[Study on up-regulation of the expression of angiotensin-converting enzyme-2 in human umbilical vein endothelial cells by telmisartan].

Objective: To investigate the effect of telmisartan on the protein and gene expression of angiotensin-converting enzyme-2 (ACE2) in human umbilical vein endothelial cells (HUVECs).
Methods: HUVECs were treated with various concentrations of telmisartan (10(-7), 10(-6) and 10(-5) mol/L) for 24 hours. In a time-control experiment, HUVECs were treated with telmisartan at the final concentration of 10(-6) mol/L for 6, 12 and 24 hours, respectively. In another experiment, HUVECs were treated with PD123319 (10(-6) mol/L) only or combined with same final concentration of telmisartan for 12 hours, respectively. Changes in both protein and gene expression of ACE2 were determined with Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) technique, respectively.
Results: Telmisartan induced a concentration and time dependent increase in both protein and gene expression of ACE2 (P<0.05 or P<0.01). Compared with control group, treatment of HUVECs with telmisartan at the concentration of 10(-7), 10(-6) and 10(-5) mol/L stimulated 1.5-, 2.7- and 4.6-fold increase in the ACE2 protein expression, as well as 1.2-, 2.3- and 4.5-fold increase in its gene expression, respectively. After treatment of HUVECs with telmisartan for 6, 12, and 24 hours at the concentration of 10(-6) mol/L, the ACE2 protein expression increased 1.6-, 2.7- and 4.2-fold, and its gene expression increased 1.3-, 2.3- and 4.0-fold, respectively. Compared with control and telmisartan groups, PD123319 had no effect on both protein and gene expression of ACE2 (P>0.05).
Conclusion: Telmisartan up-regulates the protein and gene expression of ACE2 in HUVECs in a concentration and time dependent manner. This effect may be mediated via its specific pathway.