Department of Anaesthesiology and Intensive Care Medicine, University Hospital Ostrava, 708 52 Ostrava, Czech Republic.
Institute of Physiology and Pathophysiology, Faculty of Medicine, University of Ostrava, 703 00 Ostrava, Czech Republic.
Int J Mol Sci. 2021 Oct 28;22(21):11714. doi: 10.3390/ijms222111714.
Tryptophan is an essential amino acid whose metabolites play key roles in diverse physiological processes. Due to low reserves in the body, especially under various catabolic conditions, tryptophan deficiency manifests itself rapidly, and both the serotonin and kynurenine pathways of metabolism are clinically significant in critically ill patients. In this review, we highlight these pathways as sources of serotonin and melatonin, which then regulate neurotransmission, influence circadian rhythm, cognitive functions, and the development of delirium. Kynurenines serve important signaling functions in inter-organ communication and modulate endogenous inflammation. Increased plasma kynurenine levels and kynurenine-tryptophan ratios are early indicators for the development of sepsis. They also influence the regulation of skeletal muscle mass and thereby the development of polyneuromyopathy in critically ill patients. The modulation of tryptophan metabolism could help prevent and treat age-related disease with low grade chronic inflammation as well as post intensive care syndrome in all its varied manifestations: cognitive decline (including delirium or dementia), physical impairment (catabolism, protein breakdown, loss of muscle mass and tone), and mental impairment (depression, anxiety or post-traumatic stress disorder).
色氨酸是一种必需氨基酸，其代谢产物在多种生理过程中发挥关键作用。由于体内储备量低，尤其是在各种分解代谢状态下，色氨酸缺乏会迅速表现出来，代谢的 5-羟色氨酸和犬尿氨酸途径在危重病患者中具有重要的临床意义。在这篇综述中，我们强调了这些途径是 5-羟色氨酸和褪黑素的来源，它们调节神经递质传递、影响昼夜节律、认知功能和谵妄的发展。犬尿氨酸在器官间的通讯中具有重要的信号功能，并调节内源性炎症。血浆犬尿氨酸水平和犬尿氨酸-色氨酸比值升高是脓毒症发展的早期指标。它们还影响骨骼肌质量的调节，从而导致危重病患者多发性神经病的发生。色氨酸代谢的调节可能有助于预防和治疗与低度慢性炎症相关的年龄相关性疾病以及各种表现形式的重症监护后综合征：认知功能下降（包括谵妄或痴呆）、身体功能障碍（分解代谢、蛋白质分解、肌肉质量和张力丧失）以及精神障碍（抑郁、焦虑或创伤后应激障碍）。
