Study of the Binding Capacity of Heparin Functionalized Magnetic Microparticles for Cardiac Lipoprotein Lipase and their Preliminary Evaluation Ex Vivo in Rat Hearts.

Magnetic particles were modified with covalently-bound surface heparin (HEPMag). The amount and activity of bound heparin was investigated with the toluidine blue, APTT, Kinetichrome Anti-IIa and western blot assays. The particles bound 40 μg/mg (0.42 U/mg) and exhibited excellent anticoagulant activity. However, the activity was 5x less than that of free heparin. The HEPMag particles were then utilized to measure their lipoprotein lipase (LPL) binding potential and compared to commercially available heparin-bound particles (SiMAG-Heparin). HEPMag particles bound 98% LPL compared to 79% for SiMAG-Heparin particles. In addition, the HEPMag particles retained the LPL much better: Upon incubation with 5 U/mL free heparin, HEPMag particles released only 7% of the bound LPL compared to 67% for the SiMAG-Heparin particles. Being able to capture LPL in the heart might be useful for the investigation of the fat acid metabolism in diabetes. Ex vivo retrograde heart perfusion studies in rats with the HEPMag particles showed that LPL could be removed from the coronary lumen. These heparin surface modified parties are thus potential tools to magnetically target the coronary arteries and remove LPL in a selective way. [ABSTRACT FROM AUTHOR]