Kidney function, cholesterol absorption and remnant lipoprotein accumulation in patients with diabetes mellitus

Remnant lipoproteins are atherogenic and increased in patients with type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD) and other conditions. Thus far, information is limited regarding the synthesis and absorption of cholesterol in CKD patients and a possible link to the remnant levels. We examined possible alterations in serum markers of cholesterol synthesis and absorption and their potential associations with remnant lipoproteins in patients with CKD.

The subjects included 146 consecutive patients with T2DM in various stages of CKD. We measured the levels of remnant lipoprotein cholesterol (RemL-C), lathosterol (a cholesterol synthesis marker) and campesterol (a cholesterol absorption marker). The urinary albumin to creatinine ratio (U-ACR) and estimated glomerular filtration rate (eGFR) were used to describe the degree of CKD.

The median (interquartile range) levels of RemL-C, lathosterol and campesterol were 14.5 (11.5-23.4) mg/dL, 2.1 (1.7-2.9) μg/mL and 2.3 (1.7-3.0) μg/mL, respectively. The RemL-C level was positively correlated with the U-ACR and inversely correlated with the eGFR. The RemL-C level was positively correlated with both the lathosterol and campesterol levels. The lathosterol level was not significantly correlated with the U-ACR, although it was positively correlated with the eGFR. In contrast, the campesterol level was positively correlated with the ACR and inversely with the eGFR. In the multiple regression analysis, both lathosterol and campesterol were positively associated with the RemL-C level, independent of the U-ACR, eGFR and other variables.

The serum campesterol concentrations are higher in patients with a greater degree of albuminuria and a lower renal funtion. In this study, the markers of cholesterol absorption and synthesis were independent determinants of the RemL-C level. Increased intestinal cholesterol absorption may be an additional mechanism for remnant accumulation in T2DM patients with CKD.