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The Beneficial Effect of Omega-3 PUFA and L-Arginine on Endothelial Nitric Oxide (NO) Bioavailability
Published in Robert Fried, Richard M. Carlton, Flaxseed, 2023
Robert Fried, Richard M. Carlton
Arterial blood vessels have three major structures: The innermost layer, the tunica intima (also called tunica interna), is simple squamous epithelium surrounded by a connective tissue basement membrane with elastic fibers. The middle layer, the tunica media, is primarily smooth muscle and is usually the thickest layer. It not only provides support for the vessel but also changes vessel diameter to regulate blood flow and blood pressure. The outermost layer, which attaches the vessel to the surrounding tissue, is the tunica externa or tunica adventitia. This layer is connective tissue with varying amounts of elastic and collagenous fibers. The connective tissue in this layer is quite dense where it is adjacent to the tunica media, but it changes to loose connective tissue near the periphery of the vessel.
Hyperglycemia Impairs Blood Vessel Function
Published in Robert Fried, Richard M. Carlton, Type 2 Diabetes, 2018
Robert Fried, Richard M. Carlton
As previously noted, arteries are made up of three major wall layers encircled by muscle rings. From the outside in, the tunica adventitia is made entirely of collagen; the middle layer, the tunica media, has an extra layer of smooth muscle that allows the vessel to increase or decrease in size; the tunica intima is the inner cell layer.
Atherosclerosis and Mechanical Forces
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
The atherosclerotic process develops within the arterial wall, with the participation of all its components. The arterial wall is composed of three layers: the tunica intima, the tunica media, and the tunica adventitia. The tunica intima is the innermost layer formed by a single stratum of endothelial cells (ECs) supported by an internal elastic lamina. Endothelial cells are in direct contact with the blood flow; in response to hemodynamic stimuli, ECs release a wide range of factors acting in an autocrine and paracrine manner to maintain vascular homeostasis (Deanfield 2007). A loss of normal endothelial function is believed to be a key event in the initiation of the atherosclerotic process (Bonetti 2003). The tunica media consists of layers of smooth muscle cells (SMCs) that are organized in groups of cells oriented perpendicularly to the longitudinal axis of the artery and reinforced by a network of type III collagen fibers to prevent excessive wall stretching. Each cellular group is embedded into a system of similarly oriented elastic fibers that endow the artery with compliance and recoil during the cardiac cycle (Clark 1985 and 1979). The tunica adventitia, or the outermost layer, is made up of connective tissue containing a network of vasa vasorum and nerves mediating the vascular tone.
Berberine alleviates monosodium glutamate induced postnatal metabolic disorders associated vascular endothelial dysfunction in newborn rats: possible role of matrix metalloproteinase-1
Published in Archives of Physiology and Biochemistry, 2022
Abeer A. Abo Zeid, Ibrahim Rowida Raafat, Abeer G. Ahmed
Light microscopic examination of H&E stained aortic sections of control rats, revealed three layers from inward outward. The 1st layer was the tunica intima with its regular lining endothelial cells. The next layer appeared was the tunica media that showed smooth muscle cells with their nuclei appeared dark blue arranged in concentric layers alternating with collagen and elastic fibres. The third layer was the tunica adventitia which consisted of loose connective tissue containing elastic and collagen fibres (Figure 2(A)). Mallory’s trichrome stained sections showed regular distribution of connective tissue in the intima and in the media (Figure 2(B)).Sudan III stained sections of control showed only one orange brown fat cell in the media (Figure 2(C)). Also, Van Geison stained sections of control showed regularly arranged brown elastic fibres all through the media (Figure 2(D)).
Characterization and in vivo study of decellularized aortic scaffolds using closed sonication system
Published in Organogenesis, 2019
Aqilah Hazwani, Munirah Sha’Ban, Azran Azhim
For a more complete verification of ECM structure, collagen and elastin structure in native tissues and aortic scaffolds were identified by PSR and VVG staining, respectively. For elastic fibre detection, native, immersed and sonicated aortic samples were stained with VVG as shown in Fig. 6. Tunica media were characterized by a high amount of elastic fibres, whereas tunica adventitia and intima had few elastic fibres. The staining revealed that sonication and immersion treatment could maintain elastic fibres of aortic tissues although some differences existed among the treatments. In native aortic tissues, a small wave-like shape of lamellar elastic fibrils was crimped and stained as dark purple while collagen fibres that lie between the two fenestrated sheets of elastin were stained as pink. In contrast, the lamellar elastin fibrils of the decellularized aortic scaffolds were straight and had a large wavelike shape. The inter-lamellar spaces of the decellularized aortic scaffolds were enlarged because of the loss of inter-lamellar fine elastic fibrils and collagen fibres. The lamellar elastin fibrils at the tunica intima surface of the immersed aortic scaffolds with 2% SDS appeared to be fragmented.
Four-day pulse of sodium cromoglycate modulates pulmonary vessel wall remodeling during 21-day hypoxia in rats
Published in Experimental Lung Research, 2018
Tomáš Novotný, Jiří Uhlík, Luděk Vajner
In the H21 group, thickness of tunica media and tunica adventitia increased in comparison to the N21 and N21CS groups (Figures 3, 4). Hypertrophy of tunica media (Figure 5 B-m) is symmetrical. Tunica adventitia usually forms asymmetrical parts with evident increase of vasa vasorum (Figure 5 B-c). Collagen fibers are in two layers in tunica adventitia; inner one (Figure 5 B-b) with thick and numerous fibers; outer one (Figure 5 B-c) with thin and sparse fibers. In this group, these two layers intermingle at the contact face. Myofibroblasts reside again at the periphery of the outer layer of tunica adventitia (Figure 6 B). Endomysium is conspicuously rich in collagen III (Figure 7 B-m); reticular fibers are diffusely numerous in tunica adventitia (Figure 7 B-b,c). Elastic membranes of tunica media are branched and split in some places. Number of thin elastic fibers in the inner part of tunica adventitia increases.