The prevalence of ischemic heart disease is lower in premenopausal females than in males of corresponding age. This could be related to gender differences in coronary functions. We tested whether biomechanical differences do really exist in the intramural coronary artery resistance between male and female rats. Intramural branches of the left anterior descending coronary artery [uniformly ∼200 μm in diameter] were isolated, canulated and studied by microarteriography. Intraluminal pressure was increased from 2 to 90 mmHg in stepwise and steady state diameters were measured. Measurements were repeated in the presence of vasoconstrictor U46619 [10-6 M] and vasodilator bradykinin [10-6 M]. In the end passive diameters were recorded in calcium free saline. A similar inner radius and a larger wall thickness [41.5±2.9 μm vs. 31.4±2.7 μm at 50 mmHg in the passive condition, p<0.05] resulted in lower tangential wall stresses in male rats [18.9±1.9 kPa vs. 24.9±2.5kPa at 50 mmHg, p<0.05]. The elastic modulus of vessels from male animals was significantly smaller at higher pressures. Vasoconstrictor response to U46619 was significantly stronger in male, than in female animals. Endothelial relaxations induced by bradykinin were not different in the two sexes. This is the first demonstration, that biomechanical characteristics of intramural coronary resistance arteries of a mammalian species are different in males and females. Larger wall thickness and higher vascular contractility in males are associated with similar endothelial function and a lesser high-pressure isobaric stiffness compared to females. These gender differences in biomechanics of coronary resistance arteries may contribute to a better understanding of pathological differences in humans.
|Number of pages||10|
|Journal||Magyar Noorvosok Lapja|
|Publication status||Published - Feb 14 2007|
ASJC Scopus subject areas
- Reproductive Medicine
- Obstetrics and Gynaecology