From bedside to bench to bedside: role of renin-angiotensin-aldosterone system in remodeling of resistance arteries in hypertension

Age and vascular aging: an unexplored frontier

Vascular age is an emerging field in cardiovascular risk assessment. This concept includes multifactorial changes in the arterial wall, with arterial stiffness as its most relevant manifestation, leading to increased arterial pressure and pulsatile flow in the organs. Today, the approved test for measuring vascular age is pulse wave velocity, which has been proven to predict cardiovascular events. Furthermore, vascular phenotypes, such as early vascular aging and "SUPERNOVA," representing phenotypic extremes of vascular aging, have been found. The identification of these phenotypes opens a new field of study in cardiovascular physiology. Lifestyle interventions and pharmacological therapy have positively affected vascular health, reducing arterial stiffness. This review aims to define the concepts related to vascular age, pathophysiology, measurement methods, clinical signs and symptoms, and treatment.

Microcirculation in Hypertension: A Therapeutic Target to Prevent Cardiovascular Disease?

Arterial hypertension is a common condition worldwide and an important risk factor for cardio- and cerebrovascular events, renal diseases, as well as microvascular eye diseases. Established hypertension leads to the chronic vasoconstriction of small arteries as well as to a decreased lumen diameter and the thickening of the arterial media or wall with a consequent increased media-to-lumen ratio (MLR) or wall-to-lumen ratio (WLR). This process, defined as vascular remodeling, was firstly demonstrated in small resistance arteries isolated from subcutaneous biopsies and measured by micromyography, and this is still considered the gold-standard method for the assessment of structural alterations in small resistance arteries; however, microvascular remodeling seems to represent a generalized phenomenon. An increased MLR may impair the organ flow reserve, playing a crucial role in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage and related cardiovascular events, thus possessing a relevant prognostic relevance. New non-invasive techniques, such as scanning laser Doppler flowmetry or adaptive optics, are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles; recently, also retinal microvascular WLR was demonstrated to have a prognostic impact in terms of cardio- and cerebrovascular events. A rarefaction of the capillary network has also been reported in hypertension, which may contribute to flow reduction in and impairment of oxygen delivery to different tissues. These microvascular alterations seem to represent an early step in hypertension-mediated organ damage since they might contribute to microvascular angina, stroke, and renal dysfunction. In addition, they can be markers useful in monitoring the beneficial effects of antihypertensive treatment. Additionally, conductance arteries may be affected by a remodeling process in hypertension, and an interrelationship is present in the structural changes in small and large conductance arteries. The review addresses the possible relations between structural microvascular alterations and hypertension-mediated organ damage, and their potential improvement with antihypertensive treatment.

Microcirculation and Physical Exercise In Hypertension

Hypertension is associated with important alterations in the morphology of small arteries and arterioles. Vascular-specific manifestations are changes in the structure and function of vascular smooth muscle cells, extracellular matrix, perivascular tissues, and endothelial cells. Arteriole and capillary remodeling and capillary rarefaction have been observed in hypertensive animals and human beings which contribute to increased vascular resistance. An impairment of different angiogenetic factors, such as VEGF (vascular endothelial growth factor), VEGFR-2 (vascular endothelial growth factor receptor-2), TIMP-1 (tissue inhibitor matrix metalloproteinases-1), and TSP-1 (thrombospondin-1), seems to be responsible for the reduction of the microvascular network. Exercise training has been shown to improve vascular structure and function in hypertension not only in the large arteries but also in the peripheral circulation. Exercise training may regress microvascular remodeling and normalize capillary density, leading to capillary growth possibly by increasing proangiogenic stimuli such as VEGF. Exercise enhances endothelium-dependent vascular relaxation through nitric oxide release increase and oxidative stress reduction. Other mechanisms include improved balance between prostacyclin and thromboxane levels, lower circulating levels of endothelin-1, attenuation of infiltration of immune cells into perivascular adipose tissue, and increase of local adiponectin secretion. In addition, exercise training favorably modulates the expression of several microRNAs leading to a positive modification in muscle fiber composition. Identifying the bioactive molecules and biological mechanisms that mediate exercise benefits through pathways that differ from those used by antihypertensive drugs may help to improve our knowledge of hypertension pathophysiology and facilitate the development of new therapeutic strategies.

Mouse endothelial OTUD1 promotes angiotensin II-induced vascular remodeling by deubiquitinating SMAD3

Understanding the molecular mechanisms of pathological vascular remodeling is important for treating cardiovascular diseases and complications. Recent studies have highlighted a role of deubiquitinases in vascular pathophysiology. Here, we investigate the role of a deubiquitinase, OTUD1, in angiotensin II (Ang II)-induced vascular remodeling. We detect upregulated OTUD1 in the vascular endothelium of Ang II-challenged mice and show that OTUD1 deletion attenuates vascular remodeling, collagen deposition, and EndMT. Conversely, OTUD1 overexpression aggravates these pathological changes both in vivo and in vitro. Mechanistically, SMAD3 is identified as a substrate of OTUD1 using co-immunoprecipitation followed by LC-MS/MS. We find that OTUD1 stabilizes SMAD3 and facilitates SMAD3/SMAD4 complex formation and subsequent nuclear translocation through both K48- and K63-linked deubiquitination. OTUD1-mediated SMAD3 activation regulates transcription of genes involved in vascular EndMT and remodeling in HUVECs. Finally, SMAD3 inhibition reverses OTUD1-promoted vascular remodeling. Our findings demonstrate that endothelial OTUD1 promotes Ang II-induced vascular remodeling by deubiquitinating SMAD3. We identify SMAD3 as a target of OTUD1 and propose OTUD1 as a potential therapeutic target for diseases related to vascular remodeling.

Maternal exercise upregulates the DNA methylation of Agtr1a to enhance vascular function in offspring of hypertensive rats

The angiotensin II signaling system regulates vascular dysfunction and is involved in the programming of hypertension. Maternal exercise has been linked to both short-term and long-term benefits for the mother and fetus. However, the impacts of maternal exercise on the intravascular renin-angiotensin system (RAS) in hypertensive offspring remain unexamined. This study examined whether maternal exercise has an epigenetic effect in repressing angiotensin II type 1 receptor (AT₁R) expression, which leads to favorable alterations in the mesenteric artery (MA) function of spontaneously hypertensive offspring. Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) pregnant rats were randomly divided into an exercise group and a control group. Blood pressure, vascular tone, AT₁R protein and mRNA expression, and AT₁R gene (Agtr1a) promoter methylation status were examined in the MAs of 3-month-old male offspring. Maternal exercise significantly reduced the resting blood pressure and cardiovascular reactivity of offspring from SHRs. Furthermore, Ang II-AT₁R activity in regulating vascular tone and AT₁R expression was decreased in the MAs of the SHR offspring from the exercise groups. Importantly, exercise during gestation suppressed AT₁R expression via hypermethylation of the Agtr1a promoter region and upregulated DNA methyltransferase (DNMT) expression in MAs of SHR offspring. These results suggest that maternal exercise upregulates DNMT expression, resulting in hypermethylation and repression of the Agtr1a gene, which may prevent MA dysfunction in the offspring of SHRs. A mechanistic model on the epigenetics of exercise during pregnancy. Maternal exercise during pregnancy triggers hypermethylation and transcriptional suppression of the Agtr1a gene via increased DNMT1 and DNMT3B expression in MAs of SHR offspring. Downregulation of AT1R expression reduces the contribution of Ang II to vascular tone, ultimately improving vascular structure and function. VSMC vascular smooth muscle cell; Ang II angiotensin II; AT1aR angiotensin type 1 receptor (AT1R) alpha subtypes; Agtr1a AT1R alpha isoform gene; MAs mesenteric arteries; BP blood pressure.

Cyclooxygenase-2 is a critical determinant of angiotensin II-induced vascular remodeling and stiffness in resistance arteries of ouabain-treated rats

OBJECTIVE

To investigate the role of angiotensin II/AT 1 receptor signaling and/or cyclooxygenase-2 (COX-2) activation on vascular remodeling and stiffening of the mesenteric resistance arteries (MRA) of ouabain-treated rats.

METHODS

Ouabain-treated (OUA, 30 μg kg/day for 5 weeks) and vehicle (VEH)-treated Wistar rats were co-treated with losartan (LOS, AT 1 R antagonist), nimesulide (NIM, COX-2 inhibitor) or hydralazine hydrochloride plus hydrochlorothiazide. MRA structure and mechanics were assessed with pressure myography and histology. Picrosirius red staining was used to determine the total collagen content. Western blotting was used to detect the expression of collagen I/III, MMP-2, Src, NFκB, Bax, Bcl-2 and COX-2. Reactive oxygen species (ROS) and plasma angiotensin II levels were measured by fluorescence and ELISA, respectively.

RESULTS

Blockade of AT 1 R or inhibition of COX-2 prevented ouabain-induced blood pressure elevation. Plasma angiotensin II level was higher in OUA than in VEH. LOS, but not hydralazine hydrochloride with hydrochlorothiazide, prevented inward hypotrophic remodeling, increased collagen deposition and stiffness, and oxidative stress in OUA MRA. LOS prevented the reduction in the total number of nuclei in the media layer and the Bcl-2 expression induced by OUA in MRA. The higher pSrc/Src ratio, NFκB/IκB ratio, and COX-2 expression in OUA MRA were also prevented by LOS. Likewise, COX-2 inhibition prevented vascular remodeling, mechanical changes, oxidative stress and inflammation in OUA MRA.

CONCLUSION

The results suggest that, regardless of hemodynamic adjustments, the angiotensin II/AT 1 R/pSrc/ROS/NFκB/COX-2 pathway is involved in the development of MRA inward hypotrophic remodeling and stiffness in ouabain-treated rats.

The Molecular Mechanism of Aerobic Exercise Improving Vascular Remodeling in Hypertension

The treatment and prevention of hypertension has been a worldwide medical challenge. The key pathological hallmark of hypertension is altered arterial vascular structure and function, i.e., increased peripheral vascular resistance due to vascular remodeling. The aim of this review is to elucidate the molecular mechanisms of vascular remodeling in hypertension and the protective mechanisms of aerobic exercise against vascular remodeling during the pathological process of hypertension. The main focus is on the mechanisms of oxidative stress and inflammation in the pathological condition of hypertension and vascular phenotypic transformation induced by the trilaminar structure of vascular endothelial cells, smooth muscle cells and extracellular matrix, and the peripheral adipose layer of the vasculature. To further explore the possible mechanisms by which aerobic exercise ameliorates vascular remodeling in the pathological process of hypertension through anti-proliferative, anti-inflammatory, antioxidant and thus inhibiting vascular phenotypic transformation. It provides a new perspective to reveal the intervention targets of vascular remodeling for the prevention and treatment of hypertension and its complications.

Large‐Conductance Calcium‐Activated Potassium Channel Opener, NS1619, Protects Against Mesenteric Artery Remodeling Induced by Agonistic Autoantibodies Against the Angiotensin II Type 1 Receptor

Background

Agonistic autoantibodies against the angiotensin II type 1 receptor (AT1‐AAs) extensively exist in patients with hypertensive diseases and have been demonstrated to play crucial roles in the pathophysiological process of vascular remodeling. However, the treatment options are limited. The large‐conductance calcium‐activated potassium (BK) channel is a critical regulator and potential therapeutic target of vascular tone and architecture. We have previously observed that AT1‐AAs have an inhibitory effect on BK channels. However, whether BK channel dysfunction is involved in AT1‐AAs‐induced vascular remodeling and the therapeutic effect of BK channel opener is unclear.

Methods and Results

In our study, mesenteric arteries from AT1‐AAs‐positive rats exhibited increased wall thickness, narrowing of the arteriolar lumen, and increased collagen accumulation. Patch clamp test results showed that the voltage sensitivity of BK channel declined in mesenteric arteriolar smooth muscle cells from AT1‐AAs‐positive rats. Experiments with freshly isolated mesenteric arteriolar smooth muscle cells showed that AT1‐AAs reduced the opening probability, open levels, open dwell time, and calcium sensitivity of BK channel. Experiments with HEK293T cells transfected with GFP‐ZERO‐BK α‐subunit plasmids suggested a BK channel α‐subunit‐dependent mechanism. BK channel α‐subunit deficient, namely KCNMA1^−/− rats showed a phenotype of mesenteric artery remodeling. The administration of NS1619, a specific BK channel opener targeting the α‐subunit, reversed the phenotypic transition and migration induced by AT1‐AAs in cultured mesenteric arteriolar smooth muscle cells. Finally, perfusion of NS1619 significantly relieved the pathological effects induced by AT1‐AAs in vivo.

Conclusions

In summary, we provide compelling evidence that BK channel α‐subunit dysfunction mediates AT1‐AAs‐induced mesenteric artery remodeling. Preservation of BK channel activity may serve as a potential strategy for the treatment of AT1‐AAs‐induced maladaptive resistance artery remodeling.

Antioxidant Stress and Anti-Inflammatory Activities of Egg White Proteins and Their Derived Peptides: A Review

Oxidative stress and chronic inflammation are the common pathological bases of chronic diseases such as atherosclerosis, cancer, and cardiovascular diseases, but most of the treatment drugs for chronic diseases have side effects. There is an increasing interest to identify food-derived bioactive compounds that can mitigate the pathological pathways associated with oxidative stress and chronic inflammation. Egg white contain a variety of biologically active proteins, many of which have antioxidant and anti-inflammatory activities and usually show better activity after enzymatic hydrolysis. This review covers the antioxidative stress and anti-inflammatory activities of egg white proteins and their derived peptides and clarifies their mechanism of action in vivo and in vitro. In addition, the link between oxidative stress and inflammation as well as their markers are reviewed. It suggests the potential application of egg white proteins and their derived peptides and puts forward further research prospects.

Purification of Angiotensin-Converting Enzyme (ACE) from Sheep Kidney and Inhibition Effect of Reduced Nicotinamide Adenine Dinucleotide (NADH) on Purified ACE Activity

Angiotensin-converting enzyme (ACE, EC 3.4.15.1) is a significant enzyme that regulates blood pressure. ACE inhibitors are often used in the treatment of hypertension. In this work, ACE was purified and characterized in one step with affinity chromatography from sheep kidneys. ACE was 10305-fold purified and specific activity was 19,075 EU/mg protein. The molecular weight and purity of ACE were found with SDS-PAGE and observed two bands at about 60 kDa and 70 kDa on the gel. The effects of reduced nicotinamide adenine dinucleotide (NADH), an antioxidant compound, on purified ACE activity were also researched. NADH on ACE activity showed an inhibition effect. The inhibition type of NADH was determined to be non-competitive inhibition by the Lineweaver-Burk chart and IC₅₀ and K_i values for NADH were 244.33 and 175.08 µM, respectively. These results suggest that antioxidant substances might be efficient in preventing hypertension.

Association between renin-angiotensin-aldosterone system inhibitors and risk of dementia: A meta-analysis

OBJECTIVE

To evaluate the association of all RAAS inhibitors, ACE inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on dementia onset (any dementia, Alzheimer's disease and vascular dementia) using a meta-analytic approach.

METHODS

A systematic MEDLINE search was carried out to identify all observational studies published up to the 30th September 2020 evaluating the association between RAAS inhibitors and risk of dementia. Studies were included if original investigations considering incident dementia cases, with ACEIs and/or ARBs as exposure and other antihypertensives (AHs) use as reference, and if reporting association estimates and relative variability measures. Random effect pooled relative risks (pRR) and the corresponding 95% confidence intervals (95%CI) were calculated according to DerSimonian and Laird's (DL) or to Hartung Knapp Sidik Jonkman (HKSJ) method depending on the number of studies and between-studies heterogeneity. A linear mixed meta-regression model (MM) was applied to take into account correlation among association estimates from the same study.

RESULTS

15 studies were included in the meta-analysis. ARBs but not ACEIs' use led to a significant reduction of the risk of any dementia (pRR 0.78, 95%CI_MM 0.70-0.87) and Alzheimer's disease (pRR 0.73, 95%CI_MM 0.60-0.90). Moreover, when compared to ACEIs, ARBs reduced of 14% the risk of any dementia (pRR 0.86, 95%CI_DL 0.79-0.94).

CONCLUSIONS

ARBs but not ACEIs led to a reduction in the risk of any dementia. The difference between ARBs and ACEIs in terms of preventive effectiveness could be due to distinct profiles of antagonism towards independent receptor pathways or to differential influences on amyloid metabolism.

Ischemic Conditioning Ameliorated Hypertension and Vascular Remodeling of Spontaneously Hypertensive Rat via Inflammatory Regulation

Vascular remodeling is an initial step in the development of hypertension. Limb remote ischemic conditioning (LRIC) is a physiological treatment that induces endogenous protective effect during acute ischemic injury. However, the impact of long-term LRIC on hypertension, a chronic disease, is unknown. In this study, we aimed to investigate the LRIC effect on blood pressure and vascular remodeling in spontaneously hypertensive rat (SHR) model and patients with prehypertension and early-stage hypertension. LRIC of rats was performed once a day for 6-weeks. Blood pressure, vascular remodeling (cross-sectional area, extracellular deposition, and smooth muscle cell area), inflammation (inflammatory factors, and inflammatory cells) were compared among normotensive Wistar-Kyoto rats (WKY), WKY RIC group, SHR control group, and SHR RIC. Long-term LRCI treatment (twice a day for 4-weeks) was performed on patients with prehypertension or early-stage hypertension. Blood pressure and pulse wave velocity (PWV) were analyzed before and after LRIC treatment. LRIC treatment decreased blood pressure in SHR (n = 9-10). LRIC ameliorated vascular remodeling by decreasing cross-sectional area, suppressing deposition of the extracellular matrix, and hypertrophy of smooth muscle cell in conduit artery and small resistance artery (n = 7). LRIC decreased proinflammatory factors while increasing the anti-inflammatory factors in the circulation (n = 5). LRIC decreased circulating monocyte and natural killer T-cell levels (n = 5). Furthermore, LRIC treatment decreased blood pressure and improved vascular stiffness in patients (n = 20). In conclusion, long term LRIC could decrease blood pressure and ameliorate vascular remodeling via inflammation regulation. LRIC could be a preventive treatment for people with blood pressure elevation or prehypertension.

The Inflammation Network in the Pathogenesis of Erectile Dysfunction: Attractive Potential Therapeutic Targets

BACKGROUND

Erectile dysfunction (ED) is an evolving health problem in the aging male population. Chronic low-grade inflammation is a critical component of ED pathogenesis and a probable intermediate stage of endothelial dysfunction, especially in metabolic diseases, with the inclusion of obesity, metabolic syndrome, and diabetes.

OBJECTIVE

This review will present an overview of preclinical and clinical data regarding common inflammatory mechanisms involved in the pathogenesis of ED associated with metabolic diseases and the effect of antiinflammatory drugs on ED.

METHODS

A literature search of existing pre-clinical and clinical studies was performed on databases [Pubmed (MEDLINE), Scopus, and Embase] from January 2000 to October 2019.

RESULTS

Low-grade inflammation is a possible pathological role in endothelial dysfunction as a consequence of ED and other related metabolic diseases. Increased inflammation and endothelial/prothrombotic markers can be associated with the presence and degree of ED. Pharmacological therapy and modification of lifestyle and risk factors may have a significant role in the recovery of erectile response through reduction of inflammatory marker levels.

CONCLUSION

Inflammation is the least common denominator in the pathology of ED and metabolic disorders. The inflammatory process of ED includes a shift in the complex interactions of cytokines, chemokines, and adhesion molecules. These data have established that anti-inflammatory agents could be used as a therapeutic opportunity in the prevention and treatment of ED. Further research on inflammation-related mechanisms underlying ED and the effect of therapeutic strategies aimed at reducing inflammation is required for a better understanding of the pathogenesis and successful management of ED.

TLR2 regulates angiotensin II-induced vascular remodeling and EndMT through NF-κB signaling

Excessive vascular remodeling has been shown in hypertensive patients. In experimental models of hypertensive vascular injury, such as angiotensin II (Ang II) challenged mice, toll like receptor 2 (TLR2) initiates inflammatory responses. More recently, studies have reported atypical endothelial to mesenchymal transition (EndMT) in vascular injuries and inflammatory conditions. Here, we aimed to investigate whether TLR2 mediates Ang II-induced vascular inflammation and initiates EndMT. In a mouse model of angiotensin II-induced hypertension, we show that aortas exhibit increased medial thickening, fibrosis, and features of EndMT. These alterations were not observed in TLR2 knockout mice in response to Ang II. TLR2 silencing in cultured endothelial cells confirmed the essential role of TLR2 in Ang II-induced inflammatory factor induction, and EndMT-associated phenotypic change. Mechanistically, we found Ang II activates nuclear factor-κB signaling, inducing pro-inflammatory cytokine production, and mediates EndMT in both cultured endothelial cells and in mice. These studies illustrate a novel role of TLR2 in regulating Ang II-induced deleterious vascular remodeling through the induction of EndMT. The studies also suggest that TLR2 may be targeted to alleviate hypertension-associated vascular injury.

Beneficial Effects of Spirulina Aqueous Extract on Vasodilator Function of Arteries from Hypertensive Rats

Hypertension is a multifactorial disorder considered one of the major causes of premature death worldwide. This pathology is associated with vascular functional/structural alterations in which nitric oxide (NO) and oxygen reactive species participate. On the other hand, the use of microalgae extracts in the treatment of cardiovascular diseases is increasing. Based on the antioxidant and antihypertensive properties of Spirulina, this study aims to investigate the effect of an aqueous extract of Spirulina on the vasodilator function of the aorta from spontaneously hypertensive rats (SHR), analyzing the functional role of NO. For this, aortic segments from male SHR were divided into two groups, one control and the other exposed to an Spirulina aqueous extract (0.1% w/v, for 3 hours), to analyze (i) the production of NO, superoxide anion, and hydrogen peroxide; (ii) the vasodilator response induced by acetylcholine (ACh), by the NO donor and sodium nitroprusside (SNP), and by the KATP channel opener and pinacidil; and (iii) the expression of the p-Akt, p-eNOS, and HO-1 proteins. The results showed that the aqueous Spirulina extract (i) increased the production of NO, did not significantly modify that of superoxide, while decreased that of hydrogen peroxide; (ii) increased the vasodilatory responses induced by ACh, NPS, and pinacidil; and (iii) increased the expression of p-Akt and HO-1. These results suggest that incubation with the aqueous Spirulina extract improves the vascular function of arteries from SHR by increasing the release/bioavailability/function of NO. Increased KATP channel activation and expression of pAkt and HO-1 appear to be participating in these actions.

Reference values of retinal microcirculation parameters derived from a population random sample

Retinal microcirculation reflects retinal perfusion abnormalities and retinal arterial structural changes at relatively early stages of various cardiovascular diseases. Our objective has been to establish reference values for major functional and structural parameters of retinal microcirculation in a randomly selected urban population sample. A total of 398 randomly selected individuals from an urban population aged 25 to 65 years, resident in Pilsen, Czech Republic, were screened for major cardiovascular risk factors. Retinal microcirculation was assessed using scanning laser Doppler flowmetry (SLDF), with data evaluable in 343 patients. Of this number, complete data were available for 256 individuals free from manifest cardiovascular disease, diabetes and drug treatment for hypertension and/or dyslipidemia, constituting the reference value population. Juxtapapillary retinal capillary blood flow has increased significantly with age whereas vessel and luminal diameters have decreased. No sex differences in retinal microcirculation parameters have been found. Therefore, reference values for retinal microcirculation parameters have been established by age groups. Unattended automated office systolic BP, after adjusting for age, correlated significantly with wall-to-lumen ratio (WLR) and wall thickness (WT). Moreover, after adjusting for age and mean BP, a positive relationship has been found between carotid femoral pulse wave velocity and WT, WLR and wall cross-sectional area, indicating the interaction between micro- and macro-vasculature. In conclusion, our study is the first to provide reference values of retinal microcirculation parameters in a random Caucasian population sample. Our results have shown that, at the population level, the first structural changes in retinal microcirculation are those in lumen diameters. Of note, a close relationship between BP and vascular remodeling of retinal arterioles and between aortic stiffness and WLR of retinal arterioles suggests an interaction between micro- and macro-vasculature.

Angiotensin II-Induced Cardiovascular Fibrosis Is Attenuated by NO-Sensitive Guanylyl Cyclase1

In the NO/cGMP signaling cascade, relevant in the cardiovascular system, two NO-sensitive guanylyl cyclase (NO-GC) isoforms are responsible for NO-dependent cGMP generation. Here, the impact of the major NO-GC isoform, NO-GC1, on fibrosis development in the cardiovascular system was studied in NO-GC1-deficient mice treated with AngiotensinII (AngII), known to induce vascular and cardiac remodeling. Morphometric analysis of NO-GC1 KO’s aortae demonstrated an enhanced increase of perivascular area after AngII treatment accompanied by a higher aortic collagen1 mRNA content. Increased perivascular fibrosis also occurred in cardiac vessels of AngII-treated NO-GC1 KO mice. In line, AngII-induced interstitial fibrosis was 32% more pronounced in NO-GC1 KO than in WT myocardia associated with a higher cardiac Col1 and other fibrotic marker protein content. In sum, increased perivascular and cardiac interstitial fibrosis together with the enhanced collagen1 mRNA content in AngII-treated NO-GC1-deficient mice represent an exciting manifestation of antifibrotic properties of cGMP formed by NO-GC1, a finding with great pharmaco-therapeutic implications.

Mitochondrial Contact Sites in Inflammation-Induced Cardiovascular Disease

The mitochondrion, the ATP-producing center, is both physically and functionally associated with almost all other organelles in the cell. Mitochondrial-associated membranes (MAMs) are involved in a variety of biological processes, such as lipid exchange, protein transport, mitochondrial fission, mitophagy, and inflammation. Several inflammation-related diseases in the cardiovascular system involve several intracellular events including mitochondrial dysfunction as well as disruption of MAMs. Therefore, an in-depth exploration of the function of MAMs will be of great significance for us to understand the initiation, progression, and clinical complications of cardiovascular disease (CVD). In this review, we summarize the recent advances in our knowledge of MAM regulation and function in CVD-related cells. We discuss the potential roles of MAMs in activating inflammation to influence the development of CVD.

Eplerenone improves endothelial function and arterial stiffness and inhibits Rho-associated kinase activity in patients with idiopathic hyperaldosteronism: a pilot study

OBJECTIVE

Primary aldosteronism is one of the most common cause of secondary hypertension. It is well known that the incidence of cardiovascular events is higher in patients with primary aldosteronism than in patients with essential hypertension. In a previous study, we showed that aldosterone-producing adenoma is associated with vascular function and structure. The aim of this study was to evaluate the effects of eplerenone on vascular function in the macrovasculature and microvasculature, arterial stiffness and Rho-associated kinase (ROCK) activity in patients with idiopathic hyperaldosteronism (IHA).

METHODS

Vascular function, including reactive hyperemia index (RHI), flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID), arterial stiffness including brachial-ankle pulse wave velocity (baPWV) and brachial intima-media thickness (IMT) and ROCK activity in peripheral leukocytes were measured before and after 12 weeks of treatment with eplerenone in 50 patients with IHA.

RESULTS

After 12 weeks, eplerenone decreased the aldosterone renin ratio but did not alter SBP and DBP. Eplerenone treatment increased log RHI from 0.56 ± 0.25 to 0.69 ± 0.25 (P < 0.01) and NID from 12.8 ± 5.8 to 14.9 ± 6.9% (P = 0.02) and it decreased baPWV from 1540 ± 263 to 1505 ± 281 (P = 0.04) and ROCK activity from 1.20 ± 0.54 to 0.89 ± 0.42 (P < 0.01), whereas there was no significant change in FMD (increase from 4.6 ± 3.4 to 4.6 ± 3.6%, P = 0.99) or brachial IMT (decrease from 0.28 ± 0.07 to 0.28 ± 0.04 mm, P = 0.14).

CONCLUSION

Eplerenone improves microvascular endothelial function, vascular smooth muscle function, arterial stiffness and ROCK activity in patients with IHA.

CLINICAL TRIAL REGISTRATION INFORMATION

URL for Clinical Trial: http://UMIN; Registration Number for Clinical Trial: UMIN000003409.

Calcilytic NPS2143 promotes proliferation and inhibits apoptosis of spontaneously hypertensive rat vascular smooth muscle cells via activation of the renin-angiotensin system

Vascular smooth muscle cell (VSMC) proliferation and apoptosis and the renin-angiotensin system (RAS) play critical roles in the development of essential hypertension. The activation of calcium-sensing receptor (CaSR), functionally expressed in VSMCs, inhibits cyclic adenosine monophosphate (cAMP) formation by elevating intracellular calcium ([Ca²⁺]_i) and then suppressing renin release. The present study aimed to investigate the effects of NPS2143-mediated inhibition of CaSR on VSMC proliferation and apoptosis in spontaneously hypertensive rat (SHR) VSMCs and to assess whether these effects were mediated by alterations to RAS signaling. Primary VSMCs were isolated from the aortas of SHRs and Wistar-Kyoto rats. SHR VSMCs were treated with CaSR antagonist NPS2143 and cell proliferation and CaSR and RAS-related protein expression levels were measured to assess the effect. The results indicated that NPS2143 treatment promoted SHR VSMC proliferation, lower CaSR expression levels and higher RAS-related proteins levels when compared with control treatment. Additional measurement of the expression levels of proteins related to proliferation, remodeling, apoptosis and RAS related proteins, as well as cell viability, cell cycle, cell apoptosis ratio, [Ca²⁺]_i, and the concentration of cAMP was performed after treatment with NPS2143, PLC inhibitor U73122, IP3 receptor antagonist 2-aminoethoxydiphenylborane (APB), adenylyl cyclase-V inhibitor MDL12330A, angiotensin converting enzyme inhibitor captopril, angiotensin I receptor (AT1R) inhibitor losartan, NPS2143 + U73122, NPS2143 + 2-APB, NPS2143 + MDL12330A, NPS2143 + captopril and NPS2143 + losartan. The results suggested that NPS2143 promoted cell proliferation, inhibited cell apoptosis, decreased [Ca²⁺]_i and increased the expression of RAS compared with control treatments. NPS2143 + U73122 and NPS2143 + 2-APB enhanced the effects of NPS2143, while NPS2143 + MDL12330A, NPS2143 + captopril, NPS2143 + losartan attenuated the effected of NPS2143 in SHR VSMCs. Furthermore, the knockdown of AT1R by AT1R-short hairpin RNA also attenuated the effects of NPS2143 compared with NPS2143 alone. Collectively, these data indicated that NPS2143 promoted proliferation and inhibited apoptosis of VSMCs in SHRs, the effect of which was achieved by activation of RAS signaling.

Water-Soluble Polysaccharides from Ephedra alata Stems: Structural Characterization, Functional Properties, and Antioxidant Activity

In this study, the physicochemical characterization, functional properties, and antioxidant activity of polysaccharides extracted from Ephedra alata (EAP) were investigated. EAP were extracted in water during 3 h with a liquid/solid ratio of 5 in a water bath at 90 °C. The structure of the extracted EAP was examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and gas chromatography-mass spectrometry (GC-MS). The functional properties and biochemical activities of EAP were determined. The chemical analysis revealed that the contents of carbohydrates, uronic acid, and proteins were 73.24% ± 1.24%, 6.82% ± 0.57%, and 6.56% ± 0.36%, respectively. The results showed that the extracted EAP essentially contain three functional groups: C=O, C-H, and O-H. SEM images showed that EAP present numerous high porosity particles. The monosaccharide composition revealed a polymer composed of glucose (43.1%), galactose (36.4%), mannose (14.9%), arabinose (3.7%), and gluconic acid (1.7%). EAP showed interesting functional properties (solubility, oil holding capacity, foaming and emulsion properties). Finally, the results revealed that EAP displayed excellent antihypertensive and antioxidant activities. Overall, EAP present a promising natural source of food additives, antioxidants, and antihypertensive agents.

Blockade of intercellular adhesion molecule-1 prevents angiotensin II-induced hypertension and vascular dysfunction

Monocyte and adhesion infiltration into the arterial subendothelium are initial steps in hypertension development. The endothelial intercellular adhesion molecule-1 (ICAM-1) has been implicated in the recruitment and adhesion of leukocytes in several cardiac diseases. However, the role of ICAM-1 in angiotensin II (Ang II)-induced hypertension development remains unknown. Hypertension was induced by administering an infusion of Ang II (1000 ng/kg/min) to wild-type (WT) mice treated with an IgG control or ICAM-1 neutralizing antibody (1 and 2 mg/mouse/day, respectively). Blood pressure was determined using the tail-cuff system. Vascular remodeling was assessed by performing a histological examination. Inflammation and reactive oxygen species (ROS) levels were determined by using immunostaining. Vascular dysfunction was assessed by aortic ring assay. The expression of fibrotic markers, cytokines and NOX was evaluated by quantitative real-time PCR analysis. Our results demonstrate that Ang II infusion markedly increased the ICAM-1 level in the aorta. Blocking ICAM-1 with a neutralizing antibody significantly attenuated Ang II-induced arterial hypertension, vascular hypertrophy, fibrosis, macrophage infiltration, and ROS production and improved vascular relaxation. In conclusion, ICAM-1-mediated monocyte adhesion and migration play a critical role in Ang II-induced arterial hypertension and vascular dysfunction. ICAM-1 inhibitors may represent a new therapeutic strategy for the treatment of this disease.

Effects of Angiotensin-(1-7) and Angiotensin II on Acetylcholine-Induced Vascular Relaxation in Spontaneously Hypertensive Rats

Endothelial dysfunction of small arteries occurs in patients with hypertension and in various hypertensive models. Endothelial function is usually evaluated by the degree of acetylcholine- (ACh-) induced vascular relaxation. Our previous study has found that compared to Wistar-Kyoto rats (WKY), ACh-induced vasodilatation was attenuated significantly in the mesenteric artery (MA), coronary artery (CA), and pulmonary artery (PA) of spontaneously hypertensive rats (SHR). This study investigated the influence of angiotensin- (Ang-) (1-7) and Ang II on blood pressure and ACh-induced vascular relaxation, as well as their interactive roles and downstream signal pathways in SHR and WKY. Intravenous injection of Ang II significantly increased, while Ang-(1-7) decreased the mean arterial pressure (MAP) in SHR. Ang-(1-7) improved ACh-induced relaxation in the MA, CA, and PA of SHR, while Ang II further attenuated it, which were inhibited by pretreatment with Mas receptor antagonist A-779 or AT₁ receptor antagonist losartan, respectively. Ang-(1-7) decreased the basal arterial tension, and Ang II induced great vasoconstriction in SHR. Pretreatment with Ang-(1-7) inhibited the Ang II-induced pressor response, vasoconstriction, and the effects on ACh-induced relaxation in SHR. AT₁ receptor expression was higher, while nitric oxide (NO), cGMP, and protein kinase G (PKG) levels of arteries were lower in SHR than in WKY. Ang II decreased, while Ang-(1-7) increased, the levels of NO, cGMP, and PKG of arteries. In addition, pretreatment with Ang-(1-7) inhibited the Ang II-induced reduction of NO, cGMP, and PKG in SHR. These results indicate that the activation of the Mas receptor by Ang-(1-7) can improve endothelial function and decrease MAP in SHR and inhibit the deteriorative effect of Ang II on endothelial function through the NO-cGMP-PKG pathway.

Sauchinone inhibits angiotensin II-induced proliferation and migration of vascular smooth muscle cells

Hypertension is a common type of cardiovascular disease that remains a major cause of death in the world. Vascular remodelling is an important complication of hypertension, and vascular smooth muscle cells (VSMCs) play a major role in vascular remodelling. Sauchinone is one of the active lignins which has been found to possess vascular protective effects. However, the functional role of sauchinone in hypertension has not been investigated. The aim of this study was to evaluate the role of sauchinone in the angiotensin II (Ang II)-induced vascular remodelling model in VSMCs. The results showed that treatment of sauchinone inhibited Ang II-induced VSMCs proliferation and migration in VSMCs. Sauchinone treatment suppressed the reactive oxygen species (ROS) production and NADPH oxidase (NOX) activity in Ang II-induced VSMCs. The inhibitory effects of Ang II on expressions of VSMCs phenotype markers including α-smooth muscle actin (α-SMA), calponin, osteopontin were mitigated by sauchinone treatment. Furthermore, sauchinone inhibited Ang II-induced over-activation of TGF-β1/Smad3 signalling pathway in VSMCs. Taken together, this study identified sauchinone as a potential agent for preventing vascular remodelling in hypertension.

NEDD4 protects vascular endothelial cells against Angiotensin II-induced cell death via enhancement of XPO1-mediated nuclear export

NEDD4 is an E3 ubiquitin ligase containing the HECT domain, which regulates various cellular processes, but its role in vascular endothelial cells is unknown. In the present study, we found that NEDD4 bound directly to XPO1 by co-immunoprecipitation screening. In HUVECs (human umbilical vein endothelial cells), overexpression of NEDD4 reduced Ang II-induced ROS level and cell apoptosis. Ang II stimulation led to nuclear accumulation of cargoes, while overexpression of NEDD4 enhanced the XPO1-dependent nuclear export of its cargoes. KPT185, an inhibitor of XPO1, can abolished the protective effect of NEDD4 under Ang II treatment. In addition, NEDD4 could promote the interaction between XPO1 and RanBP3 via K63-linked ubiquitination of XPO1. These results suggested that NEDD4 played a protective role in vascular endothelial cell injury through regulating XPO1-mediated nuclear export.

Schizandrin B attenuates angiotensin II induced endothelial to mesenchymal transition in vascular endothelium by suppressing NF-κB activation

BACKGROUND

Angiotensin II (Ang II)-induced chronic inflammation and oxidative stress often leads to irreversible vascular injury, in which the endothelial to mesenchymal transition (EndMT) in the endothelial layers are involved. Schisandrin B (Sch B), a natural product isolated from traditional Schisandra chinensis, has been reported to exert vascular protective properties with unclear mechanism.

HYPOTHESIS/PURPOSE

This study investigated the protective effects and mechanism of Sch B against Ang II-induced vascular injury.

METHODS

C57BL/6 mice were subcutaneous injected of Ang II for 4 weeks to induce irreversible vascular injury. In vitro, Ang II-induced HUVECs injury was used to study the underlying mechanism. The markers of EndMT, inflammation and oxidative stress were studied both in vitro and in vivo.

RESULTS

Pre-administration of Sch B effectively attenuated phenotypes of vascular EndMT and fibrosis in Ang II-treated animals, accompanied with decreased inflammatory cytokine and ROS. The in vitro data from HUVECs suggest that Sch B directly targets NF-κB activation to suppress Ang II-induced EndMT and vascular injury. The activation of EndMT in the presence of Ang II is regulated by the NF-κB, a common player in inflammation and oxidative stress. Ang II-induced inflammation and oxidative stress also contributed to vascular EndMT development and Sch B inhibited inflammation/ROS-mediated EndMT by suppressing NF-κB.

CONCLUSION

EndMT contributes to vascular injury in Ang II-treated mice, and it can be prevented via suppressing NF-κB activation by Sch B treatment. These results also imply that NF-κB might be a promising target to attenuate vascular remodeling induced by inflammation and oxidative stress through an EndMT mechanism.

Persistent elevation of blood pressure by ambient coarse particulate matter after recovery from pulmonary inflammation in mice

Exposure to ambient particulate matter (PM) is associated with hypertension and cardiovascular diseases. Recently, we reported that exposure to fine and coarse PM caused pulmonary inflammation and pulmonary small arterial remodeling in mice, and osteopontin (OPN) level was elevated following PM exposure. However, in the present study, cotreatment with 5-methoxytryptophan for 4 weeks partially reduced coarse PM-induced pulmonary inflammation without reducing pulmonary OPN secretion or recovery from pulmonary arterial remodeling in mice. Persistent vascular dysfunction may lead to vascular remodeling. Therefore, we further compared the relationship between coarse PM-induced inflammation and vascular dysfunction by exposing mice to PM before and after cessation of PM exposure. Oropharyngeal aspiration of PM for 8 weeks induced pulmonary inflammation and pulmonary small artery remodeling in mice, as well as increased serum C-reactive protein and OPN concentrations and systolic blood pressure (SBP). After the cessation of PM exposure for another 8 weeks, lung inflammation had recovered and vascular remodeling had partially recovered. Elevation of OPN, metalloproteinases (MMPs), and cytokines in bronchioalveolar lavage were significantly reduced. However, PM-induced systemic responses did not recover after the cessation of PM exposure. Notably, not only serum OPN and SBP remained significantly elevated; also, serum endothelin-1, MMP-9, and keratinocyte-derived chemokine concentrations were significantly increased after cessation of PM exposure for another 8 weeks. These data suggested that systemic inflammation and systemic vascular dysfunction might be important in PM-induced elevation of SBP. Furthermore, SBP elevation was persistent after cessation of PM exposure for 8 weeks.

Comparison between invasive and noninvasive techniques of evaluation of microvascular structural alterations

BACKGROUND

The evaluation of the morphological characteristics of small resistance arteries in humans is challenging. The gold standard method is generally considered to be the measurement by wire or pressure micromyography of the media-to-lumen ratio of subcutaneous small vessels obtained by local biopsies. However, noninvasive techniques for the evaluation of retinal arterioles were recently proposed; in particular, two approaches, scanning laser Doppler flowmetry (SLDF) and adaptive optics, seem to provide useful information; both of them provide an estimation of the wall-to-lumen ratio (WLR) of retinal arterioles. Moreover, a noninvasive measurement of basal and total capillary density may be obtained by videomicroscopy/capillaroscopy. No direct comparison of these three noninvasive techniques in the same population was previously performed; in particular, adaptive optics was never validated against micromyography.

METHODS

In the current study, we enrolled 41 controls and patients: 12 normotensive lean controls, 12 essential hypertensive lean patients, nine normotensive obese patients and eight hypertensive obese patients undergoing elective surgery. All patients underwent a biopsy of subcutaneous fat during surgery. Subcutaneous small resistance artery structure was assessed by wire micromyography and the media-to-lumen ratio was calculated. WLR of retinal arterioles was obtained by SLDF and adaptive optics. Functional (basal) and structural (total) microvascular density was evaluated by capillaroscopy before and after venous congestion.

RESULTS AND CONCLUSION

Our data suggest that adaptive optics has a substantial advantage over SLDF in terms of evaluation of microvascular morphology, as WLR measured with adaptive optics is more closely correlated with the M/L of subcutaneous small arteries (r = 0.84, P < 0.001 vs. r = 0.52, P < 0.05, slopes of the relations: P < 0.01 adaptive optics vs. SLDF). In addition, the reproducibility of the evaluation of the WLR with adaptive optics is far better, as compared with SLDF, as intraobserver and interobserver variation coefficients are clearly smaller. This may be important in terms of clinical evaluation of microvascular morphology in a clinical setting, as micromyography has substantial limitations in its clinical application due to the local invasiveness of the procedure.

Proinflammatory Role of Angiotensin II in the Aorta of Normotensive Mice

Angiotensin II plays important functions in cardiovascular system mediating actions leading to inflammatory responses such as activation of VSMC in order to produce ROS, inflammatory cytokines, chemokines, and adhesion molecules. Changes in angiotensin II production could stimulate the recruitment and activation of myeloid cells initiating local inflammatory response without effect on BP. We aimed to verify if angiotensin II induces an inflammatory response in the aorta and if it correlates with variations in BP. C57Bl/6 mice treated with saline solution (0.9%, control group) or angiotensin II (30ng/kg, Ang II group) were used. BP and HR levels were measured. Immunohistochemistry for IL1-β, TGF-β, iNOS, CD45, and α-actin was performed in the aorta. BP and HR do not change. A biphasic response was observed both for IL1-β and TGF-β expression and also for the presence of CD45 positive cells, with an acute increase (between 30 and 60 minutes) and a second increase, between 24 and 48 hours. Positive staining for iNOS increased in the earlier period (30 minutes) in perivascular adipose tissue and in a longer period (48 hours) in tunica adventitia. Immunoblotting to α-actin showed no alterations, suggesting that the applied dose of angiotensin II does not alter the aortic VSMCs phenotype. The results suggest that angiotensin II, even at doses that do not alter BP, induces the expression of inflammatory markers and migration of inflammatory cells into the aorta of normotensive mice. Thus, angiotensin II may increase the propensity to develop a cardiovascular injury, even in normotensive individuals.

Sex differences in endothelial function important to vascular health and overall cardiovascular disease risk across the lifespan

Diseases of the cardiovascular system are the leading cause of morbidity and mortality in men and women in developed countries, and cardiovascular disease (CVD) is becoming more prevalent in developing countries. The prevalence of atherosclerotic CVD in men is greater than in women until menopause, when the prevalence of CVD increases in women until it exceeds that of men. Endothelial function is a barometer of vascular health and a predictor of atherosclerosis that may provide insights into sex differences in CVD as well as how and why the CVD risk drastically changes with menopause. Studies of sex differences in endothelial function are conflicting, with some studies showing earlier decrements in endothelial function in men compared with women, whereas others show similar age-related declines between the sexes. Because the increase in CVD risk coincides with menopause, it is generally thought that female hormones, estrogens in particular, are cardioprotective. Moreover, it is often proposed that androgens are detrimental. In truth, the relationships are more complex. This review first addresses female and male sex hormones and their receptors and how these interact with the cardiovascular system, particularly the endothelium, in healthy young women and men. Second, we address sex differences in sex steroid receptor-independent mechanisms controlling endothelial function, focusing on vascular endothelin and the renin-angiotensin systems, in healthy young women and men. Finally, we discuss sex differences in age-associated endothelial dysfunction, focusing on the role of attenuated circulating sex hormones in these effects.

Microvascular endothelial function is impaired in patients with idiopathic hyperaldosteronism

The aims were to evaluate the relationship between idiopathic hyperaldosteronism (IHA) and grade of vascular function in the macrovasculature and microvasculature. Vascular function, including reactive hyperemia index (RIH), flow-mediated vasodilation (FMD), and nitroglycerine-induced vasodilation (NID) were evaluated in 52 patients with IHA, 53 patients with aldosterone-producing adenoma (APA), and 52 age-, sex-, and blood pressure-matched patients with essential hypertension (EHT). Log RHI was lower in the IHA and APA groups than in the EHT group (0.54 ± 0.25 and 0.55 ± 0.23 versus 0.79 ± 0.28; P < 0.01, respectively). FMD was lower in the APA group than in the EHT group (3.4 ± 2.1% versus 4.8 ± 2.8%; P = 0.02), whereas there was no significant difference in FMD between the IHA and the APA and EHT groups. NID was lower in the APA group than in the EHT group (10.0 ± 4.5% versus 12.5 ± 5.7%; P = 0.03), whereas there was no significant difference in NID between the IHA, APA, and EHT groups. Multiple regression analysis revealed an association of log RHI with plasma aldosterone concentration (t = -2.24; P = 0.03) and an association of FMD with plasma aldosterone concentration (t = -3.07; P < 0.01). Microvascular endothelial function was impaired in patients with IHA compared with that in patients with EHT.

XPO1-mediated nuclear export of RNF146 protects from angiotensin II-induced endothelial cellular injury

Endothelial cells death induced by angiotensin II (Ang II) plays a role in vascular injury. RNF146 is identified as a E3 ubiquitin ligase, which promotes cell survival under many types of stresses. However, the role of RNF146 in endothelial cellular injury is unknown. In human umbilical vein endothelial cells (HUVECs), Ang II treatment led to cell death by oxidative stress and promoted RNF146 to accumulate in nucleus in time dependent manner. Nuclear export signal was found in the RNF146's sequence. The interaction between RNF146 and XPO1 was further confirmed by co-immunoprecipitation. Inhibition of XPO1 with KPT-185 increased the level of RNF146 in nucleus. The expression of XPO1 was suppressed responding to Ang II treatment. Overexpression of XPO1 facilitated the nuclear shuttling of RNF146, which protected from Ang II-induced cell death. Moreover, overexpression of RNF146 in HUVECs reduced the cell death induced by Ang II, whereas inhibition of XPO1 abolished the protective effect of RNF146. Therefore, our data demonstrated that RNF146 was a protective factor against cell death induced by AngII in human endothelial cells, which was dependent on XPO1-mediated nuclear export.

Mitochondrial oxidative stress in obesity: role of the mineralocorticoid receptor

Obesity is a multifaceted, chronic, low-grade inflammation disease characterized by excess accumulation of dysfunctional adipose tissue. It is often associated with the development of cardiovascular (CV) disorders, insulin resistance and diabetes. Under pathological conditions like in obesity, adipose tissue secretes bioactive molecules called 'adipokines', including cytokines, hormones and reactive oxygen species (ROS). There is evidence suggesting that oxidative stress, in particular, the ROS imbalance in adipose tissue, may be the mechanistic link between obesity and its associated CV and metabolic complications. Mitochondria in adipose tissue are an important source of ROS and their dysfunction contributes to the pathogenesis of obesity-related type 2 diabetes. Mitochondrial function is regulated by several factors in order to preserve mitochondria integrity and dynamics. Moreover, the renin-angiotensin-aldosterone system is over-activated in obesity. In this review, we focus on the pathophysiological role of the mineralocorticoid receptor in the adipose tissue and its contribution to obesity-associated metabolic and CV complications. More specifically, we discuss whether dysregulation of the mineralocorticoid system within the adipose tissue may be the upstream mechanism and one of the early events in the development of obesity, via induction of oxidative stress and mitochondrial dysfunction, thus impacting on systemic metabolism and the CV system.

A review of translational medicine. The future paradigm: how can we connect the orthopedic dots better?

INTRODUCTION

Patients with complex medical and surgical problems often travel great distances to prestigious university medical centers in search of solutions and in some cases for nothing more than a diagnosis of their condition. Translational medicine (TM) is an emerging method and process of facilitating medical advances efficiently from the scientist to the clinician. Most established clinicians and those in training know very little about this new discipline. The purpose of this article is to illustrate TM in varied scientific, medical and surgical fields.

MATERIALS AND METHODS

Anecdotal events in medicine and orthopaedics based upon a practicing orthopaedic surgeon's training and clinical experience are presented.

RESULTS

TM is rapidly assuming a greater presence in the medical community. The National Institute of Health (NIH) recognizes this discipline and has funded TM projects. Numerous institutions in Europe and the USA offer advanced degrees in TM. Finally there is a European Society for Translational Medicine (EUTMS), an International Society for Translational Medicine, and an Academy of Translational Medical Professionals (ATMP).

DISCUSSION

The examples of TM presented in this article support the argument for the formation of more TM networks on the local and regional levels. The need for increased participation of researchers and clinicians requires further study to identify the economic and social impact of TM.

CONCLUSIONS

The examples of TM presented in this article support the argument for the formation of more TM networks on the local and regional levels. Financial constraints for TM can be overcome by pooling government, academic, private, and industry resources in an organized fashion with oversight by a lead TM researcher.

The probable roles of valsartan in alleviating chronic obstructive pulmonary disease following co-exposure to cold stress and fine particulate matter

Angiotensin II (ANG II) might play an important role in the co-effects of cold stress and fine particulate matter (PM_2.5) on chronic obstructive pulmonary disease (COPD). The purpose of this study is to evaluate the roles of valsartan in alleviating COPD following co-exposure to cold stress and PM_2.5. Both the two intervention factors are carried out upon COPD rats with the intervention of valsartan. Blockade of angiotensin receptor by valsartan decreases the levels of malondialdehyde in the normal temperature and tumor necrosis factor-α under cold stress significantly. When treated with valsartan and PM_2.5 simultaneously, the expression of 8-hydroxy-2-deoxyguanosine, nuclear factor kappa B and heme oxygenase-1 decrease significantly in the group of cold stress. In conclusion, these results indicate that valsartan might relieve the co-effects of cold stress and PM_2.5 on COPD rat lung to some degree.

Dysregulation of the Renin-Angiotensin System and the Vasopressinergic System Interactions in Cardiovascular Disorders

Purpose of Review

In many instances, the renin-angiotensin system (RAS) and the vasopressinergic system (VPS) are jointly activated by the same stimuli and engaged in the regulation of the same processes.

Recent Findings

Angiotensin II (Ang II) and arginine vasopressin (AVP), which are the main active compounds of the RAS and the VPS, interact at several levels. Firstly, Ang II, acting on AT1 receptors (AT1R), plays a significant role in the release of AVP from vasopressinergic neurons and AVP, stimulating V1a receptors (V1aR), regulates the release of renin in the kidney. Secondly, Ang II and AVP, acting on AT1R and V1aR, respectively, exert vasoconstriction, increase cardiac contractility, stimulate the sympathoadrenal system, and elevate blood pressure. At the same time, they act antagonistically in the regulation of blood pressure by baroreflex. Thirdly, the cooperative action of Ang II acting on AT1R and AVP stimulating both V1aR and V2 receptors in the kidney is necessary for the appropriate regulation of renal blood flow and the efficient resorption of sodium and water. Furthermore, both peptides enhance the release of aldosterone and potentiate its action in the renal tubules.

Summary

In this review, we (1) point attention to the role of the cooperative action of Ang II and AVP for the regulation of blood pressure and the water-electrolyte balance under physiological conditions, (2) present the subcellular mechanisms underlying interactions of these two peptides, and (3) provide evidence that dysregulation of the cooperative action of Ang II and AVP significantly contributes to the development of disturbances in the regulation of blood pressure and the water-electrolyte balance in cardiovascular diseases.

Changes in extracellular matrix in subcutaneous small resistance arteries of patients with essential hypertension

BACKGROUND

In the development of hypertensive microvascular remodeling, a relevant role may be played by changes in extracellular matrix proteins. Aim of this study was the to evaluate some extracellular matrix components within the tunica media of subcutaneous small arteries in 9 normotensive subjects and 12 essential hypertensive patients, submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region.

PATIENTS AND METHODS

Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured. In addition, fibronectin, laminin, transforming growth factor-beta-1 (TGF-β1) and emilin-1 contents within the tunica media were evaluated by immunofluorescence and relative immunomorphometrical analysis (immunopositivity % of area). The total collagen content and collagen subtypes within the tunica media were evaluated using both Sirius red staining (under polarized light) and immunofluorescence assay.

RESULTS

Normotensive controls had less total and type III collagen in respect with hypertensive patients. Fibronectin and TGF-β1 tunica media content was significantly greater in essential hypertensive patients, compared with normotensive controls, while laminin and emilin-1 tunica media content was lesser in essential hypertensive patients, compared with normotensive controls. A significant correlation was observed between fibronectin tunica media content and media to lumen ratio.

CONCLUSIONS

Our results indicate that, in small resistance arteries of patients with essential hypertension, a relevant fibrosis may be detected; fibronectin and TGF-β1 tunica media content is increased, while laminin and emilin-1 content is decreased; these changes might be involved in the development of small resistance artery remodeling in humans.

Acute lysyl oxidase inhibition alters microvascular function in normotensive but not hypertensive men and women

The lysyl oxidase (LOX) family of enzymes regulates collagen cross-linking. LOX is upregulated in hypertension, increasing vascular stiffness. In vivo human research is sparse, as long-term LOX inhibition in animals causes vascular instability. Our aim was to evaluate the effects of LOX inhibition on cutaneous microvascular function to determine whether LOX function was upregulated in hypertensive humans. Four intradermal microdialysis fibers were placed in the forearm of 10 young [age: 24 ± 1 yr, mean arterial pressure (MAP): 87 ± 2 mmHg], 10 normotensive (age: 50 ± 2 yr, MAP: 84 ± 1 mmHg), and 10 hypertensive (age: 53 ± 2 yr, MAP: 112 ± 2 mmHg) subjects. Two sites were perfused with 10 mM β-aminopropionitrile (BAPN) to inhibit LOX. The remaining two sites were perfused with lactated Ringer solution (control). A norepinephrine dose response (10-12-10-2 M) was performed to examine receptor-mediated vasoconstrictor function. A sodium nitroprusside dose response (10-8-10-1.3 M) was performed to examine vascular smooth muscle vasodilator function. Red blood cell flux was measured via laser-Doppler flowmetry and normalized to cutaneous vascular conductance (flux/MAP). LogEC50 values were calculated to determine changes in vasosensitivity. Skin tissue samples were analyzed for both extracellular matrix-bound and soluble LOX. LOX inhibition augmented vasoconstrictor sensitivity in young (control: -6.0 and BAPN: -7.1, P = 0.03) and normotensive (control: -4.8 and BAPN: -7.0, P = 0.01) but not hypertensive (control: -6.0 and BAPN: -6.1, P = 0.79) men and women. Relative to young subjects, extracellular matrix-bound LOX expression was higher in hypertensive subjects (young: 100 ± 8 and hypertensive: 162 ± 8, P = 0.002). These results suggest that upregulated LOX may contribute to the vascular stiffness and microvascular dysfunction characteristic in hypertension. NEW & NOTEWORTHY Matrix-bound lysyl oxidase (LOX) and LOX-like 2 expression are upregulated in the microvasculature of hypertensive men and women. Microvascular responsiveness to exogenous stimuli is altered with localized LOX inhibition in healthy men and women but not hypertensive adults. The LOX family differentially affects microvascular function in hypertensive and normotensive men and women.

Atorvastatin inhibits the apoptosis of human umbilical vein endothelial cells induced by angiotensin II via the lysosomal-mitochondrial axis

This study was aimed to evaluate lysosomes-mitochondria cross-signaling in angiotensin II (Ang II)-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and whether atorvastatin played a protective role via lysosomal-mitochondrial axis. Apoptosis was detected by flow cytometry, Hoechst 33342 and AO/EB assay. The temporal relationship of lysosomal and mitochondrial permeabilization was established. Activity of Cathepsin D (CTSD) was suppressed by pharmacological and genetic approaches. Proteins production were measured by western blotting. Our study showed that Ang II could induce the apoptosis of HUVECs in a dose-depended and time-depended manner. Exposure to 1 μM Ang II for 24 h resulted in mitochondrial depolarization, cytochrome c release, and increased ROS production. Lysosomal permeabilization and CTSD redistribution into the cytoplasm occurred several hours prior to mitochondrial dysfunction. These effects were all suppressed by atorvastatin. Either pharmacological or genetic inhibition of CTSD preserved mitochondrial function and decreased apoptosis in HUVECs. Most importantly, we found that the protective effect of atorvastatin was significantly greater than pharmacological or genetic inhibition of CTSD. Finally, overexpression of CTSD without exposure to Ang II had no effect on mitochondrial function and apoptosis. Our data strongly suggested that Ang II induced apoptosis through the lysosomal-mitochondrial axis in HUVECs. Furthermore, atorvastatin played an important role in the regulation of lysosomes and mitochondria stability, resulting in an antagonistic role against Ang II on HUVECs.

Deactivation of 12(S)-HETE through (ω-1)-hydroxylation and β-oxidation in alternatively activated macrophages

Polarization of macrophages to proinflammatory M1 and to antiinflammatory alternatively activated M2 states has physiological implications in the development of experimental hypertension and other pathological conditions. 12/15-Lipoxygenase (12/15-LO) and its enzymatic products 12(S)- and 15(S)-hydroxyeicosatetraenoic acid (HETE) are essential in the process since disruption of the gene encoding 12/15-LO renders the mice unsusceptible to hypertension. The objective was to test the hypothesis that M2 macrophages catabolize 12(S)-HETE into products that are incapable of promoting vasoconstriction. Cultured M2 macrophages metabolized externally added [¹⁴C]12(S)-HETE into more polar metabolites, while M1 macrophages had little effect on the catabolism. The major metabolites were identified by mass spectrometry as (ω-1)-hydroxylation and β-oxidation products. The conversion was inhibited by both peroxisomal β-oxidation inhibitor, thioridazine, and cytochrome P450 inhibitors. Quantitative PCR analysis confirmed that several cytochrome P450 enzymes (CYP2E1 and CYP1B1) and peroxisomal β-oxidation markers were upregulated upon M2 polarization. The identified 12,19-dihydroxy-5,8,10,14-eicosatetraenoic acid and 8-hydroxy-6,10-hexadecadienoic acid metabolites were tested on abdominal aortic rings for biological activity. While 12(S)-HETE enhanced vasoconstrictions to angiotensin II from 15% to 25%, the metabolites did not. These results indicate that M2, but not M1, macrophages degrade 12(S)-HETE into products that no longer enhance the angiotensin II-induced vascular constriction, supporting a possible antihypertensive role of M2 macrophages.

New Methods to Study the Microcirculation

Essential hypertension is associated with structural alterations in the microvessels; in particular, an increase in the media thickness to internal lumen ratio of small resistance arteries (MLR) and a reduction in capillary density have been observed. The evaluation of the morphological characteristics of small resistance arteries in humans is challenging. The gold-standard method is generally considered to be the measurement by wire or pressure micromyography of MLR of subcutaneous small vessels obtained by local biopsies. However, noninvasive techniques for the evaluation of retinal arterioles were recently proposed; in particular, 2 approaches, scanning laser Doppler flowmetry (SLDF) and adaptive optics (AO), seem to provide useful information. Both of them provide an estimation of the wall to lumen ratio (WLR) of retinal arterioles. Moreover, a noninvasive measurement of basal and total capillary density may be obtained by videomicroscopy/capillaroscopy. It has been recently demonstrated that AO has a substantial advantage over SLDF in terms of evaluation of microvascular morphology, since WLR measured with AO is more closely correlated with the M/L of subcutaneous small arteries. The possibility to noninvasively assess in a reliable way, microvascular morphology in a clinical setting may represent a major advancement, since micromyography has substantial limitations in its application due to the local invasiveness of the procedure.

Atorvastatin protects the proliferative ability of human umbilical vein endothelial cells inhibited by angiotensin II by changing mitochondrial energy metabolism

This study aimed to explore whether angiotensin II (Ang II) inhibits the proliferation of human umbilical vein endothelial cells (HUVECs) by changing mitochondrial energy metabolism, and whether atorvastatin has a protective role via restoration of endothelial function. HUVECs were treated with 1 µM Ang II alone or with 10 µM atorvastatin for 24 h. Proliferation was detected by MTT assay, cell counting, 5-ethynyl-2′-deoxyuridine assay and real-time cell analyzer. Mitochondrial energy metabolism including oxygen consumption rate and extracellular acidification rate were measured using a Seahorse metabolic flux analyzer. Mitochondrial membrane potential was detected under fluorescence microscope following staining with tetramethylrhodamine. Respiratory chain complexes I–V were detected using western blotting. The current study showed that Ang II inhibits the proliferation of HUVECs. Results from the Seahorse metabolic flux analyzer indicated that Ang II decreased basal oxygen consumption, maximal respiration capacity, spare respiration capacity, adenosine triphosphate-linked respiration and non-mitochondrial respiration. By contrast, Ang II increased the proton leak. Additionally, Ang II increased glycolysis, glycolytic capacity and non-glycolytic acidification. Furthermore, these effects were all suppressed by atorvastatin. The results indicated that atorvastatin prevents cellular energy metabolism switching from oxidative phosphorylation to glycolysis induced by Ang II and protected the proliferative ability of HUVECs.

Vascular Smooth Muscle Cells and Arterial Stiffening: Relevance in Development, Aging, and Disease

The cushioning function of large arteries encompasses distension during systole and recoil during diastole which transforms pulsatile flow into a steady flow in the microcirculation. Arterial stiffness, the inverse of distensibility, has been implicated in various etiologies of chronic common and monogenic cardiovascular diseases and is a major cause of morbidity and mortality globally. The first components that contribute to arterial stiffening are extracellular matrix (ECM) proteins that support the mechanical load, while the second important components are vascular smooth muscle cells (VSMCs), which not only regulate actomyosin interactions for contraction but mediate also mechanotransduction in cell-ECM homeostasis. Eventually, VSMC plasticity and signaling in both conductance and resistance arteries are highly relevant to the physiology of normal and early vascular aging. This review summarizes current concepts of central pressure and tensile pulsatile circumferential stress as key mechanical determinants of arterial wall remodeling, cell-ECM interactions depending mainly on the architecture of cytoskeletal proteins and focal adhesion, the large/small arteries cross-talk that gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis. We further speculate on the contribution of cellular stiffness along the arterial tree to vascular wall stiffness. In addition, this review provides the latest advances in the identification of gene variants affecting arterial stiffening. Now that important hemodynamic and molecular mechanisms of arterial stiffness have been elucidated, and the complex interplay between ECM, cells, and sensors identified, further research should study their potential to halt or to reverse the development of arterial stiffness.

Microvascular structure as a prognostically relevant endpoint

Remodelling of subcutaneous small resistance arteries, as indicated by an increased media-to-lumen ratio, is frequently present in hypertensive, obese, or diabetic patients. The increased media-to-lumen ratio may impair organ flow reserve. This may be important in the maintenance and, probably, also in the progressive worsening of hypertensive disease. The presence of structural alterations represents a prognostically relevant factor, in terms of development of target organ damage or cardiovascular events, thus allowing us a prediction of complications in hypertension. In fact, media-to-lumen ratio of small arteries at baseline, and possibly their changes during treatment may have a strong prognostic significance. However, new, non-invasive techniques are needed before suggesting extensive application of the evaluation of remodelling of small arteries for the cardiovascular risk stratification in hypertensive patients. Some new techniques for the evaluation of microvascular morphology in the retina, currently under clinical investigation, seem to represent a promising and interesting future perspective. The evaluation of microvascular structure is progressively moving from bench to bedside, and it could represent, in the near future, an evaluation to be performed in all hypertensive patients, to obtain a better stratification of cardiovascular risk, and, possibly, it might be considered as an intermediate endpoint in the evaluation of the effects of antihypertensive therapy, provided that a demonstration of a prognostic value of non-invasive measures of microvascular structure is made available.

Novel bioactive peptides from enzymatic hydrolysate of Sardinelle (Sardinella aurita) muscle proteins hydrolysed by Bacillus subtilis A26 proteases

Sardinelle protein hydrolysate (SPH), prepared by treatment with Bacillus subtilis A26 proteases, was found to exhibit antibacterial, antioxidant and ACE-inhibitory activities. SPH, with a degree of hydrolysis of 4%, was fractionated by size exclusion chromatography on a Sephadex G-25 into five major fractions (F1-F5). F2, which exhibited the highest antibacterial and ACE-inhibitory activities, and F4, which exhibited the highest antibacterial and antioxidant activities, were further fractionated by reverse phase-high performance liquid chromatography (RP-HPLC) and then analysed using nano-ESI-LC-MS/MS to identify the sequences of peptides. Eight peptides were identified in the sub-fraction F2-A, nine peptides in the sub-fraction F4-B, and 45 peptides in F4-C. Identified peptides were found to share sequences with previously described bioactive peptides based on Biopep database. The results of this study suggest that SPH is a good source of natural bioactive peptides. Hence, it can be used as a potential ingredient in nutraceutical field.