肝脏疾病病人的营养支持(4)
严重肝损时，血浆氨基酸谱发生变化，主要表现为支链氨基酸/芳香族氨基酸比例下降。为避免标准配方TPN可能引起的蛋白质代谢异常，可通过调整TPN配方中的氨基酸组成，增加支链氨基酸量，提高热氮比，以适应阻塞性黄疸时机体对营养物质的特殊需求。若仅从体内蛋白质代谢角度分析，外源性提供的氨基酸溶液配方越接近机体蛋白质合成的需要，就越易内化并合成新的蛋白质，从而有利于维持各组织器官的正常结构和功能。瑞金医院在阻塞性黄疸动物实验中比较了不同氮源的TPN对大鼠白蛋白合成和肠道粘膜形态学的效应，结果发现：含平衡型氨基酸溶液的TPN配方可以更有效地维持血浆白蛋白水平和肠道粘膜绒毛高度；在该配方中添加谷氨酰胺时，有助于预防由标准配方的TPN引起的肠道粘膜萎缩。同时，实验结果还提示：肠外营养支持可以提高阻黄动物的白蛋白mRNA水平，特别是应用含中/长链脂肪酸的脂肪乳剂加谷氨酰胺或高含量支链氨基酸的TPN配方时，更有利于白蛋白基因的转录。说明在阻塞性黄疸的病理状态下，应根据疾病严重程度和病人机体状况，个体化选择最合理的TPN配方，使阻塞性黄疸病人最大程度得益于营养支持。
迄今，临床上尚缺乏处理阻塞性黄疸伴有营养不良的成熟、有效的方法，只有在全面考虑个体病况后谨慎选择营养支持途径和配方，才可能达到改善病人营养状况的目的。
参考文献：
1.Mizock BA. Nutritional support in hepatic encephalopathy. Nutrition, 1999; 15 (3): 220
2.Lochs H, Plauth M. Liver cirrhosis: rationale and modalities for nutritional support ------ the European Society of Parenteral and Enteral Nutrition consensus and beyond. Curr Opin Clin Nutr Metab Care, 1999; 2 (4): 345
3.Fabbri A, Magrini N, Bianchi G, et al. Overview of randomized clinical trials of oral branched-chain amino acid treatment in chronic hepatic encephalopathy. JPEN, 1996; 20 (2): 159
4.Cordoba J, Sanpedro F, Planas M, et al. Protein metabolism at different levels of protein intake in cirrhotic patients with hepatic encephalopathy. Clin Nutr, 2000; 19 (S1): 40
5.Holecek M. Nutritional modulation of liver regeration by carbohydrates, lipids, and amino acids: a review. Nutrition, 1999; 15 (10): 784
6.Chuang JH, Chen WJ, Lo SK, et al. Adverse metabolic and microbiological effects of tube feeding in experimental canine obstructive jaundice. JPEN, 1997; 21 (1): 36, 百拇医药(费旭峰)
迄今，临床上尚缺乏处理阻塞性黄疸伴有营养不良的成熟、有效的方法，只有在全面考虑个体病况后谨慎选择营养支持途径和配方，才可能达到改善病人营养状况的目的。
参考文献：
1.Mizock BA. Nutritional support in hepatic encephalopathy. Nutrition, 1999; 15 (3): 220
2.Lochs H, Plauth M. Liver cirrhosis: rationale and modalities for nutritional support ------ the European Society of Parenteral and Enteral Nutrition consensus and beyond. Curr Opin Clin Nutr Metab Care, 1999; 2 (4): 345
3.Fabbri A, Magrini N, Bianchi G, et al. Overview of randomized clinical trials of oral branched-chain amino acid treatment in chronic hepatic encephalopathy. JPEN, 1996; 20 (2): 159
4.Cordoba J, Sanpedro F, Planas M, et al. Protein metabolism at different levels of protein intake in cirrhotic patients with hepatic encephalopathy. Clin Nutr, 2000; 19 (S1): 40
5.Holecek M. Nutritional modulation of liver regeration by carbohydrates, lipids, and amino acids: a review. Nutrition, 1999; 15 (10): 784
6.Chuang JH, Chen WJ, Lo SK, et al. Adverse metabolic and microbiological effects of tube feeding in experimental canine obstructive jaundice. JPEN, 1997; 21 (1): 36, 百拇医药(费旭峰)