Institute of Clinical Physiology, National Research Council (CNR), Via Savi, 10, 56126, Pisa, Italy.
Turku PET Centre, University of Turku, Turku, Finland.
Sci Rep. 2022 Jul 7;12(1):11530. doi: 10.1038/s41598-022-15670-0.
N-acetylaspartate (NAA) is the second most abundant metabolite in the human brain; although it is assumed to be a proxy for a neuronal marker, its function is not fully elucidated. NAA is also detectable in plasma, but its relation to cerebral NAA levels, cognitive performance, or features of cerebral disease has not been investigated. To study whether circulating NAA tracks cerebral NAA levels, and whether circulating NAA correlates with cognitive function and features of cerebral small vessel disease (SVD). Two datasets were analyzed. In dataset 1, structural MRI was acquired in 533 subjects to assess four features of cerebral SVD. Cognitive function was evaluated with standardized test scores (N = 824). In dataset 2, brain H-MRS from the occipital region was acquired (N = 49). In all subjects, fasting circulating NAA was measured with mass spectrometry. Dataset 1: in univariate and adjusted for confounders models, we found no correlation between circulating NAA and the examined features of cerebral SVD. In univariate analysis, circulating NAA levels were associated inversely with the speed in information processing and the executive function score, however these associations were lost after accounting for confounders. In line with the negative findings of dataset 1, in dataset 2 there was no correlation between circulating and central NAA or total NAA levels. This study indicates that circulating NAA levels do not reflect central (occipital) NAA levels, cognitive function, or cerebral small vessel disease in man.
N- 乙酰天冬氨酸（NAA）是人体内含量第二丰富的代谢物；尽管它被认为是神经元标志物的替代物，但它的功能尚未完全阐明。NAA 也可在血浆中检测到，但它与大脑 NAA 水平、认知表现或脑小血管疾病（SVD）特征的关系尚未被研究。为了研究循环 NAA 是否与大脑 NAA 水平相关，以及循环 NAA 是否与认知功能和脑小血管疾病特征相关。分析了两个数据集。在数据集 1 中，对 533 名受试者进行了结构 MRI 采集，以评估脑 SVD 的四个特征。采用标准化测试分数评估认知功能（N=824）。在数据集 2 中，采集了枕叶区域的脑 H-MRS（N=49）。在所有受试者中，均采用质谱法测量空腹循环 NAA。数据集 1：在单变量和调整混杂因素的模型中，我们没有发现循环 NAA 与脑 SVD 的检查特征之间存在相关性。在单变量分析中，循环 NAA 水平与信息处理速度和执行功能评分呈负相关，但在考虑混杂因素后，这些相关性消失了。与数据集 1 的阴性结果一致，在数据集 2 中，循环和中央 NAA 或总 NAA 水平之间没有相关性。这项研究表明，循环 NAA 水平不能反映人体内的中央（枕叶）NAA 水平、认知功能或脑小血管疾病。
