Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
PLoS One. 2011;6(10):e25340. doi: 10.1371/journal.pone.0025340. Epub 2011 Oct 5.
It has recently been hypothesized that hyperglutamatergia in the brain is involved in the pathophysiology of autism. However, there is no conclusive evidence of the validity of this hypothesis. As peripheral glutamate/glutamine levels have been reported to be correlated with those of the central nervous system, the authors examined whether the levels of 25 amino acids, including glutamate and glutamine, in the platelet-poor plasma of drug-naïve, male children with high-functioning autism (HFA) would be altered compared with those of normal controls.
METHODOLOGY/PRINCIPAL FINDINGS: Plasma levels of 25 amino acids in male children (N = 23) with HFA and normally developed healthy male controls (N = 22) were determined using high-performance liquid chromatography. Multiple testing was allowed for in the analyses. Compared with the normal control group, the HFA group had higher levels of plasma glutamate and lower levels of plasma glutamine. No significant group difference was found in the remaining 23 amino acids. The effect size (Cohen's d) for glutamate and glutamine was large: 1.13 and 1.36, respectively. Using discriminant analysis with logistic regression, the two values of plasma glutamate and glutamine were shown to well-differentiate the HFA group from the control group; the rate of correct classification was 91%.
CONCLUSIONS/SIGNIFICANCE: The present study suggests that plasma glutamate and glutamine levels can serve as a diagnostic tool for the early detection of autism, especially normal IQ autism. These findings indicate that glutamatergic abnormalities in the brain may be associated with the pathobiology of autism.
最近有人假设大脑中的高谷氨酸血症与自闭症的病理生理学有关。然而，目前尚无确凿证据证实这一假设的有效性。由于外周谷氨酸/谷氨酰胺水平与中枢神经系统的水平相关，作者研究了在未服用药物的高功能自闭症（HFA）男性儿童的血小板贫血浆中，包括谷氨酸和谷氨酰胺在内的 25 种氨基酸的水平是否会发生变化与正常对照组相比。
方法/主要发现：使用高效液相色谱法测定了 23 名 HFA 男性儿童（N=23）和正常发育的健康男性对照组（N=22）的血浆 25 种氨基酸水平。在分析中允许进行多次测试。与正常对照组相比，HFA 组的血浆谷氨酸水平较高，而血浆谷氨酰胺水平较低。在其余 23 种氨基酸中未发现显著的组间差异。谷氨酸和谷氨酰胺的效应大小（Cohen's d）较大：分别为 1.13 和 1.36。使用具有逻辑回归的判别分析，显示血浆谷氨酸和谷氨酰胺的两个值可以很好地区分 HFA 组和对照组；正确分类率为 91%。
结论/意义：本研究表明，血浆谷氨酸和谷氨酰胺水平可作为自闭症早期检测的诊断工具，特别是正常智商自闭症。这些发现表明，大脑中的谷氨酸能异常可能与自闭症的病理生物学有关。
