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PubMed2004

Adventitial vasa vasorum heterogeneity among different vascular beds.

INTRODUCTION: Different vascular beds show substantial variation in their susceptibilities for development of vascular disease like atherosclerosis, and thereby exhibit a variety of different clinical presentations. Yet, the underlying mechanism of this heterogeneity is not well defined. Recent evidence suggests a role for the vasa vasorum (VV) in vascular disease. We hypothesized that there is a differential distribution structure of adventitial VV in different vascular beds. Hence, the current study was designed to characterize and compare the structure of the adventitial VV in the coronary and the peripheral circulation. METHODS: Samples of vessels from different vascular beds were obtained from 6 female crossbred domestic pigs. The samples were scanned using micro-computed tomography, and the images reconstructed and analyzed to characterize VV architecture, including vessel wall area, VV count, VV density, intravessel spatial distribution, mean diameter of first- and second-order VVs and the ratio of second- to first-order VVs. RESULTS: There were significant differences in VV density among different vascular beds. Density was highest in coronary arteries (2.91 +/- 0.26 vessels/mm2, P <.05, vs renal, carotid, and femoral arteries), intermediate in renal arteries (1.45+/- 0.22 vessels/mm2, P <.05, vs femoral artery) and carotid arteries (0.64 +/- 0.08 vessels/mm2, P <.05, vs femoral artery), and lowest in femoral arteries (0.23 +/- 0.05 vessels/mm2 ). A similar pattern for the ratio of second- to first-order VV was also observed. Random intravessel spatial distribution of VVs was seen in all vascular beds. CONCLUSION: The current study demonstrates a differential structure of the adventitial VV in different vascular beds. This intra- and intervessel heterogeneity in VV anatomy is a phenotypic variability that might determine a differential local response to systemic risk factors and, thereby, variable propensity for vascular disease among different vascular beds.

Animals↗
PubMed1985

Scanning electron microscopic studies of the vasa vasorum of thoracic aortas.

Using hot alkaline solution, the elastic laminae were extracted from aortas and observed with scanning electron microscopy. Vascular structures were found in the elastin layers of the tunica media in descending thoracic aortas of sheep, dogs, and pigs, and these tube-like structures were filled with elastomer which was injected through the heart of the animal in vivo. Sub-intimal microvessels were also found to be filled with the elastomer and it is concluded that vasa vasorum can exist close to the internal elastic lamina in these animals.

Animals↗
PubMed1989

Vein-to-artery grafts: the long-term development of neo-intimal hyperplasia and its relationship to vasa vasorum and sympathetic innervation.

A series of 14 vein-to-artery grafts, 1 mm in diameter and 5 mm long, were inserted microsurgically into iliac arteries of rats. They were analysed histologically 8-18 months later and compared with control iliac arteries in the same rats. Neo-intimal hyperplasia developed and was measured in all grafts but the values did not significantly exceed the equivalent intimal plus medial thicknesses of control arteries. Vasa vasorum developed and were quantitated as the number of vessels per mm2 of neo-intima, but also did not differ significantly from control values. The density of sympathetic innervation was quantitated using fluorescent catecholamines. There was an overall significant increase in the long-term graft innervation compared with control arteries. These results show that such small vein grafts adapt and function very effectively, in a manner remarkably similar to the artery they replace, for long periods of time.

Adrenergic Fibers↗
PubMed2006

Contrast ultrasound imaging of the carotid artery vasa vasorum and atherosclerotic plaque neovascularization.

Cardiovascular disease is associated with the aging of the population, obesity, metabolic syndrome, and diabetes. Therefore, it is important to develop non-invasive imaging systems to detect "at-risk" populations. New data suggest that contrast-enhanced ultrasound (CU) imaging of the carotid arteries enhances luminal irregularities (i.e., ulcers and plaques), improves near-wall, carotid intima-media thickness, and uniquely permits direct, real-time visualization of neovasculature of the atherosclerotic plaque and associated adventitial vasa vasorum. With continued clinical investigation, CU imaging of the carotid artery may afford an effective means to non-invasively identify atherosclerosis in "at-risk" populations while providing new standard for therapeutic monitoring.

Atherosclerosis↗
PubMed1993

Graft vascular disease in the great vessels and vasa vasorum.

To determine whether the great vessels were subject to transplantation-associated arteriosclerosis (graft vascular disease) we studied sections of aorta and pulmonary arteries from 19 cardiac explant cases. Sections of the same vessels from five autopsied hearts from patients who had received liver and/or kidney transplants with immunotherapy as well as from eight recipient hearts served as controls. In addition, eight donor hearts (three aortae and eight pulmonary arteries) that were not used for heart transplantation were examined. Intimal proliferation was noted in the aorta but affected the pulmonary arteries only slightly, whereas the vasa vasorum of both vessels were involved and were occluded or stenosed by thickened intima containing recanalized capillaries. On morphometric study the ratio of intima to media in the aorta was significantly higher in the heart transplant group than in the control group (0.14 +/- 0.14 [n = 19] v 0.02 +/- 0.02 [n = 16]; P < .01). This intimal thickening was not correlated with the use of cyclosporine or with other clinicopathologic factors. The cytomegalovirus infection rate was higher in the heart transplant group (85%) than in the control group (40%).

Adolescent↗
PubMed1999

Vasa vasorum: another cause of the carotid string sign.

BACKGROUND AND PURPOSE: Our purpose was to describe a variant of the carotid string sign that may be associated with a completely occluded vessel and to consider possible pathophysiological mechanisms for this observation. METHODS: Carotid angiography was performed in three patients with suspected carotid stenosis and in a fourth with carotid dissection. Surgery was performed in one of the patients with carotid stenosis. RESULTS: On all angiograms, instead of a single linear or curvilinear contrast "string," either single or multiple serpiginous channels were seen. In one case, such a channel was seen emanating from below the origin of an occluded internal carotid stump, reconstituting the distal portion of the vessel. Surgery revealed a completely occluded lumen with a small intramural vessel bypassing the obstruction. CONCLUSION: We propose that these channels are either atherosclerotically induced neovessels connecting bridging vasa vasorum or recanalized luminal thrombus. We review the literature associated with this subject.

Aged↗
PubMed1981

Vein to artery grafts. A quantitative study of revascularization by vasa vasorum and its relationship to intimal hyperplasia.

Iliolumbar vein to iliac artery grafts were placed in 40 rats by microsurgical technique. Groups of animals were perfused with fixative at eight intervals between one and 20 weeks after operation, and sections of the graft and control arteries (the opposite iliacs) were analyzed microscopically. The revascularization of the graft by capillaries commenced within the first postoperative week. The level of vascularity (capillaries per cross-sectional mm2) increased during the first four weeks, maintained a constant level and declined after week 16. The grafts of the 17--20 week group were substantially less vascular than the earlier groups. Intimal thickening commenced at three to four weeks after operation, i.e. during the period of increasing graft vascularity. The mean intimal proportion of the graft was 14% at four to five weeks and at 17--20 weeks was 35% of the cross-sectional area of the graft wall. However, the actual thickness of the intima did not increase significantly with time, rather the whole graft wall tended to become thinner. At 17--20 weeks grafts which showed a high degree of intimal thickening had significantly fewer capillaries within their walls. Quantitative evidence is presented to suggest that the continued growth of the graft intima may not be supported by a similar increase in the number of vasa vasorum. Therefore, it is suggested that the reduced level of vascularity in grafts with hyperplastic intimae may form an ischemic basis for degenerative changes which are known to take place in some long-term grafts.

Animals↗
PubMed2001

In utero remodeling of the fetal lamb ductus arteriosus: the role of antenatal indomethacin and avascular zone thickness on vasa vasorum proliferation, neointima formation, and cell death.

BACKGROUND: The ductus arteriosus (DA) of newborn infants exposed in utero to indomethacin is resistant to postnatal indomethacin; we hypothesized that this is due to ductus constriction in utero, with subsequent remodeling of the vessel. METHODS AND RESULTS: Infusion of fetal lambs with indomethacin for 48 hours constricted the DA and increased the thickness of the avascular zone of the DA, which in turn induced the expression of vascular endothelial growth factor, endothelial nitric oxide synthase (due to ingrowth of vasa vasorum), neointima formation, and loss of smooth muscle cells; moderate degrees of DA constriction in utero increased NO production, which inhibited DA contractility. Marked degrees of DA constriction decreased tissue distensibility and contractile capacity. CONCLUSIONS: DA patency is no longer controlled primarily by prostaglandins once it has been exposed to indomethacin in utero.

6-Ketoprostaglandin F1 alpha↗
PubMed1959

[Vasa vasorum].

Explore the source record for details and available documents.

Blood Vessels↗
PubMed2004

Vasa vasorum in plaque angiogenesis, metabolic syndrome, type 2 diabetes mellitus, and atheroscleropathy: a malignant transformation.

BACKGROUND: Vascularization is an exciting and complex mechanism involving angiogenesis and arteriogenesis. The metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) are associated with multiple metabolic toxicities, which result in reactive oxygen species (ROS) due to an elevated tension of oxidative-redox stress and an accelerated atherosclerosis termed atheroscleropathy. RESULTS: This atheroscleropathy is associated with accelerated angiogenesis within the vulnerable, thin-cap fibro-atheroma, prone to rupture resulting in acute coronary syndromes (ACS). The resulting intimopathy with its neovascularization due to angiogenesis of the adventitial vasa vasorum (Vv) is prone to intraplaque hemorrhage (IPH). These IPH are associated with destabilization of the vulnerable plaques resulting in plaque erosion and plaque rupture resulting in ACS. In atheroscleropathy the adventitial Vv invades the plaque in a malignant-like fashion and concurrently is associated with chronic inflammation, as macrophages are being deposited within the shoulder regions of these vulnerable plaques. These angiogenic Vv provide a custom delivery vascular network for multiple detrimental substrates, which further accelerates the growth of these vulnerable plaques and atheroscleropathy. There exists a vascularization paradox in MS and T2DM, in that, angiogenesis within the plaque is induced and arteriogenesis is impaired. CONCLUSION: This review will attempt to provide a database of knowledge regarding the vascularization process (angiogenesis and arteriogenesis) and its mechanisms to better understand the increased cardiovascular risk and the increased morbidity and mortality associated with MS and T2DM.

Journal Article↗