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Published on: January 14, 2014
Connective tissue analysis of the canine circle of Willis in hypertension
R J Bagshaw1, S J Barrer, R H Cox
1Department of Anesthesiology, University of Pennsylvania School of Medicine, Philadelphia.
Insights
The middle cerebral artery has more collagen than other canine circle of Willis vessels. Hypertension did not alter vessel composition, but increased total connective tissue in cerebral arteries.
Area of Science:
- Cardiovascular Science
- Cerebrovascular Research
- Connective Tissue Biology
Background:
- The circle of Willis is crucial for cerebral blood flow regulation.
- Understanding arterial wall composition is key to cerebrovascular health.
- Investigating the impact of hypertension on intracranial arteries is vital.
Purpose of the Study:
- To quantify collagen and elastin in canine circle of Willis arteries.
- To assess passive mechanical properties and their relation to connective tissue.
- To compare arterial composition in normotensive versus hypertensive states.
Main Methods:
- Determined collagen and elastin content in major canine circle of Willis arteries.
- Utilized seven normotensive and seven experimentally hypertensive dogs.
- Analyzed connective tissue composition and collagen-to-elastin ratios.
Main Results:
- Middle cerebral artery showed higher collagen content in normotensive dogs.
- Arterial site did not significantly affect elastin or total connective tissue in normotensive dogs.
- Hypertension did not significantly alter collagen, elastin, or collagen-to-elastin ratios in any cerebral artery.
Conclusions:
- Cerebral arteries exhibit site-specific connective tissue differences.
- Short-term hypertension increases total connective tissue in cerebral vessels.
- These findings may offer insights into cerebrovascular disease development.
Abstract:
The collagen and elastin contents of the major arterial components of the canine circle of Willis (basilar artery, posterior cerebral artery, internal carotid artery, middle cerebral artery, and anterior cerebral artery) were determined as measures of the passive mechanical properties of these vessels. Studies were carried out in seven normotensive dogs and seven dogs in which experimental renal hypertension of 3 months duration had been induced. In the normotensive animals, the collagen content of the middle cerebral artery exceeded that of the other vessels considered. The elastin content and the total connective tissue were not significantly affected by arterial site. The middle cerebral artery collagen to elastin ratio was greater than corresponding values for the basilar, posterior cerebral, and internal carotid arteries. Connective tissue differences were less pronounced in the hypertensive animals. No component of the canine circle of Willis in the hypertensive dogs showed a significantly different collagen content, elastin content, total connective tissue content, or collagen to elastin ratio. In comparing cerebral vessels from normotensive and hypertensive dogs, total connective tissue values were greater in hypertension for all arterial sites considered. These acute physiological changes in connective tissue content over small distances in intracranial blood vessels from normotensive animals, together with unique connective tissue responses of these vessels to short term hypertension, may suggest additional possible factors important in the natural history of cerebrovascular pathological conditions.
