Very Small Apolipoprotein A-I-containing Particles from Human Plasma: Isolation and Quantification by High-Performance Size-Exclusion Chromatography

• Published in: Clinical chemistry (Baltimore, Md.) Md.), 2000-02, Vol.46 (2), p.207-223
• Main Authors: Nanjee, M. Nazeem, Brinton, Eliot A
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Analytical, structural and metabolic biochemistry; Apolipoprotein A-I - blood; Apolipoprotein A-I - chemistry; Apolipoprotein A-I - isolation & purification; Biological and medical sciences; Chromatography, Gel; Female; Fundamental and applied biological sciences. Psychology; Humans; Lipoproteins, myelin; Male; Middle Aged; Particle Size; Proteins; Reproducibility of Results
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/46.2.207

Very small apolipoprotein (apo) A-I-containing lipoprotein (Sm LpA-I) particles with pre-beta electrophoretic mobility may play key roles as "nascent" and/or "senescent" HDL; however, methods for their isolation are difficult and often semiquantitative. We developed a preparative method for separating Sm LpA-I particles from human plasma by high-performance size-exclusion chromatography (HP-SEC), using two gel permeation columns (Superdex 200 and Superdex 75) in series and measuring apo A-I content in column fractions in 30 subjects with HDL-cholesterol (HDL-C) concentrations of 0.4-3.83 mmol/L. Three major sizes of apo A-I-containing particles were detected: an approximately 15-nm diameter ( approximately 700 kDa) species; a 7. 5-12 nm (100-450 kDa) species; and a 5.8-6.3 nm species (40-60 kDa, Sm LpA-I particles), containing 0.2-3%, 80-96%, and 2-15% of plasma total apo A-I, respectively. Two subjects with severe HDL deficiency had increased relative apo A-I content in Sm LpA-I: 25% and 37%, respectively. The percentage of apo A-I in Sm LpA-I correlated positively with fasting plasma triglyceride concentrations (r = 0. 581; P