Burma Oktay, Ozcan Mete, Kacar Emine, Uysal Ayhan, Şahna Engin, Ayar Ahmet
Department of Cardiovascular Surgery, Faculty of Medicine, Firat University, Elazig, Turkey.
Department of Biophysics, Faculty of Medicine, Firat University, Elazig, Turkey.
Cardiovasc J Afr. 2015 Jan-Feb;26(1):4-7. doi: 10.5830/CVJA-2014-041. Epub 2014 Dec 11.
The biological and pharmacological properties of vessels used in coronary artery bypass graft (CABG) surgery are as important as their mechanical properties. The aim of this study was to investigate the possible role of protein kinase C (PKC)-dependent mechanisms in leptin-induced relaxation in the human internal mammary artery (IMA).
IMA rings, obtained from patients undergoing CABG surgery, were suspended in isolated tissue baths containing Krebs-Henseleit solution, which were continuously gassed with 95% O2 and 5% CO2 at 37(°)C.
The IMA rings were pre-contracted with increasing concentrations of norepinephrine (NE 10(-9)-10(-4) mol/l) and the relaxation responses to sodium nitroprusside (SNP), a nitrosovasodilator, and leptin were studied in the presence and absence of a PKC inhibitor. Leptin (1 µM) caused a dose-dependent relaxation in NE pre-contracted IMA rings. Pre-treatment with a PKC inhibitor significantly attenuated this vasorelaxatory response to leptin in human isolated IMA.
It was found that SNP and leptin caused significant relaxation of the NE pre-contracted human IMA rings, and PKC was probably the sub-cellular mediator for this effect. Our findings may have clinical or pharmacological importance as it could be hypothesised that obese subjects who have a left IMA bypass graft would have better myocardial perfusion.
冠状动脉旁路移植术（CABG）中所使用血管的生物学和药理学特性与其机械特性同样重要。本研究的目的是探讨蛋白激酶C（PKC）依赖性机制在瘦素诱导的人乳内动脉（IMA）舒张中的可能作用。
从接受CABG手术的患者获取IMA环，将其悬挂于含有Krebs-Henseleit溶液的离体组织浴中，在37℃下持续用95% O₂和5% CO₂通气。
用递增浓度的去甲肾上腺素（NE 10⁻⁹ - 10⁻⁴ mol/l）对IMA环进行预收缩，然后在有和没有PKC抑制剂的情况下研究其对亚硝基血管舒张剂硝普钠（SNP）和瘦素的舒张反应。瘦素（1 μM）在NE预收缩的IMA环中引起剂量依赖性舒张。用PKC抑制剂预处理可显著减弱人离体IMA对瘦素的这种血管舒张反应。
发现SNP和瘦素可使NE预收缩的人IMA环显著舒张，PKC可能是这种效应的亚细胞介质。我们的发现可能具有临床或药理学重要性，因为可以推测接受左IMA旁路移植术的肥胖受试者可能有更好的心肌灌注。
