Role of Inflammation and Immunity in Hypertension: Recent Epidemiological, Laboratory, and Clinical Evidence

Exposure to second-hand cigarette smoke exacerbates the progression of osteoarthritis in a surgical induced murine model

Osteoarthritis (OA), formerly understood to be a result of passive wear, is now known to be associated with chronic inflammation. Cigarette smoking promotes systemic inflammation and has been implicated in increased joint OA incidence in some studies, though the recent observational data on the association are contradictory. We hypothesize that second-hand smoke (SHS) treatment will increase the incidence of OA in a mouse model that has been subjected to a surgical destabilization of the medial meniscus (DMM). To test this hypothesis, we applied either SHS treatment or room air (RA) to mice for 28 days post-DMM surgery. Histopathology findings indicated that the knees of SHS mice exhibited more severe OA than their control counterparts. Increased expression of matrix metalloprotease-13 (MMP-13), an important extracellular protease known to degrade articular cartilage, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), an intracellular effector of inflammatory pathways, were observed in the SHS group. These findings provide greater understanding and evidence for a detrimental role of cigarette smoke on OA progression and systemic inflammation.

Relationship of Cardiac Autonomic Modulation with Cardiovascular Parameters in Adults, According to Body Mass Index and Physical Activity

This study aimed to analyze the relationship between cardiac autonomic modulation (CAM) and cardiovascular parameters (blood pressure and resting heart rate) in a sample of 256 adults, grouped by body mass index and sufficient moderate-to-vigorous physical activity (≥150 min/week). The sample showed different cardiovascular parameters and CAM according to body mass index, but not according to physical activity. Adults who are overweight and physically active presented higher relationship between CAM and blood pressure than those who are insufficiently active, similarly to normal weight groups. Recommended levels of physical activity may play an important role in the relationship of HRV with cardiovascular parameters in overweight adults, regardless of sex, age, socioeconomic level, and central fat. Trial registration: Registered at ClinicalTrials.gov (NCT03986879). Graphical abstract.

Antiretroviral therapy reduces but does not normalize immune and vascular inflammatory markers in adults with chronic HIV infection in Kenya

INTRODUCTION

Markers of monocyte/macrophage activation and vascular inflammation are associated with HIV-related cardiovascular diseases (CVD) and mortality. We compared these markers among African people living with HIV (PLWH) and HIV-negative adults, and examined risk factors associated with elevated biomarkers (>75th percentile) in PLWH on antiretroviral therapy (ART).

DESIGN

Cross-sectional study.

METHODS

We measured serum concentrations of a gut integrity biomarker (intestinal-fatty acid binding protein), monocyte/macrophage activation biomarkers (soluble CD14 and CD163), and vascular inflammation biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular adhesion molecule 1 (sVCAM-1)]. We assessed the relationship of these inflammatory parameters with HIV, using logistic regression adjusting for traditional CVD risk factors.

RESULTS

Among the 541 participants, median age was 43 years and half were female. Among 275 PLWH, median CD4 T-cell count and duration of ART use was 509 cells/μl and 8 years, respectively. PLWH had significantly higher prevalence of elevated inflammatory biomarkers compared with HIV-negative individuals even after adjustment for traditional CVD risk factors. Compared with individuals without HIV, the prevalence of elevated biomarkers was highest among persons with detectable viral load and CD4 T-cell counts 200 cells/μl or less. In a subanalysis among PLWH, nadir CD4 T-cell count 200 cells/μl or less was associated with elevated soluble CD14 (sCD14); dyslipidemia with elevated sCD14, sICAM-1, and sVCAM-1; and overweight/obesity with reduced sCD14. Longer ART exposure (>4 years) was associated with reduced sVCAM-1 and sICAM-1.

CONCLUSION

HIV and not traditional CVD risk factors is a primary contributor of monocyte/macrophage activation and inflammation despite ART. Anti-inflammatory therapies in addition to ART may be necessary to reduce these immune dysregulations and improve health outcomes of African PLWH.

Inflammation and hypertension development: A longitudinal analysis of the African-PREDICT study

Background

The role of inflammation in the development of hypertension remains incompletely understood. While single inflammatory mediators have been shown to associate with changes in blood pressure (ΔBP), the role of clusters of inflammatory mediators has been less comprehensively explored. We therefore determined whether individual or clusters of inflammatory mediators from a large biomarker panel were associated with ΔBP over 4.5 years, in young healthy adults.

Methods

We included 358 adults (white, n = 156; black, n = 202) with detailed information on ambulatory blood pressure (BP) at baseline and follow-up. Baseline blood samples were analysed for 22 inflammatory mediators using multiplexing technology. Principal component analysis was used to study associations between clusters of inflammatory mediators and ΔBP.

Results

In the total cohort in multivariable-adjusted regression analyses, percentage change in 24hr systolic BP associated positively with Factors 1 (Interferon-gamma, interleukin (IL)-4, IL-7, IL-10, IL-12, IL-17A, IL-21, IL-23, macrophage inflammatory protein (MIP)-1α, MIP-1β, TNF-α, granulocyte-macrophage colony-stimulating factor (GM-CSF)) and 2 (IL-5, IL-6, IL-8, IL-13). Change in daytime systolic BP associated positively with Factors 1, 2 and 3 (C-Reactive protein, IL-1β, IL-2, MIP-3α). Subgroup analysis found these findings were limited to white study participants. Numerous associations were present between individual inflammatory mediators (Interferon-gamma, GM-CSF, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17A, IL-21, IL-23, MIP-1α and MIP-1β) and ΔBP in the white but not black subgroups.

Conclusion

We found independent relationships between numerous inflammatory mediators (individual and clusters) and ΔBP over 4.5 years. The relationship between inflammatory markers and ΔBP was only found in white participants. ClinicalTrials.gov (Identifier: NCT03292094)..

Development of pyrazole derivatives in the management of inflammation

The therapeutic limitations and poor management of inflammatory conditions are anticipated to impact patients negatively over the coming decades. Following the synthesis of the first pyrazole-antipyrine in 1887, several other derivatives have been screened for anti-inflammatory, analgesic, and antipyretic activities. Arguably, the pyrazole ring, as a major pharmacophore and central scaffold partly, defines the pharmacological profile of several derivatives. In this review, we explore the structural-activity relationship that accounts for the pharmacological profile of pyrazole derivatives and highlights future research perspectives capable of optimizing current advancement in the search for safe and efficacy anti-inflammatory drugs. The flourishing research into the pyrazole derivatives as drug candidates has advanced our understanding of inflammation-related diseases and treatment.

Prevalence, Clinical Manifestations, and Biochemical Data of Hypertensive versus Normotensive Symptomatic Patients with COVID-19: A Comparative Study

Background:

There is a scarcity of data regarding the effect of hypertension on the clinical presentation and outcome of symptomatic patients with COVID-19 infection in comparison with non-hypertensive patients.

Aim of the study:

To describe the clinical presentation, radiological and hematological data of a cohort of symptomatic COVID-19 positive hypertensive patients (n = 50) in comparison with another cohort of normotensive symptomatic COVID-19 positive patients (n = 250) diagnosed at the same time and managed in the same health facilities (from January 2020 to May 2020). Associated comorbidities were assessed, and the Charlson Comorbidity Index was calculated. The outcomes, including duration of hospitalization, length of intensive care unit (ICU) stay, duration of mechanical ventilation, and duration of O2 supplementation, were also assessed.

Results:

The prevalence of hypertension in symptomatic COVID-19 positive patients was 50/300 (16%; the prevalence of hypertension in Qatari adults is ~ 30%). Hypertensive patients had a higher prevalence of diabetes mellitus (DM), chronic kidney disease (CKD), and cardiac dysfunction [(coronary heart disease (CHD) and, congestive heart failure (CHF)] compared to normotensive patients (p: < 0.01). They had a higher Charlson Co-morbidity score (2.3 ± 1.8) compared to the normotensive patients (0.4 ± 0.9) (p: < 0.01). Clinically and radiologically, hypertensive patients had significantly higher percentage of pneumonia, severe pneumonia, and acute respiratory distress syndrome (ARDS) versus normotensive patients (p: < 0.01). Complete blood count (CBC) and differential white cell count (WBC) did not differ between hypertensive and normotensive patients. Hypertensive patients had significantly higher C-reactive protein (CRP) (58.5 ± 84), compared to normotensive patients (28 ± 59) (p: < 0.01). Furthermore, a longer duration of hospitalization, intensive care unit (ICU) stay, mechanical ventilation and oxygen therapy versus normotensive patients was also observed. CRP was correlated significantly with the duration of stay in the ICU and the duration for oxygen supplementation (r = 0.56 and 0.61, respectively; p: <0.01).

Conclusions:

Hypertensive patients with COVID-19 had a higher inflammatory response (higher CRP levels), a significant increase of comorbidities, and a more aggressive course of the disease necessitating a higher rate of ICU admission, longer requirement for hospitalization and oxygen use compared to normotensive patients. (www.actabiomedica.it)

The Impact of Hypertension and Use of Calcium Channel Blockers on Tuberculosis Treatment Outcomes

BACKGROUND

Hypertension induces systemic inflammation, but its impact on the outcome of infectious diseases like tuberculosis (TB) is unknown. Calcium channel blockers (CCB) improve TB treatment outcomes in pre-clinical models, but their effect in patients with TB remain unclear.

METHODS

This retrospective cohort study, including all patients > 18 years receiving treatment for culture-confirmed, drug-sensitive TB from 2000 to 2016 at the National Taiwan University Hospital, assessed the association of hypertension and CCB use with all-cause and infection-related mortality during the first 9 months of TB treatment, as well as sputum-smear microscopy and sputum-culture positivity at 2 and 6 months.

RESULTS

1052 of the 2894 patients (36.4%) had hypertension. Multivariable analysis revealed that hypertension was associated with increased mortality due to all causes (HR 1.57, 95% confidence interval[CI], 1.23-1.99) and infections (HR 1.87, 95%CI, 1.34-2.6), but there was no statistical difference in microbiological outcomes when stratified based on hypertensive group. Dihydropyridine-CCB (DHP-CCB) use was associated with reduced all-cause mortality (HR 0.67, 95%CI: 0.45-0.98) only by univariate Cox regression. There was no association between DHP-CCB use and infection-related mortality (HR 0.78, 95%CI: 0.46-1.34) or microbiological outcomes in univariate or multivariate regression analyses.

CONCLUSIONS

Patients with hypertension have increased all-cause mortality and infection-related mortality during the 9 months following TB treatment initiation. DHP-CCB use may lower all-cause mortality in TB patients with hypertension. The presence of hypertension or the use of CCB did not result in a significant change in microbiological outcomes.

IL-17A as a Potential Therapeutic Target for Patients on Peritoneal Dialysis

Chronic kidney disease (CKD) is a health problem reaching epidemic proportions. There is no cure for CKD, and patients may progress to end-stage renal disease (ESRD). Peritoneal dialysis (PD) is a current replacement therapy option for ESRD patients until renal transplantation can be achieved. One important problem in long-term PD patients is peritoneal membrane failure. The mechanisms involved in peritoneal damage include activation of the inflammatory and immune responses, associated with submesothelial immune infiltrates, angiogenesis, loss of the mesothelial layer due to cell death and mesothelial to mesenchymal transition, and collagen accumulation in the submesothelial compact zone. These processes lead to fibrosis and loss of peritoneal membrane function. Peritoneal inflammation and membrane failure are strongly associated with additional problems in PD patients, mainly with a very high risk of cardiovascular disease. Among the inflammatory mediators involved in peritoneal damage, cytokine IL-17A has recently been proposed as a potential therapeutic target for chronic inflammatory diseases, including CKD. Although IL-17A is the hallmark cytokine of Th17 immune cells, many other cells can also produce or secrete IL-17A. In the peritoneum of PD patients, IL-17A-secreting cells comprise Th17 cells, γδ T cells, mast cells, and neutrophils. Experimental studies demonstrated that IL-17A blockade ameliorated peritoneal damage caused by exposure to PD fluids. This article provides a comprehensive review of recent advances on the role of IL-17A in peritoneal membrane injury during PD and other PD-associated complications.

Interleukin-17A induces vascular remodeling of small arteries and blood pressure elevation

An important link exists between hypertension and inflammation. Hypertensive patients present elevated circulating levels of proinflammatory cytokines, including interleukin-17A (IL-17A). This cytokine participates in host defense, autoimmune and chronic inflammatory pathologies, and cardiovascular diseases, mainly through the regulation of proinflammatory factors. Emerging evidence also suggests that IL-17A could play a role in regulating blood pressure and end-organ damage. Here, our preclinical studies in a murine model of systemic IL-17A administration showed that increased levels of circulating IL-17A raised blood pressure induced inward remodeling of small mesenteric arteries (SMAs) and arterial stiffness. In IL-17A-infused mice, treatment with hydralazine and hydrochlorothiazide diminished blood pressure elevation, without modifying mechanical and structural properties of SMA, suggesting a direct vascular effect of IL-17A. The mechanisms of IL-17A seem to involve an induction of vascular smooth muscle cell (VSMC) hypertrophy and phenotype changes, in the absence of extracellular matrix (ECM) proteins accumulation. Accordingly, treatment with an IL-17A neutralizing antibody diminished SMA remodeling in a model of angiotensin II (Ang II) infusion. Moreover, in vitro studies in VSMCs reported here, provide further evidence of the direct effects of IL-17A on cell growth responses. Our experimental data suggest that IL-17A is a key mediator of vascular remodeling of the small arteries, which might contribute, at least in part, to blood pressure elevation.

Is Hypertension a Real Risk Factor for Poor Prognosis in the COVID-19 Pandemic?

Purpose of Review

There is increasing evidence indicating an association between several risk factors and worse prognosis in patients with coronavirus disease 2019 (COVID-19), including older age, hypertension, heart failure, diabetes, and pulmonary disease. Hypertension is of particular interest because it is common in adults and there are concerns related to the use of renin-angiotensin system (RAS) inhibitors in patients with hypertension infected with COVID-19. Levels of angiotensin-converting enzyme 2 (ACE2), a protein that facilitates entry of coronavirus into cells, may increase in patients using RAS inhibitors. Thus, chronic use of RAS inhibition could potentially lead to a more severe and fatal form of COVID-19. In this review, we provide a critical review to the following questions: (1) Does hypertension influence immunity or ACE2 expression favoring viral infections? (2) Are the risks of complications in hypertension mediated by its treatment? (3) Is aging a major factor associated with worse prognosis in patients with COVID-19 and hypertension?

Recent Findings

Despite the potential involvement of immune responses in the pathogenesis of hypertension, there is no evidence supporting that hypothesis that hypertension or RAS inhibitors contributes to unfavorable outcomes in viral infections. Future investigations adopting a strict protocol for confirming hypertension status as well as assessing associated comorbidities that may influence outcomes are necessary. From the therapeutic perspective, recombinant ACE2 may serve as a potential therapy, but relevant studies in humans are lacking. Definitive evidence regarding the use of RAS inhibitors in patients with COVID-19 is needed; 5 randomized trials examining this issue are currently underway.

Summary

There is no current scientific support for claiming that hypertension or its treatment with RAS inhibitors contribute to unfavorable outcomes in COVID-19.

Biointerface topography regulates phenotypic switching and cell apoptosis in vascular smooth muscle cells

BACKGROUND

In-stent restenosis (ISR) is a complex disease that occurs after coronary stenting procedures. The development of quality materials and improvement of our understanding on significant factors regulating ISR are essential for enhancing prognosis. Vascular smooth muscle cells (VSMCs) are the main constituent cells of blood vessel walls, and dysfunction of VMSCs can exacerbate ISR. Accordingly, in this study, we explored the influence of wrinkled material topography on the biological functions of VSMCs.

METHODS

Polydimethylsiloxane with a wrinkled topography was synthesized using elastomer base and crosslinking and observed by atomic force microscopy. VSMC proliferation, apoptosis, and morphology were determined by Cell Counting Kit-8 assays, fluorescence-assisted cell sorting, and phalloidin staining. α-Smooth muscle actin (α-SMA), major histocompatibility complex (MHC), and calponin 1 (CNN-1) expression levels were measured by quantitative real-time polymerase chain reaction and western blotting. Moreover, p53 and cleaved caspase-3 expression levels were evaluated by western blotting in VSMCs to assess apoptotic induction.

RESULTS

Surface topographies were not associated with a clear orientation or elongation of VSMCs. The number of cells was increased on wrinkled surfaces (0.7 μm in amplitude, and 3 μm in wavelength [W3]) compared with that on other surfaces, contributing to continuously increased cell proliferation. Moreover, interactions of VSMCs with the W3 surface suppressed phenotypic switching, resulting in ISR via regulation of α-SMA, calponin-1, and SM-MHC expression. The surface with an amplitude of 0.05 μm and a wavelength of 0.5 μm (W0.5) promoted apoptosis by inducing caspase 3 and p53 activities.

CONCLUSION

Introduction of aligned topographies on biomaterial scaffolds could provide physical cues to modulate VSMC responses for engineering vascular constructs. Materials with wrinkled topographies could have applications in the development of stents to reduce ISR.

Naringin regulates erectile dysfunction by abolition of apoptosis and inflammation through NOS/cGMP/PKG signalling pathway on exposure to Bisphenol-A in hypertensive rat model

This study investigated the effect of naringin (NRG) on extracellular metabolism of ATP through the NOS/cGMP/PKG signaling pathway induced by Nω-nitro-L-arginine methyl ester hydrochloride (_L-NAME) on exposure to Bisphenol-A (BPA) in penis. Fifty-six adult male albino rats were randomly distributed into eight (n = 7) groups. Group I: control animals, Group II was treated with 40 mg/kg _L-NAME, Group III was treated with 50 mg/kg BPA, Group IV was treated with 40 mg/kg _L-NAME +50 mg/kg BPA. Group V was administered with 40 mg/kg _L-NAME +80 mg/kg NRG. Group VI was administered with 50 mg/kg BPA + 80 mg/kg NRG. Group VII was administered with 40 mg/kg _L-NAME+50 mg/kg BPA + 80 mg/kg NRG. Lastly, group VIII was treated with 80 mg/kg NRG for 14 days. NRG prevented hypertension and erectile dysfunction by inhibiting the activities of angiotensin-converting enzymes, arginase, and phosphodiesterase-5¹ (PDE-5¹) with corresponding down-regulation of inflammatory markers including TNF-α and IL-B. Additionally, hypertensive erectile dysfunction was remarkably prevented by NRG as manifested by the declined activities of AChE, MAO-A and enzymes of ATP hydrolysis (ATPase, ADPase, AMPase and ADA) with resultant increase in NO level. Also, penile expression of antigen presenting cells, CD43 transcript, caspace-9 and tumor suppressor P53 proteins were repressed on treatment with NRG. This study validates the hypothesis that NRG may be a valuable remedy in abrogating penile inflammatory markers, apoptosis and enzymes of ATP-hydrolysis via NOS/cGMP/PKG signaling pathways in hypertensive rat model on exposure to environmental toxicant.

Greater T Regulatory Cells in Females Attenuate DOCA-Salt-Induced Increases in Blood Pressure Versus Males

Hypertension is the most common risk factor for cardiovascular disease, causing over 18 million deaths a year. Although the mechanisms controlling blood pressure (BP) in either sex remain largely unknown, T cells play a critical role in the development of hypertension. Further evidence supports a role for the immune system in contributing to sex differences in hypertension. The goal of the current study was to first, determine the impact of sex on the renal T-cell profiles in DOCA-salt hypertensive males and females and second, test the hypothesis that greater numbers of T regulatory cells (Tregs) in females protect against DOCA-salt-induced increases in BP and kidney injury. Male rats displayed greater increases in BP than females following 3 weeks of DOCA-salt treatment, although increases in renal injury were comparable between the sexes. DOCA-salt treatment resulted in an increase in proinflammatory T cells in both sexes; however, females had more anti-inflammatory Tregs than males. Additional male and female DOCA-salt rats were treated with anti-CD25 to decrease Tregs. Decreasing Tregs significantly increased BP only in females, thereby abolishing the sex difference in the BP response to DOCA-salt. This data supports the hypothesis that Tregs protect against the development of hypertension and are particularly important for the control of BP in females.

Role of immunological disorders, endothelial dysfunction and hemostatic disorders in the genesis of arterial hypertension in the metabolic syndrome

Mortality from diseases of the circulatory system is a challenge for the modern health care. Arterial hypertension (AH) mostly contributes to development of cardiovascular complications. It often proceeds against the background of metabolic disorders. Pathogenesis of hypertension is currently being considered a multifactorial disease. Pathogenesis of hypertension certainly has distinct features in presence of metabolic disorders,. Therefore, it is relevant to summarize current literature on the role of immunological disorders, endothelial dysfunction and hemostatic disorders in AH genesis during metabolic syndrome (MS). Most authors agree with existence of several mechanisms that determine relationships between AH and insulin resistance. Development of hypertension in MS patients with is a consequence of immunometabolic processes. Abdominal obesity is an important component of MS. It is associated with chronic inflammation of visceral adipose tissue, its excessive infiltration by immune cells, and increased production of adipokines and cytokines (TNFα, IL-6) with hypertension. AH is associated with a significant increase in T cells, that mediate endothelial dysfunction (ED) and provide a link between hypertension and subsequent atherosclerosis. T lymphocytes trigger a cascade of reactions. IL-17 is the end product of these events It is involved not only in increasing blood pressure, but also contributes to the development of vascular wall stiffness in АН patients. Thus, the relationship between several types of immune cells leads to inflammatory reactions, including those of vascular wall, initiating endothelial dysfunction. Chronic non-specific inflammation in MS, supported by the cytokine system, is a triggering mechanism for ED progression. Excessive production of endothelin-1 and inhibition of nitric oxide production are the classic markers of ED. Immune damage leads to imbalance in the production of vasoconstrictor and vasodilating substances, proliferative and antiproliferative factors in endothelium. It was shown that ED is an integral aspect of the insulin resistance syndrome in pathogenesis of arterial hypertension associated with metabolic disorders, and contributes to its worsening, increased vascular reactivity and further AH development. According to modern studies, it has been shown that excessive synthesis of pro-inflammatory cytokines introduces disturbances in the system of vascular hemostasis. When studying the effects of metabolic disorders upon hemostatic system, we may conclude that activation of fibrinolytic and plasma chains occurs in the same way for both men and women, with small gender characteristics of individual components. The rheological properties of the blood are also changed with developing MS. Systematization of the available literature data on the issue under study can serve as a basis for determining prognostic criteria of hypertension progression and risk of thrombotic complications.

Plasma levels of matrix metalloproteinase-9 are elevated in individuals with hypertensive crisis

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) participates in the degradation of components of the extracellular matrix and it is involved in vascular remodeling and vasomotor changes. The aim of this study was to investigate the plasma levels of MMP-9 in acute vascular alterations due to hypertensive crisis.

METHODS

This cross-sectional study was performed in 40 normotensive (NT) and 58 controlled hypertensive subjects (CHyp) followed up in outpatient clinic. Moreover, 57 patients with hypertensive emergency (HypEmerg) and 43 in hypertensive urgency (HypUrg), seen in emergency department, were also included. Hypertensive crisis was divided into HypEmerg, which was characterized by levels of systolic blood pressure (BP) ≥ 180 mmHg and/or diastolic BP ≥ 120 mmHg complicated with target-organ damage (TOD), and HypUrg, defined by BP elevation without TOD. Univariate and multivariate regression analysis was performed to identify the influence of independent variables on MMP-9 levels. A p-value < 0.05 was considered statistically significant.

RESULTS

The mean age was 43.5 years in the NT group (11 men); 57.7 years in the CHyp group (29 men); 59.4 years in the HypUrg group (21 men) and 62.4 years in the HypEmerg group (31 men). The age was statistically different in the NT group compared to other 3 groups. The mean BP was 116.5 ± 13.9/72.4 ± 10.6 mmHg for NT, 123.2 ± 12.6/79 ± 9.2 for CHyp, 194.1 ± 24.3/121.4 ± 17.3 for HypUrg and 191.6 ± 34.3/121.7 ± 18.8 mmHg for HypEmerg, respectively (p-value< 0.0001 between groups). MMP-9 levels were statistically different between the HypEmerg (2.31 ± 0.2 ng/mL) and HypUrg groups (2.17 ± 0.3 ng/mL) compared to the NT (1.94 ± 0.3 ng/mL) (p-value < 0.01 and p-value < 0.05, respectively) and CHyp groups (1.92 ± 0.2 ng/mL) (p-value < 0.01). Uric acid was the only independent variable for predicting MMP-9 levels (p-value = 0.001).

CONCLUSION

MMP-9 concentrations are significantly higher in the hypertensive crisis groups (urgency and emergency) compared to the control groups. Therefore, MMP-9 may be a biomarker or mediator of pathophysiologic pathways in cases of acute elevations of blood pressure.

Assessing inflammation and its role in comorbidities among persons living with HIV

PURPOSE OF REVIEW

This article describes the use of biomarkers in expanding our understanding of chronic non-AIDS comorbidities among persons living with HIV (PLWH) receiving antiretroviral therapy (ART).

RECENT FINDINGS

We review current evidence that biomarkers of chronic immune activation and inflammation associate with a broad spectrum of end-organ diseases in PLWH. We discuss how ART may impact inflammation associated with HIV infection and the degree to which inflammation persists despite effective suppression of viral replication in plasma. We then discuss the limitations of the current literature, which lacks evidence of causality and disproportionately involves a few protein biomarkers that are unable to disentangle complex and overlapping biological pathways.

SUMMARY

Premature end-organ disease among PLWH has been repeatedly associated with higher levels of blood biomarkers reflecting inflammation and immune activation, which, despite viral suppression and CD4 T-cell increases after ART treatment, remain elevated relative to uninfected persons. There remain important unanswered questions with implications for the development of anti-inflammatory treatment strategies aimed at mitigating excess risk for end-organ comorbidities among PLWH.

The acute inflammatory response after trauma is heightened by frailty: A prospective evaluation of inflammatory and endocrine system alterations in frailty

BACKGROUND

Frailty is a geriatric syndrome characterized by decreased physiological reserves, increased inflammation, and decreased anabolic-endocrine response. The biomarkers associated with frailty are poorly understood in trauma. The aim of this study was to analyze the association between frailty and immune: IL-1β, IL-6, IL-2Rα, tumor necrosis factor (TNF)-α, and endocrine biomarkers: insulin-like growth factor-1 and growth hormone in trauma patients.

METHODS

We conducted a 1-year (2017-2018) prospective analysis of geriatric (≥65 years) trauma patients admitted to our Level I trauma center. Frailty was measured using the trauma-specific frailty index (TSFI) and blood samples were collected within 24 hours of admission. Patients were stratified into two groups: frail (TSFI > 0.25) and nonfrail (TSFI ≤ 0.25). We then measured the levels of immune and endocrine biomarkers by a colorimetric output that was read by a spectrophotometer (Quantikine ELISA). The outcome measures were the levels of the immune and endocrine markers in the two groups. Multivariable linear regression was performed.

RESULTS

A total of 100 geriatric trauma patients were consented and enrolled. The mean age was 77.1 ± 9.8 years and 34% were female. Thirty-nine (39%) patients were frail. Frail patients were more likely to present after falls (p = 0.01). There was no difference in age (p = 0.78), sex (p = 0.77), systolic blood pressure (p = 0.16), and heart rate (p = 0.24) between the two groups. Frail patients had higher levels of TNF-α (p = 0.01), IL-1β (p = 0.01), and IL-6(p = 0.01) but lower levels of growth hormone (p = 0.03) and insulin-like growth factor-1 (p < 0.04) compared with nonfrail patients. There was no difference in the level of IL-2Rα (p = 0.25). On regression analysis, frailty was positively correlated with the levels of proinflammatory biomarkers, that is, TNF- α, IL-1 β, and IL-6 and negatively correlated with endocrine biomarkers.

CONCLUSION

This study supports the association between frailty and immune and endocrine markers. Frailty acts synergistically with trauma in increasing the acute inflammatory response. Moreover, frail patients have lower levels of anabolic hormones. Understanding the inflammatory and endocrine response in frail trauma patients may result in better therapeutic strategies.

Systemic Arterial Stiffness in New Diagnosed Idiopathic Pulmonary Arterial Hypertension Patients

OBJECTIVE

We suggested: 1) patients with idiopathic pulmonary hypertension (IPAH) have active factors which could damage not only the pulmonary but systemic arteries too as in arterial hypertensive patients; 2) if these changes were present, they might correlate with other parameters influencing on the prognosis. This study is the first attempt to use cardio-ankle vascular index (CAVI) for the evaluation of systemic arterial stiffness in patients with IPAH.

METHODS

A total of 112 patients were included in the study: group 1 consisted of 45 patients with new diagnosed IPAH, group 2 included 32 patients with arterial hypertension, and in the control group were 35 healthy persons adjusted by age. Right heart catheterization, ECG, a 6-minute walk test (6MWT), echocardiography, blood pressure (BP) measurement and ambulatory BP monitoring, pulse wave elastic artery stiffness (PWVe; segment carotid-femoral arteries) and muscular artery stiffness (PWVm; segment carotid-radial arteries), CAVI, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) level were provided. The Spearman correlation, a linear regression and multivariable binary logistic analysis were performed to indicate the predictors associated with PWV and CAVI.

RESULTS

The groups were adjusted for principal characteristics influenced on arterial stiffness. IPAH patients had significantly (P<0.001 for all) shorter 6MWT distance and higher Borg dyspnea score than the patients with arterial hypertension (systolic/diastolic BP = 146.1±10.7/94.2±9.8 mmHg) and the control group = 330.2±14.6 vs 523.8±35.3 and 560.9±30.2 m respectively and 6.2±1.8 vs 1.2±2.1 and 0.9±2.8 points. The PWVm and PWVe were the highest in hypertensive patients (10.3±1.5 and 11.42±1.70 m/s). The control group and IPAH did not have significant differences in aorta BP, but PWVm/PWVe values were significantly (P<0.003/0.008) higher in IPAH patients than in the control group (8.1±1.9/8.49±1.92 vs 6.63±1.34/7.29±0.87 m/s). The CAVIs on both sides were significantly lower in the healthy subjects (5.91±0.99/5.98±0.87 right/left side). Patients with IPAH did not differ from the arterial hypertension patients by CAVIs in comparison with the control group (7.40±1.32/7.22±1.32 vs 7.19±0.78/7.2±1.1 PWVe) did not correlate with any parameters except uric acid. PWVm correlated with uric acid (r=0.58, P<0.001), NT-proBNP (r=0.33, P=0.03) and male gender (r=0.37, P=0.013) at Spearman analysis, but not at multifactorial linear regression analysis. The CAVI correlated with age and parameters characterized functional capacity (6MWT distance) and right ventricle function (NT-proBNP, TAPSE) at Spearman analysis and with age and TAPSE at multifactorial linear regression analysis. At binary logistic regression analysis CAVI > 8.0 at right and/or left side had a correlation with age, 6MWT distance, TAPSE, but an independent correlation was only with age (β=1.104, P=0.008, CI 1.026-1.189) and TAPSE (β=0.66, P=0.016, CI 0.474-0.925).

CONCLUSION

In spite of equal and at normal range BP level, the age-adjusted patients with IPAH had significantly stiffer arteries than the healthy persons and they were comparable with the arterial hypertensive patients. Arterial stiffness evaluated by CAVI correlated with age and TAPSE in IPAH patients. Based on our results it is impossible to conclude the pathogenesis of arterial stiffening in IPAH patients, but the discovered changes and correlations suggest new directions for further studies, including pathogenesis and prognosis researches.

Low-Dose Aspirin Treatment Attenuates Male Rat Salt-Sensitive Hypertension via Platelet Cyclooxygenase 1 and Complement Cascade Pathway

Background The role of platelets in the development of vascular inflammation and endothelial dysfunction in the pathogenesis of hypertension is well established at this time. Aspirin is known to relieve pain, decrease fever, reduce inflammation, impair platelet aggregation, and prevent clotting, yet its effect in the context of salt-sensitive hypertension remains unclear. The present study investigated the importance of aspirin in inhibiting the abnormal activation of platelets and promoting the normal function of the vascular endothelium in a rat model of salt-sensitive hypertension. Method and Results Dahl salt-sensitive rats and salt-resistant rats were fed a normal-salt diet (4% NaCl), a high-salt diet (8% NaCl), or a high-salt diet with aspirin gavage (10 mg/kg per day) for 8 weeks. Blood pressure, platelet activation, vascular function, inflammatory response, and potential mechanism were measured. Low-dose aspirin (10 mg/kg per day) decreased the high-salt diet-induced elevation of blood pressure, platelet activation, leukocyte infiltration, and leukocyte-platelet aggregation (CD45+CD61+), as well as vascular endothelial and renal damage. These effects were related to the ability of aspirin to prevent the adhesion of leukocytes to endothelial cells via inhibition of the platelet cyclooxygenase 1 but not the cyclooxygenase 2 pathway. Aspirin also reversed the high-salt diet-induced abnormal activation of complement and coagulation cascades in platelets. Conclusions These results highlight a new property of aspirin in ameliorating vascular endothelial dysfunction induced by platelet activation, which may be beneficial in the treatment of salt-sensitive hypertension.

Short-Chain Fatty Acid Propionate Protects From Hypertensive Cardiovascular Damage

Supplemental Digital Content is available in the text.

Background:

Arterial hypertension and its organ sequelae show characteristics of T cell–mediated inflammatory diseases. Experimental anti-inflammatory therapies have been shown to ameliorate hypertensive end-organ damage. Recently, the CANTOS study (Canakinumab Antiinflammatory Thrombosis Outcome Study) targeting interleukin-1β demonstrated that anti-inflammatory therapy reduces cardiovascular risk. The gut microbiome plays a pivotal role in immune homeostasis and cardiovascular health. Short-chain fatty acids (SCFAs) are produced from dietary fiber by gut bacteria and affect host immune homeostasis. Here, we investigated effects of the SCFA propionate in 2 different mouse models of hypertensive cardiovascular damage.

Methods:

To investigate the effect of SCFAs on hypertensive cardiac damage and atherosclerosis, wild-type NMRI or apolipoprotein E knockout–deficient mice received propionate (200 mmol/L) or control in the drinking water. To induce hypertension, wild-type NMRI mice were infused with angiotensin II (1.44 mg·kg^–1·d^–1 subcutaneous) for 14 days. To accelerate the development of atherosclerosis, apolipoprotein E knockout mice were infused with angiotensin II (0.72 mg·kg^–1·d^–1 subcutaneous) for 28 days. Cardiac damage and atherosclerosis were assessed using histology, echocardiography, in vivo electrophysiology, immunofluorescence, and flow cytometry. Blood pressure was measured by radiotelemetry. Regulatory T cell depletion using PC61 antibody was used to examine the mode of action of propionate.

Results:

Propionate significantly attenuated cardiac hypertrophy, fibrosis, vascular dysfunction, and hypertension in both models. Susceptibility to cardiac ventricular arrhythmias was significantly reduced in propionate-treated angiotensin II–infused wild-type NMRI mice. Aortic atherosclerotic lesion area was significantly decreased in propionate-treated apolipoprotein E knockout–deficient mice. Systemic inflammation was mitigated by propionate treatment, quantified as a reduction in splenic effector memory T cell frequencies and splenic T helper 17 cells in both models, and a decrease in local cardiac immune cell infiltration in wild-type NMRI mice. Cardioprotective effects of propionate were abrogated in regulatory T cell–depleted angiotensin II–infused mice, suggesting the effect is regulatory T cell–dependent.

Conclusions:

Our data emphasize an immune-modulatory role of SCFAs and their importance for cardiovascular health. The data suggest that lifestyle modifications leading to augmented SCFA production could be a beneficial nonpharmacological preventive strategy for patients with hypertensive cardiovascular disease.

The Role of Inflammasome-Dependent and Inflammasome-Independent NLRP3 in the Kidney

Cytoplasmic nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) forms an inflammasome with apoptosis-associated speck-like protein containing a CARD (ASC) and pro-caspase-1, which is followed by the cleavage of pro-caspase-1 to active caspase-1 and ultimately the activation of IL-1β and IL-18 and induction of pyroptosis in immune cells. NLRP3 activation in kidney diseases aggravates inflammation and subsequent fibrosis, and this effect is abrogated by genetic or pharmacologic deletion of NLRP3. Inflammasome-dependent NLRP3 mediates the progression of kidney diseases by escalating the inflammatory response in immune cells and the cross-talk between immune cells and renal nonimmune cells. However, recent studies have suggested that NLRP3 has several inflammasome-independent functions in the kidney. Inflammasome-independent NLRP3 regulates apoptosis in tubular epithelial cells by interacting with mitochondria and mediating mitochondrial reactive oxygen species production and mitophagy. This review will summarize the mechanisms by which NLRP3 functions in the kidney in both inflammasome-dependent and inflammasome-independent ways and the role of NLRP3 and NLRP3 inhibitors in kidney diseases.

Interleukin 17A Participates in Renal Inflammation Associated to Experimental and Human Hypertension

Hypertension is now considered as an inflammatory disease, and the kidney is a key end-organ target. Experimental and clinical studies suggest that interleukin 17A (IL-17A) is a promising therapeutic target in immune and chronic inflammatory diseases, including hypertension and kidney disease. Elevated circulating IL-17A levels have been observed in hypertensive patients. Our aim was to investigate whether chronically elevated circulating IL-17A levels could contribute to kidney damage, using a murine model of systemic IL-17A administration. Blood pressure increased after 14 days of IL-17A infusion in mice when compared with that in control mice, and this was associated to kidney infiltration by inflammatory cells, including CD3⁺ and CD4⁺ lymphocytes and neutrophils. Moreover, proinflammatory factors and inflammatory-related intracellular mechanisms were upregulated in kidneys from IL-17A-infused mice. In line with these findings, in the model of angiotensin II infusion in mice, IL-17A blockade, using an anti-IL17A neutralizing antibody, reduced kidney inflammatory cell infiltrates and chemokine overexpression. In kidney biopsies from patients with hypertensive nephrosclerosis, IL-17A positive cells, mainly Th17 and γδ T lymphocytes, were found. Overall, the results support a pathogenic role of IL-17A in hypertensive kidney disease-associated inflammation. Therapeutic approaches targeting this cytokine should be explored to prevent hypertension-induced kidney injury.

Association Between Cardiovascular Risk and Perceived Fatigability in Mid-to-Late Life

Background

Cardiovascular disease (CVD) and fatigue commonly co‐occur in older adults, yet the subjective nature of fatigue and its situational dependence leave the true magnitude of this association undefined.

Methods and Results

Six‐hundred and twenty‐five participants with no history of CVD (aged 68.1+12.0 years), from the Baltimore Longitudinal Study of Aging who underwent ≥2 clinic visits between 2007 and 2015 were classified according to sex‐specific predicted 10‐year CVD risk scores using the Framingham CVD risk score (Framingham) and the Pooled Cohort Equation at baseline. Perceived fatigability was assessed using the Borg rating of perceived exertion scale after a 5‐minute treadmill walk (0.67 m/s, 0% grade). Linear models were used to assess the association between baseline CVD risk and perceived fatigability an average of 4.5 years later, adjusted for demographics, behaviors, and medical history. In final models, a 5% higher baseline Pooled Cohort Equation score was associated with greater perceived fatigability at follow‐up (β=0.13 rating of perceived exertion, P=0.008). Stratified analyses suggested this association was stronger among those aged ≤70 years and those with obesity. Of the individual CVD risk score components, older age was most strongly associated with perceived fatigability (β=0.48, P<0.001), followed by women (β=0.11, P=0.002), and treated hypertension (β=0.11, P=0.003). There was no association with the Framingham risk score.

Conclusions

Perceived fatigability was higher among participants with greater CVD risk measured using the Pooled Cohort Equation risk score. The strong associations with hypertension and obesity suggest prevention and promotion of cardiovascular health may also lower perceived fatigability, particularly among those aged ≤70 years or living with obesity.

Curcumin attenuates migration of vascular smooth muscle cells via inhibiting NFκB-mediated NLRP3 expression in spontaneously hypertensive rats

Migration of vascular smooth muscle cell (VSMC) plays a critical role in the pathophysiology of hypertension and several other vascular diseases. Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a bioactive constituent from Curcuma longa, is commonly used as a spice, food additive or dietary pigment. It has several health benefits including antioxidant, anti-inflammatory and anticancer properties. This study examined the roles of curcumin in VSMC migration in hypertension and underlying mechanism. VSMC was isolated and prepared from thoracic aorta of Wistar-Kyoto rats and spontaneously hypertensive rats (SHR). VSMC migration was evaluated with Boyden chamber assay and wound-healing assay. Curcumin attenuated VSMC migration, inhibited nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) expression and reduced interleukin (IL)-1β concentration in VSMC of SHR, which were similar to the effects of NLRP3 knockdown on IL-1β concentration and VSMC migration. Curcumin inhibited NFκB activation in VSMC of SHR, which was similar to the effects of NFκB inhibitor BAY11-7082 on NFκB activation. In another in vitro model of rat VSMC migration, curcumin also inhibited angiotensin II-induced VSMC migration, NFκB activation, NLRP3 expression and IL-1β production. Intragastric administration of curcumin in SHR attenuated hypertension and reduced NFκB activation, NLRP3 and matrix metalloproteinase-9 expressions and aortic media thickness. These results indicate that curcumin inhibits VSMC migration via inhibiting NFκB-mediated NLRP3 expression in VSMC of SHR or in angiotensin II-treated VSMC. Curcumin attenuates hypertension, vascular inflammation and vascular remodeling in SHR.

Fibronectin type III domain containing 5 attenuates NLRP3 inflammasome activation and phenotypic transformation of adventitial fibroblasts in spontaneously hypertensive rats

OBJECTIVE

Phenotypic transformation of adventitial fibroblasts is important in the pathogenesis of hypertension. This study was designed to determine whether fibronectin type III domain containing 5 (FNDC5) alleviates the phenotypic transformation of adventitial fibroblasts in hypertension and the underlying mechanisms.

METHODS AND RESULTS

Experiments were carried out in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) and primary aortic adventitial fibroblasts. FNDC5 was downregulated and NLRP3 inflammasome was activated in aortic adventitia of SHR. FNDC5 overexpression attenuated adventitial fibroblasts phenotypic transformation, excessive synthesis and secretion of matrix components, NLRP3 inflammasome activation and inflammation in adventitial fibroblasts from SHR. Moreover, FNDC5 overexpression reduced NADPH oxidase 2 (NOX2) expression and reactive oxygen species (ROS) production in adventitial fibroblasts from SHR. Similarly, exogenous FNDC5 inhibited adventitial fibroblasts phenotypic transformation, expression of matrix components, NLRP3 inflammasome activation and NOX2 expression in adventitial fibroblasts from SHR. FNDC5 overexpression in rats attenuated phenotypic transformation, inflammation and reactive oxygen species (ROS) production in the aortic adventitia of SHR. Furthermore, FNDC5 overexpression reduced blood pressure and alleviated vascular remodeling in SHR.

CONCLUSION

FNDC5 reduces NOX2-derived ROS production, NLRP3 inflammasome activation and phenotypic transformation in adventitial fibroblasts of SHR. FNDC5 plays a beneficial role in attenuating vascular inflammation, vascular remodeling and hypertension in SHR.

Patho-immune Mechanisms of Hypertension in HIV: a Systematic and Thematic Review

PURPOSE OF REVIEW

To systematically review recent findings on the role of immune cell activation in the pathogenesis of hypertension in people living with HIV (PLWH) and compare studies from Sub-Saharan Africa with what is reported in the USA and European literature according to guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RECENT FINDINGS

PLWH have an increased risk for development of hypertension and cardiovascular disease. Chronic immune activation contributes to hypertension but the inflammatory milieu that predisposes PLWH to hypertension is poorly understood. We identified 45 relevant studies from 13 unique African countries. The prevalence of hypertension in PLWH on antiretroviral therapy (ART) and the ART-naive PLWH ranged from 6 to 50% and 2 to 41%, respectively. Interleukin (IL)-17A, interferon (IFN)-γ, and higher CD4+ T cell counts were associated with hypertension in ART-treated participants. Targeting adaptive immune activation could provide improved care for hypertensive PLWH. Further research is needed to characterize the inflammatory milieu contributing to hypertension in PLWH especially in African populations where the global burden of HIV is the highest.

A clinical model for identifying an inflammatory phenotype in mood disorders

Increasingly, clinical research has found inflammatory correlates of psychiatric disorders, particularly mood symptomatology. Biological measures may provide greater precision in many cases and may capture clinically-relevant inflammatory signposts, such as central obesity risk, inflammation-associated co-morbid medical conditions, or proinflammatory lifestyle choices. In order to expand understanding of the role of inflammation in mood disorders, we propose a more inclusive clinical model for capturing an inflammatory phenotype of depression by identifying clinically-relevant inflammatory phenotypes grounded in biology. Our model includes chronic conditions and lifestyle behaviors associated with clinically elevated inflammation in mood disorders. Elements of this "inflamed depression" model include: obesity, low HDL concentrations, elevated triglyceride concentrations, chronically elevated blood pressure, clinical diagnosis of hypothyroidism, migraines, rheumatoid arthritis, adult onset diabetes, inflammatory bowel diseases, inflammatory skin conditions, and lifestyle factors including smoking cigarettes and chronic stress.

Brain education-based meditation for patients with hypertension and/or type 2 diabetes: A pilot randomized controlled trial

BACKGROUND

Hypertension and type 2 diabetes are chronic diseases, which generally require lifetime care. Meditation and yoga can be complementary to pharmacological therapies according to the scientific evidences so far. Brain education-based meditation (BEM) is a technique, which has been known to change brain structure, psychology, and physiology of healthy adult participants. This randomized, nonblinded pilot trial aimed to examine whether BEM affects the conditions of patients with hypertension and/or type 2 diabetes compared with health education classes.

METHODS

We randomly allocated 48 patients with hypertension and/or type 2 diabetes to BEM (n = 24) or health education (n = 24) classes in the Ulsan Junggu Public Health Center in Korea, where the classes were run during the same period and explored the impact of 8-week practice on the serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, gamma glutamyl transpeptidase, creatinine, high-density lipoprotein cholesterol, and low-density lipoprotein (LDL) cholesterol. Total RNA was extracted to examine inflammatory gene expressions from the whole blood using PAXgene blood RNA System. In addition, self-reports on mental/physical health were evaluated. The Student's t test, chi-squared test, and analysis of covariance were used for statistical analysis.

RESULTS

The number of people who participated until the completion of the study was 14 in the control and 21 in the BEM group. After 8 weeks, LDL cholesterol level was significantly decreased in the BEM group after the intervention (13.82 mg/dL reduction, P < .05), while it was not significantly altered in the control group. The expression of inflammatory genes was significantly reduced after 8 weeks of the BEM training (0.3-, 0.5-, and 0.2-fold change for NFKB2, RELA, and IL1B, respectively, all P < .05). In the item analysis of mental/physical health self-reports, a significant improvement was confirmed as follows: increases in focus, confidence, relaxation, and happiness; decreases in fatigue, anger, and loneliness (all P < .05). There were no important adverse events or side-effects by BEM intervention.

CONCLUSION

Compared to health education, BEM helps lower LDL cholesterol level and the inflammatory gene expression in the patients with hypertension and/or type 2 diabetes. Moreover, BEM induces positive effects on the self-reported mental/physical states, warranting further study.

Tissue Transglutaminase-Mediated AT1 Receptor Sensitization Underlies Pro-inflammatory Cytokine LIGHT-Induced Hypertension

BACKGROUND

Although numerous recent studies have shown a strong link between inflammation and hypertension, the underlying mechanisms by which inflammatory cytokines induce hypertension remain to be fully elucidated. Hypertensive disorders are also associated with elevated pressor sensitivity. Tissue transglutaminase (TG2), a potent cross-linking enzyme, is known to be transcriptionally activated by inflammatory cytokines and stabilize angiotensin II (Ang II) receptor AT₁ (AT₁R) via ubiquitination-preventing posttranslational modification. Here we sought to investigate the TG2-mediated AT₁R stabilization in inflammation-induced hypertension and its functional consequences with a focus on receptor abundance and Ang II responsiveness.

METHODS AND RESULTS

Using an experimental model of inflammation-induced hypertension established by introducing the pro-inflammatory tumor necrosis factor cytokine LIGHT, we provide pharmacologic and genetic evidence that TG2 is required for LIGHT-induced hypertension (systolic pressure on day 6: LIGHT = 152.3 ± 7.4 vs. LIGHT+ERW1041E [TG2 inhibitor] = 105.8 ± 13.1 or LIGHT+TG2^−/− = 114.3 ± 4.3 mm Hg, P < 0.05, n = 4–5) and renal compromise (urine albumin/creatinine: LIGHT = 0.17 ± 0.05 vs. LIGHT+ERW1041E = 0.03 ± 0.01 or LIGHT+TG2^−/− = 0.06 ± 0.01 mg/mg; plasma creatinine: LIGHT = 1.11 ± 0.04 vs. LIGHT+ERW1041E = 0.94 ± 0.04 or LIGHT+TG2^−/− = 0.88 ± 0.09 mg/dl; urine volume: LIGHT = 0.23 ± 0.1 vs. LIGHT+ERW1041E = 0.84 ± 0.13 or LIGHT+TG2^−/− = 1.02 ± 0.09 ml/24 hour on day 14, P < 0.05, n = 4–5). Our mechanistic studies showed that the TG2-mediated AT₁R modification and accumulation (relative renal AT₁R level: phosphate-buffered saline [PBS] = 1.23 ± 0.22, LIGHT = 3.49 ± 0.37, and LIGHT+ERW1041E = 1.77 ± 0.46, P < 0.05, n = 3; LIGHT+TG2^+/+ = 85.28 ± 36.11 vs. LIGHT+TG2^−/− = 7.01 ± 5.68, P < 0.05, n = 3) induced by LIGHT is associated with abrogated β-arrestin binding (AT₁R/associated β-arrestin ratio: PBS = 2.62 ± 1.07, LIGHT = 38.60 ± 13.91, and LIGHT+ERW1041E = 6.97 ± 2.91, P < 0.05, n = 3; LIGHT+TG2^+/+ = 66.43 ± 44.81 vs. LIGHT+TG2^−/− = 2.45 ± 1.78, P < 0.01, n = 3) and could be found in renal medulla tubules of kidneys (relative tubular AT₁R level: PBS = 5.91 ± 2.93, LIGHT = 92.82 ± 19.54, LIGHT+ERW1041E = 28.49 ± 11.65, and LIGHT+TG2^−/− = 0.14 ± 0.10, P < 0.01, n = 5) and the blood vasculature (relative vascular AT₁R level: PBS = 0.70 ± 0.30, LIGHT = 13.75 ± 2.49, and LIGHT+ERW1041E = 3.28 ± 0.87, P < 0.01, n = 3), 2 of the tissues highly related to the genesis of hypertension. Our in vitro cellular assays showed that LIGHT stimulation triggered a rapid TG2-dependent increase in the abundance of AT₁Rs (relative AT₁R level after 2-hour LIGHT treatment: AT₁R (WT)+TG2 = 2.21 ± 0.23, AT₁R (Q315A)+TG2 = 0.18 ± 0.23, P < 0.05 vs. starting point = 1, n = 2) and downstream calcium signaling (fold increase in NFAT-driven luciferase activity: Saline = 0.02 ± 0.03, Ang II = 0.17 ± 0.08, LIGHT = 0.05 ± 0.04, LIGHT+Ang II = 0.90 ± 0.04 (P < 0.01 vs. Ang II), and LIGHT+Ang II+ERW1041E = 0.15 ± 0.15 (P < 0.01 vs. LIGHT+Ang II), n = 3).

CONCLUSIONS

Our data indicate an essential and systemic role for TG2 in bridging inflammation to hypertension via its posttranslational modifications stabilizing AT₁ receptor and sensitizing Ang II. Our findings also suggest that TG2 inhibitors could be used as a novel group of cardiovascular agents.

Genetic disruption of Npr1 depletes regulatory T cells and provokes high levels of proinflammatory cytokines and fibrosis in the kidneys of female mutant mice

The present study was designed to determine the effects of gene knockout of guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) on immunogenic responses affecting kidney function and blood pressure (BP) in Npr1 (coding for GC-A/NPRA)-null mutant mice. We used female Npr1 gene-disrupted (Npr1^-/-, 0 copy), heterozygous (Npr1^+/-, 1 copy), wild-type (Npr1^+/+, 2 copy), and gene-duplicated (Npr1^++/++, 4 copy) mice. Expression levels of Toll-like receptor (TLR)2/TLR4 mRNA were increased 4- to 5-fold in 1-copy mice and 6- to 10-fold in 0-copy mice; protein levels were increased 2.5- to 3-fold in 1-copy mice and 4- to 5-fold in 0-copy mice. Expression of proinflammatory cytokines and BP was significantly elevated in 1-copy and 0-copy mice compared with 2-copy and 4-copy mice. In addition, 0-copy and 1-copy mice exhibited drastic reductions in regulatory T cells (Tregs). After rapamycin treatment, Tregs were increased by 17% (P < 0.001) in 0-copy mice and 8% (P < 0.001) in 1-copy mice. Renal mRNA and protein levels of TLR2 and TLR4 were decreased by 70% in 0-copy mice and 50% in 1-copy mice. There were significantly higher levels of Tregs and very low levels of TLR2/TLR4 expression in 4-copy mice (P < 0.001). These findings indicate that the disruption of Npr1 in female mice triggers renal immunogenic pathways, which transactivate the expression of proinflammatory cytokines and renal fibrosis with elevated BP in mutant animals. The data suggest that rapamycin treatment attenuates proinflammatory cytokine expression, dramatically increases anti-inflammatory cytokines, and substantially reduces BP and renal fibrosis in mutant animals.

Involvement of the MiR-181b-5p/HMGB1 Pathway in Ang II-induced Phenotypic Transformation of Smooth Muscle Cells in Hypertension

Phenotypic transformation of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling in hypertension. High mobility group box-1 (HMGB1) has been reported to be involved in several pathogenic processes including VSMC proliferation and migration. The present study was designed to determine the role of HMGB1 in VSMC phenotypic transformation in hypertension. First, we demonstrated that HMGB1 was elevated in a model of Ang II-induced VSMC phenotypic transformation, which showed down-regulation of contractile proteins and up-regulation of synthetic proteins. Knockdown of HMGB1 and losartan could block the phenotypic transformation. Next, we identified three potential miRNAs for upstream regulation of HMGB1 by bioinformatic analysis; only miR-181b-5p was significantly down-regulated in Ang II-treated cells. Co-treating the cells with miR-181b-5p mimics suppressed HMGB1 expression as well as the phenotypic transformation, migration, and proliferation. Furthermore, the luciferase reporter gene assay confirmed the direct interaction between miR-181b-5p and HMGB1. Finally, to extend these cell-based studies to clinical patients, we demonstrated that plasma miR-181b-5p levels were decreased, while Ang II and HMGB1 levels, as well as the intima-media thickness (IMT) were increased in hypertensive patients; these effects were reversed following the administration of angiotensin receptor blockers. Based on these observations, we conclude that the down-regulation of miR-181b-5p leads to the elevation of HMGB1 levels in hypertensive patients, which accounts, at least partially, for VSMCs phenotypic transformation and vascular remodeling. Our findings also highlight that the plasma levels of miR-181b-5p and HMGB1 may serve as novel biomarkers for vascular remodeling in the hypertensive patients.

Angiotensin II-induced hypertension and cardiac hypertrophy are differentially mediated by TLR3- and TLR4-dependent pathways

Toll-like receptors (TLR) are key components of the innate immune system that elicit inflammatory responses through the adaptor proteins myeloid differentiation protein 88 (MyD88) and Toll-interleukin receptor domain-containing adaptor protein-inducing interferon-β (TRIF). Previously, we demonstrated that TRIF mediates the signaling of angiotensin II (ANG II)- induced hypertension and cardiac hypertrophy. Since TRIF is activated selectively by TLR3 and TLR4, our goals in this study were to determine the roles of TLR3 and TLR4 in mediating ANG II-induced hypertension and cardiac hypertrophy, and associated changes in proinflammatory gene expression in heart and kidney. In wild-type (WT) mice, ANG II infusion (1,000 ng·kg^-1·min^-1 for 3 wk) increased systolic blood pressure and caused cardiac hypertrophy. In ANG II-infused TLR4-deficient mice (Tlr4^del), hypertrophy was significantly attenuated despite a preserved or enhanced hypertensive response. In contrast, in TLR3-deficient mice (Tlr3^-/-), both ANG II-induced hypertension and hypertrophy were abrogated. In WT mice, ANG II increased the expression of several proinflammatory genes in hearts and kidneys that were attenuated in both TLR4- and TLR3-deficient mice compared with WT. We conclude that ANG II activates both TLR4-TRIF and TLR3-TRIF pathways in a nonredundant manner whereby hypertension is dependent on activation of the TLR3-TRIF pathway and cardiac hypertrophy is dependent on both TLR3-TRIF and TLR4-TRIF pathways. NEW & NOTEWORTHY Angiotensin II (ANG II)-induced hypertension is dependent on the endosomal Toll-like receptor 3 (TLR3)-Toll-interleukin receptor domain-containing adaptor protein-inducing interferon-β (TRIF) pathway of the innate immune system but not on cell membrane localized TLR4. However, ANG II-induced cardiac hypertrophy is regulated by both TLR4-TRIF and TLR3-TRIF pathways. Thus, ANG II-induced rise in systolic blood pressure is independent of TLR4-TRIF effect on cardiac hypertrophy. The TLR3-TRIF pathway may be a potential target of therapeutic intervention.

Association of Periodontal Disease and Edentulism With Hypertension Risk in Postmenopausal Women

BACKGROUND

Multiple cross-sectional epidemiologic studies have suggested an association between periodontal disease and tooth loss and hypertension, but the temporality of these associations remains unclear. The objective of our study was to evaluate the association of baseline self-reported periodontal disease and edentulism with incident hypertension.

METHODS

Study participants were 36,692 postmenopausal women in the Women's Health Initiative-Observational Study who were followed annually from initial periodontal assessment (1998-2003) through 2015 (mean follow-up 8.3 years) for newly diagnosed treated hypertension. Cox proportional hazards regression with adjustment for potential confounders was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Edentulism was significantly associated with incident hypertension in crude (HR (95% CI) = 1.38 (1.28-1.49)) and adjusted (HR (95% CI) = 1.21 (1.11-1.30)) models. This association was stronger among those <60 years compared to ≥60 years (P interaction 0.04) and among those with <120 mm Hg systolic blood pressure, compared to those with ≥120 mm Hg (P interaction 0.004). No association was found between periodontal disease and hypertension.

CONCLUSIONS

These findings suggest that edentulous postmenopausal women may represent a group with higher risk of developing future hypertension. As such improved dental hygiene among those at risk for tooth loss as well as preventive measures among the edentulous such as closer blood pressure monitoring, dietary modification, physical activity, and weight loss may be warranted to reduce disease burden of hypertension. Further studies are needed to clarify these results and further elucidate a potential role of periodontal conditions on hypertension risk.

Longitudinal changes of cardiac troponin and inflammation reflect progressive myocyte stretch and likelihood for hypertension in a Black male cohort: The SABPA study

Inflammation was cross-sectionally associated with subclinical wall remodeling and hypertension. Whether longitudinal changes (∆) in inflammation, myocyte injury (troponin T), and stretch (N-terminal-pro-B-type natriuretic peptide) are associated with hypertension and ECG left ventricular hypertrophy (ECG-LVH) is unclear. The first prospective analysis in Africa assessing these associations included a cohort of Black and White teachers (N = 338; aged 20-63 years). Fasting blood samples were obtained to measure tumor necrosis factor-alpha (TNF-α), cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Ambulatory blood pressure, 2-lead ECG and resting 10-lead ECG values were obtained. A higher mean hypertensive status (62%) was evident in Blacks compared to Whites (44%, p < 0.001). Over 3-years, NT-proBNP increased in both ethnic groups. No associations were evident in women or in White men. In Black men, ECG-LVH at follow-up was positively associated with baseline cTnT (Adj R² 0.43; β = 0.48; 95% CI 0.28-0.68, p < 0.001) and baseline SBP (Adj R² 0.43; β = 0.29; 95% CI 0.09-0.49, p = 0.006). In Black men, baseline TNF-α (OR = 1.49, 95% CI 1.05-2.14, p = 0.03) and decreased ΔTNF-α (OR = 2.07, 95% CI 1.26-3.40, p = 0.004) increased the likelihood for cTnT levels ≥ 4.2 ng/L. Here, baseline NT-proBNP (OR = 1.12, 95% CI 1.01-1.23, p = 0.03) and ΔNT-proBNP progression (OR = 1.09, 95% CI 1.00-1.81, p = 0.04) increased the likelihood for 24-h hypertension. In conclusion, chronically increased levels of markers of myocyte injury accompanied by progressive myocardial stretch, reflective of cardiac metabolic overdemand, may ultimately increase hypertension and ischemic heart disease risk in a cohort of Black males.

Differential expression of MicroRNA let-7e and 296-5p in plasma of Egyptian patients with essential hypertension

Essential hypertension is a chronic medical condition affecting thousands of people worldwide. Hypertension results from interplay of genetic and environmental factors. MicroRNAs regulate gene expression and can be biomarkers for disease. MicroRNA let-7e and microRNA 296-5p have been linked to different cardiovascular diseases. This study aimed to determine association of serum miRNA let-7e and miRNA 296-5p with essential hypertension in Egyptian patients. MicroRNA let-7e and miRNA-296-5p expression was determined in sera of 25 hypertensive patients and 25 normotensive controls by quantitative real-time polymerase chain reaction. Hypertensive patients showed significantly higher expression of miRNA let-7e (3.23-fold increase, p = 0.036) in comparison with normotensive controls. In hypertensive patients, miRNA let-7e expression was positively correlated with increased systolic and diastolic blood pressure. Furthermore, miRNA 296-5p expression was negatively correlated with serum total cholesterol and low-density lipoprotein. Results from this study indicate that miRNA let-7e can potentially be a biomarker for essential hypertension.

Inflammation in Salt-Sensitive Hypertension and Renal Damage

PURPOSE OF REVIEW

Low-grade inflammation drives elevations in blood pressure (BP) and consequent target organ damage in diverse experimental models of hypertension. Here, we discuss recent advances elucidating immune-mediated mechanisms of BP elevation and associated target organ damage.

RECENT FINDINGS

Inflammatory mediators produced by immune cells or target organs act on the kidney, vasculature, skin, and nervous system to modulate hypertension. For example, cells of the innate immune system, including monocytes, neutrophils, and dendritic cells (DCs), can all promote BP elevation via actions in the vasculature and kidney. Macrophages expressing VEGF-C impact non-osmotic sodium storage in the skin that in turn regulates salt sensitivity. Within the adaptive immune system, activated T cells can secrete tumor necrosis factor-alpha (TNF-α), interleukin-17a (IL-17a), and interferon-gamma (IFN-γ), each of which has augmented BP and renal damage in pre-clinical models. Inversely, deficiency of IL-17a in mice blunts the hypertensive response and attenuates renal sodium retention via a serum- and glucocorticoid-regulated kinase 1 (SGK1)-dependent pathway. Linking innate and adaptive immune responses, dendritic cells activated by augmented extracellular sodium concentrations stimulate T lymphocytes to produce pro-hypertensive cytokines. By contrast, regulatory T cells (Tregs) can protect against hypertension and associated kidney injury. Rodent studies reveal diverse mechanisms via which cells of the innate and adaptive immune systems drive blood pressure elevation by altering the inflammatory milieu in the kidney, vasculature, and brain.

Angiotensin-(1-9) reduces cardiovascular and renal inflammation in experimental renin-independent hypertension

Hypertension-induced cardiovascular and renal damage can be mediated by activation of the renin-angiotensin-aldosterone system. There are different factors beyond renin-angiotensin-aldosterone system involved in hypertension and renal damage. Inflammation has emerged as an important mediator of hypertension and cardiovascular and kidney damage. Angiotensin-(1-9), a peptide of the renin-angiotensin system, counter-regulates both the physiological and pathological actions of angiotensin II. Recent data has shown that angiotensin-(1-9) protects the heart and blood vessels from adverse cardiovascular remodeling in experimental models of hypertension and/or heart failure and reduces cardiac fibrosis in stroke-prone, spontaneously hypertensive rats. These effects are mediated by the angiotensin II type 2 receptor (AT2R). However, it remains unknown whether angiotensin-(1-9) also has an anti-inflammatory effect. In the present study, we investigate whether angiotensin-(1-9) reduces inflammation and fibrosis in the heart, arteries, and kidney in a DOCA-salt hypertensive model and explore the mechanisms underlying the amelioration of end-organ damage. DOCA-salt hypertensive rats received: a) vehicle, b) angiotensin-(1-9), c) PD123319 (AT2R blocker), d) angiotensin-(1-9) plus A779 (a Mas receptor blocker) or e) angiotensin-(1-9) plus PD123319, and sham rats were used as a control. Our results showed that angiotensin-(1-9) decreased hypertension and increased vasodilation in DOCA-salt hypertensive rats. These actions were partially inhibited by PD123319. Moreover, angiotensin-(1-9) decreased diuresis, fibrosis, and inflammation. These beneficial effects were not mediated by Mas or AT2R blockers. We concluded that angiotensin-(1-9) protects against volume overload-induced hypertensive cardiovascular and kidney damage by decreasing inflammation in the heart, aortic wall, and kidney, through mechanisms independent of the Mas or AT2R.

Metabolomic characterization of hypertension and dyslipidemia

BACKGROUND

Hypertension and dyslipidemia are two main risk factors for cardiovascular diseases (CVD). Moreover, their coexistence predisposes individuals to a considerably increased risk of CVD. However, the regulatory mechanisms involved in hypertension and dyslipidemia as well as their interactions are incompletely understood.

OBJECTIVES

The aims of our study were to identify metabolic biomarkers and pathways for hypertension and dyslipidemia, and compare the metabolic patterns between hypertension and dyslipidemia.

METHODS

In this study, we performed metabolomic investigations into hypertension and dyslipidemia based on a "healthy" UK population. Metabolomic data from the Husermet project were acquired by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-mass spectrometry. Both univariate and multivariate statistical methods were used to facilitate biomarker selection and pathway analysis.

RESULTS

Serum metabolic signatures between individuals with and without hypertension or dyslipidemia exhibited considerable differences. Using rigorous selection criteria, 26 and 46 metabolites were identified as potential biomarkers of hypertension and dyslipidemia respectively. These metabolites, mainly involved in fatty acid metabolism, glycerophospholipid metabolism, alanine, aspartate and glutamate metabolism, are implicated in insulin resistance, vascular remodeling, macrophage activation and oxidised LDL formation. Remarkably, hypertension and dyslipidemia exhibit both common and distinct metabolic patterns, revealing their independent and synergetic biological implications.

CONCLUSION

This study identified valuable biomarkers and pathways for hypertension and dyslipidemia, and revealed common and different metabolic patterns between hypertension and dyslipidemia. The information provided in this study could shed new light on the pathologic mechanisms and offer potential intervention targets for hypertension and dyslipidemia as well as their related diseases.

Role of immune cells in hypertension

Inflammatory processes have been shown to play an important role in the mechanisms involved in the pathogenesis of hypertension. Innate and adaptive immune responses participate in BP elevation and end-organ damage. Here, we discuss recent studies focusing on novel inflammatory and immune mechanisms that play roles in BP elevation. Different subpopulations of cells involved in innate and adaptive immune responses, such as dendritic cells, monocytes/macrophages and NK cells, on the one hand, and B and T lymphocytes, on the other, contribute to the vascular and kidney injury in hypertension. Unconventional innate-like T cells such as γδ T cells also participate in hypertensive mechanisms by priming both innate and adaptive immune cells, contributing to trigger vascular inflammation and BP elevation. These cells exert their effects in part via production of various cytokines including pro-inflammatory IFN-γ and IL-17 and anti-inflammatory IL-10. The present review summarizes some of these immune mechanisms that participate in the pathophysiology of hypertension. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

New roles of aldosterone and mineralocorticoid receptors in cardiovascular disease: translational and sex-specific effects

Recent advances in the field of mineralocorticoid receptor (MR) and its ligand aldosterone expanded the role of this hormone and its receptor far beyond their initial function as a regulator of Na⁺ and K⁺ homeostasis in epithelial cells. The symposium "New Roles of Aldosterone and Mineralocorticoid Receptors in Cardiovascular Disease: Translational and Sex-Specific Effects" presented at the 38th World Congress of the International Union of Physiological Sciences (Rio de Janeiro, Brazil) highlighted the contribution of extrarenal MRs to cardiovascular disease. This symposium showcased how MRs expressed in endothelial, vascular smooth muscle, and immune cells plays a critical role in the development of vascular disease associated with aging, obesity, and chronic aldosterone stimulation and demonstrated that MR antagonism prevents the acute renal dysfunction and tubular injury induced by ischemia-reperfusion injury. It was also shown that the adipocyte-derived hormone leptin is a new direct regulator of aldosterone secretion and that leptin-mediated aldosterone production is a major contributor to obesity-associated hypertension in women. Sex differences in the role of aldosterone and of endothelial MR in the cardiovascular outcomes of obesity were highlighted. This review summarizes these important emerging concepts regarding the contribution of aldosterone and cell-specific MR to cardiovascular disease in male and female subjects and further supports sex-specific benefits of MR antagonist drugs to be tested in additional populations.

Further dissection of QTLs for salt-induced stroke and identification of candidate genes in the stroke-prone spontaneously hypertensive rat

We previously revealed that two major quantitative trait loci (QTLs) for stroke latency of the stroke-prone spontaneously hypertensive rat (SHRSP) under salt-loading were located on chromosome (Chr) 1 and 18. Here, we attempted further dissection of the stroke-QTLs using multiple congenic strains between SHRSP and a stroke-resistant hypertensive rat (SHR). Cox hazard model among subcongenic strains harboring a chromosomal fragment of Chr-1 QTL region showed that the most promising region was a 2.1 Mbp fragment between D1Rat177 and D1Rat97. The QTL region on Chr 18 could not be narrowed down by the analysis, which may be due to multiple QTLs in this region. Nonsynonymous sequence variations were found in four genes (Cblc, Cxcl17, Cic, and Ceacam 19) on the 2.1 Mbp fragment of Chr-1 QTL by whole-genome sequence analysis of SHRSP/Izm and SHR/Izm. Significant changes in protein structure were predicted in CBL-C and CXCL17 using I-TASSER. Comprehensive gene expression analysis in the kidney with a cDNA microarray identified three candidate genes (LOC102548695 (Zinc finger protein 45-like, Zfp45L), Ethe1, and Cxcl17). In conclusion, we successfully narrowed down the QTL region on Chr 1, and identified six candidate genes in this region.

mPGES-1 (Microsomal Prostaglandin E Synthase-1) Mediates Vascular Dysfunction in Hypertension Through Oxidative Stress

mPGES-1 (microsomal prostaglandin E synthase-1), the downstream enzyme responsible for PGE₂ (prostaglandin E₂) synthesis in inflammatory conditions and oxidative stress are increased in vessels from hypertensive animals. We evaluated the role of mPGES-1-derived PGE₂ in the vascular dysfunction and remodeling in hypertension and the possible contribution of oxidative stress. We used human peripheral blood mononuclear cells from asymptomatic patients, arteries from untreated and Ang II (angiotensin II)-infused mPGES-1^-/- and mPGES-1^+/+ mice, and vascular smooth muscle cells exposed to PGE₂ In human cells, we found a positive correlation between mPGES-1 mRNA and carotid intima-media thickness (r=0.637; P<0.001) and with NADPH oxidase-dependent superoxide production (r=0.417; P<0.001). In Ang II-infused mice, mPGES-1 deletion prevented all of the following: (1) the augmented wall:lumen ratio, vascular stiffness, and altered elastin structure; (2) the increased gene expression of profibrotic and proinflammatory markers; (3) the increased vasoconstrictor responses and endothelial dysfunction; (4) the increased NADPH oxidase activity and the diminished mitochondrial membrane potential; and (5) the increased reactive oxygen species generation and reduced NO bioavailability. In vascular smooth muscle cells or aortic segments, PGE₂ increased NADPH oxidase expression and activity and reduced mitochondrial membrane potential, effects that were abolished by antagonists of the PGE₂ receptors (EP), EP1 and EP3, and by JNK (c-Jun N-terminal kinase) and ERK1/2 (extracellular-signal-regulated kinases 1/2) inhibition. Deletion of mPGES-1 augmented vascular production of PGI₂ suggesting rediversion of the accumulated PGH₂ substrate. In conclusion, mPGES-1-derived PGE₂ is involved in vascular remodeling, stiffness, and endothelial dysfunction in hypertension likely through an increase of oxidative stress produced by NADPH oxidase and mitochondria.

[Role of inducible costimulatory molecule-mediated Th17 cell polarization in renal fibrosis in spontaneously hypertensive rats]

OBJECTIVE

To explore the role of inducible costimulatory molecule (ICOS) signaling pathway-mediated Th17 cells polarization in renal damage in essential hypertension.

METHODS

Four-week-old spontaneously hypertensive rats (SHR) were randomly divided into control (SHR-C) group and intervention (SHR-I) group and subjected to intraperitoneal injections of PBS and ICOS monoclonal antibody for 2 weeks, respectively. Blood pressure of the rats was monitored using noninvasive tail artery blood pressure measuring instrument. The percentage of Th17 cells in the splenocytes was analyzed using flow cytometry, and the expression levels of IL-17A mRNA in the rat's kidneys were detected using RT-PCR. The levels of IL-17A and TGF-β1 in the plasma and kidneys were dynamically detected using ELISA and immunohistochemistry, respectively. Renal pathological changes in the rats were detected using Masson staining.

RESULTS

At the age of 10 and 30 weeks, the rats in SHR-C group had a significantly higher blood pressure than those in SHR-I group (P<0.05 or 0.01). In rats in SHR-C group, Th17 cells percentage in the splenocytes and IL-17A mRNA level in the kidney was significantly higher than those in SHR-I group from the age of 6 weeks (P<0.05). The expressions of IL-17A and TGF-β1 in the plasma and kidney were significantly higher in SHR-C group than that in SHR-I group at 6 weeks (P<0.05). Compared with those in SHR-C group, the rats in SHR-I group showed significant alleviation of renal fibrosis from the age of 30 weeks (P<0.05).

CONCLUSION

The ICOS signaling pathway-mediated Th17 cells polarization plays an important role in renal fibrosis in hypertensive rats.

Decreased circulating T regulatory lymphocytes in obese patients undergoing bariatric surgery

OBJECTIVE

It has been previously demonstrated that T lymphocytes may be involved in the development of hypertension and microvascular remodeling, and that circulating T effector lymphocytes may be increased in hypertension. In particular, Th1 and Th 17 lymphocytes may contribute to the progression of hypertension and microvascular damage while T-regulatory (Treg) lymphocytes seem to be protective in this regard. However, no data is available about patients with severe obesity, in which pronounced microvascular alterations were observed.

DESIGN AND METHODS

We have investigated 32 severely obese patients undergoing bariatric surgery, as well as 24 normotensive lean subjects and 12 hypertensive lean subjects undergoing an elective surgical intervention. A peripheral blood sample was obtained before surgery for assessment of CD4+ T lymphocyte subpopulations. Lymphocyte phenotype was evaluated by flow cytometry in order to assess T-effector and Treg lymphocytes.

RESULTS

A marked reduction of several Treg subpopulations was observed in obese patients compared with controls, together with an increased in CD4+ effector memory T-effector cells.

CONCLUSION

In severely obese patients, Treg lymphocytes are clearly reduced and CD4+ effector memory cells are increased. It may be hypothesized that they might contribute to the development of marked microvascular alterations previously observed in these patients.

Anti-Inflammatory Effects of Melatonin in Obesity and Hypertension

PURPOSE OF REVIEW

Here, we review the known relations between hypertension and obesity to inflammation and postulate the endogenous protective effect of melatonin and its potential as a therapeutic agent. We will describe the multiple effects of melatonin on blood pressure, adiposity, body weight, and focus on mitochondrial-related anti-inflammatory and antioxidant protective effects.

RECENT FINDINGS

Hypertension and obesity are usually associated with systemic and tissular inflammation. The progressive affection of target-organs involves multiple mediators of inflammation, most of them redundant, which make anti-inflammatory strategies ineffective. Melatonin reduces blood pressure, body weight, and inflammation. The mechanisms of action of this ancient molecule of protection involve multiple levels of action, from subcellular to intercellular. Mitochondria is a key inflammatory element in vascular and adipose tissue and a potential pharmacological target. Melatonin protects against mitochondrial dysfunction. Melatonin reduces blood pressure and adipose tissue dysfunction by multiple anti-inflammatory/antioxidant actions and provides potent protection against mitochondria-mediated injury in hypertension and obesity. This inexpensive and multitarget molecule has great therapeutic potential against both epidemic diseases.

Differential effect of angiotensin II and blood pressure on hippocampal inflammation in mice

Background

Angiotensin II (Ang II), a peptide hormone involved in the development of hypertension, causes systemic and cerebral inflammation, affecting brain regions important for blood pressure control. The cause-and-effect relationship between hypertension and inflammation is two-way, but the role of blood pressure in the induction of cerebral inflammation is less clear. The vulnerability of specific brain regions, particularly those important for memory, is also of interest.

Methods

We used molecular biology approaches, immunohistochemistry, and electron microscopy to examine the interdependence between the hypertensive and pro-inflammatory effects of Ang II. We examined the effect of blood pressure by administering a subpressive (200 ng/kg/min) or a pressive Ang II dose (1000 or 1900 ng/kg/min) with and without hydralazine (150 mg/L) for 1 week and used phenylephrine to increase blood pressure independently of the renin-angiotensin system.

Results

Ang II increased ionized calcium-binding adaptor molecule 1 (Iba-1) levels (marker of microgliosis) in the whole brain and in the hippocampus in a dose-dependent manner. Pressive Ang II induced specific changes in microglial morphology, indicating differences in functional phenotype. An increase in hippocampal glial fibrillary acidic protein (GFAP) was seen in mice receiving pressive Ang II, while no induction of cerebral gliosis was observed after 7 days of subpressive Ang II infusion. Although phenylephrine led to increased astrogliosis, it did not affect Iba-1 expression. Pressive Ang II stimulated TNF-α production in the hippocampus, and daily treatment with hydralazine prevented this increase. Hydralazine also reduced GFAP and Iba-1 levels. With longer perfusion (14 days), subpressive Ang II led to some but not all the inflammatory changes detected with the pressive doses, mainly an increase in CD68 and Iba-1 but not of GFAP or TNF-α.

Conclusions

Blood pressure and Ang II differentially contribute to hippocampal inflammation in mice. Control of blood pressure and Ang II levels should prevent or reduce brain inflammation and therefore brain dysfunctions associated with hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1090-z) contains supplementary material, which is available to authorized users.

Circulating angiopoietin-2 and its soluble receptor Tie-2 concentrations are related to inflammatory markers in the general population

BACKGROUND

The Angiopoietin/Tie (Tyrosine kinase with Ig and EGF homology domains) signaling axis has crucial influences on angiogenesis and the vasculature's reorganization. Moreover, angiopoietin-2 (Ang2) is discussed as a biomarker for diseases' severity and development. Previous studies reported increased Ang2 levels in patients with inflammatory diseases and associations of Ang2 with inflammation markers in relatively small samples. We aimed to assess the relation of Ang2 and Tie2 with inflammation markers in the general population.

METHODS AND RESULTS

Data of 6624 participants of the population-based Study of Health in Pomerania (SHIP-1) and the independent SHIP-Trend were used. Ang2, Tie2 and inflammatory biomarkers, including fibrinogen, high-sensitive C-reactive protein (hsCRP) and white blood cell count (WBC), were measured. Adjusted analysis of variance (ANOVA) and linear/logistic regression models were performed in the entire sample and in individuals free of hypertension and diabetes. ANOVA [adjusted means of the 1st vs. 4th Ang2 quartile: fibrinogen 3.0 vs. 3.2 g/l; hsCRP 1.2 vs. 1.6 mg/l; WBC 5.9 vs. 6.6 Gpt/l] and regression models adjusted for potential confounders revealed positive relations of Ang2 with all considered inflammation markers. These associations persisted after the exclusion of individuals with hypertension and diabetes. In contrast, Tie2 showed no clear association pattern with the investigated inflammatory markers even if a trend toward a positive relation with fibrinogen became apparent.

CONCLUSION

Ang2 was positively associated with fibrinogen, hsCRP and WBC in a large population-based setting. These findings partly agree with previous results, largely obtained in clinical samples. Ang2 has diverse postulated effects on inflammation processes, like increase of vascular leakage or influences on the adhesion of leukocytes to the vessel wall. The proinflammatory character of these effects is similar to these of fibrinogen which conforms to our findings of relations between the markers. However, further research is needed to elucidate possible functional mechanisms.