Adrenomedullin and the endothelial cell functions in vitro

Objective To explore the effects of adrenomedullin(AM) on human umbilical vein endothelial cells (HUVECs) and possible mechanisms involved. Methods The HUVECs were selected to be a model and the following aspects were studied: (1) Effects of high glucose (30 mmol/L) on the endothelial dysfunction induced. (2) The role of protein kinase C (PKC)α and PKCδ in the endothelial dysfunction induced by high glucose and the effects of AM. The translocation of PKCδ or PKCα in a single HUVEC was observed by laser-scanning confocal microscope and the expressions analysis was conducted quantificationally by Western blotting. HUVECs were cultured and divided into 3 groups: (1) Matched control group; (2) High glucose group (30 mmol/L glucose); (3) AM (10~(-9), 10~(-8), 10~(-7) mol/L) + highglucosegroupHUVECswereincubated with AM for 48 h. Results (1) High glucose could induce HUVECs dysfunction: increased apoptosis, decreased NO concentration and increased sICAM level of HUVECs. AM reversed the above changes of HUVECs induced by high glucose. (2) It was observed that AM inhibited the translocation of PKCα from plasma to nucleus in HUVECs induced by high glucose and the translocation of PKCδ from nucleus to plasma and membrane in HUVECs. (3) AM inhibited the increasing expressions of PKCδ in HUVECs induced by high glucose. The expressions of PKCα in high glucose group were not different from that of the control. Conclusion AM appears to correct the endothelial cell dysfunctions induced by high glucose. The inhibition of PKCα and PKCδ seems to play some roles during the process.