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At least 433 records · Page 24Linked to original sources
PubMed1992

The human carotid atherosclerotic plaque stimulates angiogenesis on the chick chorioallantoic membrane.

The chick chorioallantoic membrane was used to determine whether the carotid atherosclerotic plaque stimulates angiogenesis. Carotid endarterectomy specimens (1 mm3) with fibromuscular plaque (n = 8) and complicated plaque (n = 11) were implanted on the membrane on day nine of incubation and the response evaluated on day 11. Following fixation in situ with 10% formalin the angiogenic response was evaluated by: (1) examining whole membrane mounts, (2) quantitatively from a vascular density index and (3) from a histological study. Unmanipulated chorioallantoic membrane (n = 11) and plaque boiled prior to implantation (n = 6) served as controls. The vascularity of whole mounts of both fibromuscular and complicated plaque was greater than the controls. Vessel density of the membrane was estimated by counting the number of vessels intersecting four concentric circles (144.5 mm total circumference) placed on the formalin fixed membrane. The vascular density index due to the fibromuscular plaque (390.6 +/- 8.3) and complicated plaque (391.0 +/- 14.9) were similar (P greater than 0.9) but were significantly greater (P less than 0.001) than the unmanipulated membrane (327.9 +/- 5.6) or after treatment with the boiled plaque (283.8 +/- 15.6). Transforming growth factor beta 1 confirmed the validity of the experimental model to study angiogenesis. The histology of the chorioallantoic membrane due to either type of plaque was similar. Numerous vessels surrounded the plaque, and intraplaque vessels containing nucleated chick erythrocytes were observed. Although scattered vessels surrounded the boiled plaque, intraplaque vessels were not observed. This study demonstrates that the atherosclerotic plaque has angiogenic properties that may account for the increase in vasa vasorum that is associated with the plaque.

Allantois↗
PubMed1993

Medial thinning and atherosclerosis--evidence for involvement of a local inflammatory effect.

Medial attenuation in relation to atherosclerotic plaques is poorly understood. We investigated the potential role of a local inflammatory response. Segments of carotid artery and descending aorta were studied. The samples were grossly normal (n = 10), presented circumscribed atherosclerotic plaques (n = 19) or confluent atherosclerotic lesions (n = 8). Tissues were fixed in formalin or snap frozen in liquid nitrogen. Sections were stained with conventional staining methods and immunohistochemically (smooth muscle cells, macrophages, and T and B lymphocytes). Medial thickness was measured with an ocular micrometer; inflammatory infiltrates and medial vascularization were assessed semiquantitatively. Increasing severity of intimal lesions was accompanied by a significant increase in medial inflammation and vascularization and by a significant decrease in medial thickness. The inflammatory infiltrates in the media consisted of macrophages and T lymphocytes, localized predominantly around vasa vasorum. In advanced atherosclerosis they spread more diffusely. Inflammatory cells of the intimal atheroma also penetrated the media. At sites of inflammation the media contained HLA-DR positive smooth muscle cells with loss of collagen. The media in confluent atherosclerosis was almost devoid of smooth muscle cells, with loss of collagen and focal fibrosis. We postulate that the inflammatory reaction in the media relates to atherosclerosis, has a remodelling effect on medial tissues and may cause medial attenuation.

Aged↗
PubMed1985

A dissecting aneurysm in the bulbus arteriosus of a brook stickleback, Culaea inconstans.

In the bulbus arteriosus of an adult, male brook stickleback, C. inconstans, one of 100 caught in July 1982 from Lake 200, near Erickson, Manitoba, Canada, there was a dissecting aneurysm similar to those in the human aorta. The vessel also showed the classic signs of Erdheim's "idiopathic cystic medionecrosis", but its lumen was dilated and the lesion could thus also be regarded as a fusiform aneurysm. In the proximal half of the bulbus the endothelial lining was torn transversely and blood had extended into the middle layer of the wall to create 2 concentric and longitudinal channels which re-entered the lumen distally at approximately the mid-point of the bulbus. Except near the bulbar-aortic junction, the amount of elastica and (probably) smooth muscle was drastically reduced, the wall was infiltrated with amorphous deposits of mucoid substances, there were focal, cyst-like areas, and the normally tall and intensely PAS-positive, endothelial cells were flattened and poorly staining. There was no evidence of cystic medionecrosis in the bulbus arteriosus of other fish without dissecting aneurysms. This is thought to be the first report of a dissecting aneurysm in any lower vertebrate. Evidently, such an aneurysm can occur in a vessel without vasa vasorum, and in a very small animal (48 mm long), where the wall tension in its blood vessels must be extremely low compared with that in the human aorta.

Aortic Dissection↗
PubMed1989

Morphological changes of the aorta and pulmonary artery in thoroughbred racehorses.

The aorta and extrapulmonary artery were examined pathologically in 33 thoroughbred racehorses ranging in age from 1 to 5 years. Many of the great vessels of these horses exhibited degenerative or sclerotic changes in the media with neither lipidosis nor deposits of cholesterol. The severe lesions were predominantly observed at the bifurcation of the pulmonary artery. The severity of the lesions in both the aorta and pulmonary artery appeared to be associated with the racing career of the racehorse rather than with increasing age. Histopathogenetically, the medial changes in the great vessels were probably initiated by ischaemia and/or oedema in their walls due to pathological disturbances of the vasa vasorum and their vasomotor nerves. Whether hypervitaminosis D plays a role in the condition in racehorses needs to be determined by further study.

Aging↗
PubMed1984

Innervation of syngeneic vein grafts in the rat. The regeneration of adrenergic nerves.

Regeneration of adrenergic nerves was studied sequentially in segments of the supradiaphragmatic inferior vena cava transplanted from one rat into the abdominal aorta of another of the same inbred strain. Nontransplanted vein segments were examined as controls. The adrenergic nerves were demonstrated by using the glyoxylic acid-induced fluorescence method and the formaldehyde-induced fluorescence method for the demonstration of cathecholamines. A total of 16 syngeneic grafts were examined 3, 5, 8, 16, 27, and 32 weeks after transplantation. Three additional grafts were wrapped inside a silicone tube during the operation to prevent regeneration of nerves from the surroundings. These rats were then killed 8 weeks after the operation. In the control specimens the supradiaphragmatic inferior vena cava was innervated with a rather dense plexus of adrenergic nerves showing varicosities. No nerves were seen in the 3-week-old grafts. In the 5-week-old grafts some sparsely distributed solitary nerve fibres were seen. In the 8-week-old grafts sparsely distributed regenerated nerves reinnervating the vasa vasorum and nerve plexa were observed. The 16-, 27-, and 32-week-old grafts showed rather poorly innervated areas and areas where the nerve plexus was dense. One graft showed very dense reinnervation with morphologically abnormal adrenergic nerves forming "droplet fibers" and showing dense accumulations of catecholamines. The grafts surrounded with silicone tubes had no adrenergic nerves and showed only some regenerated nerves crossing the suture line. The results of the present study indicated that syngeneic inferior vena cava transplanted into the abdominal aorta will be reinnervated with adrenergic nerves. The pattern of the nerve regeneration remains incomplete and patchy.

Animals↗
PubMed1989

Morphogenesis of intimal thickening in nonspecific aortoarteritis.

Hyperplastic intima in nonspecific aortoarteritis was investigated immunomorphologically and by means of electronmicroscopic autoradiography. The cellular composition of the involved vascular wall was studied by the method of alcohol-alkaline dissociation. The prevalence of elongated cells with side processes and stellate cells in thickened intima was shown. These cells are characterized by essentially intensive RNA synthesis and, according to the electron microscopic data, can be regarded as pericytes. A significant amount of capillaries and precapillaries in thickened intima was visualized. Distribution of laminin and type IV collagen coincided with localization of the basal membrane of the vasa vasorum and with that of microvessels growing in the intima. Considered together, these data suggest that pericytes that surround a capillary/precapillary network may play a significant role in the morphogenesis of vascular transformation in nonspecific aortoarteritis intimal thickening.

Adolescent↗
PubMed1992

Pulmonary vascular involvement in sarcoidosis: a report of 40 autopsy cases.

We examined pulmonary vascular involvement in 40 autopsy cases of sarcoidosis. In these cases granulomatous involvement was observed at all levels from large elastic pulmonary arteries to venules, and venous involvement was more prominent than arterial involvement. The extent of granulomatous vascular involvement was related to that of parenchymal granuloma. No significant difference was found between upper and lower lobes in the incidence of granulomatous vascular involvement. The distribution of granulomata in the blood vessels was segmental and adventitial, and medial involvement was prominent in the larger vessels. Healed lesions of granulomatous vascular involvement also were observed at various levels in blood vessels. Prominent granulomatous involvement was found in the lymphatic capillaries and collecting lymphatic vessels in lungs with sarcoidosis. Serial sections of the lungs demonstrated interstitial granuloma directly connecting the lymphatic capillaries around small blood vessels. Granulomatous involvement in vasa vasorum and lymphatic capillaries is likely to be an important factor in the pathogenesis of granulomatous vascular involvement in lungs with sarcoidosis. The present study suggests that granulomatous vascular involvement and its sequelae may contribute to the development of pulmonary sarcoidosis.

Aged↗
PubMed1995

Intimal neovascularization in human coronary atherosclerosis: its origin and pathophysiological significance.

To investigate the histopathological characteristics of the newly formed vessels in the atherosclerotic intima of human coronary arteries, we conducted postmortem angiography in 31 cases, including 11 with myocardial infarction. Vessels were examined three-dimensionally under the stereoscope. In addition, we evaluated 25 anterior descending coronary arteries unrelated to the occurrence of myocardial infarction by light microscopy using 3-mm stepwise sections and 5-microns serial sections. Histological alterations were analyzed morphometrically to determine the correlation between the degree of intimal neovascularization and the growth of the endothelium into the atherosclerotic intima from the adventitia or lumen. There was a significant positive correlation between the density of new vessels in the intima and the incidence of luminal stenosis, the extent of chronic inflammatory infiltrate, the formation of granulation tissue, or the atheromatous changes, whereas the vascular density decreased in the extensively hyalinized and calcified intima. The newly formed intimal vessels originated mainly from the adventitial vasa vasorum and also partly from the proper coronary lumen. The intimal vessels that originated from the adventitia occurred approximately 28 times more frequently than those that originated from the luminal side. The frequency of former vessels increased as the luminal stenosis became more severe, whereas the latter vessels were found most frequently in the presence of 40% and 50% stenosis. Vessels originating from the proper lumen were more often associated with fresh or old hemorrhage. We conclude that intimal neovascularization largely originates from the adventitia and is closely associated with the extent of coronary stenosis and the histological inflammatory reaction.

Adult↗
PubMed1985

The adrenergic innervation of pulmonary vasculature in the normal and pulmonary hypertensive rat.

It would appear that susceptibility to chronic proliferative pulmonary hypertension in response to chronic alveolar hypoxia is most severe in species in which adrenergic innervation of pulmonary arteries is reduced or lacking. Intrapulmonary arteries of the rat have been reported to lack adrenergic innervation by some workers but not others. Since the rat develops severe proliferative pulmonary hypertension in response to prolonged alveolar hypoxia, the different divisions of the lung vasculature of Sprague-Dawley rats were thoroughly examined to determine the presence or absence of an adrenergic innervation. The degree of innervation in normal rats was compared with that of rats developing pulmonary hypertension. Both in normal and experimental pulmonary hypertensive rats the pulmonary arteries, all their branches and the small pulmonary veins with a smooth muscle media were found to be devoid of adrenergic innervation. In contrast, the cardiac-like muscle in the media of large pulmonary veins, the bronchial arteries and the vasa vasorum of larger vessels were richly innervated by adrenergic nerves. Thus the increase in medial smooth muscle which occurs in pulmonary arteries during chronic alveolar hypoxia is independent of a pre-existing adrenergic innervation or of such an innervation newly derived from that of adjacent vessels or structures. This is in contrast to systemic vessels where it has been suggested that increased adrenergic activity and density of innervation may augment hypertrophy of the media in hypertensive animals. Adrenergic nerves are suggested to have a protective action on pulmonary vessels.

Adrenergic Fibers↗
PubMed1995

Immunohistochemical localization of adrenomedullin in canine heart and aorta.

Adrenomedullin (ADM) is a new endogenous hypotensive and vasorelaxing peptide that may play an important role in the regulation of cardiovascular function. Although ADM was originally isolated from pheochromocytoma, ADM-like immunoreactivity has also been widely detected in various tissues, including the cardiovascular system. Based upon the reports that ADM mRNA and ADM-like immunoreactivity are present in the heart, the present study was designed to investigate the immunohistochemical localization of ADM in the canine heart and aorta. In the canine heart, immunohistochemical examination revealed positive immunostaining within the myocardia in both atria and ventricles. ADM immunoreactivity was observed within the cytoplasm of myocardium, and was widely distributed in the peripheral cytoplasm. ADM immunoreactivity was more intense in the atria than in the ventricles. In the canine aorta, vascular smooth muscle cells of the aorta and vasa vasorum were also immunopositive for ADM. ADM immunoreactivity was mostly localized in the perinuclear position within the smooth muscle cells. There was no immunoreactivity in endothelium, endocardium, epicardium, adventitia, or connective tissues. The current study demonstrates for the first time that immunoreactive ADM by immunohistochemistry is present in the cardiovascular system. As ADM has hypotensive and vasorelaxing actions and circulates in the body, ADM is a cardiovascular peptide hormone that may play an important role in the regulation of cardiovascular system.

Adrenomedullin↗
PubMed1990

Quantitative immunocytochemical studies of endogenous albumin in rat aortic endothelial and mesothelial cells.

Endogenous albumin was revealed over cellular structures of rat ascendent aorta endothelia and mesothelium, with high resolution and specificity, by applying the protein A-gold immunocytochemical approach. This approach allows albumin distribution to be studied under steady-state conditions. The cellular layers evaluated were the aortic endothelium, the capillary endothelium (vasa vasorum), and the mesothelium externally lining the aorta at this level. Gold particles, revealing albumin antigenic sites, were preferentially located over plasmalemmal vesicles and intercellular clefts of endothelial and mesothelial cells, though with different labeling intensities. The interstitial space was also labeled. Morphometrical evaluation of plasmalemmal vesicles demonstrated a higher surface density for these structures in capillary endothelial cells (12%) compared with those in aortic endothelial (5%) and mesothelial cells (2%). Quantitation of gold labeling intensities over these structures revealed a higher labeling over plasmalemmal vesicles of capillary endothelium than over those of aortic endothelium and mesothelium. This result, together with the higher surface density of plasmalemmal vesicles found in capillary endothelium, suggest an important role of these structures in the transendothelial passage of endogenous albumin, particularly for capillary endothelium. On the other hand, labeling densities over mesothelial clefts were found to be higher than those of capillary and aortic endothelia. Results from this study concur with the proposal of a differential passage of albumin according to the cell lining considered, and suggest to a role for mesothelial intercellular clefts in contributing to the presence of albumin in interstitial spaces.

Albumins↗
PubMed1993

Substance P innervation of equine synovial membranes: joint differences and neural and nonneural receptor localizations.

Substance P (SP) immunocytochemistry and receptor autoradiography were used to define the innervation of the equine synovial membrane of joints equivalent to the wrist and knuckle of man. SP-immunoreactive fibers were mainly concentrated around blood vessels in the subsynovial layer, although not exclusively, while in the more distal joint, SP fibers were more frequently seen in the synovial surface layer. Iodinated SP receptor autoradiography studies revealed silver grain concentrations in the advential layer of blood vessels associated with the vasa vasorum, on the vascular endothelium and in the synovial surface. These findings suggest that SP has various sites of action within the synovial membrane, each of which may contribute both a sensory function and a different component of the inflammatory process to the joint.

Animals↗
PubMed1979

Anoxemia as the cause of death in shock.

The case is presented that both hemorrhagic and septic shock are due to an inadequate oxygen supply to mitochondria of vascular muscle cells in peripheral circulatory beds. Mitochondria disintegrate in the presence of severe hypoxia; this is a normal response which does not, per se, indicate generalized cell damage. Irreversible shock follows when appreciable numbers of the muscle mitochondria become non-functional. The ATP available from glycolysis is inadequate to resynthesize the mitochondrial apparatus and oxygen cannot be used by the damaged mitochondria to produce the needed ATP through oxidative phosphorylation. In the absence of adequate ATP, the tone of these peripheral vessels must fall, leading to irreversible systemic hypotension and death. In hemorrhagic shock, mitochondrial hypoxia of smooth muscle cells is produced by decreased perfusion of the vasa vasorum in the constricted peripheral vessels; in septic shock there is direct competition for oxygen between bacterial cytochromes and muscle mitochondria.

Adenosine Triphosphate↗
PubMed1980

Arterial vasoconstriction: a possible pathogenetic factor in the process of atherosclerosis.

The nutritional supply of arteries with a wall thickness of more than 0.5 mm takes place partly by diffusion from the lumen of the artery and partly from the adventitia through the vasa vasorum. The diffusion capacity is partially dependent upon the wall thickness and the intravascular pressure. During vasoconstriction both the wall thickness and the work of the muscle cells of the media are increased. The metabolic demands thus become greater at the same time as the nutritional supply deteriorates. Arterial vasoconstriction may cause a change in metabolism in the media, leading to a primary lesion in the arterial wall.

Angiography↗
PubMed1984

Fibromuscular dysplasia of arteries: a spastic phenomenon?

Arterial fibrodysplasia is principally observed in renal and carotid arteries: the disease is a systemic, acquired one related to ischemia of the muscular cell of the media, by obstruction of the vasa-vasorum. Its histological identification in very rare cases of spastic arteries in cases of chronic ergotamine or methysergide intoxication lead me to consider that fibrodysplasia could be due to chronic, repeated, discontinuous and subobstructing spasms, favoured by the various etiological co-factors already known.

Arterial Occlusive Diseases↗
PubMed1994

Aortic intramural hemorrhage visualized by transesophageal echocardiography: findings and prognostic implications.

OBJECTIVES: This study describes the transesophageal echocardiographic and follow-up findings in patients with aortic intramural hemorrhage. BACKGROUND: Localized aortic intramural hemorrhage resulting in layered thickening of the aortic wall seems to represent a variant of acute aortic dissection without communication or a typical moving intimal flap. In autopsy studies this variant, attributed to a rupture of the vasa vasorum, has been described in 5% to 10% of patients with dissection. METHODS: In a prospective transesophageal echocardiographic study in patients with aortic dissection performed between 1986 and 1991, the diagnosis of intramural hemorrhage was established in 15 of 114 patients and either confirmed anatomically (7 patients) with an additional diagnostic imaging technique or on the basis of clear follow-up changes (8 patients). RESULTS: Elderly patients (mean age 70 years) with a history of hypertension were affected by this variant of dissection. The ascending aorta was involved in 3 patients and the descending aorta in 12. The longitudinal extent varied between 3 and 20 cm, and wall thickness varied between 0.7 and 3 cm. Classic aortic dissection developed in five patients (33%) and rupture in four (27%). Regression of aortic wall thickening was noted in two patients, whereas three patients became asymptomatic without apparent wall changes (33%). Surgery was performed in 5 patients, whereas medical therapy was continued in 10. During a mean follow-up period of 11 months, eight patients (53%) died because of complications of the aortic disease. CONCLUSIONS: Intramural hemorrhage represents a variant of aortic dissection and may be an early finding in patients who develop classic aortic dissection or rupture. Transesophageal echocardiography is an excellent method for the detection of intramural hemorrhage and for monitoring these patients.

Aged↗
PubMed2004

Role of surrogate markers in assessing patients with diabetes mellitus and the metabolic syndrome and in evaluating lipid-lowering therapy.

Diabetes mellitus and the metabolic syndrome (MS) are reaching epidemic proportions in the United States, and cardiovascular disease continues to be the leading cause of death among patients with diabetes. A range of noninvasive screening tools may help reduce the morbidity and mortality of patients with diabetes because of early detection of subclinical cardiovascular disease and active monitoring of the effectiveness of therapy. Surrogate markers of subclinical disease include conventional and contrast-enhanced ultrasound imaging of carotid artery intima-media thickness (c-IMT), 2-dimensional echocardiography, coronary artery calcium imaging, cardiac magnetic resonance imaging, ankle-brachial indices, and brachial artery reactivity testing. Because these noninvasive imaging tools are relatively comfortable and entail relatively low risk to the patient, they are ideal for initial screening and for the repeated imaging that is required for monitoring the effectiveness of therapy. Moreover, when used in large numbers of patients with diabetes, prediabetes, and the MS, these imaging tools may be useful in developing and validating thresholds for the use of lipid-lowering therapy as well as clear therapeutic goals for this population. In addition, contrast-enhanced c-IMT scans now produce real-time images of the vasa vasorum and neovascularization of atherosclerotic plaque, potentially causing a paradigm shift in our view of the genesis of atherosclerosis and affecting treatment options for all populations. Thus, surrogate markers may not only help improve individual patient outcomes, they also may help direct scarce medical resources to maximize medical benefits, improve overall medical care, and minimize costs and untoward side effects.

Adult↗
PubMed2005

Internal thoracic artery: to skeletonize or not to skeletonize?

The internal thoracic artery has been the most reliable graft material used in coronary artery bypass grafting with an excellent long-term patency rate. Complete myocardial revascularization with internal thoracic arteries improves long-term survival and decreases the rate of repeat operations compared with vein grafts. Adequate length of the graft in coronary artery bypass graft surgery is essential for providing complete arterial revascularization. In the last decade or so, technique of skeletonization of internal thoracic artery has been proposed to achieve extra length. Skeletonization of the internal thoracic artery allows the preparation of longer conduits with a superior free flow and can reduce the incidence of postoperative pulmonary and sternal complications. However, concerns about vasoreactivity of skeletonized internal thoracic artery grafts, the functional consequences of surgical trauma, the possible loss of innervation, and vasa vasorum perfusion in the skeletonized conduits have prevented this technique from being universally accepted. Presently available evidence from retrospective studies (level 3 evidence) suggests that skeletonization is a safe and effective technique for myocardial revascularization. However, there is a need for conducting multicenter, randomized controlled trials comparing the skeletonized and pedicled internal thoracic arteries with special emphasis on long-term patency to conclusively validate the safety and efficacy of skeletonization technique.

Angioplasty, Balloon, Coronary↗