Remnant-like particles (RLP) from NIDDM patients with apolipoprotein E3/3 phenotype stimulate cholesteryl ester synthesis in human monocyte-derived macrophages.

Abstract

We tested the ability of remnant-like particles (RLP) from NIDDM patients to stimulate cholesteryl ester synthesis in human monocyte-derived macrophages. Six NIDDM patients were studied together with 7 non-diabetic subjects. All had apolipoprotein (apo) E3/3 phenotype. RLP were isolated using an immunoaffinity gel mixture of anti apo B-100 and anti apo A-1 monoclonal antibodies coupled to Sepharose 4B. Plasma levels of triglyceride, total cholesterol (chol) and high density lipoprotein-chol were not statistically different, but plasma levels of RLP-chol were significantly (p < 0.05) higher in NIDDM patients (10.5 +/- 2.2 mg/dl) than in non-diabetic controls (5.0 +/- 1.7 mg/dl). The effects of RLP from NIDDM patients on macrophage cholesteryl ester synthesis were estimated. 14C-oleate incorporation into cholesteryl esters in macrophages was significantly (p < 0.01) higher in NIDDM patients with apo E3/3 (0.326 +/- 0.037 nmole/mg cell protein) than in non-diabetic controls with apo E3/3 (0.181 +/- 0.011 nmole/ mg cell protein). It is suggested that RLP from NIDDM play a role in the accumulation of cholesteryl esters and are one of the risk factors for the acceleration of atherosclerosis in NIDDM.