Abstract:

Objective To investigate the in vitro effects of sera of patients with uremia on vascular endothelial cells, and explore their clinical significance. Methods Human umbilical vascular endothelial cells (HUVEC) were treated with sera of patients with uremia (uremic serum group, n=10) and healthy controls (normal serum group, n=10)(volume fraction of 25% for both group) for 24 h, and blank control group was established. The cell morphology was observed by immunohistochemical staining, cell apoptotic rates were determined by flow cytometry, and Real-Time PCR was employed to detect the expression of interleukin-8 (IL-8), endothelin-1 (ET-1) and endothelial nitric oxide synthase (eNOS) mRNA in cells. The culture supernatant fluid was collected, the mass concentrations of IL-8 and ET-1 were measured by ELISA, and the concentration of nitric oxide (NO) was determined by nitrate reduction method. HUVEC were treated with sera of patients with uremia of different volume fractions (10%, 15%, 20% and 25%), and cell proliferation rates were determined by MTS method. Results The number of HUVEC in uremic serum group was smaller than those of blank control group and normal serum group, and condensed or fragmented nuclei and condensed cytoplasm were observed in uremic serum group. The cell apoptotic rate in uremic serum group [(55.59±5.21)%] was significantly higher than those in normal serum group [（12.20±6.20）%] and blank control group [（0.38±0.31）%] （P<0.05）. Compared with normal serum group, the expression of IL-8 and ET-1 mRNA in HUVEC increased, the expression of eNOS mRNA in HUVEC decreased, the mass concentrations of IL-8 and ET-1 in cell supernatant fluid increased, and the concentration of NO decreased in uremic serum group. The cell proliferation rates of HUVEC treated with uremic sera of different volume fractions were significantly lower than corresponding ones in normal serum group and blank control group （P<0.05）. Conclusion Treatment with sera of patients with uremia may change the morphology, inhibit the proliferation, promote the apoptosis, enhance the secretion of IL-8 and ET-1 and inhibit the secretion of eNOS and NO of HUVEC, and lead to the dysfunction of vascular endothelial cells. Patients with uremia are under chronic inflammatory state in a long term, and may have a greater risk of developing cardiovascular diseases.

Key words: uremia, vascular endothelial cell, interleukin-8, endothelin-1, endothelial nitric oxide synthetase