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Vasoconstrictor activity of coronary sinus plasma from patients with coronary artery disease
Insights
Plasma from the coronary sinus of patients with coronary artery disease causes vasoconstriction, potentially linked to serotonin release from platelets. This effect correlates with the severity of coronary artery narrowing.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
Background:
- Coronary artery disease (CAD) involves complex pathophysiological changes.
- Understanding the vasoactive properties of blood in CAD is crucial for therapeutic development.
Purpose of the Study:
- To investigate the vasoactive properties of plasma from different circulatory sources in patients with CAD.
- To identify potential mediators of vasoconstriction in the coronary sinus blood of CAD patients.
Main Methods:
- In vitro bioassay using isolated canine coronary artery rings.
- Measurement of tension changes in response to plasma samples from systemic arteries, superior vena cava, and coronary sinus.
- Assessment of plasma from patients with and without CAD, under rest and exercise conditions.
- Pharmacological blockade using a serotoninergic receptor antagonist.
Main Results:
- Coronary sinus plasma from CAD patients induced relaxation followed by constriction in arteries with endothelium, and only constriction in arteries without endothelium.
- Vasoconstrictor activity in coronary sinus plasma positively correlated with the severity and extent of coronary artery narrowing.
- Plasma from systemic circulation and coronary sinus plasma from non-CAD patients induced only endothelium-dependent relaxations.
- Methiothepin blocked the vasoconstriction, suggesting a role for serotonin (5-hydroxytryptamine).
Conclusions:
- Coronary sinus blood in patients with atheromatous CAD exhibits vasoconstrictor activity.
- This activity is likely mediated by platelet-released serotonin (5-hydroxytryptamine).
- The findings suggest a potential mechanism contributing to altered coronary blood flow in CAD.
Abstract:
Vasoactive properties of plasma samples taken from the coronary sinus, a systemic artery and the superior vena cava of 13 patients with angiographically proven coronary artery disease and from 5 patients with normal coronary arteriograms were assayed in vitro by measurement of the changes in tension of rings of isolated canine coronary arteries. Addition of 1 ml samples of platelet-rich plasma from the coronary sinus of patients with coronary artery disease into a 20 ml organ bath induced an initial relaxation followed by sustained constriction in bioassay coronary artery rings with endothelium and only vasoconstriction in rings without endothelium. The vasoconstrictor activity of the coronary sinus plasma showed positive correlation with the severity and extent of coronary artery narrowing. Systemic arterial and venous plasma samples from patients with coronary artery disease and the coronary sinus plasma from patients with no coronary artery disease evoked only endothelium-dependent relaxations. These vasoactive properties of the various plasma samples were similar whether the samples were taken during rest or during supine bicycle exercise. The serotoninergic receptor antagonist methiothepin prevented the vasoconstriction induced by the coronary sinus plasma samples. These data demonstrate that the coronary sinus blood of patients with atheromatous coronary artery disease exhibits vasoconstrictor activity that may be associated with 5-hydroxytryptamine (serotonin), presumably released from platelets.