İriz Ayşe, Şemsi Rabia, Eser Burcu, Arslan Burak, Dinçel Aylin Sepici
Department of Otorhinolaryngology (Ear-Nose-Throat), Gazi University Faculty of Medicine, Ankara, Turkey.
Department of Medical Biochemistry, Gazi University Faculty of Medicine, Ankara, Turkey.
Sleep Breath. 2021 Sep;25(3):1389-1398. doi: 10.1007/s11325-020-02250-7. Epub 2020 Nov 21.
The kynurenine (Kyn) pathway may play a role in certain physiological functions such as behavior, sleep, thermoregulation, and pregnancy. Tryptophan (Trp) is oxidized with tryptophan 2,3-dioxygenase and indolamine 2,3-dioxygenase (IDO). Under normal conditions, hepatic kynurenine is a transcription factor and IDO expression in healthy tissues is very low. The ratio of Kyn to Trp can be used as an indicator to assess IDO activity. This study aimed to determine the relationship between Kyn/Trp ratio and obstructive sleep apnea syndrome (OSAS) disease activity.
Study participants were categorized in 3 groups: Group 1 included patients with mild OSAS, Group 2, patients with moderate to severe OSAS, and Group 3, individuals considered normal to serve as controls. The demographic characteristics of the patients were recorded. Apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) measurements were performed by diagnostic polysomnography (PSG). Trp and Kyn levels were determined by HPLC-UV method.
Group 1 included 30 patients (18 men) with mild OSAS; Group 2 included 42 patients (31 men) with moderate to severe OSAS; and Group 3 included 25 controls (13 men). While there was no statistically significant difference between the levels of tryptophan and kynurenine in the groups, a significant difference was found between the Kyn/Trp ratios. A significant correlation was observed in individuals with a body mass index less than 25 with the Kyn/Trp ratio. In individuals with mild OSAS, a significant correlation was observed between ODI and BMI. In individuals with moderate to severe OSAS, there was a significant correlation between ODI, AHI, and BMI.
In this study, there was no relationship between OSAS disease severity and IDO activity as assessed by immunoreactivity via the Kyn/Trp pathway.
犬尿氨酸（Kyn）途径可能在某些生理功能中发挥作用，如行为、睡眠、体温调节和妊娠。色氨酸（Trp）通过色氨酸2,3-双加氧酶和吲哚胺2,3-双加氧酶（IDO）被氧化。在正常情况下，肝脏中的犬尿氨酸是一种转录因子，健康组织中IDO的表达非常低。Kyn与Trp的比值可作为评估IDO活性的指标。本研究旨在确定Kyn/Trp比值与阻塞性睡眠呼吸暂停综合征（OSAS）疾病活动之间的关系。
研究参与者分为3组：第1组包括轻度OSAS患者，第2组包括中度至重度OSAS患者，第3组为被认为正常的个体作为对照组。记录患者的人口统计学特征。通过诊断性多导睡眠图（PSG）进行呼吸暂停低通气指数（AHI）和氧饱和度下降指数（ODI）测量。采用高效液相色谱-紫外法测定Trp和Kyn水平。
第1组包括30例轻度OSAS患者（18例男性）；第2组包括42例中度至重度OSAS患者（31例男性）；第3组包括25例对照组（13例男性）。虽然各组之间色氨酸和犬尿氨酸水平无统计学显著差异，但Kyn/Trp比值存在显著差异。体重指数小于25的个体中，Kyn/Trp比值存在显著相关性。在轻度OSAS个体中，ODI与BMI之间存在显著相关性。在中度至重度OSAS个体中，ODI、AHI与BMI之间存在显著相关性。
在本研究中，通过Kyn/Trp途径免疫反应评估的OSAS疾病严重程度与IDO活性之间没有关系。
