Bianchi Giampaolo, Marzocchi Rebecca, Agostini Federica, Marchesini Giulio
Department of Internal Medicine, 'Alma Mater Studiorum' University of Bologna, Italy.
Curr Opin Gastroenterol. 2005 Mar;21(2):197-200. doi: 10.1097/01.mog.0000153353.45738.bf.
Branched-chain amino acids (BCAAs) have a peculiar role in whole-body nitrogen metabolism. BCAAs are a substrate for protein synthesis, and have been used to conserve or restore muscle mass in advanced liver disease. In addition, the competitive action of BCAAs on amino acid transport across the blood-brain barrier may improve hepatic encephalopathy.
The effects of branched-chain amino acids on nutrition and ultimately on prognosis of patients with advanced cirrhosis have been confirmed in a large multicenter, long-term trial. Similarly, BCAA treatment improved the prognosis of patients with hepatocellular carcinoma, treated by chemoembolization. The mechanism for the beneficial effects of BCAA is likely to depend on the stimulating activity of BCAA on hepatocyte growth factor, favoring liver regeneration.
After an experience of 25 years with branched-chain amino acids, new data supports their beneficial effect in liver diseases. Although the number of patients who cannot tolerate dietary proteins in amounts sufficient to meet their increased catabolism is probably low, in this specific setting BCAAs remain the sole treatment of proved efficacy.
支链氨基酸（BCAAs）在全身氮代谢中具有特殊作用。BCAAs是蛋白质合成的底物，已被用于在晚期肝病中维持或恢复肌肉质量。此外，BCAAs对氨基酸跨血脑屏障转运的竞争作用可能改善肝性脑病。
在一项大型多中心长期试验中，已证实支链氨基酸对晚期肝硬化患者营养状况及最终预后的影响。同样，BCAA治疗改善了经化疗栓塞治疗的肝细胞癌患者的预后。BCAA有益作用的机制可能取决于其对肝细胞生长因子的刺激活性，有利于肝脏再生。
在使用支链氨基酸25年的经验之后，新数据支持它们在肝病中的有益作用。尽管无法耐受足够量膳食蛋白质以满足其增加的分解代谢的患者数量可能很少，但在这种特定情况下，BCAAs仍然是唯一经证实有效的治疗方法。
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