Department of Endocrinology, Ghent University Hospital, Ghent, Belgium.
Symbiosis Centre for Medical Image Analysis, Symbiosis International (Deemed University), Pune, India.
Psychoneuroendocrinology. 2023 Oct;156:106337. doi: 10.1016/j.psyneuen.2023.106337. Epub 2023 Jul 23.
Recently, a variety of studies using different neuroimaging techniques attempted to identify the existence of a brain endophenotype in people with gender dysphoria (GD). However, despite mounting neuroimaging work, brain gender differences and effects of gender-affirming hormone therapy (GAHT) at the metabolite level remain understudied.
Thirty-one transgender men (TM) before and after testosterone administration (7.7 months ± 3.5 months), relative to 30 cisgender men (CM) and 35 cisgender women (CW) underwent magnetic resonance spectroscopy (H-MRS) at two time points. Two brain regions were assessed, i.e. the lateral parietal cortex and the amygdala/anterior hippocampus. Associated metabolites that were measured include N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), glutamate and glutamine (Glx), myo-inositol (mI), glycine (Gly) and their respective ratios.
A critical time by group interaction revealed an effect of GAHT in the lateral parietal cortex of TM. MI+Gly/Cr ratios decreased upon initiation of GAHT. In addition, NAA/Cr and Cho/Cr ratios were lower in CW when compared to CM in the lateral parietal cortex. Glx levels and Glx/Cr ratios in TM differed from those in CW in the amygdala/anterior hippocampus. Interestingly, pubertal age of onset of gender dysphoria (i.e. GD) in TM differentially affected testosterone-mediated effects on Cr concentration and NAA/Cr ratios when compared to childhood and adult GD onset in the amygdala/anterior hippocampus.
This H-MRS study demonstrated that testosterone administration shifts mI+Gly/Cr ratios in the parietal cortex. In the amygdala/anterior hippocampus, modulation of metabolite concentrations by age of onset of GD is suggestive for a possible developmental trend.
最近，各种使用不同神经影像学技术的研究试图在性别焦虑症（GD）患者中发现大脑内表型的存在。然而，尽管神经影像学研究不断增加，但大脑性别差异和性别肯定激素治疗（GAHT）对代谢物水平的影响仍研究不足。
31 名接受睾酮治疗前后的跨性别男性（TM）（7.7 个月±3.5 个月），与 30 名顺性别男性（CM）和 35 名顺性别女性（CW）相比，在两个时间点接受磁共振波谱（H-MRS）检查。评估了两个脑区，即外侧顶叶皮层和杏仁核/前海马。测量的相关代谢物包括 N-乙酰天冬氨酸（NAA）、肌酸（Cr）、胆碱（Cho）、谷氨酸和谷氨酰胺（Glx）、肌醇（mI）、甘氨酸（Gly）及其各自的比值。
关键的时间与组间交互作用显示了 GAHT 在 TM 外侧顶叶皮层的作用。GAHT 开始时，MI+Gly/Cr 比值降低。此外，在外侧顶叶皮层，CW 的 NAA/Cr 和 Cho/Cr 比值低于 CM。TM 的杏仁核/前海马中的 Glx 水平和 Glx/Cr 比值与 CW 不同。有趣的是，TM 中的性别焦虑症（GD）青春期发病年龄与儿童和成年 GD 发病相比，对杏仁核/前海马中 Cr 浓度和 NAA/Cr 比值的睾酮介导作用有不同的影响。
这项 H-MRS 研究表明，睾酮治疗改变了顶叶皮层的 mI+Gly/Cr 比值。在杏仁核/前海马中，GD 发病年龄对代谢物浓度的调节提示可能存在一种发育趋势。
