreasing serum Ang II content. Furthermore, treatment with XJEK inhibited the increase of IL-1β and TNF-α expression and the decrease of IL-10 expression in cardiac tissues, and ameliorated oxidative stress status. Therefore, XJEK exerted protective effects against high salt-induced hypertension and cardiovascular remodeling in mice via improving ED, restoring pro- and anti-inflammatory factor balance and decreasing oxidative stress.

Skin Sodium and Hypertension: a Paradigm Shift?

Purpose of Review

Dietary sodium is an important trigger for hypertension and humans show a heterogeneous blood pressure response to salt intake. The precise mechanisms for this have not been fully explained although renal sodium handling has traditionally been considered to play a central role.

Recent Findings

Animal studies have shown that dietary salt loading results in non-osmotic sodium accumulation via glycosaminoglycans and lymphangiogenesis in skin mediated by vascular endothelial growth factor-C, both processes attenuating the rise in BP. Studies in humans have shown that skin could be a buffer for sodium and that skin sodium could be a marker of hypertension and salt sensitivity.

Summary

Skin sodium storage could represent an additional system influencing the response to salt load and blood pressure in humans.

Clinical pertinence of neutrophil-to- lymphocyte ratio among hypertensives with different grades and duration of hypertension - an insight

Over the recent years, the pathophysiology of the inflammatory component in hypertension has been a challenge, because this inflammatory response is mainly contributed by an increased oxidative stress with the release of inflammatory mediators. Identification of a simple and early inflammatory marker such as the neutrophil-to-lymphocyte ratio (NLR) is the need of the hour. This study correlates the same specifically taking into account the duration and the grades of hypertension.

OBJECTIVE

The response of the NLR among the hypertensives and its correlation with duration and stages of hypertension.

METHOD

Totally, 80 subjects and 40 controls of age between 20 and 60 years and both genders were included. Three recordings of blood pressure were measured with a standard mercury sphygmomanometer. The differential leukocyte count was estimated with an automated Beckman Coulter.

OBJECTIVE

Variations in the neutrophil and lymphocyte counts were significant among the hypertensives with a p-value < 0.001. The NLR was also significantly altered among the hypertensives with a p-value = 0.001. The NLR showed a rise in value among the normotensives, prehypertensives, and stage 1 of systolic hypertension, though not statistically significant. An increase in the NLR was observed in hypertensives with duration of 1-2 years.

CONCLUSION

Our study gives a new insight with a rise in NLR in early years and even among prehypertensives and stage 1 systolic hypertension under strict criterion. This could be utilized as an early predictive tool, relating the inflammatory process and hypertension which on further intervention could slow the progression of the disease process.

ABBREVIATIONS

NLR: Neutrophil-to-lymphocyte ratio; BP: Blood pressure.

Increased expression and functionality of the gap junction in peripheral blood lymphocytes is associated with hypertension-mediated inflammation in spontaneously hypertensive rats

BACKGROUND

Imbalances in circulating T lymphocytes play critical roles in the pathogenesis of hypertension-mediated inflammation. Connexins (Cxs) in immune cells are involved in the maintenance of homeostasis of T lymphocytes. However, the association between Cxs in peripheral blood T lymphocytes and hypertension-mediated inflammation remains unknown. This study was designed to investigate the role of Cxs in T lymphocytes in hypertension-mediated inflammation in spontaneously hypertensive rats (SHRs).

METHODS

The systolic blood pressure (SBP) in Wistar-Kyoto (WKY) rats and SHRs was monitored using the tail-cuff method. The serum cytokine level was determined using ELISA. The proportions of different T-lymphocyte subtypes in the peripheral blood, the expressions of Cx40/Cx43 in the T-cell subtypes, and the gap junctional intracellular communication (GJIC) of peripheral blood lymphocytes were measured using flow cytometry (FC). The accumulations of Cx40/Cx43 at the plasma membrane and/or in the cytoplasm were determined using immunofluorescence staining. The in vitro mRNA levels of cytokines and GJIC in the peripheral blood lymphocytes were respectively examined using real-time PCR and FC after treatment with Gap27 and/or concanavalin A (Con A).

RESULTS

The percentage of CD4+ T cells and the CD4+/CD8+ ratio were high, and the accumulation or expressions of Cx40/Cx43 in the peripheral blood lymphocytes in SHRs were higher than in those of WKY rats. The percentage of CD8+ and CD4+CD25+ T cells was lower in SHRs. The serum levels of IL-2, IL-4 and IL-6 from SHRs were higher than those from WKY rats, and the serum levels of IL-2 and IL-6 positively correlated with the expression of Cx40/Cx43 in the peripheral blood T lymphocytes from SHRs. The peripheral blood lymphocytes of SHRs exhibited enhanced GJIC. Cx43-based channel inhibition, which was mediated by Gap27, remarkably reduced GJIC in lymphocytes, and suppressed IL-2 and IL-6 mRNA expressions in Con A stimulated peripheral blood lymphocytes.

CONCLUSIONS

Our data suggest that Cxs may be involved in the regulation of T-lymphocyte homeostasis and the production of cytokines. A clear association was found between alterations in Cxs expression or in Cx43-based GJIC and hypertension-mediated inflammation.

Renal Protective Effects of N-Acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) in Obese Rats on a High-Salt Diet

BACKGROUND

Obesity is a public health problem, associated with salt sensitive hypertension, kidney inflammation, and fibrosis. N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a tetra peptide with anti-inflammatory and anti-fibrotic properties. However, its effect on preventing kidney damage in obesity is unknown. We hypothesized that Zucker obese (ZO) rats on a high-salt (HS) diet develop renal damage, inflammation, fibrosis, and this is prevented with Ac-SDKP treatment.

METHODS

Zucker lean (ZL) and ZO rats (8 weeks old) were treated with Ac-SDKP (1.6 mg/kg/day) while maintained on either a normal-salt (NS; 0.4%) or HS (4%) diet for 8 weeks. Systolic blood pressure (SBP), albuminuria, renal inflammation, and fibrosis were evaluated.

RESULTS

HS diet increased macrophage infiltration in the kidneys of both ZL and ZO rats but was significantly higher in ZO rats receiving the HS diet (ZL + NS, 13.9 ± 1.3 vs. ZL + HS, 19.14 ± 1.5 and ZO + NS, 25.5 ± 1.4 vs. ZO + HS, 87.8 ± 10.8 cells/mm2; P < 0.05). Ac-SDKP prevented macrophage infiltration in ZO rats (ZO + HS + Ac-SDKP, 32.18 ± 2.4 cells/mm2; P < 0.05). Similarly, glomerulosclerosis, cortical, and medullary interstitial fibrosis were increased in ZO rats fed the HS diet, and Ac-SDKP attenuated these alterations (P < 0.05). SBP was increased in ZO rats fed the HS diet (ZO + NS, 121.3 ± 8.9 vs. ZO + HS, 164 ± 6.9 mm Hg; P < 0.05), and it was significantly decreased with Ac-SDKP treatment (ZO + HS + Ac-SDKP, 144.05 ± 14.1 mm Hg; P = 0.004). Albuminuria was higher in ZO rats than in ZL rats; however, neither HS nor Ac-SDKP treatment affected it.

CONCLUSIONS

Ac-SDKP treatment in ZO rats fed a HS diet prevented renal damage by reducing inflammation, fibrosis, and SBP.

Alteration in Brain Functional and Effective Connectivity in Subjects With Hypertension

To reveal the physiological mechanism of the cognitive decline in subjects with hypertension, the functional connectivity (FC) was assessed by using the wavelet phase coherence (WPCO), and effective connectivity (EC) was assessed by using the coupling strength (CS) of near-infrared spectroscopy (NIRS) signals. NIRS signals were continuously recorded from the prefrontal cortex, sensorimotor cortex, and occipital lobes of 13 hypertensive patients (hypertension group, 70 ± 6.5 years old) and 16 elderly healthy subjects (control group, 71 ± 5.5 years old) in resting and standing periods. WPCO and CS were calculated in four frequency intervals: I, 0.6–2; II, 0.145–0.6; III, 0.052–0.145; and IV, 0.021–0.052 Hz. CS quantifies coupling amplitude. In comparison with the control group, the hypertension group showed significantly decreased (p < 0.05) WPCO and CS in intervals III and IV and in the resting and standing states. WPCO and CS were significantly decreased in the resting state compared with those in the standing state in the hypertension group (p < 0.05). Decreased WPCO and CS indicated a reduced network interaction, suggesting disturbed neurovascular coupling in subjects with hypertension. Compared with the control group, the hypertension group showed significantly lower Mini-Mental State Examination (MMSE) (p = 0.028) and Montreal Cognitive Assessment (MoCA) scores (p = 0.011). In the hypertension group, correlation analysis showed that WPCO and CS were significantly positively correlated with MMSE and MoCA scores, respectively. These findings may provide evidence of impaired cognitive function in hypertension and can enhance the understanding on neurovascular coupling.

The role of dipeptidylpeptidase-4 inhibitors in management of cardiovascular disease in diabetes; focus on linagliptin

Multiple population based analyses have demonstrated a high incidence of cardiovascular disease (CVD) and cardiovascular (CV) mortality in subjects with T2DM that reduces life expectancy by as much as 15 years. Importantly, the CV system is particularly sensitive to the metabolic and immune derangements present in obese pre-diabetic and diabetic individuals; consequently, CV dysfunction is often the initial CV derangement to occur and promotes the progression to end organ/tissue damage in T2DM. Specifically, diabetic CVD can manifest as microvascular complications, such as nephropathy, retinopathy, and neuropathy, as well as, macrovascular impairments, including ischemic heart disease, peripheral vascular disease, and cerebrovascular disease. Despite some progress in prevention and treatment of CVD, mainly via blood pressure and dyslipidemia control strategies, the impact of metabolic disease on CV outcomes is still a major challenge and persists in proportion to the epidemics of obesity and diabetes. There is abundant pre-clinical and clinical evidence implicating the DPP-4-incretin axis in CVD. In this regard, linagliptin is a unique DPP-4 inhibitor with both CV and renal safety profiles. Moreover, it exerts beneficial CV effects beyond glycemic control and beyond class effects. Linagliptin is protective for both macrovascular and microvascular complications of diabetes in preclinical models, as well as clinical models. Given the role of endothelial-immune cell interactions as one of the key events in the initiation and progression of CVD, linagliptin modulates these cell–cell interactions by affecting two important pathways involving stimulation of NO signaling and potent inhibition of a key immunoregulatory molecule.

Thymosin β4 Deficiency Exacerbates Renal and Cardiac Injury in Angiotensin-II-Induced Hypertension

Thymosin β4 (Tβ4), a ubiquitous peptide, regulates several cellular processes that include cell morphology, wound healing, and inflammatory response. Administration of exogenous Tβ4 is protective in diabetic nephropathy and in a unilateral ureteral obstruction model. However, the role of endogenous Tβ4 in health and disease conditions remains unclear. To elucidate the pathophysiological role of endogenous Tβ4 in hypertension, we examined angiotensin-II (Ang-II)-induced renal and cardiac damage in Tβ4 knockout (Tβ4 KO) mice. Tβ4 KO and wild-type C57BL/6 mice were infused continuously for 6 weeks with either vehicle or Ang-II (980 ng/kg per minute). At baseline, Tβ4 deficiency did not affect renal and cardiac function. Systolic blood pressure in the Ang-II group was similar in wild-type and Tβ4 KO mice (wild-type Ang-II, 179.25±10.11 mm Hg; Tβ4 KO Ang-II, 169.81±6.54 mm Hg). Despite the similar systolic blood pressure after Ang-II infusion, Tβ4-deficient mice had dramatically increased albuminuria and decreased nephrin expression in the kidney (P<0.005). In the heart of Tβ4 KO mice, Ang-II reduced ejection fraction and shortening fraction (ejection fraction: wild-type Ang-II 77.95%±1.03%; Tβ4 KO Ang-II 62.58%±3.25%; P<0.005), which was accompanied by cardiac hypertrophy and left ventricular dilatation. In addition, renal and cardiac infiltration of CD68 macrophages, intercellular adhesion molecule-1, and total collagen content were increased after Ang-II infusion in Tβ4 KO mice (P<0.005). Overall, our data indicate that endogenous Tβ4 is crucial in preventing tissue injury from Ang-II-induced hypertension. This study gives new insights into the protective role of endogenous Tβ4 in hypertensive end-organ damage.