PDF(Pubmed)
Abstract：
Although the standard method to evaluate skeletal muscle protein synthesis (MPS) is muscle biopsy, the method is invasive and problematic for multisite use. We conducted a small pilot study in volunteers to investigate changes in MPS according to skeletal muscle site using a noninvasive method in which 6 healthy young men were given yogurt (containing 20 g milk protein) or water, and 1 h later, l-[11C]methionine ([11C]Met) was administered intravenously. Dynamic PET/CT imaging of their thighs was performed for 60 min. The influx constant Ki of [11C]Met in skeletal muscle protein was calculated as an index of MPS using a Patlak plot, and found to be 0.6%-28% higher after ingesting yogurt than after water in 5 of the 6 volunteer participants, but it was 34% lower in the remaining participant. Overall, this indicated no significant increase in Ki after ingesting milk protein. However, when the quadriceps and hamstring muscles were analyzed separately, we found a significant difference in Ki. This demonstrates the potential of visualizing MPS by calculating the Ki for each voxel and reconstructing it as an image, which presents unique advantages of [11C]Met PET/CT for evaluating MPS, such as site-specificity and visualization.
摘要：
虽然评估骨骼肌蛋白合成（MPS）的标准方法是肌肉活检，该方法是侵入性的，并且对于多站点使用存在问题。我们在志愿者中进行了一项小型试点研究，以使用非侵入性方法根据骨骼肌部位调查MPS的变化，其中6名健康的年轻男性被给予酸奶（含有20克乳蛋白）或水，1小时后，静脉内施用1-[11C]甲硫氨酸([11C]Met)。对他们的大腿进行动态PET/CT成像60分钟。使用Patlak图计算骨骼肌蛋白中[11C]Met的流入常数Ki作为MPS的指数，在6名志愿者中的5名参与者中，摄入酸奶后比喝水后高0.6%-28%，但其余参与者的比例降低了34%。总的来说,这表明摄入牛奶蛋白后Ki没有显着增加。然而,当分别分析股四头肌和腿筋肌肉时，我们发现Ki有显著差异。这证明了通过计算每个体素的Ki并将其重建为图像来可视化MPS的潜力，[11C]MetPET/CT在评估MPS方面具有独特的优势，如位点特异性和可视化。
