Expression of AQP1 in cultured human endothelial cells is upregulated by high glucose

Objective Aquaporin-1 (AQP1) has been claimed to be the molecular counterpart of ultrasmall pore during peritoneal dialysis ( PD) . This study was done to investigate the effect of glucose on AQP1 expression in human endothelial cells. Methods Human umbilical vein endothelial cells (HUVECs) were cultured in serum-containing media until they reached subconfluence. Then the cells were exposed to the media supplemented with glucose in different concentrations or 4. 25% mannitol for 6, 24, 48,72 h. Total RNA and protein were extracted. Semi-quantative RT-PCR and Western blotting were used to detect the expression of AQP1. Results There was weak detectable AQP1 in cultured HUVECs at both mRNA and protein levels. When exposing HUVECs to high glucose for 6 h, there was no significant difference of AQP1 expression with comparison to those grown in media without glucose supplementation. But after incubation for 24 h, the expression of AQP1 was increased with increasing glucose concentration. Cells grown in media containing 4. 25% glucose showed 1.5 to 2 folds higher AQP1 expression than those grown in media without glucose supplementation (P 0. 05). Futher increases were observed when the exposure time was prolonged to 48 h and 72 h. No difference of AQP1 expression existed between the cells grown in media containing 4. 25% glucose and 4. 25% mannitol. Conclusion The present study suggests that expression of AQP1 mRNA and protein in human endothelial cells can be upregulated by glucose. Its upregulation is mainly through hyperos-molarity.