Vasa vasorum in atherosclerotic coronary arteries: responses to vasoactive stimuli and regression of atherosclerosis
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J K Williams1, M L Armstrong, D D Heistad
1Department of Internal Medicine, Veterans Administration Medical Center, Iowa City, Iowa.
Insights
Vasa vasorum in atherosclerotic coronary arteries respond to vasoconstrictors. Atherosclerosis regression leads to vasa vasorum loss and reduced blood flow, not vessel constriction.
Area of Science:
- Cardiovascular Research
- Vascular Biology
- Atherosclerosis Research
Background:
- Vasa vasorum supply blood to the outer wall of large arteries.
- Their role in atherosclerosis and its regression is not fully understood.
Purpose of the Study:
- To investigate the response of vasa vasorum to vasoactive stimuli in atherosclerotic coronary arteries.
- To examine how atherosclerosis regression impacts blood flow through the vasa vasorum.
Main Methods:
- Studied three groups of monkeys: normal, atherosclerotic, and regression.
- Measured vasa vasorum blood flow using microspheres.
- Administered vasoactive stimuli like phenylephrine, serotonin, and adenosine.
Main Results:
- Blood flow to intima-media was significantly higher in atherosclerotic vs. normal monkeys.
- Phenylephrine and serotonin decreased vasa vasorum flow in atherosclerotic monkeys.
- Atherosclerosis regression resulted in a sixfold decrease in intima-media blood flow, primarily due to vessel loss rather than constriction.
Conclusions:
- Vasa vasorum in atherosclerotic coronary arteries are responsive to vasoconstrictor stimuli.
- Regression of atherosclerosis leads to a significant loss of vasa vasorum and reduced blood flow in the coronary intima-media.
Abstract:
The goals of this study were to determine whether vasa vasorum in atherosclerotic coronary arteries respond to vasoactive stimuli and to examine effects of regression of atherosclerosis on blood flow through vasa vasorum in coronary arteries. We studied three groups of monkeys: normal, atherosclerotic, and regression. Blood flow to vasa vasorum was measured with microspheres. Blood flow to intima-media (ml/min x 100 g) was 5 +/- 1 (mean +/- SEM) in normal and 47 +/- 7 in atherosclerotic monkeys (p less than 0.05). Infusion of phenylephrine or serotonin did not alter flow through vasa in normal monkeys. In atherosclerotic monkeys, phenylephrine decreased flow through vasa vasorum in intima-media of coronary arteries to 24 +/- 4 (p less than 0.05), and serotonin decreased flow to 27 +/- 5 (p less than 0.05). In regression monkeys, blood flow to intima-media was sixfold less (7 +/- 2 ml/min x 100 g) than in atherosclerotic monkeys (p less than 0.05). During infusion of adenosine, blood flow to vasa was fourfold greater in atherosclerotic monkeys than after regression of atherosclerosis. This finding suggests that loss of vessels, not constriction of existing vessels, accounts for the decrease in flow through vasa in intima-media after regression of atherosclerosis. We conclude that vasa vasorum in atherosclerotic coronary arteries respond to vasoconstrictor stimuli and that there is loss of vasa vasorum and a large decrease in blood flow through vasa to intima-media of coronary arteries after regression of atherosclerosis.