APOL1 Genetic Variants Are Associated with Serum-Oxidized Low-Density Lipoprotein Levels and Subclinical Atherosclerosis in South African CKD Patients.

INTRODUCTION

Apolipoprotein L1 (APOL1) plays an important role in cholesterol metabolism and attenuation of low-density lipoprotein (LDL) oxidation. While protecting against Trypanosoma brucei rhodesiense infection, APOL1 risk alleles confer greater risk for CKD and cardiovascular disease among patients of African descent.

OBJECTIVES

We investigated whether APOL1 risk variants are associated with atherosclerosis and oxidized LDL (OxLDL) levels among black South African CKD patients.

METHODS

A cross-sectional study of 120 adult CKD patients and 40 controls was undertaken. DNA samples of participants were genotyped for APOL1 G1 and G2 variants. High-sensitivity C-reactive protein, serum lipids, and OxLDL levels were measured, and carotid doppler ultrasonography was performed on all participants.

RESULTS

APOL1 alleles rs73885319, rs60910145, and rs71785313 had minor allele frequencies of 9.2, 8.8, and 17.5%, respectively, in the patients, and 8.8, 8.8, and 13.8%, respectively, in the controls. Of the 9 patients with 2 APOL1 risk alleles, 77.8% were compound G1/G2 heterozygotes and 22.2% were G2 homozygotes. Carriers of at least 1 APOL1 risk allele had a 3-fold increased risk of subclinical atherosclerosis (odds ratio 3.19; 95% confidence interval: 1.64-6.19; p = 0.01) compared to individuals with no risk alleles. Patients with 1 or 2 APOL1 risk alleles showed a significant increase in OxLDL levels when compared with those without the APOL1 risk allele.

CONCLUSION

These findings suggest an increased risk for atherosclerosis in carriers of a single APOL1 risk variant, and the presence of APOL1 risk variants was associated with increased serum OxLDL levels in black South African CKD patients.