Intravenous Administration of Allogenic Cell-Derived Microvesicles of Healthy Origins Defend Against Atherosclerotic Cardiovascular Disease Development by a Direct Action on Endothelial Progenitor Cells.

Atherosclerosis and cardiovascular disease development is the outcome of intermediate processes where endothelial dysfunction and vascular inflammation are main protagonists. Cell-derived microvesicles (MVs), endothelial progenitor cells (EPCs), and circulating microRNAs (miRNAs) are known as biomarkers and potential regulators for atherosclerotic vascular disease, but their role in the complexity of the inflammatory process and in the mechanism of vascular restoration is far from clear. We aimed to evaluate the biological activity and functional role of MVs, in particular of the EPCs-derived MVs (MVEs), of healthy origins in reducing atherosclerotic vascular disease development. The experiments were performed on hamsters divided into the following groups: simultaneously hypertensive-hyperlipidemic (HH group) by combining two feeding conditions for 4 months; HH with retro-orbital sinus injection containing 1 × 105 MVs or MVEs from control hamsters, one dose per month for 4 months of HH diet, to prevent atherosclerosis (HH-MVs or HH-MVEs group); and controls (C group), age-matched normal healthy animals. We found that circulating MV and MVE transplantation of healthy origins significantly reduces atherosclerosis development via (1) the mitigation of dyslipidemia, hypertension, and circulating EPC/cytokine/chemokine levels and (2) the structural and functional remodeling of arterial and left ventricular walls. We also demonstrated that (1) circulating MVs contain miRNAs; this was demonstrated by validating MVs and MVEs as transporters of Ago2-miRNA, Stau1-miRNA, and Stau2-miRNA complexes and (2) MV and MVE administration significantly protect against atherosclerotic cardiovascular disease via transfer of miR-223, miR-21, miR-126, and miR-146a to circulating late EPCs. It should be mentioned that the favorable effects of MVEs were greater than those of MVs. Our findings suggest that allogenic MV and MVE administration of healthy origins could counteract HH diet-induced detrimental effects by biologically active miR-10a, miR-21, miR-126, and miR-146a transfer to circulating EPCs, mediating their vascular repair function in atherosclerosis processes.

Endothelium structure and function in kidney health and disease.

The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.

Cellular resolution corneal imaging with extended imaging range.

Current optical coherence tomography (OCT) technology, which is used for imaging the eye's anterior segment, has been established as a clinical gold standard for the diagnosis of corneal diseases. However, the cellular resolution level information that is critical for many clinical applications is still not available. The major technical challenges toward cellular resolution OCT imaging are the limited ranging depth and depth of focus (DOF). In this work, we present a novel ultrahigh resolution OCT system that achieves an isotropic spatial resolution of <2 µm in tissue. The proposed system could approximately double the ranging depth and extend the DOF using the dual-spectrometer design and the forward-model based digital refocusing method, respectively. We demonstrate that the novel system is capable of visualizing the full thickness of the pig cornea over the ranging depth of 3.5 mm and the border of the corneal endothelial cells 8 times Rayleigh range away from the focal plane. This technology has the potential to realize cellular resolution corneal imaging in vivo.

Histological verification of atherosclerosis due to bends and bifurcations in carotid arteries predicted by hemodynamic model / Confirmação histológica de aterosclerose devido a dobras e bifurcações das artérias carótidas previstas por modelo hemodinâmico

Tortuosity and bifurcations in carotid arteries alter the blood flow, causing atherosclerosis. Objectives:The aim of the present study is to analyze the effect of variant vascular anatomy in the cervical region on development of atherosclerosis by microanatomical examination. Methods: The effect of blood flow at anomalous bends and bifurcations was observed in right carotid arteries of a seventy year old female cadaver. Fifteen histological slides were prepared from the carotid arteries and interpreted to verify predictions of atherosclerosis. Results: The model predicts atherosclerosis at bends, bifurcations and large aperture arteries. Microanatomical examination revealed presence of atherosclerosis of varying thickness at the bends and bifurcation in the right carotid arteries, as predicted. Atherosclerosis was also detected in the straight part of the wider common carotid artery. No atherosclerosis was observed in the contralateral carotid arteries. The variant carotid vascular anatomy consisting of bends, bifurcations and wider arteries revealed that the shear stress and velocity of blood flow are reduced at these anomalous sites. Conclusions: Anatomical anomalies such as bends and branching in the carotid arteries alter the irrigation pattern and generate biomechanical forces that cause turbulent flow and reduce shear stress/blood flow velocity. Decreased shear stress and velocity causes development of atherosclerosis. Histological slides established the presence of atherosclerosis at bends and bifurcations and in wider arteries

Tortuosidade e bifurcações das artérias carótidas alteram o fluxo sanguíneo, causando aterosclerose. Objetivos: O objetivo do presente estudo foi analisar o efeito de anatomia vascular variante na região cervical sobre o desenvolvimento de aterosclerose via exame microanatômico. Métodos: O efeito do fluxo sanguíneo em dobras e bifurcações anômalas foi observado nas artérias carótidas do lado direito em um cadáver do sexo feminino de 70 anos de idade. Quinze lâminas histológicas foram preparadas a partir das artérias carótidas e interpretadas para confirmar as previsões de aterosclerose. Resultados: O modelo prevê aterosclerose em dobras, bifurcações e artérias de grande calibre. O exame microanatômico revelou a presença de aterosclerose de densidades variáveis nas dobras e bifurcação das artérias carótidas do lado direito, conforme previsto. Aterosclerose também foi detectada na parte reta da artéria carótida comum mais larga. Não foi observada aterosclerose nas artérias carótidas contralaterais. A anatomia vascular carotídea variante consistindo de dobras, bifurcações e artérias mais largas revelou que a tensão de cisalhamento (shear stress) e a velocidade do fluxo sanguíneo são reduzidos nesses pontos anômalos. Conclusões: Anomalias anatômicas tais como dobras e ramificações das artérias carótidas alteram o padrão de irrigação e geram forças biomecânicas que causam fluxo turbulento e reduzem a tensão de cisalhamento e a velocidade do fluxo. Tensão e velocidade menores causam o desenvolvimento de aterosclerose. As lâminas histológicas estabeleceram a presença de aterosclerose nas dobras e bifurcações nas artérias mais largas

Discontinuities in the endothelium of epiphyseal cartilage canals and relevance to joint disease in foals.

Cartilage canals have been shown to contain discontinuous blood vessels that enable circulating bacteria to bind to cartilage matrix, leading to vascular occlusion and associated pathological changes in pigs and chickens. It is also inconsistently reported that cartilage canals are surrounded by a cellular or acellular wall that may influence whether bacterial binding can occur. It is not known whether equine cartilage canals contain discontinuous endothelium or are surrounded by a wall. This study aimed to examine whether there were discontinuities in the endothelium of cartilage canal vessels, and whether canals had a cellular or acellular wall, in the epiphyseal growth cartilage of foals. Epiphyseal growth cartilage from the proximal third of the medial trochlear ridge of the distal femur from six healthy foals that were 1, 24, 35, 47, 118 and 122 days old and of different breeds and sexes was examined by light microscopy (LM), transmission electron microscopy (TEM) and immunohistochemistry. The majority of patent cartilage canals contained blood vessels that were lined by a thin layer of continuous endothelium. Fenestrations were found in two locations in one venule in a patent cartilage canal located deep in the growth cartilage and close to the ossification front in the 118-day-old foal. Chondrifying cartilage canals in all TEM-examined foals contained degenerated endothelial cells that were detached from the basement membrane, resulting in gap formation. Thirty-three percent of all canals were surrounded by a hypercellular rim that was interpreted as contribution of chondrocytes to growth cartilage. On LM, 69% of all cartilage canals were surrounded by a ring of matrix that stained intensely eosinophilic and consisted of collagen fibres on TEM that were confirmed to be collagen type I by immunohistochemistry. In summary, two types of discontinuity were observed in the endothelium of equine epiphyseal cartilage canal vessels: fenestrations were observed in a patent cartilage canal in the 118-day-old foal; and gaps were observed in chondrifying cartilage canals in all TEM-examined foals. Canals were not surrounded by any cellular wall, but a large proportion was surrounded by an acellular wall consisting of collagen type I. Bacterial binding can therefore probably occur in horses by mechanisms that are similar to those previously demonstrated in pigs and chickens.

The allo-epi-endothelial lining of the intervillous space.

An unusual monolayer of cells lines the interface between the basal plate and the intervillous space in human term placenta but not the chorionic villi. Our recent descriptions of it are based on advanced microscopy, phenotyping and cytogenetic approaches. The papers show that the layer is partly epithelial (ectoderm) and partly endothelial (mesoderm): it is partly derived from the fetus and partly from the mother. This first accurate description of a naturally occurring human allo-epi-endothelium (monolayer of cells derived from two embryological germ layers and two individuals) is of interest in anatomy, obstetrics and gynaecology, developmental biology, histology and immunology. The most extensive evidence for this mosaic applies to the intervillous space lining layer of the basal plate where the endothelial proportion is of the order of 50%; it extends throughout central, intermediate and peripheral parts of the basal plate and is a consistent feature of the intervillous space lining of the chorionic plate also. Its presence lining chorionic plate is noteworthy as it includes the furthest parts of the sinus from the supplying and draining vessels which are endothelial lined.

Hemangioma sinusoidal. Estudio inmunohistoquímico con GLUT1 y WT1 / Sinusoidal Hemangioma: Immunohistochemical Analysis with Glucose Transporter 1(GLUT1) and Williams Tumor Protein 1(WT1)

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Hipercoagulabilidad y daño endotelial en pacientes con enfermedad pulmonar obstructiva crónica en fase estable / Hypercoagulability state and endotelial injury in stable chronic obstructive pulmonary disease patients

La enfermedad pulmonar obstructiva crónica es enla actualidad la cuarta causa de muerte en nuestro país.El principal agente causal de la enfermedad es el tabaco,cuyos efectos sobre el árbol bronquial no se limitanal parénquima pulmonar sino que además lesionan lapared endotelial, lo que podría contribuir a la apariciónde trombosis, isquemia o hipertensión pulmonar.En nuestro trabajo se estudia la existencia de unestado protrombótico en estos pacientes caracterizadopor la activación de la coagulación y por el daño endotelialy, para ello, se comparan las cifras de marcadoresbioquímicos en enfermos con EPOC y en sujetos sanos.Se seleccionaron 51 pacientes con EPOC y un grupode 30 voluntarios sanos de edades similares y secompararon las cifras de fibrinógeno, D-dímero, factorVIII y factor von Willebrand (FvW:Ag y FvW:Rico).Se observó un aumento de todos los marcadoresen el grupo de pacientes con respecto al grupo de controlessanos. Las diferencias encontradas fueron estadísticamentesignificativas en todos los casos (p<0,05).La EPOC se acompaña de un estado de activaciónde la coagulación y de un daño endotelial que podríancontribuir al desarrollo de complicaciones vascularescomo trombosis, isquemia o hipertensión pulmonar(AU)

COPD is currently the fourth cause of death in ourcountry; the main causal agent of the disease is tobaccowhose effects on the bronchial tree are not limited to thelung parenchyma. The action of tobacco injures the endothelialwall, which could contribute to lung thrombosis,ischemic events or secondary pulmonary hypertension.Our work investigates the existence of a prothomboticstate in these patients, characterized by the activationof clotting and endothelial injury, comparing thevalues of biochemical markers between COPD patientsand healthy volunteers.Fifty-one patients with COPD and a group of 30healthy volunteers of similar ages were selected and fibrinogen,D-dimer, factor VIII and von Willebrand factor(FvW:Ag and FvW:Rico) levels were compared.We found an increase of all markers in the patientgroup compared to the healthy control group. The differencesfound were statistically significant in all cases(p<0.05).COPD is characterized by a state of hypercoagulabilityand endothelial injury that they could contributeto the development of vascular complications such aslung thrombosis, ischemic events or secondary pulmonaryhypertension(AU)

Marcadores laboratoriais não tradicionais para aterosclerose: revisão de literatura / Non-traditional laboratory markets for atherosclerosis: review of the literature

As doenças cardiovasculares estão relacionadas com o processo aterosclerótico e o metabolismo lipídico. Apesar da importância dos lipídios sanguíneos na doença cardiovascular, 50 % dos infartos do miocárdio ocorrem em indivíduos sem hiperlipidemia. Nos últimos anos, estudos demonstram fatores de risco emergentes como marcadores de aterosclerose. Lipoproteína-A consiste essencialmente de uma partícula de LDL, limitada pela apoliproteína-a. Lipoproteína-A é associada à presença e extensão da doença coronariana. Proteína-C reativa desempenha um papel na terosclerose e complicações cardiovasculares. Evidências experimentais sugerem que a homocisteína pode estar envolvida na aterogênese e trombogênese. A importância da hiperfibrinogenemia como um fator de risco de aterotrombose...

Vascular protection by tetrahydrobiopterin: progress and therapeutic prospects.

Tetrahydrobiopterin (BH4) is an essential cofactor required for the activity of endothelial nitric oxide (NO) synthase. Suboptimal concentrations of BH4 in the endothelium reduce the biosynthesis of NO, thus contributing to the pathogenesis of vascular endothelial dysfunction. Supplementation with exogenous BH4 or therapeutic approaches that increase endogenous amounts of BH4 can reduce or reverse endothelial dysfunction by restoring production of NO. Improvements in formulations of BH4 for oral delivery have stimulated clinical trials that test the efficacy of BH4 in the treatment of systemic hypertension, peripheral arterial disease, coronary artery disease, pulmonary arterial hypertension, and sickle cell disease. This review discusses ongoing progress in the translation of knowledge, accumulated in preclinical studies, into the clinical application of BH4 in the treatment of vascular diseases. This review also addresses the emerging roles of BH4 in the regulation of endothelial function and their therapeutic implications.

A two-dimensional computational model of lymph transport across primary lymphatic valves.

This study utilizes a finite element model to characterize the transendothelial transport through overlapping endothelial cells in primary lymphatics during the uptake of interstitial fluid. The computational model is built upon the analytical model of these junctions created by Mendoza and Schmid-Schonbein (2003, "A Model for Mechanics of Primary Lymphatic Valves," J. Biomed. Eng., 125, pp. 407-414). The goal of the present study is to investigate how adding more sophisticated and physiologically representative biomechanics affects the model's prediction of fluid uptake. These changes include incorporating a porous domain to represent interstitial space, accounting for finite deformation of the deflecting endothelial cell, and utilizing an arbitrary Lagrangian-Eulerian algorithm to account for interacting and nonlinear mechanics of the junctions. First, the present model is compared with the analytical model in order to understand its effects on parameters such as cell deflection, pressure distribution, and velocity profile of the fluid entering the lumen. Without accounting for the porous nature of the interstitium, the computational model predicts greater cell deflection and consequently higher lymph velocities and flow rates than the analytical model. However, incorporating the porous domain attenuates the cell deflection and flow rate to values below that predicted by the analytical model for a given transmural pressure. Second, the present model incorporates recent experimental data for parameters such as lymph viscosity, transmural pressure measurements, and others to evaluate the ability of these junctions to act as unidirectional valves. The volume of flow through the valve is calculated to be 0.114 nL/microm per cycle for a transmural pressure varying between 8.0 mm Hg and -1.0 mm Hg at 0.4 Hz. Though experimental data for the absorption of lymph through these endothelial junctions are scarce, several measurements of lymph velocity and flow rates are cited to validate the present model.

Uma nova técnica para avaliar a lesão endotelial na arteriosclerose / A new technique to evaluate the endotelium lesion in atheroesclerosis

Os autores propõem uma nova técnica para avaliar a relação entre infecção e aterosclerose pela coleta de sangue da artéria coronária depois da lesão ou do seio coronariano em casos de insuficiência coronariana aguda durante a angioplastia, buscando bactérias, vírus e fragmentos de DNA virais

Prevenção primária da doença coronária pela atividade física / Coronary disease primary prevention and physical activity

A atividade física traz benefícios à saúde, reduz a morbidade e a mortalidade coronárias e restringe a atuação dos fatores de risco. O exercício mínino benéfico à saúde seria de 700kcal/semana, o que corresponderia a caminhar 10 km/semana. O exercício ideal, para a redução da doença coronária, seria de 2.000 kcal/semana, o que equivaleria a caminhar 39 km/semana(1 hora dia).Os efeitos do exercício são variados. As perdas de peso são discretas(2kg-3kg), e em associação a dieta trouxe reduções de 8,5 kg. Relatam-se pequenas diminuições do colesterol total (6,3 por cento)do LDL-colesterol(1 por cento-10 por cento), dos triglicérides(3 por cento-5 por cento)e da hemoglobina glicolisada A1c(0,5 por cento-1 por cento)e elevações do HDL-colesterol(3 por cento-5 por cento). Programas de dieta/caminhadas preveniram o diabetes do tipo II em população de risco(58 por cento, mudança de estilo de vida vs. 31 por cento, uso de metformina). Em hipertensos, registraram-se reduções de 7,4 mmHg-10mmHg na pressão sistólica e de 5,8 mmHg-7,5 mmHg na pressão diastólica. Exercícios intensos ativam a hemostasia, em altas concentrações, a adrenalina promove plaquetária. Em indivíduos treinados, verificou-se aumento da fibrinólise e redução da adesividade e agregabilidade plaquetárias. O exercício aumenta o shear stress, estimulando a formação de óxido nitrico no endotélio, inibindo a aterogênese e a inflamação. Os odds ratio para elevações de proteína C reativa variaram em indivíduos com atividade leve (0,53), moderada (0,85)e vigorosa(0,98).A adoção da atividade física implica incremento médio de expectativa de vida de 2,15 anos. Relatou-se redução da taxa de risco de óbito a 0,64-0,71 e a de infarto do miocárdio a 0,83 em indivíduos ativos. O grande desafio em um programa de exercício é a aderência. Algumas ecomendações são sugeridas para atenuar essa condição.

A molecular look at the glomerular barrier.

The glomerular barrier is the kidney's physical block to the unrestricted flow of molecules from the plasma into the urinary space. Its exquisite selectivity allows solutes and water in the glomerular capillaries to pass through, but it prevents the bulk of plasma proteins, most notably albumin, from crossing. Classically, the barrier consists of three distinct components: glomerular endothelium, glomerular basement membrane, and glomerular epithelium (podocytes). In this review, I discuss these three components, with particular emphasis on the barrier presumed to be imparted by a specialized podocyte cell-cell junction, the glomerular slit diaphragm.

Mechanotransduction and flow across the endothelial glycocalyx.

In this inaugural paper, we shall provide an overview of the endothelial surface layer or glycocalyx in several roles: as a transport barrier, as a porous hydrodynamic interface in the motion of red and white cells in microvessels, and as a mechanotransducer of fluid shearing stresses to the actin cortical cytoskeleton of the endothelial cell. These functions will be examined from a new perspective, the quasiperiodic ultrastructural model proposed in Squire et al. [Squire, J. M., Chew, M., Nneji, G., Neal, C., Barry, J. & Michel, C. (2001) J. Struct. Biol. 136, 239-255] for the 3D organization of the endothelial surface layer and its linkage to the submembranous scaffold. We shall show that the core proteins in the bush-like structures comprising the matrix have a flexural rigidity, EI, that is sufficiently stiff to serve as a molecular filter for plasma proteins and as an exquisitely designed transducer of fluid shearing stresses. However, EI is inadequate to prevent the buckling of these protein structures during the intermittent motion of red cells or the penetration of white cell microvilli. In these cellular interactions, the viscous draining resistance of the matrix is essential for preventing adhesive molecular interactions between proteins in the endothelial membrane and circulating cellular components.

Evidence for a second valve system in lymphatics: endothelial microvalves.

The mechanism for interstitial fluid uptake into the lymphatics remains speculative and unresolved. A system of intralymphatic valves exists that prevents reflow along the length of the lymphatic channels. However, these valves are not sufficient to provide unidirectional flow at the level of the initial lymphatics. We investigate here the hypothesis that initial lymphatics have a second, separate valve system that permits fluid to enter from the interstitium into the initial lymph channels but prevents escape back out into the tissue. The transport of fluorescent microspheres (0.31 microm) across endothelium of initial lymphatics in rat cremaster muscle was investigated with micropipette manipulation techniques. The results indicate that microspheres can readily pass from the interstitium across the endothelium into the lumen of the initial lymphatics. Once inside the lymphatic lumen, the microspheres cannot be forced out of the lumen even after elevation of the lymphatic pressure by outflow obstruction. Reaspiration of the microspheres inside the lymphatic lumen with a micropipette is blocked by the lymphatic endothelium. This blockade exists whether the aspiration is carried out at the microsphere entry site or anywhere along the initial lymphatics. Nevertheless, puncture of the initial lymphatic endothelium with the micropipette leads to rapid aspiration of intralymphatic microspheres. Investigation of lymphatic endothelial sections fixed during lymph pumping shows open interendothelial junctions not found in resting initial lymphatics. These results suggest that initial lymphatics have a (primary) valve system at the level of the endothelium. In conjunction with the classical (secondary) intralymphatic valves, the primary valves provide the mechanism that facilitates the unidirectional flow during periodic compression and expansion of initial lymphatics.

Liver sinusoidal endothelial cells are not permissive for adenovirus type 5.

Adenoviral vectors are known to transduce hepatocytes in normal liver tissue with high efficiency. The aim of this study was to investigate whether sinusoidal endothelial cells, which separate hepatocytes from the bloodstream in the sinusoidal lumen, are permissive for infection by adenoviruses. We show here that microvascular liver sinusoidal endothelial cells are not infected by adenovirus type 5 in vivo or in vitro unless high MOIs are used. In contrast, macrovascular endothelial cells from aorta are efficiently infected by adenovirus type 5. In addition, Kupffer cells, similar to sinusoidal endothelial cells, are not infected by adenovirus type 5. Liver sinusoidal endothelial cells do not express the integrin receptor alpha(v)beta3, which is required for efficient infection by adenoviruses. Our results demonstrate that hepatocytes are the main cell population of the liver that is infected by adenovirus type 5.