Non Thermal Irreversible Electroporation: Novel Technology for Vascular Smooth Muscle Cells Ablation

Elad Maor,Boris Rubinsky,Antoni Ivorra,Pieter H Reitsma

doi:10.1371/journal.pone.0004757

Elad Maor, Boris Rubinsky + Show 2 more

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https://doi.org/10.1371/journal.pone.0004757

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Abstract

BackgroundNon thermal Irreversible electroporation (NTIRE) is a new tissue ablation method that induces selective damage only to the cell membrane while sparing all other tissue components. Our group has recently showed that NTIRE attenuated neointimal formation in rodent model. The goal of this study was to determine optimal values of NTIRE for vascular smooth muscle cell (VSMC) ablation.Methods and Results33 Sprague-Dawley rats were used to compare NTIRE protocols. Each animal had NTIRE applied to its left common carotid artery using a custom-made electrodes. The right carotid artery was used as control. Electric pulses of 100 microseconds were used. Eight IRE protocols were compared: 1–4) 10 pulses at a frequency of 10 Hz with electric fields of 3500, 1750, 875 and 437.5 V/cm and 5–8) 45 and 90 pulses at a frequency of 1 Hz with electric fields of 1750 and 875 V/cm. Animals were euthanized after one week. Histological analysis included VSMC counting and morphometry of 152 sections. Selective slides were stained with elastic Van Gieson and Masson trichrome to evaluate extra-cellular structures. The most efficient protocols were 10 pulses of 3500 V/cm at a frequency of 10 Hz and 90 pulses of 1750 V/cm at a frequency of 1 Hz, with ablation efficiency of 89±16% and 94±9% respectively. Extra-cellular structures were not damaged and the endothelial layer recovered completely.ConclusionsNTIRE is a promising, efficient and simple novel technology for VMSC ablation. It enables ablation within seconds without causing damage to extra-cellular structures, thus preserving the arterial scaffold and enabling endothelial regeneration. This study provides scientific information for future anti-restenosis experiments utilizing NTIRE.

Highlights

Vascular smooth muscle cells (VSMC) are the cellular component of the medial layer of adult arteries and play a prominent role in arterial physiology and pathology. [1,2] Together with arterial remodeling, vascular smooth muscle cell (VSMC) proliferation plays a major role in luminal loss following angioplasty.[2,3] VSMC proliferation is even more important in the clinical scenario of instent restenosis, where remodeling is prevented by the firm scaffolding of the stent.[4]To date, different methods to stop the proliferation of VSMC have been suggested
This study provides scientific information for future anti-restenosis experiments utilizing Non thermal Irreversible electroporation (NTIRE)
NTIRE ablation results were achieved in Groups 1 and 7 (Figure 1)

Summary

Introduction

Different methods to stop the proliferation of VSMC have been suggested These methods include cryoplasty, brachytherapy, photodynamic therapy, drug-eluting stents and genetic manipulations using gene-therapy. Irreversible Electroporation (IRE) is a phenomenon in which high electrical fields are delivered across cells in short, micro to millisecond pulses These pulses create irreversible defects (pores) in the cell membrane lipid bilayer, causing cell death through loss of cell homeostasis.[7] Irreversible electroporation is associated with high electrical fields and is often reported in conjunction with tissue thermal damage caused by electrical Joule heating.[8,9,10] Joule heating is the dissipation of energy when an electrical current flows through a medium with resistance to current. The goal of this study was to determine optimal values of NTIRE for vascular smooth muscle cell (VSMC) ablation

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