遗忘型轻度认知功能损害的认知特征、血清脑源性神经营养因子水平及其基因的Val66Met多态性

Cognitive function,serum BDNF levels and BDNF gene Val66Met polymorphism in amnestic mild cognitive impairment

目的:探讨血清脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)水平及其基因的Val66Met多态性与遗忘型轻度认知功能损害(amnestic mild cognitive impairment,aMCI)及其认知特征的关系。方法:应用多维度神经心理测试评估99例aMCI患者(aMCI组)和99例正常对照者(正常对照组)的神经认知功能;采用酶联免疫吸附试验测定血清BDNF水平,聚合酶链反应-限制性片段长度多态性分析BDNF基因的Val66Met多态性。结果:aMCI组的各项神经认知测试成绩均显著差于正常对照组(P<0.001),尤以反映词语性情节记忆的听觉词语记忆测试(auditory verbal memory test,AVMT)的延迟回忆项受损最明显;aMCI组血清BDNF水平(中位数为4.37μg/L)低于正常对照组(中位数为4.98μg/L)(z=-2.449,P=0.014),且与AVMT的延迟回忆呈显著正相关(r=0.264,P=0.008);aMCI组和正常对照组间BDNF基因的Val66Met基因型和等位基因频率差异无统计学意义(P>0.05),aMCI组BDNF基因的Val66Met基因型亚组间各神经认知测试成绩和血清BDNF水平差异无统计学意义(均P>0.05)。结论:在aMCI中,降低的血清BDNF水平表明神经营养缺乏,这可能在其病理生理过程中发挥作用;BDNF基因Val66Met多态性可能不是aMCI主要的遗传因素。

Objective To investigate the relationship between serum brain-derived neurotrophic factor, concentrations and BDNF gene Val66Met polymorphism and amnestic mild cognitive impairment （ aMCI ） , and neuropsychological characteristics. Methods Ninety-nine aMCI patients and 99 matched normal controls were recruited for the study. Multi-dimension neuropsychologic tests were used to extensively assess the cognitive function, an enzyme-linked immunosorbent assay was applied to measure serum BDNF concentrations, and polymerase chain reaction-restriction fragment length polymorphism was used to analyse BDNF gene Val66Met polymorphism in the subjects. Results The scores of neuropsychologic tests in aMCI patients were significantly lower than those in the normal controis （ all P 〈 0.001 ） , with the largest impairment on delayed recall of the auditory verbal memory test （ AVMT ） which reflect verbal episodic memory. The serum concentrations of BDNF in aMCI patients （median： 4.37μg/L） were significantly lower than those of the normal controls （median： 4.98 μg/L） （z = -2. 449, P =0.014）. There was positive correlation between the serum concentrations of BDNF and the scores on delayed recall of AVMT （ r = 0. 264, P = 0. 008 ）. No significant differences were found for the genotype and allele distribution of BDNF Val66Met polymorphism between aMCI patients and the normal controls. BDNF Val66Met polymorphism was not associated with serum BDNF concentrations and cognitive assessment scores in aMCI patients （ P 〉 0.05 ）. Conclusion aMCI is characterized by episodic memory impairment. Decreased BDNF concentrations may play a role in the pathophysiology of aMCI, and BDNF gene Val66Met polymorphism may not be an important genetic factor in susceptibility to aMCI.