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Biomedical subjects

Giulio Maira

Publications and source records attributed to Giulio Maira.

At least 19 recordsLinked to original sources
PubMed2006

Telomerase inhibition by stable RNA interference impairs tumor growth and angiogenesis in glioblastoma xenografts.

Telomerase is highly expressed in advanced stages of most cancers where it allows the clonal expansion of transformed cells by counteracting telomere erosion. Telomerase may also contribute to tumor progression through still undefined cell growth-promoting functions. Here, we inhibited telomerase activity in 2 human glioblastoma (GBM) cell lines, TB10 and U87MG, by targeting the catalytic subunit, hTERT, via stable RNA interference (RNAi). Although the reduction in telomerase activity had no effect on GBM cell growth in vitro, the development of tumors in subcutaneously and intracranially grafted nude mice was significantly inhibited by antitelomerase RNAi. The in vivo effect was observed within a relatively small number of population doublings, suggesting that telomerase inhibition may hinder cancer cell growth in vivo prior to a substantial shortening of telomere length. Tumor xenografts that arose from telomerase-inhibited GBM cells also showed a less-malignant phenotype due both to the absence of massive necrosis and to reduced angiogenesis.

Animals↗
PubMed2006

A plasmid-encoded VEGF siRNA reduces glioblastoma angiogenesis and its combination with interleukin-4 blocks tumor growth in a xenograft mouse model.

Angiogenesis is required for the development and biologic progression of glioblastoma multiform (GBM), which is the most malignant infiltrative astrocytoma. Vascular endothelial growth factor (VEGF) plays a predominant role in the increased vascularity and endothelial cell proliferation in GBMs driven by the expression of pro-angiogenic cytokines. In this study, we employed a vector-encoded VEGF siRNA to impair VEGF secretion from U87 human glioblastoma cells. The direct intra-tumor injection of a siRNA-encoding plasmid complexed with linear polyethylenimine (PEI) efficiently reduced the vascularization of treated tumors in xenografts established in SCID mice by subcutaneous inoculation of U87 cells, but was not able to reduce tumor growth. We then sought to strengthen the in vivo action of our siRNA by coupling it to a well known direct antiangiogenic agent, mouse interleukin 4 (mIL4). We infected U87 cells with a retroviral vector coexpressing the VEGF siRNA and mIL4 and produced stable cell lines that we used for an in vivo experiment of subcutaneous injection in SCID mice. In this setting, the concomitant expression of mIL4 and siRNA totally abolished the growth of subcutaneous tumors. These results suggest that our retroviral vector might be employed as a potential tool in future antiangiogenic gene therapy trials for glioblastoma.

Animals↗
PubMed2006

Influence of local environment on the differentiation of neural stem cells engrafted onto the injured spinal cord.

OBJECTIVES: In vitro, neural stem cells (NSCs) proliferate as undifferentiated spheroids and differentiate into neurons, astrocytes and oligodendrocytes. These features make NSCs suitable for spinal cord (SC) reconstruction. However, in vivo experiments have demonstrated that in the injured SC transplanted NSCs either remain undifferentiated or differentiate into the astrocytic phenotype. The microenvironment of the injured SC is believed to play a crucial role in driving the differentiation of the engrafted NSCs. Here, we tested the hypothesis that inflammatory cytokines (ICs) may be involved in the restricted differentiation of NSCs after grafting onto the injured SC. METHODS: As the first step, we used immunohistochemistry to analyse the expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and interferon (IFN)-gamma in the normal SC of mice and following traumatic injury. Then, we investigated whether a combination of TNF-alpha, IL-1beta and IFN-gamma may affect the phenotype of murine NSCs in vitro. RESULTS: We found that TNF-alpha, IL-1beta and IFN-gamma, which are absent in the normal SC, are all expressed in the injured SC and the expression of these cytokines follows a timely tuned fashion with IFN-gamma being detectable as long as 4 weeks after injury. In culture, exposure of proliferating NSCs to a combination of TNF-alpha, IL-1beta and IFN-gamma was per se sufficient to induce the astrocytic differentiation of these cells even in the absence of serum. CONCLUSIONS: In the traumatically injured SC, differentiation of engrafted NSCs is restricted towards the astrocytic lineage because of the inflammatory environment. ICs are likely to play a major role in differentiation of NSCs in the in vivo conditions.

Animals↗
PubMed2006

In vitro analysis of mouse neural stem cells genetically modified to stably express human NGF by a novel multigenic viral expression system.

OBJECTIVES: The purpose of this study was to characterize mouse neural stem cells (NSC) transduced by a multigenic lentiviral vector (LV) and stably express recombinant human nerve growth factor (rhNGF). We obtained NSC-derived cell lines which express human NGF in relevant amount to exploit their ability for therapeutic applications. METHODS: We constructed advanced multigenic LV vectors which contain a tricistronic cassette to express simultaneously up to three independent genes: (1) rhNGF (beta subunit); (2) EGFP (enhanced green fluorescent protein) and (3) Neo(R) (neomycin antibiotic resistance gene). Lentiviruses were obtained by transfecting LV constructs plus helper plasmids in human embryonic kidney (HEK)-293T packaging cells. Lentiviral virions were released in culture media and subsequent used to infect mouse NSC. Genetycin 418-resistant NSC were obtained after 1 month of selection in the presence of antibiotic (G418). Levels of human NGF secreted by rhNGF-NSC were determined by ELISA (enzyme-linked immunosorbent assay). Features of multipotentiality of engineered NSC-derived cell lines versus naive cells (control-NSC) were assessed by immunocytochemical analysis in differentiation conditions. Self-renewal of NSC was tested by neurospheres assay (NSA). RESULTS: Levels of secreted human NGF, from conditioned media obtained by rhNGF-NSC cultures, were found to be elevated in either proliferation or differentiation conditions as compared with control cells. Moreover, released hNGF demonstrated biologic activity on PC12 cells by a functional test of neurite outgrowth. Immunocytochemical analysis revealed that engineered NSC showed to be all positives for EGFP. After thirty passages in vitro in the presence of G418, engineered cells versus naive NSC cultures maintained their multipotentiality to differentiate into neurons, astrocytes and oligodendrocytes. Furthermore, it was found that rhNGF-NSC-derived neurons expressed choline acetyltransferase (ChAT) and displayed an enhanced axonal growth. NSA showed an altered sphere forming frequency either in rhNGF-NSC or both group of control NSC. DISCUSSION: Lentivirus-mediated rhNGF gene transfer into NSC was achieved using a new version of LV vectors. We obtained rhNGF-NSC-derived cell lines which released hNGF to high levels in the culture medium. The expression of neural differentiation markers, like microtubule associated protein 2 (MAP2) (a/b), glial fibrillary acidic protein (GFAP) and chondroitin sulphate proteoglycan (NG2), was not enhanced in rhNGF-NSC compared with control cells. Secreted hNGF increased axonal sprouting by rhNGF-NSC-derived neurons which was associated with ChAT expression. rhNGF-NSC may prospectively be good candidates for the treatment of either neurodegenerative diseases such as Alzheimer disease or central nervous system injuries.

Animals↗
PubMed2006

Telomerase inhibition impairs tumor growth in glioblastoma xenografts.

Telomerase is a specialized DNA polymerase that is required to replicate the ends of linear chromosomes, the telomeres. The majority of human cancers express high levels of telomerase activity that is permissive for tumor growth because it provides cells with an extended proliferative potential. Additionally, telomerase exerts cell growth promoting functions and favors cell survival. Human glioblastoma multiforme (GBM) cells express high level of telomerase activity owing to the overexpression of human telomerase reverse transcriptase (hTERT), the limiting subunit of the enzyme. Here we used retroviral mediated RNA interference to dampen down telomerase activity in two distinct human GBM cell lines, U87MG and TB10. Substantial decrease of hTERT mRNA and telomerase activity had only minimal effects on telomere length maintenance, cell growth and survival in vitro. On the contrary, development of tumors upon subcutaneously grafting of U87MG and TB10 cells and intracranial implantation of U87MG cells in nude athymic mice was strongly reduced by telomerase inhibition.

Animals↗
PubMed2006

Idiopathic spinal cord herniation: diagnostic, surgical, and follow-up data obtained in five cases.

Idiopathic spinal cord herniation (ISCH) is a rare, although increasingly recognized, cause of myelopathy. It is the result of an anterior dural defect in the thoracic spine through which the spinal cord herniates. Surgical restoration of the herniated cord to its normal position is usually followed by significant improvement in patients' clinical status. Differing surgical techniques have been used to manage the dural defect. In this report the authors discuss the cases of five patients (four women and one man) with ISCH treated during a 13-year period. Clinical and imaging findings in each patient are reported. Two different surgical techniques were used to treat this condition: dural defect enlargement in two cases and dural patch secured with stitches in three. The intra- and postoperative findings are discussed in relation to the two surgical techniques. Based on the results and complications in these five cases, the authors now believe that ISCH should be treated, when feasible, by using a dural patch to close the dural defect at the site of the herniation.

Adult↗
PubMed2005

Primary empty sella.

CONTEXT: The term primary empty sella (PES) refers to a number of endocrine and/or neurological disturbances that may be caused by the herniation of subarachnoid space within the sella. SETTING: The records of all patients with a diagnosis of empty sella between 1985 and 2002 seen at the Catholic University of Rome and University of Brescia were examined retrospectively. PATIENTS: We have observed 171 female and 42 male patients affected by PES (over 4:1 sex ratio). The mean age at diagnosis in our subjects was 51.8 +/- 2.1 yr. Mean body mass index was 27.3 +/- 3.5 kg/m2. MAIN OUTCOME MEASURE: All the patients have been analyzed first either with sellar computed tomography scan or magnetic resonance imaging. All patients underwent neurological, ophthalmological, and baseline endocrine evaluation (appropriate stimulation tests were performed when hypopituitarism was suspected). RESULTS: In the overall population, 40 of 213 patients had documented endocrine abnormalities, specifically 31 females and nine males. Twenty-two patients (10.3% of total patients; 18 women, 10.5% of all women, with a mean age of 38.6 +/- 1.1 yr and four males, with a mean age 46.5 +/- 3.52 yr) presented with hyperprolactinemia. Global anterior hypopituitarism was confirmed in nine patients. Eight patients presented an isolated GH deficiency. One hundred thirty-eight of our patients presented a so-called partial empty sella at computed tomography scan/magnetic resonance imaging, and 75 had total PES. CONCLUSIONS: PES may be associated with variable clinical conditions ranging from mild endocrine disturbances to severe intracranial hypertension and rhinorrhea. The need for treatment of hyperprolactinemia as well as for replacement hormone therapy must be assessed in PES. Symptomatic intracranial hypertension makes cerebrospinal fluid shunting procedures necessary.

Adult↗
PubMed2005

Long survival in an untreated solitary choroid plexus metastasis from renal cell carcinoma: case report and review of the literature.

Brain metastases from renal cell carcinoma (RCC) are rare. Among them, the metastases localized only in the choroid plexus are exceptional and only six cases are reported in the literature. Here we report on a patient with a single choroid plexus metastasis from RCC which presented an unusual biological behaviour. For several years, such metastasis was interpreted as a benign intraventricular tumor and was not treated. Four years after the initial neuroradiological evidence, because of the appearance of symptoms, the brain metastasis was excised. We think that this unusual biological behaviour of the tumor determined the late inset of the neurological symptoms, despite the location at the choroid plexus that usually leads to an early obstructive hydrocephalus. To our knowledge, this 46 months survival is the longest survival of a patient affected by a single choroid plexus metastasis from RCC.

Aged↗
PubMed2005

Homologous transplantation of neural stem cells to the injured spinal cord of mice.

OBJECTIVE: Murine neural stem cells (NSCs) were homografted onto the injured spinal cord (SC) to assess their potential to improve motor behavior, to differentiate as neurons, and to establish synapse-like contacts with the descending axonal paths of the host. In addition, we investigated whether transduced NSCs over-expressing vascular endothelial growth factor might exert any angiogenetic effect in the injured SC. METHODS: NSCs derived from mouse embryos were transduced to express either green fluorescent protein or vascular endothelial growth factor. The cells were engrafted in mice where an extended dorsal funiculotomy had been performed at the T8-T9 level. At intervals from 4 to 12 weeks after grafting, motor behavior was assessed using an open field locomotor scale and footprint analysis. At the same time points, the SC was studied by conventional histology, immunohistochemistry, and fluorescence microscopy. The interactions between the grafted NSCs and descending axonal paths were investigated using anterogradely transported fluorescent axonal tracers. RESULTS: By the 12-week time point, mice engrafted with NSCs significantly improved both their locomotor score on open field test and their base of support on footprint analysis. Histological studies showed that green fluorescent protein-positive NSCs survived as long as 12 weeks after grafting, migrated from the grafting site with a tropism toward the lesion, and either remained undifferentiated or differentiated into the astrocytic phenotype without neuronal or oligodendrocytic differentiation. Interestingly, the NSC-derived astrocytes expressed vimentin, suggesting that these cells differentiated as immature astrocytes. The tips of severed descending axonal paths came adjacent to grafted NSCs without forming synapse-like structures. When genetically engineered to over-express vascular endothelial growth factor, the grafted NSCs significantly increased vessel density in the injured area. CONCLUSION: In the traumatically injured mice SC, NSC grafting improves motor recovery. Although differentiation of engrafted NSCs is restricted exclusively toward the astrocytic phenotype, the NSC-derived astrocytes show features that are typical of the early phase after SC injury when the glial scar is still permissive to regenerating axons. The immature phenotype of the NSC-derived astrocytes suggests that these cells might support neurite outgrowth by the host neurons. Thus, modifying the glial scar with NSCs might enhance axonal regeneration in the injured area. The use of genetically engineered NSCs that express trophic factors appears to be an attractive tool in SC transplantation research.

Animals↗
PubMed2005

Pyrogenic cytokine interleukin-6 expression by a chordoid meningioma in an adult with a systemic inflammatory syndrome. Case report and review of the literature.

Chordoid meningioma is a rare meningothelial tumor characterized by chordoma-like histological features with lymphoplasmacellular infiltration. This tumor is often seen in children, but not in adults, with a systemic inflammatory syndrome (iron-resistant microcytic anemia and/or dysgammaglobulinemia) and very rarely with a persistent moderate hyperthermia. In the present report the authors describe a temporal chordoid meningioma in a 30-year-old woman who presented with fever, headache, and a serological inflammatory syndrome. The clinical symptomatology, chiefly the fever, disappeared immediately after removal of the tumor. To the authors' knowledge, only one similar patient with such clinical presentation and response to surgery has been mentioned in the literature. Interestingly, at immunohistochemical examination, the neoplasm showed focal positivity for the pyrogenic cytokine interleukin-6. The capacity of the tumor to produce this pyrogenic cytokine could explain both the patient's clinical presentation and her response to the surgical management.

Adult↗
PubMed2005

Primary empty sella syndrome in a series of 142 patients.

OBJECT: The primary empty sella syndrome (ESS) represents a heterogeneous clinical picture characterized by endocrine disturbances and signs of intracranial hypertension. An increase in intracranial pressure (ICP) is proposed to be one of the involved pathogenetic factors. METHODS: The series included 142 patients who were observed during a period of 20 years. All patients underwent an ICP and cerebrospinal fluid (CSF) dynamics evaluation through the use of a lumbar constant-rate infusion test. Impairment of ICP and CSF dynamics was observed in 109 patients (76.8%). In 35 of the 36 patients affected by severe intracranial hypertension without rhinorrhea, improvement in adverse neurological symptoms was achieved after implanting a CSF shunt. Visual function, already seriously compromised before surgery, remained severely altered in one patient. In the group of 34 patients affected by rhinorrhea, CSF leakage was controlled using different surgical treatments: CSF shunt placement in 16 cases, surgical repair of the sellar floor in three, and both procedures in the remaining 13. Two patients refused any surgical treatment. CONCLUSIONS: The role of increased ICP in the pathogenesis and perpetuation of primary ESS has been confirmed. Adverse neurological signs and a CSF leak are correlated with an actual increase in ICP and are relieved after CSF shunt insertion. Cerebrospinal fluid rhinorrhea is more common than generally thought. Its resolution can be achieved using a careful diagnostic protocol and sometimes may require different surgical procedures.

Adolescent↗
PubMed2004

Motoneurons innervating facial muscles after hypoglossal and hemihypoglossal-facial nerve anastomosis in rats.

Hypoglossal-facial nerve anastomosis (HFA) is the most popular surgical procedure to reinnervate facial muscles after injury of the facial nerve. Section of the hypoglossus causes paralysis and atrophy of the hemi-tongue. In the attempt to overcome this consequence, the hemihypoglossal-facial nerve anastomosis (HHFA) has been proposed and only a half of the main trunk of the hypoglossus is connected to the distal stump of the facial nerve. In the rat, we have studied experimentally the anatomical nuclear changes after HFA and HHFA with the aim of establishing the quantitative motoneuron innervation of facial muscles obtained with each one of the two operative options. Horseradish peroxidase (HRP) injected in both types of anastomosis labeled not only hypoglossal motoneurons, but also facial motoneurons. HFA appeared to offer a significant quantitative motoneuron innervation higher than HHFA and then a higher probable better functional recovery. Both HFA and HHFA performed immediately after section of the facial nerve in rats did not result in a phenomenon of motor hyperinnervation. In our experimental model, the proximal facial nerve stump was coagulated at the stylomastoid foramen to avoid regeneration. Then, the labeled motoneurons into the facial nucleus could really be the expression of axonal projections from facial motoneurons to the hypoglossus nerve and facial muscles. No labeled motoneurons were seen contralaterally as we observed previously after section and repair of several nerves.

Anastomosis, Surgical↗
PubMed2004

The role of transsphenoidal surgery in the treatment of craniopharyngiomas.

OBJECT: The optimal approach for the surgical treatment of craniopharyngiomas is still debated. In all cases involving the sella turcica, the authors have exclusively used transsphenoidal surgery (TSS), assuming that this approach is less traumatic than an intracranial one. Moreover, TSS was also performed in some cases of purely suprasellar craniopharyngiomas. In this study the surgical indications and the results obtained in all patients who had undergone TSS were analyzed. METHODS: In a series of 92 patients who underwent surgery for craniopharyngiomas, TSS was the first choice of approach in 57 cases (62%) consisting of 29 female and 28 male patients with ages ranging from 12 to 79 years (mean 35 years). The follow-up duration ranged from 2 to 20 years. A standard transsphenoidal approach was used in patients with an exclusively intrasellar (11 patients) or an intrasellar and suprasellar tumor (37 patients); in nine cases of tumors located exclusively above the sella turcica, a transsphenoidal presellar approach (seven patients) or a transsellar-transdiaphragmatic approach (two patients) was used. Total removal was performed in 36 patients (63%). All patients had good clinical results. Postoperative cerebrospinal fluid leakage occurred in 10 cases, but only one case required a surgical repair of the sella. Two patients died of late complications (3.5%). There were eight cases (14%) of tumor regrowth. CONCLUSIONS: The authors assert that, when used in appropriately located craniopharyngiomas and by neurosurgeons with extensive experience in pituitary surgery, TSS offers excellent results with minor risks.

Adolescent↗
PubMed2004

Role of apoptosis in intracranial aneurysm rupture.

OBJECT: Mechanisms involved in the rupture of intracranial aneurysms remain unclear, and the literature on apoptosis in these lesions is extremely limited. The hypothesis that apoptosis may reduce aneurysm wall resistance, thus contributing to its rupture, warrants investigation. The authors in this study focused on the comparative evaluation of apoptosis in ruptured and unruptured intracranial aneurysms. Peripheral arteries in patients harboring the aneurysms and in a group of controls were also analyzed. METHODS: Between September 1999 and February 2002, specimens from 27 intracranial aneurysms were studied. In 13 of these patients apoptosis was also evaluated in specimens of the middle meningeal artery (MMA) and the superficial temporal artery (STA). The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique was used to study apoptosis via optical microscopy; electron microscopy evaluation was performed as well. Apoptotic cell levels were related to patient age and sex, aneurysm volume and shape, and surgical timing. Significant differences in apoptosis were observed when comparing ruptured and unruptured aneurysms. High levels of apoptosis were found in 88% of ruptured aneurysms and in only 10% of unruptured lesions (p < 0.001). Elevated apoptosis levels were also detected in all MMA and STA specimens obtained in patients harboring ruptured aneurysms, whereas absent or very low apoptosis levels were observed in MMA and STA specimens from patients with unruptured aneurysms. A significant correlation between aneurysm shape and apoptosis was found. CONCLUSIONS: In this series, aneurysm rupture appeared to be more related to elevated apoptosis levels than to the volume of the aneurysm sac. Data in this study could open the field to investigations clarifying the causes of aneurysm enlargement and rupture.

Adult↗
PubMed2004

The PPARgamma ligands PGJ2 and rosiglitazone show a differential ability to inhibit proliferation and to induce apoptosis and differentiation of human glioblastoma cell lines.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is involved in the control of cell proliferation, apoptosis and differentiation in various tumor cells. Among PPARgamma ligands, 15-deoxy-Delta12,14-prostaglandin J2 (PGJ2), the ultimate metabolite of PGD2, plays a role in the biology of brain tumors. It is still unclear to which extent the anti-proliferative and differentiation-promoting activity of PGJ2 is mediated through PPARgamma. We compared the effects of PGJ2 with those of rosiglitazone - the synthetic agonist with the highest affinity for PPARgamma - in 4 human glioblastoma cell lines (A172, U87-MG, M059K, M059J). All cell lines expressed high levels of PPARgamma, consistent with the high levels of PPARgamma protein in 5 tumor samples. Both PGJ2 and rosiglitazone inhibited proliferation of all cell lines with a G2/M arrest and apoptosis, but only PGJ2 up-regulated p21Cip/WAF1. The growth inhibitory effect was partially reversed by the PPARgamma antagonist GW9662. We studied the time sequence of selected molecular events, that lead glioblastoma cells to apoptosis and/or differentiation, after treatment with both agonists. M059K cells committed to undergo apoptosis by PGJ2, initially up-regulated PPARgamma, and then down-regulated PPARgamma as they began apoptosis. Apoptotic cells also increased their expression of retinoic acid receptor beta (RARbeta) and retinoid X receptor alpha (RXRalpha). PGJ2 increased expression of glial fibrillary acidic protein (GFAP) and decreased levels of vimentin, structural proteins modulated during astrocytic differentiation. Unexpectedly, PGJ2 up-regulated the expression of cyclooxygenase-2 (COX-2). Rosiglitazone caused the same pattern of PPARgamma, RARbeta and RXRalpha expression as PGJ2, but no significant modulation of p21Cip/WAF1, cytoskeletal proteins or COX-2 occurred. Our data indicate that PGJ2, and rosiglitazone suppress cell proliferation and cause apoptosis in glioblastoma cell lines, most likely through a PPARgamma-dependent pathway. By contrast, the modulation of differentiation-associated proteins by PGJ2, but not rosiglitazone, suggests that PGJ2 promotes differentiation of glioblastoma cells independently of PPARgamma activation.

Apoptosis↗
PubMed2003

Pharmacokinetics of temozolomide given three times a day in pediatric and adult patients.

PURPOSE: To characterize and compare pharmacokinetic parameters in children and adults treated with temozolomide (TMZ) administered for 5 days in three doses daily, and to evaluate the possible relationship between AUC values and hematologic toxicity. METHODS: TMZ pharmacokinetic parameters were characterized in pediatric and adult patients with primary central nervous system tumors treated with doses ranging from 120 to 200 mg/m2 per day, divided into three doses daily for 5 days. Plasma levels were measured over 8 h following oral administration in a fasting state. A total of 40 courses were studied in 22 children (mean age 10 years, range 3-16 years) and in 8 adults (mean age 30 years, range 19-54 years). RESULTS: In all patients, a linear relationship was found between systemic exposure (AUC) and increasing doses of TMZ. Time to peak concentration, elimination half-life, apparent clearance and volume of distribution were not related to TMZ dose. No differences were seen among TMZ C(max), t(1/2), V(d) or CL/F in children compared with adults. Intra- and interpatient variability of systemic exposure were limited in both children and adults. No statistically significant differences were found between the AUCs of children who experienced grade 4 hematologic toxicity and children who did not. CONCLUSIONS: No difference appears to exist between pharmacokinetic parameters in adults and children when TMZ is administered in three doses daily. Hematologic toxicity was not related to TMZ AUC. AUC measurement does not appear to be of any use in optimizing TMZ treatment.

Administration, Oral↗