Summary: Human coronary artery endothelial cell monolayers were incubated with two rhamnan sulfate isoforms (RS1 and RS2) for 24 hrs before the permeability of low density lipoprotein (LDL) was measured. In addition, some monolayers were induced to undergo apoptosis with tumor necrosis factor-α/cycloheximide (TNF-α/CHX ) in the presence or absence of RS1 or RS2 and the permeability of LDL was measured. Both RS1 and RS2 significantly reduced the LDL permeability of control monolayers by 5-fold. Immunostaining of RS1 and RS2-treated monolayers for a major gycocalyx component, heparan sulfate (HS), showed a significant increase in the coverage of HS compared to control monolayers. This suggests that enhanced HS synthesis may mediate the reduction in LDL permeability associated with RS1 and RS2. We believe that the enhanced glycocalyx provides added resistance to the leaky junction pathway that is the main pathway for LDL transport across the endothelium.
Research paper authors: Limary Melissa Cancel,John M Tarbell