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PubMedDate not supplied

An experimental study of endovascular stenting with special reference to the effects on the aortic vasa vasorum.

PURPOSE: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. METHODS: Eight bare stents and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4-45 weeks after stent placement. The vasa vasorum was evaluated by microstereoscopy with vascular casting, and the histopathology of the aortic wall was examined by light microscopy. RESULTS: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media were avascular. In the stented segment, vascular dilatation and proliferation of vasa vasorum, medial atrophy, and intimal hyperplasia were observed, more prominent for covered stents than for bare stents. CONCLUSION: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, probably due to hypoxia in the aortic wall.

Animals↗

PubMed1985

Relationship between vasa vasorum and blood flow to vein bypass endothelial morphology.

In order to define the respective roles of the vasa vasorum blood supply and intraluminal arterial blood flow in maintaining the endothelial integrity of in situ vein bypasses, we have carried out two separate but interrelated experiments in a canine model. In vivo studies on eight dogs demonstrated that even in the absence of intraluminal blood flow the vasa vasorum maintained endothelial integrity and also showed that the endothelium was very sensitive to the loss of the vasa vasorum blood supply. In a second group of experiments on 14 in situ vein bypasses we studied the effect of division of the vasa vasorum immediately after arterialization of the bypass. This experiment showed that arterialization of the vein maintained endothelial integrity despite division of the vasa vasorum.

Animals↗

PubMed1992

The vasa vasorum of the rabbit carotid artery.

The anatomy of the vasa vasorum of the carotid arteries was assessed by light and electron microscopy in a series of 25 New Zealand White male rabbits. The low viscosity acrylic resin, LR White, was used to cast the microvasculature. The carotid artery was found to have an endothelial monolayer placed directly upon a broad fenestrated internal elastic lamina. The media consisted of 12-18 laminae comprised of smooth muscle cells, elastin, collagen and ground substance. Vasa vasorum were confined to the adventitial layer, with no penetration into the media. They arose directly from the lumen of the carotid artery in addition to the arterial branching points. The potential role of the vasa vasorum in the aetiology of atherosclerotic plaques is discussed.

Animals↗

PubMed1997

Development of vasa vasorum in the arterially implanted autovein bypass graft and its anastomosis in the dog.

Using stereomicroscopy, light microscopy, and scanning electron microscopy, we investigated the development of vasa vasorum in the proliferated neointima of the autovein graft and its anastomoses implanted in the canine femoral artery against a background of poor distal runoff. In the stereomicroscopic examination, a microfil silicone rubber compound (MF) was injected transluminally or via perivascular vasa, and the vascular specimen was prepared for clearing by immersion in a methyl-salicylate solution. Vessel interstices filled with MF were found adjacent to the suture materials within 5 days of grafting. Fourteen days after implantation, luminally originating vasa vasorum were often visible in the neointima along the suture line and distributed into the media and adventitia connecting to the original vasa vasorum. At 6 months or more after grafting, many orifices of luminally originating vasa vasorum were seen along the suture line of both proximal end-to-end and distal end-to-side anastomoses and distributed into the thickened neointima forming a vasa network when the neointima had proliferated to over 250 microm in depth. On the other hand, some clefts filled with MF were found in mural thrombi deposited on the vascular sinus of the graft within 5 days, and these appeared to be one of the sources of luminally originating vasa vasorum on the graft distant from the suture line. Moreover, the development of numerous vasa vasorum was constantly demonstrated in the neointima when it had proliferated to over 250 microm in depth.

Anastomosis, Surgical↗

PubMed2005

Types of vascular wall as related to vasa vasorum in common tree shrew (Tupaia glis).

Blood vessels of the common tree shrew (Tupaia glis) were embedded in Araldite, sectioned at 0.5-1 microm thickness, and observed with light microscope (LM). It was found that the vascular wall could be classified into three categories: (1) those with proper vasa vasorum (PVV); (2) those with collaborative vasa vasorum in perimural tissues; (3) those without vasa vasorum. The PVV were located in the the tunica media, between the tunica media and the tunica adventitia, and in the tunica adventitia of the vascular wall. On studying the vascular casts with a scanning electron microscope (SEM), it was noted that what appeared to be vasa vasorum did not always conform to those found under the LM. Furthermore, the PVV seen in a particular blood vessel among different tree shrews were not always related to intraluminal partial pressure of oxygen, vascular size, and thickness of the wall. In contrast, the results of this study indicate that the activeness of the vascular wall in varying the amount of blood flow to certain organs is an important factor that is associated with the existence, density, and distribution of the vasa vasorum.

Animals↗

PubMed1990

Rupture of coronary vasa vasorum as a trigger of acute myocardial infarction.

Some controversy has always existed regarding the presence and extent of the vasa vasorum--the nutrient vessels in the wall of the human aorta--in the coronary arteries. Now, cinemicrographic studies using silicone polymer injections in cleared human hearts have identified the vasa vasorum of coronary arteries, revealing evidence of neovascularization in the region of atherosclerotic plaques. These studies suggest an important role for the vasa vasorum in the pathogenesis of coronary atherosclerosis and its sequelae, especially intramural hemorrhage and vascular spasm. The wall of the human coronary artery in regions of atherosclerotic injury may be particularly rich in capillary vessels of the vasa vasorum. From this, the evidence suggests that with the morning increase in blood pressure, fragile neovascular structures of the vasa vasorum may be more prone to rupture and may be responsible, in part, for the circadian variation in myocardial infarction.

Adult↗

PubMed1989

The origin and distribution of vasa vasorum at the bifurcation of the common carotid artery with atherosclerosis.

The purpose of our study was to determine the origin and relation of vasa vasorum to atherosclerotic plaque at the bifurcation of the common carotid artery. We randomly selected 12 unembalmed adult human cadavers, 40-96 years of age. We prepared luminal casts of the arteries from eight cadavers and cleared the arteries from the remaining four cadavers. A network of vasa vasorum surrounding atherosclerotic plaque was observed in five luminal casts and in two cleared specimens; the vasa vasorum originated from the superior thyroid and ascending pharyngeal arteries. Three of the five luminal casts also demonstrated vasa vasorum arising directly from the internal carotid artery distal to the plaque. An extensive network of vasa vasorum was not observed in specimens from the five cadavers relatively free of gross atherosclerotic plaque. Our findings demonstrate the importance of the external carotid artery in giving rise to the vasa vasorum that supply the areas of atherosclerotic plaque.

Adult↗

PubMed1998

Linear and nonlinear elastic modelling of the deformation of vasa vasorum.

The authors present analytical and numerical approaches of the deformation of venous and arterial vessels vasa vasorum. An elastic behaviour of the vessel wall is supposed. It is shown that a normal range of intraluminar pressure induces a small deformation in the vasa vasorum in arteries. According to the nonlinear elastic behaviour, a larger deformation is induced in venous vasa vasorum is rapidly obtained. Increased pressure has serious consequences, especially on the flow in vasa vasorum and induces decrease of oxygen transport. This phenomenon could be one of the generating factors of atherogenesis and ischemia.

Animals↗

PubMed1988

The development of vasa vasorum of the human aorta in various conditions. A morphometric study.

The developmental behavior of vasa vasorum under various conditions was studied on the wall tissues of aorta and great arteries from 29 autopsy cases, where the length density (LA) of vasa vasorum in a unit area of wall was determined by morphometry. In a control group, LA was found to increase exponentially, along with increasing wall thickness D, among arteries from various anatomic sites of patients with greatly divergent ages. The regression curve crossed the x-axis at D = 0.6 mm, showing that arteries thicker than this have an auxiliary circulation by vasa vasorum. The LA was markedly high both in neonates and in patients with cyanotic heart anomaly, ie, in conditions where medial cells were sustained under reduced oxygen supply. Thus, vasa vasorum were shown to elongate their intramural segments in response to the changes of microenvironment in which the medial cells are placed, meeting the demand by the cells for increased supply of oxygen and nutrients.

Adolescent↗

PubMed1996

[Vascularization of the wall of the superficial veins. Anatomic study of the vasa vasorum].

INTRODUCTION: The blood vessel wall is almost always nourished by two ways; from the blood stream itself and through the outer part of the wall by vasa vasorum. AIM OF THE STUDY: The aim of this study was to demonstrate that this kind of nutrition is also available for the venous wall and to define the distribution pattern in superficial venous walls. MATERIALS AND METHODS: 50 long saphenous veins and 20 short saphenous veins latex or barium injections, dissections with magnifying glasses and microradiographies. Topographical evaluation of the origin of vasa vasorum. RESULTS: The results showed that vasa vasorum originated from perforating arteries coming from several levels and getting a lot of anastomosis. We showed that the main sources for the long saphenous vein are the external pudendal artery and descending artery of the knee and for the short saphenous vein, the short saphenous vein artery. In thrombosis and varicose veins, the vasa were strongly altered. CONCLUSION: This study outlines the fact that superficial veins are supplied by arterial and venous vasa vasorum, and the role of vasa vasorum must be considered when questioning the pathogenesis of varicose and post thrombotic disease.

Arteriovenous Anastomosis↗

PubMed2003

Vasa vasorum of the human great saphenous vein.

The distribution of the vasa vasorum of the human great saphenous vein (GSV) was studied on veins taken both post-mortem and peroperatively. It was found that the stems of feeding vessels approach the venous wall at intervals of 1.5-2.5 cm; their smaller branches first passed the fascial compartments of the GSV and then entered the adventitia at intervals of 0.5-1.5 cm on both the stem and the largest tributaries of the GSV. In the stem regions vasa vasorum arteries and veins ran together but, between neighboring stems, isolated venae vasorum were regularly found which opened individually into terminal segments of the largest tributaries of the GSV. Neither by dissection nor by injection methods were venae vasorum found to open directly into the lumen of the GSV stem. The total thickness of the media ranged between 500 and 1300 micro m, according to the state of constriction of the venous wall before fixation. Two structurally different layers of GSV tunica media were present: an inner loose layer and an outer dense layer, both of similar thickness. The innermost capillaries of the vasa vasorum network were found in all cases on the border between the two layers of media. No lymphatic was found in any of the layers of GSV wall. From the findings the authors recommend extremely careful dissection of the GSV wall during in situ grafting surgery, to ensure the best viability of the venous wall.

Aged↗

PubMed1982

Cerebrospinal fluid may nourish cerebral vessels through pathways in the adventitia that may be analogous to systemic vasa vasorum.

Cerebral blood vessels are devoid of vasa vasorum. Therefore, the authors have studied the microarchitecture of the adventitia of large feline cerebral vessels of the same size, in an effort of determine how the vessels are nourished. The cerebral vessels contain a rete vasorum in the adventitia that is permeable to large proteins and is in continuity with the subarachnoid space. This substructure may be analogous to the systemic vasa vasorum and may contribute to the nutrition of the cerebral arteries.

Animals↗

PubMed1987

Acute and long-term effects of massive balloon dilation on the aortic wall and vasa vasorum.

To investigate the acute and long-term effects on the vasa vasorum after massive overdilation, canine aortic segments were dilated with Gruentzig balloon catheters to more than 100% over normal size. In the acute study, the significant lumen increase was the result of intimal and medial rupture with stretching and thinning of the adventitia. In these areas, the vasa vasorum were stretched and severed, causing adventitial hemorrhage. In the chronic study, areas of previous subtotal wall rupture with adventitial thinning were repaired by scar tissue. This repair included formation of a neomedia, hyperplasia of the adventitia, and proliferation of the vasa vasorum. No progression of luminal dilatation was seen. This study showed that in subtotal aortic wall rupture, even a severely damaged adventitia is capable of preserving the lumen from further dilatation and rupture until healing. Blood flow to the damaged vessel wall was reestablished by revascularization via capillary budding in the aortic wall.

Angioplasty, Balloon↗

PubMed1997

Vasa vasorum of superficial collecting lymphatics of human thigh.

Collecting lymphatics were obtained from human thigh fat for light microscopy and tridimensional reconstruction at time of operation for varicose veins. No patient had lymphedema and routine sections showed no inflammation or notable pathologic alteration of the surrounding soft tissue. Abundant vasa vasorum was observed around the musculature of superficial collecting lymphatics of human thigh. Within intervalvular portions of the lymphatic collectors where the muscle coat was thicker and more compact, the vasa vasorum penetrated between smooth muscle cells and was in contact with the endothelium. In valvular portions of the collecting lymphatics where the muscle layer was thinner and more fragmented, there were fewer vasa vasorum. Tri-dimensional reconstructions of the collecting lymphatic wall showed two communicating plexi of vasa vasorum--one outside and the other inside the muscle layer. Arteries and veins of similar size did not have such an abundant vasa vasorum. The explanation for this difference may relate to the fact that a relatively low oxygen and nutrient content of lymph is insufficient to nourish the collecting lymphatic. Moreover, diffusion of nutrients from the external plexus is likely also impeded by the thickness and density of the muscle layer. The vasa vasorum deep in the muscular layer and in the subendothelial space probably sustain adequate nutrition and oxygenation to the collecting lymphatic.

Adipose Tissue↗

PubMedDate not supplied

Vasa vasorum changes following stent placement in experimental arterial stenoses.

PURPOSE: Experimental stenoses were created in canine aortae to compare the effects of stent placement and balloon angioplasty on the vasa vasorum. MATERIALS AND METHODS: A balloon-expandable Palmaz stent was placed in the proximal stenosis, and angioplasty was performed in the distal stenosis in each of eight dogs. Two dogs were killed at 4, 8, 12, and 18 months, respectively. Specimens were studied by means of microangiography, histology, scanning electronic microscopy, and Spalteholz technique. RESULTS: At up to 12 months, there was proliferation of the vasa vasorum and a rich plexus formed in each of the animals at each treated site. More vasa vasorum were seen after stent placement than after angioplasty. The new vessels were mainly venules located in the media. At 18 months, there was regression of the venules and the vasa vasorum distribution returned to baseline. CONCLUSION: The authors conclude that the effects of stents on the vasa vasorum are temporary.

Animals↗

PubMed1990

[Vasa vasorum of subcutaneous veins and lymph vessels].

After intraarterial ink-injection the vasa vasorum of veins and lymphatic vessels in adults, dead born children and fetuses were demonstrated micropreparatorily. In their walls the larger veins of the saphena system possess a capillary network corresponding to the connective tissue and muscle structures/patterns in the vessel wall. No vasa vasorum could be found in the subcutaneous veins less than 1 mm in diameter. The lymphatic vessels of the inner prefascial bundle show a one-dimensional capillary network in the outer layers of the wall. Like the vasa vasorum of the saphena system it develops in the second half of fetal life.

Adult↗

PubMed2000

Neutrophil and endothelial cell activation in the vasa vasorum in vasculo-Behçet disease.

AIM: The aim of this study was to analyse the immunopathological mechanisms of vasculo-Behçet disease, which were also compared to cases of Takayasu's arteritis and inflammatory aneurysm to evaluate differences in inflammatory mechanisms. METHOD AND RESULTS: We reviewed six cases of vasculo-Behçet disease, four of Takayasu's arteritis and seven inflammatory aneurysms which underwent surgical repair. Immunohistochemical studies were performed on paraffin-embedded tissue using a labelled streptavidin-biotin method, as was in-situ hybridization for Epstein-Barr virus. Microscopically, neutrophils and lymphocytes accumulated around the vasa vasorum. Neutrophils were prominent as compared to Takayasu's arteritis and inflammatory aneurysm. Elastic fibres were not severely destroyed. Endothelial cells (ECs) of most vasa vasorum expressed HLA-DR. The number of vasa vasorum around which inflammatory infiltrating cells were observed in vasculo-Behçet disease was significantly greater than in inflammatory aneurysms and Takayasu's arteritis (P < 0.001). The cytokines IL-1alpha, TNF-beta and IFN-gamma were expressed in neutrophils and lymphocytes which were distributed around vasa vasorum, as well as neutrophils adherent to HLA-DR positive ECs. CONCLUSION: Our results suggest that vasculo-Behçet disease should be classified as a neutrophilic vasculitis targeting the vasa vasorum. Aneurysm formation may be related to degeneration of arterial wall caused by inflammation of the vasa vasorum.

Adolescent↗

PubMedDate not supplied

Endothelial transport of anionized and cationized ferritin in the rabbit thoracic aorta and vasa vasorum.

Transport of anionized ferritins (AF,pl = 3.8-4.2), weakly cationized ferritins (WCF, pI = 7.8-8.1) and cationized ferritins (CF, pI greater than 9.0) was investigated in the rabbit aorta and vasa vasorum. After a 2-minute in situ perfusion, all ferritin species entered luminal vesicles and bound to the luminal endothelial membrane with a high surface density at vesicle necks and regions of cell overlap. In comparison to the aorta, the vasa vasorum had a higher surface density for AF, lower surface densities for CF and WCF, and fewer vesicles containing CF, WCF, or AF. In both types of vessels, vesicle loading of all ferritin species did not agree with a Poisson distribution. After perfusion times of up to 30 minutes, no abluminal vesicles or vasa vasorum endothelium contained CF or WCF; a few abluminal vesicles near cell borders contained AF. In the vasa vasorum, CF and AF entered the subendothelium via occasional fenestrae; AF, but not CF, also permeated the adventitia. Our findings indicate that: 1) binding sites for oppositely charged particles coexist in the same microdomains; 2) the glycocalyces of the vasa vasorum and aorta differ in their relative affinities for oppositely charged particles; 3) vesicular labeling with ferritin is not solely diffusive; and 4) vesicles do not traverse the aortic endothelium under these experimental conditions.

Animals↗