RESUMO
von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary cancer disorder caused by a germline mutation in the VHL tumor suppressor gene. Loss of the wild-type allele results in VHL deficiency and the potential formation of cerebellar hemangioblastomas, which resemble embryonic hemangioblast proliferation and differentiation processes. Multiple, microscopic, VHL-deficient precursors, termed developmentally arrested structural elements (DASEs), consistently involve the cerebellar molecular layer in VHL patients, indicating the tumor site of origin. Unlike hemangioblastomas, however, cerebellar DASEs do not express brachyury, a mesodermal marker for hemangioblasts. In this study, neuronal progenitors occupying the molecular layer were investigated as tumor cells of origin. By immunohistochemistry, cerebellar DASEs and hemangioblastomas lacked immunoreactivity with antibody ZIC1 (Zic family member 1), a granule cell progenitor marker with concordance from oligonucleotide RNA expression array analyses. Rather, cerebellar DASEs and hemangioblastomas were immunoreactive with antibody PAX2 (paired box 2), a marker of basket/stellate cell progenitors. VHL cerebellar cortices also revealed PAX2-positive cells in Purkinje and molecular layers, resembling the histological and molecular development of basket/stellate cells in postnatal non-VHL mouse and human cerebella. These data suggest that VHL deficiency can result in the developmental arrest of basket/stellate cells in the human cerebellum and that these PAX2-positive, initiated cells await another insult or signal to form DASEs and eventually, tumors.
Assuntos
Neoplasias Cerebelares , Hemangioblastoma , Doença de von Hippel-Lindau , Animais , Camundongos , Recém-Nascido , Humanos , Hemangioblastoma/genética , Hemangioblastoma/metabolismo , Hemangioblastoma/patologia , Doença de von Hippel-Lindau/complicações , Doença de von Hippel-Lindau/genética , Doença de von Hippel-Lindau/metabolismo , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Cerebelo/patologia , Oligonucleotídeos/metabolismo , RNA/metabolismo , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismoRESUMO
BACKGROUND: Pre-operative detection of corticotropin (ACTH) secreting microadenomas causing Cushing's disease (CD) improves surgical outcomes. Current best magnetic resonance imaging fails to detect up to 40% of these microadenomas. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is specific, but not sensitive in detecting corticotropinomas. Theoretically, secretagogue stimulation with corticotropin releasing hormone (CRH) could improve detection of adenomas with 18F-FDG PET. Previous attempts with simultaneous CRH stimulation have failed to demonstrate increased 18F-FDG uptake in corticotropinomas. We hypothesized that CRH stimulation leads to a delayed elevation in glucose uptake in corticotropinomas. METHODS: Clinical data was analyzed for efficacy of CRH in improving 18FDG-PET detection of corticotropinomas in CD. Glucose transporter 1 (GLUT1) immunoreactivity was performed on surgical specimens. Ex-vivo, viable cells from these tumors were tested for secretagogue effects (colorimetric glucose uptake), and for fate of intracellular glucose (glycolysis stress analysis). Validation of ex-vivo findings was performed with AtT-20 cells. RESULTS: CRH increased glucose uptake in human-derived corticotroph tumor cells and AtT-20, but not in normal murine or human corticotrophs (p < 0.0001). Continuous and intermittent (1 h) CRH exposure increased glucose uptake in AtT-20 with maximal effect at 4 h (p = 0.001). Similarly, CRH and 8-Br-cAMP led to robust GLUT1 upregulation and increased membrane translocation at 2 h, while fasentin suppressed baseline (p < 0.0001) and CRH-mediated glucose uptake. Expectedly, intra-operatively collected corticotropinomas demonstrated GLUT1 overexpression. Lastly, human derived corticotroph tumor cells demonstrated increased glycolysis and low glucose oxidation. CONCLUSION: Increased and delayed CRH-mediated glucose uptake differentially occurs in adenomatous corticotrophs. Delayed secretagogue-stimulated 18F-FDG PET could improve microadenoma detection.
Assuntos
Adenoma Hipofisário Secretor de ACT/metabolismo , Hormônio Liberador da Corticotropina/farmacologia , Transportador de Glucose Tipo 1/metabolismo , Glucose/metabolismo , Animais , Arginina Vasopressina/farmacologia , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Corticotrofos/metabolismo , Dexametasona/farmacologia , Transportador de Glucose Tipo 1/genética , Glicólise/efeitos dos fármacos , Humanos , Camundongos , Transporte Proteico/efeitos dos fármacos , Ovinos , Transcrição Gênica/efeitos dos fármacosRESUMO
Von Hippel-Lindau (VHL)-associated hemangioblastomas (VHL-HB) arise in the central nervous system (CNS), and are a leading cause of morbidity and mortality in VHL disease. Currently, surgical resection is the most effective way to manage symptomatic VHL-HBs. Surgically unresectable VHL-HBs or those in frail patients are challenging problems. Therapies targeting oncologic and vascular endothelial growth factor (VEGF) pathways have failed to demonstrate tumor control. Our experience and previous reports on VHL-HB avidity to somatostatin analogues suggested somatostatin receptor (SSTR) expression in VHL-HBs, offering an alternative therapeutic strategy. We explored this possibility by demonstrating consistent histologic expression of SSTR1, 2a, 4, and 5 in VHL-HBs. We found that somatostatin analogue octreotide induces apoptosis in VHL-HB stromal cells in a dose-dependent fashion by BAX - caspase-3 pathway unrelated to canonical VHL pathway. When administered to a patient with unresectable symptomatic suprasellar hemangioblastoma, octreotide resulted in tumor volume reduction, symptom stabilization, and tumor cytopenia on repeat 68Ga-DOTA-TATE positron emission tomography (PET) within 6 months, suggesting tumor infarction. We conclude that VHL-HBs harbor multiple SSTR subtypes that offer actionable chemo-therapeutic strategy for management of symptomatic, unresectable tumors by somatostatin analogue therapy.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Hemangioblastoma/tratamento farmacológico , Octreotida/farmacologia , Receptores de Somatostatina/genética , Doença de von Hippel-Lindau/tratamento farmacológico , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/patologia , Células Cultivadas , Feminino , Hemangioblastoma/patologia , Humanos , Pessoa de Meia-Idade , Octreotida/análogos & derivados , Octreotida/uso terapêutico , Compostos Organometálicos/uso terapêutico , Compostos Radiofarmacêuticos/uso terapêutico , Receptores de Somatostatina/agonistas , Receptores de Somatostatina/metabolismo , Doença de von Hippel-Lindau/patologiaRESUMO
von Hippel-Lindau (VHL) patients develop multiple central nervous system hemangioblastomas (HB). Some HBs become symptomatic with exponential growth or cyst formation following long periods of quiescence. Understanding the factors underlying growth in hemangioblastoma may lead to better strategies to arrest or prevent tumor growth. In 5 VHL patients, we resected quiescent hemangioblastomas (Q-HB) that were en-route during surgical access to symptomatic hemangioblastomas (S-HB), for matched tumor analysis. Quantitative reverse transcriptase analysis demonstrated a 2-fold increase in EPO expression in all S-HB, while 4/5 showed either Hypoxia Inducible Factor-1α or 2α upregulation. Additionally, all S-HB had increased phosphorylated erythropoietin (EPO) receptor and phosphorylated STAT-5 relative to matched Q-HB, with increased phosphorylated JAK-2 largely confined to the stromal cells in clusters within the tumors. These findings suggest that Q-HB to S-HB conversion may be associated with an erythropoietin-signaling loop. Furthermore, we found that EPO is detectable in cyst fluid from S-HB (n = 14), while absent in CSF (n = 1). Additionally, S-HB presentation or S-HB resection does not result in discernible change in serum EPO or hemoglobin (n = 60). These observations suggest that the altered erythropoietin signaling is focal and suggests that studying modulation of erythropoietin receptor pathway may lead to strategies in preventing HB growth.
Assuntos
Eritropoetina/metabolismo , Hemangioblastoma/etiologia , Hemangioblastoma/metabolismo , Transdução de Sinais , Doença de von Hippel-Lindau/etiologia , Doença de von Hippel-Lindau/metabolismo , Adulto , Biomarcadores , Feminino , Hemangioblastoma/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia , Índice de Gravidade de Doença , Doença de von Hippel-Lindau/diagnósticoRESUMO
Transcription factors that induce epithelial-mesenchymal transition (EMT) promote invasion, chemoresistance and a stem-cell phenotype in epithelial tumors, but their roles in central nervous system tumors are not well-understood. We hypothesized these transcription factors have a functional impact in grades II-III gliomas. Using the National Cancer Institute (NCI) Repository for Molecular Brain Neoplasia Data (REMBRANDT) and the Cancer Genome Atlas (TCGA) Lower-Grade Glioma (LGG) data, we determined the impact of EMT-promoting transcription factors (EMT-TFs) on overall survival in grades II-III gliomas, compared their expression across common genetic subtypes and subsequently validated these findings in a set of 31 tumors using quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Increased expression of the gene coding for the transcriptional repressor Zinc Finger E box-binding Homeobox 1 (ZEB1) was associated with a significant increase in overall survival (OS) on Kaplan-Meier analysis. Genetic subtype analysis revealed that ZEB1 expression was relatively increased in IDH1/2-mutant gliomas, and IDH1/2-mutant gliomas expressed significantly lower levels of many ZEB1 transcriptional targets. Similarly, IDH1/2-mutant tumors expressed significantly higher levels of targets of microRNA 200C (MIR200C), a key regulator of ZEB1. In a validation study, ZEB1 mRNA was significantly increased in IDH1-mutant grades II-III gliomas, and ZEB1 protein expression was more pronounced in these tumors. Our findings demonstrate a novel relationship between IDH1/2 mutations and expression of ZEB1 and its transcriptional targets. Therapy targeting ZEB1-associated pathways may represent a novel therapeutic avenue for this class of tumors.
Assuntos
Neoplasias Encefálicas/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Glioma/metabolismo , Isocitrato Desidrogenase/genética , Mutação/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/mortalidade , Bases de Dados Factuais/estatística & dados numéricos , Feminino , Glioma/genética , Glioma/mortalidade , Humanos , Isocitrato Desidrogenase/metabolismo , Estimativa de Kaplan-Meier , Masculino , RNA Mensageiro/metabolismo , Estatística como AssuntoRESUMO
OBJECT: Pituitary adenomas occasionally undergo infarction, apoplexy, which often destroys much of the tumor. It is well known that apoplexy can be precipitated by several acute factors, including cardiac surgery, other types of surgery, trauma, insulin infusion, and stimulation with administration of hypothalamic releasing factors. METHODS: The prior focus on mechanisms underlying pituitary apoplexy has been on these acute events. Less attention has been given to the endogenous features of pituitary tumors that make them susceptible to spontaneous infarction, despite that most pituitary apoplexy occurs in the absence of a recognized precipitating event. The authors examine intrinsic features of pituitary adenomas that render them vulnerable to apoplexy-features such as high metabolic demand, paucity of angiogenesis, and sparse vascularity, qualities that have previously not been linked with apoplexy-and argue that it is these features of adenomas that underlie their susceptibility to spontaneous infarction. The sensitivity of freshly cultured pituitary adenomas to hypoglycemia is assessed. RESULTS: Adenomas have high metabolic demand, limited angiogenesis, and reduced vessel density compared with the normal gland. Pituitary adenoma cells do not survive in the presence of reduced or absent concentrations of glucose. CONCLUSIONS: The authors propose that the frequent ischemic infarction of pituitary adenomas is the product of intrinsic features of these tumors. These endogenous qualities create a tenuous balance between high metabolic demand and marginal tissue perfusion. Thus, the tumor is vulnerable to spontaneous infarction or to acute ischemia by any event that acutely alters the balance between tumor perfusion and tumor metabolism, events such as acute systemic hypotension, abruptly decreased supply of nutrients, hypoglycemia with insulin administration, or increase in the tumor's metabolic demand due to administration of hypothalamic releasing factors. It may be possible to take advantage of these intrinsic features of pituitary adenomas by using aspects of this vulnerability for development of new approaches for treatment.
Assuntos
Adenoma/patologia , Apoplexia Hipofisária/patologia , Neoplasias Hipofisárias/patologia , Adenoma/metabolismo , Adenoma/cirurgia , Metabolismo Energético/fisiologia , Glucose/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Apoplexia Hipofisária/metabolismo , Apoplexia Hipofisária/cirurgia , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/cirurgiaRESUMO
von Hippel-Lindau disease (VHL) patients develop highly vascular tumors, including central nervous system hemangioblastomas. It has been hypothesized that the vascular nature of these tumors is the product of reactive angiogenesis. However, recent data indicate that VHL-associated hemangioblastoma neoplastic cells originate from embryologically-arrested hemangioblasts capable of blood and endothelial cell differentiation. To determine the origin of tumor vasculature in VHL-associated hemangioblastomas, we analyzed the vascular elements in tumors from VHL patients. We demonstrate that isolated vascular structures and blood vessels within VHL-associated hemangioblastomas are a result of tumor-derived vasculogenesis. Further, similar to hemangioblastomas, we demonstrate that other VHL-associated lesions possess vascular tissue of tumor origin and that tumor-derived endothelial cells emerge within implanted VHL deficient UMRC6 RCC murine xenografts. These findings further establish the embryologic, developmentally arrested, hemangioblast as the tumor cell of origin for VHL-associated hemangioblastomas and indicate that it is also the progenitor cell for other VHL-associated tumors.
Assuntos
Neoplasias Cerebelares/patologia , Hemangioblastoma/patologia , Doença de von Hippel-Lindau/diagnóstico , Animais , Linhagem Celular Tumoral , Neoplasias Cerebelares/irrigação sanguínea , Neoplasias Cerebelares/etiologia , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Fator VIII/metabolismo , Hemangioblastoma/irrigação sanguínea , Hemangioblastoma/etiologia , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Perda de Heterozigosidade , Masculino , Camundongos , Camundongos Endogâmicos NOD , Neovascularização Patológica , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Transplante Heterólogo , Doença de von Hippel-Lindau/complicações , Doença de von Hippel-Lindau/patologiaRESUMO
OBJECT: The astrocytic contribution to the blood-brain barrier (BBB) in metastatic and primary malignant brain tumors is not well understood. To better understand the vascular properties associated with metastatic and primary malignant brain tumors, the authors systematically analyzed the astrocytic component of the BBB in brain neoplasms. METHODS: Twelve patients who underwent resection of metastatic or primary brain neoplasms (4 metastatic lesions, 2 low-grade astrocytomas, 2 anaplastic astrocytomas, and 4 glioblastoma multiforme) were included. Clinical, MRI, operative, histopathological and immunohistochemical (glial fibrillary acidic protein [GFAP], CD31, and aquaporin 4 [AQ4]) findings were analyzed. RESULTS: Intratumoral regions of MRI enhancement corresponded with breakdown of the normal astrocyte-endothelial cell relationship in the BBB in metastatic deposits and malignant gliomas. Metastases demonstrated lack of perivascular GFAP and AQ4 on CD31-positive intratumoral vessels. At the metastasis-brain interface, normalization of GFAP and AQ4 staining associated with intraparenchymal vessels was observed. Intratumoral vasculature in enhancing regions of high-grade gliomas revealed gaps in GFAP and AQ4 staining consistent with disintegration of the normal astrocyte-endothelial cell association in the BBB. Intratumoral vasculature in low-grade and nonenhancing regions of high-grade gliomas maintained the normal astrocyte-endothelial cell relationship seen in an intact BBB, with GFAP- and AQ4-positive glial processes that were uniformly associated with the CD31-positive vasculature. CONCLUSIONS: Regions of MRI enhancement in metastatic and primary malignancies correspond to areas of breakdown of the physiological astrocyte-endothelial cell relationship of the BBB, including loss of normal perivascular astrocytic architecture on GFAP and AQ4 immunohistochemistry. Nonenhancing areas are associated with preservation of the normal astrocyte-endothelial cell relationship of the intact BBB.
Assuntos
Astrócitos/patologia , Astrocitoma/patologia , Barreira Hematoencefálica/patologia , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Adulto , Idoso , Astrócitos/metabolismo , Astrocitoma/metabolismo , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/secundário , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Glioblastoma/metabolismo , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-IdadeAssuntos
Hemangioblastoma , Mastócitos , Doença de von Hippel-Lindau , Feminino , Hemangioblastoma/genética , Hemangioblastoma/metabolismo , Hemangioblastoma/patologia , Humanos , Masculino , Mastócitos/metabolismo , Mastócitos/patologia , Doença de von Hippel-Lindau/genética , Doença de von Hippel-Lindau/metabolismo , Doença de von Hippel-Lindau/patologiaRESUMO
Carbonic anhydrase (CA) IX is over-expressed in glioblastoma; however, its functions in this context are unknown. Metabolically, glioblastomas are highly glycolytic, leading to a significant lactic acid load. Paradoxically, the intracellular pH is alkaline. We hypothesized that CAIX contributes to the extrusion of hydrogen ions into the extracellular space, thereby moderating intra- and extracellular pH and creating an environment conductive to enhanced invasion. We investigated the role of CAIX as a prognostic marker in patients with glioblastoma and its biological function in vitro. CAIX expression was analyzed in 59 patients with glioblastoma by immunohistochemistry. The expression levels were correlated to overall survival. In vitro, U251 and Ln 18 glioblastoma cells were incubated under hypoxia to induce CAIX expression, and RNA interference (RNAi) was used to examine the function of CAIX on cell attachment, invasion, intracellular energy transfer, and susceptibility to adjuvant treatment. High CAIX expression was identified as an independent factor for poor survival in patients with glioblastoma. In vitro, cell attachment and invasion were strongly reduced after knockdown of CAIX. Finally, the effects of radiation and chemotherapy were strongly augmented after CAIX interference and were accompanied by a higher rate of apoptotic cell death. CAIX is an independent prognostic factor for poor outcome in patients with glioblastoma. Cell attachment, invasion, and survival during adjuvant treatment are significantly influenced by high CAIX expression. These results indicate that inhibition of CAIX is a potential metabolic target for the treatment of patients with glioblastoma.
Assuntos
Biomarcadores Tumorais/análise , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/enzimologia , Anidrase Carbônica IV/metabolismo , Glioblastoma/enzimologia , Western Blotting , Neoplasias Encefálicas/mortalidade , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Feminino , Glioblastoma/mortalidade , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Prognóstico , Interferência de RNARESUMO
OBJECT: Central nervous system hemangioblastomas are the most common manifestation of von Hippel-Lindau (VHL) disease, an autosomal dominant tumor suppressor syndrome that results in loss of VHL protein function and continuous upregulation of hypoxia-inducible factors. These tumors are composed of neoplastic stromal cells and abundant vasculature. Stromal cells express markers consistent with multipotent embryonically arrested hemangioblasts, which are precursors for hematopoietic and vascular lineages. Notch receptors are transmembrane signaling molecules that regulate multiple developmental processes including hematopoiesis and vasculogenesis. To investigate the importance of notch signaling in the development of VHL disease-associated CNS hemangioblastomas, the authors examined the presence of the four notch receptors and downstream notch effectors in this setting. METHODS: The authors used surgical specimens obtained from confirmed VHL-associated hemangioblastomas. Immunohistochemical analysis for the four notch receptors and the downstream effectors was performed on formalin-fixed paraffin-embedded sections. Western blot analysis for HES1 was performed on frozen specimens. RESULTS: All four notch receptors are present in hemangioblastomas. NOTCH1 and NOTCH4 receptors were widely and prominently expressed in both the stromal and vascular cells, NOTCH2 receptor expression was limited to primarily stromal cells, and NOTCH3 receptor expression was limited to vascular cells. All 4 receptors displayed a nuclear presence. Immunohistochemical analysis also demonstrated that downstream notch effectors, HES1 and HES5, were uniformly expressed in tumor stromal and vascular cells, but HES3, HEY1, and HEY2 were not. Strong HES1 expression was confirmed by Western blot analysis. CONCLUSIONS: The presence of all four notch receptors and downstream effector molecules suggests that the notch signaling pathway plays a critical role in the maintenance of the undifferentiated pluripotent phenotype of these tumors and in the associated vascular response. Moreover, the prominent expression of notch receptors in VHL-associated CNS hemangioblastomas reveals a new and possibly potent therapeutic target.
Assuntos
Neoplasias do Sistema Nervoso Central/metabolismo , Hemangioblastoma/metabolismo , Receptores Notch/metabolismo , Doença de von Hippel-Lindau/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ciclo Celular/metabolismo , Neoplasias do Sistema Nervoso Central/patologia , Proteínas de Ligação a DNA/metabolismo , Hemangioblastoma/patologia , Proteínas de Homeodomínio/metabolismo , Humanos , Proteínas Repressoras , Fatores de Transcrição HES-1 , Fatores de Transcrição/metabolismo , Doença de von Hippel-Lindau/patologiaRESUMO
Inactivation of the von Hippel-Lindau (VHL) gene and activation of the hypoxia-inducible factor (HIF) in susceptible cells precedes formation of tumorlets and frank tumor in the epididymis of male VHL patients. We performed detailed histologic and molecular pathologic analysis of tumor-free epididymal tissues from VHL patients to obtain further insight into early epididymal tumorigenesis. Four epididymides from two VHL patients were serially sectioned to allow for three-dimensional visualization of morphologic changes. Areas of interest were genetically analyzed by tissue microdissection, immunohistochemistry for HIF and markers for mesonephric differentiation, and in situ hybridization for HIF downstream target vascular endothelial growth factor. Structural analysis of the epididymides revealed marked deviations from the regular anatomic structure resulting from impaired organogenesis. Selected efferent ductules were represented by disorganized mesonephric cells, and the maldeveloped mesonephric material was VHL-deficient by allelic deletion analysis. Furthermore, we observed maldeveloped mesonephric material near cystic structures, which were also VHL-deficient and were apparent derivatives of maldeveloped material. Finally, a subset of VHL-deficient cells was structurally integrated in regular efferent ductules; proliferation of intraductular VHL-deficient cells manifests itself as papillary growth into the ductular lumen. Furthermore, we clarify that that there is a pathogenetic continuum between microscopic tumorlets and formation of tumor. In multiple locations, three-dimensional reconstruction revealed papillary growth to extend deeply into ductular lumina, indicative of progression into early hamartoma-like neoplasia. We conclude epididymal tumorigenesis in VHL disease to occur in two distinct sequential steps: maldevelopment of VHL-deficient mesonephric cells, followed by neoplastic papillary proliferation.
Assuntos
Epididimo/anormalidades , Doenças dos Genitais Masculinos/complicações , Doenças dos Genitais Masculinos/patologia , Neoplasias dos Genitais Masculinos/etiologia , Hamartoma/etiologia , Doença de von Hippel-Lindau/complicações , Adulto , Autopsia , Proliferação de Células , Cistos/etiologia , Cistos/metabolismo , Cistos/patologia , Progressão da Doença , Epididimo/crescimento & desenvolvimento , Epididimo/metabolismo , Epididimo/patologia , Doenças dos Genitais Masculinos/congênito , Doenças dos Genitais Masculinos/metabolismo , Neoplasias dos Genitais Masculinos/patologia , Hamartoma/patologia , Humanos , Masculino , Proteína Supressora de Tumor Von Hippel-Lindau/metabolismo , Ductos Mesonéfricos/anormalidades , Ductos Mesonéfricos/metabolismo , Ductos Mesonéfricos/patologia , Doença de von Hippel-Lindau/metabolismo , Doença de von Hippel-Lindau/patologiaRESUMO
An adjuvant therapy to prolong the therapeutic window for stroke patients is urgently needed. This randomized, blinded, placebo-controlled study investigated adjuvant intravenous sodium nitrite with recombinant tissue plasminogen activator (rtPA) in middle cerebral artery occlusion (MCAO) with 6 and 2 h of ischemia followed by reperfusion in Sprague-Dawley rats (n=59). Quantitative diffusion, T(1)-, T(2)-weighted, and semiquantitative perfusion imaging were performed before and after reperfusion and at 48 h after ischemia to determine the spatiotemporal evolution of stroke. After 48 h animals were killed and examined to evaluate infarct size and evidence of hemorrhagic transformation. Factor VIII immunostaining was performed to assess vessel morphology. Nitrite treatment (6 h group: 37.5 micromol for more than 90 mins; 2 h group: 26.25 and 1.75 micromol for more than 60 mins) did not reduce infarct volume 48 h after MCAO compared with saline-treated placebo groups after 6 or 2 h of MCAO. Stroke progression from baseline to 48 h, based on the apparent diffusion coefficient and relative cerebral blood flow deficits before and after reperfusion and T(2)-weighted hyperintensity at 48 h, did not differ between treated and control animals. These results suggest that nitrite is not a protective adjuvant therapy to delayed rtPA administration after ischemic stroke in rats.
Assuntos
Nitritos/farmacologia , Traumatismo por Reperfusão , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/métodos , Animais , Modelos Animais de Doenças , Imageamento por Ressonância Magnética , Masculino , Nitritos/uso terapêutico , Ratos , Ratos Sprague-Dawley , Taxa de Sobrevida , Resultado do TratamentoRESUMO
Glioblastoma multiformes (GBMs) express increased aquaporin (AQP) 1 compared to normal brain. AQPs may contribute to edema, cell motility, and shuttling of H(2)O and H(+) from intracellular to extracellular space. We sought to gain insight into AQP1 function in GBM. In cultured 9L gliosarcoma cells, AQP1 expression was induced by dexamethasone, platelet-derived growth factor, NaCl, hypoxia, D-glucose (but not L-glucose), and fructose. Induction of AQP1 expression correlated with the level of glycolysis, maximized by increasing medium D-glucose or fructose and decreasing O(2), and was quantified by measuring lactate dehydrogenase (LDH) activity and medium lactate concentration. Upregulation of the protease cathepsin B was also observed in 9L cells cultured under glycolytic conditions. Immunohistochemical staining of human GBM specimens revealed increased coincident expression of AQP1, LDH, and cathepsin B in glioma cells associated with blood vessels at the tumor periphery. GBMs are known to exhibit aerobic glycolysis. Increased glucose metabolism at the tumor periphery may provide a scenario by which upregulation of AQP1, LDH, and cathepsin B contributes to acidification of the extracellular milieu and to invasive potential of glioma cells in perivascular space. The specific upregulation and metabolic consequences of increased AQP1 in gliomas may provide a therapeutic target, both as a cell surface marker and as a functional intervention.
Assuntos
Aquaporina 1/fisiologia , Neoplasias Encefálicas/patologia , Glioma/patologia , Gliossarcoma/patologia , Proteínas de Neoplasias/fisiologia , Aerobiose , Animais , Aquaporina 1/biossíntese , Aquaporina 1/genética , Neoplasias Encefálicas/metabolismo , Catepsina B/biossíntese , Catepsina B/genética , Hipóxia Celular , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Meios de Cultura Livres de Soro/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioma/metabolismo , Gliossarcoma/metabolismo , Glicólise , Hexoses/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular/química , L-Lactato Desidrogenase/biossíntese , L-Lactato Desidrogenase/genética , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Ratos , Elementos de RespostaRESUMO
Overexpression of vascular endothelial growth factor (VEGF) is associated with several central nervous system (CNS) diseases and abnormalities, and is often postulated as a causative factor and promising therapeutic target in these settings. The authors' goal was to reassess the contribution of VEGF to the biology and pathology of the CNS. The authors review the literature relating to the following aspects of VEGF: 1) the biology of VEGF in normal brain; 2) the involvement of VEGF in CNS disorders other than tumors (traumatic and ischemic injuries arteriovenous malformations, inflammation); and 3) the role of VEGF in brain tumor biology (gliomas and the associated vasogenic edema, and hemangioblastomas). The authors conclude the following: first, that VEGF overexpression contributes to the phenotype associated with many CNS disorders, but VEGF is a reactive rather than a causative factor in many cases; and second, that use of VEGF as a therapeutic agent or target is complicated by the effects of VEGF not only on the cerebral vasculature, but also on astrocytes, neurons, and inflammatory cells. In many cases, therapeutic interventions targeting the VEGF/VEGF receptor axis are likely to be ineffective or even detrimental. Clinical manipulation of VEGF levels in the CNS must be approached with caution.
Assuntos
Encefalopatias/patologia , Encefalopatias/fisiopatologia , Fator A de Crescimento do Endotélio Vascular/fisiologia , Animais , HumanosRESUMO
Malignant brain tumors exhibit distinct metabolic characteristics. Despite high levels of lactate, the intracellular pH of brain tumors is more alkaline than normal brain. Additionally, with increasing malignancy, brain tumors display intratumoral hypoxia. Carbonic anhydrase (CA) IX and XII are transmembrane isoenzymes that are induced by tissue hypoxia. They participate in regulation of pH homeostasis by catalyzing the reversible hydration of carbon dioxide. The aim of our study was to investigate whether brain tumors of different histology and grade of malignancy express elevated levels of CA IX and XII as compared to normal brain. We analyzed 120 tissue specimens from brain tumors (primary and metastatic) and normal brain for CA IX and XII expression by immunohistochemistry, Western blot, and in situ hybridization. Whereas normal brain tissue showed minimal levels of CA IX and XII expression, expression in tumors was found to be upregulated with increased level of malignancy. Hemangioblastomas, from patients with von Hippel-Lindau disease, also displayed high levels of CA IX and XII expression. Comparison of CA IX and XII staining with HIF-1alpha staining revealed a similar microanatomical distribution, indicating hypoxia as a major, but not the only, induction factor. The extent of CA IX and XII staining correlated with cell proliferation, as indicated by Ki67 labeling. The results demonstrate that CA IX and XII are upregulated in intrinsic and metastatic brain tumors as compared to normal brain tissue. This may contribute to the management of tumor-specific acid load and provide a therapeutic target.
Assuntos
Neoplasias Encefálicas/enzimologia , Anidrases Carbônicas/biossíntese , Hemangioblastoma/etiologia , Western Blotting , Hemangioblastoma/enzimologia , Humanos , Imuno-Histoquímica , Hibridização In Situ , Doença de von Hippel-Lindau/complicaçõesRESUMO
Despite the common occurrence and frequent clinical effects of peritumoral cysts in the central nervous system (CNS), the mechanism underlying their development and evolution is not understood. Because they commonly produce peritumoral cysts and because serial magnetic resonance imaging (MRI) is obtained in von Hippel-Lindau disease patients, hemangioblastomas provide an opportunity to examine the pathophysiology of CNS peritumoral cyst formation. Serial MRI was correlated with the clinical findings in 16 von Hippel-Lindau disease patients with 22 CNS hemangioblastomas (11 spinal cord; 11 cerebellar) that were associated with the appearance and evolution of peritumoral cysts. Hemangioblastoma-associated cyst wall histomorphological analysis was performed on postmortem tissues from three von Hippel-Lindau disease patients (not in the clinical series). Comparative proteomic profiling was performed on peritumoral cyst fluid and serum. Vascular endothelial growth factor levels were determined in peritumoral cysts. MRI clearly showed peritumoral edema that developed and slowly and progressively evolved into enlarging hemangioblastoma-associated cysts in all tumors (mean follow-up, 130 +/- 38 months; mean +/- standard deviation). Postcontrast MRI demonstrated convective leakage of gadolinium into cysts. Mean time required for edema to evolve into a cyst was 36 +/- 23 months (range, 8-72 months). Thirteen (59%) hemangioblastoma-cysts became symptomatic (mean time to symptom formation after cyst development, 35 +/- 32 months; range, 3-102 months) and required resection. Protein profiles of cyst fluid and serum were similar. Mean cyst fluid vascular endothelial growth factor concentration was 1.5 ng/ml (range, 0-5.4 ng/ml). Histology of the cyst walls was consistent with reactive gliosis. CNS peritumoral cyst formation is initiated by increased tumor vascular permeability, increased interstitial pressure in the tumor, and plasma extravasation with convective distribution into the surrounding tissue. When the delivery of plasma from the tumor exceeds the capacity of the surrounding tissue to absorb the extravasated fluid, edema (with its associated increased interstitial pressure) and subsequent cyst formation occur.
Assuntos
Neoplasias Encefálicas/patologia , Cistos do Sistema Nervoso Central/patologia , Edema/patologia , Adulto , Autopsia/métodos , Neoplasias Encefálicas/sangue , Neoplasias Encefálicas/líquido cefalorraquidiano , Neoplasias Encefálicas/fisiopatologia , Cistos do Sistema Nervoso Central/sangue , Cistos do Sistema Nervoso Central/líquido cefalorraquidiano , Cistos do Sistema Nervoso Central/fisiopatologia , Edema/complicações , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular/sangue , Fator A de Crescimento do Endotélio Vascular/líquido cefalorraquidianoRESUMO
The active lesions in multiple sclerosis (MS) are characterized by blood-brain-barrier (BBB) breakdown, upregulation of adhesion molecules on capillary endothelial cells, and perivascular inflammation, suggesting that altered vessel permeability and activated endothelial cells are involved in the pathogenesis of the disease. Vascular endothelial growth factor (VEGF) mediates multiple aspects of blood vessel physiology, including regulation of growth, permeability, and inflammation. To investigate a possible relationship between VEGF expression and CNS autoimmune disease, we examined VEGF expression in MS plaques compared to normal white matter by immunohistochemistry and in situ hybridization. VEGF expression was consistently upregulated in both acute and chronic MS plaques. We also examined VEGF expression during the course of experimental allergic encephalomyelitis (EAE) in rats. VEGF-positive cells with astrocytic morphology increased in the spinal cord during the development of EAE and were found in association with inflammatory cells. Furthermore, intracerebral infusion of VEGF in animals previously immunized with myelin basic protein induced an inflammatory response in the brain, whereas infusion of vehicle, or infusion of VEGF in naive animals, did not. These results suggest that overexpression of VEGF may exacerbate the inflammatory response in autoimmune diseases of the CNS by inducing focal BBB breakdown and migration of inflammatory cells into the lesions.