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Fesmire CC, Williamson RH, Petrella RA, Kaufman JD, Topasna N, Sano MB. Integrated Time Nanosecond Pulse Irreversible Electroporation (INSPIRE): Assessment of Dose, Temperature, and Voltage on Experimental and Clinical Treatment Outcomes. IEEE Trans Biomed Eng 2024; 71:1511-1520. [PMID: 38145519 PMCID: PMC11035095 DOI: 10.1109/tbme.2023.3340718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
OBJECTIVE This study sought to investigate a novel strategy using temperature-controlled delivery of nanosecond pulsed electric fields as an alternative to the 50-100 microsecond pulses used for irreversible electroporation. METHODS INSPIRE treatments were carried out at two temperatures in 3D tumor models using doses between 0.001 s and 0.1 s. The resulting treatment zones were quantified using viability staining and lethal electric field intensities were determined numerically. Computational modeling was then used to determine parameters necessary for INSPIRE treatments to achieve equivalent treatment zones to clinical electroporation treatments and evaluate the potential for these treatments to induce deleterious thermal damage. RESULTS Lethal thresholds between 1109 and 709 V/cm were found for nominal 0.01 s treatments with pulses between 350 ns and 2000 ns at physiological temperatures. Further increases in dose resulted in significant decreases in lethal thresholds. Given these experimental results, treatment zones comparable to clinical electroporation are possible by increasing the dose and voltage used with nanosecond duration pulses. Temperature-controlled simulations indicate minimal thermal cell death while achieving equivalent treatment volumes to clinical electroporation. CONCLUSION Nanosecond electrical pulses can achieve comparable outcomes to traditional electroporation provided sufficient electrical doses or voltages are applied. The use of temperature-controlled delivery may minimize thermal damage during treatment. SIGNIFICANCE Intense muscle stimulation and the need for cardiac gating have limited irreversible electroporation. Nanosecond pulses can alleviate these challenges, but traditionally have produced significantly smaller treatment zones. This study suggests that larger ablation volumes may be possible with the INSPIRE approach and that future in vivo studies are warranted.
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Vrabel MR, Fesmire CC, Rich MJ, Kobrin RL, Sano MB, Zaharoff DA. A novel in vitro model of clinical cryoablation to investigate the transition zone for focal tumor ablation. Cryobiology 2024; 114:104844. [PMID: 38171448 DOI: 10.1016/j.cryobiol.2023.104844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024]
Abstract
Cryoablation (CA) of solid tumors is highly effective at reducing tumor burden and eliminating small, early stage tumors. However, complete ablation is difficult to achieve and cancer recurrence is a significant barrier to treatment of larger tumors compared to resection. In this study, we explored the relationship between temperature, ice growth, and cell death using a novel in vitro model of clinical CA with the Visual-ICE (Boston Scientific) system, a clinically approved and widely utilized device. We found that increasing the duration of freezing from 1 to 2 min increased ice radius from 3.44 ± 0.13 mm to 5.29 ± 0.16 mm, and decreased the minimum temperature achieved from -22.8 ± 1.3 °C to -45.5 ± 7.9 °C. Furthermore, an additional minute of freezing increased the amount of cell death within a 5 mm radius from 42.5 ± 8.9% to 84.8 ± 1.1%. Freezing at 100% intensity leads to faster temperature drops and a higher level of cell death in the TRAMP-C2 mouse prostate cancer cell line, while lower intensities are useful for slow freezing, but result in less cell death. The width of transition zone between live and dead cells decreased by 0.4 ± 0.2 mm, increasing from one to two cycles of freeze/thaw cycles at 100% intensity. HMGB-1 levels significantly increased with 3 cycles of freeze/thaw compared to the standard 2 cycles. Overall, a longer freezing duration, higher freezing intensity, and more freeze thaw cycles led to higher levels of cancer cell death and smaller transition zones. These results have the potential to inform future preclinical research and to improve therapeutic combinations with CA.
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Affiliation(s)
- Maura R Vrabel
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA.
| | - Christopher C Fesmire
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA.
| | - Matthew J Rich
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA.
| | - Robert L Kobrin
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA.
| | - Michael B Sano
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Department of Molecular and Biomedical Sciences, North Carolina State University, Raleigh, NC, USA.
| | - David A Zaharoff
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA.
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Fesmire CC, Peal B, Ruff J, Moyer E, McParland TJ, Derks K, O’Neil E, Emke C, Johnson B, Ghosh S, Petrella RA, DeWitt MR, Prange T, Fogle C, Sano MB. Investigation of integrated time nanosecond pulse irreversible electroporation against spontaneous equine melanoma. Front Vet Sci 2024; 11:1232650. [PMID: 38352036 PMCID: PMC10861690 DOI: 10.3389/fvets.2024.1232650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024] Open
Abstract
Introduction Integrated time nanosecond pulse irreversible electroporation (INSPIRE) is a novel tumor ablation modality that employs high voltage, alternating polarity waveforms to induce cell death in a well-defined volume while sparing the underlying tissue. This study aimed to demonstrate the in vivo efficacy of INSPIRE against spontaneous melanoma in standing, awake horses. Methods A custom applicator and a pulse generation system were utilized in a pilot study to treat horses presenting with spontaneous melanoma. INSPIRE treatments were administered to 32 tumors across 6 horses and an additional 13 tumors were followed to act as untreated controls. Tumors were tracked over a 43-85 day period following a single INSPIRE treatment. Pulse widths of 500ns and 2000ns with voltages between 1000 V and 2000 V were investigated to determine the effect of these variables on treatment outcomes. Results Treatments administered at the lowest voltage (1000 V) reduced tumor volumes by 11 to 15%. Higher voltage (2000 V) treatments reduced tumor volumes by 84 to 88% and eliminated 33% and 80% of tumors when 500 ns and 2000 ns pulses were administered, respectively. Discussion Promising results were achieved without the use of chemotherapeutics, the use of general anesthesia, or the need for surgical resection in regions which are challenging to keep sterile. This novel therapeutic approach has the potential to expand the role of pulsed electric fields in veterinary patients, especially when general anesthesia is contraindicated, and warrants future studies to demonstrate the efficacy of INSPIRE as a solid tumor treatment.
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Affiliation(s)
- Chris C. Fesmire
- Bioelectricity Lab, UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, NC, United States
| | - Bridgette Peal
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Jennifer Ruff
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Elizabeth Moyer
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Thomas J. McParland
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Kobi Derks
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Erin O’Neil
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Carrie Emke
- Clinical Studies Core, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Brianna Johnson
- Clinical Studies Core, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Shatorupa Ghosh
- Bioelectricity Lab, UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, NC, United States
| | - Ross A. Petrella
- Bioelectricity Lab, UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, NC, United States
| | - Matthew R. DeWitt
- Bioelectricity Lab, UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, NC, United States
| | - Timo Prange
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Callie Fogle
- Department of Clinical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
| | - Michael B. Sano
- Bioelectricity Lab, UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, NC, United States
- Department of Molecular Biomedical Sciences, NC State College of Veterinary Medicine, Raleigh, NC, United States
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Petrella RA, Levit SL, Fesmire CC, Tang C, Sano MB. Polymer Nanoparticles Enhance Irreversible Electroporation In Vitro. IEEE Trans Biomed Eng 2022; 69:2353-2362. [PMID: 35025737 DOI: 10.1109/tbme.2022.3143084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Expanding the volume of an irreversible electroporation treatment typically necessitates an increase in pulse voltage, number, duration, or repetition. This study investigates the addition of polyethylenimine nanoparticles (PEI-NP) to pulsed electric field treatments, determining their combined effect on ablation size and voltages. U118 cells in an in vitro 3D cell culture model were treated with one of three pulse parameters (with and without PEI-NPs) which are representative of irreversible electroporation (IRE), high frequency irreversible electroporation (H-FIRE), or nanosecond pulsed electric fields (nsPEF). The size of the ablations were compared and mapped onto an electric field model to describe the electric field required to induce cell death. Analysis was conducted to determine the role of PEI-NPs in altering media conductivity, the potential for PEI-NP degradation following pulsed electric field treatment, and PEI-NP uptake. Results show there was a statistically significant increase in ablation diameter for IRE and H-FIRE pulses with PEI-NPs. There was no increase in ablation size for nsPEF with PEI-NPs. This all occurs with no change in cell media conductivity, no observable degradation of PEI-NPs, and moderate particle uptake. These results demonstrate the synergy of a combined cationic polymer nanoparticle and pulsed electric field treatment for the ablation of cancer cells. These results set the foundation for polymer nanoparticles engineered specifically for irreversible electroporation.
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Sano MB, DeWitt MR. Thermochromic Tissue Phantoms for Evaluating Temperature Distribution in Simulated Clinical Applications of Pulsed Electric Field Therapies. Bioelectricity 2020; 2:362-371. [PMID: 34476365 PMCID: PMC8370349 DOI: 10.1089/bioe.2020.0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Irreversible electroporation (IRE) induces cell death through nonthermal mechanisms, however, in extreme cases, the treatments can induce deleterious thermal transients. This study utilizes a thermochromic tissue phantom to enable visualization of regions exposed to temperatures above 60°C. Materials and Methods: Poly(vinyl alcohol) hydrogels supplemented with thermochromic ink were characterized and processed to match the electrical properties of liver tissue. Three thousand volt high-frequency IRE protocols were administered with delivery rates of 100 and 200 μs/s. The effect of supplemental internal applicator cooling was then characterized. Results: Baseline treatments resulted thermal areas of 0.73 cm2, which decreased to 0.05 cm2 with electrode cooling. Increased delivery rates (200 μs/s) resulted in thermal areas of 1.5 and 0.6 cm2 without and with cooling, respectively. Conclusions: Thermochromic tissue phantoms enable rapid characterization of thermal effects associated with pulsed electric field treatments. Active cooling of applicators can significantly reduce the quantity of tissue exposed to deleterious temperatures.
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Affiliation(s)
- Michael B. Sano
- UNC/NCSU Joint Department of Biomedical Engineering, Raleigh, North Carolina, USA
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Fesmire CC, Petrella RA, Kaufman JD, Topasna N, Sano MB. Irreversible electroporation is a thermally mediated ablation modality for pulses on the order of one microsecond. Bioelectrochemistry 2020; 135:107544. [DOI: 10.1016/j.bioelechem.2020.107544] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 12/15/2022]
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Electro-Thermal Therapy Algorithms and Active Internal Electrode Cooling Reduce Thermal Injury in High Frequency Pulsed Electric Field Cancer Therapies. Ann Biomed Eng 2020; 49:191-202. [PMID: 32415482 DOI: 10.1007/s10439-020-02524-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
Abstract
Thermal tissue injury is an unintended consequence in current irreversible electroporation treatments due to the induction of Joule heating during the delivery of high voltage pulsed electric fields. In this study active temperature control measures including internal electrode cooling and dynamic energy delivery were investigated as a process for mitigating thermal injury during treatment. Ex vivo liver was used to examine the extent of thermal injury induced by 5000 V treatments with delivery rates up to five times faster than current clinical practice. Active internal cooling of the electrode resulted in a 36% decrease in peak temperature vs. non-cooled control treatments. A temperature based feedback algorithm (electro-thermal therapy) was demonstrated as capable of maintaining steady state tissue temperatures between 30 and 80 °C with and without internal electrode cooling. Thermal injury volumes of 2.6 cm3 were observed for protocols with 60 °C temperature set points and electrode cooling. This volume reduced to 1.5 and 0.1 cm3 for equivalent treatments with 50 °C and 40 °C set points. Finally, it was demonstrated that the addition of internal electrode cooling and active temperature control algorithms reduced ETT treatment times by 84% (from 343 to 54 s) vs. non-cooled temperature control strategies with equivalent thermal injury volumes.
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