From the Departments of Neurology (N.M.V., Z.K., J.V., E.H.N.), Biomedical Data Sciences (M.S.), Human Genetics (N.V., M.O., P.S.), and Clinical Chemistry and Laboratory Medicine (J.A.B.), Leiden University Medical Center, the Netherlands; Duchenne Center Netherlands (N.M.V., J.V., P.S., E.H.N.); European Reference Network for Rare Neuromuscular Diseases [ERN EURO-NMD] (N.M.V., Z.K., N.V., M.O., J.V., P.S., E.H.N.); Mathematical Institute (M.S.), Leiden University, the Netherlands; Analysis Group Inc (G.S., J.S.), Boston, MA; Solid Biosciences Inc (V.R., K.B.), Cambridge, MA; and NIHR Great Ormond Street Hospital Biomedical Research Centre (V.R.), Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, United Kingdom.
Neurology. 2023 Feb 28;100(9):e975-e984. doi: 10.1212/WNL.0000000000201609. Epub 2022 Dec 5.
The slow and variable disease progression of Becker muscular dystrophy (BMD) urges the development of biomarkers to facilitate clinical trials. We explored changes in 3 muscle-enriched biomarkers in serum of patients with BMD over 4-year time and studied associations with disease severity, disease progression, and dystrophin levels in BMD.
We quantitatively measured creatine kinase (CK) using the International Federation of Clinical Chemistry reference method, creatine/creatinine (Cr/Crn) using liquid chromatography-tandem mass spectrometry, and myostatin with ELISA in serum and assessed functional performance using the North Star Ambulatory Assessment (NSAA), 10-meter run velocity (TMRv), 6-Minute Walking Test (6MWT), and forced vital capacity in a 4-year prospective natural history study. Dystrophin levels were quantified in the tibialis anterior muscle using capillary Western immunoassay. The correlation between biomarkers, age, functional performance, mean annual change, and prediction of concurrent functional performance was analyzed using linear mixed models.
Thirty-four patients with 106 visits were included. Eight patients were nonambulant at baseline. Cr/Crn and myostatin were highly patient specific (intraclass correlation coefficient for both = 0.960). Cr/Crn was strongly negatively correlated, whereas myostatin was strongly positively correlated with the NSAA, TMRv, and 6MWT (Cr/Crn rho = -0.869 to -0.801 and myostatin rho = 0.792 to 0.842, all < 0.001). CK showed a negative association with age ( = 0.0002) but was not associated with patients' performance. Cr/Crn and myostatin correlated moderately with the average annual change of the 6MWT (rho = -0.532 and 0.555, = 0.02). Dystrophin levels did not correlate with the selected biomarkers nor with performance. Cr/Crn, myostatin, and age could explain up to 75% of the variance of concurrent functional performance of the NSAA, TMRv, and 6MWT.
Both Cr/Crn and myostatin could potentially serve as monitoring biomarkers in BMD, as higher Cr/Crn and lower myostatin were associated with lower motor performance and predictive of concurrent functional performance when combined with age. Future studies are needed to more precisely determine the context of use of these biomarkers.
贝克型肌营养不良症（BMD）的疾病进展缓慢且具有变异性，这促使我们开发生物标志物以促进临床试验。我们探讨了 4 年内 BMD 患者血清中 3 种肌肉丰富的生物标志物的变化，并研究了这些标志物与疾病严重程度、疾病进展和 BMD 中肌营养不良蛋白水平的相关性。
我们使用国际临床化学联合会参考方法定量测定肌酸激酶（CK），使用液相色谱-串联质谱法测定肌酸/肌酐（Cr/Crn），使用 ELISA 测定肌肉生长抑制素（myostatin），并使用北星动态评估（NSAA）、10 米跑速度（TMRv）、6 分钟步行测试（6MWT）和用力肺活量评估 4 年前瞻性自然史研究中的功能表现。使用毛细管 Western 免疫测定法在比目鱼肌中定量测定肌营养不良蛋白水平。使用线性混合模型分析了生物标志物与年龄、功能表现、年均变化以及对同期功能表现的预测之间的相关性。
共纳入 34 例患者，共 106 次就诊。基线时有 8 例患者无法行走。Cr/Crn 和肌肉生长抑制素具有高度的个体特异性（两者的组内相关系数均为 0.960）。Cr/Crn 与 NSAA、TMRv 和 6MWT 呈强烈负相关，而肌肉生长抑制素与 NSAA、TMRv 和 6MWT 呈强烈正相关（Cr/Crn rho = -0.869 至 -0.801，肌肉生长抑制素 rho = 0.792 至 0.842，均<0.001）。CK 与年龄呈负相关（=0.0002），但与患者的表现无关。Cr/Crn 和肌肉生长抑制素与 6MWT 的年均变化中度相关（rho = -0.532 和 0.555，=0.02）。肌营养不良蛋白水平与所选生物标志物或表现均无相关性。Cr/Crn、肌肉生长抑制素和年龄可以解释 NSAA、TMRv 和 6MWT 同期功能表现的高达 75%的变异性。
Cr/Crn 和肌肉生长抑制素均可能作为 BMD 的监测生物标志物，因为较高的 Cr/Crn 和较低的肌肉生长抑制素与较低的运动表现相关，并且当与年龄结合时可预测同期的功能表现。未来的研究需要更精确地确定这些生物标志物的使用范围。
