Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults.
Effectiveness of essential amino acid supplementation in stimulating whole body net protein anabolism is comparable between COPD patients and healthy older adults.
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DOI：
10.1016/j.metabol.2016.12.010
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发表时间：
2017-04
期刊：
影响因子：
--
通讯作者：
Engelen MP
中科院分区：
文献类型：
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作者：
Jonker R;Deutz NE;Erbland ML;Anderson PJ;Engelen MP
开发有效的营养策略以支持慢性阻塞性肺疾病（COPD）患者的肌肉生长仍然具有挑战性。膳食必需氨基酸（EAA）是餐后净蛋白质摄入的主要驱动力。在协议中，EAA补充剂在健康的老年人比补充剂与完整的蛋白质的组成更有效。在COPD患者中，完全蛋白质补充剂是否可以仅用EAA替代，以及它们是否与健康老年人一样有效，仍然是未知的。按照双盲随机交叉设计，我们检查了23例中重度COPD患者（年龄：65 ± 2岁，FEV 1：预测值的40 ± 2%）和19名年龄匹配的健康受试者（年龄：64 ± 2岁），是否含有高比例（40%）亮氨酸的游离EAA混合物（EAA混合物）比乳清蛋白中存在的平衡游离EAA和非EAA的类似混合物（TAA混合物）更能刺激全身净蛋白质增加。通过连续IV输注L-[ring-2 H5]-PHE和L-[ring-2 H2]-酪氨酸以及肠内摄入L-[15 N]-PHE（添加到混合物中）来评估全身净蛋白质增益和苯丙氨酸（PHE）的内脏提取。除了两组中PHE摄入量与净蛋白质增加量之间存在良好的正线性关系（r=0.84-0.91，P<0.001）之外，与TAA混合物相比，摄入EAA混合物后，健康对照组的净蛋白质增加量高42%，COPD患者高49%（P<0.0001）。这些发现不能归因于高LEU含量，因为在两组中，EAA混合物每克EAA摄入的净蛋白质增益较低（P<0.0001）。两种混合物在COPD患者中的净蛋白质增加更高，这是由于内脏提取物降低了40%（P<0.0001），但与饮食PHE（即EAA）血浆外观类似地相关。在COPD患者中，类似于健康的老年人，游离EAA补充剂比具有完整蛋白质组成的游离氨基酸补充剂更能刺激全身蛋白质合成。因此，免费EAA补充剂可能有助于预防和治疗该患者人群的肌肉萎缩。ClinicalTrials.gov;编号：NCT 01173354和NCT 01172314; URL：www.clinicaltrials.gov
The development of effective nutritional strategies in support of muscle growth for patients with chronic obstructive pulmonary disease (COPD) remains challenging. Dietary essential amino acids (EAAs) are the main driver of postprandial net protein anabolism. In agreement, EAA supplements in healthy older adults are more effective than supplements with the composition of complete proteins. In patients with COPD it is still unknown whether complete protein supplements can be substituted with only EAAs, and whether they are as effective as in healthy older adults. According to a double-blind randomized crossover design, we examined in 23 patients with moderate to very severe COPD (age: 65 ± 2 y, FEV1: 40 ± 2% of predicted) and 19 healthy age-matched subjects (age: 64 ± 2 y), whether a free EAA mixture with a high proportion (40%) of leucine (EAA mixture) stimulated whole body net protein gain more than a similar mixture of balanced free EAAs and non-EAAs as present in whey protein (TAA mixture). Whole body net protein gain and splanchnic extraction of phenylalanine (PHE) were assessed by continuous IV infusion of L-[ring-2H5]-PHE and L-[ring-2H2]-tyrosine, and enteral intake of L-[15N]-PHE (added to the mixtures). Besides an excellent positive linear relationship between PHE intake and net protein gain in both groups (r=0.84–0.91, P<0.001), net protein gain was 42% higher in healthy controls and 49% higher in COPD patients after intake of the EAA mixture compared to the TAA mixture (P<0.0001). These findings could not be attributed to the high LEU content, as in both groups net protein gain per gram EAA intake was lower for the EAA mixture (P<0.0001). Net protein gain was higher in COPD patients for both mixtures due to a 40% lower splanchnic extraction (P<0.0001), but was similarly related to dietary PHE (i.e. EAA) plasma appearance. In COPD patients, similarly to healthy older adults, free EAA supplements stimulate whole body protein anabolism more than free amino acid supplements with the composition of complete proteins. Therefore, free EAA supplements may aid in the prevention and treatment of muscle wasting in this patient population. ClinicalTrials.gov; Nos.: NCT01173354 and NCT01172314; URL: www.clinicaltrials.gov