Giuliano Faccani

Glioblastoma cancer stem cells: heterogeneity, microenvironment and related therapeutic strategies

Glioblastoma Multiforme (GBM) is an incurable malignancy. GBM patients have a short life expectancy despite aggressive therapeutic approaches based on surgical resection followed by adjuvant radiotherapy and concomitant chemotherapy. Glioblastoma growth is characterized by a high motility of tumour cells, their resistance to both chemo/radio‐therapy, apoptosis inhibition leading to failure of conventional therapy. Cancer Stem Cells (CSCs), identified in GBM as well as in many other cancer types, express the membrane antigen prominin‐1 (namely CD133). These cells and normal Neural Stem Cells (NSC) share surface markers and properties, i.e. are able to self‐renew and differentiate into multiple cell types. Stem cell self‐renewal depends on microenvironmental cues, including Extracellular Matrix (ECM) composition and cell types. Therefore, the role of microenvironment needs to be evaluated to clarify its importance in tumour initiation and progression through CSCs. The specific microenvironment of CSCs was found to mimic in part the vascular niche of normal stem cells. The targeting of GMB CSCs may represent a powerful treatment approach. Lastly, in GBM patients cancer‐initiating cells contribute to the profound immune suppression that in turn correlated with CSCs STAT3 (CD133 + ). Further studies of microenvironment are needed to better understand the origin of GMB/GBM CSCs and its immunosuppressive properties. Copyright

Unraveling the contribution of ectoenzymes to myeloma life and survival in the bone marrow niche

The bone marrow provides a protected environment for generating a vast array of cell types. Bones are thus a dynamic source of structural components and soluble factors used either locally or at a distance from their site of production. We discuss the role of ectoenzymes in the bone niche where human myeloma grows. Selected ectoenzymes have been tested for their ability to promote production of substrates involved in signaling, synthesis of growth factors and hormones, and modulation of the immune response. Because of the difficulty of simultaneously tracking all these activities, we narrow our focus to events potentially influencing synthesis of adenosine (ADO), an important regulator of multiple biological functions, including local immunological tolerance. Our working hypothesis, to be discussed and partially tested herein, is that CD38, and likely BST1/CD157—both NAD+‐consuming enzymes, are active in the myeloma niche and lead a discontinuous chain of ectoenzymes whose final products are exploited by the neoplastic plasma cell as part of its local survival strategy. Coadjuvant ectoenzymes include PC‐1/CD203a, CD39, and CD73, which control the production of ADO. Results discussed here and from ongoing experiments indicate that the myeloma niche hosts the canonical, as well as alternative, pathways of ADO generation. Other possibilities are presented and discussed.

A comprehensive characterization of mitochondrial DNA mutations in glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most malignant brain cancer in adults, with a poor prognosis, whose molecular stratification still represents a challenge in pathology and clinics. On the other hand, mitochondrial DNA (mtDNA) mutations have been found in most tumors as modifiers of the bioenergetics state, albeit in GBM a characterization of the mtDNA status is lacking to date. Here, a characterization of the burden of mtDNA mutations in GBM samples was performed. First, investigation of tumor-specific vs. non tumor-specific mutations was carried out with the MToolBox bioinformatics pipeline by analyzing 45 matched tumor/blood samples, from whole genome or whole exome sequencing datasets obtained from The Cancer Genome Atlas (TCGA) consortium. Additionally, the entire mtDNA sequence was obtained in a dataset of 104 fresh-frozen GBM samples. Mitochondrial mutations with potential pathogenic interest were prioritized based on heteroplasmic fraction, nucleotide variability, and in silico prediction of pathogenicity. A preliminary biochemical analysis of the activity of mitochondrial respiratory complexes was also performed on fresh-frozen GBM samples. Although a high number of mutations was detected, we report that the large majority of them does not pass the prioritization filters. Therefore, a relatively limited burden of pathogenic mutations is indeed carried by GBM, which did not appear to determine a general impairment of the respiratory chain. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.

Neuropathic pain in post‐burn hypertrophic scars: A psychophysical and neurophysiological study

Introduction: Pain complicates hypertrophic post‐burn pathologic scars (PPS) Methods: To investigate the possible neuropathic origin of pain, 13 patients with painful PPS involving at least 1 hand underwent clinical examination, including the Douleur Neuropathique en 4 questions (DN4) questionnaire; median, ulnar, and radial nerve conduction studies (NCS); cold‐ (CDT) and heat‐induced pain threshold evaluation by quantitative sensory testing; and cutaneous silent period (CSP) testing of the abductor pollicis brevis. Controls included 9 patients with non‐painful PPS, 52 healthy subjects, and 28 patients with carpal tunnel syndrome (CTS). Results: All patients with painful PPS had possible neuropathic pain (DN4 score ≥4). NCS signs of CTS were similarly present in PPS subjects with or without pain. Hands with painful PPS had lower CDT and CSP duration, more frequent cold‐ and heat‐pain hypesthesia, and more thermal allodynia than controls. Conclusions: In PPS, possible neuropathic pain is associated with psychophysical and neurophysiological abnormalities suggestive of small‐fiber damage. Muscle Nerve 45: 883–890, 2012

Electrophysiological Predictors of Clinical Outcome in Traumatic Neuropathies: A Multicenter Prospective Study

Objectives. This prospective, observational, multicentre study aims to identify electrodiagnostic (EDX) markers of clinical recovery in patients with traumatic neuropathy (TN) receiving surgical (S) and nonsurgical (NS) treatments. Methods. Subjects referred to the Italian Traumatic Neuropathy Network between 2010 and 2011 (307 patients, for a total of 444 TN) were evaluated with serial clinical/EDX evaluations at 6, 12, 24, and 36 months of follow-up. Results. Primary surgery was performed in 21 subjects with open lesions and evidence of neurotmesis, while closed lesions were treated with either conservative medical approach (216 patients) or secondary surgery (70 patients), according to the clinical spontaneous recovery at 4-6 months. Clinical improvement correlated with the increase of the compound muscle action potential amplitude (OR 3.76; CI 1.61-8.76), particularly in the S group (OR 7.25; CI 1.2-43.87), and with sensory nerve action potential amplitude in the NS group (OR 4.35; CI 1.14-16.69). No correlations were found with needle electromyography qualitative evaluations, changes in maximal voluntary recruitment, age, and gender. Conclusions. Nerve conduction studies (NCS) represent the more accurate neurophysiological markers of clinical outcome in patients with TN. Significance. Serial NCS assessments predict the functional recovery in TN, increasing the accuracy of peripheral nerves surgical decision-making process.

89. Recovery of evoked potentials in spine surgery

The role of intraoperative neurophysiologic monitoring (IOM) in detection and prevention of an jatrogenic injury has been well documented. Only few studies, however, has been focused on recovery of evoked potentials. Aim of this study is to describe the rate of reappearance of basally unexcitable muscle-motor evoked potentials (m-MEPs) and somatosensory evoked potentials (SEPs) in a large cohort of spinal surgeries. Data on 720 spinal surgeries are shown. Transcranially elicited lower limbs m-MEPs and tibial nerve SEPs were intraoperative recorded according to standard protocols. Reasons for surgey included cervical/thoracic myelopathy (300 pts, 41.7%), spinal cord tumors (190, 26.4%), lumbar stabilization (109 pts, 15.1%), scoliosis correction (83, 11.5%), trauma (32, 4.4%) and spinal vascular malformations (6 pts, 0.8%). Overall no intraoperative changes were observed in 648 surgeries (90%), 54 (7.5%) transient or persistent deterioration of evoked potentiantials and 18 (2.5%) recovery of basally unexcitable SEPs or MEPs (9 myelopathies, 4 spinal cord tumors, 2 metastasis, 3 trauma). The large majority of these “positive” modifications (17/18, 94.4%) consisted in reappearance of MEPs. Surgical decompression of spinal cord may lead to an acute improving of spinal motoneuron functionality. IOM can provide useful information even in patient with basally absent m-MEPs.

P11.10 Impact of intraoperative D wave recording in spine surgery

implantation procedure is performed under local anaesthesia with intraoperative neurophysiological monitoring (microelectrode recording and micro or macrostimulation) for the optimal targeting and for the evaluation of stimulation-induced clinical or adverse effects. Objectives: To evaluate the feasibility of microelectrode recording for deep brain stimulation surgery in parkinsonian patients under general anaesthesia using a specific ketamine-based anaesthetic protocol and to compare the neurophysiological data obtained under these conditions with those ones obtained in the same patients previously underwent to surgery under local anaesthesia. Methods: 5 patients affected by advanced Parkinson’s disease underwent to bilateral subthalamic nucleus stimulation at first under local anaesthesia and then, owing some surgical device complications, under general anaesthesia with a total intravenous protocol based on remifentanyl and ketamine infusion. Neurophysiological data obtained under local and general anaesthesia were then analysed and compared with an off-line spike sorting software (FSPS-University of Ferrara) and a statistical analysis. Results: For all the neurophysiological parameters analysed, we didn’t find any statistical significative difference between the first and second surgical procedure. Conclusions: Subthalamic nucleus stimulation for advanced Parkinson’s disease with microelectrode recording guidance is possible and reliable under a ketamine-based general anaesthesia. So, even if awake surgery represents the “gold standard” for functional neurosurgery, general anaesthesia can be an alternative for those patients who don’t accept awake surgery because of clinical reasons, such as massive fear, reduced cooperativity, or severe “off”-medication effects.

P11.11 Intraoperative neurophysiologic assessment of traumatic spinal cord injury

Introduction: The assessment of traumatic spinal cord injury (SCI) is actually mainly made on clinical bases. Many animal models of experimental SCI showed that motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) are a sensitive measure of postinjury sensory and motor status. On the other hand, SEPs and MEPs have shown to be reliable in the assessment of the spinal cord functional integrity during spine and spinal cord surgeries. Objectives: To intraoperatively assess the spinal cord function in subjects during stabilization for spinal cord trauma, by recording muscular (mMEPs) and epidural motor evoked potentials (e-MEPs) along with cortical and epidural somatosensory evoked potentials (e-SEPs) in an effort to predict the outcome of the spinal cord injury. Methods: Intraoperative recording of m-MEPs and e-MEPs along with cortical SEPs and e-SEPs was attempted in 40 patients (19 with a complete SCI, and 12 uncompromised) during posterior stabilization for spine and spinal cord trauma. In order to test any kind of conductivity across the lesion site, in a subgroup of 6 subjects, all of them with a clinically complete SCI, the spinal cord has been stimulated cranially and caudally to the site of injury by the epidural electrodes in order to record responses from the scalp and the nerve. Results: All the uncompromised patients had normal recordings. The typical neurophysiologic pattern of complete SCI was the absence of both m-MEPs and e-MEPs caudally to the lesion site associated with a lack of cortical and e-SEPs cranially to the lesion site. In one patient with central cord syndrome the presence of D wave recorded from the caudal epidural electrode correctly predicted motor recovery. In the subgroup of 6 patients the intraoperative spinal cord stimulation positively add to the confirmation of the completeness of their lesion. Conclusion: Intraoperative neurophysiological evaluation of SCI patients can provide information about spinal cord function that is not retrievable by other clinical means and correctly predict the neurological outcome.

61. Neurophysiological prospective study in traumatic peripheral nerve injuries

This work proposes to evaluate the MEG capacity to distinguish between Alzheimer disease (AD), mild cognitive impairment (MCI) and healthy elderly subjects. 148 channel MEG system was used to record biomagnetic activity during a memory task performance in all participants (17 MCI, 20 AD, and 20 age matched controls). AD patients showed a magnetic activity sources reduction in the left temporo-parietal regions between 400 and 800 ms after the stimulus onset while the MCI patients showed a ventral pathway increased activity in comparison with the control group. The MEG would be considered as a useful clinical tool to differentiate between MCI, AD, and healthy elderly subjects.