Millikan W J, Henderson J M, Warren W D, Riepe S P, Kutner M H, Wright-Bacon L, Epstein C, Parks R B
Ann Surg. 1983 Mar;197(3):294-304. doi: 10.1097/00000658-198303000-00009.
It has been proposed that hepatic encephalopathy and malnutrition in cirrhosis can be reversed by infusion of a protein formula (F080) enriched with branched-chain amino acids (valine, leucine, isoleucine) and containing decreased amounts of aromatic amino acids (phenylalanine, tyrosine, tryptophan). This hypothesis was tested by measuring changes in encephalopathy status, plasma ammonia, amino acid profile, and liver function during seven metabolic balance studies in three patients with cirrhosis and subclinical encephalopathy given increasing amounts (20-100 g/d) of F080. The results showed the following: 1) positive nitrogen balance was achieved only with 80 and 100 g F080/day; 2) plasma ammonia fell during negative, but increased during positive nitrogen balance; 3) plasma tyrosine and cystine fell significantly (p less than 0.05) with all intakes of F080; 4) the abnormal branched-chain to aromatic amino acid ratio was reversed; 5) extracellular volume was expanded in all patients; 6) albumin, bilirubin, prothrombin time became abnormal; and 7) encephalopathy did not significantly change from baseline. It is concluded that, in this population, F080 is an inadequate nutritional formula when given as the sole protein source because it produces hypotyrosinemia and hypocystinemia. The marked changes in the ratio of branched-chain to aromatic amino acids are not accompanied by improvement in encephalopathy.
有人提出,通过输注富含支链氨基酸(缬氨酸、亮氨酸、异亮氨酸)且芳香族氨基酸(苯丙氨酸、酪氨酸、色氨酸)含量降低的蛋白质配方(F080),可逆转肝硬化患者的肝性脑病和营养不良状况。在三项针对患有肝硬化和亚临床肝性脑病的患者进行的七项代谢平衡研究中,通过测量肝性脑病状态、血浆氨、氨基酸谱和肝功能的变化,对这一假设进行了验证。这三项研究中,患者摄入的F080量逐渐增加(20 - 100克/天)。结果显示如下:1)仅在每日摄入80克和100克F080时实现了正氮平衡;2)血浆氨在负氮平衡期间下降,但在正氮平衡期间上升;3)所有F080摄入量下,血浆酪氨酸和胱氨酸均显著下降(p小于0.05);4)异常的支链与芳香族氨基酸比例得到逆转;5)所有患者的细胞外液量均增加;6)白蛋白、胆红素、凝血酶原时间变得异常;7)肝性脑病与基线相比无显著变化。得出的结论是,在该人群中,当F080作为唯一蛋白质来源给予时,它是一种不充分的营养配方,因为它会导致低酪氨酸血症和低胱氨酸血症。支链与芳香族氨基酸比例发生的显著变化并未伴随肝性脑病的改善。