Hüfner Katharina, Giesinger Johannes M, Gostner Johanna M, Egeter Jonas, Koudouovoh-Tripp Pia, Vill Theresa, Fuchs Dietmar, Sperner-Unterweger Barbara
University Clinic for Psychiatry II, Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, Austria.
Institute of Medical Biochemistry, Biocenter, Medical University of Innsbruck, Austria.
Int J Tryptophan Res. 2021 Sep 1;14:11786469211039220. doi: 10.1177/11786469211039220. eCollection 2021.
The immunomodulatory capacity of mental stress is one of the basic concepts of psychoneuroimmunology. The current prospective longitudinal study was designed to evaluate the effect of acute mental stress on neurotransmitter precursor amino acid levels in individuals with depression at 2 time points. Ten physically healthy patients with a diagnosis of major depressive episode and Montgomery-Åsberg Depression Rating Scale scores (MADRAS) ⩾20 points at inclusion were assessed on 2 study days (once with higher MADRAS scores, once with lower MADRAS scores; median 34.5 days apart) and subjected to a standardized acute mental stress test on each study day. Blood was collected at 4 time points: once prior to and at 3 time points (0, 30 minutes, 60 minutes) following mental stress. Neurotransmitter precursor amino acid levels, that is kynurenine/tryptophan (KYN/TRP) and phenylalanine/tyrosine (PHE/TYR), as well as neopterin and nitrite were analyzed in a total of 80 individual blood samples. Regression and correlation analyses were performed. Regression analyses of PHE/TYR ( = .547) and KYN/TRP ( = .440) in relation to MADRAS depression severity showed a quadratic curve fit. This was reflected by a negative linear correlation between MADRAS scores and PHE/TYR as well as KYN/TRP in the lower score range ( = -.805, < .001 and = -.586, < .001 respectively) and a positive correlation in the higher MADRAS score range ( = .713, < .001 and = .379, = .016 respectively). No effect of acute mental stress was found. This analysis exemplifies the implications of sampling as well as data distributions on results. The crosstalk of biological mechanisms that orchestrate metabolic and immunological signaling may vary depending on depression severity resulting in non-linear associations that may explain the heterogeneity of results found in the literature.
心理应激的免疫调节能力是心理神经免疫学的基本概念之一。当前这项前瞻性纵向研究旨在评估急性心理应激对抑郁症患者在两个时间点神经递质前体氨基酸水平的影响。纳入了10名身体状况健康、诊断为重度抑郁发作且蒙哥马利-阿斯伯格抑郁评定量表（MADRAS）评分在纳入时⩾20分的患者，在两个研究日进行评估（一次MADRAS评分较高，一次评分较低；间隔中位数为34.5天），并在每个研究日接受标准化急性心理应激测试。在4个时间点采集血液：一次在心理应激前，以及心理应激后的3个时间点（0、30分钟、60分钟）。总共80份个体血样中分析了神经递质前体氨基酸水平，即犬尿氨酸/色氨酸（KYN/TRP）和苯丙氨酸/酪氨酸（PHE/TYR），以及新蝶呤和亚硝酸盐。进行了回归和相关性分析。PHE/TYR（ = .547）和KYN/TRP（ = .440）与MADRAS抑郁严重程度的回归分析显示呈二次曲线拟合。这表现为在较低评分范围内MADRAS评分与PHE/TYR以及KYN/TRP呈负线性相关（分别为 = -.805， < .001和 = -.586， < .001），而在较高MADRAS评分范围内呈正相关（分别为 = .713， < .001和 = .379， = .016）。未发现急性心理应激有影响。该分析例证了采样以及数据分布对结果的影响。协调代谢和免疫信号传导的生物学机制之间的相互作用可能因抑郁严重程度而异，从而导致非线性关联，这可能解释了文献中所发现结果的异质性。
