Abstract

ECHEVERRI, Darío et al. in vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery. Biomédica [online]. 2008, vol.28, n.2, pp.298-304. ISSN 0120-4157.

Introduction. The vasodilator effect of caffeine in animal models arteries has been demostrated previously. However, studies with the same methodology using human arteries in vitro have not been performed. Objectives. The in vitro vasoactive effects of caffeine was evaluated on human internal mammary arteries. Materials and methods. Internal mammary artery rings were used (n=20). Endothelial function was evaluated with acetylcholine at a concentration of 3.16x10 ^-6 M, nitroglycerine at cumulative concentrations of 10 ^-11 M to 10 ^-4 M and caffeine with cumulative concentrations of 10 ^-8 M to 10 ^-4 M. Results. Nitroglycerin produced a maximum relaxation percentage of 87.4±12.3%, caffeine a percentage of 86.9±21.0% in arteries with functional endothelium, and of 71.6±28.6% in arteries with endothelial dysfunction. No differences were detected among the three groups ( p=0.289). Similarly, no differences were found between EC 50 in arteries with functional endothelium (1.66x10 ^-5 ±1.57x10 ^-5 M) and dysfunctional arteries (7.8 x10 ^-5 ±14.6 x10 ^-5 M). Nitroglycerine proved more potent than caffeine (EC 50 = 4.3 x10 ^-9 ±4.4x10 ^-9 M) ( p=0.013). Conclusions. Although nitroglycerin was a more potent vasodilator, caffeine had a strong arterial vasodilator effect regardless of endothelial function in human arteries.

Keywords : caffeine [therapeutic use]; myocardial revascularization; vasodilation; aorta; atherosclerosis; endothelium; acetylcholine.

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