Influence of the polymorphism of apolipoprotein E in cerebral vascular disease

The genetic heterogeneity of apolipoprotein E (apo E) has been associated with lipid profile and atherothrombotic stroke, however this association remains inconclusive.

To evaluate the relationship between the isoforms of apo E and atherothrombotic stroke, by ascertaining the frequency of its alleles and genotypes associated with the lipid profile in patients with stroke.

A total of 207 individuals were divided into two groups, consisting of 107 patients with stroke and 100 individuals without clinical symptoms of the disease. Blood samples were taken from patients and controls for molecular investigation of the apo E (epsilon2, epsilon3 and epsilon4 alleles) for the analysis of the lipid profile.

The epsilon3 allele was the most common and its prevalence was significantly higher in patients (0.93) compared to the controls (0.86; p=0.024). The epsilon2 allele was rarely seen specifically in patients (0.02 versus 0.05 in controls, p=0.191). The epsilon4 allele was not associated with stroke showing a reduced frequency in patients (0.05) when compared to controls (0.09; p=0.011). Although higher average levels of lipid profile were found in patients when compared to controls, with statistical significance for the values of total cholesterol (TC) (203.6 mg/dL +/- 57.98 and 181.9 mg/dL +/- 68.47 respectively; p=0.003) and low-density lipoprotein cholesterol (LDLc) (131.4mg/dL +/- 52.60 and 116 mg/dL +/- 56.38, respectively; p=0.014), these were independent of the presence of the epsilon4 allele. In control group the higher TC and LDLc values occurred in the absence of the epsilon4 allele, confirming the conflicting effect of the alleles of apo E on the plasmatic lipids and atherothrombotic stroke.

The isoforms of apo E cannot be regarded as an isolated risk factor for stroke and do not show association with lipid profile in this study.