Reduction of muscle contraction and pain in electroporation-based treatments: An overview

BACKGROUND

In the first studies of electrochemotherapy (ECT), small cutaneous metastases were treated and only mild or moderate pain was observed; therefore, pain was not considered a significant issue. As the procedure began to be applied to larger cutaneous metastases, pain was reported more frequently. For that reason, reduction of both muscle contractions and pain have been investigated over the years.

AIM

To present an overview of different protocols described in literature that aim to reduce muscle contractions and pain caused by the electroporation (EP) effect in both ECT and irreversible EP treatments.

METHODS

Thirty-three studies published between January 1999 and November 2020 were included. Different protocol designs and electrode geometries that reduce patient pain and the number of muscle contractions and their intensity were analysed.

RESULTS

The analysis showed that both high frequency and bipolar/biphasic pulses can be used to reduce pain and muscle contractions in patients who undergo EP treatments. Moreover, adequate electrode design can decrease EP-related morbidity. Particularly, needle length, diameter and configuration of the distance between the needles can be optimised so that the muscle volume crossed by the current is reduced as much as possible. Bipolar/biphasic pulses with an inadequate pulse length seem to have a less evident effect on the membrane permeability compared with the standard pulse protocol. For that reason, the number of pulses and the voltage amplitude, as well as the pulse duration and frequency, must be chosen so that the dose of delivered energy guarantees EP efficacy.

CONCLUSION

Pain reduction in EP-based treatments can be achieved by appropriately defining the protocol parameters and electrode design. Most results can be achieved with high frequency and/or bipolar/biphasic pulses. However, the efficacy of these alternative protocols remains a crucial point to be assessed further.

A Systematic Review about Imaging and Histopathological Findings for Detecting and Evaluating Electroporation Based Treatments Response

BACKGROUND

Imaging methods and the most appropriate criteria to be used for detecting and evaluating response to oncological treatments depend on the pathology and anatomical site to be treated and on the treatment to be performed. This document provides a general overview of the main imaging and histopathological findings of electroporation-based treatments (Electrochemotherapy-ECT and Irreversible electroporation-IRE) compared to thermal approach, such as radiofrequency ablation (RFA), in deep-seated cancers with a particular attention to pancreatic and liver cancer.

METHODS

Numerous electronic datasets were examined: PubMed, Scopus, Web of Science and Google Scholar. The research covered the years from January 1990 to April 2021. All titles and abstracts were analyzed. The inclusion criteria were the following: studies that report imaging or histopathological findings after ablative thermal and not thermal loco-regional treatments (ECT, IRE, RFA) in deep-seated cancers including pancreatic and liver cancer and articles published in the English language. Exclusion criteria were unavailability of full text and congress abstracts or posters and different topic respect to inclusion criteria.

RESULTS

558 potentially relevant references through electronic searches were identified. A total of 38 articles met the inclusion criteria: 20 studies report imaging findings after RFA or ECT or IRE in pancreatic and liver cancer; 17 studies report histopathological findings after RFA or ECT or IRE; 1 study reports both imaging and histopathological findings after RFA or ECT or IRE.

CONCLUSIONS

Imaging features are related to the type of therapy administrated, to the timing of re-assessment post therapy and to the imaging technique being used to observe the effects. Histological findings after both ECT and IRE show that the treated area becomes necrotic and encapsulated in fibrous tissue, suggesting that the size of the treated lesion cannot be measured as an endpoint to detect response. Moreover, histology frequently reported signs of apoptosis and reduced vital tissue, implying that imaging criteria, which take into account the viability and not the size of the lesion, are more appropriate to evaluate response to treatment.

Radiomic and Artificial Intelligence Analysis with Textural Metrics Extracted by Contrast-Enhanced Mammography and Dynamic Contrast Magnetic Resonance Imaging to Detect Breast Malignant Lesions

Purpose:The purpose of this study was to discriminate between benign and malignant breast lesions through several classifiers using, as predictors, radiomic metrics extracted from CEM and DCE-MRI images. In order to optimize the analysis, balancing and feature selection procedures were performed. Methods: Fifty-four patients with 79 histo-pathologically proven breast lesions (48 malignant lesions and 31 benign lesions) underwent both CEM and DCE-MRI. The lesions were retrospectively analyzed with radiomic and artificial intelligence approaches. Forty-eight textural metrics were extracted, and univariate and multivariate analyses were performed: non-parametric statistical test, receiver operating characteristic (ROC) and machine learning classifiers. Results: Considering the single metrics extracted from CEM, the best predictors were KURTOSIS (area under ROC curve (AUC) = 0.71) and SKEWNESS (AUC = 0.71) calculated on late MLO view. Considering the features calculated from DCE-MRI, the best predictors were RANGE (AUC = 0.72), ENERGY (AUC = 0.72), ENTROPY (AUC = 0.70) and GLN (gray-level nonuniformity) of the gray-level run-length matrix (AUC = 0.72). Considering the analysis with classifiers and an unbalanced dataset, no significant results were obtained. After the balancing and feature selection procedures, higher values of accuracy, specificity and AUC were reached. The best performance was obtained considering 18 robust features among all metrics derived from CEM and DCE-MRI, using a linear discriminant analysis (accuracy of 0.84 and AUC = 0.88). Conclusions: Classifiers, adjusted with adaptive synthetic sampling and feature selection, allowed for increased diagnostic performance of CEM and DCE-MRI in the differentiation between benign and malignant lesions.

Direct ink writing of silica-bonded calcite scaffolds from preceramic polymers and fillers

Silica-bonded calcite scaffolds have been successfully 3D-printed by direct ink writing, starting from a paste comprising a silicone polymer and calcite powders, calibrated in order to match a SiO₂/CaCO₃ weight balance of 35/65. The scaffolds, fabricated with two slightly different geometries, were first cross-linked at 350 °C, then fired at 600 °C, in air. The low temperature adopted for the conversion of the polymer into amorphous silica, by thermo-oxidative decomposition, prevented the decomposition of calcite. The obtained silica-bonded calcite scaffolds featured open porosity of about 56%-64% and compressive strength of about 2.9-5.5 MPa, depending on the geometry. Dissolution studies in SBF and preliminary cell culture tests, with bone marrow stromal cells, confirmed the in vitro bioactivity of the scaffolds and their biocompatibility. The seeded cells were found to be alive, well anchored and spread on the samples surface. The new silica-calcite composites are expected to be suitable candidates as tissue-engineering 3D scaffolds for regeneration of cancellous bone defects.

A 3-year evaluation of the TCu380Ag and the Cu-7

The TCu380Ag and the Cu-7 intrauterine devices (IUDs) were evaluated in a randomized comparative clinical trial. A total of 198 women who had not recently been pregnant entered the trial in Manila, Philippines and were followed-up through 3 years postinsertion. The 36-month follow-up rates were impressively high at 80.3 for TCu 380A users and 76.7 for users of the Cu-7. Although the two IUDs demonstrated statistically similar termination rates, the findings suggest a higher efficacy for the TCu380Ag. Gross cumulative life-table pregnancy rates were 0.0 and 4.5 for the TCu380Ag and Cu-7, respectively, at 3 years. Overall 3-year continuation rates were 74.3 and 64.9 for users of the respective devices.

New Deployable Expandable Electrodes in the Electroporation Treatment in a Pig Model: A Feasibility and Usability Preliminary Study

The aim of the study is to evaluate the usability aspects of new deployable, expandable, electrode prototypes, in terms of suitability solutions for laparoscopic applications on the liver, endoscopic trans-oral and trans-anal procedures, electroporation segmentation in several steps, mechanical functionality (flexibility, penetrability), visibility of the electrode under instrumental guidance, compatibility of the electrode with laparoscopic/endoscopic accesses, surgical instruments, and procedural room and safety compatibility. The electroporation was performed on an animal model (Sus Scrofa Large White 60 kg) both in laparoscopy and endoscopy, under ultrasound guidance, and in open surgery. Electrodes without divergence, with needles coming out straight, parallel to each other, and electrodes with peripheral needles (four needles), diverging from the electrode shaft axis (electrode with non-zero divergence) have been tested. To cause an evaluable necrosis effect, the number of electrical pulses was increased to induce immediate liver cell death. Histological samples were analyzed by staining with Haematoxylin/Eosin or by immunohistochemical staining to confirm complete necrosis. The prototypes of expandable electrodes, tested in laparoscopy and endoscopy and in open surgery, respectively, are suitable in terms of usability, electroporation segmentation in several steps, mechanical functionality (flexibility, penetrability), visibility under instrumental guidance, compatibility with laparoscopic/endoscopic accesses, surgical instruments and procedural room safety, patient safety (no bleeding and/or perforation), and treatment efficacy (adequate ablated volume). Electroporation treatment using new deployable expandable electrode prototypes is safe and feasible. Moreover, electrode configurations allow for a gradual increase in the ablated area in consecutive steps, as confirmed by histology and immunohistochemistry.

Radiomics Metrics Combined with Clinical Data in the Surgical Management of Early-Stage (cT1-T2 N0) Tongue Squamous Cell Carcinomas: A Preliminary Study

Objective: To predict the risk of metastatic lymph nodes and the tumor grading related to oral tongue squamous cell carcinoma (OTSCC) through the combination of clinical data with radiomics metrics by computed tomography, and to develop a supportive approach in the management of the lymphatic cervical areas, with particular attention to the early stages (T1−T2). Between March 2016 and February 2020, patients with histologically confirmed OTSCC, treated by partial glossectomy and ipsilateral laterocervical lymphadenectomy and subjected to computed tomography (CT) before surgery, were identified by two centers: 81 patients (49 female and 32 male) with 58 years as the median age (range 19−86 years). Univariate analysis with non-parametric tests and multivariate analysis with machine learning approaches were used. Clinical, hematological parameters and radiological features extracted by CT were considered individually and in combination. All clinical parameters showed statistically significant differences (p < 0.05) for the Kruskal−Wallis test when discriminating both the tumor grading and the metastatic lymph nodes. DOI, PLR, SII, and SIRI showed an accuracy of 0.70 (ROC analysis) when identifying the tumor grading, while an accuracy ≥ 0.78 was shown by DOI, NLR, PLR, SII, and SIRI when discriminating metastatic lymph nodes. In the context of the analysis of radiomics metrics, the original_glszm_HighGrayLevelZoneEmphasis feature was selected for identifying the tumor grading (accuracy of 0.70), while the wavelet_HHH_glrlm_LowGrayLevelRunEmphasis predictor was selected for determining metastatic lymph nodes (accuracy of 0.96). Remarkable findings were also obtained when classifying patients with a machine learning approach. Radiomics features alone can predict tumor grading with an accuracy of 0.76 using a logistic regression model, while an accuracy of 0.82 can be obtained by running a CART algorithm through a combination of three clinical parameters (SIRI, DOI, and PLR) with a radiomics feature (wavelet_LLL_glszm_SizeZoneNonUniformityNormalized). In the context of predicting metastatic lymph nodes, an accuracy of 0.94 was obtained using 15 radiomics features in a logistic regression model, while both CART and CIDT achieved an asymptotic accuracy value of 1.00 using only one radiomics feature. Radiomics features and clinical parameters have an important role in identifying tumor grading and metastatic lymph nodes. Machine learning approaches can be used as an easy-to-use tool to stratify patients with early-stage OTSCC, based on the identification of metastatic and non-metastatic lymph nodes.

Glass-ceramics from vitrified sewage sludge pyrolysis residues and recycled glasses

Pyrolysis of urban plant sewage sludge has been demonstrated to be an effective way to produce fuel gas. However, a complete disposal of this particular waste is not achieved if the solid residues from the treatment are not considered. In this paper we discuss the feasibility an integrated pyrolysis/vitrification/sintering approach, aimed at a "full" disposal: the pyrolysis residues are first converted into a glass, then transformed into glass-ceramics, by simple viscous flow sintering treatments, with or without additions of inexpensive recycled glasses and kaolin clay. The obtained products were demonstrated to constitute an alternative to natural stones, in terms of both mechanical strength and chemical stability.

Neoadjuvant chemoradiotherapy and surgery as treatment for oral maxillary squamous cell carcinoma in a dog

A gingival maxillary squamous cell carcinoma was diagnosed in a 12-year-old male Yorkshire Terrier. After a complete diagnostic work-up, including a computed tomography scan, the tumour was staged as T3bN1aM0 and considered non-resectable at presentation. The combination of neoadjuvant megavoltage radiotherapy and neoadjuvant and adjuvant chemotherapy with carboplatin and doxorubicin decreased the size of the tumour, allowing for surgery. The dog was free from local disease for 421 days after which it was euthanased at the owners' request.

Design and Characterization of a Minimally Invasive Bipolar Electrode for Electroporation

OBJECTIVE

To test a new bipolar electrode for electroporation consisting of a single minimally invasive needle.

METHODS

A theoretical study was performed by using Comsol Multiphysics^® software. The prototypes of electrode have been tested on potatoes and pigs, adopting an irreversible electroporation protocol. Different applied voltages and different geometries of bipolar electrode prototype have been evaluated.

RESULTS

Simulations and pre-clinical tests have shown that the volume of ablated area is mainly influenced by applied voltage, while the diameter of the electrode had a lesser impact, making the goal of minimal-invasiveness possible. The conductive pole's length determined an increase of electroporated volume, while the insulated pole length inversely affects the electroporated volume size and shape; when the insulated pole length decreases, a more regular shape of the electric field is obtained. Moreover, the geometry of the electrode determined a different shape of the electroporated volume. A parenchymal damage in the liver of pigs due to irreversible electroporation protocol was observed.

CONCLUSION

The minimally invasive bipolar electrode is able to treat an electroporated volume of about 10 mm in diameter by using a single-needle electrode. Moreover, the geometry and the electric characteristics can be selected to produce ellipsoidal ablation volumes.

Impact of smoking habit on platelet reactivity in a cohort of patients admitted due to an acute coronary syndrome

Background

Several pharmacodynamic studies have shown the impact of smoking habit on platelet reactivity; with a reduction on platelet aggregation. Wether this inhibition in platelet reactivity is due to tobacco effects in platelet signaling pathways or due to a pharmacodynamic interaction with antiplatelet therapies is not well stablished.

Purpose

Our aim was to study the influence of smoking habit in platelet reactivity and in the response to P2Y12 inhibitors.

Methods

Patients admitted in four tertiary care hospitals due to an acute coronary syndrome that undergone percutaneous coronary intervention (PCI) were consecutively and prospectively recruited. All the patients received dual antiplatelet therapy with aspirin and a P2Y12 inhibitor following current European Guidelines. Platelet function was assessed at day 1 and day 30 post-PCI by VerifyNow P2Y12, VASP (Vasodilator-stimulated phosphoprotein) y MEA (Multiple electrode aggregometry).

Results

A total of 1000 patients were enrolled, of whom 12 had to be excluded due to inaccurate processing of blood samples. 372 patients (37,6%) had smoking habit. Non-smoking patients showed higher prevalence of high blood pressure [423 (68.7%) vs 196 (52.7%)] and diabetes mellitus [213 (34.6%) vs 81 (21.8%)]. Smoking patients were younger [57.3 (9,6) years old vs 68.4 (11.1)], with higher incidence of acute coronary syndrome with ST segment elevation [184 patients (49,5%) vs 241 (39.1%), p&lt;0,001]. There were no differences in platelet function at day 1. When analysing platelet function 30 days post-PCI, a lower inhibition of platelet reactivity in non-smoking patients as compared with smoking patients was observed in those treated with clopidogrel, with higher prevalence of clopidogrel-resistance in non-smoking patients (VerifyNow, 51,2% prevalence of high platelet reactivity in non-smoking patients vs 34,9% 30 days after PCI, p=0,023). On the other hand, smoking patients that received ticagrelor did not show any differences. Patients with smoking habit treated with prasugrel showed a lower response of borderline statistical significance.

Conclusion

Smoking habit was associated with a lower response to prasugrel of borderline significance, and with higher response to clopidogrel, according with previous studies suggesting a pharmacodynamics interaction between tobacco use and P2Y12 inhibitors.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fondo de Investigaciones Sanitarias (FIS)

P5613Proportional relationship between early mobilization of bone marrow progenitor cells and the extent of vascular injury during coronary stenting: insights on the role of systemic mechanisms of vascular

Background

The role of circulating progenitor cells (CPCs) on vascular repair after everolimus-eluting stent (EES) implantation is largely unknown.

Objectives

The aim of the study was to investigate the quantitative and temporal variations of CPCs levels after EES implantation, and its relationship with the degree of peri-procedural vascular damage, stent healing and neointimal hyperplasia, as measured by optical coherence tomography (OCT).

Methods

In a consecutive series of patients with stable coronary artery disease undergoing stent implantation CPC subpopulations (CD34+/CD45low, CD133+/CD45low, CD34/KDR/CD45low, CD133/KDR/CD45low) were evaluated using a flow cytometry technique at baseline, 1 and 4 weeks. OCT evaluation was performed immediately after stent implantation to quantify stenting-related injury, and at 9-month follow-up to assess mid-term vascular response.

Results

Twenty patients (mean age 66±9 years; 80%male) with 24 stenoses treated with EES were included in the study. Vascular injury score was associated with the increase of CD133+/KDR/CD45 low at 1-week (β0.28 [95% CI0.15; 0.41], p<0.001) and with the maximum neointimal thickness at 9-month follow-up (β0.008 [95% CI-0.0004; 0.002]:p=0.04). Mean neointimal area at 9-month was associated with the increase in the number of CD34+/CD45low at 1 week (β0.029 [95% CI0.025;-0.033]; p<0.0001). Inverse relationships between the number of uncoated and apposed struts at 9-month and the 1-week delta values of CD34/KDR/CD45low and CD133/KDR/CD45low (β-4.49 [95% CI-8.17;-0.82]; p=0.017 and β −12.53 [95% CI: −22.17; −2.90]; p=0.011, respectively) were also found.

Conclusion

Long-term vascular healing after EES implantation is modulated by early changes in levels of CPC subpopulations. This systemic response is proportional to the extent of vessel wall injury. Early mobilization of CPCs influences mid-term strut coverage and the development of neointimal hyperplasia.

Acknowledgement/Funding

Dr Jimenez-Quevedo is a recipient of the ISCIII (Instituto de Salud Carlos III) grant “Fondo de Investigaciόn Sanitaria” (PI11/00299) to perform this

Is “one size fits all” anti-aggregation really effective? Variability in the response to P2Y12 receptor inhibitors in obese patients

Background

Different “ex vivo” studies have shown both a greater platelet activation and higher rates of resistance to clopidogrel in obese patients. Although there is less evidence, less prasugrel activity has also been observed in these patients. Our aim was to study the variability of the response to clopidogrel, ticagrelor and prasugrel in obese patients, defined as a body mass index ≥30.

Methods

Prospective, multicenter, observational, pharmacodynamic study, conducted in a Spanish population of patients with an acute coronary syndrome (ACS) treated with percutaneous coronary intervention (PCI) and double anti-aggregation with acetylsalicylic acid and a P2Y12 receptor inhibitor. Platelet function tests were performed the morning after the ICP and 30 days after it, including: 1) VerifyNow P2Y12 assay; 2) multiple electrode aggreometry (Multiplate); and 3) VASP analysis.

Results

Of the total patients included (988), 300 were obese (30.3%). The obese group was younger (62.8±12 years vs 64.9±12), had a higher incidence of arterial hypertension (76.3% vs. 56.7%), diabetes mellitus (35% vs. 27.5%); and lower incidence of chronic kidney disease (7.7% vs. 17%). There were no differences in the acute phase (day 1 after PCI) in the pharmacodynamic response to any of the P2Y12 inhibitors used. After 30 days, greater platelet aggregation (decreased response) was documented in obese patients treated with prasugrel according to VASP tests (PRI in non-obese 23.9±13% vs. 30.4±14.7% in obese, p 0.035) and MEA (area under the aggregation units curve in non-obese 251.7±104.1 vs 320±166.7 in obese, p 0.007) and a numerical trend with VerifyNow. A trend in the same direction was also observed in patients treated with clopidogrel that did not reach statistical significance with all the platelet function tests used. No differences were observed in the ticagrelor group.

Conclusion

Obese patients with an ACS treated with PCI have a worse response to thienopyridines than non-obese patients in the maintenance phase of antiaggregant treatment, while the response to ticagrelor is not affected by obesity. Completing the clinical follow-up proposed by the registry is necessary to know if these differences have an implication in cardiovascular events.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fondo de Investigaciones Sanitarias (FIS)

Effects of intravenous lysine acetylsalicylate versus oral aspirin on platelet responsiveness in patients with ST-segment elevation myocardial infarction

Background

Prasugrel and ticagrelor, new P2Y12-ADP receptor antagonists, are associated with greater pharmacodynamic inhibition and reduction of cardiovascular events in patients with an acute coronary syndrome. However, evidence is lacked about the effects of achieving faster and stronger cyclooxygenase inhibition with intravenous lysine acetylsalicylate (LA) compared to oral aspirin on prasugrel inhibited platelets in patients with an ST-segment elevation myocardial infarction (STEMI).

Methods

This is a prospective, randomized, multicenter, open platelet function study conducted. STEMI patients were randomly assigned to receive a loading dose (LD) of intravenous LA 450mg plus oral ticagrelor 180mg, or LD of aspirin 300mg plus ticagrelor 180mg orally. Platelet function was evaluated at baseline, 30 min, 1h, and 24h using multiple electrode aggregometry and vasodilator-stimulated phosphoprotein phosphorylation (VASP). The primary endpoint of the study is the inhibition of platelet aggregation after arachidonic acid (AA) 1.5mM at 30 min. Secondary endopoints are the inhibition of platelet aggregation after AA baseline and at 1h, and 24h, and measurement of aggregation with other platelet test (ADP, collagen and VASP).

Results

A total of 32 STEMI patients were randomized (16 LA, 16 aspirin). The inhibition of platelet aggregation after AA 1.5 mM at 30 min was greater in subjects treated with LA compared with aspirin: 166 vs. 412 respectively, p=0.001. This differential effect was observed at 1 hour (p=0.01), but not at 24 hours. Subjects treated with LA presented less variability and faster and greater inhibition of platelet aggregation with AA compared with aspirin (Figure 1).

Conclusions

The administration of intravenous LA resulted in a significantly reduction of platelet reactivity compared to oral aspirin on ticagrelor inhibited platelets in patients with STEMI. Loading dose of LA achieves an earlier platelet inhibition, and with less variability than aspirin.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by the CTU-SCReN (Clinical Trial Unit – Spanish Clinical Research Network) from San Carlos University Hospital (Madrid, Spain), financed by the ISCII (Project PI16/00191)