Chinkes David L
Department of Surgery, University of Texas Medical Branch and Shriners Hospitals for Children, Galveston, Texas 77550, USA.
Curr Opin Clin Nutr Metab Care. 2005 Sep;8(5):534-7. doi: 10.1097/01.mco.0000170754.25372.37.
To describe the latest innovations in measuring protein breakdown in vivo, particularly in muscle.
The traditional method of using 3-methylhistidine excretion to measure muscle protein breakdown has been updated to include arteriovenous or microdialysis measurements, which address the concern that there are alternative sources of 3-methylhistidine in the body other than muscle. Several variations of a precursor-product method to measure fractional breakdown rate of tissues have been developed that are analogous to fractional synthesis rate of tissues. These methods are more generally applicable than the 3-methylhistidine methods and are less invasive than arteriovenous methods. The various precursor-product methods are distinguished by whether they require an isotopic steady state or multiple tracers and by how many biopsies are required.
The new precursor-product methods have enabled assessment in clinical trials of protein breakdown for proteins other than myofibrillar proteins and in circumstances in which arteriovenous sampling is not feasible.
描述体内蛋白质分解测量方面的最新创新，特别是在肌肉中的测量。
使用3-甲基组氨酸排泄来测量肌肉蛋白质分解的传统方法已得到更新，纳入了动静脉或微透析测量，解决了体内除肌肉外还有其他3-甲基组氨酸来源的问题。已开发出几种用于测量组织分解分数率的前体-产物法变体，类似于组织合成分数率。这些方法比3-甲基组氨酸法更具普遍适用性，且比动静脉法侵入性更小。各种前体-产物法的区别在于是否需要同位素稳态或多种示踪剂，以及需要多少次活检。
新的前体-产物法使得在临床试验中能够评估肌原纤维蛋白以外的蛋白质的分解情况，以及在动静脉采样不可行的情况下进行评估。
