Ammarguellat F, Gogusev J, Drueke TB
Direct effect of erythropoietin on rat vascular smooth muscle cells
via a putative erythropoietin receptor
Nephrol Dial Transplant
(Apr) 11:687-692 1996

It is fairly well established that at least some uraemic patients
manifest a BP rise after starting rHuEPO treatment. Several factors
may contribute to raise systemic vascular resistance during rHuEPO
therapy including a direct vasoconstrictor effect, loss of hypoxic
vasodilatation, increased blood viscosity, increased intracellular
Ca++ content, activation of the renin-angiotensin and the sympathetic
systems and the release of endothelin (see review by Nowicki, J
Human Hypertension 9:81,1995).
Receptors for erythropoietin have already been demonstrated on
endothelial cells where this autocoid exerts mitogenic and
chemotactic effects. At present, however, the link between
erythropoietin and hypertension has remained poorly defined.
Ammarguellat and co-workers have now further explored the
possibility of a direct effect of rhEPO on the vascular smooth muscle
cells (VSMC). In this preliminary study they have demonstrated that
rHuEPO promotes the mRNA expression of the EPO receptor in VSMC of
both SH and WKY rats. However, VSMC growth rate was enhanced (to a
moderate degree) only in the SHR while binding studies failed to show
specific binding of radiolabelled rHuEpo by VSCM in both strains.
Comment: This study is of great potential interest
but many grey areas remain in this interesting issue. (Carmine
Zoccali, M.D., Reggio Calabria, Italy)