gms | German Medical Science

28. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

24. bis 27.11.2004, Hannover

Erythropoietin increases asymmetric dimethylarginine (ADMA) in endothelial cells - Role of Dimethylarginine Dimethylaminohydrolase

Erythropoietin erhöht asymmetrisches Dimethylarginin (ADMA) in Endothelzellen: die Rolle von Dimethylarginin-Dimethylaminohydrolase

Meeting Abstract (Hypertonie 2004)

  • F. Scalera - Institut für klinische Pharmakologie
  • J. Kielstein - Institut für klinische Pharmakologie
  • J. Martens-Lobenhoffer - Zentrum Innere Mediizin, Abt. Nephrologie, Magdeburg
  • S. Postel - Zentrum Innere Mediizin, Abt. Nephrologie
  • M. Täger - Institut für Medizintechnologie Hannover
  • S. Bode-Böger - Institut für Medizintechnologie Hannover

Hypertonie 2004. 28. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Hannover, 24.-27.11.2004. Düsseldorf, Köln: German Medical Science; 2005. Doc04hochP8

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Veröffentlicht: 10. August 2005

© 2005 Scalera et al.
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Background: Recombinant human erythropoietin (rHuEPO) therapy frequently causes hypertension in humans and animals with chronic renal failure. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS) and its accumulation has been associated with reducing NO bioavailability and increasing superoxide generation. We investigated whether epoetin beta (EPO) or darbepoetin alfa (NESP) can modify the levels of ADMA in endothelial cells.

Methods: Human umbilical vein endothelial cells (HUVECs) from the third passage were incubated for 24 h in presence of different concentrations of EPO or NESP (0, 100 and 200 U/ml, respectively). The levels of ADMA, allantoin, nitrate and nitrite in conditioned media, and the activity of dimethylarginine dimethylaminohydrolase (DDAH), the content of thiols and reactive oxygen species (ROS) in endothelial cells were determined.

Results: When endothelial cells were exposed to EPO or NESP, ADMA concentration in the cell culture medium increased significantly versus control (26% vs. control). This effect was associated with a reduced activity of DDAH by 24%, the enzyme that degrades ADMA. Furthermore, EPO-induced accumulation of ADMA was associated with reduced nitric oxide synthesis (20% vs control) and an increase in oxidative stress. Both allantoin, a marker of oxygen free radical generation, and ROS increased significantly after EPO or NESP treatment compared to control (28% and 20% vs. control, respectively). The antioxidant pyrrollidine dithiocarbamate (PDTC) preserved DDAH activity and reduced ADMA accumulation in the same way as the coincubation with the anti-EPO neutralizing antibody.

Conclusions: EPO and NESP post-translationally impair DDAH activity via increased oxidative stress, causing ADMA as an important cardiovascular risk factor to accumulate and inhibit NO synthesis. Due to this preliminary data the therapeutic role of rHuEPO in cardiovascular settings has to be carefully monitored.