Relationship Between Apolipoprotein E Polymorphism, Cerebrovascular Disease And Vascular Dementia

[Background] ApoE is a plasma protein that plays an important role in the metabolism of cholesterol and other serum lipids. It is an important determinant of risk for the development of atherosclerosis. In addition to this effect, it is proposed that one of the major functions of ApoE is to mediate neuronal repair, remodeling and protection. Although the e 4 allele has been found to be consistently associated with increased risk of AD, the relationship between ApoE e 4 allele, cerebrovascular disease and VD is controversial.[ Objective ] To study the relationship between apolipoprotein E polymorphism, cerebrovascular disease and vascular dementia, to detect the possible roles of ApoE in pathogenesis of these disorders and the relationship between ApoE alleles and serum lipid levels, and to investigate risk factors for vascular dementia.[ Methods 1 This was a hospital-based case-control study. Vascular dementia was diagnosed according to NINDS-AIREN criteria. The distribution of allelic and genotypic frequencies of ApoE was analyzed by PCR-RELP technique in VD group (51 cases), CI group (115 cases), ICH group (50 cases) and age-and sex-matched control group (120 cases). Meanwhile the serum levels of lipids and lipoprotein were measured. Risk factors for VD and CI were determined by using multiple logistic regression analysis.[Results] 1. Overall, patients with VD (11.8%) and CI (10%) had a higher ApoE e 4 allele frequency than controls (4.6%). Among patients with cerebral infarction, atherothrombosis and cardioembolism had a higher ApoE e 4 allele frequency than lacunar infarction. Risks associated with ApoE e 4 were elevated regardless of age. There was no difference in ApoE ?4 allele frequency between ICH and controls. 2. As compared with ApoE e 3, e 4 allele was associated withincreased serum level of TG and ?2 allele was associated with decreased serum levels of TG and LDL in controls. There were significant dyslipidemia associated with ApoE allele in CI and VD group. 3. Risk factors for VD were E 4 allele carrier (OR=3.0294), hypertension (OR= 5.0926) and TC (OR= 1.6711) compared with healthy controls, and more cerebral lesions (OR= 1.4223), left hemispheric stoke location (OR=8.7761) compared with stroke without dementia patients.[Conclusions] 1. ApoE e 4 allele is a genetic susceptible factor for VD and CI. 2. ApoE plays a key role in the metabolism of cholesterol and other serum lipids. The effect of ApoE on CI and VD may be mediated through dyslipidemia and atherogenesis through its effect on cholesterol and triglyceride metabolism. 3. Significant risk factors for VD were e 4 allele, hypertension, TC, more cerebral lesions and left hemispheric stoke location.