Objective      To investigate the damage effect of protein-bound uremic toxins on human umbilical vein endothelial cells (HUVECs).       Methods      HUVECs were cultured in growth medium with the addition of different concentrations (0.4%

1%

2% and 4%) of proteins collected from the uremic patients or the normal persons for different time (24

48 and 72 h)

and the blank control group was established. The cell morphology was observed with an inverted phase contrast microscope. The cell proliferation rate

nitric oxide (NO) concentration and nitric oxide synthase (NOS) activity were detected by respective assay kits. The cell apoptotic rate and the level of endothelial microparticles (EMPs) were detected by flow cytometry (FCM).       Results      Compared with the normal group and the blank control group

the uremic group showed irregular cell morphology

lower cell proliferation rate (P0.05)

less NO in culture supernatant (P0.05)

and lower NOS activity(P0.05). The level [(62.57±1.59)%] of the EMPs in the uremic group was significantly higher than that [(7.3±0.57)%] in the blank control group and that [(13±0.94)%] in the normal group (P0.05). However

the uremic protein solution had no effect on cell apoptosis.       Conclusion      The serum protein solution from the uremic patients may change the HUVEC morphology

inhibit the HUVEC proliferation and NO secretion

decrease the NOS activity

and promote the released EMPs from the HUVECs

which may lead to the dysfunction of the vascular endothelial cells.