Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
Mental Health Research Center (MHRC), The Hong Kong Polytechnic University, Hong Kong SAR, China.
Int J Mol Sci. 2022 Aug 26;23(17):9692. doi: 10.3390/ijms23179692.
Abnormal activation of the kynurenine and serotonin pathways of tryptophan metabolism is linked to a host of neuropsychiatric disorders. Concurrently, noninvasive brain stimulation (NIBS) techniques demonstrate high therapeutic efficacy across neuropsychiatric disorders, with indications for modulated neuroplasticity underlying such effects. We therefore conducted a scoping review with meta-analysis of eligible studies, conforming with the PRISMA statement, by searching the PubMed and Web of Science databases for clinical and preclinical studies that report the effects of NIBS on biomarkers of tryptophan metabolism. NIBS techniques reviewed were electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), and transcranial direct current stimulation (tDCS). Of the 564 search results, 65 studies were included with publications dating back to 1971 until 2022. The Robust Bayesian Meta-Analysis on clinical studies and qualitative analysis identified general null effects by NIBS on biomarkers of tryptophan metabolism, but moderate evidence for TMS effects on elevating serum serotonin levels. We cannot interpret this as evidence for or against the effects of NIBS on these biomarkers, as there exists several confounding methodological differences in this literature. Future controlled studies are needed to elucidate the effects of NIBS on biomarkers of tryptophan metabolism, an under-investigated question with substantial implications to clinical research and practice.
色氨酸代谢的犬尿氨酸和血清素途径的异常激活与许多神经精神疾病有关。同时，非侵入性脑刺激 (NIBS) 技术在神经精神疾病中显示出很高的治疗效果，并表明这种效果的基础是调节神经可塑性。因此，我们按照 PRISMA 声明进行了范围综述和荟萃分析，通过搜索 PubMed 和 Web of Science 数据库，寻找报告 NIBS 对色氨酸代谢生物标志物影响的临床前和临床研究。综述的 NIBS 技术包括电惊厥疗法 (ECT)、经颅磁刺激 (TMS) 和经颅直流电刺激 (tDCS)。在 564 个搜索结果中，有 65 项研究符合纳入标准，其出版物可追溯到 1971 年至 2022 年。临床研究的稳健贝叶斯荟萃分析和定性分析确定了 NIBS 对色氨酸代谢生物标志物的一般无效影响，但 TMS 对提高血清血清素水平有中度影响。我们不能将这解释为 NIBS 对这些生物标志物的影响的证据，因为在这一文献中存在着许多混杂的方法学差异。未来需要进行对照研究，以阐明 NIBS 对色氨酸代谢生物标志物的影响，这是一个研究不足的问题，对临床研究和实践具有重要意义。
