Dramatic elevation in urinary amino terminal titin fragment excretion quantified by immunoassay in Duchenne muscular dystrophy patients and in dystrophin deficient rodents
Dramatic elevation in urinary amino terminal titin fragment excretion quantified by immunoassay in Duchenne muscular dystrophy patients and in dystrophin deficient rodents
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DOI：
10.1016/j.nmd.2017.05.009
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发表时间：
2017-07-01
影响因子：
2.8
通讯作者：
Stimpson, Stephen A.
中科院分区：
文献类型：
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作者：
Robertson, Alan S.;Majchrzak, Mark J.;Stimpson, Stephen A.
建立了定量测定骨骼肌蛋白Titin(N-titin)氨基(N-)末端片段的酶联免疫测定法和电化学发光免疫测定法，可用于检测尿N-titin排泄量。正常人的尿中含有少量但可测量的N-三联滴定(1.0+/-0.4 ng/ml)。Duchene型肌营养不良症患者尿N-肌动蛋白排泄量增加365倍(365.4+/-65.0，P=0.0001)。在dystrophin缺乏的啮齿动物模型中，也对尿N-Ter-titin进行了评估。MDX小鼠在2周龄时表现出较低的尿N-滴度水平，随后在3周龄时开始出现强劲而持续的升高，这与该模型中全身骨骼肌损伤的发展相一致；由于在年龄匹配的野生型小鼠中未检测到尿N-滴度，因此无法确定折叠升高的程度。血清肌酸激酶和骨骼肌肌钙蛋白I(TnI)水平在2周时也较低，在以后的时间点升高，并与尿N-tititin排泄量显著相关。对MDX小鼠进行皮质类固醇治疗后，运动能力得到改善，尿N-三磷酸肌苷和血清骨骼肌TnI浓度均降低。5个月龄时，野生型大鼠尿液中N-三磷酸肌醇水平较低(3.00/-0.60 ng/ml)，而二甲基亚硝胺(DMD)大鼠(1652.5+/-405.7 ng/ml，P=0.002)。这些结果表明，正常尿液中N-Ter-titin存在于较低的基础浓度，并且随着dystrophin缺乏症引起的肌肉损伤而显著增加。尿N-滴蛋白作为DMD的一种简便、无创、可翻译的生物标志物具有潜在的潜力。(C)2017年作者。爱思唯尔出版公司(Elsevier B.V.)
Enzyme-linked and electrochemiluminescenCe immunoassays were developed for quantification of amino (N-) terminal fragments of the skeletal muscle protein titin (N-ter titin) and qualified for use in detection of urinary N-ter titin excretion. Urine from normal subjects contained a small but measurable level of N-ter titin (1.0 +/- 0.4 ng/ml). A 365-fold increase (365.4 +/- 65.0, P = 0.0001) in urinary N-ter titin excretion was seen in Duchene muscular dystrophy (DMD) patients. Urinary N-ter titin was also evaluated in dystrophin deficient rodent models. Mdx mice exhibited low urinary N-ter titin levels at 2 weeks of age followed by a robust and sustained elevation starting at 3 weeks of age, coincident with the development of systemic skeletal muscle damage in this model; fold elevation could not be determined because urinary N-ter titin was not detected in age-matched wild type mice. Levels of serum creatine kinase and serum skeletal muscle troponin I (TnI) were also low at 2 weeks, elevated at later time points and were significantly correlated with urinary N-ter titin excretion in mdx mice. Corticosteroid treatment of mdx mice resulted in improved exercise performance and lowering of both urinary N-ter titin and serum skeletal muscle TnI concentrations. Low urinary N-ter titin levels were detected in wild type rats (3.0 +/- 0.6 ng/ml), while Dmd(mdx) rats exhibited a 556-fold increase (1652.5 +/- 405.7 ng/ml, P = 0.002) (both at 5 months of age). These results suggest that urinary N-ter titin is present at low basal concentrations in normal urine and increases dramatically coincident with muscle damage produced by dystrophin deficiency. Urinary N-ter titin has potential as a facile, non-invasive and translational biomarker for DMD. (C) 2017 The Authors. Published by Elsevier B.V.