Department of Anesthesiology and Intensive Care Medicine at Karolinska University Hospital Huddinge and Karolinska Institutet, Stockholm, Sweden.
Department of Anesthesiology and Intensive Care Medicine at Karolinska University Hospital Huddinge and Karolinska Institutet, Stockholm, Sweden.
Clin Nutr. 2015 Feb;34(1):95-100. doi: 10.1016/j.clnu.2014.01.020. Epub 2014 Feb 5.
BACKGROUND & AIMS: To evaluate the effect of nutrition therapy on protein turnover in critically ill patients isotopically labeled amino acids can be used. Here parallel measurements using (13)C-leucine and (2)H5-phenylalanine were performed to evaluate if one tracer was to be preferred.
As a reference group, healthy volunteers (n = 8) were studied in the postabsorptive state and during parenteral nutrition delivery. ICU patients with multiple organ failure (n = 8) were studied during parenteral nutrition delivery only.
For the volunteers, the net protein balances changed from negative to positive during parenteral nutrition delivery (compared to the postabsorptive state) when evaluated with leucine and phenylalanine (P < 0.0001). For phenylalanine this change was attributable to an increased protein synthesis (P < 0.0001), while for leucine the change was attributable to a decreased protein degradation (P < 0.0001). For the patients, only measured during parenteral nutrition delivery, the estimates by the two amino acid tracers agreed, showing a protein balance not statistically significantly different from zero. The whole body protein turnover was higher than that of the healthy volunteers during parenteral nutrition delivery. In the patients, the net protein balance correlated positively to the amount of amino acids given.
Critically ill patients with multiple organ failure have an increased protein turnover. The findings in the healthy volunteers indicate that the use of the two different amino acid tracers in parallel in future studies should be considered.
为了评估营养疗法对危重症患者蛋白质周转率的影响，可以使用同位素标记的氨基酸。本研究采用（13）C-亮氨酸和（2）H5-苯丙氨酸平行测量，以评估是否有一种示踪剂更优。
作为参考组，健康志愿者（n=8）在吸收后状态和肠外营养输注期间进行了研究。患有多器官衰竭的 ICU 患者（n=8）仅在肠外营养输注期间进行了研究。
对于志愿者，与吸收后状态相比，在肠外营养输注期间（用亮氨酸和苯丙氨酸评估时），净蛋白质平衡从负值变为正值（P＜0.0001）。对于苯丙氨酸，这种变化归因于蛋白质合成增加（P＜0.0001），而对于亮氨酸，这种变化归因于蛋白质降解减少（P＜0.0001）。对于仅在肠外营养输注期间测量的患者，两种氨基酸示踪剂的估计值一致，表明蛋白质平衡与零无统计学差异。全身蛋白质周转率在肠外营养输注期间高于健康志愿者。在患者中，净蛋白质平衡与给予的氨基酸量呈正相关。
患有多器官衰竭的危重症患者蛋白质周转率增加。健康志愿者的研究结果表明，在未来的研究中应考虑平行使用两种不同的氨基酸示踪剂。
