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Background and Aims: Obesity is a risk factor for endothelial dysfunction and atherosclerosis. However, perivascular adipose tissue can release adipokines and other unknown adipose-derived relaxing factors. Therefore, we investigated the impact of obesity on vascular function and expression of genes in perivascular adipose tissue from internal mammary arteries of patients with coronary artery disease undergoing coronary artery bypass grafting., Methods: The vessel function was compared between groups of patients with a body-mass index (BMI) between 25 and 30 kg/m 2 . The groups did not differ in age, gender (males), and ejection fraction. Vascular segments of internal mammary arteries were examined in a Mulvany myograph. Following preconstriction with noradrenaline, dose-response curves were assessed for relaxation with acetylcholine and sodium nitroprusside., Results: Maximum contraction in response to potassium and noradrenaline was increased in obese patients with a BMI >30 kg/m 2 . EC50 of endothelium-dependent relaxation was impaired in patients with a BMI above 25, but below 30 kg/m 2 . Sodium nitroprusside-mediated maximal relaxation was not different between study groups. Integrin alpha X chain (ITGAX/CD11c) and macrophage mannose receptor (MRC1/CD206) expression was reduced in perivascular adipose tissue of patients with a BMI above 30 kg/m 2 , while adiponectin (ADPQ) expression was increased in the same tissue., Conclusion: Our data suggest a partially reduced endothelial function in internal mammary arteries of adipose patients with a BMI between 25 and 30 kg/m 2 undergoing coronary artery bypass grafting surgery. Increased adiponectin expression in perivascular tissue might contribute to maintenance of endothelial function in obese patients with a BMI above 30 kg/m 2 ., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Estrogen modulates adrenergic reactivity of macrovessels, resulting in weaker α-adrenergic vasoconstriction in females than males. However, the mechanisms governing this important sex-specific difference are not well understood. We hypothesized that vessels of females express more dilatory β-adrenoceptors, which counteract constrictive effects of α-adrenoceptors. This hypothesis was tested using aortas of normotensive (WKY) and hypertensive rats (SHR), along with human mammary artery. Selective blockade of β 1 (CGP20712) or β 3 (SR59230A), but not β 2 (ICI118,551) adrenoceptors, greatly increased α-adrenergic constriction (norepinephrine) of aorta in female SHRs, but not in male SHRs at 12 weeks of age. Consistently, the selective β 1 /β 2 (isoproterenol) and β 3 -adrenergic (BRL37344) relaxation was stronger in female SHRs than in males. Removal of endothelium and use of L-NMMA abolished sex-difference in α-adrenergic constriction and β-adrenergic relaxation. Immunostainings revealed endothelial localization of β 1 - and β 3 -adrenoceptors. mRNA levels of aortic β 1 - and β 3 -, but not β 2 -adrenoceptors were markedly higher in female than in male SHRs. The sex-specific differences in α-adrenergic constriction and β-adrenoceptor mRNA levels were age-dependent, predominantly present up to 29 weeks and disappeared at 36 weeks of age. The sex-specific difference was not strain-dependent and was similarly present in normotensive WKY rats. Human mammary artery of women showed a weaker α-adrenergic constriction than arteries of men. This sex-specific difference was prominent at 45-65 years and disappeared with aging. Our results convincingly demonstrate that female macrovessels express more dilatory β 1 - and β 3 -adrenoreceptors than male vessels with a predominant endothelial localization. This sex-specific difference is functionally relevant in young adults and is attenuated with aging.