Effects of irreversible electroporation on femoral nerves in a rabbit model

A multi-center international study to evaluate the safety, functional and oncological outcomes of irreversible electroporation for the ablation of prostate cancer

BACKGROUND

Irreversible electroporation (IRE) is a novel technique to treat localized prostate cancer with the aim of achieving oncological control while reducing related side effects. We present the outcomes of localized prostate cancer treated with IRE from a multi-center prospective registry.

METHODS

Men with histologically confirmed prostate cancer were recruited to receive IRE. All the patients were proposed for prostate biopsy at 1-year post-IRE ablation. The functional outcomes were measured by the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF-5) questionnaires. The safety of IRE was graded by the treatment-related adverse events (AEs) according to the Common Terminology Criteria for Adverse Events (CTCAE).

RESULTS

411 patients were recruited in this study from July 2015 to April 2020. The median follow-up time was 24 months (IQR 15-36). 116 patients underwent repeat prostate biopsy during 12-18 months after IRE. Clinically significant prostate cancer (Gleason ≥ 3 + 4) was detected in 24.1% (28/116) of the patients; any grade prostate cancers were found in 59.5% (69/116) of the patients. The IPSS score increased significantly from 7.1 to 8.2 (p = 0.015) at 3 months but decreased to 6.1 at 6 months (p = 0.017). Afterwards, the IPSS level remained stable during follow-up. The IIEF-5 score decreased at 3 months from 16.0 to 12.1 (p < 0.001) and then maintained equable afterwards. The rate of AEs was 1.8% at 3 months and then dropped to less than 1% at 6 months and remained stable until 48 months after IRE. Major AEs (Grade 3 or above) were rare.

CONCLUSION

For men with localized prostate cancer, IRE could achieve good urinary and sexual function outcomes and a reasonable oncological result. The real-world data are consistent with earlier studies, including recently published randomized controlled studies. The long-term oncological results need further investigation and follow-up.

Genetically engineered HEK cells as a valuable tool for studying electroporation in excitable cells

Electric pulses used in electroporation-based treatments have been shown to affect the excitability of muscle and neuronal cells. However, understanding the interplay between electroporation and electrophysiological response of excitable cells is complex, since both ion channel gating and electroporation depend on dynamic changes in the transmembrane voltage (TMV). In this study, a genetically engineered human embryonic kidney cells expressing NaV1.5 and Kir2.1, a minimal complementary channels required for excitability (named S-HEK), was characterized as a simple cell model used for studying the effects of electroporation in excitable cells. S-HEK cells and their non-excitable counterparts (NS-HEK) were exposed to 100 µs pulses of increasing electric field strength. Changes in TMV, plasma membrane permeability, and intracellular Ca2+ were monitored with fluorescence microscopy. We found that a very mild electroporation, undetectable with the classical propidium assay but associated with a transient increase in intracellular Ca2+, can already have a profound effect on excitability close to the electrostimulation threshold, as corroborated by multiscale computational modelling. These results are of great relevance for understanding the effects of pulse delivery on cell excitability observed in context of the rapidly developing cardiac pulsed field ablation as well as other electroporation-based treatments in excitable tissues.

Electrochemotherapy of Deep-Seated Tumors: State of Art and Perspectives as Possible "EPR Effect Enhancer" to Improve Cancer Nanomedicine Efficacy

Simple Summary

Electroporation-based therapies (reversible electroporation, irreversible electroporation, electrochemotherapy) are used for the selective treatment of deep-seated tumors. The combination of the structural modifications of the lipid bilayer of cell membranes, due to the application of electrical pulses in the targeted tissue, with the concomitant systemic (intravenous) administration of drugs can be considered as a sort of bridge between local-regional and systemic treatments. A possible further application of these techniques can be envisaged in their use as enhancers of the so-called “enhanced permeability and retention” effect. The intratumoral uptake of drug-loaded nanocarriers concomitant with the application of electric pulses in the target tumor is a new scenario worthy of attention and can represent a potential new frontier for drug delivery in oncology.

Abstract

Surgical resection is the gold standard for the treatment of many kinds of tumor, but its success depends on the early diagnosis and the absence of metastases. However, many deep-seated tumors (liver, pancreas, for example) are often unresectable at the time of diagnosis. Chemotherapies and radiotherapies are a second line for cancer treatment. The “enhanced permeability and retention” (EPR) effect is believed to play a fundamental role in the passive uptake of drug-loaded nanocarriers, for example polymeric nanoparticles, in deep-seated tumors. However, criticisms of the EPR effect were recently raised, particularly in advanced human cancers: obstructed blood vessels and suppressed blood flow determine a heterogeneity of the EPR effect, with negative consequences on nanocarrier accumulation, retention, and intratumoral distribution. Therefore, to improve the nanomedicine uptake, there is a strong need for “EPR enhancers”. Electrochemotherapy represents an important tool for the treatment of deep-seated tumors, usually combined with the systemic (intravenous) administration of anticancer drugs, such as bleomycin or cisplatin. A possible new strategy, worthy of investigation, could be the use of this technique as an “EPR enhancer” of a target tumor, combined with the intratumoral administration of drug-loaded nanoparticles. This is a general overview of the rational basis for which EP could be envisaged as an “EPR enhancer” in nanomedicine.