A. HSPG modulate LDL transport across EC monolayers. Endothelial cells were grown to confluence in tissue culture inserts (Falcon, 0.3 μm pore size) in 24 well plates to facilitate its access to the upper (luminal) and lower (subendothelial) surface of endothelial cells. The cells were incubated with medium alone (control) or medium containing 1 unit/ml each of heparinase and heparitinase in the bottom chamber for 2 h at 37°C. 125I-LDL was then added to the cells in the upper chamber and the 125I-LDL appeared in the media from the lower chamber was counted. Values represent Mean ± SD of triplicate measurements. B. Glucosamine treatment decreases LDL transport. Endothelial cells on tissue culture inserts were incubated with medium alone or medium containing 2.5 mM glucosamine for 16 h. 125I-LDL transport was then determined as described above. Figure 3C. Monocyte adhesion to glucosamine treated endothelial cells decreases. Endothelial cells were grown to confluence in 24 well tissue culture plates. Cells were then incubated in medium or medium with glucosamine for 16 h. Subendothelial matrix was prepared from control and glucosamine treated endothelial cells and incubated with (3H)leucine labeled THP-1 monocytes for 2 h. Unbound monocytes were washed four times with DMEM-BSA and the bound radioactivity was determined.