Bartzokis G, Beckson M, Hance D B, Marx P, Foster J A, Marder S R
Research Service, West Los Angeles VA Medical Center, CA 90073, USA.
Magn Reson Imaging. 1997;15(1):29-35. doi: 10.1016/s0730-725x(96)00234-2.
The purposes of this study were to extend the investigation of age-related increases in brain iron to a younger age group, replicate previously published results, and further evaluate the validity of a novel noninvasive magnetic resonance (MR) method for measuring tissue iron (ferritin) levels with specificity. The method consists of measuring the dependence of tissue transverse relaxation rates (R2) on the field strength of MR instruments. Two MR instruments operating at 1.5 and 0.5 T were used to measure the field-dependent R2 increase (FDRI) in the frontal white matter, caudate, putamen, and globus pallidus. A group of 13 normal adult males (ages 21-77), with seven subjects below and six above age 35, was examined. As expected from postmortem and prior FDRI data, robust and significant age-related increases in FDRI were observed in the caudate, putamen, and globus pallidus, with the globus pallidus FDRI increasing sharply in the second decade and reaching a plateau after age 30. In addition, we replicated previous reports showing very high correlations between FDRI and published brain iron levels for the four regions examined. The data replicate and extend previous FDRI observations on brain aging and are consistent with postmortem data on age-related increases in brain iron. These results are relevant to the investigation of age-related neurodegenerative diseases in which iron may catalyze toxic free radical reactions.
本研究的目的是将与年龄相关的脑铁增加的研究扩展到更年轻的年龄组，重复先前发表的结果，并进一步评估一种新型非侵入性磁共振（MR）方法在特异性测量组织铁（铁蛋白）水平方面的有效性。该方法包括测量组织横向弛豫率（R2）对MR仪器场强的依赖性。使用两台分别运行在1.5T和0.5T的MR仪器来测量额叶白质、尾状核、壳核和苍白球中与场强相关的R2增加（FDRI）。对一组13名正常成年男性（年龄21 - 77岁）进行了检查，其中7名受试者年龄低于35岁，6名高于35岁。正如从尸检和先前的FDRI数据所预期的那样，在尾状核、壳核和苍白球中观察到了与年龄相关的FDRI显著且强劲的增加，苍白球的FDRI在第二个十年急剧增加，并在30岁后达到平台期。此外，我们重复了先前的报告，显示在所检查的四个区域中，FDRI与已发表的脑铁水平之间具有非常高的相关性。这些数据重复并扩展了先前关于脑老化的FDRI观察结果，并且与关于与年龄相关的脑铁增加的尸检数据一致。这些结果与对与年龄相关的神经退行性疾病的研究相关，在这些疾病中铁可能催化有毒的自由基反应。
