Chang L, Ernst T, Poland R E, Jenden D J
Department of Neurology, Harbor-UCLA Medical Center, Torrance, USA.
Life Sci. 1996;58(22):2049-56. doi: 10.1016/0024-3205(96)00197-x.
The effect of age on brain metabolite concentrations was evaluated using localized proton magnetic resonance spectroscopy. This technique allows in vivo measurements of N-acetyl compounds (NA), total creatine (CR), choline-containing compounds (CHO), myo-inositol (MI), glutamate and glutamine (GLX), as well as the percentage of cerebrospinal fluid (CSF) and the brain water content within the brain region studied. Frontal gray matter and frontal white matter brain regions were examined in 36 normal healthy volunteers (19-78 years of age). Using a rigorous absolute quantitation method, with an external reference and atrophy correction, we found relatively stable concentrations of NA, a neuronal marker. In contrast, CR, CHO, MI, and the percentage of CSF increased in the gray matter with age. However, the brain water content decreased significantly with age (r = -0.72; p < 0.0001). No significant age-related changes in metabolite concentrations, CSF or brain water content were observed in the white matter regions. These findings demonstrate that biochemical alterations are associated with aging in the frontal gray matter. There might be an increase in the brain density as indicated by increased metabolite concentrations and decreased brain water content with aging.
采用局部质子磁共振波谱法评估年龄对脑代谢物浓度的影响。该技术可在体内测量N-乙酰化合物（NA）、总肌酸（CR）、含胆碱化合物（CHO）、肌醇（MI）、谷氨酸和谷氨酰胺（GLX），以及所研究脑区内脑脊液（CSF）的百分比和脑含水量。对36名正常健康志愿者（19 - 78岁）的额叶灰质和额叶白质脑区进行了检查。使用一种严格的绝对定量方法，并采用外部参考和萎缩校正，我们发现神经元标志物NA的浓度相对稳定。相比之下，灰质中的CR、CHO、MI以及CSF的百分比随年龄增长而增加。然而，脑含水量随年龄显著下降（r = -0.72；p < 0.0001）。在白质区域未观察到与年龄相关的代谢物浓度、CSF或脑含水量的显著变化。这些发现表明，额叶灰质中的生化改变与衰老有关。随着年龄增长，代谢物浓度增加和脑含水量降低，可能表明脑密度增加。
