Electroporation Treatment Research Articles

Anatomically Realistic Simulations of Liver Ablation by Irreversible Electroporation: Impact of Blood Vessels on Ablation Volumes and Undertreatment.

Irreversible electroporation is a novel tissue ablation technique which entails delivering intense electrical pulses to target tissue, hence producing fatal defects in the cell membrane. The present study numerically analyzes the potential impact of liver blood vessels on ablation by irreversible electroporation because of their influence on the electric field distribution. An anatomically realistic computer model of the liver and its vasculature within an abdominal section was employed, and blood vessels down to 0.4 mm in diameter were considered. In this model, the electric field distribution was simulated in a large series of scenarios (N = 576) corresponding to plausible percutaneous irreversible electroporation treatments by needle electrode pairs. These modeled treatments were relatively superficial (maximum penetration depth of the electrode within the liver = 26 mm) and it was ensured that the electrodes did not penetrate the vessels nor were in contact with them. In terms of total ablation volume, the maximum deviation caused by the presence of the vessels was 6%, which could be considered negligible compared to the impact by other sources of uncertainty. Sublethal field magnitudes were noticed around vessels covering volumes of up to 228 mm3. If in this model the blood was substituted by a liquid with a low electrical conductivity (0.1 S/m), the maximum volume covered by sublethal field magnitudes was 3.7 mm3 and almost no sublethal regions were observable. We conclude that undertreatment around blood vessels may occur in current liver ablation procedures by irreversible electroporation. Infusion of isotonic low conductivity liquids into the liver vasculature could prevent this risk.

Possibilities of the method of irreversible electroporation in treatment of the local and widespread pancreatic cancer

Methods of a local destruction of tumors didn’t find till today wide circulation in treatment of patients with formations of the pancreas (P). It is bound to features of blood supply, anatomical and histological structure of PZh, and also a large number of complications and a recurrence.The technique of the irreversible elektroporation (IE) represents a new unique method of not thermal ablyation at which impact on tissues is carried out by short electric impulses of high voltage (to 3 kV) that involves irreversible rising of permeability of cellular membranes and death of cells. The optimum mechanism of rising of permeability of a cellular membrane electric impulses concerning their frequency or repetitions is yet not up to the end clear; it is recognized that outcomes depend on amplitude, duration and number of impulses. Influence has to be synchronized with a cordial rhythm in order to avoid development of an arrhythmia. Existence at the patient of an arrhythmia and the artificial driver of a rhythm is contraindication to carrying out an elektroporation.We have experience of use of a technique for 18 patients with a locally-spread pancreatic cancer. It was succeeded to reflect the main advantages of a new technique in our experience, such as comparative simplicity of workmanship, safety for vascular and pro-current structures, the minimum impact on function of a pancreas.Efficiency of a destruction is proved to ultrasonic, computer and morphological researches in the postoperative period. The maximum term of observation made 19 months.Though exact indications to use of NE still accurately aren’t defined, the international experience and the first own data allow to state efficiency of new technology in palliative surgical treatment of perivascular tumors of a pancreas, and also its safety.

The Safety and Efficacy of Irreversible Electroporation for Large Hepatocellular Carcinoma.

This study aimed to investigate the safety and effectiveness of irreversible electroporation ablation for unresectable large liver cancer. Fourteen patients were enrolled: 8 with large hepatocellular carcinoma (tumor diameter: 5.1-11.5 cm) and 6 with medium hepatocellular carcinoma (tumor diameter: 3.0-4.1 cm). All patients received percutaneous irreversible electroporation ablation. Ablation time and the incidence of complications were assessed by a t test. Post-irreversible electroporation and regular contrast-enhanced computerized tomography scans were performed to investigate the effect of tumor size (large vs medium) on irreversible electroporation treatment efficacy; 4-table data were assessed using a Fisher exact test. The 14 patients completed irreversible electroporation ablation successfully. In the large hepatocellular carcinoma group, no major complications occurred in the perioperative period. Minor complications comprised bloating, hypokalemia, edema, low white blood cells, and blood clotting abnormalities. All complications were mild and improved after symptomatic treatment. The frequency of minor complications was not significantly different (P > .05) compared with the medium hepatocellular carcinoma group. The average follow-up time was 2.8 ± 2.1 months and complete ablation was achieved in 25% (2/8; residual = 75%). For the patients with medium hepatocellular carcinoma, the mean follow-up time was 4.3 ± 3.2 months; the rate of complete ablation was 66.6% (4/6; residual rate = 33.3%). The complete ablation rate was not statistically different between the 2 groups (P > .05). Irreversible electroporation ablation for unresectable large hepatocellular carcinoma is safe, with no major complications. Short-term efficacy is relatively good; however, long-term efficacy remains to be explored.

Modeling of Transmembrane Potential in Realistic Multicellular Structures before Electroporation

Many approaches for studying the transmembrane potential (TMP) induced during the treatment of biological cells with pulsed electric fields have been reported. From the simple analytical models to more complex numerical models requiring significant computational resources, a gamut of methods have been used to recapitulate multicellular environments in silico. Cells have been modeled as simple shapes in two dimensions as well as more complex geometries attempting to replicate realistic cell shapes. In this study, we describe a method for extracting realistic cell morphologies from fluorescence microscopy images to generate the piecewise continuous mesh used to develop a finite element model in two dimensions. The preelectroporation TMP induced in tightly packed cells is analyzed for two sets of pulse parameters inspired by clinical irreversible electroporation treatments. We show that high-frequency bipolar pulse trains are better, and more homogeneously raise the TMP of tightly packed cells to a simulated electroporation threshold than conventional irreversible electroporation pulse trains, at the expense of larger applied potentials. Our results demonstrate the viability of our method and emphasize the importance of considering multicellular effects in the numerical models used for studying the response of biological tissues exposed to electric fields.

Real-time monitoring of cytotoxic effects of electroporation on breast and colon cancer cell lines

PurposeTo study the effects of electroporation on different cell lines. MaterialThe effects of electroporation on human breast cancer (MDA-MB-231), human colon cancer (SW-480 and HCT-116), human fibroblast cell line (MRC-5), primary human aortic smooth muscle cells (hAoSMC) and human umbilical vein endothelial cells (HUVEC) were studied. Real-time technology was used for cell viability monitoring. Acridine orange/ethidium bromide assay was applied for cell death type determination. A numerical model of electroporation has been proposed. ResultsElectroporation induced inhibition of cell viability on dose (voltage) dependent way. The electroporation treatment 375–437.5Vcm−1 caused irreversible electroporation of cancer cells and reversible electroporation of healthy cells. The application of lower voltage rating (250Vcm−1) led to apoptosis as the predominant type of cell death, whereas the use of higher voltage (500Vcm−1) mainly caused necrosis. ConclusionElectroporation represents a promising method in cancer treatment. Different cancer cell lines had different response to the identical electroporation treatment. Electroporation 375–437.5Vcm−1 selectively caused permanent damage of cancer cells (SW-480), while healthy cells (MRC-5, hAoSM and HUVEC) recovered after 72h. The type of cell death is dependent of electroporation conditions. The proposed numerical model is useful for the analysis of phenomena related to electroporation treatment.

Transdermal Delivery of Hyaluronan Tetrasaccharide by Constant Current Iontophoresis

It is well known that scars, wrinkles, and intra articular diseases such as rheumatoid arthritis can be healed by injecting hyaluronan (HA) into the skin and joints. However, based on its varying molecular size, skin penetration of HA may be limited. In this study, we aimed to investigate the effect of transdermal enhancements such as electroporation (EP) and iontophoresis (IP) on the in vitro skin permeability of HA tetrasaccharide (HA4) to deliver HA4 into skin effectively. The effects of EP and IP on the skin permeation of HA4 were studied in in vitro skin permeation experiments. Cumulative amounts of HA4 through full-thickness skin after 6 h were 0.3 μg/cm2 for passive diffusion, 2.3 μg/cm2 after application of EP (100 V, 10 ms, 50 times), 2310.7 μg/cm2 after application of IP (cathodal IP, 0.1 mA/cm2), and 797.9 μg/cm2 after application of IP (cathodal IP, 0.05 mA/cm2), respectively. The skin permeability of the IP (cathodal IP, 0.1 mA/cm2) treatment was about 7700 and 1000-fold increased than that of passive diffusion and the EP treatment. The cumulative amount of HA4 through stripped skin after 6 h was 1384.3 μg/cm2 for passive diffusion. The skin permeability of the cathodal IP (full-thickness skin, 0.05 mA/cm2) treatment was about 1.7-fold increased than that of passive diffusion (stripped skin). We showed that cathodal IP is useful for delivering HA4 into skin effectively.

Cell Electrosensitization Exists Only in Certain Electroporation Buffers.

Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting the first-order model to the experimental results, we determined the uptake due to each train (i.e. the first and the second) and the corresponding resealing constant. Cell sensitization was observed in the growth medium but not in other tested buffers. The effect of pulse repetition frequency, cell size change, cytoskeleton disruption and calcium influx do not adequately explain cell sensitization. Based on our results, we can conclude that cell sensitization is a sum of several processes and is buffer dependent. Further research is needed to determine its generality and to identify underlying mechanisms.

Plant-Based Vaccines: Production and Challenges

Plant-based vaccine technologies involve the integration of the desired genes encoding the antigen protein for specific disease into the genome of plant tissues by various methods. Agrobacterium-mediated gene transfer and transformation via genetically modified plant virus are the common methods that have been used to produce effective vaccines. Nevertheless, with the advancement of science and technology, new approaches have been developed to increase the efficiency of former methods such as biolistic, electroporation, agroinfiltration, sonication, and polyethylene glycol treatment. Even though plant-based vaccines provide many benefits to the vaccine industry, there are still challenges that limit the rate of successful production of these third-generation vaccines. Even with all the limitations, continuous efforts are still ongoing in order to produce efficient vaccine for many human and animals related diseases owing to its great potentials. This paper reviews the existing conventional methods as well as the development efforts by researchers in order to improve the production of plant-based vaccines. Several challenges encountered during and after the production process were also discussed.

Possibilities of irreversable electroporation in treatment of locally advanced pancreatic cancer. Where is the place?

Possibilities of irreversable electroporation in treatment of locally advanced pancreatic cancer. Where is the place?

Irreversable electroporation in treatment of locally advanced pancreatic cancer. Where is the place?

Irreversable electroporation in treatment of locally advanced pancreatic cancer. Where is the place?

Irreversible Electroporation for Treatment of Locally Advanced Pancreatic Cancer

Irreversible Electroporation for Treatment of Locally Advanced Pancreatic Cancer

Effects of Cisplatin Electrochemotherapy on Human Neuroblastoma Cells.

Electrochemotherapy is the usage of electroporation to introduce chemotherapeutic drugs through membrane pores into target cells for cancer treatment. The effectiveness of chemotherapeutic drugs would be increased dramatically when they are used in electrochemotherapy than standard chemotherapy. In the present study, we investigated the effects of cisplatin treatment with electroporation on human SH-SY5Y neuroblastoma cells. SH-SY5Y cells were treated with different concentrations (0.15-24µg/mL) of cisplatin and then exposed to 1500 volts per centimeter (V/cm), 100 microseconds (µs) pulse duration, and 1 Hertz (Hz) electric pulses. Cisplatin alone showed a dose-dependent effect on cell viability. On the other hand, cisplatin+electroporation treatment was more effective than cisplatin treatment alone. Lower doses of cisplatin treatment with electroporation was as effective as higher doses of cisplatin treatment without electroporation. These results indicated that cisplatin cytotoxicity was potentiated after exposure of cells to high intensity electric pulses and low doses of cisplatin can be used with electroporation in the treatment of neuroblastoma.

A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption.

BackgroundElectroporation-based therapies such as electrochemotherapy (ECT) and irreversible electroporation (IRE) are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB) disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This model can be used for individual treatment planning.Material and methodsCell death and BBB disruption models were developed based on the Peleg-Fermi model in combination with numerical models of the electric field. The model calculates the electric field thresholds for cell kill and BBB disruption and describes the dependence on the number of treatment pulses. The model was validated using in vivo experimental data consisting of rats brains MRIs post electroporation treatments.ResultsLinear regression analysis confirmed that the model described the IRE and BBB disruption volumes as a function of treatment pulses number (r2 = 0.79; p < 0.008, r2 = 0.91; p < 0.001). The results presented a strong plateau effect as the pulse number increased. The ratio between complete cell death and no cell death thresholds was relatively narrow (between 0.88-0.91) even for small numbers of pulses and depended weakly on the number of pulses. For BBB disruption, the ratio increased with the number of pulses. BBB disruption radii were on average 67% ± 11% larger than IRE volumes.ConclusionsThe statistical model can be used to describe the dependence of treatment-effects on the number of pulses independent of the experimental setup.

Monitoring Lesion Development during Irreversible Electroporation Treatment using Electrical Impedance Spectroscopy

Irreversible electroporation (IRE) is a new focal ablation therapy that works based on delivering microsecond-long pulsed electric fields (PEFs) to the tissue. Applying the PEFs in the tissue initiates a cascade of different biophysical events at the cellular level that yields cell membrane disruption and eventually cell death. Currently, most IRE procedures are relied on pretreatment planning based on calculating electric field distribution to predict the ablation zone prior to treatment. One clinical limitation of IRE is the absence of methods for real-time treatment evaluation to actively monitor the dimensions of the induced lesion. This information is critical to ensure a complete treatment and minimize collateral damage to the surrounding healthy tissue. In this study we are taking advantage of the biophysical properties of living tissues to address this critical demand. Recent studies has shown that electrical properties of living tissues, as given by the electrical impedance spectrum, are affected during the ablation process. Using microfabrication techniques, we have developed an electrical impedance micro-sensor to collect impedance data along the length of an IRE probe for treatment verification. The probe was first tested on potato tuber, and then used to monitor the lesions in a perfused porcine liver. We used the impedance spectra, along with an electrical model of the tissue, to obtain the conductivity of the tissue before, during, and after completion of treatment. It is shown that electrical impedance spectroscopy could be used as a technique for treatment verification, and when combined with appropriate FEM modeling can determine the lesion dimensions. This technique has the potential to be readily translated for use with other ablation modalities already being used in clinical settings for the treatment of malignancies.

Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments

Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments

Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments.

The retina is a good model for the developing central nervous system. The large size of the eye and most importantly the accessibility for experimental manipulations in ovo/in vivo makes the chicken embryonic retina a versatile and very efficient experimental model. Although the chicken retina is easy to target in ovo by intraocular injections or electroporation, the effective and exact concentration of the reagents within the retina may be difficult to fully control. This may be due to variations of the exact injection site, leakage from the eye or uneven diffusion of the substances. Furthermore, the frequency of malformations and mortality after invasive manipulations such as electroporation is rather high. This protocol describes an ex ovo technique for culturing whole retinal explants from chicken embryos and provides a method for controlled exposure of the retina to reagents. The protocol describes how to dissect, experimentally manipulate, and culture whole retinal explants from chicken embryos. The explants can be cultured for approximately 24 hr and be subjected to different manipulations such as electroporation. The major advantages are that the experiment is not dependent on the survival of the embryo and that the concentration of the introduced reagent can be varied and controlled in order to determine and optimize the effective concentration. Furthermore, the technique is rapid, cheap and together with its high experimental success rate, it ensures reproducible results. It should be emphasized that it serves as an excellent complement to experiments performed in ovo.

Interpulse multifrequency electrical impedance measurements during electroporation of adherent differentiated myotubes

In this study, electrical impedance spectroscopy measurements are performed during electroporation of monolayers of differentiated myotubes. The time resolution of the system (1spectrum/ms) enable 860 full spectra (21 frequencies from 5kHz to 1.3MHz) to be acquired during the time gap between consecutive pulses (interpulse) of a classical electroporation treatment (8 pulses, 100μs, 1Hz). Additionally, the characteristics of the custom microelectrode assembly used allow the experiments to be performed directly in situ in standard 24 multi-well plates. The impedance response dynamics are studied for three different electric field intensities (400, 800 and 1200V/cm). The multifrequency information, analysed with the Cole model, reveals a short-term impedance recovery after each pulse in accordance with the fast resealing of the cell membrane, and a long-term impedance decay over the complete treatment in accordance with an accumulated effect pulse after pulse. The analysis shows differences between the lowest electric field condition and the other two, suggesting that different mechanisms that may be related with the reversibility of the process are activated. As a result of the multifrequency information, the system is able to measure simultaneously the conductivity variations due to ion diffusion during electroporation. Finally, in order to reinforce the physical interpretation of the results, a complementary electrical equivalent model is used.

Percutaneous ablation therapy of hepatocellular carcinoma with irreversible electroporation: MRI findings.

Irreversible electroporation is a new ablation modality. Our purpose was to describe the MRI findings after irreversible electroporation treatment of hepatocellular carcinoma (HCC). In an 18-month period, we treated 24 HCC lesions in 20 patients who were not candidates for surgery. MRI was performed before and 1 month after irreversible electroporation. We used the liver-specific contrast medium gadoxetic acid. We evaluated the size, shape, signal intensity (T1-weighted, T2-weighted, and diffusion-weighted imaging), dynamic contrast enhancement pattern, and signal behavior during the liver-specific phase. Changes in the perilesional parenchyma, perfusion abnormalities, and complications were also recorded. According to the modified Response Evaluation Criteria in Solid Tumors system, 22 of 24 lesions had a complete response, and two lesions showed a partial response and were retreated. The lesions showed a mean size increase of 10%, with a round or oval shape. On the T1-weighted images, we observed a hyperintense core and a hypointense rim. On the T2-weighted sequences, the signal was heterogeneously hypointense. On diffusion-weighted images, 83% of lesions showed restricted diffusion, with b values of 0-800 s/mm(2), whereas in 17% of the lesions, the signal was not clearly discernible for different b values. The apparent diffusion coefficient values did not show statistically significant differences between the baseline (800-1020 × 10(-3) mm(2)/s) and the reassessment after 1 month (900-1100 × 10(-3) mm(2)/s). The necrotic area did not show a signal increase after contrast material injection. Perfusion abnormalities, such as areas of transient hepatic intensity difference, were present in the tissue adjacent to six treated lesions. In two patients, a reduced or absent concentration of the contrast medium was observed during the liver-specific phase around the ablation zone. One patient had an arteriovenous shunt and another had biliary duct dilatation. MRI detects characteristic morphologic and functional changes after irreversible electroporation treatment.

828 Imaging of the ablation zone after focal irreversible electroporation treatment in prostate cancer

828 Imaging of the ablation zone after focal irreversible electroporation treatment in prostate cancer

1:18 PM, Abstract No. 268 - Disparities in the contemporary clinical management of stage Ia renal cell carcinoma: a Surveillance, Epidemiology, and End Results (SEER) study

Purpose: To report safety outcomes of percutaneous irreversible electroporation treatment in 130 patients with prostate adenocarcinomas. Materials and Methods: 130 patients in total with prostate adenocarcinomas in various stages (T1aN0M0-T4NXM1c) underwent IRE treatments (n1⁄4139) from 5/2011 7/2014. 25 patients had history of recurrences after other treatments (5 TURPs, 8 IRE, 4 radiations, 3 HIFUs, 3 prostatectomies alone, 2 prostatectomies þ radiations). MRIs were obtained in all cases before and 10-24 hours after treatments. MRI 3dMapping-Biopsies were used to determine tumor location in 47% of cases. Clinical and/or MRIs follow-ups were obtained at 3, 7, 12, 18, 26, 36 month intervals. Retrospective analysis was performed on 103 patients, who completed at least first 3month-followup. Whole gland ablation (n1⁄423) or partial gland ablation (n1⁄480) were performed. Mean percentage of ablated prostate tissue was 64%. Treatment field also included urethra, neurovascular bundle, bladder, rectum, urethral sphincter, seminal vesicles and small bowel (n 1⁄4 93, 82, 24, 2, 12, 27, 1, respectively). Results: Only 2 of 103 patients (1.9%) needed post-procedural hospitalization (one catheter-induced infection and one rectourethral fistula): no surgical interventions were needed. Average recuperation and Foley catheterization time was 1-2 days. No pain medications above WHO level 1 required. 12 patients (11%) reported a temporary (n1⁄410, o 9 months) and complete (n1⁄42, 43 years) reduction in potency. 3 patients (3%) reported transient dysuria. 14 patients (13%) reported transient urinary retention. 12 patients (11%) developed transient incontinence (n1⁄48) or urgency (n1⁄44) after procedure. 5 patients (4%) reported dysejaculation. 3 patients (3%) reported postprocedural infection (cystitis, epididymo-orchitis, or other infection). Conclusion: IRE offers a new effective therapeutic option for treatment of prostate adenocarcinomas in various stages and improved safety profiles, favorable to other conventional treatments. Further long-term prospective studies are needed for oncological and functional outcomes.