Byung-Kyu Cho

Human Neural Stem Cells Target Experimental Intracranial Medulloblastoma and Deliver a Therapeutic Gene Leading to Tumor Regression

Purpose: Medulloblastoma, a malignant pediatric brain tumor, is incurable in about one third of patients despite multimodal treatments. In addition, current therapies can lead to long-term disabilities. Based on studies of the extensive tropism of neural stem cells (NSC) toward malignant gliomas and the secretion of growth factors common to glioma and medulloblastoma, we hypothesized that NSCs could target medulloblastoma and be used as a cellular therapeutic delivery system. Experimental Design: The migratory ability of HB1.F3 cells (an immortalized, clonal human NSC line) to medulloblastoma was studied both in vitro and in vivo. As proof-of-concept, we used HB1.F3 cells engineered to secrete the prodrug activating enzyme cytosine deaminase. We investigated the potential of human NSCs to deliver a therapeutic gene and reduce tumor growth. Results: The migratory capacity of HB1.F3 cells was confirmed by an in vitro migration assay, and corroborated in vivo by injecting chloromethylbenzamido-Dil–labeled HB1.F3 cells into the hemisphere contralateral to established medulloblastoma in nude mice. In vitro studies showed the therapeutic efficacy of HB1.F3-CD on Daoy cells in coculture experiments. In vitro therapeutic studies were conducted in which animals bearing intracranial medulloblastoma were injected ipsilaterally with HB1.F3-CD cells followed by systemic 5-flourocytosine treatment. Histologic analyses showed that human NSCs migrate to the tumor bed and its boundary, resulting in a 76% reduction of tumor volume in the treatment group (P < 0.01). Conclusion: These studies show for the first time the potential of human NSCs as an effective delivery system to target and disseminate therapeutic agents to medulloblastoma.

Moyamoya disease among young patients: its aggressive clinical course and the role of active surgical treatment.

OBJECTIVEThe prognosis for moyamoya disease (MMD) among young patients is known to be worse than that among older patients. The aim of this study was to investigate the clinical features and treatment outcomes of young patients with MMD. METHODSA total of 204 patients with MMD who underwent encephaloduroarteriosynangiosis, with or without bifrontal encephalogaleosynangiosis, were categorized into three groups according to their ages at the time of surgery, i.e., Group A (n = 23, <3 yr of age), Group B (n = 50, 3–6 yr of age), and Group C (n = 131, >6 yr of age). For each group, patterns of presentation and the occurrence of subsequent preoperative or surgery-related infarctions were assessed. Clinical outcomes and postoperative hemodynamic status were analyzed. RESULTSAt initial presentation, infarctions were significantly more frequent in Group A (87%) and Group B (58%) than in Group C (46%). Subsequent preoperative infarctions occurred significantly more frequently in Group A (39%) than in Group B (6%) or Group C (0.8%). The median interval between the onset of symptoms and a subsequent preoperative infarction was 3 months (range, 1–14 mo). No significant difference in the rates of surgery-related infarctions among the three groups was observed. The rate of favorable clinical outcomes was significantly lower in Group A (58%) than in Group B (84%) or Group C (86%), although the rates of postoperative hemodynamic improvements were similar among the groups. The poor clinical outcomes for Group A were caused mainly by preoperative infarctions. CONCLUSIONYoung-age MMD demonstrates rapid disease progression and results in poor clinical outcomes. These findings indicate the necessity of early surgery for young patients with MMD; however, the actual benefits should be verified with additional controlled studies, with long-term follow-up monitoring.

Intracranial Ganglioglioma: Preoperative Characteristics and Oncologic Outcome after Surgery

In order to investigate the clinical characteristics, neuroimaging findings, pathological features, treatment, and outcomes, and to provide valuable guidance for the diagnosis and management of intracranial gangliogliomas, 34 cases of intracranial gangliogliomas were retrospectively analyzed.This study included 23 males and 11 females. Age at operation ranged from 17 days to 50 years. All patients had preoperative magnetic resonance imaging (MRI). Computed tomography (CT), magnetic resonance spectroscopy (MRS), 18F-FDG–PET (positron emission tomography), and 99Tc-HMPAO-SPECT (single photon emission computed tomography) were also performed in some cases. All pathological specimens and all available neuroimages were re-evaluated. The follow-up period varied from 12 to 89 months (mean 36 months). Seizure was the most common presenting symptom (85%). Tumor calcification was detected by CT scan in six of 11 cases. Seventeen gangliogliomas (50%) showed cystic components and 18 tumors (53%) were enhanced on MRI. All temporal lobe gangliogliomas were located intracortically and most of them had poor demarcation on MRI. In comparison with the contralateral normal area, the gangliogliomas showed a reduced Cho/Cr and NAA/Cr ratio, and an increased Cho/NAA ratio. On 18F-FDG-PET, gangliogliomas were usually hypometabolic. HMPAO-SPECT indicated tumor hypoperfusion or isoperfusion. A gross total resection was achieved in 25 patients. Tumor progression was observed in three patients who underwent an incomplete tumor resection. Two of them underwent a malignant transformation to a glioblastoma. Twenty-seven patients could carry on their normal life activity with the Karnofsky Performance Scale (KPS) of more than 80.Even though ganglioglioma is a slowly growing benign tumor, which could be demonstrated by magnetic resonance spectroscopy (MRS), PET, and SPECT, there is a chance of malignant transformation, especially in cases of incomplete tumor resection. Gangliogliomas should be resected gross totally, if feasible, to achieve the best long-term outcomes.

Pediatric moyamoya disease: An analysis of 410 consecutive cases

Moyamoya disease (MMD) is a cerebrovascular occlusive disease of the bilateral internal carotid arteries that causes a compensatory abnormal vascular network at the base of brain. The rare incidence and various surgical techniques applied have limited the clinical research on MMD.

Targeting Rat Brainstem Glioma Using Human Neural Stem Cells and Human Mesenchymal Stem Cells

Purpose: Brainstem gliomas are usually inoperable and have a dismal prognosis. Based on the robust tropisms of neural stem cells (NSC) and mesenchymal stem cells (MSC) to brain tumors, we compared the tumor-tropic migratory capacities of these stem cells and evaluated the therapeutic potential of genetically engineered human NSCs encoding cytosine deaminase (CD) and IFNβ against brainstem gliomas. Experimental Design: The directed migratory capacities of NSCs and MSCs to brainstem glioma (F98) were evaluated both in vitro and in vivo. The human NSCs (HB1.F3) and various human MSCs, such as bone marrow–derived MSCs (HM3.B10), adipose tissue–derived MSCs, and umbilical cord blood–derived MSCs, were tested. Human fibroblast cells (HFF-1) were used as the negative control. As a proof of concept, the bioactivity of HB1.F3-CD-IFNβ was analyzed with a cell viability assay, and animals with brainstem gliomas were injected with HB1.F3-CD-IFNβ cells followed by systemic 5-fluorocytosine treatment. Results: In an in vitro modified Transwell migration assay and in vivo stem cell injection into established brainstem gliomas in rats, all the stem cells showed a significant migratory capacity compared with that of the control (P < 0.01). Histologic analysis showed a 59% reduction in tumor volume in the HB1.F3-CD-IFNβ–treated group (P < 0.05). Apoptotic cells were increased 2.33-fold in animals treated with HB1.F3-CD-IFNβ compared with the respective control groups (P < 0.01). Conclusion: The brainstem glioma-tropic migratory capacities of MSCs from various sources were similar to those of NSCs. Genetically engineered NSCs show therapeutic efficacy against brainstem gliomas.

Pineal tumors: experience with 48 cases over 10 years

Abstract The authors retrospectively reviewed 48 patients treated at Seoul National University Hospital (SNUH) between 1986 and 1995. There were 35 children and 13 adults, accounting for 10.1% of 345 pediatric and 0.68% of 1914 adult brain tumors in SNUH during the same period. The 48 cases consisted of 33 cases of germ cell tumor (69%, GCT); 6 of pineoblastoma (PB, 12.5%); 3 of pineocytoma (PC, 6.3%); 3 of anaplastic astrocytoma (6.3%); 1 of astrocytoma; 1 of glioblastoma; and 1 of ependymoma. The median age was 13 years (range 1–59) and the male-to-female ratio was 3.36:1. The most frequent presenting symptom was due to increased intracranial pressure (90%), followed by Parinaud syndrome or diplopia (50%). Patients with a benign tumor, such as teratoma (TE), astrocytoma, or ependymoma, underwent surgery by the occipital transtentorial approach (OTT) for attempted radical resection without adjuvant therapy, while patients with immature teratoma (imTE), PC, and anaplastic astrocytoma underwent regional radiotherapy (RT) after debulking via OTT. Seven patients with nongerminomatous malignant GCT (NG-MGCT) and 3 with germinoma (GE) underwent craniospinal radiation only, 6 with GE, a NG-MGCT, and 2 with GE+TE received craniospinal radiotherapy (CSRT) after debulking via OTT. Three patients with GE, 4 with NG-MGCT, and 3 with PB underwent radiochemotherapy after debulking via OTT. Forty-four patients were followed up after treatment. The median follow-up period was 36 months. All patients with GE were alive after RT at 36 months (median) of follow-up (range 7–70 months). All with GE+TE and TE were alive. Three patients with PC or astrocytoma were also alive with stable or no evidence of disease. In 1 of the 3 cases of imTE there was a recurrence. However, 4 patients with NG-MGCT died, all of whom had undergone CSRT only; 2 PB patients were alive (12, 19 months), 1 in a moribund status (36 months), and 2 were dead (6, 60 months). The overall mean survival time with pineal tumors was 66 months and the 3-year survival rate was 84% with minimal posttreatment complications. It is concluded that pineal region tumors have male and childhood predominances, and the most common tumor is GCT. The majority of pineal region tumors are malignant. Pineal region tumors can be approached safely and effectively and the surgical complications are mostly transient. Their prognosis is dependent on the pathologies and treatment modalities.

Dysembryoplastic neuroepithelial tumor: radiological findings (including PET, SPECT, and MRS) and surgical strategy.

In order to elucidate the radiological features of dysembryoplastic neuroepithelial tumor (DNT), and to clarify the optimal surgical strategy for this tumor, the authors retrospectively analyzed 20 cases of DNT treated at our institution.Magnetic resonance (MR) imaging (all cases), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) (eight cases), ictal/interictal Tc99m-HMPAO single photon emission computed tomography (SPECT) (seven and five cases respectively) and proton magnetic resonance spectroscopy (1H MRS) (one case) were performed preoperatively. Invasive monitoring/intraoperative electrocorticography (ECoG) was performed in four cases in order to determine the epileptogenic zone. A well-demarcated lobulating tumor located in the cortical with/without subcortical area was the typical MR finding. 18F-FDG PET showed glucose hypometabolism in all cases. Ictal Tc99m-HMPAO SPECT showed hyperperfusion of the lesion in three cases and interictal Tc99m-HMPAO SPECT showed hypoperfusion of the lesion in one case. 1H MRS showed nonspecific findings. Gross total resection was performed in all cases. Histologically, associated cortical dysplasia was found in 11 cases. The mean duration of follow-up after surgery was 37.9 months, and the overall seizure free rate was 90%. Follow-up MR imaging was performed in 14 cases (mean duration of follow-up: 21.6 months) and showed no recurrence of tumor in any of these cases. lnvasive monitoring/intraoperative ECoG and the presence of cortical dysplasia showed no significant relationship with seizure control rate (p=1.25 and p=1.62 respectively).

Sox2 Expression in Brain Tumors : A Reflection of the Neuroglial Differentiation Pathway

Sox2 is a key transcription factor that maintains the proliferation of neuroglial stem cells and inhibits neuronal fate commitment. Moreover, it was recently found that brain tumors contain stem cells that resemble normal neuroglial stem cells in many respects. This study was undertaken to describe Sox2 expression in various brain tumors, and to determine whether Sox2 expression is a universal feature of brain tumors, or whether its expression is limited to a specific lineage of brain tumors. Sox2 immunohistochemistry was performed on 194 brain tumor tissues of various kinds. Fetal and adult normal brain tissues obtained by autopsy and brain tissues of epilepsy patients with cortical dysplasia were used as controls. Semiquantitative reverse transcription polymerase chain reaction was used to confirm the immunohistochemical results. Double immunofluorescence was performed to characterize the lineage of Sox2-positive cells. Sox2 was found to be expressed in various glial tumors, including those with astroglial, oligodendroglial, and ependymal lineages, and in the glial components of mixed neuroglial tumors, regardless of pathologic grade. In brain tumors of embryonal origin, supratentorial primitive neuroectodermal tumors showed robust Sox2 expression, whereas medulloblastomas and pineoblastomas did not. The majority of Sox2-positive tumor cells coexpressed glial fibrillary acidic protein, and most Sox2-negative cells in medulloblastomas and pineoblastomas showed neuronal differentiation. This study suggest that Sox2 may be a tumor marker of glial lineages rather than a universal brain tumor stem cell marker, because its expression pattern was found to correspond to differentiation pathways. On the other hand, the aberrant coexpressions of Sox2 and of a neuronal marker were widely observed in glioblastomas, which reflects a disorganized differentiation pattern that characterizes highly malignant tumors.

Therapeutic efficacy and safety of TRAIL- producing human adipose tissue-derived mesenchymal stem cells against experimental brainstem glioma

Mesenchymal stem cells (MSCs) have an extensive migratory capacity for gliomas, which is comparable to that of neural stem cells. Among the various types of MSCs, human adipose tissue-derived MSCs (hAT-MSC) emerge as one of the most attractive vehicles for gene therapy because of their high throughput, lack of ethical concerns, and availability and ease of isolation. We evaluated the therapeutic potential and safety of genetically engineered hAT-MSCs encoding the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) against brainstem gliomas. Human AT-MSCs were isolated from human fat tissue, characterized, and transfected with TRAIL using nucleofector. The therapeutic potential of TRAIL-producing hAT-MSCs (hAT-MSC.TRAIL) was confirmed using in vitro and in vivo studies. The final fate of injected hAT-MSCs was traced in long-survival animals. The characterization of hAT-MSCs revealed the expression of MSC-specific cell-type markers and their differentiation potential into mesenchymal lineage. Short-term outcomes included a 56.3% reduction of tumor volume (P < .001) with increased apoptosis (3.03-fold, P < .05) in animals treated with hAT-MSC.TRAIL compared with the control groups. Long-term outcomes included a significant survival benefit in the hAT-MSC.TRAIL-treated group (26 days of median survival in the control group vs 84 days in the hAT-MSC.TRAIL-treated group, P < .0001), without any evidence of mesenchymal differentiation in vivo. Our study demonstrated the therapeutic efficacy and safety of nonvirally engineered hAT-MSCs against brainstem gliomas and showed the possibility of stem-cell-based targeted gene therapy for clinical application.

Prediction of the Clinical Outcome of Pediatric Moyamoya Disease With Postoperative Basal/Acetazolamide Stress Brain Perfusion SPECT After Revascularization Surgery

Background and Purpose— We evaluated whether basal/acetazolamide stress brain perfusion SPECT performed after revascularization surgery can predict the further clinical outcome of patients with pediatric moyamoya disease. Methods— A total of 77 (31 males, 46 females, age 6.6±3.2 years) patients with postoperative pediatric moyamoya disease who underwent basal/acetazolamide stress brain perfusion SPECT 6 to 12 months after revascularization surgery and who were followed-up >12 months after SPECT were included. Mean follow-up period after SPECT was 36±19 months. Sixty-two patients underwent bilateral ribbon encephaloduroarteriosynangiosis (EDAS), 14 bilateral EDAS, and 1 unilateral EDAS. Ordinal logistic regression analysis using 5 independent variables (infarction on preoperative MRI, age at the first operation, highest Suzuki stage on cerebral angiography, and regional cerebrovascular reserve on postoperative SPECT) against postoperative clinical outcomes was performed. Results— Fifty-one patients had preserved reserve on postoperative SPECT and their clinical outcomes were excellent (30), good (15), fair (4), and poor (2); 26 patients had decreased reserve (excellent, 1; good, 7; fair, 14; poor, 4). On ordinal logistic regression analysis, age at the first operation (P=0.033) and reserve on postoperative SPECT (P<0.001) were statistically significant. Conclusion— Basal/acetazolamide stress brain perfusion SPECT performed at 6 to 12 months after the indirect bypass operation could predict the further clinical outcome of pediatric patients with moyamoya disease. Patients with decreased cerebrovascular reserve will have remaining neurological deficit and ischemic attacks on follow-up.