Acute and chronic venous thrombosis: Pathogenesis and new insights
Peter Gloviczki, Michael C. Dalsing, Bo Eklöf, Fedor Lurie, Thomas W. Wakefield, Monika L. Gloviczki in Handbook of Venous and Lymphatic Disorders, 2017
The endothelium forms the inner cell lining of all blood vessels in the body and is a spatially distributed organ. In an average individual, the endothelium weighs approximately 1 kg and covers a total surface area of 4000–7000 m2.15 The endothelium has been described as a primary determinant of pathophysiology or as a target for collateral damage in most, if not all, disease processes.15,16 Endothelial cells play a critical role in the balance between pro-coagulant and anticoagulant mechanisms in healthy individuals. The endothelium is integrally involved in mediating hemostasis.17 Despite this, the endothelial cells are considered mainly anti-thrombotic and pro-fibrinolytic; they are “mini-factories” for the production of many regulatory molecules that are pro-coagulants and anti-coagulants.17,18 In contrast, a pro-coagulant effect is observed during states of endothelial cell activation and disturbance, either physical (vascular trauma) or functional (sepsis).19 It is widely known that, under normal conditions, cellular blood components interact with the vessel wall, promoting vascular repair. Activated or dysfunctional endothelial cells trigger a mechanism of rapid deposition of platelets, erythrocytes, leukocytes, and insoluble fibrin, which establishes a thrombus.15
The circulatory system
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella in Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
The walls of the blood vessels may contain varying amounts of fibrous tissue, elastic tissue, and smooth muscle. All blood vessels are lined with a single layer of endothelial cells, as found forming the endothelium of the heart. The fibrous connective tissue provides structural support and stiffens the vessel. The elastic connective tissue allows vessels to expand and hold more blood. It also causes the vessels to recoil and exert pressure on the blood within the vessels, which pushes this blood forward. Most blood vessels contain smooth muscle that is arranged in either circular or spiral layers. Therefore, contraction of vascular smooth muscle, or vasoconstriction, narrows the diameter of the vessel and decreases the flow of blood through it. Relaxation of vascular smooth muscle, or vasodilation, widens the diameter of the vessel and increases the flow of blood through it. The smooth muscle of the vessel is innervated by the autonomic nervous system and is, therefore, physiologically regulated. Furthermore, this is where endogenous vasoactive substances and pharmacological agents exert their effects. The endothelium has several important physiological functions including contributing to the regulation of blood pressure, blood vessel growth and the exchange of materials between the blood and the interstitial fluid of the tissues (see Table 6.1).
Management and Prevention of Hypertension in the Elderly: A Yogic Approach
Anne George, Snigdha S. Babu, M. P. Ajithkumar, Sabu Thomas in Holistic Healthcare. Volume 2: Possibilities and Challenges, 2019
Endothelial dysfunction: Endothelial cell structure and functional integrity are important for various vital CV functions including homoeostatic regulation of BP.16 Vascular endothelium regulates several physiological properties of the blood vessel including vasodilatation, vascular permeability, and antithrombotic properties. One of the key molecules of endo-thelium that maintains vascular homoeostasis and integrity is nitric oxide (NO). Nitric oxide is a strong vasodilator. Sufficient bioavailability of NO is critical due to normal functioning of endothelium. With advancing age, bioavailability of NO is decreased resulting in endothelial dysfunction. Endothelial dysfunction is characterized by a shift of the normal endothelial function toward reduced vasodilator capacity, a proinflammatory state, and prothrombotic properties.17 Impaired NO-mediated vasodilatation is a potential contributor for stiffening of arteries and increasing peripheral vascular resistance, a pathognomonic characteristic of hypertension in the elderly.18,19 Vascular oxidative stress plays an important role in the mechanism of reduction of bioavailability of NO and endothelial dysfunction. Hence, age-associated increase in oxidative stress has been implicated as one of the underlying causes of hypertension.20–23
Endothelial function in patients with atrial fibrillation
Published in Annals of Medicine, 2020
Ahsan A. Khan, Graham N. Thomas, Gregory Y. H. Lip, Alena Shantsila
Endothelium refers to cells that line the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the vessel wall. It is a single layer of simple squamous cells lining the entire circulatory system, from the heart to the smallest capillaries [7]. Endothelium is mesodermal in origin. In a straight section of a blood vessel, vascular endothelial cells typically align and extend in the direction of fluid flow. Endothelial cells are able to alter their structure and phenotype depending on the vessel type. For example, endothelial cells lining the artery tend to be thicker than those in capillaries, which are fenestrated and thinner to allow for exchange of gases, nutrients and metabolites. Furthermore, endothelial cells can respond differently to stimulation in different vascular beds and even in different sections of the same vascular bed [8–10].
Targeted therapy of tumour microenvironment by gold nanoparticles as a new therapeutic approach
Published in Journal of Drug Targeting, 2022
Negah Mahhengam, Kimia Kazemnezhad, Hendrik Setia Budi, Mohammad Javed Ansari, Dmitry Olegovich Bokov, Wanich Suksatan, Lakshmi Thangavelu, Homayoon Siahmansouri
The vascular endothelium is a cohesive tissue that separates circulating blood from other tissues. Furthermore, apart from alignment and preservation of blood fluidity, it has multifunctional action in the delivery of nutrients and water, keeping of metabolic homeostasis, trafficking of cells, activation of immune responses, and angiogenesis [133,134]. In the TME, some factors such as chronic growth factor stimulation and hypoxia can result in endothelial dysfunction. There is intense evidence explaining that these abnormalities cause tumour progression [135]. Given that EC cells can play a role in suppressing the immune response due to inhibitory factors, this negative feedback is mostly done through an effect on immune cells such as myeloid cells, Tregs, and effector T cells [136]. Some of the tumour microenvironment components and their role in tumour development are illustrated in Figure 2.
Ser69 phosphorylation of TIMAP affects endothelial cell migration
Published in Experimental Lung Research, 2021
Nikolett Király, Csilla Csortos, Anita Boratkó
Endothelium regulates vascular function. It has a central role in hemostasis, inflammation, vasoregulation, angiogenesis, and vascular growth. Endothelial cells (EC) form a barrier between blood and the underlying tissue and its integrity is critical to proper tissue and organ function. . EC integrity depends on the structure of the cytoskeleton and cell-cell junctions. Organization of the cytoskeletal elements is flexible, it is highly adapted to extra- and intracellular signals which affect the phosphorylation state and eventually the actual conformation of cytoskeletal proteins. Equilibrium between contractile and tethering forces determines the actual shape, and the actual interactions of the cell with neighboring cells.1 Regulation of the phosphorylation level of adherent or tight junction, furthermore cytoskeleton and cytoskeleton-associated proteins is greatly clinically relevant, as these proteins are crucial in the EC barrier function.1–3 Both Ser/Thr and Tyr phosphorylation play a regulatory role in EC junction and cytoskeletal structures, and eventually, influence paracellular permeability.4