Vascular Hypertrophy Research Articles

Combined Ethanol, Cocaine, Heroin and Methadone Abuse: a Deadly Mix, Review of the Literature

Background: Polysubstance use or abuse is defined as the ingestion or use of more than one drug of abuse within a defined time frame, aiming to enhance or modulate psychoactive effects, alleviate unwanted side effects of one substance and free access to different kinds of substances. Although deaths involving cocaine and other psychostimulants are increasing in many countries, it is not common in Iran due to the high price of cocaine due to a decrease in the supply chain to Iran. Case presentation: We report the case of a death due to polysubstance use. Analytical toxicology results were positive for cocaine, cocaethylene, morphine (heroin metabolite), and methadone in combination with positive blood and vitreous humor alcohol contents. The most significant histopathologic features were vascular hypertrophy, chronic myocardial ischemia, moderate to severe atherosclerosis, acute myocardial infarction, hemorrhagic pulmonary edema, diffuse alveolar collapse, micro-vesicular steatosis, focal hepatocyte necrosis, chronic hepatitis, and steatohepatitis. Discussion: polysubstance users mix drugs to reduce the negative effects of each drug. However, mixing recreational drugs is very dangerous. Pharmacokinetic and pharmacodynamics interactions in polysubstance users can produce health consequences leading to death. Conclusion: Results of this forensic case study increased attention to overdose mortality due to polydrug use.

The unexpected role of PI3-kinase gamma in pulmonary hypertension

Abstract Introduction Pulmonary hypertension (PH) is a pulmonary vascular disease that is associated with unacceptably high morbidity and mortality. PH is characterized by chronically increased pulmonary arterial pressure, increased pulmonary vascular resistance and right ventricular (RV) dysfunction and hypertrophy. Underlying mechanisms include increased proliferation and reduced apoptosis of both vascular smooth muscle cells (SMC) and endothelial cells (EC), as well as dysregulated immune responses. We have previously shown that class IA phosphatidylinositol-3-kinase (PI3K) isoforms, activated via receptor tyrosine kinases, are critically involved in the pathogenesis of PH. However, recent findings suggest that the class IB isoform PI3Kγ, which is activated downstream of G protein coupled receptors, is also important. It has been shown that PI3Kγ is involved in numerous processes that promote both vascular remodelling and maladaptive cardiac hypertrophy, including leukocyte recruitment, expression of proinflammatory chemokines and cytokines, as well as SMC and EC proliferation and survival. Therefore, the aim of our study was to investigate the role of PI3Kγ in the pathogenesis of PH. Methods The impact of PI3Kγ on the pathogenesis of PH was analysed in vivo using mice expressing a catalytically inactive form of PI3Kγ (PI3KγKD/KD) in the hypoxia-induced mouse model of PH. Mice were kept at 10%O2 (HOX) for 21 days or left under normoxic conditions (NOX). Subsequently, systolic right ventricular pressure (RVSP) was measured with a pressure catheter. RV hypertrophy was expressed as the ratio of RV weight to left ventricular + septum weight. Migration and proliferation of human pulmonary arterial SMC (hPASMC) as well as EC (hMVEC) were analysed using a PI3Kγ isoform-specific inhibitor (AS605240 [0.1; 0.3; 1μM]). Chemotaxis was determined by means of a modified Boyden chamber, and proliferation was quantified by a Bromodeoxyuridine (BrdU) incorporation assay. Results Whereas PI3Kγ inactivation had no effect on NOX animals, hypoxia led to increased RVSP and RV hypertrophy in WT animals (34.67±2.02 mmHg; 0.38±0.087) which were unexpectedly further increased in PI3KγKD/KD mice (37.67±1.3 mmHg, p=0.0104 vs. HOX WT; 0.47±0.06, p=0.0155 vs. HOX WT). Heart rate and systemic blood pressure remained unchanged. Inhibition of PI3Kγ by means of AS605240 did not affect proliferation of hPASMC and hMVEC, induced by multiple stimuli (FCS [10%], PDGF-BB [30ng/ml], or CXCL12 [100ng/ml], VEGF [50ng/ml]), respectively. However, FCS-induced migration of these cells was significantly reduced by AS605240 [0.3μM] (p<0.05). Conclusion Contrary to our expectations, the results show that kinase inactivation of PI3Kγ was not able to attenuate the pathogenesis of PH, but surprisingly led to a significant increase without critically changing cellular responses of SMC and EC. Therefore, our results indicate an unexpected protective effect of PI3Kγ on PH. Funding Acknowledgement Type of funding source: None

Potential benefits of ambulatory blood pressure monitoring in coarctation of aorta

Abstract Background Ambulatory blood pressure monitoring (ABPM) is more sensitive than resting BP assessment in detecting hypertension in patients with coarctation of aorta (COA). However, it is not known whether ABPM provides a better measure of left ventricular (LV) pressure load and LV remodeling as compared to resting BP. LV pressure overload is the lynchpin in the pathogenesis of cardiovascular mortality in COA patients, because it leads to LV remodeling, LV dysfunction and heart failure, which sets-the-stage for cardiovascular death. Therefore identifying a sensitive clinical metric that reflects LV pressure load and LV remodeling, is an important step towards optimizing antihypertensive therapy to prevent LV dysfunction and mortality. We hypothesized that ambulatory systolic BP (SBP) has better correlation with arterial load and LV remodeling indices as compared to resting SBP. Methods Our study cohort comprised of adults with isolated COA without significant residual coarctation (Doppler peak velocity ≤2.5 m/sec), aortic or mitral valve disease. All patients underwent BP measurement at rest, followed by ABPM. Arterial load (LV pressure load) was assessed using Doppler-derived effective arterial elastance index (EAI). LV remodeling was assessed using: LV mass index (LVMI), and E/e'. We divided the cohorts into 4 categories (normotensive, masked, white-coat, and overt hypertension). Results Of the 106 patients (male 69 [65%); age 39±11 years), 98 (93%) had prior COA intervention at 6±5 years. Resting SBP was 132±17, daytime ambulatory SBP was 142±16, and nighttime ambulatory SBP was 128±12 mmHg. The mean arterial load and LV remodeling indices were: EAI 3.4±0.8 mmHg/ml·m2, LVMI 106±21 g/m2, and E/e'11±4. Compared to resting SBP, ambulatory SBP had better correlation with EAI, LVMI, and E/e'. EAI, LVMI and E/e' were significantly different between hypertension categories (Figure 1). Conclusions In this study, we demonstrated that ambulatory SBP had better correlations with arterial load and LV remodeling indices as compared to resting SBP. This suggests that ambulatory SBP was a more robust metric of LV pressure overload and remodeling, and can improve detection of vascular stiffness, LV hypertrophy and elevated LV filling pressure as compared to resting SBP. The results of the current study have important clinical implications with regards to initiation and titration of antihypertensive therapy. If ABPM is used as the gold standard for diagnosis of hypertension, the masked hypertension group (who would have been misclassified as normotensive based on resting SBP alone) will qualify for antihypertensive therapy. Additionally, since ambulatory SBP had better correlation with LV remodeling indices, perhaps titration of antihypertensive therapy using ABPM will potentially reduce the risk of LV hypertrophy and dysfunction due to hypertension. Figure 1 Funding Acknowledgement Type of funding source: None

Characterization of Spontaneous Vascular Findings in the Papillary Muscles of Beagle Dogs.

Standard histology trimming practices for toxicity studies in dogs include preparation of a section of the papillary muscle associated with the left ventricular free wall-the anteriolateral or anterior muscle. In contrast, the posteromedial or posterior papillary muscle, associated with the interventricular septum, is not commonly evaluated. In humans, the posterior papillary muscle is more often affected in ischemic myocardial disease, in large part due to the absence of collateral circulation, in contrast to the anterior muscle. Due to the differential vascular supply to the papillary muscles, we sought to determine whether there is a higher incidence of spontaneous coronary vascular changes in the posterior papillary muscle versus the anterior muscle in dogs. The hearts of 30 vehicle-treated or untreated beagle dogs that were euthanized for other purposes were collected and sectioned in a consistent manner to include both papillary muscles for histologic evaluation. The posterior muscle consistently had higher incidences of intramural coronary arteries affected by vascular medial hypertrophy, medial arteriosclerosis, intimal hyperplasia, and/or disruption or loss of the internal elastic lamina. This observation may have significant implications for the evaluation and characterization of spontaneous and xenobiotic-induced cardiovascular lesions in dogs.

Abstract MP22: GRP78 Protects Against Angiotensin II-induced Protein Aggregation, Profibrotic VSMC Phenotype, And Vascular Remodeling

Arterial stiffening is a critical risk factor contributing to the development of cardiovascular disease and end organ damage. Vascular smooth muscle cell (VSMC) hypercontractility, vessel fibrosis, and proinflammatory responses are involved. The renin angiotensin system plays critical roles in the development of VSMC stiffness phenotype, as well as CVD pathophysiology. Angiotensin II (Ang II) stimulation induces these stiffness-promoting mechanisms, however, the involvement of dysfunctional proteostasis governing Ang II contribution to vascular stiffness remains underdefined. While endoplasmic reticulum (ER) stress has been implicated in the development of arterial stiffness and hypertension, it is unknown whether the protein aggregation potentially due to maladapted unfolded protein response (UPR) in VSMCs is involved. We hypothesize AngII induced ER stress initiates protein misfolding and effects VSMC stiffness phenotype. We identify a significant increase in protein aggregate size (P<0.001: from 1,000 to 4,500 pixel/aggregate) and number per cell (P<0.01: from 20 to 100 aggregate #/cell) in rat VSMCs stimulated with AngII, which is attenuated with adenoviral overexpression of resident ER chaperone, GRP78 (P<0.01: 2000 pixels/aggregate and P<0.05: 25 aggregate #/cell). Furthermore, UPRosome associated IRE1α phosphorylation induced at 3 and 6 h following AngII stimulation is reduced in GRP78 overexpressing VSMCs (P<0.05), which may contribute to reduced monocyte adhesion (P<0.001), assessed utilizing THP-1 cells. In mice, pharmacological chaperone 3-HNA reduced AngII induced vascular hypertrophy (P=0.056), cardiac perivascular fibrosis (P=0.065), and pulse propagation velocity from 0.35 m/s to 0.23 m/s (P<0.05). A trend in pre-amyloid oligomer accumulation was seen in the medial layer of thoracic aortas following 2 weeks of AngII infusion, which was reduced with 3-HNA treatment. Similar findings were investigated in a SM22α cre-GRP78 mouse model, where a trend in reduction of these parameters are also seen. Overall, GRP78 regulation over VSMC proteostasis influences vascular stiffness phenotype and therefore, these findings may elude new pharmacological intervention for arterial stiffness and aging associated CVD.

MSCs attenuate hypoxia induced pulmonary hypertension by activating P53 and NF-kB signaling pathway through TNFα secretion

Hypoxia could cause vascular smooth muscle hypertrophy, leading to high pulmonary circulation resistance, pulmonary artery (PA) pressure, even pulmonary arterial hypertension (PAH). Recent studies have demonstrated the ability of mesenchymal stem cell (MSC) to ameliorate PAH but the mechanism was controversial. In this study, we revealed that the growth rate of pulmonary artery smooth muscle cells (PASMCs) treated with hypoxia was significantly increased than normal and showed lower expression of potassium channels. However, cells co-cultured with MSC showed decreased proliferation capability and down-regulated expression of ion channel of PAMSCs. The protein array data showed that the changes of PAMSCs was substantially associated with a high level of tumor necrosis factor alpha (TNFα) secretion from MSC. We further demonstrated that TNFα rescued the cell behavior of PAMSCs through activating the expression of P53 and NF-kB and inducing cell cycle arrest by P21/CDK2/CDK4 downregulation. These findings suggested that MSCs could attenuate abnormal function of PAMSCs by TNFα secretion, which was more or less associated with the beneficial effects of MSC on improving PAH.

Reversion of cardiovascular remodelling in renovascular hypertensive 2K-1C rats by renin-angiotensin system inhibitors.

Evaluate whether the RAS dual blockade would induce additional beneficial effects on cardiovascular remodelling when compared to monotherapy in renal hypertensive two kidneys-one clip (2K-1C) rats. Hypertensive 2K-1C and normotensive (2K) rats were treated for 14days with submaximal doses of losartan (LOS), enalapril (ENA), losartan plus enalapril (LOS+ENA) or vehicle (water). Blood pressure and some parameters of cardiovascular remodelling were evaluated. Systolic blood pressure (SBP) was higher in 2K-1C (209±3mmHg, P<.05) than in 2K (113±1mmHg) rats. There was an additional effect in 2K-1C treated with LOS+ENA (153±9mmHg) on lowering SBP when compared to LOS (184±12mmHg) or ENA (177±9mmHg). None of the treatments had effect on SBP in 2K rats. In 2K-1C, cardiomyocyte hypertrophy was reduced by all treatments, although the cardiac hypertrophy indexes remained unchanged. 2K-1C aortas presented medial thickening that was partially reduced by the treatments. Intimal hyperplasia observed in 2K-1C (15.56±0.89µm vs 8.24±0.80µm) was reversed by ENA (9.52±0.45µm) or LOS+ENA (8.17±0.53µm). Collagen deposition was increased in 2K-1C hearts (1.77±0.16 vs 1.28±0.09) and aortas (8.1±0.6 vs 5.2±0.2). Treatment with LOS reduced (1.12±0.14%) and ENA (0.81±0.11%) or LOS+ENA (0.86±0.11%) additionally diminished collagen only in 2K-1C hearts. Submaximal doses of ACEi and/or ARB have inhibitory actions on cardiac remodelling and vascular hypertrophy not entirely dependent on their effects on blood pressure normalization in renovascular hypertensive rats. Combined therapy produced additional reduction in blood pressure than monotherapy despite a similar inhibition on cardiovascular remodelling.

Cratoxylum Formosum extract exhibits antihypertensive effects via suppressing the renin-angiotensin cascade in hypertensive rats

Abstract The effect of Cratoxylum Formosum (CF) extract on blood pressure and changes in vascular structure and function in hypertensive rats was studied. Rats received 40 mg/kg L-NAME and treated with CF extract or captopril or captopril + CF extract (n = 8). CF extract attenuated hypertension, enhancement of nerve-mediated contractile responses, endothelial dysfunction and oxidative stress markers and raised concentrations of nitric oxide metabolites (NOx) in L-NAME treated rats. Aortic hypertrophy associated with increases in serum ACE activity, plasma angiotensin II level, and AT1R/Akt/STAT3 protein expression in hypertensive rats were alleviated by CF extract. In hypertensive rats, captopril + CF extract administration showed greater effects on reducing blood pressure and vascular hypertrophy. Data of this study suggested that an antihypertensive effect of CF extract is linked to its antioxidant effect to enhance NO bioavailability and an inhibitory effect on RAS cascade.

TNF-α inhibition decreases MMP-2 activity, reactive oxygen species formation and improves hypertensive vascular hypertrophy independent of its effects on blood pressure

Systemic arterial hypertension is a public health problem associated with an increased risk of cardiovascular disease. Matrix metalloproteinases (MMP) are endopeptidases that participate in hypertension-induced cardiovascular remodeling, which may be activated by oxidative stress. Angiotensin II (Ang II), a potent hypertrophic and vasoconstrictor peptide, increases oxidative stress, MMP-2 activity and tumor necrosis factor (TNF-α) expression. In vitro studies have shown that TNF-α is essential for Ang II-induced MMP-2 expression. Thus, this study evaluated whetherTNF-α inhibition decreases the development of hypertension-induced vascular remodeling via reduction of MMP-2 activity and reactive oxygen species (ROS) formation. Two distinct pharmacological approaches were used in the present study: Pentoxifylline (PTX), a non-selective inhibitor of phosphodiesterases that exerts anti- inflammatory effects via inhibition of TNF-α, and Etanercept (ETN), a selective TNF-α inhibitor. 2-kidney and 1-Clip (2K1C). 2-kidney and 1-Clip (2K1C) and Sham rats were treated with Vehicle, PTX (50 mg/Kg and 100 mg/kg daily) or ETN (0.3 mg/Kg and 1 mg/kg; three times per week). Systolic blood pressure (SBP) was measured weekly by tail cuff plethysmography. Plasma TNF-α and IL-1β levels were evaluated by enzyme-linked immunosorbent assay (ELISA) technique. The vascular hypertrophy was examined in the aorta sections stained with hematoxylin/eosin. ROS in aortas was evaluated by dihydroethidium and chemiluminescence lucigenin assay. Aortic MMP-2 levels and activity were evaluated by gel zymography and in situ zymography, respectively. The 2K1C animals showed a progressive increase in SBP levels and was accompanied by significant vascular hypertrophy (p < 0.05 vs Sham). Treatment with PTX at higher doses decreased SBP and vascular remodeling in 2K1C animals (p < 0.05 vs 2K1C vehicle). Although the highest dose of ETN treatment did not reduce blood pressure, the vascular hypertrophy was significantly attenuated in 2K1C animals treated with ETN1 (p < 0.05). The increased cytokine levels and ROS formation were reversed by the highest doses of both PTX and ETN. The increase in MMP-2 levels and activity in 2K1C animals were reduced by PTX100 and ETN1 treatments (p < 0.05 vs vehicle 2K1C). Lower doses of PTX and ETN did not affect any of the evaluated parameters in this study, except for a small reduction in TNF-α levels. The findings of the present study suggest that PTX and ETN treatment exerts immunomodulatory effects, blunted excessive ROS formation, and decreased renovascular hypertension-induced MMP-2 up-regulation, leading to improvement ofvascular remodeling typically found in 2K1C hypertension. Therefore, strategies using anti-hypertensive drugs in combination with TNF alpha inhibitors could be an attractive therapeutic approach to tackle hypertension and its associated vascular remodeling.

Cerebrovascular reactivity: a new frontier for measuring cognitive health in models of accelerated ageing?

Cerebrovascular reactivity: a new frontier for measuring cognitive health in models of accelerated ageing?

Non-invasive evaluation of retinal vascular remodeling and hypertrophy in humans: intricate effect of ageing, blood pressure and glycaemia.

Ageing, hypertension and diabetes have an intricate effect on microvascular structure. In the retina, the respective contribution of remodeling and hypertrophy in such process is still unclear. We aimed at disentangling age, blood pressure and glycaemia effects onretinal microcirculation using the non-invasive adaptive optics ophthalmoscopy (AOO). We included 429 subjects, distributed into 4 groups according to normal (nBP) or high blood pressure (hBP) and/or normal (nGly) or high fasting glycaemia (hGly). The nBP/nGly group was stratified in age tertiles to isolate theeffect of ageing. AOO was used to measure arteriolar wall thickness (WT, µm), arteriolar (aID, µm) and venular internal diameter (vID, µm) and calculate arteriolar wall-to-lumen ratio (WLR), wall cross-sectional area (WCSA, µm2). One-way ANOVA for parametric variables and Kruskal-Wallis test for non-parametric variables were used for comparison among groups. A multivariate regression analysis including age, gender, BP, hGly and antihypertensive treatment was performed to calculate independent predictors of retinal remodeling. WT was increased with ageing (tertile1: 22.5 ± 3.2, tertile2: 24.2 ± 3.5, tertile 3: 25.2 ± 3.8, p = 0.001) and BP (hBP: 25.2 ± 4.1 vs nBP: 23.9 ± 3.7, p = 0.003). aID decreased with BP (hBP: 90.2 ± 13.4 vs nBP: 93.6 ± 11.6, p = 0.013) and increased with glycaemia (hGly: 97.7 ± 12.5 vs nGly: 93.6 ± 11.6, p = 0.002). Amultivariate analysis showed independent association of hBPwithWLR; hGly withWCSA; ageing with WLR and WCSA. AOO non-invasively identifies retinal structural changes in human confirming that microvascular remodeling is exclusively related to hypertension, whereas vascular growth is related to ageing and hyperglycaemia.

Pro-Senescence and Anti-Senescence Mechanisms of Cardiovascular Aging: Cardiac MicroRNA Regulation of Longevity Drug-Induced Autophagy.

Chronological aging as well as biological aging accelerated by various pathologies such as diabetes and obesity contribute to cardiovascular aging, and structural and functional tissue damage of the heart and vasculature. Cardiovascular aging in humans is characterized by structural pathologic remodeling including cardiac and vascular fibrosis, hypertrophy, stiffness, micro- and macro-circulatory impairment, left ventricular diastolic dysfunction precipitating heart failure with either reduced or preserved ejection fraction, and cardiovascular cell death. Cellular senescence, an important hallmark of aging, is a critical factor that impairs repair and regeneration of damaged cells in cardiovascular tissues whereas autophagy, an intracellular catabolic process is an essential inherent mechanism that removes senescent cells throughout life time in all tissues. Several recent reviews have highlighted the fact that all longevity treatment paradigms to mitigate progression of aging-related pathologies converge in induction of autophagy, activation of AMP kinase (AMPK) and Sirtuin pathway, and inhibition of mechanistic target of rapamycin (mTOR). These longevity treatments include health style changes such as caloric restriction, and drug treatments using rapamycin, the first FDA-approved longevity drug, as well as other experimental longevity drugs such as metformin, rapamycin, aspirin, and resveratrol. However, in the heart tissue, autophagy induction has to be tightly regulated since evidence show excessive autophagy results in cardiomyopathy and heart failure. Here we discuss emerging evidence for microRNA-mediated tight regulation of autophagy in the heart in response to treatment with rapamycin, and novel approaches to monitor autophagy progression in a temporal manner to diagnose and regulate autophagy induction by longevity treatments.

Molecular Mechanisms of Adiponectin-Induced Attenuation of Mechanical Stretch-Mediated Vascular Remodeling.

Hypertension induces vascular hypertrophy, which changes blood vessels structurally and functionally, leading to reduced tissue perfusion and further hypertension. It is also associated with dysregulated levels of the circulating adipokines leptin and adiponectin (APN). Leptin is an obesity-associated hormone that promotes vascular smooth muscle cell (VSMC) hypertrophy. APN is a cardioprotective hormone that has been shown to attenuate hypertrophic cardiomyopathy. In this study, we investigated the molecular mechanisms of hypertension-induced VSMC remodeling and the involvement of leptin and APN in this process. To mimic hypertension, the rat portal vein (RPV) was mechanically stretched, and the protective effects of APN on mechanical stretch-induced vascular remodeling and the molecular mechanisms involved were examined by using 10 μg/ml APN. Mechanically stretching the RPV significantly decreased APN protein expression after 24 hours and APN mRNA expression in a time-dependent manner in VSMCs. The mRNA expression of the APN receptors AdipoR1, AdipoR2, and T-cadherin significantly increased after 15 hours of stretch. The ratio of APN/leptin expression in VSMCs significantly decreased after 24 hours of mechanical stretch. Stretching the RPV for 3 days increased the weight and [3H]-leucine incorporation significantly, whereas APN significantly reduced hypertrophy in mechanically stretched vessels. Stretching the RPV for 10 minutes significantly decreased phosphorylation of LKB1, AMPK, and eNOS, while APN significantly increased p-LKB1, p-AMPK, and p-eNOS in stretched vessels. Mechanical stretch significantly increased p-ERK1/2 after 10 minutes, whereas APN significantly reduced stretch-induced ERK1/2 phosphorylation. Stretching the RPV also significantly increased ROS generation after 1 hour, whereas APN significantly decreased mechanical stretch-induced ROS production. Exogenous leptin (3.1 nM) markedly increased GATA-4 nuclear translocation in VSMCs, whereas APN significantly attenuated leptin-induced GATA-4 nuclear translocation. Our results decipher molecular mechanisms of APN-induced attenuation of mechanical stretch-mediated vascular hypertrophy, with the promising potential of ultimately translating this protective hormone into the clinic.

Downregulation of the GLP-1/CREB/adiponectin pathway is partially responsible for diabetes-induced dysregulated vascular tone and VSMC dysfunction

BackgroundThe dysfunction of vasculature is observed in diabetes and might be responsible for the increased incidence of vascular events. Previous studies indicated that supplementation of GLP-1 analogues is beneficial to the cardiovascular functions in diabetic patients, but the mechanisms are not clear. MethodsA type 1 diabetic model was constructed. Vascular constrictions were measured using wire myograph. Western blotting and quantitative PCR were adopted to analyze the expression profiles of key molecules. Mitochondrial functions were analyzed in both vascular tissues or vascular smooth muscle cells (VSMCs). Dual-luciferase reporter assay was used to investigate the mechanism of adiponectin regulation. ResultsIn this study, abnormal vascular hypertrophy and increased vascular tones were observed in both diabetic patients and animals. ROS productions were increased in vessels and VSMCs from diabetic patients and animals, and the ROS scavenger mitoTEMPO partially attenuated the abnormal vascular tones and hypertension. In addition, decreased GLP-1 levels were observed, while GLP-1 supplementation improved the mitochondrial functions and vascular tones. Furthermore, it was shown that GLP-1 supplementation enhanced adiponectin expressions, while adiponectin facilitated the phosphorylation of AMPK and Sirt1 expressions. Also, CREB phosphorylation was enhanced upon GLP-1 supplementation and promoted the transcriptions of adiponectin. Finally, CREB inhibition partially attenuated the effects of GLP-1 on mitochondrial functions and adiponectin expressions. ConclusionGLP-1 downregulation might be an important mechanism of abnormal mitochondrial function and vascular tone in diabetes. Targeting GLP-1/CREB/adiponectin axis might become a promising therapeutic strategy in alleviating diabetes-related cardiovascular dysfunctions.

Calcitonin gene-related peptide inhibits angiotensin II-induced NADPH oxidase-dependent ROS via the Src/STAT3 signalling pathway.

We had previously demonstrated that the calcitonin gene‐related peptide (CGRP) suppresses the oxidative stress and vascular smooth muscle cell (VSMC) proliferation induced by vascular injury. A recent study also indicated that CGRP protects against the onset and development of angiotensin II (Ang II)‐induced hypertension, vascular hypertrophy and oxidative stress. However, the mechanism behind the effects of CGRP on Ang II‐induced oxidative stress is unclear. CGRP significantly suppressed the level of reactive oxygen species (ROS) generated by NADPH oxidase in Ang II‐induced VSMCs. The Ang II‐stimulated activation of both Src and the downstream transcription factor, STAT3, was abrogated by CGRP. However, the antioxidative effect of CGRP was lost following the expression of constitutively activated Src or STAT3. Pre‐treatment with H‐89 or CGRP8–37 also blocked the CGRP inhibitory effects against Ang II‐induced oxidative stress. Additionally, both in vitro and in vivo analyses show that CGRP treatment inhibited Ang II‐induced VSMC proliferation and hypertrophy, accompanied by a reduction in ROS generation. Collectively, these results demonstrate that CGRP exhibits its antioxidative effect by blocking the Src/STAT3 signalling pathway that is associated with Ang II‐induced VSMC hypertrophy and hyperplasia.

Adiponectin Reduces Angiotensin II‐Induced Vascular Hypertrophy by Targeting ROS Formation and Actin Cytoskeleton Remodeling

Background and aimsAdiponectin (APN), an adipocytokine, exerts cardioprotective effects, while angiotensin II (Ang II) plays a critical role in the pathogenesis of hypertrophy of vascular smooth muscle cells (VSMCs) induces hypertension and vascular remodeling. Ang II induces VSMC hypertrophy in part via activation of RhoA/ROCK pathway. In this study, we investigated the molecular mechanisms associated with Ang II‐induced RhoA activation and translocation and the ability of ANP to counteract Ang II‐hypertrophic effect through inhibition of RhoA activation, actin cytoskeleton remolding and reactive oxygen species (ROS) formation.MethodsStudies were carried out using rat aortic tissues and VSMCs. The effect of APN on Ang II‐induced RhoA translocation was assessed by Western blotting (WB) and Immunohistochemistry. Leucine incorporation was used to examine NO effect on Ang II induced hypertrophy. The phosphorylation of cofilin‐2 and ERK1/2 was detected by WB. Moreover, immunohistochemistry was performed on aortic frozen sections to detect ROS, F‐actin and G‐actin levels, RhoA‐Cav 1 co‐localization and eNOS translocation.ResultsAng II‐induced VSMCs hypertrophy was prevented by supplementing APN. The hypertrophic response to Ang II was associated with RhoA translocation to caveolae‐rich membrane, cofilin‐2 and ERK1/2 phosphorylation, in addition to a significant decrease in G/F actin ratio. Moreover, ROS production significantly increased with Ang II treatment as revealed by confocal microscopy. However, these effects were inhibited by APN and caveolae disruption. Taken together, these results suggest that Ang II hypertrophic effect is due, in part, to RhoA translocation to caveolae rich micro‐domains and its downstream effectors which is counteracted by APN.ConclusionThese findings suggest the ability of APN to attenuate Angiotensin II‐induced vascular hypertrophy.

Investigation of Analgesic Minimum Effective Dose of Apelin‐13 With Different Doses of Intraperitoneal Injections and its Effects on Kidney Tissue

Background and AimsApelin and APJ form a signaling pathway and are widely expressed in a variety of tissues including the heart, kidney and vessels. Apelin and APJ have various effects in many systems such as regulation of blood pressure and vascular tone, cardiac contractility, nociception, heart rate, apoptosis, inflammation. Apelin‐13 has a potential analgesic and proanalgesic effect, although the sites of analgesic effects are uncertain and controversial in terms of results. The fact that apelin can be used as a protective and therapeutic agent in the future will make important contributions both for human health and economically. The aim of the study is to investigate the analgesic minimum effective dose of Apelin‐13 with different doses of intraperitoneal application and its effects on kidney tissue.MethodsThirty Wistar Albino male rats were randomly divided into 5 groups. Rats were designated as control, Apelin‐25, Apelin‐50, Apelin‐100 and Apelin‐200 groups. Apelin‐13 was administered intraperitoneally at 25, 50, 100 and 200 μg/kg doses. The same volume of saline was administered intraperitoneally to the control group. Hot plate test was performed to evaluate analgesic efficacy at 0 and 30 minutes, 1 and 2 hours after administration. All rats were euthanized 24 hours after administration by intraperitoneal ketamine 100 mg/kg. Renal tissues were removed without traumatization and sent to the laboratory for evaluation of histological and oxidant status.ResultsIn the hot plate test, application of apelin 50 μg/kg and above had significantly more analgesic effects than the control group. 25 μg/kg apelin application was found to have no analgesic effect. When kidney tissues were examined, at the doses of 200 μg/kg Apelin; vascular vacuolization and hypertrophy, bowman dilatation and tubular cell shedding were significantly increased but not at the control group, 25 and 50 μg/kg Apelin groups (Figure 1– 2). When the oxidative status was evaluated with TAS and TOS, 200 μg/kg Apelin increased the oxidant parameters while reducing the antioxidant parameters. There was no significant change below this dose. It was also correlated with histopathological findings.ConclusionThat seems to be the first study on the analgesic effects of apelin in different doses in the literatüre and 50 μg/kg apelin is the minimum analgesic effective dose. The administration of 200 μg/kg apelin‐13 adversely affected kidney tissue histologically and tissue oxidative stress parameters increase by the high doses. Other aspects of these findings, including clinical significance and practical applications, merit further experimental and clinical investigation.Support or Funding InformationThis study was conducted in the GUDAM Laboratory of Gazi University with the consent of Experimental Animals Ethics Committee of Gazi University with the code G.U.ET‐19.024. The study was supported by Gazi University Scientific Research Committee (Scientific Research Project No. 01/2019‐44).Control group, renal tissue (10X H&amp;E)Figure 1200 μg/kg application of Apelin 13 increased vascular vacuolization and hypertrophy, bowman dilatation and tubular cell shedding (10X H&amp;E)Figure 2

Role of Histone Deacetylases 5 (HDAC5) in Ang II‐Induced the Early Growth Response Protein‐1 (Egr‐1) Expression and Vascular Hypertrophy

Angiotensin II (Ang II), a key vasoactive peptide, is known to play an important role in the pathophysiology of vascular diseases. A heightened activation of Ang II‐induced signaling pathways that promote proliferation, hypertrophy and migration of vascular smooth muscle cells (VSMCs) has been suggested to contribute to vascular dysfunctions. We have shown earlier that Ang II enhances the expression of early growth response protein‐1 (Egr‐1), a zinc transcription factor, which is upregulated in animal models of vascular diseases. Histone deacetylases (HDACs) remove acetyl groups of lysine residues from histone and non‐histone proteins and elevated activation of class IIa HDACs is reported in several vascular pathologies. Recent studies have demonstrated that the phosphorylation and the nuclear export of HDAC5, a member of class IIa HDACs, is associated with vascular remodeling through their ability to interact with transcription factors linked to cell proliferation, migration and hypertrophy. However, the involvement of HDAC5 in Ang II‐induced Egr‐1 expression remain unexplored. Here, we showed that the specific pharmacological inhibition of class IIa HDACs by MC1568 or TMP‐195 as well as siRNA‐mediated silencing of HDAC5 attenuated Ang II induced Egr‐1 expression in VSMCs. In addition, the blockade of the nuclear export of HDAC5 by using nuclear transport inhibitors leptomycin B or KPT‐330 decreased Ang II‐induced Egr‐1 expression. We also demonstrated that siRNA‐induced silencing of HDAC5 or Egr‐1 prevented VSMC hypertrophy in response to Ang II stimulation. In summary, our results show that Ang II‐induced Egr‐1 expression is regulated by the activation of HDAC5 and Ang II‐induced cell hypertrophy is mediated by HDAC5 and Egr‐1.Support or Funding InformationSupported by the Canadian Institutes of Health Research

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.

Tumor Necrosis Factor Alpha Deficiency Improves Endothelial Function and Cardiovascular Injury in Deoxycorticosterone Acetate/Salt-Hypertensive Mice.

It has been shown that the inflammatory cytokine tumor necrosis factor α (TNFα) plays a role in the development of hypertension and end-stage renal diseases. We hypothesize that TNFα contributes to endothelial dysfunction and cardiac and vascular injury in deoxycorticosterone acetate (DOCA)/salt-hypertensive mice. The wild-type or TNFα-deficient mice were uninephrectomized and implanted with DOCA pellet treatment for 5 weeks; the mice were given either tap water or 1% NaCl drinking water. DOCA mice developed hypertension (systolic blood pressure (SBP): 167 ± 5 vs. 110 ± 4 mmHg in control group, p < 0.05), cardiac and vascular hypertrophy, and the impairment of endothelium-dependent relaxation to acetylcholine (EDR). TNFα deficiency improved EDR and lowered cardiac and vascular hypertrophy with a mild reduction in SBP (152 ± 4 vs. 167 ± 5 mmHg in DOCA group, p < 0.05) in DOCA mice. The mRNA expressions of the inflammatory cytokines, including TNFα, interleukin 1β (IL1β), monocyte chemotactic protein 1 (MCP1), and monocyte/macrophage marker F4/80 were significantly increased in the aorta of DOCA-hypertensive mice; TNFα deficiency reduced these inflammatory gene expressions. DOCA-hypertensive mice also exhibited an increase in the vascular oxidative fluorescence intensities, the protein expressions of gp91phox and p22phox, and the fibrotic factors transforming growth factor β and fibronectin. TNFα deficiency reduced oxidative stress and fibrotic protein expressions. The DOCA mice also showed a decrease in the protein expression of eNOS associated with increased miR155 expression; TNFα deficiency prevented a decrease in eNOS expression and an increase in miR155 expression in DOCA mice. These results support the idea that TNFα significantly contributes to vascular inflammation, vascular dysfunction, and injury in hypertension.