A novel role for myeloid endothelin-B receptors in hypertension

Dual ETA-ETB receptor antagonism improves metabolic syndrome-induced heart failure with preserved ejection fraction

BACKGROUND

Metabolic syndrome (MetS) is a multifaceted disease associated with heart failure (HF), which affects the vascular system. The endothelin (ET) system is a key player in MetS and HF; therefore, targets for ET receptors are of therapeutic interest.

OBJECTIVES

This study sought to evaluate the effects of macitentan, a dual endothelin receptor antagonist (ERA), in a rat model of MetS-induced heart failure with preserved ejection fraction (HFpEF).

METHODS

We assessed in 12-week-old Zucker fa/fa rats the effects of macitentan (10 mg/kg/day as a food additive for short-term/7- or long-term/90-day treatment) on right ventricular (RV) and left ventricular (LV) function/remodelling (MRI), RV and LV haemodynamics (catheterization) and RV and LV coronary function (myograph).

RESULTS

After 7- and 90-days, untreated Zucker fa/fa rats presented isolated LV diastolic dysfunction (illustrated by elevated LV end-diastolic pressure [EDP] and LV end-diastolic pressure-volume relationship [EDPVR] without changes in LV EDPVR). This was associated with increased collagen deposition and impaired endothelium-dependent coronary artery relaxation. Macitentan 7- and 90-day treatment significantly decreased blood pressure and prevented LV, RV and coronary dysfunctions and long-term treatment reduced LV collagen density. Moreover, 7- and 90-day macitentan treatment significantly reduced cardiac inflammation and reactive oxygen species (ROS) production.

CONCLUSIONS

Dual ERA macitentan improved both LV and RV diastolic dysfunction. This was associated with improved coronary vasodilation, diminished cardiac oxidative stress and improved blood composition. These results suggest that antagonizing the ET system with macitentan is a promising approach to treat HFpEF and its complications.

Mendelian randomization evidence for lung function mediates the association between childhood allergies (age <16 years) and essential hypertension

Objective

This study aimed to investigate the influence of lung function on the relationship between allergies and hypertension, thereby elucidating significant potential mechanisms from a genetic standpoint. We investigated the causal relationship between childhood allergies (age <16 years) and essential hypertension and identified and quantified the role of lung function (forced vital capacity [FVC] and forced expiratory volume in the first second/forced vital capacity [FEV1/FVC]) as potential mediators.

Methods

Using data from a genome-wide association study and the Fenn Genn consortium, a two-sample Mendelian randomization (MR) analysis of genetically predicted childhood allergies (7128 cases and 211,703 controls) and essential hypertension (116,714 cases and 1,032,659 controls) was performed. Furthermore, we used two-step MR to quantify the effect of lung function-mediated childhood allergies on essential hypertension. The FVC and FEV1/FV sample size was 371,898.

Results

Childhood allergies were associated with increased odds of developing essential hypertension (odds ratio [OR] = 1.0900, 95% confidence interval [CI] =   1.0034-1.1842, P = 0.0414). No strong evidence that genetically predicted essential hypertension affected childhood allergy risk was identified (OR = 1.0631, 95% CI = 0.9829-1.1498, P = 0.1264). The proportion of genetically predicted childhood allergies mediated only by FVC was 5.67% (95% CI, 5.13%-5.73%).

Conclusion

A causal relationship between childhood allergies and essential hypertension was identified, with a proportion of the effect mediated by FVC. Therefore, implementing early interventions in children with allergies is imperative to mitigate the long-term risk of developing hypertension. Further research is required to identify additional risk factors as potential mediators.

Mechanisms of lung endothelial cell injury and survival in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive, chronic, and incurable inflammatory pulmonary vascular disease characterized by significant sex bias and largely unexplored microbial-associated molecular mechanisms that may influence its development and sex prevalence across various subgroups. PAH can be subclassified as idiopathic, heritable, or associated with conditions such as connective tissue diseases, congenital heart defects, liver disease, infections, and chronic exposure to drugs or toxins. During PAH progression, lung vascular endothelial cells (ECs) undergo dramatic morphofunctional transformations in response to acute and chronic inflammation. These transformations include the appearance and expansion of abnormal vascular cell phenotypes such as those derived from apoptosis-resistant cell growth and endothelial-to-mesenchymal transition (EndoMT). Compelling evidence indicates that these endothelial phenotypes seem to be triggered by chronic lung vascular injury and dysfunction, often characterized by reduced secretion of vasoactive molecules like nitric oxide (NO) and exacerbated response to vasoconstrictors such as Endothelin-1 (ET-1), both long-term known contributors of PAH pathogenesis. This review sheds light on the mechanisms of EC dysfunction, apoptosis, and EndoMT in PAH, aiming to unravel the intricate interactions between ECs, pathogens, and other cell types that drive the onset and progression of this devastating disease. Ultimately, we hope to provide an overview of the complex functions of lung vascular ECs in PAH, inspiring novel therapeutic strategies that target these dysfunctional cells to improve the treatment landscape for PAH, particularly in the face of current and emerging global pathogenic threats.

The Transcriptional Landscape of Pericytes in Acute Ischemic Stroke

The current treatment options for ischemic stroke aim to achieve reperfusion but are time critical. Novel therapeutic approaches that can be given beyond the limited time window of 3-4.5 h are still an unmet need to be addressed to improve stroke outcomes. The lack of oxygen and glucose in the area of ischemic injury initiates a pathological cascade leading to blood-brain barrier (BBB) breakdown, inflammation, and neuronal cell death, a process that may be intercepted to limit stroke progression. Pericytes located at the blood/brain interface are one of the first responders to hypoxia in stroke and therefore a potential target cell for early stroke interventions. Using single-cell RNA sequencing in a mouse model of permanent middle cerebral artery occlusion, we investigated the temporal differences in transcriptomic signatures in pericytes at 1, 12, and 24 h after stroke. Our results reveal a stroke-specific subcluster of pericytes that is present at 12 and 24 h and characterized by the upregulation of genes mainly related to cytokine signaling and immune response. This study identifies temporal transcriptional changes in the acute phase of ischemic stroke that reflect the early response of pericytes to the ischemic insult and its secondary consequences and may constitute potential future therapeutic targets.

Salivary microbial shifting in hypertensive patients with chronic periodontitis after scaling and root surface debridement

OBJECTIVES

This study aimed to evaluate the impact of scaling and root surface debridement (SRP) on salivary bacterial counts and systolic and diastolic blood pressure in hypertensive patients with chronic periodontitis, with a focus on clinical significance.

METHODS

An observational trial included 24 chronic periodontitis patients, eleven of them were hypertensive patients. Non-surgical periodontal treatment was administered to all patients, with clinical parameters including gingival index (GI), plaque index (PI), and probing pocket depth (PPD) recorded. Saliva samples were collected before and after SRP to quantify total bacterial counts and specific bacterial counts.

RESULTS

Two months following SRP, PI and PPD in every subject under study demonstrated good responses. In hypertension patients, the salivary bacterial count was significantly higher following SRP (P = 0.0221). The incidence of Porphyromonas gingivalis in hypertension patients significantly decreased after treatment (P = 0.0386). Despite this, there was no discernible decrease in blood pressure following treatment.

CONCLUSIONS

SRP alone was ineffective in reducing overall bacterial counts, but P. gingivalis levels responded favorably. Regular periodontal assessment is crucial for hypertensive individuals to mitigate cardiovascular risk.

CLINICAL SIGNIFICANCE

Periodontal therapy in hypertensive patients may improve oral health but might not significantly impact blood pressure. Regular periodontal evaluation is essential for managing cardiovascular risk in hypertension.

Immune and inflammatory mechanisms in hypertension

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

Salt Sensitivity: Causes, Consequences, and Recent Advances

Salt (sodium chloride) is an essential nutrient required to maintain physiological functions. However, for most people, daily salt intake far exceeds their physiological need and is habitually greater than recommended upper thresholds. Excess salt intake leads to elevation in blood pressure which drives cardiovascular morbidity and mortality. Indeed, excessive salt intake is estimated to be responsible for ≈5 million deaths per year globally. For approximately one-third of otherwise healthy individuals (and >50% of those with hypertension), the effect of salt intake on blood pressure elevation is exaggerated; such people are categorized as salt sensitive and salt sensitivity of blood pressure is considered an independent risk factor for cardiovascular disease and death. The prevalence of salt sensitivity is higher in women than in men and, in both, increases with age. This narrative review considers the foundational concepts of salt sensitivity and the underlying effector systems that cause salt sensitivity. We also consider recent updates in preclinical and clinical research that are revealing new modifying factors that determine the blood pressure response to high salt intake.

Evaluation of the Relationship between Sublingual Varices and Hypertension

Objectives: Sublingual varices are characterized by abnormally dilated veins. Some systemic conditions such as cardiovascular disease have been suggested to be associated with sublingual varices. Due to the convenience in examining the sublingual area, the present study aimed to assess the relationship between sublingual varices and hypertension. Materials and Methods: In this descriptive-analytic study, 500 patients were categorized into two groups: those with sublingual varices and those without. Two oral medicine specialists assessed the lesions, and the blood pressure of all patients was measured while they were in a relaxed sitting position. Age and gender data were recorded for all participants. Statistical analysis included t-test, chi-square, and logistic regression, with significance set at P<0.05. Results: The frequency of sublingual varices was 21.8%. Mean systolic blood pressure was 139.68±19.01mmHg in patients with sublingual varices and 118.09±13.78mmHg in patients without the lesions (P=0.561). Mean diastolic blood pressure was 100.45±17.81mmHg and 80.31±12.08mmHg in patients with and without sublingual varices, respectively (P<0.001). Smoking was significantly more prevalent among patients who had the lesions (P<0.05). Gender (P=0.686) and age (P=0.875) showed no significant relationship with sublingual varices, while smoking and blood pressure levels were significantly associated with these varices (P<0.001). Conclusion: It is advisable to monitor and manage blood pressure in patients with sublingual varices who may not be aware of their blood pressure status. Our results showed that smoking could be one of the predictive factors for sublingual varices.

Effects of potassium channel knockdown on peripheral blood T lymphocytes and NFAT signaling pathway in Xinjiang Kazak patients with hypertension

BACKGROUD AND AIM

T lymphocytes are involved in the occurrence and development of essential hypertension, and potassium channels are thought to be critical for lymphocyte activation. This study is to examine the roles of the voltage-gated potassium channels (Kv1.3) and calcium-activated potassium channels (KCa3.1) in peripheral blood T lymphocytes in Kazakh hypertensive patients of Xinjiang, China, mainly focusing on the effects of these channels on nuclear factor of activated T cells (NFAT) and inflammatory cytokines of T lymphocytes.

METHOD

Kv1.3 and KCa3.1 gene silencing were performed in cultured T lymphocytes from Kazakh patients with severe hypertension. T cell proliferation after gene silencing was measured using CCK-8. The mRNA and protein expression levels were measured using RT-qPCR and Western blot analysis, respectively. Nuclear translocation of NFAT was observed using laser confocal fluorescence microscopy. Inflammatory cytokine levels were detected with ELISA.

RESULTS

Compared with control group, gene silencing of Kv1.3 and KCa3.1 respectively inhibited the proliferation of T cells. Moreover, compared with the control group, the mRNA expression levels of NFAT, IL-6 and IFN-γ were significantly decreased after gene silencing. Furthermore, the NFAT protein expression level was significantly down-regulated. In addition, the levels of IFN-γ and IL-6 in the cell culture supernatant were significantly decreased.

CONCLUSION

Both Kv1.3 and KCa3.1 potassium channels activated T lymphocytes and enhanced the cytokine secretion possibly through CaN/NFAT signaling pathway, which may in turn induce micro-inflammatory responses and trigger the occurrence and progression of hypertension.

The Effect of Non-Surgical Periodontal Treatment on Patients with Combined Refractory Arterial Hypertension and Stage III, Grade B Periodontitis: A Preliminary Prospective Clinical Study

We sought to evaluate the effects of non-surgical periodontal treatment (NSPT) on periodontal clinical parameters, systemic blood pressure (BP), and plasma levels of systemic inflammation markers in patients with combined refractory arterial hypertension (RAH) and stage III grade B periodontitis. Twenty-seven participants with RAH and periodontitis received NSPT. The analyzed clinical parameters were probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), and plaque index (PI). An assessment was performed for systemic BP, complete blood count, coagulogram, creatinine measurement, C-reactive protein (CRP), glycated hemoglobin, cholesterol, glutamic oxaloacetic transaminase, glutamate pyruvic transaminase, waist-hip ratio, and body mass index. In the follow-up period, twenty-two patients were evaluated at baseline and after 90 and 180 days. The data were submitted for statistical analysis (α = 0.05%). As expected, the clinical results showed a significant improvement in the percentages of PI, BOP, PD, and CAL, which were statistically significant at 90 and 180 days (p < 0.0001). Importantly, NSPT significantly reduced the blood level of CRP (p < 0.02). However, no significant reduction in BP parameters was noted in the evaluated follow-up periods. NSPT, despite the benefits in periodontal clinical parameters, reduced the plasma level of CRP but not the BP in patients with combined RAH and periodontitis.

Association between periodontitis and hypertension: cross-sectional survey from the Fourth National Oral Health Survey of China (2015-2016)

OBJECTIVES

To evaluate the association between periodontitis severity and hypertension based on Chinese epidemiological data.

DESIGN

This cross-sectional survey enrolled adults from the Fourth National Oral Health Survey of China (2015-2016).

SETTING

The data were obtained from the Fourth National Oral Health Survey of China (2015-2016).

PARTICIPANTS

The study included individuals aged 35-44 years (n=4409), 55-64 years (n=4568) and 65-74 years (n=4218).

PRIMARY AND SECONDARY OUTCOME MEASURES

Periodontal status, defined on the basis of the 2017 classification scheme, and periodontal parameters (eg, bleeding on probing (BOP)) were compared between individuals with hypertension and individuals with normotension. Smoothed scatterplots were constructed to demonstrate the associations of periodontal parameters and periodontal status with hypertension.

RESULTS

Severe periodontitis (stages III and IV) was present in 41.4% of individuals with hypertension and 28.0% of individuals with normotension, respectively (p<0.001). The prevalence of severe periodontitis was higher in individuals with hypertension than that in individuals with normotension among participants aged 35-44 years (18.0% vs 10.1%, p<0.001) and 55-64 years (40.2% vs 36.7%, p=0.035), but not in participants aged 65-74 years (46.4% vs 45.1%, p=0.429). Therefore, the difference in periodontal status between individuals with hypertension and individuals with normotension decreased with age. There were higher prevalences of BOP, probing depth (PD) ≥4 mm and PD ≥6 mm in individuals with hypertension than in individuals with normotension (52.1% vs 49.2%, 19.6% vs 14.7% and 1.8% vs 1.1%, respectively). Periodontitis severity and the proportion of teeth with PD ≥4 or ≥6 mm were positively associated with hypertension.

CONCLUSION

Periodontitis is associated with hypertension in Chinese adults. Hypertension prevalence increased with periodontitis severity, particularly among young participants. Accordingly, it is necessary to improve the education, awareness of periodontal treatment and preventive management among individuals at risk of hypertension, particularly in the younger population.

Endothelin blockade prevents the long-term cardiovascular and renal sequelae of acute kidney injury in mice

Acute kidney injury (AKI) is common and associated with increased risks of cardiovascular and chronic kidney disease. Causative molecular/physiological pathways are poorly defined. There are no therapies to improve long-term outcomes. An activated endothelin system promotes cardiovascular and kidney disease progression. We hypothesized a causal role for this in the transition of AKI to chronic disease. Plasma endothelin-1 was threefold higher; urine endothelin-1 was twofold higher; and kidney preproendothelin-1, endothelin-A, and endothelin-B receptor message up-regulated in patients with AKI. To show causality, AKI was induced in mice by prolonged ischemia with a 4-week follow-up. Ischemic injury resulted in hypertension, endothelium-dependent and endothelium-independent macrovascular and microvascular dysfunction, and an increase in circulating inflammatory Ly6C^high monocytes. In the kidney, we observed fibrosis, microvascular rarefaction, and inflammation. Administration of endothelin-A antagonist, but not dual endothelin-A/B antagonist, normalized blood pressure, improved macrovascular and microvascular function, and prevented the transition of AKI to CKD. Endothelin-A blockade reduced circulating and renal proinflammatory Ly6C^high monocytes and B cells, and promoted recruitment of anti-inflammatory Ly6C^low monocytes to the kidney. Blood pressure reduction alone provided no benefits; blood pressure reduction alongside blockade of the endothelin system was as effective as endothelin-A antagonism in mitigating the long-term sequelae of AKI in mice. Our studies suggest up-regulation of the endothelin system in patients with AKI and show in mice that existing drugs that block the endothelin system, particularly those coupling vascular support and anti-inflammatory action, can prevent the transition of AKI to chronic kidney and cardiovascular disease.

Arterial stiffness, endothelial dysfunction and impaired fibrinolysis are pathogenic mechanisms contributing to cardiovascular risk in ANCA-associated vasculitis

Cardiovascular disease is a complication of systemic inflammatory diseases including anti-neutrophil cytoplasm antibody-associated vasculitis (AAV). The mechanisms of cardiovascular morbidity in AAV are poorly understood, and risk-reduction strategies are lacking. Therefore, in a series of double-blind, randomized case-control forearm plethysmography and crossover systemic interventional studies, we examined arterial stiffness and endothelial function in patients with AAV in long-term disease remission and in matched healthy volunteers (32 each group). The primary outcome for the case-control study was the difference in endothelium-dependent vasodilation between health and AAV, and for the crossover study was the difference in pulse wave velocity (PWV) between treatment with placebo and selective endothelin-A receptor antagonism. Parallel in vitro studies of circulating monocytes and platelets explored mechanisms. Compared to healthy volunteers, patients with AAV had 30% reduced endothelium-dependent vasodilation and 50% reduced acute release of endothelial active tissue plasminogen activator (tPA), both significant in the case-control study. Patients with AAV had significantly increased arterial stiffness (PWV: 7.3 versus 6.4 m/s). Plasma endothelin-1 was two-fold higher in AAV and independently predicted PWV and tPA release. Compared to placebo, both selective endothelin-A and dual endothelin-A/B receptor blockade reduced PWV and increased tPA release in AAV in the crossover study. Mechanistically, patients with AAV had increased platelet activation, more platelet-monocyte aggregates, and altered monocyte endothelin receptor function, reflecting reduced endothelin-1 clearance. Patients with AAV in long-term remission have elevated cardiovascular risk and endothelin-1 contributes to this. Thus, our data support a role for endothelin-blockers to reduce cardiovascular risk by reducing arterial stiffness and increasing circulating tPA activity.

Immune-vascular mural cell interactions: consequences for immune cell trafficking, cerebral blood flow, and the blood-brain barrier

Brain barriers are crucial sites for cerebral energy supply, waste removal, immune cell migration, and solute exchange, all of which maintain an appropriate environment for neuronal activity. At the capillary level, where the largest area of brain-vascular interface occurs, pericytes adjust cerebral blood flow (CBF) by regulating capillary diameter and maintain the blood-brain barrier (BBB) by suppressing endothelial cell (EC) transcytosis and inducing tight junction expression between ECs. Pericytes also limit the infiltration of circulating leukocytes into the brain where resident microglia confine brain injury and provide the first line of defence against invading pathogens. Brain "waste" is cleared across the BBB into the blood, phagocytosed by microglia and astrocytes, or removed by the flow of cerebrospinal fluid (CSF) through perivascular routes-a process driven by respiratory motion and the pulsation of the heart, arteriolar smooth muscle, and possibly pericytes. "Dirty" CSF exits the brain and is probably drained around olfactory nerve rootlets and via the dural meningeal lymphatic vessels and possibly the skull bone marrow. The brain is widely regarded as an immune-privileged organ because it is accessible to few antigen-primed leukocytes. Leukocytes enter the brain via the meninges, the BBB, and the blood-CSF barrier. Advances in genetic and imaging tools have revealed that neurological diseases significantly alter immune-brain barrier interactions in at least three ways: (1) the brain's immune-privileged status is compromised when pericytes are lost or lymphatic vessels are dysregulated; (2) immune cells release vasoactive molecules to regulate CBF, modulate arteriole stiffness, and can plug and eliminate capillaries which impairs CBF and possibly waste clearance; and (3) immune-vascular interactions can make the BBB leaky via multiple mechanisms, thus aggravating the influx of undesirable substances and cells. Here, we review developments in these three areas and briefly discuss potential therapeutic avenues for restoring brain barrier functions.

Anlotinib-Induced Hypertension: Current Concepts and Future Prospects

BACKGROUND

Anlotinib is a new tyrosine kinase inhibitor developed in China that targets the receptors for vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, and stem cell factor. Therefore, anlotinib inhibits tumor angiogenesis, representing a new therapeutic alternative for lung cancer. Hypertension is one of its most common adverse effects, leading to discontinuation of the drug and limited clinical usefulness.

OBJECTIVE

The present review aims to summarize the evidence on the prevalence, physiopathology, and management of anlotinib-induced hypertension, as well as its effect on the cancer prognosis.

METHOD

Searches in Medline, Cochrane Central Library, and Embase were performed using the following terms: anlotinib, adverse effect, hypertension, clinical trial, vascular endothelial growth factor, and antiangiogenic drugs. Citations were also identified by checking the reference sections of selected papers.

RESULTS

Except for a phase I clinical trial with a small sample size (n = 6), almost all the clinical trials on anlotinib have reported the development of anlotinib-induced hypertension. In these trials, the incidence of hypertension ranged from 13% to 67.7%, and that of grade 3/4 hypertension ranged from4.8% to 16%. Alterations in nitric oxide, endothelin-1, microvascular rarefaction, selective vasoconstrictions, and renal injury have been cited as potential mechanisms leading to anlotinib-induced hypertension. When needed, treatment may include general hygienic measures and pharmacotherapy in some cases.

CONCLUSIONS

To effectively manage anlotinib-induced hypertension, early prevention, a reasonable dosage regimen, and appropriate treatment are critical to effectively manage anlotinib-induced hypertension. Additionally, anlotinib-induced hypertension may be considered a marker for predicting efficacy.

Proteins from the DNA Damage Response: Regulation, Dysfunction, and Anticancer Strategies

Cells respond to genotoxic stress through a series of complex protein pathways called DNA damage response (DDR). These monitoring mechanisms ensure the maintenance and the transfer of a correct genome to daughter cells through a selection of DNA repair, cell cycle regulation, and programmed cell death processes. Canonical or non-canonical DDRs are highly organized and controlled to play crucial roles in genome stability and diversity. When altered or mutated, the proteins in these complex networks lead to many diseases that share common features, and to tumor formation. In recent years, technological advances have made it possible to benefit from the principles and mechanisms of DDR to target and eliminate cancer cells. These new types of treatments are adapted to the different types of tumor sensitivity and could benefit from a combination of therapies to ensure maximal efficiency.

The effect of macrophage-targeted interventions on blood pressure - a systematic review and meta-analysis of preclinical studies

An increasing body of evidence shows a role for macrophages and monocytes (as their precursors) in hypertension, but with conflicting results with regard to whether they are protective or harmful. Therefore, we systematically reviewed the effect of macrophage interventions on blood pressure in animal models, to explore which factors determine the blood pressure increasing vs. decreasing effect. A search in PubMED and EMBASE yielded 9620 records, 26 of which were included. Eighteen studies (involving 22 different experiments (k = 22)) performed macrophage depletion, whereas 12 studies specifically deleted certain macrophage proteins. The blood pressure effects of macrophage depletion were highly various and directed toward both directions, as expected, which could not be reduced to differences in animal species or methods of hypertension induction. Prespecified subgroup analysis did reveal a potential role for the route in which the macrophage-depleting agent is being administrated (intraperitoneal vs intravenous subgroup difference of P = 0.07 (k = 22), or P < 0.001 in studies achieving considerable (ie, >50%) depletion (k = 18)). Along with findings from specific macrophage protein deletion studies-showing that deletion of one single macrophage protein (like TonEBP, endothelin-B, EP₄, NOX-2 and the angiotensin II type 1 receptor) can alter blood pressure responses to hypertensive stimuli-the indication that each route has its specific depletion pattern regarding targeted tissues and macrophage phenotypes suggests a determinative role for these features. These hypothesis-generating results encourage more detailed depletion characterization of each technique by direct experimental comparisons, providing a chance to obtain more knowledge on which macrophages are beneficial versus detrimental in hypertension development.

Inducible mechanisms of disease tolerance provide an alternative strategy of acquired immunity to malaria

Immunity to malaria is often considered slow to develop but this only applies to defense mechanisms that function to eliminate parasites (resistance). In contrast, immunity to severe disease can be acquired quickly and without the need for improved pathogen control (tolerance). Using Plasmodium chabaudi, we show that a single malaria episode is sufficient to induce host adaptations that can minimise inflammation, prevent tissue damage and avert endothelium activation, a hallmark of severe disease. Importantly, monocytes are functionally reprogrammed to prevent their differentiation into inflammatory macrophages and instead promote mechanisms of stress tolerance to protect their niche. This alternative fate is not underpinned by epigenetic reprogramming of bone marrow progenitors but appears to be imprinted within the remodelled spleen. Crucially, all of these adaptations operate independently of pathogen load and limit the damage caused by malaria parasites in subsequent infections. Acquired immunity to malaria therefore prioritises host fitness over pathogen clearance.

The varying roles of macrophages in kidney injury and repair

PURPOSE OF REVIEW

Macrophages play an important role in regulating homeostasis, kidney injury, repair, and tissue fibrogenesis. The present review will discuss recent advances that explore the novel subsets and functions of macrophage in the pathogenesis of kidney damage and hypertension.

RECENT FINDINGS

Macrophages differentiate into a variety of subsets in microenvironment-dependent manner. Although the M1/M2 nomenclature is still applied in considering the pro-inflammatory versus anti-inflammatory effects of macrophages in kidney injury, novel, and accurate macrophage phenotypes are defined by flow cytometric markers and single-cell RNA signatures. Studies exploring the crosstalk between macrophages and other cells are rapidly advancing with the additional recognition of exosome trafficking between cells. Using murine conditional mutants, actions of macrophage can be defined more precisely than in bone marrow transfer models. Some studies revealed the opposing effects of the same protein in renal parenchymal cells and macrophages, highlighting a need for the development of cell-specific immune therapies for translation.

SUMMARY

Macrophage-targeted therapies hold potential for limiting kidney injury and hypertension. To realize this potential, future studies will be required to understand precise mechanisms in macrophage polarization, crosstalk, proliferation, and maturation in the setting of renal disease.

Role of Drugs Used for Chronic Disease Management on Susceptibility and Severity of COVID-19: A Large Case-Control Study

This study aimed to investigate whether specific medications used in the treatment chronic diseases affected either the development and/ or severity of coronavirus disease 2019 (COVID-19) in a cohort of 610 COVID-19 cases and 48,667 population-based controls from Zhejiang, China. Using a cohort of 578 COVID-19 cases and 48,667 population-based controls from Zhejiang, China, we tested the role of usage of cardiovascular, antidiabetic, and other medications on risk and severity of COVID-19. Analyses were adjusted for age, sex, and body mass index and for presence of relevant comorbidities. Individuals with hypertension taking calcium channel blockers had significantly increased risk (odds ratio (OR) = 1.73, 95% confidence interval (CI) 1.2-2.3) of manifesting symptoms of COVID-19, whereas those taking angiotensin receptor blockers and diuretics had significantly lower disease risk (OR = 0.22, 95% CI 0.15-0.30 and OR = 0.30, 95% CI 0.19-0.58, respectively). Among those with type 2 diabetes, dipeptidyl peptidase-4 inhibitors (OR = 6.02, 95% CI 2.3-15.5) and insulin (OR = 2.71, 95% CI 1.6-5.5) were more and glucosidase inhibitors were less prevalent (OR = 0.11, 95% CI 0.1-0.3) among with patients with COVID-19. Drugs used in the treatment of hypertension and diabetes influence the risk of development of COVID-19, but, not its severity.

Biological Context Linking Hypertension and Higher Risk for COVID-19 Severity

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), represents a public health crisis of major proportions. Advanced age, male gender, and the presence of comorbidities have emerged as risk factors for severe illness or death from COVID-19 in observation studies. Hypertension is one of the most common comorbidities in patients with COVID-19. Indeed, hypertension has been shown to be associated with increased risk for mortality, acute respiratory distress syndrome, need for intensive care unit admission, and disease progression in COVID-19 patients. However, up to the present time, the precise mechanisms of how hypertension may lead to the more severe manifestations of disease in patients with COVID-19 remains unknown. This review aims to present the biological plausibility linking hypertension and higher risk for COVID-19 severity. Emphasis is given to the role of the renin-angiotensin system and its inhibitors, given the crucial role that this system plays in both viral transmissibility and the pathophysiology of arterial hypertension. We also describe the importance of the immune system, which is dysregulated in hypertension and SARS-CoV-2 infection, and the potential involvement of the multifunctional enzyme dipeptidyl peptidase 4 (DPP4), that, in addition to the angiotensin-converting enzyme 2 (ACE2), may contribute to the SARS-CoV-2 entrance into target cells. The role of hemodynamic changes in hypertension that might aggravate myocardial injury in the setting of COVID-19, including endothelial dysfunction, arterial stiffness, and left ventricle hypertrophy, are also discussed.

Activation of the Sympathetic Nervous System Promotes Blood Pressure Salt-Sensitivity in C57BL6/J Mice

Global salt intake averages >8 g/person per day, over twice the limit advocated by the American Heart Association. Dietary salt excess leads to hypertension, and this partly mediates its poor health outcomes. In ≈30% of people, the hypertensive response to salt is exaggerated. This salt-sensitivity increases cardiovascular risk. Mechanistic cardiovascular research relies heavily on rodent models and the C57BL6/J mouse is the most widely used reference strain. We examined the effects of high salt intake on blood pressure, renal, and vascular function in the most commonly used and commercially available C57BL6/J mouse strain. Changing from control (0.3% Na⁺) to high salt (3% Na⁺) diet increased systolic blood pressure in male mice by ≈10 mm Hg within 4 days of dietary switch. This hypertensive response was maintained over the 3-week study period. Returning to control diet gradually reduced blood pressure back to baseline. High-salt diet caused a rapid and sustained downregulation in mRNA encoding renal NHE3 (sodium-hydrogen-exchanger 3) and EnaC (epithelial sodium channel), although we did not observe a suppression in aldosterone until ≈7 days. During the development of salt-sensitivity, the acute pressure natriuresis relationship was augmented and neutral sodium balance was maintained throughout. High-salt diet increased ex vivo sensitivity of the renal artery to phenylephrine and increased urinary excretion of adrenaline, but not noradrenaline. The acute blood pressure-depressor effect of hexamethonium, a ganglionic blocker, was enhanced by high salt. Salt-sensitivity in commercially sourced C57BL6/J mice is attributable to sympathetic overactivity, increased adrenaline, and enhanced vascular sensitivity to alpha-adrenoreceptor activation and not sodium retention or attenuation of the acute pressure natriuresis response.

Association of pre-pro-endothelin gene polymorphism and serum endothelin-1 with intradialytic hypertension in an Egyptian population

BACKGROUND

Intradialytic hypertension (IDH) is a major problem of hemodialysis and it is a multifactorial disorder and need early identification and management.

AIM

Evaluate the serum concentration of endothelin-1 in patients with IDH and healthy control and the impact of pre-pro-endothelin gene polymorphism on level of endothelin-1 and susceptibility to IDH in Egyptian population.

METHODS

The patient groups divided into group I, End stage renal disease (ESRD) on chronic hemodialysis with IDH (112); group II, ESRD on chronic hemodialysis without IDH (112); group III, healthy control (112). All undergone to full history, clinical examination, routine laboratory investigations, echocardiography, serum ET-1 level by ELISA and A(8002)G polymorphism detection in pre-pro-endothelin gene by PCR-RFLP.

RESULTS

Our results showed significantly higher concentration of Endothelin-1 (ET-1) in both patient groups than healthy control and in group with IDH than cases without IDH (p < 0.001). GG, GA and mutated G allele carry the risk of IDH (OR = 15.94, 13.5, 5.51 respectively p < 0.001). There was association between GG and GA genotypes and higher ET-1 level in both patient groups (p < 0.001) and association between GG and GA genotype and higher mean arterial pressure (MAP), delta MAP (DMAP) and increased left ventricular mass index (LVMI) in both patient groups (p = 0.001, 0.028).

CONCLUSION

Pre-pro-endothelin gene polymorphism A(8002)G is an independent risk factor for IDH through changing the level of ET-1 concentration in Egyptian population undergoing chronic hemodialysis.

Periodontitis is associated with hypertension: a systematic review and meta-analysis

Recent evidence suggests a link between periodontitis (PD) and hypertension, but the nature of this association remains unclear. The overall aim of this review was to critically appraise the evidence linking these two common disorders. Systematic search was conducted for studies published up to December 2018. Prevalence of hypertension in patients with PD (moderate/severe groups) vs. those without PD (non-PD) was the primary outcome. Additional outcomes included adjusted mean difference in systolic (SBP) and diastolic (DBP) blood pressure (BP) levels in PD vs. non-PD, assessment of biomarkers in PD and hypertension, and BP changes after periodontal therapy. From 81 studies selected, 40 were included in quantitative meta-analyses. Diagnoses of moderate-severe PD [odds ratio (OR) = 1.22; 95% confidence interval (CI): 1.10-1.35] and severe PD (OR = 1.49; 95% CI: 1.09-2.05) were associated with hypertension. Prospective studies confirmed PD diagnosis increased likelihood of hypertension occurrence (OR = 1.68; 95% CI: 0.85-3.35). Patients with PD exhibited higher mean SBP [weighted mean difference (WMD) of 4.49 mmHg; 95% CI: 2.88-6.11] and DBP (2.03 mmHg; 95% CI: 1.25-2.81) when compared with non-PD. Lastly, only 5 out of 12 interventional studies confirmed a reduction in BP following periodontal therapy, ranging from 3 to 12.5 mmHg of SBP and from 0 to 10 mmHg of DBP. PD is associated with increased odds of hypertension (SORT C) and higher SBP/DBP levels. The evidence suggesting that PD therapy could reduce BP is inconclusive. Although additional research is warranted on this association, these results suggest that oral health assessment and management of PD could not only improve oral/overall health and quality of life but also be of relevance in the management of patients with hypertension.

Deletion of the myeloid endothelin-B receptor confers long-term protection from angiotensin II-mediated kidney, eye and vessel injury

The endothelin system may be an important player in hypertensive end-organ injury as endothelin-1 increases blood pressure and is pro-inflammatory. The immune system is emerging as an important regulator of blood pressure and we have shown that the early hypertensive response to angiotensin-II infusion was amplified in mice deficient of myeloid endothelin-B (ET_B) receptors (LysM-CreEdnrblox/lox). Hypothesizing that these mice would display enhanced organ injury, we gave angiotensin-II to LysM-CreEdnrblox/lox and littermate controls (Ednrblox/lox) for six weeks. Unexpectedly, LysM-CreEdnrblox/lox mice were significantly protected from organ injury, with less proteinuria, glomerulosclerosis and inflammation of the kidney compared to controls. In the eye, LysM-CreEdnrblox/lox mice had fewer retinal hemorrhages, less microglial activation and less vessel rarefaction. Cardiac remodeling and dysfunction were similar in both groups at week six but LysM-CreEdnrblox/lox mice had better endothelial function. Although blood pressure was initially higher in LysM-CreEdnrblox/lox mice, this was not sustained. A natriuretic switch at about two weeks, due to enhanced ET_B signaling in the kidney, induced a hypertensive reversal. By week six, blood pressure was lower in LysM-CreEdnrblox/lox mice than in controls. At six weeks, macrophages from LysM-CreEdnrblox/lox mice were more anti-inflammatory and had greater phagocytic ability compared to the macrophages of Ednrblox/lox mice. Thus, myeloid cell ET_B receptor signaling drives this injury both through amplifying hypertension and by inflammatory polarization of macrophages.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Associations of EDNRA and EDNRB Polymorphisms with Intracerebral Hemorrhage

OBJECTIVE

The most potent vasoconstrictor, endothelin-1 and its receptors, endothelin receptor A (EDNRA) and endothelin receptor B (EDNRB) are involved in hypertension. Hypertension is a major risk factor of intracerebral hemorrhage (ICH). Recent studies have demonstrated increased plasma endothelin-1 level in ICH patients and relationships between EDNRA and EDNRB genetic variants and ischemic stroke. The aim of the current study was to investigate whether EDNRA and EDNRB polymorphisms are associated with ICH by interacting with blood pressure levels.

METHODS

Five EDNRA and EDNRB polymorphisms were genotyped in this case-control study.

RESULTS

We identified that EDNRA rs5333 T allele might be a protective factor of ICH (adjusted odds ratio [OR] = 0.638, 95% CI: 0.417-0.977, P = 0.038), while EDNRB rs5351 A allele could be a risk factor of ICH (adjusted OR = 1.476, 95% CI: 1.042-2.089, P = 0.028). Moreover, we only found that the GG genotype of EDNRA rs5335 had higher diastolic blood pressure than the GC + CC genotypes in ICH patients (91.69 ± 18.77 vs. 84.71 ± 21.48, P = 0.004).

CONCLUSIONS

These findings support the important role of EDNRA and EDNRB polymorphisms in ICH, and suggest that they do not interact with blood pressure levels on altering ICH risk.