Sodha Neel R, Feng Jun, Clements Richard T, Bianchi Cesario, Boodhwani Munir, Ramlawi Basel, Mieno Shigetoshi, Khabbaz Kamal R, Sellke Frank W
Division of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass, USA.
Surgery. 2007 Aug;142(2):243-52. doi: 10.1016/j.surg.2007.03.010.
Cardioplegic arrest (CP) and cardiopulmonary bypass (CPB) can lead to dysfunction in the coronary and skeletal microcirculation leading to impaired tissue perfusion. alpha-Adrenergic signaling pathways acting on these microcirculatory beds are thought to involve protein kinase C (PKC). We investigate here the role of the conventional PKCs in microvascular function in the setting of CP/CPB.
Atrial and skeletal muscle was harvested from 30 patients undergoing cardiac surgery before and after CP/CPB. Microvessels were used for Western blotting and immunofluorescent staining against conventional PKCs. Microvascular constriction was assessed in pre- and post-CP/CPB samples in response to alpha-adrenergic stimulation with phenylephrine, with and without a PKC-alpha inhibitor or PKC-alpha activator. PKC activity was assessed in isolated microvessels.
Western blotting and immunostaining demonstrated only PKC-alpha in coronary and skeletal microvessels. CP/CPB diminished contractile responses to phenylephrine in coronary and skeletal samples. Inhibition of PKC-alpha reduced phenylephrine induced vasoconstriction in coronary and skeletal microvessels, whereas activation of PKC-alpha-augmented phenylephrine induced responses. PKC activity was decreased in coronary microvessels and to an even greater degree in skeletal microvessels after CP/CPB.
PKC-alpha is the predominant conventional PKC present in the human coronary and skeletal microcirculation. It likely plays a key role in alpha-adrenergic signaling in microvessels and in the vasomotor dysfunction after CP/CPB.
心脏停搏（CP）和体外循环（CPB）可导致冠状动脉和骨骼肌微循环功能障碍，进而导致组织灌注受损。作用于这些微循环床的α-肾上腺素能信号通路被认为涉及蛋白激酶C（PKC）。我们在此研究传统PKC在CP/CPB情况下微血管功能中的作用。
从30例接受心脏手术的患者在CP/CPB前后采集心房和骨骼肌。微血管用于针对传统PKC的蛋白质印迹和免疫荧光染色。在CP/CPB前后的样本中，使用苯肾上腺素进行α-肾上腺素能刺激，在有和没有PKC-α抑制剂或PKC-α激活剂的情况下，评估微血管收缩情况。在分离的微血管中评估PKC活性。
蛋白质印迹和免疫染色显示冠状动脉和骨骼肌微血管中仅存在PKC-α。CP/CPB减弱了冠状动脉和骨骼肌样本对苯肾上腺素的收缩反应。抑制PKC-α可降低苯肾上腺素诱导的冠状动脉和骨骼肌微血管收缩，而激活PKC-α可增强苯肾上腺素诱导的反应。CP/CPB后，冠状动脉微血管中的PKC活性降低，骨骼肌微血管中的PKC活性降低程度更大。
PKC-α是人类冠状动脉和骨骼肌微循环中存在的主要传统PKC。它可能在微血管的α-肾上腺素能信号传导以及CP/CPB后的血管舒缩功能障碍中起关键作用。
