Malondialdehyde-modified LDL-related variables are associated with diabetic kidney disease in type 2 diabetes

Abstract Background and aims Oxidized low-density lipoprotein (oxLDL) causes the development of atherosclerosis and kidney injury. Although circulating oxLDL levels were reportedly increased in type 2 diabetic patients with macroalbuminuria, it remains unclear whether albuminuria or the reduced glomerular filtration rate (GFR) is independently associated with the circulating oxLDL level. This study aimed to elucidate the association between the stage of diabetic nephropathy and serum malondialdehyde-modified LDL (MDA-LDL) and the ratio of MDA-LDL to LDL-cholesterol (MDA-LDL/LDL). Methods and results This retroactive cross-sectional study used data from 402 patients with type 2 diabetes. Patients undergoing hemodialysis were excluded. Serum MDA-LDL levels were significantly increased with increases in severity of albuminuria (103 ± 44 U/L, 109 ± 54 U/L, and 135 ± 72 U/L for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.020) but not according to the estimated GFR (eGFR). An increased MDA-LDL/LDL ratio was significantly associated with both increased albuminuria (35 ± 13, 37 ± 14, and 40 ± 15 for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.003) and reduced eGFR (34 ± 13, 36 ± 13, 38 ± 12, and 51 ± 28 for grade 1, 2, 3 and 4, respectively; P for trend = 0.002). Multiple linear regression analysis showed that neither the albumin excretion rate nor eGFR but ln-transformed triglycerides and LDL-C levels were independent determinants of both serum MDA-LDL levels and MDA-LDL/LDL ratios. Conclusion Serum MDA-LDL levels and MDA-LDL/LDL ratios were increased in those with dyslipidemia associated with diabetic kidney disease.