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Vascular physiology

Pan Dan, Émilie Velot, Grégory Francius, Patrick Menu, Véronique Decot
: One of the outstanding goals in tissue engineering is to develop a natural coating surface which is easy to manipulate, effective for cell adhesion and fully biocompatible. The ideal surface would be derived from human tissue, perfectly controllable, and pathogen-free, thereby satisfying all of the standards of the health authorities. This paper reports an innovative approach to coating surfaces using a natural extracellular matrix (ECM) extracted from the Wharton's jelly (WJ) of the umbilical cord (referred to as WJ-ECM)...
October 18, 2016: Acta Biomaterialia
Anders J Davidson, Lucas P Neff, Joseph J DuBose, James B Sampson, Christopher M Abbot, Timothy K Williams
Peripheral vascular injuries carry significant risk for permanent functional impairment, limb loss, and death. Definitive correction of these injuries requires significant operative time and has traditionally been resource and skill set intensive. In the initial surgical treatment of the physiologically depleted trauma patient, faster techniques may prove more appropriate. Damage control techniques, including vascular shunting, rapidly restore distal flow but require additional vascular intervention and risk shunt thrombosis with prolonged use...
November 2016: Journal of Trauma and Acute Care Surgery
Riccardo Toninato, Silvia Scuri, Vincenzo Tarzia, Gino Gerosa, Francesca M Susin
PURPOSE: The gold standard therapy for patients with advanced heart failure is heart transplant. The gap between donors and patients in waiting lists promoted the development of circulatory support devices, such as the total artificial heart (TAH). Focusing on in vitro tests performed with CardioWest™ TAH (CW) driven by the SynCardia Freedom® portable driver (FD) the present study goals are: i) prove the reliability of a hydraulic circuit used as patient simulator to replicate a quasi-physiological scenario for various hydrodynamic conditions, ii) investigate the hydrodynamic performance of the CW FD, iii) help clinicians in possible interpretation of clinical cases outcomes...
October 15, 2016: International Journal of Artificial Organs
Carolina Rodriguez-Tirado, Takanori Kitamura, Yu Kato, Jeffery W Pollard, John S Condeelis, David Entenberg
Metastasis to secondary sites such as the lung, liver and bone is a traumatic event with a mortality rate of approximately 90% (1). Of these sites, the lung is the most difficult to assess using intravital optical imaging due to its enclosed position within the body, delicate nature and vital role in sustaining proper physiology. While clinical modalities (positron emission tomography (PET), magnetic resonance imaging (MRI) and computed tomography (CT)) are capable of providing noninvasive images of this tissue, they lack the resolution necessary to visualize the earliest seeding events, with a single pixel consisting of nearly a thousand cells...
October 6, 2016: Journal of Visualized Experiments: JoVE
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Carlota Saldanha
Nitric oxide (NO) produced by endothelial cells interacts with erythrocyte through band 3 protein, being scavenged by haemoglobin. A signal transduction mechanism involving protein Gi and protein band 3 stimulates erythrocyte NO efflux when acetylcholine (ACh) binds to erythrocyte membrane acetylcholinesterase. Binding of normal plasma fibrinogen (Fib) levels, to erythrocyte membrane CD47 decreases the NO efflux. When high Fib concentration and ACh were present the efflux of NO from erythrocytes was normalized...
October 20, 2016: Clinical Hemorheology and Microcirculation
Brun Jean-Frédéric, Boulot Pierre, Varlet-Marie Emmanuelle
Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical 'ideal' hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η) ratio vs hct constructed with Quemada's model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied...
October 18, 2016: Clinical Hemorheology and Microcirculation
Matthias Jacob, Daniel Chappell, Bernhard F Becker
Oxygen delivery to cells is the basic prerequisite of life. Within the human body, an ingenious oxygen delivery system, comprising steps of convection and diffusion from the upper airways via the lungs and the cardiovascular system to the microvascular area, bridges the gap between oxygen in the outside airspace and the interstitial space around the cells. However, the complexity of this evolutionary development makes us prone to pathophysiological problems. While those problems related to respiration and macrohemodynamics have already been successfully addressed by modern medicine, the pathophysiology of the microcirculation is still often a closed book in daily practice...
October 21, 2016: Critical Care: the Official Journal of the Critical Care Forum
Yang Li, Jian Li, Zhiwen Hou, Yang Yu, Bo Yu
The primary physiological function of Krüppel-like zinc-finger transcription factor (KLF5) is the regulation of cardiovascular remodeling. Vascular remodeling is closely related to the amelioration of various ischemic diseases. However, the underlying correlation of KLF5 and ischemia is not clear. In this study, we aim to investigate the role of KLF5 in myocardial ischemia reperfusion (IR) injury and the potential mechanisms involved. Cultured H9C2 cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/Rep) to mimic myocardial IR injury in vivo...
October 17, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Ning Xia, Huige Li
Under physiological conditions, perivascular adipose tissue (PVAT) attenuates agonist-induced vasoconstriction by releasing vasoactive molecules including hydrogen peroxide, angiotensin 1-7, adiponectin, methyl palmitate, hydrogen sulfide, nitric oxide (NO) and leptin. This anticontractile function of PVAT is lost under conditions of obesity. The central mechanism underlying PVAT dysfunction in obesity is likely to be an "obesity triad" (consisting of PVAT hypoxia, inflammation and oxidative stress) that leads to dysregulation of PVAT-derived vasoregulators...
October 20, 2016: British Journal of Pharmacology
Jamal El-Saghir, Farah Nassar, Nadim Tawil, Marwan El-Sabban
BACKGROUND: Exosomes are membrane nano-vesicles secreted by a multitude of cells that harbor biological constituents such as proteins, lipids, mRNA and microRNA. Exosomes can potentially transfer their cargo to other cells, implicating them in many patho-physiological processes. Mesenchymal stem cells (MSCs), residents of the bone marrow and metastatic niches, potentially interact with cancer cells and/or their derived exosomes. In this study, we investigated whether exosomes derived from adult T-cell leukemia/lymphoma (ATL) cells act as intercellular messengers delivering leukemia-related genes that modulate the properties of human MSCs in favor of leukemia...
October 19, 2016: Retrovirology
Welma Stonehouse, Grant D Brinkworth, Campbell H Thompson, Mahinda Y Abeywardena
BACKGROUND AND AIMS: In vitro, ex vivo and animal studies suggest palm-based tocotrienols and carotenes enhance vascular function, but limited data in humans exists. The aim was to examine the effects of palm-tocotrienols (TRF- 80) and palm-carotene (CC-60) supplementation on vascular function and cardiovascular disease (CVD) risk factors in adults at increased risk of impaired vascular function. METHODS: Ninety men and women (18-70 yr, 20-45 kg/m(2)) with type 2 diabetes, impaired fasting glucose and/or elevated waist circumference were randomised to consume either TRF-80 (420 mg/day tocotrienol + 132 mg/day tocopherol), CC-60 (21 mg/day carotenes) or placebo (palm olein) supplements for 8 weeks...
October 14, 2016: Atherosclerosis
Michel van Schaardenburgh, Martin Wohlwend, Øivind Rognmo, Erney J R Mattsson
PURPOSE: Mitochondria are essential for energy production in the muscle cell and for this they are dependent upon a sufficient supply of oxygen by the circulation. Exercise training has shown to be a potent stimulus for physiological adaptations and mitochondria play a central role. Whether changes in mitochondrial respiration are seen after exercise in patients with a reduced circulation is unknown. The aim of the study was to evaluate the time course and whether one session of calf raise exercise stimulates mitochondrial respiration in the calf muscle of patients with peripheral vascular disease...
2016: PloS One
Malgorzata Furmanik, Catherine M Shanahan
Cardiovascular disease continues to be the leading cause of death in industrialised societies. The idea that the arterial smooth muscle cell (ASMC) plays a key role in regulating many vascular pathologies has been gaining importance, as has the realisation that not enough is known about the pathological cellular mechanisms regulating ASMC function in vascular remodelling. In the past decade endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been recognised as a stress response underlying many physiological and pathological processes in various vascular cell types...
October 13, 2016: Current Cardiology Reviews
Zhanna Kobalava
The burden of cardiovascular diseases (CVD) in general and heart failure (HF) in particular continues to increase worldwide. CVD are major contributors to death and morbidity and recognized as important drivers of healthcare expenditure. Chronic overactivity of the renin-angiotensin-aldosterone system (RAAS) plays a key role in human hypertension and HF pathophysiology. RAAS is fundamental in the overall regulation of cardiovascular homeostasis through the actions of hormones, which regulate vascular tone, and specifically blood pressure through vasoconstriction and renal sodium and water retention...
September 2016: Journal of Hypertension
Ben Clark, Sarah Withers, Anthony Heagerty
OBJECTIVE: Resistance arteries significantly contribute to peripheral vascular resistance, and also determine insulin-sensitivity by controlling blood flow to skeletal muscle. Increased microvascular tone therefore facilitates the development of hypertension and insulin-resistance. Surrounding most blood vessels, perivascular adipose tissue (PVAT) exerts a vasorelaxant 'anti-contractile' effect. Few studies on skeletal muscle resistance arteries have investigated this vasorelaxant effect and the role of insulin...
September 2016: Journal of Hypertension
Karima Ait-Aissa, Joseph Hockenberry, David Gutterman, Aron Geurts, Andreas Beyer
OBJECTIVE: Flow mediated dilation (FMD) is the most physiological relevant form of endothelial-mediated vasodilation. Our laboratory has previously shown that telomerase, a ribo-nucleoprotein that counteracts telomere shortening, has a protective effect on endothelial function under conditions of oxidative stress in the human microcirculation. In the presence of coronary artery disease, decreased telomerase activity contributes to a shift in the mediator of FMD from atheroprotective nitric oxide (NO) to pro-inflammatory and atherogenic hydrogen peroxide (H2O2)...
September 2016: Journal of Hypertension
Stephen Harrap
Genetic discovery in blood pressure is generally referenced in relation to protein-coding genes, despite the fact that genes less than 2% of the genome. Recent exploration of the DNA sequences between genes, once called "junk" DNA, has revealed a wealth of transcripts for RNA species that do not encode protein. These non-coding RNAs (ncRNAs) have emerged as dynamic managers of the business of the genome, able to coordinate the expression of genes in time and space to achieve the complexities of normal development and growth...
September 2016: Journal of Hypertension
Alexander Reinthaller
Angiogenesis plays a pivotal role in normal ovarian physiology as well as in the formation and progression of ovarian cancer. Several well-designed phase II and III trials studied the efficacy of antiangiogenic agents in advanced ovarian cancer. The results of these trials demonstrated significantly prolonged progression-free survival when antiangiogenic agents were used as a maintenance therapy. To date, no effect on overall survival could be ascertained. The most widely studied antiangiogenic agent, bevacizumab - a monoclonal humanized antibody against vascular endothelial growth factor - was effective in all phases of the disease (first-line therapy, platinum-sensitive and platinum-resistant recurrence)...
2016: Memo
Anikó Ilona Nagy, Ashwin Venkateshvaran, Béla Merkely, Lars H Lund, Aristomenis Manouras
AIMS: The diastolic pulmonary pressure gradient (DPG) has recently been introduced as a specific marker of combined pre-capillary pulmonary hypertension (Cpc-PH) in left heart disease (LHD). However, its diagnostic and prognostic superiority compared with traditional haemodynamic indices has been challenged lately. Current recommendations explicitly denote that in the normal heart, DPG values are greater than zero, with DPG ≥7 mmHg indicating Cpc-PH. However, clinicians are perplexed by the frequent observation of DPG <0 mmHg (DPGNEG ), as its physiological explanation and clinical impact are unclear to date...
October 17, 2016: European Journal of Heart Failure
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