Local delivery of the KCa3.1 blocker, TRAM-34, prevents acute angioplasty-induced coronary smooth muscle phenotypic modulation and limits stenosis

D.L. Tharp, B.R. Wamhoff, H. Wulff, G. Raman, A. Cheong, D.K. Bowles

Research output: Contribution to journalArticlepeer-review


Objective-We previously demonstrated that upregulation of intermediate-conductance Ca2+ -activated K+ channels (KCa 3.1) is necessary for mitogen-induced phenotypic modulation in isolated porcine coronary smooth muscle cells (SMCs). The objective of the present study was to determine the role of KCa3.1 in the regulation of coronary SMC phenotypic modulation in vivo using a swine model of postangioplasty restenosis.
Methods and Results-Balloon angioplasty was performed on coronary arteries of swine using either noncoated or balloons coated with the specific KCa3.1 blocker TRAM-34. Expression of KCa3.1, c-jun, c-fos, repressor element-1 silencing transcription factor (REST), smooth muscle myosin heavy chain (SMMHC), and myocardin was measured using qRT-PCR in isolated medial cells 2 hours and 2 days postangioplasty. KCa3.1, c-jun, and c-fos mRNA levels were increased 2 hours postangioplasty, whereas REST expression decreased. SMMHC expression was unchanged at 2 hours, but decreased 2 days postangioplasty. Use of TRAM-34 coated balloons prevented KCa3.1 upregulation and REST downregulation at 2 hours, SMMHC and myocardin downregulation at 2 days, and attenuated subsequent restenosis 14 and 28 days postangioplasty. Immunohistochemical analysis demonstrated corresponding changes at the protein level.
Conclusion-Blockade of KCa3.1 by delivery of TRAM-34 via balloon catheter prevented smooth muscle phenotypic modulation and limited subsequent restenosis.

Original languageEnglish
Pages (from-to)1084-1089
Number of pages6
JournalArteriosclerosis, Thrombosis, and Vascular biology
Issue number6
Publication statusPublished - 1 Jun 2008

Bibliographical note

This is an un-copyedited author manuscript that was accepted for publication in Arteriosclerosis, Thrombosis, and Vascular Biology,
copyright The American Heart Association. This may not be duplicated or reproduced, other than for personal use or within the “Fair
Use of Copyrighted Materials” (section 107, title 17, U.S. Code) without prior permission of the copyright owner, The American Heart
Association. The final copyedited article, which is the version of record, can be found at Artiosclerosis, Thrombosis, and Vascular
Biology. The American Heart Association disclaims any responsibility or liability for errors or omissions in this version of the manuscript
or in any version derived from it by the National Institutes of Health or other parties.


  • KCa3.1
  • TRAM-34
  • coronary smooth muscle
  • balloon angioplasty
  • phenotypic modulation


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