Déterminants des niveaux sériques d'interleukine-6 chez les patients avec un cancer de la sphère oto-rhino-laryngologique

Contexte Des travaux antérieurs ont montré que l'interleukine-6 circulante (IL-6) était un facteur prédicteur significatif de la survenue de seconds cancers primaires (SCP) chez les patients atteints d'un cancer de la sphère oto-rhino-laryngologique (ORL). Objectif Le but de cette étude était d'identifier les facteurs associés aux niveaux sériques d'IL-6 chez les patients atteints de cancer ORL de stade I-II. Méthodes Cette étude a été réalisée dans le cadre d'un essai de chimioprévention de phase III. Un échantillon de sérum a été obtenu avant tout traitement auprès de 527 des 540 patients présentant un cancer ORL recrutés pour participer à l'essai clinique. L'IL-6 a été mesurée par immunométrie chimioluminescente. Les caractéristiques sociodémographiques et cliniques des patients, leurs habitudes de vie et les caractéristiques de leur tumeur ont été évaluées. Les facteurs indépendamment associés aux niveaux sériques d'IL-6 ont été identifiés en utilisant un modèle de régression linéaire multiple. Résultats La concentration médiane d'IL-6 dans le sérum était de 3,1 ng/L (intervalle interquartile : 2,20-4,40). L'analyse multivariée a permis d’identifier huit facteurs significativement associés à l'IL-6 (P ≤ 0,05) : l’âge, le sexe, le statut matrimonial, l’indice de masse corporelle, le tabagisme, l’indice de comorbidités, le score de performance de Karnofsky et le site tumoral. Chez les fumeurs, les taux sériques d'IL-6 augmentaient de façon dose-dépendante avec la durée du tabagisme (p de tendance = 0,03) et avec le nombre de paquets-années consommés (p de tendance = 0,03). Conclusion Ces résultats ont montré que plusieurs facteurs de risque standards de SCP sont aussi associés aux taux circulants d'IL-6. Ceci suggère que l'effet de ces facteurs sur la survenue de SCP pourrait être médié par un processus inflammatoire. De plus, nous avons montré une relation doseréponse avec la quantité ou la durée du tabagisme, suggérant un rôle causal du tabac dans la production d'IL-6.Background In a previous work, we reported that circulating interleukin-6 (IL-6) significantly improves outcome prediction for second primary cancer (SPC) in head and neck cancer (HNC) patients. Objective The purpose of this study was to identify factors associated with IL-6 serum levels in patients with stage I or II HNC. Methods This study was conducted as part of a phase III chemoprevention trial. A pretreatment serum sample was obtained from 527 of the 540 HNC patients recruited in the trial. IL-6 was measured on an Immulite analyzer with chemiluminescent immunometric assay (Siemens Diagnostics). Patients’ sociodemographic and medical characteristics, lifestyle habits and cancer characteristics were evaluated before radiation therapy. Factors independently associated with IL-6 levels were identified using the multiple linear regression. Results The median of IL-6 serum level was 3.1 ng/L (Interquartile range: 2.20-4.40). In the multivariate analysis, eight factors were significantly associated with IL-6 (P ≤ 0.05): age, sex, marital status, body mass index (BMI), smoking, comorbidity index, Karnofsky performance status, and cancer site. In cigarette smokers, IL-6 serum levels increased with longer durations of cigarette smoking (p-value for trend = 0.03) and with the number of pack-years consumed (p-value for trend = 0.03). Conclusion These results showed that several standard risk factors of SPC, such as age, BMI and smoking status, are associated with circulating IL-6 levels. This suggests that the effect of these factors on the occurrence of SPC might be mediated by an inflammatory process. Moreover, we have shown a dose-response relationship with the quantity smoked or the duration of smoking suggesting a causal role of tobacco in IL-6 production

Expression et localisation de la connexine 43 dans le glioblastome : implication pour la thérapie génique

L’effet de proximité est essentiel à la réussite de la stratégie thymidine kinase (HSV-tk)/ganciclovir (GCV) dans le traitement du cancer. Cette propriété correspond au transfert de GCV phosphorylé des cellules tumorales HSV-tk+ vers les cellules tumorales HSV-tk–, et est essentiellement médiée par les jonctions gap (JGs) constituées de molécules de connexine (Cx). Une perte d’expression et/ou une localisation périnucléaire des connexines est souvent décrite dans les tumeurs, ce qui pourrait conduire, en théorie, à une diminution de l’efficacité du traitement HSV-tk/GCV. L’approche HSV-tk/GCV a été testée au cours d’essais cliniques pour le traitement du glioblastome bien que l’expression de la Cx43 (principal constituant des JGs dans les astrocytes) ne soit parfaitement définie. Au cours de mes travaux, l’expression de la Cx43, sa localisation et sa fonctionnalité ont été étudiées dans des lignées établies, des biopsies et des cultures primaires de glioblastome. Dans les trois lignées immortalisées de glioblastome étudiées, la Cx43 se retrouve essentiellement localisée dans les endosomes et les lysosomes comparativement aux cellules HeLa/Cx43 qui présentent une localisation membranaire de la Cx43. Des JGs ont été observées dans la lignée U87, mais très peu dans les lignées SKI-1 et U251. De façon surprenante, les lignées SKI-1 et U87 présentent une capacité jonctionnelle supérieure à celle des cellules HeLa/Cx43. De plus, un important effet de proximité a pu être mesuré dans les cellules SKI-1 et U87 suite au traitement par le GCV. L’utilisation d’un inhibiteur spécifique de la perméabilité des JGs a confirmé que l’effet de proximité induit dans ces lignées est principalement dû aux JGs. De plus, la transfection d’un mutant dominant négatif de la Cx43 ou de siARN spécifiques des ARNm de la Cx43 a permis d’identifier la Cx43 comme le principal constituant des JGs dans ces lignées de glioblastome. L’expression de la Cx43 a été mesurée sur soixante-quatorze biopsies de glioblastome. Si son expression est souvent plus faible que dans le tissu sain, seulement 23% des échantillons sont dépourvus de Cx43. Huit lignées primaires ont été dérivées de résections de patients, et sept d’entre elles expriment la Cx43, cependant à différents niveaux d’intensité. Quatre lignées démontrent une localisation cytoplasmique de la Cx43. Malgré la localisation cytoplasmique prédominante de la Cx43, ces cellules sont capables de communiquer entre elles efficacement comme l’essai de double marquage en cytométrie de flux l’a démontré. Un vecteur lentiviral contenant le gène HSV-tk a été construit afin de mener les tests d’effet de proximité. Il a ainsi été mis en évidence que quelle que soit la localisation de la Cx43, l’effet de proximité est significatif dans toutes les lignées exprimant la Cx43 et inexistant lorsque la Cx43 n’est pas présente. Ces résultats démontrent que la Cx43 est exprimée dans la majorité des glioblastomes. La Cx43 peut être exprimée dans les lignées établies et les lignées primaires de glioblastome au niveau de la membrane plasmique ou dans le cytoplasme. Cette localisation aberrante ne bloque pas le transfert intercellulaire de molécules, ce qui suggère que les rares JGs présentes à la surface sont hautement fonctionnelles. Ces résultats indiquent que l’approche HSV-tk/GCV est un candidat valable pour le traitement du glioblastome, contrairement à d’autres tumeurs pour lesquelles la perte d’expression de Cx est bien documentée. Il serait ainsi intéressant que l’expression de la Cx43 soit étudiée dans les biopsies utilisées lors du diagnostic et constitue ainsi un prérequis pour le recrutement des patients lors d’essais cliniques.The bystander effect is essential to the success of the Herpes simplex virus thymidine kinase (HSV-tk)/ganciclovir (GCV) strategy for cancer therapy. It consists of the transfer of phosphorylated GCV from HSV-tk+ cells to neighboring HSV-tk- cells, and it is mainly mediated via gap junctions that are made up of connexin molecules (Cx). Down-regulation and/or perinuclear localization of Cxs are common in tumors, and in theory it should decrease the efficacy of the HSV-tk/GCV treatment. The HSV-tk/GCV approach has been tested in glioblastoma patients although the status of Cx43 expression (the Cx member expressed in astrocytes) is unclear in this tumor type. In this study, we have carefully evaluated the Cx43 expression, specific localization and functionality in glioblastoma cell lines, biopsies and primary glioblastoma cell cultures. In the glioblastoma cell lines studied (SKI-1, U251 and U87), Cx43 accumulated mainly in late endosomes and lysosomes as compared to HeLa/Cx43 transfected cells that displayed Cx43 at the cellular membrane. Gap junctions were observed in U87 cells, but very few or rare plaques were present at the surface of SKI-1 and U251 cells, respectively. Surprisingly, calcein, a dye commonly used to assess the functionality of gap junctions, was able to diffuse more efficiently within U87 and SKI-1 cells than in HeLa/Cx43 cells. Furthermore, a strong bystander effect was mediated by HSV-tk+ SKI-1 and U87 cells treated with GCV. The use of a specific inhibitor of gap junction permeability, confirmed that the bystander effect in these cell lines was mainly due to gap junctions. Moreover, transfection of a Cx43 dominant negative mutant and specific siRNA against Cx43 mRNA defined this Cx subtype as the major component of gap junctions in these glioblastoma cell lines. The level of Cx43 expression was next assessed in seventy-four glioblastoma biopsies. Cx43 expression was mainly lower than in normal tissue, but only 23% of the glioblastoma samples studied lacked Cx43 expression. Eight glioblastoma primary cultures were derived from surgical resection, and seven of them expressed Cx43, although at different levels. A cytoplasmic localization of Cx43 was also observed in four primary cultures. Despite this predominant intracellular accumulation of Cx43, cells were able to communicate in an efficient manner as demonstrated with a dye transfer assay. A lentiviral vector containing HSV-tk has been constructed and bystander effect experiments with these primary glioblastoma cells were carried out. We noticed that the bystander effect was significative in primary cells expressing Cx43 wherever the Cx43 was localized, and no bystander effect was detected in cells without Cx43 expression. Our results indicate that Cx43 is expressed in the majority of glioblastomas. Cx43 can be found in glioblastoma cell lines and primary cultures at the cell surface, but also in perinuclear areas. This aberrant localization of Cx43 did not prevent the diffusion of molecules, suggesting that the few gap junction plaques present in glioblastoma cells are highly functional. These results suggest that glioblastoma is a suitable candidate for the HSV-tk/GCV approach contrary to some other tumor types in which the lack of Cx has been well documented. According to these results, the level of Cx43 should be tested in patient biopsies used for diagnostics and considered for patient enrollment in clinical trials

Occipital nerve stimulation for non-migrainous chronic headaches : a systematic review protocol

Background: Defined as a headache lasting at least 15 days per month, chronic headache is reported by 3% of the general population, and a substantial proportion of them are refractory to current therapies. Occipital nerve stimulation (ONS) is a treatment option, but is still considered as a last resort treatment especially because of its invasive nature and the cost associated. Some reviews reported a limited efficacy of ONS for the treatment of migraines, with a high risk of complications. However, results reporting its efficacy and safety on other headache disorders are unclear. The aim of this review is to assess the efficacy and safety of ONS in regards to non-migrainous chronic headaches. Methods: We will conduct a systematic review and meta-analysis of studies evaluating the use of ONS in comparison to sham stimulation or the best available treatment in patients with chronic headache. MEDLINE, CINHAL, EMBASE, PsycINFO, ECRI Institute Library, WIKISTIM, the Cochrane Library databases, and clinical trial registries will be searched for eligible studies. The review will include adult patients diagnosed with chronic headache excluding migraine. Two independent reviewers will process to the screening of studies according to titles, abstracts, and then full texts. The primary outcome is the overall reduction of head pain severity. The secondary outcomes are rates of reduction in the severity of head pain, headache frequency, and duration, use of medication, impairment, quality of life, healthcare utilization, return to work, and adverse events. Extracted data will include patients’ and procedure characteristics, details on comparative treatment or sham, and clinical outcomes. The risk of bias of the studies will be also independently assessed using the Cochrane risk of bias tools. Discussion: This systematic review will allow us to better evaluate the potential role of ONS for the treatment of patients with chronic headache that are refractory to less invasive therapies. It will help to determine the degree of safety of ONS. Moreover, it will help to design and conduct future randomized controlled trials focused on patients who may better respond to such treatmen

Studies on the internalization mechanisms of cationic cell-penetrating peptides.

A great deal of data has been amassed suggesting that cationic peptides are able to translocate into eucaryotic cells in a temperature-independent manner. Although such peptides are widely used to promote the intracellular delivery of bioactive molecules, the mechanism by which this cell-penetrating activity occurs still remains unclear. Here, we present an in vitro study of the cellular uptake of peptides, originally deriving from protegrin (the SynB peptide vectors), that have also been shown to enhance the transport of drugs across the blood-brain barrier. In parallel, we have examined the internalization process of two lipid-interacting peptides, SynB5 and pAntp-(43–58), the latter corresponding to the translocating segment of the Antennapedia homeodomain. We report a quantitative study of the time- and dose-dependence of internalization and demonstrate that these peptides accumulate inside vesicular structures. Furthermore, we have examined the role of endocytotic pathways in this process using a variety of metabolic and endocytosis inhibitors. We show that the internalization of these peptides is a temperatureand energy-dependent process and that endosomal transport is a key component of the mechanism. Altogether, our results suggest that SynB and pAntp-(43–58) peptides penetrate into cells by an adsorptive-mediated endocytosis process rather than temperature-independent translocation

Effect of aneurysm size on procedure-related rupture in patients with subarachnoid hemorrhage treated with coil occlusion

Objective: Procedure-related rupture is one of the most feared complications in treating patients with cerebral aneurysm. The primary aim of this study was to estimate the effect of aneurysm size on procedure-related rupture. We also estimated its effect on peri-procedural thromboembolic events. Methods: This observational study was conducted using routinely-collected health data on patients admitted for subarachnoid hemorrhage and treated with aneurysm coil occlusion in the CHU de Québec — Enfant-Jésus hospital from January 1st, 2000 until sample size was reached. Patients were identified from the Discharge Abstract Database using the Canadian Classification of Health codes. Assessment of complications was blind to aneurysm size. Logistic regression models were performed to test associations between aneurysm size and procedure-related rupture or peri-procedural thromboembolic events, and between both procedure-related rupture and thromboembolic events and patients' outcomes. Results: This study included 532 aneurysms treated with coil occlusion in 505 patients. Procedure-related rupture occurred in 34 patients (6.7%) and thromboembolic events in 53 (10.5%) patients. Aneurysms of 2 to 3 mm inclusively were not more significantly associated with procedure-related rupture or thromboembolic events than those larger than 3 mm (OR 1.02, 95% CI: 0.9–1.16, p = 0.78 and OR 1.06, 95% CI: 0.96–1.17, p = 0.3, respectively). However, procedure-related rupture had a significant effect on patient mortality (OR 3.86, 95% CI: 1.42–10.53, p < 0.01). Conclusions: Very small aneurysm size should not preclude aneurysm coil occlusion. Every measure should be taken to prevent procedure-related rupture as it is strongly associated with higher mortality

Spinal cord stimulation in the treatment of neuropathic pain: Current perspectives of indications, cost-effectiveness, complications and results

Introduction: The spinal cord stimulation (SCS) has been described as a valuable neuromodulating procedure in the management of chronic and medically untreated neuropathic pain. Although, many studies have discussed the use of this technique, a question still remains regarding its efficacy in different medical conditions with different etiology in the long term. The aim of this paper is to discuss the risks, complications, cost-effectiveness and results of SCS in patients affected by chronic neuropathic pain based on the comprehensive literature review. Methods: Bibliographic search of references from 1950 to 2016 using the databases MEDLINE, LILACS, SciELO, PubMed, and applied language as selection criteria, choosing preferably recent articles written in Portuguese, Spanish or English. Results: Based on literature review, SCS is a safe, reversible, adjustable and nondestructive surgical procedure demonstrating a significant effect in the reduction of pain intensity and improvement in quality of life in these patients. Furthermore, in spite of the initial high cost to its application, SCS has been associated with lower rates of complications and high rates of cost-effectiveness when compared to standard therapies. Conclusion: Although used in medical conditions with different etiology, the procedure is still an effective and a cost-effective approach to neuropathic pain, mainly in patients affected by failed back pain syndrome (FBSS) and complex regional pain syndrome (CRPS)

Examining the Duration of Carryover Effect in Patients With Chronic Pain Treated With Spinal Cord Stimulation (EChO Study):An Open, Interventional, Investigator-Initiated, International Multicenter Study

Objectives: Spinal cord stimulation (SCS) is a surgical treatment for severe, chronic, neuropathic pain. It is based on one to two lead(s) implanted in the epidural space, stimulating the dorsal column. It has long been assumed that when deactivating SCS, there is a variable interval before the patient perceives the return of the pain, a phenomenon often termed echo or carryover effect. Although the carryover effect has been problematized as a source of error in crossover studies, no experimental investigation of the effect has been published. This open, prospective, international multicenter study aimed to systematically document, quantify, and investigate the carryover effect in SCS. Materials and Methods: Eligible patients with a beneficial effect from their SCS treatment were instructed to deactivate their SCS device in a home setting and to reactivate it when their pain returned. The primary outcome was duration of carryover time defined as the time interval from deactivation to reactivation. Central clinical parameters (age, sex, indication for SCS, SCS treatment details, pain score) were registered and correlated with carryover time using nonparametric tests (Mann-Whitney/Kruskal-Wallis) for categorical data and linear regression for continuous data. Results: In total, 158 patients were included in the analyses. A median carryover time of five hours was found (interquartile range 2.5;21 hours). Back pain as primary indication for SCS, high-frequency stimulation, and higher pain score at the time of deactivation were correlated with longer carryover time. Conclusions: This study confirms the existence of the carryover effect and indicates a remarkably high degree of interindividual variation. The results suggest that the magnitude of carryover may be correlated to the nature of the pain condition and possibly stimulation paradigms. Clinical Trial Registration: The Clinicaltrials.gov registration number for the study is NCT03386058.</p

Examining the Duration of Carryover Effect in Patients With Chronic Pain Treated With Spinal Cord Stimulation (EChO Study):An Open, Interventional, Investigator-Initiated, International Multicenter Study

Objectives: Spinal cord stimulation (SCS) is a surgical treatment for severe, chronic, neuropathic pain. It is based on one to two lead(s) implanted in the epidural space, stimulating the dorsal column. It has long been assumed that when deactivating SCS, there is a variable interval before the patient perceives the return of the pain, a phenomenon often termed echo or carryover effect. Although the carryover effect has been problematized as a source of error in crossover studies, no experimental investigation of the effect has been published. This open, prospective, international multicenter study aimed to systematically document, quantify, and investigate the carryover effect in SCS. Materials and Methods: Eligible patients with a beneficial effect from their SCS treatment were instructed to deactivate their SCS device in a home setting and to reactivate it when their pain returned. The primary outcome was duration of carryover time defined as the time interval from deactivation to reactivation. Central clinical parameters (age, sex, indication for SCS, SCS treatment details, pain score) were registered and correlated with carryover time using nonparametric tests (Mann-Whitney/Kruskal-Wallis) for categorical data and linear regression for continuous data. Results: In total, 158 patients were included in the analyses. A median carryover time of five hours was found (interquartile range 2.5;21 hours). Back pain as primary indication for SCS, high-frequency stimulation, and higher pain score at the time of deactivation were correlated with longer carryover time. Conclusions: This study confirms the existence of the carryover effect and indicates a remarkably high degree of interindividual variation. The results suggest that the magnitude of carryover may be correlated to the nature of the pain condition and possibly stimulation paradigms. Clinical Trial Registration: The Clinicaltrials.gov registration number for the study is NCT03386058.</p

Bystander effect in glioblastoma cells with a predominant cytoplasmic localization of connexin 43

Herpes simplex virus thymidine kinase (TK) gene transfer followed by ganciclovir (GCV) administration is an approach investigated for glioblastoma treatment. The bystander effect (BE) enhances the cytotoxic effect of this strategy by allowing the diffusion of phosphorylated GCV from TK-expressing cells toward neighboring TK negative cells. This transfer of toxic metabolites is mainly mediated via gap junctions that are composed of connexins. Downregulation and/or cytoplasmic localization of connexins are common in tumors, and should be detrimental to the success of the TK/GCV strategy. In this study, we investigated the level of expression, the localization and the functionality of connexin43 (Cx43) in three glioblastoma cell lines. We showed that Cx43 was predominantly located in lysosomes and late endosomes, with only few gap junctions present at the cell surface. Surprisingly, the gap-junctional intercellular communication (GJIC) and the BE capacity were preserved, and in two of the cell lines analyzed, it was at least twice as high as compared to a control HeLa transfectant that expresses high levels of Cx43 at the cell membrane. Experiments performed in the presence of a-glycyrrhetinic acid or small interfering RNA confirmed that Cx43 was responsible for the GJIC and the BE. Our results indicate for the first time that the very limited numbers of gap junctions present in glioblastoma cells are highly functional. We thus conclude that the TK/GCV strategy is still a valuable therapeutic option to be developed for the treatment of glioblastoma patients

Effects of tonic spinal cord stimulation on external mechanical and thermal stimuli perception using quantitative sensory testing: a multicenter stimulation ON-OFF study on chronic pain patients

Objectives: Tonic spinal cord stimulation (SCS) is currently used to treat neuropathic pain. With this type of stimulation, an implantable pulse generator generates electrical paresthesias in the affected area through 1 or more epidural leads. The goal of this study was to evaluate the impact of tonic SCS on the sensory perception of chronic pain patients using quantitative sensory testing (QST). Materials and Methods: Forty-eight patients (mean age: 57 y) with chronic leg pain due to failed back surgery syndrome or complex regional pain syndrome treated with SCS were recruited from 3 research centers. Test procedures included 2 sessions (stimulation On or Off), with measures of detection thresholds for heat, touch, vibration, and of pain thresholds for cold, heat, pressure, the assessment of dynamic mechanical allodynia, and temporal pain summation. Three different areas were examined: the most painful area of the most painful limb covered with SCS-induced paresthesias (target area), the contralateral limb, and the ipsilateral upper limb. Wilcoxon signed-rank tests were used to compare the mean difference between On and Off for each QST parameter at each area tested. P-values <0.05 were considered significant. Results: Regarding the mean difference between On and Off, patients felt less touch sensation at the ipsilateral area (−0.4 ± 0.9 g, P=0.0125) and were less sensitive at the contralateral area for temporal pain summation (−4.9 ± 18.1 on Visual Analog Scale 0 to 100, P=0.0056) with SCS. Discussion: It is not clear that the slight changes observed were clinically significant and induced any changes in patients’ daily life. Globally, our results suggest that SCS does not have a significant effect on sensory perception