Zitnanová Ingrid, Korytár Peter, Aruoma Okezie I, Sustrová Mária, Garaiová Iveta, Muchová Jana, Kalnovicová Terézia, Pueschel Siegfried, Duracková Zdenka
Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, Sasinkova 2, 813 72 Bratislava, Slovak Republic.
Clin Chim Acta. 2004 Mar;341(1-2):139-46. doi: 10.1016/j.cccn.2003.11.020.
Down syndrome (DS) is a chromosomal abnormality (trisomy 21) leading to mental retardation, to the characteristic change of individual's phenotype and to the pathological features of Alzheimer disease. Patients with DS have elevated ratio of superoxide dismutase to (catalase plus glutathione peroxidase) with respect to controls in all age categories suggesting that oxidative imbalance contributes to the clinical manifestation of accelerated aging.
We report that persons with DS have elevated uric acid levels compared with controls, 348.56+/-22.78 versus 284.00+/-20.86 micromol/l (p=0.018). The levels of hypoxanthine and xanthine in DS children (6.35+/-0.31 and 1.02+/-0.23 micromol/l) were significantly lower than in controls (7.83+/-0.59 and 2.43+/-0.66 micromol/l). This result suggests increased conversion of hypoxanthine and xanthine to uric acid with subsequent free radical-dependent oxidation of uric acid to allantoin, mechanisms potentiated by the oxidative stress in DS. Allantoin is a nonenzymatic oxidative product of uric acid in human. In DS individuals, the levels of allantoin were significantly higher than those in healthy controls (18.58+/-2.27 and 14.07+/-1.07 micromol/l, respectively, p=0.03).
Our data supported the presumption of increased oxidative stress in DS.
唐氏综合征（DS）是一种染色体异常疾病（21三体综合征），可导致智力发育迟缓、个体表型特征改变以及阿尔茨海默病的病理特征。与各年龄组的对照组相比，DS患者超氧化物歧化酶与（过氧化氢酶加谷胱甘肽过氧化物酶）的比值升高，这表明氧化失衡导致了加速衰老的临床表现。
我们报告，与对照组相比，DS患者的尿酸水平升高，分别为348.56±22.78与284.00±20.86微摩尔/升（p = 0.018）。DS儿童的次黄嘌呤和黄嘌呤水平（分别为6.35±0.31和1.02±0.23微摩尔/升）显著低于对照组（分别为7.83±0.59和2.43±0.66微摩尔/升）。这一结果表明次黄嘌呤和黄嘌呤向尿酸的转化增加，随后尿酸在自由基作用下氧化为尿囊素，DS中的氧化应激增强了这些机制。尿囊素是人体内尿酸的非酶促氧化产物。在DS个体中，尿囊素水平显著高于健康对照组（分别为18.58±2.27和14.07±1.07微摩尔/升，p = 0.03）。
我们的数据支持了DS中氧化应激增加的推测。
