Study of the elastic skeleton of intracranial arteries in animal and human vessels by scanning electron microscopy.

Yamazoe, Naohiro; Hashimoto, Nobuo; Kikuchi, Hiroe; Kang, Youngeun; Nakatani, Hideyuki; Hazama, Fumitada

doi:10.1161/01.str.21.5.765

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…Although the nature and significance of the folds are still unclear, their site and size indicate that they are located between endothelial cells. 5 The area of loss of the folds corresponds to the area of degeneration of endothelial cells in the early stage of aneurysmal formation 8 and appears to correspond to the degenerative change of endothelial cells. Medial sponge-like structures are also located between smooth muscle cells and are destroyed during the course of degeneration of these cells.…”

Section: Discussionmentioning

confidence: 99%

“…- 4 The results of our previous study of normal cerebral arteries under scanning electron microscopy after hot formic acid extraction 5 showed that the internal elastic lamina was not the sole element, but a part of the complicated architecture of the elastic skeleton. Based on these observations, we considered that the process of various vascular pathologies might be re-evaluated by analyzing morphologic changes of the elastic skeleton in cerebral arteries.…”

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confidence: 99%

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Elastic skeleton of intracranial cerebral aneurysms in rats.

Yamazoe

Hashimoto

Kikuchi

et al. 1990

Stroke

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In an attempt to clarify the developmental mechanism of cerebral aneurysms, we studied the elastic skeleton of experimentally induced cerebral aneurysms in rats under scanning electron microscopy after hot formic acid extraction followed by freeze-drying. We produced cerebral aneurysms in 19 rats by unilaterally ligating the common carotid artery, inducing renal hypertension, and feeding /3-aminopropionitrile fumarate. The first noted change was the loss of folds protruding from the internal elastic lamina. Morphologic changes of the internal elastic lamina, considered to be primarily responsible for aneurysmal formation, occurred after the loss or disintegration of the elastic skeleton of first the intima, then the media. In large aneurysms with thick domes, we found proliferation of elastic lamellae that may reduce the risk of rupture. It seems probable that the complex elastic skeleton of the arterial wall may account for the mechanical properties of the artery and that growth of an aneurysm occurs due to disintegration of the elastic skeleton and not simply to rupture of the internal elastic lamina. We believe that such changes in the elastic skeleton are a property of the functional state of the cells that produce elastin. {Stroke 1990;21:1722-1726)A lthough the pathogenesis of cerebral aneu-/ \ rysms is still a matter of debate, many inves-. Z \ . tigators have considered degenerative changes of the internal elastic lamina, including the enlargement of fenestrations, to be responsible for the development of aneurysms. 1 - 4 The results of our previous study of normal cerebral arteries under scanning electron microscopy after hot formic acid extraction 5 showed that the internal elastic lamina was not the sole element, but a part of the complicated architecture of the elastic skeleton. Based on these observations, we considered that the process of various vascular pathologies might be re-evaluated by analyzing morphologic changes of the elastic skeleton in cerebral arteries. Our current study was designed to clarify changes of the elastic skeleton at various stages of aneurysmal formation using experimentally induced cerebral aneurysms. Materials and MethodsTo produce cerebral aneurysms, in 19 male SpragueDawley rats aged 8 weeks and weighing 250-300 g we Received January 29, 1990; accepted August 17, 1990. ligated the left common carotid artery and posterior branches of both renal arteries under anesthesia with 40 mg/kg i.p. sodium pentobarbital. One week after surgery 1% saline was substituted for the drinking water, and 2 weeks after surgery, the rats were fed a diet containing 0.12% j3-aminopropionitrile fumarate (Tokyo Kasei Co., Tokyo, Japan). We used 12 agematched rats as controls. Four to 16 weeks after surgery, the rats were perfused with heparinized 0.1 M phosphate buffer (pH 7.4) from the descending aorta, followed by fixation with 3 % glutaraldehyde in the same buffer. After perfusion and fixation, the major arteries at the base of the brain were carefully freed under a microscope and immers...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Elastic skeleton of intracranial cerebral aneurysms in rats.

Yamazoe

Hashimoto

Kikuchi

et al. 1990

Stroke

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“…The ECM is a dynamic network of proteins and proteoglycans that is essential for structural maintenance in many tissues and relies on a balance between synthesis and degradation of ECM proteins. The content and three-dimensional organization of elastin fibers, an essential component of the ECM of vessel walls, was found to be altered in the wall of cerebral aneurysms [6]. In a gene expression analysis of a single IA, elastin was among the most abundantly expressed tags, indicating that in this IA significant tissue remodeling was taking place [7].…”

Section: Introductionmentioning

confidence: 99%

Extended Single Nucleotide Polymorphism and Haplotype Analysis of the <i>elastin</i> Gene in Caucasians with Intracranial Aneurysms Provides Evidence for Racially/Ethnically Based Differences

König¹,

Ziegler²,

Schackert³

et al. 2004

Cerebrovasc Dis

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Background: There is growing evidence that genetic variants have an impact on the pathogenesis of intracranial aneurysm (IA). Recently, the genetic locus around the elastin gene (7q11) has been identified as linked to IA in a Japanese population. Our aim was to confirm these results in Caucasian populations. Methods: We conducted a case-control study in 120 Caucasian patients with IA and 172 controls to investigate 8 single nucleotide polymorphisms (SNPs) and various haplotypes within the elastin gene, which were frequently found and associated with the phenotype in the Japanese populations. Real-time PCR and melting curve analysis were used for the detection of genotypes. Results: Allele frequencies and genotypes were equally distributed between Caucasian cases and controls. We failed to identify haplotypes that are associated with the phenotype in our population, which is in contrast to the Japanese study. However, allele frequencies in control populations differ between Caucasians and Japanese. Conclusions: We found no association between SNPs and haplotypes of the elastin gene and the occurrence of IA in our Caucasian populations. However, our data provide strong evidence for racial/ethnic differences in the association of SNP and specific haplotypes of the elastin gene with the phenotype. There might be other genetic variants of the elastin gene associated with IA in Caucasians.

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“…In the present article, the term "subendothelial" refers to the region just below the endothelial surface but on the adluminal side of the IEL. Similarly, in the intracranial arteries of the rat and human, the IEL consists of a double layer, in this case associated with a honeycomb-like network of fine elastic fibers (48). IEL splitting and axially aligned fibrils have also been noted in pathological states, such as the formation of intimal pads or cushions and hypertension (39,44).…”

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Structural inhomogeneity and fiber orientation in the inner arterial media

Timmins

Yeh

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

109

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The microstructural orientation of vascular wall constituents is of interest to scientists and clinicians because alterations in their native states are associated with various cardiovascular diseases. In the arterial media, the orientation of these constituents is often described as circumferential. However, it has been noted that, just below the endothelial surface, the vascular wall constituents are oriented axially. To further study this reported change in orientation, and to resolve previous observations (which were made under conditions of no load), we used nonlinear optical microscopy to examine the orientation of collagen and elastin fibers in the inner medial region of bovine common carotid arteries. Images were obtained from this part of the arterial wall under varying degrees of mechanical strain: 0%, 10% axial, 10% circumferential, and 10% biaxial. We observed that close to the endothelium these components are aligned in the axial direction but abruptly change to a circumferential alignment at a depth of approximately 20 mum from the endothelial surface. The application of mechanical strain resulted in a significantly greater degree of fiber alignment, both collagen and elastin, in the strain direction, regardless of their initial unloaded orientation. Furthermore, variations in strain conditions resulted in an increase or a decrease in the overall degree of fiber alignment in the subendothelial layer depending on the direction of the applied strain. This high-resolution investigation adds more detail to existing descriptions of complex structure-function relationships in vascular tissue, which is essential for a better understanding of the pathophysiological processes resulting from injury, disease progression, and interventional therapies.

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Study of the elastic skeleton of intracranial arteries in animal and human vessels by scanning electron microscopy.

Cited by 11 publications

References 22 publications

Elastic skeleton of intracranial cerebral aneurysms in rats.

Elastic skeleton of intracranial cerebral aneurysms in rats.

Extended Single Nucleotide Polymorphism and Haplotype Analysis of the <i>elastin</i> Gene in Caucasians with Intracranial Aneurysms Provides Evidence for Racially/Ethnically Based Differences

Structural inhomogeneity and fiber orientation in the inner arterial media

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