阻塞性睡眠呼吸暂停综合征患者的认知障碍与胰岛素样生长因子—I间的关系

目的探讨阻塞性睡眠呼吸暂停综合征患者(OSAS)认知障碍的生化机制.方法对OSAS组36例,对照组18例进行睡眠多导仪和神经心理测验量表检查,用放射免疫方法检测血清胰岛素样生长因子1(IGF-I)水平,观察患者血清IGF-I变化,并比较它与认知功能、夜间低氧和睡眠结构紊乱间的关系. 结果 OSAS患者视觉再生(用于检测短时记忆能力)和数字符号(用于检测一般学习能力)两项神经心理测验分数明显低于对照组(视觉再生患者为8.4±2.7; 对照为11.6±1.4; P<0.01; 数字符号患者为36.9±8.3; 对照为47.8±6.8, P<0.01),血清IGF-I水平显著降低(患者为127.2±87.0; 对照为194.0±77.3; P<0.05),且与视觉再生(r=0.381,P<0.05)和数字符号(r=0.330, P<0.05)两项受损神经心理测验分数呈正相关,与最低血氧饱和度(r=0.371, P<0.05)、平均血氧饱和度(r=0.333, P<0.05)和REM睡眠长短(r=0.598, P<0.01)呈正相关.结论 OSAS患者短时记忆能力和一般学习能力受损,血清IGF-I水平降低,且可能是其认知功能障碍的生化机制之一.夜间低氧和REM期睡眠剥夺可能是导致血清IGF-I降低的原因.

Insulin-like growth factor-I and cognitive function in patients with obstructive sleep apnea syndrome

OBJECTIVE: To explore the possible biochemical mechanism of cognitive impairment in patients with obstructive sleep apnea syndrome (OSAS). METHODS: Polysomnography was administered to thirty-six patients with OSAS and eighteen education and BMI-matched controls, all males aged 40 approximately 49 for 8.5 hours at night. Early next morning blood was drawn and serum insulin-like growth factor-I (IGF-I) was determined by immunoradiometric assay. Then neuropsychological tests of visual regeneration, digital symbol, comprehensive memory and digital span were conducted. RESULTS: The quality of sleep in the patients with OSAS was significantly worse than that of the controls. The score of visual regeneration in the patients with OSAS was 8.4 +/- 2.7, significantly lower than that in control group (11.6 +/- 1.4, P < 0.01). The score of digital symbol in patients with OSAS was 36.92 +/- 8.31, significantly lower than that in the controls (47.8 +/- 6.8, P < 0.01). The serum IGF-I level of the patients with OSAS was: 127.2 +/- 87.0 ng/ml, significantly lower than that of the controls (194.03 ng/ml +/- 77.31 ng/ml, P < 0.05). The IGF-I level was significantly positively correlated with the scores of visual regeneration test (r = 0.381, P < 0.05) and digital symbol test (r = 0.330, P < 0.05), lowest SaO(2) (r = 0.371, P < 0.05), mean SaO(2) (r = 0.333, P < 0.05) and REM sleep duration (r = 0.598, P < 0.01). CONCLUSION: Decrease of serum IGF-I level may play a role in the cognitive impairment in patients with OSAS. Nocturnal hypoxemia and REM sleep deprivation may be the reason of the decrease of the serum IGF-I level in patients with OSAS.