老年代谢综合征与非酒精性脂肪肝患者载脂蛋白E基因多态性检测的意义

目的探讨老年代谢综合征(MS)与非酒精性脂肪肝(NAFL)的载脂蛋白E(apo E)基因多态性之间的关系及意义。方法本研究以60岁以上农村老年健康体检者筛检出的NAFL 126例、NAFL MS 105例、非脂肪肝125例及体检正常老年者95名为研究对象,其血液应用特异引物扩增人DNA apo E基因265 bp片段和特异探针杂交后,通过分析熔解曲线检测基因突变点及多态性。酶联免疫吸附试验(ELISA)检测apo E、apo E4基因浓度,并进行血脂、血糖、尿素、酶类、体质指数和血压分析。结果NAFL组和NAFL MS组以杂合子E2/3、E3/4基因型频率最高,分布频率分别为E2/3(36.5%、28.1%)、E3/4(27.2%、32.6%)、E3/3(32.3%、34.0%)、E2/4(2.4%、1.5%)、E4/4(0.8%、3.8%)、E2/2(0.8%、0.0%);NAFL MS组E4/4频率显著高于对照组,apoE基因总浓度明显升高(P<0.05),E2/3、E3/4 2组血脂等生化指标和体质指数及血压均有不同程度增高,差异有显著性(P<0.05)。结论apo E基因多态性与老年NAFL和MS存在相关性,携带E3/4、E2/3型或E4/4型的个体存在,提示在决定个体老年MS合并NAFL遗传易感性方面有重要作用,apo E基因112位和158位的氨基酸残基发生相应的变化可引起不同程度的脂质代谢障碍。

Significance of apo E gene polymorphism in the elder's metabolic syndrome and nonalcoholic fatty liver

Objective To investigate the relevance of the elder's metabolic syndrome(MS) and the apolipoprotein E(apo E) gene polymorphism in nonalcoholic fatty liver(NAFL). Methods 126 cases NAFL,105 cases NAFL MS,125 cases non-fatty liver and 95 healthy persons aged more than 60 years were selected from health examination.The 265 bp fragment of apo E gene was genotyped by polymerase chain realtion(PCR) and then hybridized with the species-specific probe,melting curve was used to measure the genotyping of apo E point mutations and gene polymorphism.The expression of apo E and apo E4 was measured by enzyme-linked immunosorbent assay(ELISA),and the serum lipid levels,glucose,urea nitrogen,enzyme,body mass index and blood pressure were determined. Results The most common allele was E2/3 in NAFL and NAFL MS,the frequencies were:E2/3(36.5%,28.1%),E3/4(27.2%,(32.6%)),E3/3(32.3%,34.0%),E2/4(2.4%,1.5%),E4/4(0.8%,3.8%),E2/2(0.8%,0.0%);E4/4 in NAFL MS was higher than that of control group.The expression of apo E was up-regulated(P<0.05).A slight increase of blood lipid,body mass index and blood pressure were observed,the difference was significant(P<0.05). Conclusions There is positive relationship between the elder's MS and NAFL in apo E gene polymorphism,E3/4,E2/3 or E4/4 have an important role in the elder's MS with NAFL on genetic susceptibility.The amino acid residue changes of apo E point mutations 112,158 could cause metabolism disturbane.