Early morphology and pathology of the basilar artery remodeling induced by hemodynamic changes
0
Citation
0
Reference
20
Related Paper
Abstract:
Objective
To explore the basilar artery morphology and pathology after hemodynamic changes of basilar artery.
Methods
New Zealand white rabbits were subjected to bilateral common carotid artery ligation to produce compensatory vertebrobasilar artery flow increase. The basilar artery flow velocity was monitored by transcranial Doppler before the procedure and at 1 day, 1 week and 2 weeks after the procedure. DSA was performed at 1 week and 2 weeks after the procedure respectively and the basilar artery diameter and the extent of tortuosity were measured. The basilar artery tissues were harvested at 1 week and 2 weeks after the procedure and examined histologically by EVG and Masson staining.
Results
The basilar artery flow velocity of New Zealand white rabbit was increased significantly subjected to common carotid artery ligation (10.99 ml/min vs 36.53 ml/min, P<0.001). One or two weeks after surgery, the basilar artery diameter was expanded (0.60 mm vs 0.82 mm; 0.73 mm vs 1.03 mm, P<0.001), and the artery was curved. The internal elastic layer of artery was intact with smooth muscle cells proliferation in response to high flow and shear stress. The basilar artery was bent to the left side in 57.1% of all rabbits and there was significant difference compared with that of preoperation.
Conclusions
The hemodynamic increasing of the basilar artery after bilateral common carotid artery ligation of New Zealand white rabbits resulted in expansion and tortuosity of the basilar artery.
Key words:
Basilar artery; Hemodynamic; Vascular remodeling; AngiographyThe arterial blood supply of 40 carotid bodies in 20 Wistar rats of both sexes, aged 10-12 weeks (250-350 g), was examined by light microscopy. The carotid bodies of all rats were supplied by only one carotid body artery. The average diameter of the carotid body arteries was 40 microns. This artery arose either from the external carotid artery (97.5%) or the occipital artery (2.5%). There was an intimal cushion at the origin of the carotid body artery. The carotid body artery, after reaching the caudal pole of the carotid body, divided into the first-order branch. In the carotid body, the paranchyma was divided into the second-order branch. The carotid body artery was of the muscular type.
External carotid artery
Cite
Citations (7)
Flow-mediated dilatation has been described mainly in peripheral conduit arteries. The goal of this study was to examine mechanisms and functional implications of flow-mediated dilatation in large cerebral arteries in vivo. Vessel diameter and velocity of blood flow through the basilar artery were measured using a cranial window in 45 anesthetized rats. Mean blood flow velocity through the basilar artery increased by 94 +/- 8% during unilateral common carotid artery occlusion and 203 +/- 13% during bilateral occlusion. Diameter of the basilar artery increased by 10 +/- 1% during unilateral common carotid artery occlusion and 29 +/- 2% during bilateral occlusion from control diameter of 275 +/- 8 microns. Vasodilatation appeared with a delay of 13 +/- 1 seconds after the onset of the increase in flow velocity. With systemic arterial pressure maintained at baseline levels, pressure in the basilar artery (servonull) decreased initially during carotid occlusion, and during dilatation of the basilar artery, pr...
Cite
Citations (0)
Objective To observe the histopathological changes in the basilar artery after subarachnoid hemorrhage(SAH).Methods The model of SAH was established by twice injections of 0.3 ml autogenous arterial blood into the cistern magna in rats.Thei njection of 0.3 ml saline into the cistern magna was performed in control group.The luminal inner perimeter and wall thickness of the basilar arteries were measured and the ultrastructural change in the walls of the basilar arteries was observed in both the groups.Results The luminal inner perimeter of the basilar arteries were significantly shorter,and wall thickness was significantly thicker in SAH group than those in the control group(P0.01)3,5 and 7 days after SAH.The degenerations of endothelial cells internal elastic lamina which thickened and smooth muscle cells were observed in SAH group.The inner perimeter,wall thickness and wall ultrastructure of the basilar artery were normal in the control group.Conclusion The above-mentioned significant histopathological changes in the cerebral arteries produced by SAH in the rats is the basis of cerebral vasospasm after SAH.
Cisterna magna
Cistern
Internal elastic lamina
Cerebral Vasospasm
Cisterna
Cite
Citations (0)
Arteries that belong to the central nervous system (CNS) have thick and monotonous internal elastic lamina (IEL), Willis ring, and no collateral branch to the systemic circulation. These characteristics suggest that the circulation of the CNS is constant. In order to know how flow controls the arterial configuration of the CNS, flow of the vertebral and basilar arteries was increased experimentally using eight adult male Japanese white rabbits. Flow increase was induced by the simple ligation of the bilateral common carotid arteries (ligation group, n = 4) or by the ligation of the bilateral common carotid arteries at 1 week after arteriovenous fistula (AVF) between the left common carotid artery and the left external jugular vein (ligation plus AVF group, n = 4). Cineangiography revealed distinct flow increase in the ligation group at 5 weeks after ligation and in the ligation plus AVF group at 5 weeks after AVF (4 weeks after ligation). Vertebral and basilar arteries were remarkably dilated and elongated. Histopathologically, severe disruption of the IEL and focal thinning of the media were distinct. Endothelial cells were preserved and there was no inflammatory cell infiltration. These morphological features are consistent with increased flow-induced adaptive remodeling. It is suggested that the constancy of the flow may give the arterial tree of the CNS these morphological characterizations.
Collateral circulation
Circle of Willis
Cite
Citations (9)
Objective To use bilateral common carotid artery ligation for creating an aneurysm model of the basilar terminus in New Zealand white rabbits.Methods Twenty-six adult New Zealand white rabbits were subjected to sham operation or bilateral common carotid artery ligation to increase basilar artery flow.Basilar artery flow velocity was monitored by transcranial Doppler before the operation,and 1d,1week,and 4weeks after surgery.Cerebral angiography was performed 4weeks after surgery to observe the changes of basilar arteries.The basilar arteries were harvested to observe the morphological changes of the arteries and the histological characteristics of the bifurcation tissues 1week and 4weeks after the surgery.Results All animals survived in the sham group,and80%(16/20)of the animals survived in the experimental group.The basilar artery flow velocity increased sharply one day after operation(increased by 226%)in the experimental group,and it kept increasing 1week after the operation until reaching a stable state4weeks after operation.The basal arteries were dilated obviously and displayed tortuous formation after one week in the experimental group,but there was no such change in the sham group.All rabbits in the experimental group presented with thinned media and absent,disrupted or thinned internal elastic lamina near the basilar terminus.Conclusion Blood flow increase at the basilar bifurcation caused by ligation of the bilateral common carotid arteries can lead to aneurysmal change at the basilar terminus of New Zealand white rabbits.
Cite
Citations (0)
Collateral circulation
Cite
Citations (8)
Objective: This study investigates the change of endothelial cell morphology and function at the rabbit basilar bifurcations in response to sustained high blood flow after bilateral common carotid artery ligation.Methods: Fifteen adult female New Zealand white rabbits were divided into experimental and sham control groups.The experimental group was subjected to bilateral common carotid artery ligation to increase the compensatory basilar artery flow.Basilar artery flow was monitored by transcranial Doppler after surgery.The endothelial cells at the arterial bifurcations were studied morphologically by electron microscopy and immunohistochemistry using β-catenin antibodies.Basilar artery flow increased significantly following common carotid artery ligation.Results: Early-stage basilar artery bifurcation aneurysms were present in all rabbits at three months after ligation.The endothelial cells changed from a fusiform to column shape at the basilar artery bifurcation.Gaps between endothelial cells of the experimental group appeared wider in the electron microscopic photographs compared with those of the control group.The expression of endothelial βcatenin at the arterial bifurcations also decreased. Conclusion:This study is the first to present endothelial cell changes of basilar artery bifurcation in response to sustained high blood flow in rabbits.Endothelial cell impairment possibly initiates aneurysm formation.
Cite
Citations (11)
Our aim was to investigate the effects of ageing on the vascular contractility of carotid and basilar arteries from guinea-pigs, in a model of total stenosis. Moreover, we attempted to identify whether total stenosis of the left common carotid (stenosed) in adult guinea-pigs, would affect the contractions of contralateral carotid (intact) and basilar arteries to different vasoconstrictors. With this purpose, the left carotid was occluded with a silk thread at a position close to its origin. Vascular reactivity experiments using standard muscle bath were performed 7, 15, 30, and 90 days after carotid occlusion. Reactivity of carotid and basilar arteries to endothelin-1, phenylephrine and KCl was reduced with ageing in naive guinea-pigs. The endothelin-1 and KCl-induced contractions were unaltered in arteries from SHAM-operated animals. Moreover, phenylephrine-induced contractions were reduced in both carotids from 7 days SHAM-operated guinea-pigs, when compared to naive group. Stenosis induced progressive reduction in the contraction induced by endothelin-1, phenylephrine and KCl in the stenosed carotid, when compared to their respective age-matched naive and SHAM groups. Interestingly, an increased contractile-response to vasoconstrictor agents in all the contralateral carotids was observed. Stenosis (30 and 90 days) also induced an increase in the contractions induced by endothelin-1 in the basilar artery. Conversely, phenylephrine and KCl-induced contractions were reduced in basilar arteries 7, 15, 30 and 90 days after stenosis. These results showed that stenosis in adult guinea-pigs induce alterations of vascular reactivity in arteries distant from the site of injury. Thus, in spite of the common use of contralateral carotid as control, it must be aware of the potential alteration induced by stenosis in the vascular motility of such vessels. Additionally, it was verified a relationship between the period of stenosis and the alterations in the vascular reactivity to these vasoconstrictors.
Phenylephrine
Cite
Citations (3)
Phenylephrine
Cite
Citations (3)
Objective To develop a rabbit model of unilateral common carotid artery atherosclerotic occlusion by high-fat diet and Ameroid ring insertion in their common carotid artery to make hemodynamic changes in extracranial carotid artery and corresponding changes of microvessel and ultrastructure in brain tissues. Methods Twenty male New Zealand White rebbits were randomly assigned into two groups (10 each). The rabbits in group Ⅰ were normally fed and those in group Ⅱ were fed with high-fat diet. Ameroid rings were placed in the right common carotid artery (RCCA) of 6 rabbits in group Ⅱ (group Ⅱa) 4 weeks after high-fat diet,and intima-media thickness (IMT) and hemodynamic parameters of the both groups were detected by Duplex Ultrasound at the 1st,2nd,3rd and 4th weekend after rings insertion. At the 4th weekend after the operation,the brain tissue was examined by histopathological analyses. Results No significant differences existed in group Ⅰ in every index. The blood flow beam in RCCA of group Ⅱa tapered and blood flow velocity increased after operation. The blood flow velocity reduced in the 4th week and then disappeared at the weekend. At the 4th weekend microscopy revealed that new hyperplastic microvessels were more in group Ⅱa than in group I. The microvessels on the right side were more than those on the left side in group Ⅱa. Under a transmission electron microscope,the ultrastructure of brain tissues in group Ⅱa appeared ischemic and hypoxic pathological changes. Conclusions A new rabbit model of unilateral common carotid artery atherosclerotic occlusion has been established,with which the pathophysiological process of ischemic cerebrovascular disease has been discussed by associating the changes of extracranial carotid artery hemodynamics with the changes of brain tissue ultrastructure. This model is useful to investigate the pathophysiology and treatment of extracranial carotid artery stenosis and occlusive diseases.
External carotid artery
Microvessel
Cite
Citations (0)