English abstract
Background: Ischemic stroke is a health concern worldwide. It has been suggested that ischemic stroke is a multifactorial disease of various etiologies involving both
genetic factors, with growing evidence that suggests synergistic effect of the two. Polymorphism of apolipoprotein E (APOE) gene, which is associated with lipid metabolism, has been the focus of numerous studies as a potential risk factor for ischemic stroke,
Objectives: This is the first case-control study to assess and compare the distribution of Apo E polymorphism among Omani patients with and without ischemic stroke, and to compare lipid profile among the various APOE genotypes as well as between the two study groups.
Method: A total of 100 cases of large artery atherothrombotic and small vessel occlusion ischemic stroke were recruited from Sultan Qaboos University Hospital (SQUH). A similar number of age-matched controls were recruited from the same hospital based on some inclusion and exclusion criteria. Fasting blood samples were collected for lipid profile measurement using the standard methods and for genomic DNA extraction. APOE genotyping was performed by real-time PCR using TaqMan SNP Genotyping Assay.
Results: There was no significant difference in APOE allele frequencies between ischemic stroke cases (Apo 82: 0.03; Apo $3: 0.88; Apo £4: 0.09) and controls (Apo £2: 0.05; Apo £3: 0.87; Apo 84: 0.08). Apo 84-containing genotypes were higher among cases than controls (18% vs 13%), however, that was not sufficient for significant association (OR=1.47, 95%CI: 0.67-3.19). In addition, there was no significant difference in lipid profile among cases carrying different APOE alleles. Similarly there was no significant difference in lipid profile among controls carrying different APOE alleles. However, among the different lipid parameters, significant difference was found between cases and controls in triglycerides and HDL levels. Cases had higher triglycerides (p value: 0.001) and lower HDL (p-value: 0.01) than controls. In addition, that difference became highly significant when atherogenic index of plasma (AIP) was computed (p value: <0.001) even after gender and genotype stratifications.
Conclusion: APOE gene polymorphism neither has been found significantly associated with ischemic stroke nor with lipid profile in this study. However, AIP a previously established marker for vascular diseases was significantly different between the two study groups.
