Association of apoE gene polymorphisms with lipid metabolism in renal diseases

Background and Objectives: Apolipoprotein E (apoE) plays a central role in the metabolism and homeostasis of lipids. ApoE gene encodes three major isoforms: e2, e3 and e4 forming six phenotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4 . Disorders of the lipid metabolism and the homeostasis are frequently coexist in renal diseases. The association be- tween gene polymorphisms of apoE and lipid metabolism were not consistent. This meta-analysis was performed to assess the association between gene polymorphisms of apoE and lipid metabolism in renal diseases. Methods: A pre-defined literatures search and selection of eligible relevant investigations were performed to extract and collect data from electronic databases. Results: Sixteen articles were enrolled for the analysis of association between apoE gene polymorphisms and lipid metab- olism. Subjects with E3E4 had a higher total cholesterol (TC) than those with E3E3, and subjects with E2E3 had a lower TC than those with E3E3. Subjects with e2, e3 had a lower TC than those with e2, e3 or e4 , and subjects with e4 had a higher TC than those with e2, e3 . Subjects with E2E2, E2E3 or E4E4 had a higher triglyceride (TG) than those with E3E3. Subjects with e4 had a higher TG than those with e2, e3 . Subjects with e2, e3 had a higher level of TG than those with non-e2, e3 . Subjects with E3E4 had a slightly lower high-density lipoprotein (HDL) than those with E3E3. E3E4 appeared to be associated with lower levels of HDL. Subjects with E2E2, E2E3 had a notably lower low-density lipoprotein (LDL) than those with E3E3. Subjects with e2, e3 had a lower LDL than those with e2, e3 or e4 ApoE gene polymorphisms were not associated with very low-density lipoprotein, and lipoprotein (a) [Lp(a)]. Subjects with E2E3 or E2E4 had higher apoE levels than those with E3E3, and subjects with E4E4 had lower apoE levels than those with E3E3. Conclusion: ApoE gene polymorphisms are associated with the expression of TC, TG HDL, LDL, Lp(a) or apoE. Keywords: Apolipoprotein E (ApoE) ; gene polymorphism; total cholesterol (TC) ;triglyceride (TG), high-density lipopro- tein (HDL); low-density lipoprotein (LDL); very low-density lipoprotein (VLDL); lipoprotein (a) [Lp(a)] • Meta-analysis