Patients with brain tumors have an increased risk for depression, whose underlying pathomechanism may involve dysregulated tryptophan/kynurenine metabolism. In this study, we analyzed the relation of depressive symptoms to clinical and tumor characteristics as well as cerebral and systemic tryptophan metabolism in patients with primary brain tumors. Sixty patients with newly-diagnosed or recurrent primary brain tumor underwent testing with the Beck Depression Inventory-II (BDI-II), and 34 patients also had positron emission tomography (PET) imaging with alpha-[¹¹C]methyl-L-tryptophan (AMT). BDI-II scores were correlated with clinical and tumor-related variables, cerebral regional AMT metabolism measured in the non-tumoral hemisphere, and plasma tryptophan metabolite levels. Sixteen patients (27%) had BDI-II scores indicating depression, including 6 with moderate/severe depression. High BDI-II scores were independent of clinical and tumor-related variables except lower Karnofsky Performance Status scores. In patients with recurrent malignant gliomas, depression was associated with shorter survival (hazard ratio: 3.7; p = 0.048). High BDI-II total and somatic subscale scores were associated with higher frontal cortical and thalamic AMT metabolic values measured on PET. In contrast, plasma tryptophan and kynurenine metabolite levels did not correlate with the BDI-II scores. In conclusion, our results confirm previous data that depression affects more than ¼ of patients with primary brain tumors, it is largely independent of tumor characteristics and is associated with shorter survival in patients with recurrent malignant gliomas. On PET imaging, higher tryptophan metabolism in the frontal cortex and thalamus was found in those with brain tumor-associated depression and supports the role of dysregulated tryptophan/kynurenine metabolism in this condition.

脑肿瘤患者患抑郁症的风险增加，其潜在的发病机制可能涉及色氨酸/犬尿氨酸代谢失调。在这项研究中，我们分析了原发性脑肿瘤患者抑郁症状与临床和肿瘤特征以及脑和全身色氨酸代谢的关系。60 名新诊断或复发性原发性脑肿瘤患者接受了贝克抑郁量表-II (BDI-II) 检测，34 名患者还接受了 α-[ ^{11正电子发射断层扫描 (PET) 成像}C]甲基-L-色氨酸（AMT）。BDI-II 评分与临床和肿瘤相关变量、在非肿瘤半球测量的大脑区域 AMT 代谢和血浆色氨酸代谢物水平相关。16 名患者 (27%) 的 BDI-II 评分表明抑郁症，其中 6 名患有中度/重度抑郁症。高 BDI-II 评分与临床和肿瘤相关变量无关，除了较低的 Karnofsky 表现状态评分。在复发性恶性胶质瘤患者中，抑郁症与较短的生存期相关（风险比：3.7；p = 0.048）。高 BDI-II 总分和体细胞分量表得分与 PET 上测量的较高的额叶皮质和丘脑 AMT 代谢值相关。相比之下，血浆色氨酸和犬尿氨酸代谢物水平与 BDI-II 评分无关。综上所述，我们的研究结果证实了先前的数据，即抑郁症影响超过 1/4 的原发性脑肿瘤患者，它在很大程度上与肿瘤特征无关，并且与复发性恶性胶质瘤患者的生存期较短有关。在 PET 成像中，在脑肿瘤相关性抑郁症患者中发现额叶皮层和丘脑中较高的色氨酸代谢，并支持色氨酸/犬尿氨酸代谢失调在这种情况下的作用。