Vascular Hypertrophy Research Articles

The cofilin phosphatase slingshot homolog 1 restrains angiotensin II-induced vascular hypertrophy and fibrosis in vivo

The dual specificity phosphatase slingshot homolog 1 (SSH1) contributes to actin remodeling by dephosphorylating and activating the actin-severing protein cofilin. The reorganization of the actin cytoskeleton has been implicated in chronic hypertension and the subsequent mechano-adaptive rearrangement of vessel wall components. Therefore, using a novel Ssh1−/− mouse model, we investigated the potential role of SSH1 in angiotensin II (Ang II)-induced hypertension, and vascular remodeling. We found that loss of SSH1 did not produce overt phenotypic changes and that baseline blood pressures as well as heart rates were comparable between Ssh1+/+ and Ssh1−/− mice. Although 14 days of Ang II treatment equally increased systolic blood pressure in both genotypes, histological assessment of aortic samples indicated that medial thickening was exacerbated by the loss of SSH1. Consequently, reverse-transcription quantitative PCR analysis of the transcripts from Ang II-infused animals confirmed increased aortic expression levels of fibronectin, and osteopontin in Ssh1−/− when compared to wild-type mice. Mechanistically, our data suggest that fibrosis in SSH1-deficient mice occurs by a process that involves aberrant responses to Ang II-induced TGFβ1. Taken together, our work indicates that Ang II-dependent fibrotic gene expression and vascular remodeling, but not the Ang II-induced pressor response, are modulated by SSH1-mediated signaling pathways and SSH1 activity is protective against Ang II-induced remodeling in the vasculature.

Cardiovascular Risk and Condition of Target-organs in Patients of Various Ages with Hypertension and High Normal or Low Normal Levels TSH

Тhe significant prevalence of arterial hypertension and thyroid diseases in the Ukrainian population determines their comorbidity and the need for studying of possible effects of functional thyroid gland state on cardiovascular risk factors and target organs damage in patients with arterial hypertension.The objective: to identify the cardiovascular risk factors and target-organs state in patients of middle – and elderly-age with arterial hypertension at high normal and low normal level TSH.Materials and methods. The above group was compared with the group of patients with hypertension and subclinical hypothyroidism. The study involved 123 patients from 45 to 75 years old with essential hypertension 1–2 grade and TSH levels within 0,4–9,9 mU/l. They were divided into groups according to TSH levels and age. Methods of research: anthropometry, measurement of blood pressure; blood test for TTG , FT4, FT3, lipids level, glucose level, creatinine; echocardiography, ultrasound study of carotid arteries.Results. The elderly patients with high normal level TSH was found more frequency cardiovascular risk factors and lesions target-organs (dislipidemia, hypertrophy LV, vascular hypertrophy or asymptomatic atherosclerosis, impairment glucose tolerance) compared with patients low normal level TSH.Conclusion. The incidence of disturbances did not differ elderly patients with high normal level TSH that patients with subclinical hypothyroidism. So high normal level TSH in elderly patients with hypertension associated the increase cardiovascular risk factors. Such patients require careful monitoring of lipid and carbohydrate metabolism, thyroid function for the timely specific correction.

Crosstalk Between Mitochondrial Hyperacetylation and Oxidative Stress in Vascular Dysfunction and Hypertension.

Significance: Vascular dysfunction plays a key role in the development of arteriosclerosis, heart disease, and hypertension, which causes one-third of deaths worldwide. Vascular oxidative stress and metabolic disorders contribute to vascular dysfunction, leading to impaired vasorelaxation, vascular hypertrophy, fibrosis, and aortic stiffening. Mitochondria are critical in the regulation of metabolic and antioxidant functions; therefore, mitochondria-targeted treatments could be beneficial. Recent Advances: Vascular dysfunction is crucial in hypertension pathophysiology and exhibits bidirectional relationship. Metabolic disorders and oxidative stress contribute to the pathogenesis of vascular dysfunction and hypertension, which are associated with mitochondrial impairment and hyperacetylation. Mitochondrial deacetylase Sirtuin 3 (Sirt3) is critical in the regulation of metabolic and antioxidant functions. Clinical studies show that cardiovascular disease risk factors reduce Sirt3 level and Sirt3 declines with age, paralleling the increased incidence of cardiovascular disease and hypertension. An imbalance between mitochondrial acetylation and reduced Sirt3 activity contributes to mitochondrial dysfunction and oxidative stress. We propose that mitochondrial hyperacetylation drives a vicious cycle between metabolic disorders and mitochondrial oxidative stress, promoting vascular dysfunction and hypertension. Critical Issues: The mechanisms of mitochondrial dysfunction are still obscure in human hypertension. Mitochondrial hyperacetylation and oxidative stress contribute to mitochondrial dysfunction; however, regulation of mitochondrial acetylation, the role of GCN5L1 (acetyl-CoA-binding protein promoting acetyltransferase protein acetylation) acetyltransferase, Sirt3 deacetylase, and acetylation of specific proteins require further investigations. Future Directions: There is an urgent need to define molecular mechanisms and the pathophysiological role of mitochondrial hyperacetylation, identify novel pharmacological targets, and develop therapeutic approaches to reduce this phenomenon.

Transactivation domain of Krüppel-like factor 15 negatively regulates angiotensin II-induced adventitial inflammation and fibrosis.

Krüppel-like factor (KLF) 15 has emerged as a critical regulator of fibrosis in cardiovascular diseases. However, the precise role that KLF15 and its functional domain played in adventitial inflammation and fibrosis remains unclear. This study aims to investigate the role of the transactivation domain (TAD) of KLF15 in angiotensin II (Ang II)-induced adventitial pathologic changes. KLF15 expression was decreased in the vascular adventitia of Ang II-infused mice (1000 ng/kg/min, 14 d) and in adventitial fibroblasts (AFs) stimulated by Ang II (10-7 M). Adenovirus-mediated KLF15 overexpression normalized Ang II-induced vascular hypertrophy, increased collagen deposition, macrophage infiltration, and CCL2 and VCAM-1 expression. Interestingly, KLF15-ΔTAD (KLF15 with deletion of TAD at amino acids 132-152) overexpression showed no effect on the above pathologic changes. Similarly, perivascularly overexpression of KLF15 but not KLF15-ΔTAD in carotid arteries also attenuated Ang II-induced vascular inflammation and fibrosis. Furthermore, KLF15 overexpression after Ang II infusion rescued Ang II-induced vascular remodeling. CCL2 or VCAM-1-mediated monocyte and macrophage migration or adhesion to AFs in response to Ang II was negatively regulated by KLF15 through TAD. Ang II-enhanced Smad2/3 activation and adventitial migration, proliferation, and differentiation of AFs were suppressed by KLF15 but not KLF15-ΔTAD overexpression. Conversely, small interfering RNA knockdown of KLF15 aggravated Ang II-induced Smad2/3 activation and dysfunction of AFs. Luciferase, coimmunoprecipitation, and chromatin immunoprecipitation assay were used to demonstrate that interaction of KLF15 with Smad2/3 suppressed CCL2 expression through TAD. Mechanistically, activation of Ang II type 1 receptor/phospholipase Cγ 1/ERK1/2 signaling resulted in a decrease of KLF15 expression. In conclusion, these results demonstrate that KLF15 negatively regulates activation of AFs through TAD, which plays an important role in Ang II-induced adventitial inflammation and fibrosis.-Lu, Y.-Y., Li, X.-D., Zhou, H.-D., Shao, S., He, S., Hong, M.-N., Liu, J.-C., Xu, Y.-L., Wu, Y.-J., Zhu, D.-L., Wang, J.-G., Gao, P.-J. Transactivation domain of Krüppel-like factor 15 negatively regulates angiotensin II-induced adventitial inflammation and fibrosis.

Histone deacetylase inhibitor LMK235 attenuates vascular constriction and aortic remodelling in hypertension.

Here, we report that LMK235, a class I and histone deacetylase (HDAC6)‐preferential HDAC inhibitor, reduces hypertension via inhibition of vascular contraction and vessel hypertrophy. Angiotensin II‐infusion mice and spontaneously hypertensive rats (SHRs) were used to test the anti‐hypertensive effect of LMK235. Daily injection of LMK235 lowered angiotensin II‐induced systolic blood pressure (BP). A reduction in systolic BP in SHRs was observed on the second day when SHRs were treated with 3 mg/kg LMK235 every 3 days. However, LMK235 treatment did not affect angiotensin‐converting enzyme 1 and angiotensin II receptor mRNA expression in either hypertensive model. LMK235, acting via the nitric oxide pathway, facilitated the relaxing of vascular contractions induced by a thromboxane A2 agonist in the rat aortic and mesenteric artery ring test. In addition, LMK235 increased nitric oxide production in HUVECs and inhibited the increasing of aortic wall thickness in both animal hypertensive models. LMK235 decreased the enhanced cell cycle‐related genes cyclin D1 and E2F3 in angiotensin II‐infusion mice and restored the decreased p21 expression. In addition, LMK235 suppressed calcium calmodulin‐dependent protein kinase II (CaMKII) α, which is related to vascular smooth muscle cell proliferation. Inhibition or knockdown of HDAC5 blocked the CaMKIIα‐induced cell cycle gene expression. Immunoprecipitation demonstrated that class I HDACs were involved in the inhibition of CaMKII α‐induced HDAC4/5 by LMK235. We suggest that LMK235 should be further investigated for its use in the development of new therapeutic options to treat hypertension via reducing vascular hyperplasia or vasoconstriction.

2018 AHA Late-Breaking Basic Science Abstracts.

2018 AHA Late-Breaking Basic Science Abstracts.

53 - Pentoxifylline treatment decreases MMP-2 activity, oxidative stress and vascular hypertrophy in renovascular hypertension

Introduction Matrix metalloproteinases (MMP) contributes to hypertensive vascular remodeling. Angiotensin II and tumoral necrose factor (TNF)-α are involved in reactive oxygen species (ROS) formation, which is responsible for in vitro MMP-2 activation. Pentoxifylline (PTX), a non-selective inhibitor of phosphodiesterases, has been reported to possess antioxidants and anti-inflammatory effects. Thus, we hypothesized that PTX decreases vascular hypertrophy in 2-kidney and 1-Clip (2K1C) rats through reduction of TNF-α, oxidative stress and MMP-2 activity. Etanercept (ETN), an TNF-α inhibitor, was used as the positive control in this study. Methods Male 2K1C and Sham rats were treated with Vehicle, PTX (100mg/Kg/day) or ETN 0.3 mg/Kg (three times/week). Systolic blood pressure (SBP) was measured weekly by tail cuff plethysmography. Vascular hypertrohy were examined in aortas sections stained with hematoxylin/eosin. Aortic MMP-2 levels and gelatinolytic activity were determined using gelatin and in situ zymography assays, respectively. Vascular oxidative stress was evaluated using dihydroethidium (DHE). TNF-α levels were analyzed using the enzyme-linked immunosorbent assay (ELISA). ResuIts 2K1C rats exhibited high SBP (191±4 mmHg vs Sham) and significant vascular hypertrophy when compared to Sham group (p 0.05). MMP-2 levels and activity were augmented in 2K1C rats when compared to sham group (p Conclusion PTX but not Etanercept treatment, ameliorates high blood pressure, vascular remodeling, oxidative stress and elevated MMP-2 activity in 2K1C rats. Financial support: FAPESP.

Topical inhibition of PUMA signaling mitigates radiation injury.

Radiation therapy is an effective treatment strategy for many types of cancer but is limited by its side effects on normal tissues, particularly the skin, where persistent and progressive fibrotic changes occur and can impair wound healing. In this study, we attempted to mitigate the effects of irradiation on skin using a novel transcutaneous topical delivery system to locally inhibit p53 up-regulated modulator of apoptosis (PUMA) gene expression with small interfering RNA (siRNA). In an isolated skin irradiation model, the dorsal skin of C57 wild-type mice was irradiated. Prior to irradiation, PUMA and nonsense siRNA were applied via a novel hydrogel formulation to dorsal skin and reapplied weekly. Skin was harvested at multiple time points to evaluate dermal siRNA penetration, mRNA expression, protein expression, dermal thickness, subcutaneous fat, stiffness, vascular hypertrophy, SCAR index, and reactive oxygen species (ROS) generation. Murine skin treated with topical PUMA siRNA via optimized hydrogel formulation demonstrated effective PUMA inhibition in irradiated tissue at 3-4 days. Tissue stiffness, dermal thickness, vascular hypertrophy, SCAR index, ROS levels, and mRNA levels of MnSOD and TGF-β were all significantly reduced with siPUMA treatment compared to nonsense controls. Subcutaneous fat area was significantly increased, and levels of SMAD3 and Phospho-SMAD3 expression were unchanged. These results show that PUMA expression can be effectively silenced in vivo using a novel hydrogel lipoplex topical delivery system. Moreover, cutaneous PUMA inhibition mitigates radiation induced changes in tissue character, restoring a near-normal phenotype independent of SMAD3 signaling.

Radiological Aspect of Klippel-Trénaunay Syndrome: A Case Series With Review of Literature.

Klippel-Trénaunay syndrome (KTS) is a rare angio-osteo-hypertrophic syndrome characterized by vascular malformations, soft tissue and/or bone hypertrophy, and varicose veins. For the purpose of describing the imaging findings and elucidating the role of medical imaging in the diagnosis and assessment of patient with KTS, we have reviewed the imaging data of 14 KTS patients. The imaging features on different imaging modalities were analyzed. Unilateral lower limb involvement was evident in 71% of cases (n=10) and bilateral but asymmetric lower limb involvement in the remaining 29% of cases (n=4). The most commonly depicted imaging features were varicosities in 93% (n=13), muscle hypertrophy in 79% (n=11) and venous anomalies in 64% (n=9). Other less common imaging findings included lymphedema in 29% (n=4), arterial malformations 29% (n=4), soft tissue hemangiomas 21% (n=3), pelvic and thigh phleboliths 21% (n=3), venous aneurysms 21% (n=3), bone abnormalities 14% (n=2) and lymphadenopathy 14% (n=2). A severe unilateral lower limb deformity resulting in contractures and muscle atrophy of the whole limb was depicted in 1 case. The pathognomonic marginal vein of Servelle was identified in 2 cases. AV shunt was highly suspected in 4 cases and was confirmed by DSA in 1 case, making Klippel-Trénaunay-Weber syndrome a more apt diagnosis. Associated ipsilateral duplicated renal artery was found in 1 case. We have concluded that medical imaging is the cornerstone in the diagnosis and assessment of severity and complications, follow-up and differentiation of KTS from other similar conditions. Different imaging modalities play complementary roles in the evaluation of KTS patients.

Abstract 061: Mitochondrial Fission Mediates Hypertensive Vascular Remodeling and Aneurysm Development

The prevalence of hypertension is growing steadily with mortality reaching 30,221. While effective blood pressure reduction therapy exists, the underlying pathophysiology leading to vascular remodeling remains poorly understood. Hypertension is a risk factor for abdominal aortic aneurysms (AAA) which when ruptured has 80% mortality. Surgery is the only treatment due to insufficient understanding of the disease process. Mitochondrial dysfunction has been implicated in various cardiovascular diseases but the role of mitochondrial dynamics, a mechanism regulating mitochondrial homeostasis, is under-investigated in hypertension and aneurysm. Our data shows that enhancement of mitochondrial fission via a GTPase, Drp1, in vascular smooth muscle cells (VSMCs) is involved in hypertensive vascular remodeling and aneurysm. In vitro, AngII induced transient mitochondrial fission (2-4 h) and enhanced mitochondrial ROS production in rat aortic VSMCs. Mitochondrial fission, mito-ROS generation, total cell protein, cell volume and extracellular collagen increased by 100 nM AngII were all attenuated in VSMCs by pretreatment with adenovirus encoding Drp1 siRNA/control non-silencing RNA or mdivi1, a Drp1 inhibitor. In vivo, male C57BL/6 mice were infused with AngII (1000ng/kg/min) for 2 weeks (hypertensive remodeling model) +/- mdivi1 (25 mg/kg ip every other day) or infused with AngII for 4 weeks with beta-aminopropionitrile in the drinking water (AAA model) +/- mdivi1 (25 mg/kg ip 3x per week). In the 2-week AngII model, mdivi1 suppressed left ventricular hypertrophy, vascular hypertrophy and perivascular fibrosis induced by AngII in aorta, heart and kidney, independent of blood pressure. In the AAA model, mdivi1 attenuated aneurysm development (External AA diameter (mm) Mean±SEM: 2.15±0.13 vs 1.49±0.07 (, p<0.01). Reduced KDEL and nitro-tyrosine staining in aorta (4w model), coronary and renal arteries (2w) in mdivi1 treated mice, suggests attenuation of ER stress and oxidative stress, respectively. These data suggest that inhibition of mitochondrial fission prevents AngII-induced cardiovascular remodeling and aneurysm development independently of hypertension via ER stress/mito-ROS mechanisms.

Abstract P144: Characterization of Vascular Endothelial and Smooth Muscle Exosomes and Their Role in Vascular SignalTransduction

Vascular homeostasis is predicated on the integral interaction between a myriad of cell types. Principle to homeostasis is the interaction between the endothelial cells (ECs) of the intima and the vascular smooth muscle cells (VSMCs) of the media. Disruption of the tightly controlled communication between these cell types can lead to development of pathophysiology. In the past decade, much study has been given to a novel means of intercellular communication in exosomes. Exosomes are nanovesicles derived from endosomal compartments capable of carrying functional proteins, small RNAs and lipids into extracellular space. Initially characterized in the field of immunology, little is known on exosomes within vascular biology. Therefore, we present an in vitro characterization of rat EC and VSMC exosomes and evidence of EC exosomes as initiators of signal transduction within VSMCs. Primary rat aortic EC and VSMC exosomes isolated in serum-free conditions displayed characteristic size, shape and protein content of exosomes as analyzed through nanoparticle tracking analysis, electron microscopy, and western blot. Interestingly, alpha smooth muscle actin was found to be cell-specific for VSMC exosomes. Proteomics identified differential expression between EC and VSMC exosomes suggesting altered cargo between the two populations. Incubation of EC exosomes with VSMC identified a dose- and time-dependent increase in the expression of vascular cell adhesion molecule 1 in VSMC with a maximum at 10 9 EC exosomes and 6 hours through immunoblot analysis. In addition, EC exosomes stimulated expression of early growth response protein 1 at 1-3 hours, suggesting activation of pro-inflammatory gene expression. EC exosomes stimulated a maximal rate of protein synthesis at 3 hours in VSMC (3.53 fold increase over control, p=0.016) determined through puromycin incorporation showing qualitative changes in cell function. Analysis of cell volume identified a hypertrophic response in VSMC after exosome incubation as well, displaying a role for exosomes in vascular hypertrophy. In conclusion, we present a broad characterization of exosomes in vascular biology and a functional crosstalk mechanism between RAEC and VSMC through exosome transfer.

Abstract 060: Mitochondrial Deacetylase Sirt3 in Endothelial and Smooth Muscle Cells Protects From Vascular Dysfunction and Attenuates Hypertension

Vascular dysfunction plays a key role in the development of hypertension and heart disease which causes one-third of deaths worldwide. Cardiovascular disease risk factors reduce mitochondrial deacetylase Sirt3 and Sirt3 declines with age paralleling the increased incidence of cardiovascular disease and hypertension; however, the role of Sirt3 was largely ignored. We hypothesized that Sirt3 plays critical role in vascular dysfunction and hypertension. To test this hypothesis we have developed novel tamoxifen-inducible endothelium specific Sirt3 knockout (Ec Sirt3KO ), endothelial Sirt3 overexpressing (Ec Sirt3OX ), smooth muscle Sirt3 knockout (Smc Sirt3KO ), smooth muscle Sirt3 overexpressing (Smc Sirt3OX ) and global Sirt3 overexpressing (Sirt3OX) mice on C57Bl/6J background, and examined the effect of Sirt3 expression on vascular dysfunction and angiotensin II-induced hypertension. It was found that cell-specific Sirt3 depletion in endothelial and smooth muscle in Ec Sirt3KO and Smc Sirt3KO mice increases vascular permeability by 2-fold, raises T cell and monocyte vascular accumulation, diminishes endothelial NO and increases blood pressure by 10 mm Hg compared with wild-type Sham mice. Angiotensin II infusion in Ec Sirt3KO and Smc Sirt3KO mice caused vascular hyperpermeability, increased vascular hypertrophy, exacerbated endothelial dysfunction and hypertension. Meanwhile, Sirt3 overexpression reduced vascular permeability and diminished vascular inflammation compared to Sham wild-type mice. Sirt3 overexpression in endothelial and smooth muscle prevents angiotensin II-induced vascular hyperpermeability, inhibits vascular oxidative stress, preserves endothelial-dependent relaxation, diminishes vascular hypertrophy and attenuates hypertension by 20 mm Hg in angiotensin II-infused Ec Sirt3OX and Smc Sirt3OX mice compared with the wild-type littermates. Interestingly, Sirt3 depletion in human aortic endothelial cells and human vascular smooth muscle cells reduces expression of differentiation markers. We suggest that Sirt3 is central in redox and metabolic regulations of smooth muscle and endothelial cells. Our data support a therapeutic potential of targeting Sirt3 in vascular dysfunction and hypertension.

Lead Poisoning in Cattle Held in a Military Training area

Background: Lead poisoning is one of the major toxic diseases of cattle. Contamination occurs with ingestion of products containing lead, especially batteries, or through contaminated pastures and water sources. Clinical signs are neurological and necropsy findings and histopathological changes may vary depending on the clinical presentation. Although the diseaseis widely reported in the literature, there are rare descriptions of intoxication in cattle raised in military training areas. This work describes the epidemiological, clinical and anatomopathological features of an outbreak of lead poisoning in cattle kept in a military artillery training camp.Case: Fifteen cattle out of a herd of sixty 4-6 year-old, mixed breed castrated males were affected. The cattle were held in a 100 ha of native pasture used for military artillery training. After three weeks in this area, the affected cattle had predominantly neurological clinical manifestations, characterized by somnolence, ambulatory incoordination, muscle tremors,bruxism, aimless walking, blindness and decubitus. The clinical course was 24-72 h. Eight of the 15 affected cattle died and two were necropsied. Necropsy finds were non-specific and the histological lesions of both necropsied cattle were restricted to the brain and kidneys. Laminar neuronal necrosis, neuropil vacuolization (spongiosis) and vascular endothelial hypertrophy were observed in the telencephalic cortex. Additionally there was astrocytic degeneration and neuronophagia.There was degeneration and necrosis of renal tubular epithelium and in one bovine there were intranuclear inclusion bodies in the renal epithelial cells; these inclusion bodies were highlighted using both modified Ziehl-Neelsen and periodic acid Schiff (PAS) stains. The levels of lead found in the kidneys and livers of the two necropsied cattle were respectively51.7 μg/g and 41.00 μg/g for one of the necropsied cattle; and 431μg/g and 39.0 μg/g for the other. After the diagnosis of intoxication, cattle were removed from the area and the remaining seven affected bovines recovered.Discussion: The diagnosis of lead poisoning in cattle in the current study was based on epidemiological, clinical, anatomopathological data and in the determination of lead levels in the kidney and liver. The association of these data provides an invaluable aid in confirming a presumptive diagnosis of lead poisoning. Pasturing on military artillery training fieldsis a rarely described form source of lead for the intoxication in bovine species. In such cases, cattle may ingest the lead directly from the soil or through contaminated pastures containing lead dust on the surface of the leaves. Histologically, laminar neuronal necrosis in the telencephalic cortex, associated with tubular necrosis and intranuclear inclusion bodies intubular epithelial cells, are characteristic features of the intoxication. These changes are usually associated with ischemic anoxia in the nervous system and alteration in nuclear function which interferes in gene expression in the kidney. Lead poisoning in cattle should be differentiated from other neurological conditions, especially rabies, hepatic encephalopathyand several causes of polioencephalomalacia. Areas of military artillery training are unfit for the development of agricultural exploitation activities, as they represent potential sources of contamination for livestock.Keywords: diseases of cattle, toxicology, heavy metal, polioencephalomalacia.

Genomics of Fibromuscular Dysplasia.

Fibromuscular Dysplasia (FMD) is “an idiopathic, segmental, non-atherosclerotic and non-inflammatory disease of the musculature of arterial walls, leading to stenosis of small and medium-sized arteries” (Persu, et al; 2014). FMD can lead to hypertension, arterial dissections, subarachnoid haemorrhage, stroke or mesenteric ischemia. The pathophysiology of the disease remains elusive. While familial cases are rare (<5%) in contemporary FMD registries, there is evidence in favour of the existence of multiple genetic factors involved in this vascular disease. Recent collaborative efforts allowed the identification of a first genetic locus associated with FMD. This intronic variant located in the phosphatase and actin regulator 1 gene (PHACTR1) may influence the transcription activity of the endothelin-1 gene (EDN1) located nearby on chromosome 6. Interestingly, the PHACTR1 locus has also been involved in vascular hypertrophy in normal subjects, carotid dissection, migraine and coronary artery disease. National and international registries of FMD patients, with deep and harmonised phenotypic and genetic characterisation, are expected to be instrumental to improve our understanding of the genetic basis and pathophysiology of this intriguing vascular disease.

Abstract 098: Next Generation MicroRNA Sequencing to Identify Coronary Artery Disease Patients at Risk of Recurrent Myocardial Infarction

Background: Circulating miRNA have the potential to become reliable biomarkers for risk stratification and early detection of cardiovascular events. Methods: In a single center cohort study, whole blood was collected from 437 subjects undergoing cardiac catheterization, who were followed for recurrent cardiovascular events during a mean follow up of 1.5 years. We selected a case cohort (n=22) with recurrent thrombotic events on standard medical therapy (stent thrombosis (n=6) or spontaneous myocardial infarction (MI) (n=16)) and a matched cohort with CAD, but uneventful clinical follow up (n=26), as well as a control group with cardiovascular risk factors, but without angiographic CAD (n=24). We performed complete miRNA next generation sequencing of RNA extracted from whole blood samples (including leukocytes and platelets). Results: Differential pattern of miRNA expression was demonstrated between controls, CAD patients with no events, and CAD patients with recurrent events (figure). MiRNA that have been previously associated with MI, CAD, endothelial function, vascular smooth muscle cells, platelets, angiogenesis, heart failure, cardiac hypertrophy, arrhythmia, and stroke were replicated in our CAD case-control cohorts. Twenty miRNA (FDR&lt;0.05) were linked with risk of recurrent myocardial infarction and stent thrombosis, as compared to CAD patients with uneventful follow up. Conclusions: MiRNA next generation sequencing demonstrates altered fingerprint profile of whole blood miRNA expression among subjects with subsequent recurrent coronary thrombotic events on standard medical therapy (‘non-responders’), as compared to subjects with no recurrent cardiovascular events. MiRNA profiling may identify high risk subjects and provide additional insights into disease mechanisms not currently attenuated with standard medical therapy used in treatment of CAD.

IGF‐1 deficiency promotes pathological remodeling of cerebral arteries: a potential mechanism contributing to the pathogenesis of intracerebral hemorrhages in aging

Clinical and experimental studies show that age‐related decline in circulating IGF‐1 levels promotes the pathogenesis of intracerebral hemorrhages, which critically contribute to the development of vascular cognitive impairment and disability in older adults. Yet, the mechanisms by which IGF‐1 deficiency compromises structural integrity of the cerebral vasculature are not completely understood. To determine the role of IGF‐1 deficiency in pathological remodeling of middle cerebral arteries (MCAs), we compared alterations in vascular mechanics, morphology and remodeling‐related gene expression profile in mice with liver‐specific knockdown of IGF‐1 (Igf1f/f + TBG‐Cre‐AAV8) and control mice with or without hypertension induced by angiotensin‐II treatment. We found that IGF‐1 deficiency resulted in thinning of the media and decreased wall‐to‐lumen ratio in MCAs. MCAs of control mice exhibited structural adaptation to hypertension, manifested as a significant increase in wall thickness, vascular smooth muscle cell hypertrophy, decreased internal diameter and up‐regulation of extracellular matrix (ECM)‐related genes. IGF‐1 deficiency impaired hypertension‐induced adaptive media hypertrophy and dysregulated extracellular matrix remodeling, decreasing elastin content and attenuating adaptive changes in ECM‐related gene expression. Thus, circulating IGF‐1 plays a critical role in maintenance of the structural integrity of cerebral arteries. Alterations of VSMC phenotype and pathological remodeling of the arterial wall associated with age‐related IGF‐1 deficiency have important translational relevance for the pathogenesis of ICHs and vascular cognitive impairment in elderly hypertensive patients.Support or Funding InformationThis work was supported by grants from the American Heart Association, the National Center for Complementary and Alternative Medicine, and the National Institute on AgingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Understanding Angiotensin II Type 1 Receptor Signaling in Vascular Pathophysiology.

Angiotensin II is the most important endocrine ligand in the renin–angiotensin system (RAS), contributing to the development of several cardiovascular diseases including hypertension.1 Angiotensin II mediates its signal transduction and functions via the angiotensin II receptors.2 Historically, the presence of 2 subtypes of angiotensin II receptors were pharmacologically recognized based on the sensitivity to the first orally active nonpeptide angiotensin II receptor antagonist, losartan. The losartan-sensitive receptor was termed AT1 (angiotensin II receptor type 1) receptor. It was assumed to be a heterotrimeric GPCR (G protein–coupled receptor) because it generates inositol triphosphate and diacylglycerol, leading to intracellular Ca2+ elevation and protein kinase C activation, respectively. Most known physiological and pathophysiological functions of angiotensin II, including stimulation of vasoconstriction and salt and water reabsorption, are mediated through the AT1 receptor. The losartan-insensitive receptor was termed AT2 receptor, whereas its G protein coupling remains unclear.1,3,4 In 1991, 2 research groups in the United States independently isolated cDNA (termed AGTR1) encoding the mammalian AT1 receptor.5,6 Subsequently, rat AT2 receptor cDNA (AGTR2) was cloned in 1993.7,8 This pioneer work revealed complete amino acid sequences of the angiotensin II receptor subtypes belonging to the 7-transmembrane GPCR superfamily. In the early 1990s, several studies reported that AT1 receptor elicits tyrosine phosphorylation of multiple proteins and activation of MAPK (mitogen-activated protein kinase; eg, p42/p44 MAPK)/ERK (extracellular signal–regulated kinase; eg, ERK1/2) in various cell types including vascular smooth muscle cells (VSMC). The early 1990s also saw the establishment of the concept that angiotensin II via the AT1 receptor has a direct action on cardiac myocytes, fibroblasts, and VSMCs causing hypertrophic and fibrotic cardiovascular remodeling.9,10 The cardiovascular remodeling caused by angiotensin II seemed to be …

Quantification of alignment of vascular smooth muscle cells.

Vascular smooth muscle cells (VSMCs) are essential components that keep the tonus of the arterial network, which is the channel used to conduct the blood from the heart to the peripheral areas of the body. It is known that mechanical and architectural changes in VSMCs may lead to functional modifications in the cardiovascular system; therefore, the quantitative characterization of these changes can help to elucidate questions that remain unclear in pathological situations, such as hypertension, vasospasm, vascular hypertrophy, and atherosclerosis. In this work, we have developed a new framework of image processing using the Sobel operator, associated with statistical analysis, to determine the degree of local alignment of actin filaments, which we found to be directly related with the distensibility of the arterial wall. We have also compared these results with the rigidity of the cytoskeleton of VSMCs. The results suggest that the alignment degree increases from peripheral arteries, such as carotid and femoral, to central arteries, as well coronary and thoracic aorta, which can indicate that the level of local alignment of the actin fibers in VSMCs is related with the mechanical behavior of the arterial wall. © 2018 International Society for Advancement of Cytometry.

Correlation among lipid parameters, pulse wave velocity and central blood pressure in young Korean population

ABSTRACTBackground: Central blood pressure is closely related to the important cardiovascular intermediate end points, such as vascular hypertrophy and extent of carotid atherosclerosis. Therefore it is prudent to study correlation among central aortic blood pressure, body composition, lipid profiles, and pulse wave velocity in population-based study. Consequently, we investigate the correlation between central aortic blood pressure and other risk parameters of hypertension such as body composition and lipid profile. Methods: We recruited 20 young participants diagnosed with hypertension as well as 30 without hypertension. The study used an X-SCAN PLUS 950 machine for measurement of overall body composition. Measurements of central blood pressure and carotid–femoral pulse wave velocity were carried out using SphygmoCor XCEL. Results: The hypertensive participants had significantly higher total weight without fat, body moisture mass, muscle mass, body mass index, basal metabolic rate, intracellular and extracellular water contents, protein and mineral contents along with brachial and central aortic blood pressures. In both hypertensive and non-hypertensive participants, central aortic diastolic blood pressure were significantly related to the lipid parameters. Conclusion: Overall, the correlations between central blood pressure, pulse wave velocity, and lipid profile in hypertensive and non-hypertensive participants were substantial.

Hyperleptinemia positively associated with central arterial stiffness in hemodialysis patients

ObjectiveLeptin plays a role in stimulating vascular inflammation, vascular smooth muscle hypertrophy, and augmenting blood pressure, which contributes to the pathogenesis of atherosclerosis and leads to arterial stiffness. This vascular damage, measured by carotid-femoral pulse wave velocity (cfPWV), is recognized as an independent predictor of cardiovascular mortality in hemodialysis (HD) patients. The aim of this study was to evaluate the relationship between serum leptin and arterial stiffness in HD patients.Patients and methodsIn 112 of the 126 HD patients were eligible and their biochemical data were collected for analysis. Serum leptin level was measured using a commercial enzyme-linked immunosorbent assay kit. Carotid-femoral pulse wave velocity was measured by a validated tonometry system (SphygmoCor). Those have cfPWV values above 10 m/s are defined as the high arterial stiffness group.ResultsAmong the participants, thirty-eight of them who were in the high arterial stiffness group, had a higher prevalence of diabetes mellitus (p = 0.002), age (p = 0.029), body mass index (BMI, p = 0.018), body fat mass (p = 0.001), hemoglobin (p = 0.040), and serum leptin levels (P<0.001). Multivariable logistic regression analysis showed that leptin (odds ratio [OR] 1.09; 95% confidence interval [CI] 1.04–1.14; p <0.001), diabetes (OR 7.17; CI 1.39–37.00; p = 0.019), body fat mass (OR 1.16; CI 1.02–1.33; p = 0.027); and hemoglobin (OR 2.11; CI 1.15–3.87; p = 0.015) were independently associated with arterial stiffness in HD patients.ConclusionIn our study, hyperleptinemia was positively correlated to the high cfPWV and thus was related to high arterial stiffness in HD patients.