Risk factors of atherosclerosis and saphenous vein endothelial function.
BACKGROUND
Impaired vasomotor function has been suggested as playing a role in the pathophysiology of atherosclerosis and it may also affect the late patency of bypass grafts. We evaluated, in vitro, the influence of risk factors of atherosclerosis on saphenous vein endothelial function in patients with cardiovascular diseases.


METHODS
Forty-five saphenous vein rings with intact (E+) and denuded endothelium (E-) were studied. The following drugs were used: norepinephrine (NE), acetylcholine (Ach), histamine (H) and serotonine (5-HT).


RESULTS
Contraction to norepinephrine (n=15) showed a maximal tension of 783+/-115 percent that was increased in diabetics, smokers, and patients with hypertension. There was a wide range of response to acetylcholine in rings with intact endothelium (n=25), (mean relaxation 16.4+/-1.7 percent, ranging from -22.2 percent to 45 percent) with relaxation (26+/-1.1 percent) and contraction (-11+/-1.2 percent); relaxation was reduced in patients with hypertension and in diabetics (7.4+/-2.6 percent vs non diabetics 24.4+/-1.73 percent; p<0.01). Five of the 12 veins from diabetics exibited contraction (10+/-1.48 percent). Histamine (n=15) caused moderate relaxation at low doses (25+/-2.46 percent) followed by contraction at higher concentrations (184+/-5.7 percent). This was greater in diabetics (193+/-6.8 percent vs non diabetics 157+/-5.3 percent; p=0.045) while in preparations without endothelium (n=10) only relaxation was obtained (45+/-2.89 percent). Contraction (242+/-7.4 percent) was observed in response to serotonine (n=15) that was not affected by endothelial removal. In this study saphenous vein: (1) exhibited a wide range of responses to acetylcholine; (2) evoked marked contraction to norepinephrine and serotonine; (3) elicited contraction in response to histamine that was endothelium-dependent, suggesting the production or the release of an endothelium-derived-contracting-factor (EDCF).


CONCLUSIONS
Saphenous vein is able to secrete a contracting factor in patients with risk factors of atherosclerosis and above all diabetes. The mechanisms that regulate the balance between the relaxing and contracting factors and how the endothelial cells become the source of the substances with vasoconstrictor activity remain to be determined.
Sessa
C
C
Department of Vascular Surgery, Wayne State University, Detroit, USA.
Morasch
M D
MD
Friedland
M
M
Kline
R A
RA
D000109:Acetylcholine / Q000494:pharmacology; D001161:Arteriosclerosis / Q000150:complications / Q000503:physiopathology*; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D007537:Isometric Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011237:Predictive Value of Tests; D012307:Risk Factors; D012501:Saphenous Vein / Q000187:drug effects / Q000502:physiology*; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000494:pharmacology; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D016166:Free Radical Scavengers; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D012701:Serotonin; D006632:Histamine; D000109:Acetylcholine; D009638:Norepinephrine