Freund H, Hoover H C, Atamian S, Fischer J E
Ann Surg. 1979 Jul;190(1):18-23. doi: 10.1097/00000658-197907000-00004.
Postinjury metabolism is characterized by breakdown of muscle protein as substrate for energy production and gluconeogenesis and by the resultant loss of lean body mass and weight loss. The branched chain amino acids (BCAAs) which are principally oxidized by the skeletal muscle have been implicated in recent in vitro and in vivo studies as having special anticatabolic and regulating effects in skeletal muscle. We studied the anticatabolic effects of the BCAAs in 35 patients undergoing operative injury of moderate severity. In a prospective randomized and blinded manner patients were infused for five days starting immediately after surgery with either 5% dextrose or 5% dextrose with an amino acid solution containing 22, 35 or 100% BCAAs. All patients survived and there were no major postoperative complications. Mean hospital stay was 17 days for patients receiving amino acids and 19 days for patients receiving 5% dextrose only (p = ns). All three groups receiving amino acid solutions were in nitrogen equilibrium or in a slight positive nitrogen balance, while the group receiving 5% dextrose only was in a mean negative nitrogen balance of 6.6 +/- 0.6 gN/day. The differences between the three groups receiving amino acids were slight and not significant. Weight loss was 2 +/- 0.7 kg in the 5% dextrose group, 1 +/- 0.7 kg in the 22% BCAAs group, 0.5 +/- 0.5 kg in the 35% BCAAs group and the 100% BCAAs group gained 0.4 +/- 1.8 kg. Blood chemistries in the different groups and during the study period remained within normal limits except for ammonia levels rising significantly in the 5% dextrose group and SGOT levels rising in the 22% and 35% BCAA groups. With mild variations the plasma amino acid patterns in all groups were similar to the normal pattern, even in the 100% BCAAs group receiving an unbalanced amino acid solution, suggesting the complete cessation of amino acid efflux from muscle, the muscle depending solely on the exogenous supply of BCAAs to satisfy its metabolic requirements. The results suggest that early nutritional suppport in the postoperative period will result in nitrogen equilibrium and that the infusion of the three BCAAs only in the postoperative state is as effective in preventing muscle catabolism as other more balanced amino acid solutions. In the postinjury state balanced amino acid solutions rich in BCAA may prove beneficial.
损伤后代谢的特征是肌肉蛋白分解作为能量产生和糖异生的底物，以及随之而来的瘦体重丧失和体重减轻。主要由骨骼肌氧化的支链氨基酸（BCAAs）在最近的体外和体内研究中被认为对骨骼肌具有特殊的抗分解代谢和调节作用。我们研究了BCAAs对35例中度手术损伤患者的抗分解代谢作用。以前瞻性随机和盲法的方式，患者在手术后立即开始接受为期五天的输注，输注的溶液要么是5%葡萄糖，要么是含有22%、35%或100%BCAAs的氨基酸溶液与5%葡萄糖的混合液。所有患者均存活，且无重大术后并发症。接受氨基酸的患者平均住院时间为17天，仅接受5%葡萄糖的患者平均住院时间为19天（p=无显著差异）。接受氨基酸溶液的所有三组患者均处于氮平衡或轻微正氮平衡状态，而仅接受5%葡萄糖的组平均负氮平衡为6.6±0.6gN/天。接受氨基酸的三组之间的差异很小且无统计学意义。5%葡萄糖组体重减轻2±0.7kg，22%BCAAs组体重减轻1±0.7kg，35%BCAAs组体重减轻0.5±0.5kg，100%BCAAs组体重增加0.4±1.8kg。除5%葡萄糖组氨水平显著升高以及22%和35%BCAA组谷草转氨酶水平升高外，不同组和研究期间的血液化学指标均保持在正常范围内。尽管存在轻微差异，但所有组的血浆氨基酸模式均与正常模式相似，即使在接受不平衡氨基酸溶液的100%BCAAs组中也是如此，这表明肌肉中氨基酸外流完全停止，肌肉仅依赖于BCAAs的外源性供应来满足其代谢需求。结果表明，术后早期营养支持将导致氮平衡，并且仅在术后状态输注三种BCAAs在预防肌肉分解代谢方面与其他更平衡的氨基酸溶液一样有效。在损伤后状态，富含BCAA的平衡氨基酸溶液可能被证明是有益的。
