Title: Targeting the Kv1.3 potassium channel for immunosuppression in vascularized composite allotransplantation - a pilot study.

Authors: Theresa Hautz, Christoph Krapf, Johanna Grahammer, Bettina Zelger, Tilman Hickethier, Christoph Seger, Nadine Eberhart, Christoph Wallner, Franka Messner, Katja Kotsch, Andrea Griesmacher, Gerald Brandacher, W P Andrew Lee, Raimund Margreiter, Johann Pratschke, Hartmut Glossmann, Stefan Schneeberger

Journal, date & volume: Transpl. Int., 2013 May , 26, 552-61

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23489391

Abstract
Kv1.3-channels are critically involved in activation and function of effector memory T cells. Blocking Kv1.3-channels was investigated for its effect on skin rejection in a rat limb-transplantation-model. Animals received the Kv1.3-blocker correolide C systemically or locally as intra-graft-treatment in combination with tacrolimus. Systemic (intraperitoneal) administration of correolide C resulted in slight, but significant prolongation of allograft survival compared with untreated and placebo treated controls. In 4/6 correolide C treated animals, histology showed an intact epidermis and a mild infiltrate by day 10. High correolide C plasma trough levels correlated with prolonged allograft survival. A decrease in CD4+ and CD8+ effector memory T cells was observed in allograft skin, peripheral blood and the spleen on day 5. When applied subcutaneously in combination with systemic tacrolimus (30 days+/-anti-lymphocyte serum) detectable, but insignificant prolongation of graft survival was achieved. 2/5 animals showed an intact epidermis and a mild infiltrate until day 45. Tapering systemic tacrolimus and weaning on day 50 resulted in rejection by day 55, regardless of local correolide C treatment. Subcutaneous injection did not lead to systemic plasma levels. The Kv1.3-channel is a potential drug target worth exploring in more detail for immunosuppression in vascularized composite allotransplantation.