Hatzakorzian Roupen, Shum-Tim Dominique, Wykes Linda, Hülshoff Ansgar, Bui Helen, Nitschmann Evan, Lattermann Ralph, Schricker Thomas
Department of Anaesthesia, McGill University Health Center, Montreal, Canada; Department of Critical Care, McGill University Health Center, Montreal, Canada;
Department of Cardiovascular Surgery, McGill University Health Center, Montreal, Canada;
J Appl Physiol (1985). 2014 Dec 1;117(11):1380-7. doi: 10.1152/japplphysiol.00175.2014. Epub 2014 Sep 25.
We investigated the effect of insulin administered as part of a hyperinsulinemic-normoglycemic clamp on protein metabolism after coronary artery bypass grafting (CABG) surgery. Eighteen patients were studied, with nine patients in the control group receiving standard metabolic care and nine patients receiving insulin (5 mU·kg(-1)·min(-1)). Whole body glucose production, protein breakdown, synthesis, and oxidation were determined using stable isotope tracer kinetics (l-[1-(13)C]leucine, [6,6-(2)H2]glucose) before and 6 h after the procedure. Plasma amino acids, cortisol, and lactate were also measured. Endogenous glucose production (preoperatively 10.0 ± 1.6, postoperatively 3.7 ± 2.5 μmol·kg(-1)·min(-1); P = 0.0001), protein breakdown (preoperatively 105.3 ± 9.8, postoperatively 85.2 ± 9.2 mmol·kg(-1)·h(-1); P = 0.0005) and synthesis (preoperatively 88.7 ± 8.7, postoperatively 72.4 ± 8.4 mmol·kg(-1)·h(-1); P = 0.0005) decreased in the presence of hyperinsulinemia, whereas both parameters remained unchanged in the control group. A positive correlation between endogenous glucose production and protein breakdown was observed in the insulin group (r(2) = 0.385). Whole body protein oxidation and balance decreased after surgery in patients receiving insulin without reaching statistical significance. In the insulin group the plasma concentrations of 13 of 20 essential and nonessential amino acids decreased to a significantly greater extent than in the control group. In summary, supraphysiological hyperinsulinemia, while maintaining normoglycemia, decreased whole body protein breakdown and synthesis in patients undergoing CABG surgery. However, net protein balance remained negative.
我们研究了作为高胰岛素-正常血糖钳夹术一部分给予的胰岛素对冠状动脉旁路移植术（CABG）后蛋白质代谢的影响。研究了18例患者，其中9例对照组患者接受标准代谢护理，9例患者接受胰岛素治疗（5 mU·kg⁻¹·min⁻¹）。在手术前和手术后6小时，使用稳定同位素示踪动力学（l-[1-(¹³)C]亮氨酸、[6,6-(²)H₂]葡萄糖）测定全身葡萄糖生成、蛋白质分解、合成和氧化。还测量了血浆氨基酸、皮质醇和乳酸。内源性葡萄糖生成（术前10.0±1.6，术后3.7±2.5 μmol·kg⁻¹·min⁻¹；P = 0.0001）、蛋白质分解（术前105.3±9.8，术后85.2±9.2 mmol·kg⁻¹·h⁻¹；P = 0.0005）和合成（术前88.7±8.7，术后72.4±8.4 mmol·kg⁻¹·h⁻¹；P = 0.0005）在高胰岛素血症情况下降低，而在对照组中这两个参数保持不变。在胰岛素组中观察到内源性葡萄糖生成与蛋白质分解之间存在正相关（r² = 0.385）。接受胰岛素治疗的患者术后全身蛋白质氧化和平衡降低，但未达到统计学意义。在胰岛素组中，20种必需和非必需氨基酸中的13种血浆浓度下降幅度明显大于对照组。总之，超生理高胰岛素血症在维持正常血糖的同时，降低了接受CABG手术患者的全身蛋白质分解和合成。然而，蛋白质净平衡仍为负。
