In this application for an exploratory/development grant (R21), the PI proposes to study the role of applied electrical potentials on angiogenesis, the growth, migration, and formation of new capillaries by endothelial cells (ECs). The PI reports the new observation that exposure of capillary ECs to low-level applied electrical potentials significantly increased EC growth over several days, suggesting that this treatment might be useful to improve wound healing. Although electric field effects have been previously reported in wound healing studies, the mechanism(s) of these effects, particularly with respect to angiogenesis, are unknown. The PI has found that direct current (DC) negative potentials stimulated while positive potentials inhibited EC growth or caused necrosis. In vitro and in vivo angiogenesis models are proposed.
The Specific Aims are to: 1) determine the optimal potential conditions for EC stimulation;
This aim will use DC, pulse wave DC, and AC current approaches. 2) determine the mechanism of EC growth stimulation;
This aim will examine whther an electrochemical process at the electrode generate a chemical species (which could be detected in the media) which affects EC growth. These experiments will use cyclic voltammetry to evaluate the media for the presence of these putative species. The second part of these experiments will examine whether negative potential stimulates EC production, release, or activation of FGF or VEG-F. These experiments will use various molecular techniques to determine wether these growth factors are mobilized into the media by negative potential from EC cytoplasm, cell surfaces, or extracellular matrix. These latter experiments will be performed using cell-free extracellular matrix derived from electric potential-treated cultures, and subsequently exposed to normal ECs. 3) to determine the influence of negative potential in vitro (using a scrape wound healing assay, SWA) and in vivo (using a chorioallantoic membrane (CAM) assay). The SWA will be performed directly on optically transparent ITO glass substrate, and numbers of ECs entering the denuded areas monitored. CAMs will be sham- treated or treated with negative potential, and then density and number of vessels quantified. These experiments may lead to new adjunct therapies to promote angiogenesis in a variety of clinical situations.
