- Blood-tissue analysis of TP53 polymorphisms and survival of patients with glioma
Bakground: The role of single nucleotide polymorphisms (SNPs) in TP53 in the pathogenesis of glioma is debated. The aim of our study was to investigate the role of several TP53 SNPs in the risk of glioma and their possible role as prognostic biomarkers of overall and progression-free survival.
Methods: We examined 12 SNPs in TP53 from peripheral blood and neoplastic tissue of patients with a diagnosis of glioma who underwent surgery from 2012 to 2015. Direct genomic sequencing of TP53 was performed to detect the presence of polymorphisms. We compared data with a matched cancer-free control group and the NCBI SNPs database. Overall and progression-free survival were analyzed in patients with glioblastoma subjected to gross total resection and concomitant radio- chemotherapy.
Results: No association was observed with glioma susceptibility and overall survival. Two new SNPs were detected: c.97-46 G>A (intron 3) and c.783-31 A>G (intron 7). The number of SNPs observed was higher (21.4%) in blood than in tumoral samples. We observed a significant reduction in progression-free survival in patients with at least one exonic SNP.
Conclusions: We can hypothesize an involvement of TP53 SNPs in response mechanisms to adjuvant treatment that may affect progression-free survival. Moreover, our blood-tissue combined study revealed a significant difference in SNPs between blood and tumoral samples, probably due to glioma heterogeneity and genomic instability.
- Practical prognostic score for predicting the extent of resection and neurological outcome of gliomas in the sensorimotor area
Objective: In this prospective study, we assessed the utility of a novel prognostic score (PS) in guiding the surgical strategy of patients with sensorimotor area gliomas.
Patients and Methods: Form December 2012 to April 2016, we collected data from patients diagnosed with brain gliomas in the sensorimotor area. All the patients had intraoperatively confirmed contiguity or continuity with sensorimotor cortical and subcortical structures. Several clinical and radiological factors were analyzed to generate a PS for each patient (range 1-8). The end-points included the extent of resection (EOR) and neurological outcome (modified Rankin Score; mRS). We assessed the predictive power of the PS using different analyses. Crosstabs analyses and Fisher’s exact test (Fet) were used to evaluate the possible predictive parameters, and for the classification of positive or negative outcomes for the chosen proxies; the significance threshold was set at p<0.05.
Results: Using independent t-tests, we compared the mRS at different time points (pre, post, and at 6 months) for 2 subgroups from the total sample using a cut-off PS value of 4. For the EOR, a PS value of ≥5 was predictive of successful outcome, a value of 4 indicated an uncertain outcome, and a value of ≤3 predicted a worse outcome.
Conclusions: This PS value can be easily used in clinical settings to help predict the functional outcome and EOR in sensorimotor area tumors. Integration with information from fMRI, DTI, and TMS, along with MRI spectroscopy could further enhance the value of this PS.
- Natural history of de novo High Grade Glioma: first description of growth parabola
Etiopathogenesis and physiopathology of gliomas are largely unknown. Recently, many authors have proved a strict correlation between the velocity of diametric expansion (VDE) on the Magnetic Resonance Imaging (MRI) and the biological behavior of these tumors, especially in Low Grade Gliomas (LGGs). Unfortunately, natural history of High Grade Gliomas (HGGs) has not been well clarified because of its fast progression, late diagnoses and early surgical intervention. We describe, for the first time to our knowledge, the case of asymptomatic patient with an incidentally discovered de novo HGG with a total of 17 months of follow-up. A male patient was referred to our consultation for routinely follow-up after meningioma resection 5 years before. He underwent MRI every year without any neuroradiological alterations. A new MRI image presented a non-enhancing lesion in the right temporal lobe with 3.55 cm of Mean Tumor Diameter (MTD) and 35.6 mm/year of VDE. After two months interval, the lesion had 3.97 cm of MTD and 27.8 mm/year of VDE. Although we have strongly suggested surgical resection, patient have delayed the operation for personal issues. After other 3 months, the tumor showed enhancement with 4.5 of MTD and 17.4 mm/year of VDE. We speculate that the descending parabola is due to initial mass effect and hypoxia of the tumor core. We also underline the crucial role of the VDE determining, in order to predict the nature of the lesion and address the most effective treatment for each patient.
- Second line treatment of recurrent glioblastoma with sunitinib: results of a phase II study and systematic review of literature
Introduction: Second line treatment of recurrent or progressive glioblastoma multiforme (GBM) is not standardized. Anti-angiogenic strategies with tyrosine-kinase inhibitors have been tested with conflicting results. We tested the association of sunitinib (S) plus irinotecan (CPT-11) in a phase II trial in terms of response rate (RR) and 6-months progression-free survival (6-PFS). We also reviewed the clinical evidence from all the trials with S in this setting published to date and summarized it in a meta-analysis.
Evidence Acquisition: Patients with GBM recurrent or progressive after surgery and standard chemo-radiotherapy were treated with S 37.5 mg/day for 14 days + CPT-11 125 mg/sqm every 14 days in a Simon’s two-stage phase II study. A summary data meta-analysis was performed to establish the 6-PFS in patients with ascertained histological diagnosis of GBM treated with sunitinib.
Evidence Synthesis: Six patients were enrolled in the stage I of the trial and only one had a stable disease. The overall response rate was 17% and 6-PFS was not reached. Therefore, the trial was stopped early for insufficient activity. All toxicities were grade 1-2. Systematic review of the literature identified 9 studies (including the present one) for a total of 221 patients. Pooled 6-PFS was 15.1% (95% CI 9.0-24.4). Subgroup analysis by different schedule revealed a 6-PFS of 17.5% (95% CI 10.3-28.1) in the weekly setting which was consistent across all the studies (I2 0%, p = 0.66) and a pooled 6-PFS of 12.7% (95% CI 4.9-29.1) in the daily setting with a substantial amount of heterogeneity (I2 65%, p = 0.01).
Conclusions: Results of this trial and those of the systematic review indicate that, compared to conventional chemotherapy or bevacizumab, S has insufficient activity in the setting of recurrent GBM. Better patient’s molecular stratification for second-line treatment in GBM is warranted.
- Minimally invasive subfrontal route for the resection of medial temporal region intrinsic tumors
Background: The mesial temporal region (MTR) comprises important components of the limbic system, as well as vital neurovascular structures. Because of its important functional role, as much healthy brain tissue as possible must be preserved while targeting resection of MTR lesions.
Methods: A frontal minicraniotomy is used to access the MTR through a subfrontal approach. By opening the most medial part of the Sylvian fissure, the uncus-amygdala complex is exposed, and through this, the head of the hippocampus can be reached and removed as well.
Conclusions: This approach is extremely suitable for MTR lesions, as it provides the advantage of sparing the most important functional structures of the temporal lobe, the temporal stem, and the limen insulae, as well as the optic radiations and the fronto-occipital connections.
- A multimodal staged approach for the resection of a Sylvian aqueduct rosette-forming glioneuronal tumor: A case report and literature review
Background and importance: The rosette-forming glioneuronal tumor (RGNT) is a rare central nervous system tumor which often arises intraventricularly. We report the first surgical case of an RGNT arising from the Sylvian aqueduct treated through a double approach.
Clinical presentation: A 25-year-old female presented with triventricular hydrocephalus on MRI secondary to a 2 cm Sylvian aqueduct mass. Emergent endoscopic third ventriculostomy with biopsy confirmed the diagnosis of RGNT. She was first followed up and due to the rapid tumor’s growth a double surgical approach was proposed. The first was a telo-velar approach to the lower third of the aqueduct. The second stage was an endoscopic ultrasound aspirator aided transfrontal transforaminal approach; last postoperative MRI shows a 6 mm residual tumor. Patient leads an active working and social life.
Conclusion: Choosing a two stages approach for this rare and complex Sylvian aqueduct RGNT resulted in a positive clinical and radiological outcome.
- The treatment of patients with 1-3 brain metastases: is there a place for whole brain radiotherapy alone, yet? A retrospective analysis
Aim: To evaluate the efficacy of whole brain radiotherapy (WBRT) with or without other treatments in patients (pts) with 1-3 brain metastases (BM).
Materials and Methods: Toxicities and survival of 134 pts treated between 2009 and 2013 with WBRT alone (58 pts), WBRT plus surgery (SUR-WBRT: 42 pts) or WBRT followed by stereotactic or integrated boost radiotherapy (SRT-WBRT: 34 pts) were analyzed. Differences in toxicity (acute and late) incidence and in overall (OS), disease-free (DFS) and disease-specific survival (DSS) were evaluated (χ(2)-test, uni- and multivariate analysis).
Results: Pts given intensified treatments (SUR- and SBRT-WBRT) had better 3-month local response compared to WBRT alone group (p < 0.045). Better 1-year local control was evident only in SRT-WBRT pts (p < 0.035). Univariate OS analysis confirmed, as favorable prognostic factors, RPA class I (p < 0.001), GPA class III and IV (p < 0.001), single metastasis (p = 0.045), stable primary disease (p = 0.03), intensified treatment (p = 0.000), systemic therapy after radiotherapy (p = 0.04) and response of metastatic lesions (p = 0.002). At multivariate analysis, OS was better in RPA class I pts (p = 0.002), who had more aggressive radiotherapy treatments (p = 0.001), chemotherapy after radiotherapy (p < 0.001) and response to RT (p = 0.003). Response to radiotherapy (p = 0.002) and BM number (p < 0.001) resulted independently prognostic for DFS. About 60 % of patients had mild acute toxicity (G1), especially headache (51 %) and fatigue (34 %); only 2 patients (2 %) had severe (G3) headache and 5 patients (4 %) severe fatigue (G3) reversible with oral steroids. No differences were evident between the different treatment groups. Among 80 pts followed up with MRI, 12 (15 %) had leukoencephalopathy (equally distributed across subgroups) and 5 (6 %) radionecroses, 4/5 asymptomatic, 5/5 in pts given intensified treatments.
Conclusions: This analysis confirms the known prognostic factors for BM, emphasizing the importance of intensified treatments in a population with favorable features.
- Resection of supratentorial gliomas: the need to merge microsurgical technical cornerstones with modern functional mapping concepts. An overview.
Although surgery is not curative for the majority of intracranial gliomas, radical resection has been demonstrated to influence survival and delay tumor progression. Because gliomas are very frequently located in eloquent or more generally critical areas, surgeons must always balance the maximizing resection with the need to preserve neurological function. In this overview, we tried to summarize the recent literature and our personal experience about (1) the benefits and limits of using preoperative anatomical and functional neuroimaging (anatomical MRI, DTI fiber tracking, and functional MRI), (2) the issues to consider in planning the surgical strategy, (3) the need to thoroughly understand microsurgical techniques that enable a maximal resection (subpial dissection, vascular manipulation, etc.), (4) the importance of individualizing surgical strategy especially in patients with gliomas in eloquent areas (the role of neuropsychological evaluation in redefining eloquent and non-eloquent areas), and (5) how to use intraoperative mapping techniques and understand why and when to use them. Through this paper, the reader should become more familiar with a comprehensive panel of techniques and methodologies but more importantly become aware that these recent technical advances facilitate a conceptual change from classical surgical paradigms toward a more patient-specific approach.
- Three-dimensional conformal radiotherapy, static intensity-modulated and helical intensity-modulated radiotherapy in glioblastoma. Dosimetric comparison in patients with overlap between target volumes and organs at risk
Aims and Background: Radiotherapy is the standard treatment of glioblastoma. Three-dimensional conformal radiotherapy is the standard technique to treat glioblastoma. Intensity-modulated radiotherapy and helical intensity-modulated radiotherapy (tomotherapy) are becoming widely used. The present study compared three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy in terms of target coverage and preservation of organs at risk.
Methods: Ten patients treated with three-dimensional conformal radiotherapy, with a target volume close to or superimposed to the organs at risk, were retrospectively selected. The plans were re-planned with step-and-shoot 3/5 fields intensity-modulated radiotherapy and tomotherapy. Target coverage and sparing of organs at risk were statistically compared.
Results: Mean planning target volume V95% improved with sophisticated techniques (87.2%, 93.2%, 97.6% with three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy, respectively). The comparison of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy did not show significant differences, whereas differences were significant when three-dimensional conformal radiotherapy and tomotherapy as well as intensity-modulated radiotherapy and tomotherapy were compared. Mean planning target volume/clinical target volume D99-D98-D95 were not different between three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, but they were different between tomotherapy and three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, with better clinical target volume/and planning target volume coverage with the tomotherapy plans. Brain D33/66 were 31.1/11.8 Gy, 37.5/18.3 Gy and 28.5/14.7 Gy with three-dimensional conformal radiotherapy, intensity-modulated radiotherapy and tomotherapy, respectively. Mean brainstem, optic nerves and chiasma Dmax were always within the defined constraints. The homogeneity index improved with intensity-modulated radiotherapy/tomotherapy compared to three-dimensional conformal radiotherapy. Tomotherapy was better than intensity-modulated radiotherapy in all patients.
Conclusions: In this selected group of patients, a significant dosimetric advantage was evident for tomotherapy compared with three-dimensional conformal radiotherapy and intensity-modulated radiotherapy. Significant advantages were evident in terms of panning target volume coverage (V95), D99, D98 and D95. The clinical significance of the results should be defined.
- Acute functional reactivation of the language network during awake intraoperative brain mapping
Acute brain plasticity during resection of central lesions has been recently described. In the cases reported, perilesional latent networks, useful to preserve the neurological functions, were detected in asymptomatic patients. In this paper, we presented a case of acute functional reactivation (AFR) of the language network in a symptomatic patient. Tumor resection allowed to acutely restore the neurological deficit. Intraoperative direct cortical stimulation (DCS) and functional neuroimaging showed new epicentres of activation of the language network after tumor excision. DCS in awake surgery is mandatory to reveal AFR needful to improve the extent of resection preserving the quality of life.
- Surgery in cerebral metastases: are numbers so important?
Background: The prognosis of cerebral metastases (MTS) is linked to progression of both systemic and local disease. The importance of MTS resection has been already pointed out. The observation of a high mortality for not-neurological causes confirms that the modern treatments allow a significant control of the disease within the nervous system. Nevertheless, management difficulties increase with multiple lesions and in these cases the role of surgery has still to be defined.
Materials and Methods: We collected the clinical data of patients operated in two centers for cerebral MTS from lung carcinoma during 8 years. Patient selection for surgery followed definite criteria; the limit for multiple MTS was three. We analyzed the functional and survival outcomes of the cohort.
Results and Conclusions: Our series included 242 patients: 105 had multiple MTS. Statistical analysis did not show significant differences in mean survival and outcomes between patients with single and multiple lesions. The decease occurred for neurological causes in 15.7% of cases. The selection of candidates for surgery requires several considerations and entails the success rate of this treatment. In patients with the multiple lesions who fulfilled the selection criteria we observed a nevertheless satisfying success after the operation. Our results imply that surgery may be applied also in selected patients with more diffuse intracranial disease. A pre-operative accurate patient selection is related to acceptable quality-of-life following the operation even in cases of multiple MTS.
- Supratentorial gliomas in eloquent areas: which parameters can predict functional outcome and extent of resection?
Background: To date, few parameters have been found that can aid in patient selection and surgical strategy for eloquent area gliomas.
Aims: The aim of the study was to analyze preoperative and intraoperative factors that can predict functional outcome and extent of resection in eloquent area tumors.
Patients and Methods: A retrospective analysis was conducted on 60 patients harboring supratentorial gliomas in eloquent areas undergoing awake surgery. The analysis considered clinical, neuroradiologic (morphologic), intraoperative, and postoperative factors. End-points were extent of resection (EOR) as well as functional short- and long-term outcome. Postoperatively, MRI objectively established the EOR. χ(2) analyses were used to evaluate parameters that could be predictive. Multivariate logistic regression analyses were used to evaluate the best combination to predict binary positive outcomes.
Results: In 90% of the cases, subcortical stimulation was positive in the margins of the surgical cavity. Postoperatively, 51% of the patients deteriorated but 90% of the patients regained their preoperative neurological score. Factors negatively affecting EOR were volume, degree of subcortical infiltration, and presence of paresis (P<0.01). Sharp margins and cystic components were more amenable to gross total resection (P<0.01). Contrast enhancement (P<0.02), higher grade (P<0.01), paresis (P<0.01), and residual tumor in the cortex (P<0.02) negatively affected long-term functional outcomes, whereas postoperative deterioration could not be predicted for any factor other than paresis. Subcortical stimulation did not correlate with deterioration, both postoperatively (P<0.08) and at follow-up (P<0.042).
Conclusions: Biological and morphological factors such as type of margins, volume, preoperative neurological status, cystic components, histology and the type of infiltration into the white matter must be considered when planning intraoperative mapping.
- A retrospective two-center study of antiepileptic prophylaxis in patients with surgically treated high-grade gliomas
Background: The effectiveness of antiepileptic prophylaxis in patients with newly diagnosed high-grade glioma is debated. Craniotomy, surgical manipulation and bleeding are believed to favor the onset of seizures and, therefore, perioperative antiepileptic drugs (AEDs) are generally used. Nevertheless, evidence to initiate preoperative AED prophylaxis are weak.
Aim: Aim of this paper was to evaluate the need for AED prophylaxis in surgically-treated malignant glioma patients without history of seizures.
Materials and Methods: We conducted a retrospective, two-center cohort study to assess the effectiveness of preoperative AED prophylaxis. Patients were divided in two groups: one with AED preoperative administration and the other without. Because of its non-hepatic metabolism, levetiracetam (LEV) was chosen. Logistic regression models were used to investigate the odds ratio for each group. The explanatory variables included the treatment received, sex, age, and site of lesion. The outcome measure of successful LEV prophylaxis was seizure vs. no seizure post-operatively, at three and six months after surgery.
Results: Our results showed that LEV prophylaxis was not a significant predictor of seizure occurrence, although the regression coefficient indicated a slight reduction in seizure risk following LEV administration. Patient’s age was a significant predictor of seizure occurrence. Younger patients had a higher risk of seizure in the six months post-surgery.
Conclusions: We conclude that AEDs prophylaxis does not provide a substantial benefit to surgically treated high-grade glioma patients and should not be administered routinely. Further investigations are required to detect subgroups of patients at higher risk of developing seizures in order to selectively administer AED.
- Purely subcortical tumors in eloquent areas: awake surgery and cortical and subcortical electrical stimulation (CSES) ensure safe and effective surgery
Objective: To analyze the efficacy and safety of cortical and subcortical electrical stimulation CSES and awake surgery to approach purely subcortical tumors in highly functional locations, particularly in guiding the choice of the best transcortical path.
Patients and Methods: Prospective analysis of the surgical, neurological, and radiological outcome of patients harboring supratentorial, subcortically located brain tumors or vascular malformations who are operated on through awake surgery and CSES. Functional magnetic resonance (fMRI; either sensory-motor or language, based on the location) was performed in order to confirm the proximity to functional cortical areas. Major white matter tracts were investigated by MRI diffusion tensor fiber tracking (DTI-ft). The Rankin modified score was chosen to express the pre and postoperative functional neurological status. Immediate postoperative MRI was used to evaluate the extent of resection.
Results: Seventeen patients were selected. The main distance of the tumors from the cortical surface was 18.2mm (range 9-48 mm). Neuronavigation was used to show the most direct route to the tumor (transsulcal or transgyral), but CSES was fundamental to adapt the surgical corridor to the functional topography both cortically and subcortically. If the transgyral route was chosen, CSES helped to detect a non-eloquent area. When a transsulcal route was preferred, CSES documented the presence or absence of function in the deep sulcus. The transient postoperative morbidity was 76.4%, but at last follow-up (range 4-20 months), all the patients regained preoperative status and 2 improved. Postoperative MRI demonstrated complete resection in all cases.
Conclusions: Approaching purely subcortical tumors requires microsurgical skills, but in eloquent areas, functional topography monitoring is mandatory to allow safe surgery. CSES in an awake patient is a method that produces very good results in terms of resection and neurological outcome.
- 5-aminolevulinic acid and neuronavigation in high-grade glioma surgery: results of a combined approach
In high-grade glioma surgery, several techniques are used to achieve the maximum cytoreductive treatment preserving neurological functions. However, the effectiveness of all the methods used alone is reduced by specific limitations of each. We assessed the reliability of a multimodal strategy based on 5-aminolevulinic acid (5-ALA) and neuronavigation. We prospectively studied 18 patients with suspected, non eloquent-area malignant gliomas amenable for complete resection. Conventional illumination was used until the excision appeared complete. The cavity was then systematically inspected in violet-blue light to identify any residual tumour. Multiple biopsies of both fluorescent and non-fluorescent tissue were performed in all cases. Each specimen was labelled according to the sampling location (inside or outside the boundary set by the neuronavigator). The samples were analysed by a neuropathologist blinded to the intraoperative classification. We reviewed the results of both methods, either singly or in combination. Individual analysis showed higher 5-ALA reliability compared to neuronavigation. However, several false-negative fluorescent specimens were detected. With the combined use of fluorescence and neuroimaging, only 1 sample (negative for both 5-ALA and navigation) was tumoral tissue. In our experience, the combined approach showed the best sensitivity and it is recommended in cases of lesions involving non-eloquent areas.
- Fluorescence and image guided resection in high grade glioma
The extent of resection in high grade glioma is increasingly been shown to positively effect survival. Nevertheless, heterogeneity and migratory behavior of glioma cells make gross total resection very challenging. Several techniques were used in order to improve the detection of residual tumor. Aim of this study was to analyze advantages and limitations of fluorescence and image guided resection. A multicentric prospective study was designed to evaluate the accuracy of each method. Furthermore, the role of 5-aminolevulinc acid and neuronavigation were reviewed. Twenty-three patients harboring suspected high grade glioma, amenable to complete resection, were enrolled. Fluorescence and image guides were used to perform surgery. Multiple samples were obtained from the resection cavity of each lesion according to 5-ALA staining positivity and boundaries as delineated by neuronavigation. All samples were analyzed by a pathologist blinded to the intra-operative labeling. Decision-making based on fluorescence showed a sensitivity of 91.1% and a specificity of 89.4% (p<0.001). On the other hand, the image-guided resection accuracy was low (sensitivity: 57.8%; specificity: 57.4%; p=0.346). We observed that the sensitivity of 5-ALA can be improved by the combined use of neuronavigation, but this leads to a significant reduction in specificity. Thus, the use of auxiliary techniques should always be subject to critical skills of the surgeon. We advocate a large-scale study to further improve the assessment of multimodal approaches.
Ricerca Neuro-Oncologica Sperimentale
- Solid lipid nanoparticles by coacervation loaded with a methotrexate prodrug: preliminary study for glioma treatment
Aim: Methotrexate-loaded biocompatible nanoparticles were tested for preliminary efficacy in glioma treatment.
Materials & Methods: Behenic acid nanoparticles, prepared by the coacervation method, were loaded with the ester prodrug didodecylmethotrexate, which was previously tested in vitro against glioblastoma human primary cultures. Nanoparticle conjugation with an ApoE mimicking chimera peptide was performed to obtain active targeting to the brain.
Results & Conclusion: Biodistribution studies in healthy rats assessed the superiority of ApoE-conjugated formulation, which was tested on an F98/Fischer glioma model. Differences were observed in tumor growth rate (measured by MRI) between control and treated rats. In vitro tests on F98 cultured cells assessed their susceptibility to treatment, with consequent apoptosis, and allowed us to explain the apoptosis observed in glioma models.
- Comparison of Allogeneic and Syngeneic Rat Glioma Models by Using MRI and Histopathologic Evaluation
Research in neurooncology traditionally requires appropriate in vivo animal models, on which therapeutic strategies are tested before human trials are designed and proceed. Several reproducible animal experimental models, in which human physiologic conditions can be mimicked, are available for studying glioblastoma multiforme. In an ideal rat model, the tumor is of glial origin, grows in predictable and reproducible patterns, closely resembles human gliomas histopathologically, and is weakly or nonimmunogenic. In the current study, we used MRI and histopathologic evaluation to compare the most widely used allogeneic rat glioma model, C6-Wistar, with the F98-Fischer syngeneic rat glioma model in terms of percentage tumor growth or regression and growth rate. In vivo MRI demonstrated considerable variation in tumor volume and frequency between the 2 rat models despite the same stereotactic implantation technique. Faster and more reproducible glioma growth occurred in the immunoresponsive environment of the F98-Fischer model, because the immune response is minimized toward syngeneic cells. The marked inability of the C6-Wistar allogeneic system to generate a reproducible model and the episodes of spontaneous tumor regression with this system may have been due to the increased humoral and cellular immune responses after tumor implantation.
- Solid Lipid Nanoparticles Loaded with Antitumor Lipophilic Prodrugs Aimed to Glioblastoma Treatment: Preliminary Studies on Cultured Cells
The treatment of glioblastoma multiforme (GBM), the most malignant human glioma, is hampered mainly by the polyclonality and by the invasion modalities of the tumor, by the cell resistance to therapy and by the blood-brain barrier (BBB) presence. Solid lipid nanoparticles (SLN) have been recently proposed as vehicles for anticancer drugs for GBM treatment, according to their ability to enhance drug uptake by BBB endothelial cells and to evade cell resistance mechanisms. Moreover, their surface can be engineered in order to be selectively directed towards BBB. Nevertheless, many anticancer drugs are too hydrophilic to be loaded in the lipid matrix. In this experimental work an innovative formulation technology, named coacervation, was employed for SLN preparation, while anticancer drug loading was obtained through a lipophilic prodrug synthetic approach. Preliminary aims were the assessment of the cytotoxicity of the obtained formulations against GBM cultures obtained from human primary tumors, and of their potentiality in BBB overcoming by using cellular models. The encouraging results obtained with various anticancer drugs will pulse further studies in animal models in order to investigate their in vivo fate.
- Role of Nitric Oxide in Glioblastoma Therapy: Another Step to Resolve the Terrible Puzzle?
Glioblastoma Multiforme, the most common and aggressive primary brain tumor, remains incurable despite of the advent of modern surgical and medical treatments. This poor prognosis depends by the recurrence after surgery and intrinsic or acquired resistance to chemotherapy and radiotherapy. Nitric oxide is a small molecule that plays a key roles in glioma pathophysiology. Many researches showing that NO is involved in induction of apoptosis, radiosensitization and chemosensitization. Therefore, NO role, if clarified, may improve the knowledge about this unsolved puzzle called GBM.
- Positive-charged solid lipid nanoparticles as paclitaxel drug delivery system in glioblastoma treatment
Paclitaxel loaded solid lipid nanoparticles (SLN) of behenic acid were prepared with the coacervation technique. Generally, spherical shaped SLN with mean diameters in the range 300–600 nm were obtained. The introduction of charged molecules, such as stearylamine and glycol chitosan into the formulation allowed to obtain positive SLN with Zeta potential in the 8-20 mV range and encapsulation efficiency in the 25–90% range.Blood–brain barrier (BBB) permeability, tested in vitro through hCMEC/D3 cells monolayer, showed a significantly increase in the permeation of Coumarin-6, used as model drug, when vehicled in SLN. Positive-charged SLN do not seem to enhance permeation although stearylamine-positive SLN resulted the best permeable formulation after 24 h.Cytotoxicity studies on NO3 glioblastoma cell line demonstrated the maintenance of cytotoxic activity of all paclitaxel-loaded SLN that was always unmodified or greater compared with free drug. No difference in cytotoxicity was noted between neutral and charged SLN.Co-culture experiments with hCMEC/D3 and different glioblastoma cells evidenced that, when delivered in SLN, paclitaxel increased its cytotoxicity towards glioblastoma cells.
- Solid lipid nanoparticles for potential doxorubicin delivery in glioblastoma treatment: preliminary in vitro studies
The major obstacle to glioblastoma pharmacological therapy is the overcoming of the blood-brain barrier (BBB). In literature, several strategies have been proposed to overcome the BBB: in this experimental work, solid lipid nanoparticles (SLN), prepared according to fatty acid coacervation technique, are proposed as the vehicle for doxorubicin (Dox), to enhance its permeation through an artificial model of BBB. The in vitro cytotoxicity of Dox-loaded SLN has been measured on three different commercial and patient-derived glioma cell lines. Dox was entrapped within SLN thanks to hydrophobic ion pairing with negatively charged surfactants, used as counterions. Results indicate that Dox entrapped in SLN maintains its cytotoxic activity toward glioma cell lines; moreover, its permeation through hCMEC/D3 cell monolayer, assumed as a model of the BBB, was increased when the drug was entrapped in SLN. In conclusion, SLN proved to be a promising vehicle for the delivery of Dox to the brain in glioblastoma treatment.
- Stem cells based therapy in high grade glioma: why the intraventricular route should be preferred?
Aim: Mesenchymal stem cells (MSCs) migrate in response to chemokines and possess extensive tropism for experimental glioma. Antitumor effects have been reported following intracranial and intravenous administration of gene-modified MSCs. Among the different routes for cell transplant, the intraventricular (IV) approach found very little employment in comparison with intraparenchymal, intratumoral and intravenous administration protocols. Nevertheless, IV transplantation offers advantages in terms of cells viability and distribution toward target sites, opening interesting opportunities for its clinical application.
Methods: Using a rat glioma model, we investigated migratory capacity, tumor tropism, distribution and differentiation of MSCs following IV administration.
Results: Transplanted MSCs create niches of viable cells in the subventricular zone and can be stimulated to migrate to sites of tumor infiltration. MSCs seemed not to be involved in tumor growth and angiogenesis.
Conclusion: We speculate that the IV route can be used to achieve a kind of reservoir of self-renewal cells, potentially active against the spread of cancer cells. Further studies are needed to shed light on MSCs distribution close to the ventricular wall, in order to define their lifespan and their capacity to migrate towards new-enhancing foci time after implantation.