Triglyceride-rich lipoproteins in chronic kidney disease patients undergoing maintenance haemodialysis treatment

Abstract

Plasma triglyceride (TG) levels were reported to be high in chronic kidney disease (CKD) patients undergoing haemodialysis (HD) treatment. One of the atherogenic causes of hypertriglyceridemia is the increase in TG-rich lipoprotein remnants, which are equivalent to remnant-like particle cholesterol (RLP-C). Here, we compared the plasma levels of TG, a representative indicator of TG-rich lipoproteins and RLP-C, as well as the TG/RLP-C ratio between CKD patients undergoing HD and controls, in an effort to elucidate the atherogenicity of TG-rich lipoproteins in CKD patients on HD. Plasma lipid and apo(lipo)protein levels and the TG/RLP-C ratio were compared between 49 CKD patients undergoing HD and 627 controls. Blood sampling for lipid and apoprotein analysis was performed in a 12-h fasting state. Controls were divided into four subgroups according to TG level (from highest to lowest). RLP-C and apo(lipo)proteins were measured using the immunoprecipitation method and turbidimetric immunoassay, respectively. In addition, a comparison between HD patients and age-, gender-, and plasma TG level-matched controls was performed. Plasma TG levels were 107 ± 70 (mean ± SD) mg/dl in HD patients and 115 ± 72 mg/dl in controls. Plasma RLP-C levels were 6.7 ± 4.5 mg/dl in HD patients and 4.6 ± 3.5 mg/dl in the controls (p < 0.0001). RLP-C levels decreased in descending order from the highest to the lowest TG group in controls. RLP-C levels were higher in HD patients than in controls with plasma TG levels of < 150 mg/dl (p < 0.0001). TG/RLP-C ratios were 19.0 ± 12.0 in HD patients and 25.9 ± 9.5 in controls (p < 0.0001). This ratio was significantly lower in HD patients than in all four TG subgroups. The comparison between HD patients and age-, gender-, plasma TG-matched controls revealed identical results. Plasma RLP-C levels were high, and the TG/RLP-C ratio was low in CKD patients undergoing HD treatment. These findings indicate that total plasma TG-rich lipoprotein levels were not increased, but the distribution of plasma TG-rich lipoproteins were skewed towards remnant fractions in CKD patients undergoing HD treatment; these plasma TG-rich lipoproteins appear to be more atherogenic than those in controls.