ABSTRACT
A comparison of phosphodiesterase (PDE) isozyme distribution in cultured human aortic endothelial cells, human microvascular endothelial cells (HMVEC), and HUVEC has been recently reported by Netherton and Maurice. Migration of endothelial cells, which is one of the steps in angiogenesis, is inhibited by elevation of protein kinase activity. Most endothelial cells are characterized by the coexistence of PDE2 and PDE4 along with some PDE3, PDE5, and to a lesser extent to PDE1 and PDE7 depending on blood vessel type, phenotypic state, and culture conditions. Endothelial cells are implicated in various pathologies such as arteriosclerosis, rheumatoid arthritis, diabetic retinopathy, AIDS-associated Kaposi’s sarcoma, and solid tumor growth in which angiogenesis is critical. Vascular endothelium growth factor secreted by smooth muscle cells or tumors represents the major signal inducing proliferation and migration of endothelial cells, thus initiating angiogenesis. Nitric oxide (NO) is known to increase cyclic guanosine monophosphate in endothelial cells, and therefore cGMP is measured as an index of NO production.
