Proceedings of The Physiological Society

University of Oxford (2011) Proc Physiol Soc 23, PC345

Poster Communications

Role of Kv1.3 channel in vascular smooth muscle cells proliferation in a porcine model of coronary restenosis

P. Cidad1, L. Novensa2, L. Jiménez-Pérez1, E. Alonso1, M. Roqué2, M. Heras2, J. López-López1, M. Pérez-García1

1. Bioqu

Vascular smooth muscle cells (VSMCs) regulate vessel diameter and determine tissue perfusion, however mature VSMCs are not definitely differentiated and have the ability to switch from a contractile phenotype to a proliferative phenotype. The phenotypic switch implies a profound change in gene expression profile which includes ion channels expression. Due to the large molecular diversity of ion channels, changes in their expression during phenotypic modulation are poorly defined. In a previous work (1) we performed a high-throughput real time PCR screening of ion channels genes as to obtain a global picture of ion channel expression in proliferation. Changes in mRNA and functional expression showed that Kv1.3 channel had a significant role in the phenotypic switch. In this work we try to reproduce these results in a more clinically relevant VSMC proliferation model: porcine coronary proliferation. This model closely resembles the human model and could be suitable for assaying in vivo strategies to inhibit local VSMCs responses after surgical procedures. Animal protocols were all approved by our institutional Care and Use Committee, and are in accordance with the European Community guiding principles. Animals were sedated with intramuscular injection (2 mg/Kg) of azaperon and anesthetized with 30 mg/Kg of intravenous sodium thiopental. Coronary intimal lession was induced by using a guiding catheter from the right femoral artery to the circumflex and the anterior descending coronary arteries, right coronary arteries were used as control. Four weeks after the surgery the animals underwent euthanasia and arteries samples were collected. mRNA expression levels studied by real time PCR showed that accordingly with previous data, Kv1.3 expression increased in injured arteries, when compare to control arteries. By electrophysiological techniques we explored the functional contribution of Kv1.3 in freshly dispersed VSMCs obtained from injured and control arteries. Our data showed that Kv1.3 currents became predominant K+ currents in proliferative VSMCs. Moreover proliferation assays showed that Kv1.3 current is an essential component to the proliferative phenoptype as VSMCs proliferation was inhibited in presence of Kv1.3 blockers (10 nM Margatoxin and 10 nM PAP-1), but not in the presence of another Kv channels. These data suggest that Kv1.3 could be a good therapeutical target to treat restenosis in a good translational animal model, as it is porcine coronary arteries, for testing medical devices such as coated stents with Kv1.3 blockers.

Where applicable, experiments conform with Society ethical requirements