Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Medical Laboratory Technology Department, College of Medical Technology, The Islamic University, Najaf, 31001, Iraq.
BMC Infect Dis. 2022 Jul 15;22(1):615. doi: 10.1186/s12879-022-07582-1.
Coronavirus disease 2019 (COVID-19) is accompanied by activated immune-inflammatory pathways and oxidative stress, which both induce indoleamine-2,3-dioxygenase (IDO), a key enzyme of the tryptophan (TRP) catabolite (TRYCAT) pathway. The aim of this study was to systematically review and meta-analyze the status of the TRYCAT pathway, including the levels of TRP and kynurenine (KYN) and the activity of IDO, as measured by the ratio of KYN/TRP.
This systematic review searched PubMed, Google Scholar, and Web of Sciences and included 14 articles that compared TRP and tryptophan catabolites (TRYCATs) in COVID-19 patients versus non-COVID-19 controls, as well as severe/critical versus mild/moderate COVID-19. The analysis was done on a total of 1269 people, including 794 COVID-19 patients and 475 controls.
The results show a significant (p < 0.0001) increase in the KYN/TRP ratio (standardized mean difference, SMD = 1.099, 95% confidence interval, CI: 0.714; 1.484) and KYN (SMD = 1.123, 95% CI: 0.730; 1.516) and significantly lower TRP (SMD = - 1.002, 95%CI: - 1.738; - 0.266) in COVID-19 versus controls. The KYN/TRP ratio (SMD = 0.945, 95%CI: 0.629; 1.262) and KYN (SMD = 0.806, 95%CI: 0.462; 1.149) were also significantly (p < 0.0001) higher and TRP lower (SMD = - 0.909, 95% CI: - 1.569; - 0.249) in severe/critical versus mild/moderate COVID-19. No significant difference was detected in kynurenic acid (KA) and the KA/KYN ratio between COVID-19 patients and controls.
Our results indicate increased activity of the IDO enzyme in COVID-19 and severe/critical patients. The TRYCAT pathway is implicated in the pathophysiology and progression of COVID-19 and may signal a worsening outcome of the disease.
2019 年冠状病毒病（COVID-19）伴有激活的免疫炎症途径和氧化应激，这两者都诱导色氨酸（TRP）分解代谢物（TRYCAT）途径的关键酶吲哚胺 2,3-双加氧酶（IDO）。本研究的目的是系统地回顾和荟萃分析 TRYCAT 途径的状态，包括色氨酸（TRP）和犬尿氨酸（KYN）的水平以及 IDO 的活性，通过 KYN/TRP 的比值来衡量。
本系统评价检索了 PubMed、Google Scholar 和 Web of Sciences，并纳入了 14 篇比较 COVID-19 患者与非 COVID-19 对照以及重症/危重症 COVID-19 与轻症/中度 COVID-19 患者 TRP 和色氨酸分解产物（TRYCATs）的文章。分析共涉及 1269 人，包括 794 例 COVID-19 患者和 475 例对照。
结果显示，COVID-19 患者与对照相比，KYN/TRP 比值（标准化均数差，SMD=1.099，95%置信区间，CI：0.714；1.484）、KYN（SMD=1.123，95%CI：0.730；1.516）显著升高（p<0.0001），而 TRP 显著降低（SMD=-1.002，95%CI：-1.738；-0.266）。COVID-19 患者与对照相比，KYN/TRP 比值（SMD=0.945，95%CI：0.629；1.262）和 KYN（SMD=0.806，95%CI：0.462；1.149）也显著升高（p<0.0001），而 TRP 显著降低（SMD=-0.909，95%CI：-1.569；-0.249）。COVID-19 患者与对照之间的犬尿氨酸酸（KA）和 KA/KYN 比值无显著差异。
我们的结果表明 IDO 酶在 COVID-19 和重症/危重症患者中的活性增加。TRYCAT 途径与 COVID-19 的病理生理学和进展有关，可能预示着疾病的预后恶化。
