Chappell Derek L, McAvoy Thomas, Weiss Barbra, Weiner Russell, Laterza Omar F
Clinical Development Laboratory, 126 E Lincoln Avenue, Rahway, NJ 07065, USA.
Bioanalysis. 2012 Dec;4(23):2843-50. doi: 10.4155/bio.12.268.
Renin catalyzes the conversion of angiotensinogen to angiotensin I (Ang I), the first and rate-limiting step in the renin-angiotensin-aldosterone system. Plasma renin activity (PRA) is an important target engagement biomarker in the clinical development of renin inhibitors. We have developed and validated an improved PRA assay that incorporates an Ang I trapping antibody followed by extraction and quantification of Ang I using a highly sensitive and specific LC-MS/MS method.
The following assay performance characteristics were assessed as part of analytical validation: precision, LOQ, spike recovery, dilution linearity, stability, absolute recovery and biological variability. The assay demonstrated excellent performance characteristics. Notably, the sensitivity of the assay was increased 140-fold when compared with a previous enzyme immunoassay-based assay.
The improved sensitivity allowed the measurement of >95% PRA inhibition from baseline levels. In addition, we compared the LC-MS/MS-based assay to an enzyme immunoassay-based assay.
肾素催化血管紧张素原转化为血管紧张素I（Ang I），这是肾素-血管紧张素-醛固酮系统的第一步且为限速步骤。血浆肾素活性（PRA）是肾素抑制剂临床开发中的一个重要靶点结合生物标志物。我们开发并验证了一种改进的PRA测定方法，该方法采用一种Ang I捕获抗体，随后使用高灵敏度和特异性的液相色谱-串联质谱（LC-MS/MS）方法对Ang I进行提取和定量。
作为分析验证的一部分，评估了以下测定性能特征：精密度、定量下限、加标回收率、稀释线性、稳定性、绝对回收率和生物变异性。该测定方法表现出优异的性能特征。值得注意的是，与先前基于酶免疫测定的方法相比，该测定方法的灵敏度提高了140倍。
提高的灵敏度使得能够从基线水平测量>95%的PRA抑制率。此外，我们将基于LC-MS/MS的测定方法与基于酶免疫测定的方法进行了比较。
