title: Optimization of Irreversible Electroporation Protocols for In-vivo Myocardial Decellularization.
abstract: BACKGROUND
  Irreversible electroporation (IRE) is a non-thermal cell ablation approach that induces selective damage to cell membranes only. The purpose of the current study was to evaluate and optimize its use for in-vivo myocardial decellularization.
  
  
  METHODS
  Forty-two Sprague-Dawley rats were used to compare myocardial damage of seven different IRE protocols with anterior myocardial infarction damage. An in-vivo open thoracotomy model was used, with two-needle electrodes in the anterior ventricular wall. IRE protocols included different combinations of pulse lengths (70 vs. 100 μseconds), frequency (1, 2, 4 Hz), and number (10 vs. 20 pulses), as well as voltage intensity (50, 250 and 500 Volts). All animals underwent baseline echocardiographic evaluation. Degree of myocardial ablation was determined using repeated echocardiography measurements (days 7 and 28) as well as histologic and morphometric analysis at 28 days.
  
  
  RESULTS
  All animals survived 28 days of follow-up. Compared with 50V and 250V, electroporation with 500V was associated with significantly increased myocardial scar and reduction in ejection fraction (67.4%±4% at baseline vs. 34.6%±20% at 28 days; p <0.01). Also, compared with pulse duration of 70 μsec, pulses of 100 μsec were associated with markedly reduced left ventricular function and markedly increased relative scar area ratio (28%±9% vs. 16%±3%, p = 0.02). Decreasing electroporation pulse frequency (1Hz vs. 2Hz, 2Hz vs. 4Hz) was associated with a significant increase in myocardial damage. Electroporation protocols with a greater number of pulses (20 vs. 10) correlated with more profound tissue damage (p<0.05). When compared with myocardial infarction damage, electroporation demonstrated a considerable likeness regarding the extent of the inflammatory process, but with relatively higher levels of extra-cellular preservation.
  
  
  CONCLUSIONS
  IRE has a graded effect on the myocardium. The extent of ablation can be controlled by changing pulse length, frequency and number, as well as by changing electric field intensity.
authors.affiliation: Tamman Cardiovascular Research Institute, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Zager
authors.affiliation: Tamman Cardiovascular Research Institute, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.|Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Kain
authors.affiliation: Tamman Cardiovascular Research Institute, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.|Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Natalie
authors.initials: N
authors.lastname: Landa
authors.affiliation: Tamman Cardiovascular Research Institute, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.|Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Leor
authors.affiliation: Tamman Cardiovascular Research Institute, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.|Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Tel-Hashomer, Ramat-Gan, Israel.
authors.forename: Elad
authors.initials: E
authors.lastname: Maor
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D004562:Electrocardiography; D004566:Electrodes; D018274:Electroporation / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006321:Heart / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000503:physiopathology; D009206:Myocardium / Q000166:cytology*; D017207:Rats, Sprague-Dawley