Elastic lamina

The normal arterial wall consists of the intima, media, and adventitia, as illustrated in Fig. 4—3A. The endothelium is located in the intima and consists of a layer of endothelial cells that line the lumen of the artery and form a selective barrier between the vessel wall and blood contents. The internal elastic lamina separates the intima and media, where vascular smooth muscle cells are found. The vascular adventitia comprises the artery s outer layer. Atherosclerotic lesions form in the subendothelial space between the endothelial cells and internal elastic lamina. 

Pulmonary arterial effects. Cigarette smoke, administered to 2- and 3-month-old rats at a dose of one cigarette 10 times a day, increased significantly the volume fractions of the fibroblasts, the collagenous bundles, and the elastic laminae of the pulmonary arteries. The volume fractions of smooth muscle cells and the remainder were decreased significantly in both groups compared to controls. An increase in the stiffness of the pulmonary arteries was found in both the 2- and 3-month smoke-exposed rats . ... 

The heart may be enlarged with left ventricular hypertrophy, particularly in cases which have exhibited hypertension during life. Metastatic calcification of the valves and of the myocardium may be present, explaining no doubt the cardiac murmurs which may have been detected clinically in such cases. Occasionally, medullary proliferation of large arteries and, in the smaller arteries, fragmentation of the intimal elastic lamina has been reported, in one case with impregnation with calcium salts. Local calcification of the media of the middle cerebral artery has been described. 

Figure 9.3 Inhibition of intimal hyperplasia by resveratrol in rabbits subjected to endothelial injury by denudation. Groups of eight New Zealand white rabbits, weighting 2.2 to 3.6 kg, were assigned randomly to control (untreated) (M), low (2 mg/kg/d) (L), and high dose (4 mg/kg/d) (H) resveratrol treatment, which was administered intragastrically for 5 weeks beginning 1 week before surgery. A 2-cm segment of injured iliac artery was excised, fixed in 4% paraformalin, embedded in paraffin, and sectioned at5-mm intervals from the proximal to the distal end. Representative sections were stained with hematoxylin/eosin. The external and internal elastic lamina were manually identified. Intimal proliferation index (IPI) was defined as the ratio of intimal area to [intimal+medial] area relative luminal area (RLA) was defined as the ratio of luminal area to [luminal+intimal+medial] area.

Figure 14.29 Internal elliptical crack in an elastic lamina subjected to a stress a. Distribution of local stresses in the positive x direction.

Insulin responsive substrate (iRS), 179 integrins, 135-136, 339,534 Iniecnal elastic lamina, 359, 360 Intervention study, 964 Intestinal tract... 

Figure 6 Effect of D-BSA, a diazeniumdiolated bovine serum albumin derivative, in promoting healing of balloon-injured pig coronary arteries. Shown are representative cross-sections of arteries taken two weeks after angioplasty from pigs dosed immediately before 30% balloon overstretch via intrapericardial instillation with 400 mg of underivatized BSA (a), 40 mg of D-BSA ( >), and 400 mg of D-BSA (c). Arrows denote ruptured ends of the internal elastic lamina for each vessel shown. [Reprinted from Reference 8 with permission.]... 

The normal artery wall is composed of three layers intima, media, and adventita (Figure 20-10). On the luminal side, the intima contains a single layer of endothelial cells. These cells permit passage of water and other substances from blood into tissue cells. On the peripheral side, the intimal layer is surrounded by a fenestrated sheet of elastic fibers (the internal elastic lamina). The middle portion of the intimal layer contains various extracellular components of connective tissue matrix and fibers and occasional smooth cells, depending on the type of artery, and the age and sex of the subject. 

The adventitia is separated from the media by a discontinuous sheet of elastic tissue (the external elastic lamina) and consists of smooth muscle cells, fibroblasts, collagen fibers, and glycosaminoglycans. This layer is supplied with blood vessels to provide nutrients. 

Cavernous angioma CNS Clusters of abnormal, often fibrotic or hyalinized vessels with elastic lamina and without intervening brain tissue... 

Healed lesions—nodular fibrosis and loss of internal elastic lamina... 

The normal artery is composed of three distinct layers (Fig. 34.21). That which is closest to the lumen of the vessel, the intima, is lined by a monolayer of endothelial cells that are bathed by the circulating blood. Just beneath these specialized cells lies the subintimal extracellular matrix, in which some vascular smooth muscle cells are embedded (the subintimal space). The middle layer, known as the tunica media, is separated from the intima by the internal elastic lamina. The tunica media contains lamellae of smooth muscle cells surrounded by an elastin- and collagen-rich matrix. The external elastic lamina forms the border between the tunica media and the outermost layer, the adventitia. This layer contains nerve fibers and mast cells. It is the origin of the vasa vasorum, which supply blood to the outer two thirds of the tunica media. 

SMC (lamellar) ceils are co-segregated in the tunica media [8,9]. The former cell type lacks a basement membrane, myofilaments and dense bodies. In addition, bovine aorta and pulmonary artery SMC can have distinct structural profiles as regards shape, location, cell orientation and pattern of elastic laminae [10-13]. 

Three continous layers can be shown in the wall of embryonic human aorta. The innermost layer contains undifferentiated SMC, the intermediate layer consists of differentiated cells. In the outermost layer, possibly destinated to become the tunica adventitia, there are fibroblasts/generic mesenchymal cells [22]. At the same time, SMC become linked to the developing elastic laminae by bundles of microfibrils [23], giving rise to contractile-elastic units , i.e., a continous line of structures that link adjacent elastic laminae. Contacts between differentiating SMC and endo-... 

The basic structure of arterial vessels is largely developed at birth [25]. The cytoplasm of medial SMC contains the apparently complete array of filaments and subceDular structures of adult-type SMC [26]. As to the extracellular components, elastin fiber content increases during prenatal and postnatal periods. In utero, this occurs particularly with the slowing down of proliferation rate of SMC, concomitantly with the beginning of the fetal phase [27] and postnatally in response to changing hemodynamic conditions and wall stress [28,29]. Elastic fibers continue to develop until complete elastic laminae are formed (about 4 weeks from birth [30]). 

Davis EC (1993) Smooth muscle cell to elastic lamina connections in developing mouse aorta. Role in aortic medial organization. Lab Invest 68 89-99... 

Van der Lei, B., Wildevuur, C. R. and Nieuwenhuis, R, Compliance and biodegradation of vascular grafts stimulate the regeneration of elastic laminae in neoarterial tissue An experimental study in rats, Surgery, 99, 45, 1986. Ratcliffe, A., Matrix Biology, 8, 1, 2000. 

Wall morphology Complete tunica adventitia, external elastic lamina, tunica media, internal elastic lamina, tunica intima. ... 

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