Immune mechanisms in hypertension and vascular injury

Toll-like receptor 9 contributes to perivascular adipose tissue dysfunction in spontaneously hypertensive rats

Perivascular adipose tissue (PVAT) plays a key role in vascular homeostasis by exerting anticontractile effects. However, PVAT dysfunction in hypertension contributes to vascular abnormalities via inflammation and oxidative stress. This study investigates the role of Toll-like receptor 9 (TLR9) in PVAT dysfunction in spontaneously hypertensive rats (SHR). Elevated TLR9 expression and activation were observed in SHR PVAT, along with increased pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and reactive oxygen species (ROS). These changes impaired PVAT's anticontractile effects, reduced nitric oxide (NO) bioavailability, and heightened vascular contraction. Pharmacological inhibition of TLR9 with ODN2088 restored PVAT's anticontractile function, reduced inflammation and oxidative stress, and improved vascular tone. This treatment also significantly lowered systolic blood pressure in SHR. TLR9-mediated PVAT dysfunction was closely linked to NF-κB signaling, as inhibition of this pathway attenuated inflammatory cytokine production and improved vascular reactivity. ROS scavenging with Tiron confirmed the role of oxidative stress in the loss of PVAT function. Despite unaltered endothelial nitric oxide synthase (eNOS) expression, NO levels were reduced in SHR PVAT due to ROS-induced scavenging. Notably, TLR9 inhibition restored NO bioavailability, reinforcing its therapeutic potential. These findings establish TLR9 as a critical mediator of PVAT dysfunction in hypertension, driving inflammation, oxidative stress, and vascular impairment. Targeting TLR9 and oxidative stress may represent effective therapeutic strategies for mitigating vascular dysfunction in hypertension.

The Role of Immune Cells in Moyamoya Disease

Moyamoya disease (MMD) is a rare progressive cerebrovascular disorder characterized by the stenosis or occlusion of the terminal segments of the internal carotid arteries, leading to the development of abnormal collateral vascular networks. These networks are a compensatory mechanism for reduced blood flow to the brain. Despite extensive research, the exact etiology of MMD remains unknown, although recent studies suggest that immune system dysfunction plays a critical role in its pathogenesis. In particular, the involvement of immune cells such as T cells, macrophages, and dendritic cells has been increasingly recognized. These immune cells contribute to the inflammatory process and vascular remodeling observed in MMD patients, further complicating the disease's progression. Inflammation and immune-mediated damage to the vessel walls may accelerate the narrowing and occlusion of arteries, exacerbating ischemic events in the brain. Additionally, studies have revealed that certain genetic and environmental factors can influence immune system activation in MMD, linking these pathways to disease development. This review aims to provide a comprehensive overview of the immune mechanisms at play in MMD, focusing on how immune cells participate in vascular injury and remodeling. Understanding these immunological processes may offer new therapeutic targets to halt or reverse disease progression, potentially leading to more effective treatment strategies for MMD.

Muscular Performance and Blood Pressure After Different Pre-Strength Training Strategies in Recreationally Strength-Trained Women: Cross-Over Trial

BACKGROUND

This study aimed to investigate the acute effects of different pre-ST strategies on muscular performance and blood pressure (BP) responses in recreationally strength-trained women.

METHODS

Twelve overweight women with normal BP were recruited and performed six experimental protocols in a randomized order: (1) control protocol (CC), where BP was assessed without exercises performed; (2) ST; (3) foam rolling warm-up followed by ST (FR + ST); (4) specific warm-up followed by ST (SW + ST); (5) aerobic exercise followed by ST (AE + ST); and (6) stretching exercises followed by ST (SE + ST). ST consisted of three sets at 80% of 10 repetition maximum with a self-suggested rest interval between sets for bench press, back squat, bench press 45°, front squat, lat pull-down, leg press, shoulder press, and leg extension.

RESULTS

All experimental protocol had a lower total training volume, fatigue index, and repetitions performance in relation to ST (p < 0.05). No significant reduction was observed in systolic and diastolic BP for any protocol or exercise, although the effect size magnitudes ranged from trivial to large. Decreases in maximum repetitions, resistance to fatigue, and total training volume were performed before ST as warm-up strategies. However, these strategies indicated a clinical reduction in BP with a large and meaningful magnitude (effect size) in recreationally strength-trained women with normal to elevated BP.

CONCLUSIONS

The results of this investigation may help to influence decision-making by practitioners who desire to elicit a post-exercise hypotension response in both subjects with normal BP and hypertension.

The gut-immune axis during hypertension and cardiovascular diseases

The gut-immune axis is a relatively novel phenomenon that provides mechanistic links between the gut microbiome and the immune system. A growing body of evidence supports it is key in how the gut microbiome contributes to several diseases, including hypertension and cardiovascular diseases (CVDs). Evidence over the past decade supports a causal link of the gut microbiome in hypertension and its complications, including myocardial infarction, atherosclerosis, heart failure, and stroke. Perturbations in gut homeostasis such as dysbiosis (i.e., alterations in gut microbial composition) may trigger immune responses that lead to chronic low-grade inflammation and, ultimately, the development and progression of these conditions. This is unsurprising, as the gut harbors one of the largest numbers of immune cells in the body, yet is a phenomenon not entirely understood in the context of cardiometabolic disorders. In this review, we discuss the role of the gut microbiome, the immune system, and inflammation in the context of hypertension and CVD, and consolidate current evidence of this complex interplay, whilst highlighting gaps in the literature. We focus on diet as one of the major modulators of the gut microbiota, and explain key microbial-derived metabolites (e.g., short-chain fatty acids, trimethylamine N-oxide) as potential mediators of the communication between the gut and peripheral organs such as the heart, arteries, kidneys, and the brain via the immune system. Finally, we explore the dual role of both the gut microbiome and the immune system, and how they work together to not only contribute, but also mitigate hypertension and CVD.

Role of Treg cell subsets in cardiovascular disease pathogenesis and potential therapeutic targets

In the genesis and progression of cardiovascular diseases involving both innate and adaptive immune responses, inflammation plays a pivotal and dual role. Studies in experimental animals indicate that certain immune responses are protective, while others exacerbate the disease. T-helper (Th) 1 cell immune responses are recognized as key drivers of inflammatory progression in cardiovascular diseases. Consequently, the CD4+CD25+FOXP3+ regulatory T cells (Tregs) are gaining increasing attention for their roles in inflammation and immune regulation. Given the critical role of Tregs in maintaining immune-inflammatory balance and homeostasis, abnormalities in their generation or function might lead to aberrant immune responses, thereby initiating pathological changes. Numerous preclinical studies and clinical trials have unveiled the central role of Tregs in cardiovascular diseases, such as atherosclerosis. Here, we review the roles and mechanisms of Treg subsets in cardiovascular conditions like atherosclerosis, hypertension, myocardial infarction and remodeling, myocarditis, dilated cardiomyopathy, and heart failure. While the precise molecular mechanisms of Tregs in cardiac protection remain elusive, therapeutic strategies targeting Tregs present a promising new direction for the prevention and treatment of cardiovascular diseases.

Systemic Inflammation Response Index as a Predictor of Stroke Risk in Elderly Patients with Hypertension: A Cohort Study

Objective

This study aimed to evaluate the relationship between the systemic inflammation response index (SIRI) and the risk of stroke and its subtypes in elderly patients with hypertension and to explore its predictive accuracy and any potential effect modifiers.

Methods

The study included 4749 participants with no history of stroke at baseline. Cox regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CIs). Interaction tests and subgroup analyses were conducted. The predictive performance of various inflammatory indicators for stroke was compared using the area under the curve (AUC), continuous net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

Results

During a median follow-up period of 3.2 years, 640 strokes were recorded, of which 526 were ischemic and the remainder hemorrhagic. After adjustment for confounders, compared to the reference group, the HRs (95% CI) of stroke were 1.28 (95% CI, 1.01-1.64) and 1.46 (95% CI, 1.14-1.88) for participants in the second and third tertiles, respectively. We observed interactions between SIRI and homocysteine levels (< 15 vs. ≥ 15 μmol/L) (p for interaction = 0.014) on ischemic stroke risk. Furthermore, the AUC, NRI, and IDI analyses demonstrated that SIRI exhibited better predictive value for stroke risk when compared to other indicators. Similar results were observed for both ischemic and hemorrhagic strokes.

Conclusion

Elevated SIRI levels were significantly associated with the risk of stroke and its subtypes in elderly patients with hypertension, suggesting its potential as a promising indicator for stroke risk in this population. However, larger prospective studies are needed to confirm these findings.

Role of the Gut Microbiome in the Development of Atherosclerotic Cardiovascular Disease

Atherosclerotic cardiovascular disease (ASCVD) is the primary cause of death globally, with nine million deaths directly attributable to ischemic heart diseases in 2020. Since the last few decades, great effort has been put toward primary and secondary prevention strategies through identification and treatment of major cardiovascular risk factors, including hypertension, diabetes, dyslipidemia, smoking, and a sedentary lifestyle. Once labelled “the forgotten organ”, the gut microbiota has recently been rediscovered and has been found to play key functions in the incidence of ASCVD both directly by contributing to the development of atherosclerosis and indirectly by playing a part in the occurrence of fundamental cardiovascular risk factors. Essential gut metabolites, such as trimethylamine N-oxide (TMAO), secondary bile acids, lipopolysaccharides (LPS), and short-chain fatty acids (SCFAs), have been associated with the extent of ischemic heart diseases. This paper reviews the latest data on the impact of the gut microbiome in the incidence of ASCVD.

The Increased Risk of Hypertension Caused by Irrational Dietary Pattern May Be Associated with Th17 Cell in the Middle-Aged and Elderly Rural Residents of Beijing City, Northern China: A 1:1 Matched Case-Control Study

An irrational diet has been widely considered as one of the vital risk factors of hypertension. Previous studies have indicated that immune dysfunction may be involved in the pathogenic process of hypertension, while fewer studies have mentioned whether CD4+ T cells are involved in the association between dietary pattern and hypertension. This present 1:1 matched case-control study was conducted to analyze the association among dietary pattern, CD4+ T cells and hypertension. A total of 56 patients with diagnosed hypertension and 56 subjects without diagnosed hypertension in the rural area of Beijing City, northern China, were matched by age and gender, and then classified into a case group and a control group, respectively. Compared with the control group, higher frequencies of pro-inflammatory CD4+ T cells, such as Th1, Th1(IFN-γ), Th17(IL-17A), and Th1/17 (IFN-γ/IL-17A), were found in the case group (p < 0.05). A significantly higher level of circulating IL-17A was also found in the case group (7.4 pg/mL vs. 8.2 pg/mL, p < 0.05). Five dietary patterns were identified using exploratory factor analysis. An irrational dietary pattern, characterized by high-factor loadings of refined wheat (0.65), meat (0.78), poultry (0.76), and alcoholic beverage (0.73), was positively associated with SBP (β = 5.38, 95%CI = 0.73~10.03, p < 0.05) in the multiple linear regression model with the adjustment of potential covariates. The other dietary patterns showed no significant association with blood pressure. Furthermore, meat, processed meat, and animal viscera were positively correlated with the peripheral Th17 or Th1/17. In conclusion, the irrational dietary pattern characterized by refined wheat, meat, poultry, and alcoholic beverage, was positively correlated with blood pressure, and may increase the risk of hypertension in the rural area of Beijing, northern China. Th17, a subset of the CD4+ T helper cells, may be involved in the association between irrational dietary pattern and hypertension.

Peripheral Immune Cell Composition is Altered in Women Before and After a Hypertension Diagnosis

BACKGROUND

The development and consequences of hypertension involve multiple biological systems that may include changes in immune profiles. Whether hypertension is related to peripheral immune cell composition has not been examined in large human cohorts.

METHODS

We estimated circulating proportions of 12 leukocyte subsets from the lymphoid and myeloid lineages by deconvolving cell-type-specific DNA methylation data from 4124 women. Hypertension status at baseline was defined by current use of antihypertensive medication and blood pressure measurements while new incident cases were identified during follow-up via annual health questionnaires.

RESULTS

Among hypertension-free women at baseline, higher B cell and lower naïve CD4+ helper T cell proportions were associated with subsequent increased hazard of hypertension incidence (B cells; adjusted HR: 1.17 [95% CI: 1.02-1.35]; P=0.03; naïve CD4+ T cell, adjusted HR: 0.88 [95% CI: 0.78-0.99]; P=0.04). Blood pressure measurements at baseline were similarly positively associated with B cells and inversely associated with naïve CD4+ helper T cells. Compared to normotensive women, women with hypertension had higher circulating proportions of neutrophils (adjusted odds ratio: 1.18 [95% CI: 1.07-1.31]; P=0.001) and lower proportions of CD4+ helper T cells (adjusted odds ratio: 0.90 [95% CI: 0.81-1.00] P=0.05), natural killers (adjusted odds ratio: 0.82 [95% CI: 0.74-0.91]; P<0.001), and B cells (adjusted odds ratio: 0.84 [95% CI: 0.74-0.96]; P=0.01).

CONCLUSIONS

These observations suggest that shifts in lymphocyte subsets occur before hypertension development, followed by later changes to neutrophils and additional lymphocytes.

Dietary Influences on Gut Microbiota with a Focus on Metabolic Syndrome

There is a clear correlation between gut microbiota, diet, and metabolic outcomes. A diet high in fiber has been shown to decrease inflammation, increase insulin sensitivity, and reduce dyslipidemias whereas a diet high in fat and sugar leads to dyslipidemia, insulin resistance, and low-grade inflammation. There is recent evidence suggesting that the human gut microbiota has a significant role in the development or the resolution of metabolic syndrome (MetS) and associated conditions. Leading a stressful, sedentary lifestyle with limited or no physical activity and consuming an unhealthy diet high in saturated fat, simple carbohydrates, and sodium and low in dietary fiber and in high-quality protein are some of the contributing factors. Unhealthy diets have been shown to induce alterations in the gut microbiota and contribute to the pathogenesis of MetS by altering microbiota composition and disrupting the intestinal barrier, which leads to low-grade systemic inflammation. In contrast, healthy diets can lead to changes in microbiota that increase gut barrier function and increase the production of anti-inflammatory biomarkers. This review aims at providing a more in-depth discussion of diet-induced dysbiosis of the gut microbiota and its effect on MetS. Here, we discuss the possible mechanisms involved in the development of the metabolic biomarkers that define MetS, with an emphasis on the role of sugar and dietary fiber in microbiome-mediated changes in low-grade systemic inflammation and metabolic dysfunction.

Effects of Manual Therapies and Resistance Exercise on Postexercise Hypotension in Women With Normal Blood Pressure

ABSTRACT

Monteiro, ER, Pescatello, LS, Winchester, JB, Corrêa Neto, VG, Brown, AF, Budde, H, Marchetti, PH, Silva, JG, Vianna, JM, and Novaes, JdS. Effects of manual therapies and resistance exercise on postexercise hypotension in women with normal blood pressure. J Strength Cond Res 36(4): 948-954, 2022-The purpose of this investigation was to examine the acute effects of resistance exercise (RE) and different manual therapies (static stretching and manual massage [MM]) performed separately or combined on blood pressure (BP) responses during recovery in women with normal BP. Sixteen recreationally strength-trained women (age: 25.1 ± 2.9 years; height: 158.9 ± 4.1 cm; body mass: 59.5 ± 4.9 kg; body mass index: 23.5 ± 1.9 kg·m-2; baseline systolic BP median: 128 mm Hg; and baseline diastolic BP median: 78 mm Hg) were recruited. All subjects performed 6 experiments in a randomized order: (a) rest control (CON), (b) RE only (RE), (c) static-stretching exercise only (SS), (d) MM only, (e) RE immediately followed by SS (RE + SS), and (f) RE immediately followed by MM (RE + MM). RE consisted of 3 sets of bilateral bench press, back squat, front pull-down, and leg press exercises at 80% of 10RM. Static stretching and MM were applied unilaterally in 2 sets of 120 seconds to each of the quadriceps, hamstring, and calf regions. Systolic (SBP) and diastolic BP were measured before (rest) and every 10 minutes for 60 minutes following (Post 10-60) each intervention. There were significant intragroup differences for RE in Post-50 (p = 0.038; d = -2.24; ∆ = -4.0 mm Hg). Similarly, SBP intragroup differences were found for the SS protocol in Post-50 (p = 0.021; d = -2.67; ∆ = -5.0 mm Hg) and Post-60 (p = 0.008; d = -2.88; ∆ = -5.0 mm Hg). Still, SBP intragroup differences were found for the MM protocol in Post-50 (p = 0.011; d = -2.61; ∆ = -4.0 mm Hg) and Post-60 (p = 0.011; d = -2.74; ∆ = -4.0 mm Hg). Finally, a single SBP intragroup difference was found for the RE + SS protocol in Post-60 (p = 0.024; d = -3.12; ∆ = -5.0 mm Hg). Practitioners should be aware that SS and MM have the potential to influence BP responses in addition to RE or by themselves and therefore should be taken into consideration for persons who are hypertensive or hypotensive.

Immune System and Microvascular Remodeling in Humans

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

Putative regulatory functions of SNPs associated with bronchial asthma, arterial hypertension and their comorbid phenotype

Linkage disequilibrium (LD) of single nucleotide polymorphisms (SNPs) of TLR4/AL160272.2 (rs1927914, rs1928298, rs7038716, rs7026297, rs7025144) was estimated in the Slavs of West Siberia. We further investigated an association of SNPs in TLR4/AL160272.2 (rs1927914, rs7038716, rs7025144), SERPINA1 (rs1980616), ATXN2/BRAP (rs11065987), IL2RB (rs2284033), NT5C2 (rs11191582), CARD8 (rs11669386), ANG/RNASE4 (rs1010461), and ABTB2/ САТ (rs2022318) genes with bronchial asthma (BA), arterial hypertension (AH) and their comorbidity. Then, the disease-associated SNPs were annotated in silico in relation to their potential regulatory functions. Strong LD was detected between rs1928298 and rs1927914, as well as rs7026297 and rs7038716 in the Slavs of West Siberia. It was found that the rs1927914 G allele of the TLR4 gene and the rs1980616 C allele of the SERPINA1 gene are associated with the predisposition to BA. These SNPs can affect binding affinity of transcription factors of the Pou and Klf4 families, as well as the expression levels of the TLR4 and SERPINA1 genes. The rs11065987 allele A of the ATXN2/BRAP genes, the rs11669386 A allele of the CARD8 gene, the rs2284033 allele G of the IL2RB gene, and the rs11191582 allele G of the NT5C2 gene were associated with the risk of AH. These variants can alter binding affinity of the Hoxa9, Irf, RORalpha1 and HMG-IY transcription factors, as well as the expression levels of the ALDH2, CARD8, NT5C2, ARL3, and SFXN2 genes in blood cells/vessels/heart, respectively. The risk of developing a comorbid phenotype of AD and AH is associated with the A allele of rs7038716 and the T allele of rs7025144 of the TLR4/AL160272.2 genes, the A allele of rs1010461 of the ANG gene and the C allele of rs2022318 of the ABTB2/CAT genes. Variants rs7038716 and rs7025144 can change the expression levels of the TLR4 gene in blood cells, while rs1010461 and rs2022318 influence the expression levels of the ANG and RNASE4 genes as well as the CAT and ABTB2 genes in blood cells, lungs/vessels/heart.

Inflammatory Basis of Atherosclerosis: Modulation by Sex Hormones

Atherosclerosis-related cardiovascular diseases (CVDs) are the leading cause of death globally. Several lines of evidence are supportive of the contributory role of vascular inflammation in atherosclerosis. Diverse immune cell types, including monocytes/macrophages, T-cells and neutrophils, as well as specialized proresolving lipid mediators, have been successfully characterized as key players in vascular inflammation. The increased prevalence of atherosclerotic CVD in men in comparison to age-matched premenopausal women and the abolition of sex differences in prevalence during menopause strongly suggest a pivotal role of sex hormones in the development of CVD. Indeed, many animal and human studies conclusively implicate sex hormones as a crucial component in driving the immune response. This is further corroborated by the effective identification of sex hormone receptors in vascular endothelial cells, vascular smooth muscle cells and immune cells. Collectively, these findings suggest a cellular communication between sex hormones and vascular or immune cells underlying the vascular inflammation in atherosclerosis. The aim of this review is to provide an overview of vascular inflammation as a causal cue underlying atherosclerotic CVDs within the context of the modulatory effects of sex hormones. Moreover, the cellular and molecular signaling pathways underlying the sex hormones- immune system interactions as potential culprits for vascular inflammation are highlighted with detailed and critical discussion. Finally, the review concludes by speculations on the potential sex-related efficacy of currently available immunotherapies in mitigating vascular inflammation. Conceivably, a deeper understanding of the immunoregulatory influence of sex hormones on vascular inflammation-mediated atherosclerosis permits sex-based management of atherosclerosis-related CVDs.

Inflammatory bowel disease and psoriasis: modernizing the multidisciplinary approach

Psoriasis and inflammatory bowel disease (IBD) are immune-mediated diseases occurring in barrier organs whose main task is to protect the organism from attack. These disorders are highly prevalent especially in northern Europe where psoriasis has a prevalence of around 3-4% and IBD around 0.3%. The prevalence of IBD in North America has been estimated at around 0.4%. The total incidence rates in northern Europe have been estimated at around 6 for Crohn's disease and 11 for ulcerative colitis per 100 000 person-years, compared with an incidence rate of around 280 per 100 000 person-years for psoriasis. Both diseases are less common in countries with a lower index of development. The rise in IBD appears to occur as populations adopt a westernized lifestyle, whereas psoriasis seems more stable and prevalence differences may derive more from variation in genetic susceptibility. The gut microbiota is clearly an important driver of IBD pathogenesis; in psoriasis, changes in gut and skin microbiota have been reported, but it is less clear whether and how these changes contribute to the pathogenesis. Large studies show that most identified genes are involved in the immune system. However, psoriasis and IBD are highly heterogeneous diseases and there is a need for more precise and deeper phenotyping to identify specific subgroups and their genetic, epigenetic and molecular signatures. Epigenetic modifications of DNA such as histone modifications, noncoding RNA effects on transcription and translation and DNA methylation are increasingly recognized as the mechanism underpinning much of the gene-environment interaction in the pathogenesis of both IBD and psoriasis. Our understanding of underlying pathogenetic mechanisms has deepened fundamentally over the past decades developing hand in hand with novel therapies targeting pathways and proinflammatory cytokines incriminated in disease. There is not only substantial overlap between psoriasis and IBD, but also there are differences with implication for therapy. In psoriasis, drugs targeting interleukin-23 and interleukin-17 have shown superior efficacy compared with anti-TNFs, whilst in IBD, drugs targeting interleukin-17 may be less beneficial. The therapeutic toolbox for psoriasis is impressive and is enlarging also for IBD. Still, there are unmet needs reflecting the heterogeneity of both diseases and there is a need for closer molecular diagnostics to allow for the development of precise therapeutics.

Vascular consequences of inflammation: a position statement from the ESH Working Group on Vascular Structure and Function and the ARTERY Society

: Inflammation is a physiological response to aggression of pathogenic agents aimed at eliminating the aggressor agent and promoting healing. Excessive inflammation, however, may contribute to tissue damage and an alteration of arterial structure and function. Increased arterial stiffness is a well recognized cardiovascular risk factor independent of blood pressure levels and an intermediate endpoint for cardiovascular events. In the present review, we discuss immune-mediated mechanisms by which inflammation can influence arterial physiology and lead to vascular dysfunction such as atherosclerosis and arterial stiffening. We also show that acute inflammation predisposes the vasculature to arterial dysfunction and stiffening, and alteration of endothelial function and that chronic inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease and psoriasis are accompanied by profound arterial dysfunction which is proportional to the severity of inflammation. Current findings suggest that treatment of inflammation by targeted drugs leads to regression of arterial dysfunction. There is hope that these treatments will improve outcomes for patients.

Parental PM2 .5 exposure changes Th17/Treg cells in offspring, is associated with the elevation of blood pressure

Epidemiological evidences have indicated that fine particulate matter (PM_2.5 ) exposure is associated with the occurrence and development of hypertension. The present study aims to explore the effects of parental PM_2.5 exposure on blood pressure in offspring and elucidate the potential mechanism. The parental male and female C57BL/6 mice were exposed to concentrated PM_2.5 or filtered air (FA) using Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) for 16 weeks. At week 12, the mice were assigned to breed offspring. The male offspring mice were further exposed to PM_2.5 or FA as above method. During the parental exposure, the average PM_2.5 concentration was 133.7 ± 53.32 μg/m³ in PM chamber, whereas the average concentration in FA chamber was 9.4 ± 0.23 μg/m³ . Similarly, during the offspring exposure, the average concentration in PM and FA chamber were 100.76 ± 26.97 μg/m³ and 9.15 ± 0.15 μg/m³ , respectively. The PM_2.5 -exposed offspring mice displayed the elevation of blood pressure, the increase of angiotensin II (Ang II), the decrease of angiotensin converting enzyme 2 (ACE2) and Ang (1-7) in serum when compared with the FA-exposed offspring mice. The similar results displayed in the proteins expression of ACE2, AT1R, and Ang (1-7) in vessel and kidney. More importantly, parental PM exposure further induced the increase in serous Ang II and the protein expression of AT1R in vessel, but decrease in ACE2 and Ang (1-7). The serous Ang II was positively associated with splenic T helper type 17 (Th17) cell population and serous IL (interleukin)-17A, but negatively associated with T regular (Treg) cell population and serous IL-10. The results suggested that parental air pollution exposure might induce the elevation of offspring blood pressure via mediate Th17- and Treg-related immune microenvironment.

Does taking an angiotensin inhibitor increase the risk for COVID-19? - a systematic review and meta-analysis

Because SARS-COV2 entry into cells is dependent on angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) increase ACE2 activity, the safety of ACEI/ARB usage during the coronavirus disease 2019 (COVID-19) pandemic is a controversial topic. To address that issue, we performed a meta-analysis following The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Searches of the Embase, MEDLINE, PubMed, and Cochrane Library databases identified 16 case-control studies examining the effect of ACEI/ARB on the incidence of COVID-19 and its severity. ACEI/ARB usage was associated with an increased risk of COVID-19 morbidity (odds ratio (OR) 1.20, 95% confidence interval (CI) 1.07-1.33, P=0.001) among the general population but not in a hypertensive population (OR 1.05, 95% CI 0.90-1.21, P=0.553). ACEI/ARB usage was not associated with an increased risk of COVID-19 morbidity (coefficient 1.00, 95% CI 1.00-1.00, P=0.660) when we adjusted for hypertension in the general population. ACEI/ARB usage was also not associated with an increased risk of severe illness (OR 0.90, 95%CI 0.55-1.47, P=0.664) or mortality (OR 1.43, 95%CI 0.97-2.10, P=0.070) in COVID-19 patients. Our meta-analysis revealed that ACEI/ARB usage was not associated with either the increased risk of SARS-COV2 infection or the adverse outcomes in COVID-19 patients.

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)..

COVID-19 and Microvascular Disease: Pathophysiology of SARS-CoV-2 Infection With Focus on the Renin-Angiotensin System

The recently described severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people, with thousands of fatalities. It has prompted global efforts in research, with focus on the pathophysiology of coronavirus disease-19 (COVID-19), and a rapid surge of publications. COVID-19 has been associated with a myriad of clinical manifestations, including the lungs, heart, kidneys, central nervous system, gastrointestinal system, skin, and blood coagulation abnormalities. The endothelium plays a key role in organ dysfunction associated with severe infection, and current data suggest that it is also involved in SARS-CoV-2-induced sepsis. This critical review aimed to address a possible unifying mechanism underlying the diverse complications of COVID-19: microvascular dysfunction, with emphasis on the renin-angiotensin system. In addition, research perspectives are suggested in order to expand understanding of the pathophysiology of the infection.

Metabolic Syndrome and COVID 19: Endocrine-Immune-Vascular Interactions Shapes Clinical Course

The ongoing coronavirus disease 2019 (COVID-19) pandemic is caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Individuals with metabolic syndrome are at increased risk for poor disease outcomes and mortality from COVID-19. The pathophysiologic mechanisms for these observations have not been fully elucidated. A critical interaction between SARS-CoV-2 and the angiotensin-converting enzyme 2 (ACE2) facilitates viral entry into the host cell. ACE2 is expressed in pancreatic islets, vascular endothelium, and adipose tissue, and the SARS-CoV-2 -ACE2 interaction in these tissues, along with other factors, governs the spectrum and the severity of clinical manifestations among COVID-19 patients with metabolic syndrome. Moreover, the pro-inflammatory milieu observed in patients with metabolic syndrome may contribute toward COVID-19-mediated host immune dysregulation, including suboptimal immune responses, hyperinflammation, microvascular dysfunction, and thrombosis. This review describes the spectrum of clinical features, the likely pathophysiologic mechanisms, and potential implications for the management of metabolic syndrome in COVID-19 patients.

Angiotensin II and leukocyte trafficking: New insights for an old vascular mediator. Role of redox-signaling pathways

Inflammation and activation of the immune system are key molecular and cellular events in the pathogenesis of cardiovascular diseases, including atherosclerosis, hypertension-induced target-organ damage, and abdominal aortic aneurysm. Angiotensin II (Ang-II) is the main effector peptide hormone of the renin-angiotensin system. Beyond its role as a potent vasoconstrictor and regulator of blood pressure and fluid homeostasis, Ang-II is intimately involved in the development of vascular lesions in cardiovascular diseases through the activation of different immune cells. The migration of leukocytes from circulation to the arterial subendothelial space is a crucial immune response in lesion development that is mediated through a sequential and coordinated cascade of leukocyte-endothelial cell adhesive interactions involving an array of cell adhesion molecules present on target leukocytes and endothelial cells and the generation and release of chemoattractants that activate and guide leukocytes to sites of emigration. In this review, we outline the key events of Ang-II participation in the leukocyte recruitment cascade, the underlying mechanisms implicated, and the corresponding redox-signaling pathways. We also address the use of inhibitor drugs targeting the effects of Ang-II in the context of leukocyte infiltration in these cardiovascular pathologies, and examine the clinical data supporting the relevance of blocking Ang-II-induced vascular inflammation.

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

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

Circulating Sestrin Levels Are Increased in Hypertension Patients

Background

Sestrins (Sesns), a group of oxidative stress-related proteins, have been reported to be involved in various cardiovascular diseases, including aortic dissection and chronic heart failure. This study is aimed at investigating the level of circulating Sesn1, Sesn2, and Sesn3 in hypertension patients.

Methods

Plasma levels of Sesn1, Sesn2, and Sesn3 in 400 hypertensive patients and 100 normotensive subjects were detected using enzyme-linked immunosorbent assay (ELISA) kits. The hypertension patients were divided into groups with grade I (n = 140), grade II (n = 180), and grade III (n = 80) hypertension.

Results

Compared with the normotensive subjects, Sesn1, Sesn2, and Sesn3 levels were increased in patients with hypertension, with a gradual increase between the groups with grade I, grade II, and grade III hypertension. Elevated Sesn1, Sesn2, and Sesn3 levels were positively correlated with both the systolic blood pressure (SBP) and diastolic blood pressure (DBP). Moreover, Sesn1, Sesn2, and Sesn3 levels were elevated in patients with dipper hypertension and further increased in patients with nondipper hypertension. In addition, smokers, as well as patients with higher levels of angiotensin II (Ang II) and carotid atherosclerotic plaque (CAP), exhibited increased Sesn1, Sesn2, and Sesn3 levels when compared with patients without these clinical characteristics. Furthermore, plasma levels of Sesn1, Sesn2, and Sesn3 were negatively correlated with the presence of CAP.

Conclusions

Circulating Sesn levels are increased in patients with hypertension and may be a target for the prevention and treatment of clinical hypertension.

Nuclear Activation Function 2 Estrogen Receptor α Attenuates Arterial and Renal Alterations Due to Aging and Hypertension in Female Mice

Background

The cardiovascular protective effects of estrogens in premenopausal women depend mainly on estrogen receptor α (ERα). ERα activates nuclear gene transcription regulation and membrane‐initiated signaling. The latter plays a key role in estrogen‐dependent activation of endothelial NO synthase. The goal of the present work was to determine the respective roles of the 2 ERα activities in endothelial function and cardiac and kidney damage in young and old female mice with hypertension, which is a major risk factor in postmenopausal women.

Methods and Results

Five‐ and 18‐month‐old female mice lacking either ERα (ERα^−/−), the nuclear activating function AF2 of ERα (AF2°), or membrane‐located ERα (C451A) were treated with angiotensin II (0.5 mg/kg per day) for 1 month. Systolic blood pressure, left ventricle weight, vascular reactivity, and kidney function were then assessed. Angiotensin II increased systolic blood pressure, ventricle weight, and vascular contractility in ERα^−/− and AF2° mice more than in wild‐type and C451A mice, independent of age. In both the aorta and mesenteric resistance arteries, angiotensin II and aging reduced endothelium‐dependent relaxation in all groups, but this effect was more pronounced in ERα^−/− and AF2° than in the wild‐type and C451A mice. Kidney inflammation and oxidative stress, as well as blood urea and creatinine levels, were also more pronounced in old hypertensive ERα^−/− and AF2° than in old hypertensive wild‐type and C451A mice.

Conclusions

The nuclear ERα‐AF2 dependent function attenuates angiotensin II–dependent hypertension and protects target organs in aging mice, whereas membrane ERα signaling does not seem to play a role.

Pre-Eclampsia: Microbiota possibly playing a role

Pre-eclampsia (PE) is a complication of pregnancy that is associated with mortality and morbidity in mothers and fetuses worldwide. Oxygen dysregulation in the placenta, abnormal remodeling of the spiral artery, defective placentation, oxidative stress at the fetal-maternal border, inflammation and angiogenic impairment in the maternal circulation are the main causes of this syndrome. These events result in a systemic and diffuse endothelial cell dysfunction, an essential pathophysiological feature of PE. The impact of bacteria on the multifactorial pathway of PE is the recent focus of scientific inquiry since microbes may cause each of the aforementioned features. Microbes and their derivatives by producing antigens and other inflammatory factors may trigger infection and inflammatory responses. A mother's bacterial communities in the oral cavity, gut, vagina, cervix and uterine along with the placenta and amniotic fluid microbiota may be involved in the development of PE. Here, we review the mechanistic and pathogenic role of bacteria in the development of PE. Then, we highlight the impact of alterations in a set of maternal microbiota (dysbiosis) on the pathogenesis of PE.

Secreted Monocyte miR-27a, via Mesenteric Arterial Mas Receptor-eNOS Pathway, Causes Hypertension

BACKGROUND

Essential hypertension is associated with increased plasma concentrations of extracellular vesicles (EVs). We aimed to determine the role of monocyte miR-27a in EVs on arterial Mas receptor expression, and its involvement in the pathogenesis of hypertension.

METHODS

THP-1 cells were transfected with miR-27a mimic and miR-27a inhibitor, and EVs were collected. Mas receptor expression and endothelial nitric oxide synthase (eNOS) phosphorylation were determined by immunoblotting. Sprague-Dawley (SD) rats received EVs via tail-vein injection. Blood pressure (BP) was measured with the tail-cuff method. The vasodilatory response of mesenteric arteries was measured using a small vessel myograph.

RESULTS

EVs from THP-1 cells increased rat BP by impairing Ang-(1-7)-mediated vasodilation in mesenteric arteries, which was further exaggerated by EVs from lipopolysaccharides-treated THP-1 cells. As the receptor and key signaling of Ang-(1-7), next experiments found that Mas receptor expression and eNOS phosphorylation were decreased in mesenteric arteries from EVs-treated SD rats. Screening studies found miR-27a in EVs may be involved in this process. Through transfection with miR-27a inhibitor or miR-27a mimic, we found that miR-27a downregulates Mas receptor expression in endothelial cells. Injection of EVs from miR-27a-transfected HEK-293 cells decreased Mas receptor and eNOS phosphorylation in mesenteric arteries, impaired Ang-(1-7)-mediated vasodilation and increased BP. Earlier effects were reversed using cells with downregulation of miR-27 in EVs.

CONCLUSIONS

Monocyte miR-27a in EVs decreases Mas receptor expression and eNOS phosphorylation in endothelium, impairs Ang-(1-7)-mediated vasodilation, and causes hypertension. Understanding the contributions of EVs in the pathogenesis of hypertension may facilitate their use as a diagnostic biomarker.

Therapeutic Implications of Nitrite in Hypertension

Nitrite, an anion produced from the oxidative breakdown of nitric oxide (NO), has traditionally been viewed as an inert molecule. However, this dogma has been challenged with the findings that nitrite can be readily reduced to NO under pathological conditions, hence representing a physiologically relevant storage reservoir of NO either in the blood or tissues. Nitrite administration has been demonstrated to improve myocardial function in subjects with heart failure and to lower the blood pressure in hypertensive subjects. Thus, extensive amount of work has since been carried out to investigate the therapeutic potential of nitrite in treating cardiovascular diseases, especially hypertension. Studies done on several animal models of hypertension have demonstrated the efficacy of nitrite in preventing and ameliorating the pathological changes associated with the disease. This brief review of the current findings aims to re-evaluate the use of nitrite for the treatment of hypertension and in particular to highlight its role in improving endothelial function.

ADHD pathogenesis in the immune, endocrine and nervous systems of juvenile and maturating SHR and WKY rats

RATIONALE

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurobehavioural disorders with morphological and functional brain abnormalities. However, there is a growing body of evidence that abnormalities in the immune and endocrine systems may also account for the ADHD pathogenesis.

OBJECTIVES

To test ADHD pathogenesis in neurological, immune and endocrine systems, this study examined the concentrations of cytokines, chemokines, oxidative stress markers, metabolic parameters, steroid hormones and steroidogenic enzymes in the serum and/or tissues of spontaneously hypertensive rats (SHRs, animal model of ADHD) and Wistar Kyoto rats (WKYs, control animals). Moreover, the volume of the medial prefrontal cortex (mPFC) as well as the density of dopamine 2 (D2) receptor-expressing cells and tyrosine hydroxylase (TH)-positive nerve fibres in it was also elucidated.

METHODS

Peripheral blood, spleen and adrenal gland samples, as well as brain sections collected on day 35 (juvenile) and day 70 (maturating) from SHRs and WKYs, were processed by ELISA and immunohistochemistry, respectively.

RESULTS

The results show significant increases of serum and/or tissue concentrations of cytokines, chemokines and oxidative stress markers in juvenile SHRs when compared to the age-matched WKYs. These increases were accompanied by a lowered volume of the mPFC and up-regulation of D2 in this brain region. In maturating SHRs, the levels of inflammatory and oxidative stress markers were normalised and accompanied by elevated contents of steroid hormones.

CONCLUSIONS

Significant elevations of serum and/or tissue contents of cytokines, chemokines and oxidative stress markers as well as volumetric and neurochemical alterations in the mPFC of juvenile SHRs may suggest the cooperation of neurological and immune systems in the ADHD pathogenesis. Elevated levels of steroid hormones in maturating SHRs may be a compensatory effect involved in reducing inflammation and ADHD symptoms.

Current and emerging avenues for Alzheimer's disease drug targets

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

Nephropathy in Hypertensive Animals Is Linked to M2 Macrophages and Increased Expression of the YM1/Chi3l3 Protein

Macrophages contribute to a continuous increase in blood pressure and kidney damage in hypertension, but their polarization status and the underlying mechanisms have not been clarified. This study revealed an important role for M2 macrophages and the YM1/Chi3l3 protein in hypertensive nephropathy in a mouse model of hypertension. Bone marrow cells were isolated from the femurs and tibia of male FVB/N (control) and transgenic hypertensive animals that overexpressed the rat form of angiotensinogen (TGM(rAOGEN)123, TGM123-FVB/N). The cells were treated with murine M-CSF and subsequently with LPS+IFN-γ to promote their polarization into M1 macrophages and IL-4+IL-13 to trigger the M2 phenotype. We examined the kidneys of TGM123-FVB/N animals to assess macrophage polarization and end-organ damage. mRNA expression was evaluated using real-time PCR, and protein levels were assessed through ELISA, CBA, Western blot, and immunofluorescence. Histology confirmed high levels of renal collagen. Cells stimulated with LPS+IFN-γ in vitro showed no significant difference in the expression of CD86, an M1 marker, compared to cells from the controls or the hypertensive mice. When stimulated with IL-4+IL-13, however, macrophages of the hypertensive group showed a significant increase in CD206 expression, an M2 marker. The M2/M1 ratio reached 288%. Our results indicate that when stimulated in vitro, macrophages from hypertensive mice are predisposed toward polarization to an M2 phenotype. These data support results from the kidneys where we found an increased infiltration of macrophages predominantly polarized to M2 associated with high levels of YM1/Chi3l3 (91,89%), suggesting that YM1/Chi3l3 may be a biomarker of hypertensive nephropathy.

Sex, gut microbiome, and cardiovascular disease risk

Key differences exist between men and women in the determinants and manifestations of cardiovascular and cardiometabolic diseases. Recently, gut microbiome-host relations have been implicated in cardiovascular disease and associated metabolic conditions; therefore, gut microbiota may be key mediators or modulators driving the observed sexual dimorphism in disease onset and progression. While current evidence regarding pure physiological sex differences in gut microbiome composition is modest, robust research suggests that gut microbiome-dependent metabolites may interact with important biological pathways under sex hormone control, including toll-like receptor and flavin monooxygenase signaling. Here, we review key sex differences in gut microbiome interactions with four primary determinants of cardiovascular disease, impaired glucose regulation, dyslipidemia, hypertension, and obesity. Through this process, we propose important sex differences in downstream metabolic pathways that may be at the interface of the gut microbiome and cardiovascular disease.

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.

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.

β‑estradiol alleviates hypertension‑ and concanavalin A‑mediated inflammatory responses via modulation of connexins in peripheral blood lymphocytes

Gap junctions (GJs) formed by connexins (Cxs) in T lymphocytes have been reported to have important roles in the T lymphocyte-driven inflammatory response and hypertension-mediated inflammation. Estrogen has a protective effect on cardiovascular diseases, including hypertension and it attenuates excessive inflammatory responses in certain autoimmune diseases. However, the mechanisms involved in regulating the pro-inflammatory response are complex and poorly understood. The current study investigated whether β-estradiol suppresses hypertension and pro-inflammatory stimuli-mediated inflammatory responses by regulating Cxs and Cx-mediated GJs in peripheral blood lymphocytes. Male, 16-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) rats were randomly divided into the following three groups: WKY rats, vehicle (saline)-treated SHRs, and β-estradiol (20 µg/kg/day)-treated SHRs. β-estradiol was administered subcutaneously for 5 weeks. Hematoxylin and eosin staining was performed to evaluate target organ injury. Flow cytometry and ELISA were used to measure the populations of T lymphocyte subtypes in the peripheral blood, and expression of Cx40/Cx43 in T cell subtypes, and pro-inflammation cytokines levels, respectively. ELISA, a dye transfer technique, immunofluorescence and immunoblotting were used to analyze the effect of β-estradiol on pro-inflammatory cytokine secretion, Cx-mediated GJs and the expression of Cxs in concanavalin A (Con A)-stimulated peripheral blood lymphocytes isolated from WKY rat. β-estradiol significantly decreased blood pressure and inhibited hypertension-induced target organ injury in SHRs. Additionally, β-estradiol treatment significantly improved the immune homeostasis of SHRs, as demonstrated by the decreased percentage of cluster of differentiation (CD)4⁺/CD8⁺ T-cell subset ratio, reduced serum levels of pro-inflammatory cytokines and increased the percentage of CD4⁺CD25⁺ T cells. β-estradiol also markedly reduced the expression of Cx40/Cx43 in T lymphocytes from SHRs. In vitro, β-estradiol significantly suppressed the production of pro-inflammatory cytokines, reduced communication via Cx-mediated gap junctions and decreased the expression of Cx40/Cx43 in Con A-stimulated lymphocytes. These results indicate that β-estradiol attenuates inflammation and end organ damage in hypertension, which may be partially mediated via downregulated expression of Cxs and reduced function of Cx-mediated GJ.

Relationships Between Phenotype and Function of Blood CD4+ T-Cells and Ascending Thoracic Aortic Aneurysm: an Experimental Study

Introduction

Non-familial ascending thoracic aorta dilation and aneurysms (TAAs) are silent diseases in elderly patients. Histopathology revealed that functionally polarized infiltrating CD4⁺ T-cells play a key role in aortic wall weakening.

Objective

To evaluate the possible associations between phenotype and cytokine production of circulating CD4⁺ T-lymphocytes and the presence of TAA in patients with aortic valve disease (AVD).

Methods

We studied blood samples from 10 patients with TAA and 10 patients with AVD. Flow cytometry was used to quantify: a) CD4⁺ T-lymphocytes surface expression of CD25, CD28, and chemokine receptors (CCR5, CXCR3, CX3CR1); b) fractions of in vitro stimulated CD4⁺ T-cells producing cytokines (interferon gamma [IFN-γ], interleukin [IL]-17A, IL-21, IL-10); c) CD4⁺CD25^highFoxP3⁺ regulatory T-cells (Treg) fraction. Enzyme-linked immunosorbent assays (ELISA) were performed for cytokines (IFN-γ, IL-6, IL-10, IL-17A, IL-23, transforming growth factor beta [TGF-β]) and chemokines (RANTES, CX3CL1).

Results

The total CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells fraction was higher (P=0.0323) in AVD (20.452±4.673) than in TAA patients (8.633±2.030). The frequency ratio of CD4⁺ T-lymphocytes producing IFN-γ vs. IL-17A+IL-21 cytokine-producing CD4+ T-cells was higher (P=0.0239) in AVD (2.102±0.272) than in TAA (1.365±0.123) patients. The sum of CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells correlated positively with values of the previous cytokine ratio (P=0.0002, R=0.732). The ratio of CD4⁺CD28^±CD4⁺/CX3CR1⁺ T-cells vs. Treg was higher (P=0.0008) in AVD (20.859±3.393) than in TAA (6.367±1.277) patients.

Conclusion

Our results show that the presence of TAA in subjects with AVD is associated with imbalance between phenotypic and cytokine-producing subsets of circulating CD4+ T-lymphocytes, prevalently oriented towards a pro-fibrotic and IFN-γ counteracting effect to functional polarization.

NLRP3 Inflammasome Is Involved in Calcium-Sensing Receptor-Induced Aortic Remodeling in SHRs

Increasing evidence suggests that the NLRP3 (nucleotide oligomerization domain-like receptor family, pyrin domain containing 3) inflammasome participates in cardiovascular diseases. However, its role and activation mechanism during hypertension remains unclear. In this study, we tested the role and mechanism of calcium-sensing receptor (CaSR) in NLRP3 inflammasome activation during hypertension. We observed that the expressions of CaSR and NLRP3 were increased in spontaneous hypertensive rats (SHRs) along with aortic fibrosis. In vascular smooth muscle cells (VSMCs), the activation of NLRP3 inflammasome associated with CaSR and collagen synthesis was induced by angiotensin II (Ang II). Furthermore, inhibition of CaSR and NLRP3 inflammasome attenuated proinflammatory cytokine release, suggesting that CaSR-mediated activation of the NLRP3 inflammasome may be a therapeutic target in aortic dysfunction and vascular inflammatory lesions.

Inhibition of angiotensin II receptor I prevents inflammation and bone loss in periodontitis

BACKGROUND

Periodontal disease is characterized by alveolar bone destruction and degenerative lesions of the periodontal ligament (PDL); it is initiated by bacterial infection of the oral cavity, but the clinical effects are secondary to an aberrant host immune response. Primary hypertension (PH), which causes significant morbidity and mortality worldwide, has also been shown to be an inflammatory disease characterized by aberrant immune cell infiltration and activation. Clinical retrospective studies have shown a link between PH and periodontitis with PH exacerbating periodontitis and vice versa, but the pathophysiologic mechanisms responsible for this remain unknown.

METHODS

In this study, we investigate the underlying mechanisms behind PH exacerbation of periodontitis by using a bacteria-induced periodontitis model in normotensive and hypertensive (Nos3^-/- ) mice treated with or without an Angiotensin II (Ang II) specific receptor 1 (AT1) antagonist, losartan. The histologic analyses including immunohistochemistry, immunofluorescence were carried out. The qRT-PCR and ELISAs were applied for the target gene and protein detection.

RESULTS

We find that PH worsens bone resorption and PDL destruction in periodontitis and that treatment with losartan, rescues this. We also show that PH increases dendritic cell (DC) and osteoclast (OC) infiltration in periodontitis, which is also dependent on Ang II. Finally, we show that PH augments the pro-inflammatory state in periodontitis infiltrating DCs in an Ang II-dependent manner and use in vitro studies to show that Ang II directly augments DC Toll-like receptor 4 (TLR4) signaling.

CONCLUSION

Our studies show a central role for Ang II as a pro-inflammatory Toll-like receptor mediator in the pathogenesis of PH-exacerbated periodontitis, indicating that Ang II may be a reasonable target in patients with PH and periodontitis comorbidity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Mechanisms in hypertension and target organ damage: Is the role of the thymus key? (Review)

A variety of cells and cytokines have been shown to be involved in the whole process of hypertension. Data from experimental and clinical studies on hypertension have confirmed the key roles of immune cells and inflammation in the process. Dysfunction of the thymus, which modulates the development and maturation of lymphocytes, has been shown to be associated with the severity of hypertension. Furthermore, gradual atrophy, functional decline or loss of the thymus has been revealed to be associated with aging. The restoration or enhancement of thymus function via upregulation in the expression of thymus transcription factors forkhead box N1 or thymus transplantation may provide an option to halt or reverse the pathological process of hypertension. Therefore, the thymus may be key in hypertension and associated target organ damage, and may provide a novel treatment strategy for the clinical management of patients with hypertension in addition to different commercial drugs. The purpose of this review is to summarize and discuss the advances in our understanding of the impact of thymus function on hypertension from data from animal and human studies, and the potential mechanisms.

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.

The Vascular-Renal Connection in Patients Hospitalized With Hypertensive Crisis: A Population-Based Study

OBJECTIVE

To determine the risks of acute kidney injury development and long-term clinical outcomes of patients with hypertensive crisis.

PATIENTS AND METHODS

This was a population study of Olmsted County residents with hypertensive crisis between January 1, 2000, and December 31, 2008, with follow-up until June 30, 2016.

RESULTS

The results demonstrated that those with underlying chronic kidney disease upon admission for hypertensive crisis, defined as a systolic blood pressure above 180 mm Hg or diastolic blood pressure above 120 mm Hg, were more likely to develop acute kidney injury during hospitalization (odds ratio, 6.04; 95% CI, 1-26; P=.02). Hospitalization length of stay was increased when patients developed acute kidney injury during hypertensive crisis hospitalization (7.6±9 vs 3.4±4 days; P=.04). Furthermore, those who developed acute kidney injury had increased cardiac rehospitalization frequency over 10 years (87% vs 46%; P=.009). These results suggest that those with poor renal reserve are more likely to have further acute kidney damage in the setting of hypertensive crisis, likely due to decreased renal perfusion and neurohormonal dysregulation.

CONCLUSION

In patients hospitalized for hypertensive crisis, chronic renal insufficiency was a risk factor associated with acute kidney injury development during hospitalization. Those who developed acute kidney injury had longer hospitalizations with increased rehospitalization frequency. Future studies are warranted to further investigate whether the preservation of renal function will improve clinical outcomes in hospitalized patients with hypertensive crisis.

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

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