Journal of Proteomics & Bioinformatics
Open Access

Abstract

Apolipoprotein(a) Size and Lipoprotein(a) Concentrations in Patients with Good and Poor Coronary Collateral Flow - an Interrelation Discovered by Proteomic Screening of Pooled Plasma Samples

Daniel Stalder, Trinh Cung, Steffen Gloekler, Pascal Meier, Evelyn Schlappritzi, André Haeberli, Santica Marcovina, Christian Seiler and Manfred Heller

We discovered and validated medium sized apolipoprotein (a) as a marker for good myocardial collaterization. A total of 80 subjects were investigated in two serial studies: a discovery study (n=14) applying a pooling strategy to a gel and label free proteomics platform followed by a validation study (n=80) measuring apolipoprotein(a) isoforms and concentration in individual subjects. Degree of myocardial collaterization as well as apolipoprotein(a) concentration and isoform determination were performed by state-of-the-art methodologies. As apolipoprotein(a) concentration negatively correlates with isoform size (variable number of Kringle-IV type 2 repeats in human population), subjects were grouped into patients with small, medium and large apolipoprotein(a) isoforms for the statistical analysis. Among the 70 subjects with medium and large apolipoprotein(a) isoforms (>17 Kringle-IV type 2 repeats), subjects with insufficient collaterization (n=57) had a median apolipoprotein(a) concentration of 11.9 nmol/L, while patients with sufficient collaterization (n=13) had a median concentration of 31.3 nmol/L (p=0.033, Mann-Whitney U-test). Among the 52 subjects with medium sized apolipoprotein(a) isoforms (30< Kringle IV type 2 repeats >17) the difference in concentration was even more significant (13.4 vs 33.5 nmol/L, p=0.008).