Roles of the Apolipoprotein E Gene and Its Polymorphisms in the Etiopathophysiology of Type 2 Diabetes Mellitus and Its Atherosclerotic Complication in Senegalese Females

Lipid metabolism disorders would be among the components responsible for the risk of the onset of T2DM and its vascular complications. Apolipoprotein E plays an important role in lipid metabolism. We studied the involvement of the APOE gene in the onset of T2DM and its vascular complications. Clinical and biochemical parameters were assessed in each participant. APOE genotypes were identified by PCR-RFLP. Arterial stiffness was studied using a pOpmetre® which evaluates the pulse wave velocity (ft-PWV). Endothelial dysfunction was studied using an EndoPAT2000® which measures endothelium-dependent vasodilation (RHI). In control subjects, the ε3 allele was associated with an increase in fasting blood glucose (r = 2.36, p = 0.018), and a decrease in LDL cholesterol levels (r = −2.17, p = 0.03), and ε4 was associated with an increase in total cholesterol (r = 2.59, p = 0.01), LDL cholesterol (r = 2.84, p = 0.004), and No-HDL cholesterol (r = 2.74, p = 0.006). In type 2 diabetes subjects, the ε2 was associated with a decrease in diastolic blood pressure (r = −2.25, p = 0.02). The ε3 was associated with a decrease in ft-PWV (r = −2.26, p = 0.024) while the ε4 was associated with an increase in ft-PWV (r = 2.52, p = 0.012). Carrying the ε2ε3 genotype would have in 99% a limited risk of developing T2DM, and in event of T2DM, only 1 to 2% would have a significant risk of developing atherosclerosis, which would be severe in 17%. Of the ε2ε4 genotype, 93% had a limited or even possible risk of developing T2DM, the remaining 7% had a very high risk of developing T2DM. Diabetics carrying ε2ε4 had in 7% very high risk of developing atherosclerosis. The latter had a 20% very high risk of being very severe. Subjects carrying the ε3ε4 genotype had a 67% possible or even probable risk of developing T2DM and in the event of diabetes, there was in 34% very high risk of developing atherosclerosis which will not have even the time to evolve towards severity. For subjects carrying the ε3ε3, the risk of developing T2DM and athérosclerosis was higher than that of the ε2ε3, and ε2ε4 genotypes but lower than that ε3ε4 genotype. The physio-pathological role of the APOE gene and the impacts of its polymorphisms are important in the onset and progression of type 2 diabetes mellitus.