Persistent GDNF Expression 45 Months after Putaminal Infusion of AAV2-GDNF in a Patient with Parkinson's Disease.

OBJECTIVE: Gene therapy by convection-enhanced delivery of type 2 adeno-associated virus-glial cell derived neurotrophic factor (AAV2-GDNF) to the bilateral putamina seeks to increase GDNF gene expression and treat Parkinson's disease (PD). METHODS: A 63-year-old man with advanced PD received AAV2-GDNF in a clinical trial. He died from pneumonia after anterior cervical discectomy and fusion 45 months later. An autopsy included brain examination for GDNF transgene expression. Putaminal catecholamine concentrations were compared to in vivo 18F-Fluorodopa (18F-FDOPA) positron emission tomography (PET) scanning results before and 18 months after AAV2-GDNF infusion. RESULTS: Parkinsonian progression stabilized clinically. Postmortem neuropathology confirmed PD. Bilateral putaminal regions previously infused with AAV2-GDNF expressed the GDNF gene. Total putaminal dopamine was 1% of control, confirming the striatal dopaminergic deficiency suggested by baseline 18F-DOPA-PET scanning. Putaminal regions responded as expected to AAV2-GDNF. CONCLUSION: After AAV2-GDNF infusion, infused putaminal regions showed increased GDNF gene expression, tyrosine hydroxylase immunoreactive sprouting, catechol levels, and 18F-FDOPA-PET signal, suggesting the regenerative potential of AAV2-GDNF in PD. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Pituitary adenomas evade apoptosis via noxa deregulation in Cushing's disease.

Sporadic pituitary adenomas occur in over 10% of the population. Hormone-secreting adenomas, including those causing Cushing's disease (CD), cause severe morbidity and early mortality. Mechanistic studies of CD are hindered by a lack of in vitro models and control normal human pituitary glands. Here, we surgically annotate adenomas and adjacent normal glands in 25 of 34 patients. Using single-cell RNA sequencing (RNA-seq) analysis of 27594 cells, we identify CD adenoma transcriptomic signatures compared with adjacent normal cells, with validation by bulk RNA-seq, DNA methylation, qRT-PCR, and immunohistochemistry. CD adenoma cells include a subpopulation of proliferating, terminally differentiated corticotrophs. In CD adenomas, we find recurrent promoter hypomethylation and transcriptional upregulation of PMAIP1 (encoding pro-apoptotic BH3-only bcl-2 protein noxa) but paradoxical noxa downregulation. Using primary CD adenoma cell cultures and a corticotroph-enriched mouse cell line, we find that selective proteasomal inhibition with bortezomib stabilizes noxa and induces apoptosis, indicating its utility as an anti-tumor agent.

Transcriptomic analysis of human sensory neurons in painful diabetic neuropathy reveals inflammation and neuronal loss.

Pathological sensations caused by peripheral painful neuropathy occurring in Type 2 diabetes mellitus (T2DM) are often described as 'sharp' and 'burning' and are commonly spontaneous in origin. Proposed etiologies implicate dysfunction of nociceptive sensory neurons in dorsal root ganglia (DRG) induced by generation of reactive oxygen species, microvascular defects, and ongoing axonal degeneration and regeneration. To investigate the molecular mechanisms contributing to diabetic pain, DRGs were acquired postmortem from patients who had been experiencing painful diabetic peripheral neuropathy (DPN) and subjected to transcriptome analyses to identify genes contributing to pathological processes and neuropathic pain. DPN occurs in distal extremities resulting in the characteristic "glove and stocking" pattern. Accordingly, the L4 and L5 DRGs, which contain the perikarya of primary afferent neurons innervating the foot, were analyzed from five DPN patients and compared with seven controls. Transcriptome analyses identified 844 differentially expressed genes. We observed increases in levels of inflammation-associated transcripts from macrophages in DPN patients that may contribute to pain hypersensitivity and, conversely, there were frequent decreases in neuronally-related genes. The elevated inflammatory gene profile and the accompanying downregulation of multiple neuronal genes provide new insights into intraganglionic pathology and mechanisms causing neuropathic pain in DPN patients with T2DM.

FGFR1-TACC1 fusion associated with malignant transformation in a primary spinal cord glioma: a case report.

Molecular mechanisms of malignant transformation in spinal cord gliomas are not well-understood. Our objective was to investigate genetic causes of malignant transformation in a primary spinal cord glioma. A 32-year-old female patient presented with bilateral lower extremity weakness and was diagnosed with a primary spinal cord glioma from T9 to T12, with a syrinx extending from the craniocervical junction to the conus. She underwent resection in 2006. Pathology showed an abundance of Rosenthal fibers, calcification and degenerative features consistent with a low-grade pilocytic astrocytoma. She presented in 2020 with tumor recurrence and underwent re-resection. Whole exome sequencing, DNA methylation profiling and immunohistochemistry were performed on her initial and recurrent tumor samples. Immunohistochemical profiling of her recurrent tumor showed pleomorphic cells with extensive necrosis consistent with a high-grade glioma. DNA methylation profiling showed that the initial tumor clustered with pilocytic astrocytomas, whereas the recurrent lesion clustered with anaplastic astrocytomas, confirming malignant transformation. Whole-exome sequencing showed interim acquisition of a rare fibroblast growth factor receptor-transforming acidic coiled-coil (FGFR1-TACC1) gene fusion. We report an FGFR1-TACC1 fusion associated with malignant transformation in a primary spinal cord glioma. Our study adds to growing reports of FGFR-TACC fusions, which are amenable to receptor tyrosine kinase inhibition.

Pathological Features of Tumors of the Nervous System in Hereditary Cancer Predisposition Syndromes: A Review.

Hereditary cancer predisposition syndromes (HCS) become more recognizable as the knowledge about them expands, and genetic testing becomes more affordable. In this review, we discussed the known HCS that predispose to central and peripheral nervous system tumors. Different genetic phenomena were highlighted, and the important cellular biological alterations were summarized. Genetic mosaicism and germline mutations are features of HCS, and recently, they were described in normal population and as modifiers for the genetic landscape of sporadic tumors. Description of the tumors arising in these conditions was augmented by representative cases explaining the main pathological findings. Clinical spectrum of the syndromes and diagnostic criteria were tabled to outline their role in defining these disorders. Interestingly, precision medicine has found its way to help these groups of patients by offering targeted preventive measures. Understanding the signaling pathway alteration of mammalian target of rapamycin (mTOR) in tuberous sclerosis helped introducing mTOR inhibitors as a prophylactic treatment in these patients. More research to define the germline genetic alterations and resulting cellular signaling perturbations is needed for effective risk-reducing interventions beyond prophylactic surgeries.

Inhibiting protein phosphatase 2A increases the antitumor effect of protein arginine methyltransferase 5 inhibition in models of glioblastoma.

BACKGROUND: Despite multi-model therapy of maximal surgical resection, radiation, chemotherapy, and tumor-treating fields, the median survival of glioblastoma (GBM) patients is less than 15 months. Protein arginine methyltransferase 5 (PRMT5) catalyzes the symmetric dimethylation of arginine residues and is overexpressed in GBM. Inhibition of PRMT5 causes senescence in stem-like GBM tumor cells. LB100, a first-in-class small molecular inhibitor of protein phosphatase 2A (PP2A), can sensitize therapy-resistant tumor cells. Here, we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition. METHODS: Patient-derived primary GBM neurospheres (GBMNS), transfected with PRMT5 target-specific siRNA, were treated with LB100 and subjected to in vitro assays including PP2A activity and western blot. The intracranial mouse xenograft model was used to test the in vivo antitumor efficacy of combination treatment. RESULTS: We found that PRMT5 depletion increased PP2A activity in GBMNS. LB100 treatment significantly reduced the viability of PRMT5-depleted GBMNS compared to PRMT5-intact GBMNS. LB100 enhanced G1 cell cycle arrest induced by PRMT5 depletion. Combination therapy also increased the expression of phospho-MLKL. Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100, indicating that necroptosis caused the enhanced cytotoxicity of combination therapy. In the in vivo mouse tumor xenograft model, LB100 treatment combined with transient depletion of PRMT5 significantly decreased tumor size and prolonged survival, while LB100 treatment alone had no survival benefit. CONCLUSION: Overall, combined PRMT5 and PP2A inhibition had significantly greater antitumor effects than PRMT5 inhibition alone.

HHV-6 and hippocampal volume in patients with mesial temporal sclerosis.

OBJECTIVE: To study the effects of human herpes virus 6 (HHV-6) on the hippocampal volume in patients with mesial temporal sclerosis (MTS). BACKGROUND: HHV-6 may play an etiologic role in MTS. Previous studies found a possible association with febrile status epilepticus. Several investigators have reported a higher prevalence of HHV-6 in MTS resections compared to other epilepsy etiologies. DESIGN/METHODS: We used FreeSurfer to segment cortical structures and obtain whole hippocampal and subfield volumes in 41 patients with intractable epilepsy. In addition, an investigator blinded to other data traced hippocampi manually on each slice. The main study outcome measure was the asymmetry index (AI) between hippocampal volumes ipsilateral and contralateral to seizure foci compared between HHV-6 positive and negative patients. Viral DNA was isolated from fresh brain tissue obtained at temporal lobectomy. For 25 patients, viral detection was performed using quantitative real-time PCR specific for HHV-6A and HHV-6B. For 16 patients, viral DNA detection was performed using digital droplet PCR specific for HHV-6A and HHV-6B. RESULTS: Twenty-two patients were positive (14 of 25 tested with real-time PCR, and 8 of 16 with digital droplet PCR), and 19 negatives for HHV-6. HHV-6 negative patients had significantly greater AI and lower total hippocampal volume ipsilateral to seizure foci than HHV-6 positive patients. Epilepsy duration and age of onset did not affect results. INTERPRETATION: Our data suggest multiple potential etiologies for MTS. HHV-6 may have a less severe effect on the hippocampus than other etiologies.

Pathological Features of Brain Metastases.

Metastases are the most common intracranial tumors in adults. Lung cancer, melanoma, renal cell carcinoma, and breast cancer are the most common primary tumors that metastasize to the brain. Improved detection of small metastases by MRI, and improved systemic therapy for primary tumors, resulted in increased incidence of brain metastasis. Advances in neuroanesthesia and neurosurgery have significantly improved the safety of surgical resection of brain metastases. Surgical approach and active management have become applicable for many patients. Subsequently, brain metastases diagnosis no longer equals palliative treatment. Moreover, the demand for diagnosing brain masses has increased with its associated challenges.

Comparative clinical and genomic analysis of neurofibromatosis type 2-associated cranial and spinal meningiomas.

Neurofibromatosis type 2 (NF2) is an autosomal dominant Mendelian tumor predisposition disorder caused by germline pathogenic variants in the tumor suppressor NF2. Meningiomas are the second most common neoplasm in NF2, often occurring in multiple intracranial and spinal locations within the same patient. In this prospective longitudinal study, we assessed volumes and growth rates of ten spinal and ten cranial benign meningiomas in seven NF2 patients that concluded with surgical resection and performed whole-exome sequencing and copy-number variant (CNV) analysis of the tumors. Our comparison of the volume and the growth rate of NF2-associated spinal and cranial meningiomas point to the differences in timing of tumor initiation and/or to the differences in tumor progression (e.g., non-linear, saltatory growth) at these two anatomical locations. Genomic investigation of these tumors revealed that somatic inactivation of NF2 is the principal and perhaps the only driver of tumor initiation; and that tumor progression likely occurs via accumulation of CNVs, rather than point mutations. Results of this study contribute to a better understanding of NF2-associated meningiomas clinical behavior and their genetic underpinnings.

Traumatic microbleeds suggest vascular injury and predict disability in traumatic brain injury.

Traumatic microbleeds are small foci of hypointensity seen on T2*-weighted MRI in patients following head trauma that have previously been considered a marker of axonal injury. The linear appearance and location of some traumatic microbleeds suggests a vascular origin. The aims of this study were to: (i) identify and characterize traumatic microbleeds in patients with acute traumatic brain injury; (ii) determine whether appearance of traumatic microbleeds predict clinical outcome; and (iii) describe the pathology underlying traumatic microbleeds in an index patient. Patients presenting to the emergency department following acute head trauma who received a head CT were enrolled within 48 h of injury and received a research MRI. Disability was defined using Glasgow Outcome Scale-Extended ≤6 at follow-up. All magnetic resonance images were interpreted prospectively and were used for subsequent analysis of traumatic microbleeds. Lesions on T2* MRI were stratified based on 'linear' streak-like or 'punctate' petechial-appearing traumatic microbleeds. The brain of an enrolled subject imaged acutely was procured following death for evaluation of traumatic microbleeds using MRI targeted pathology methods. Of the 439 patients enrolled over 78 months, 31% (134/439) had evidence of punctate and/or linear traumatic microbleeds on MRI. Severity of injury, mechanism of injury, and CT findings were associated with traumatic microbleeds on MRI. The presence of traumatic microbleeds was an independent predictor of disability (P < 0.05; odds ratio = 2.5). No differences were found between patients with punctate versus linear appearing microbleeds. Post-mortem imaging and histology revealed traumatic microbleed co-localization with iron-laden macrophages, predominately seen in perivascular space. Evidence of axonal injury was not observed in co-localized histopathological sections. Traumatic microbleeds were prevalent in the population studied and predictive of worse outcome. The source of traumatic microbleed signal on MRI appeared to be iron-laden macrophages in the perivascular space tracking a network of injured vessels. While axonal injury in association with traumatic microbleeds cannot be excluded, recognizing traumatic microbleeds as a form of traumatic vascular injury may aid in identifying patients who could benefit from new therapies targeting the injured vasculature and secondary injury to parenchyma.

CRH stimulation improves 18F-FDG-PET detection of pituitary adenomas in Cushing's disease.

OBJECTIVE: In MRI-negative cases Cushing's disease (CD), surgeons perform a more extensive exploration of the pituitary gland, with fewer instances of hormonal remission. 18F-fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) has a limited role in detecting adenomas that cause CD (corticotropinomas). Our previous work demonstrated corticotropin-releasing hormone (CRH) stimulation leads to delayed, selective glucose uptake in corticotropinomas. Here, we prospectively evaluated the utility of CRH stimulation in improving 18F-FDG-PET detection of adenomas in CD. METHODS: Subjects with a likely diagnosis of CD (n = 27, 20 females) each underwent two 18F-FDG-PET studies [without and with ovine-CRH (oCRH) stimulation] on a high-resolution PET platform. Standardized-uptake-values (SUV) in the sella were calculated. Two blinded neuroradiologists independently read 18F-FDG-PET images qualitatively. Adenomas were histopathologically confirmed, analyzed for mutations in the USP8 gene and for glycolytic pathway proteins. RESULTS: The mean-SUV of adenomas was significantly increased from baseline (3.6 ± 1.5) with oCRH administration (3.9 ± 1.7; one-tailed p = 0.003). Neuroradiologists agreed that adenomas were visible on 21 scans, not visible on 26 scans (disagreed about 7, kappa = 0.7). oCRH-stimulation led to the detection of additional adenomas (n = 6) not visible on baseline-PET study. Of the MRI-negative adenomas (n = 5), two were detected on PET imaging (one only after oCRH-stimulation). USP8 mutations or glycolytic pathway proteins were not associated with SUV in corticotropinomas. CONCLUSIONS: The results of the current study suggest that oCRH-stimulation may lead to increased 18F-FDG uptake, and increased rate of detection of corticotropinomas in CD. These results also suggest that some MRI invisible adenomas may be detectable by oCRH-stimulated FDG-PET imaging. CLINICAL TRIAL INFORMATION: 18F-FDG-PET imaging with and without CRH stimulation was performed under the clinical trial NIH ID 12-N-0007 (clinicaltrials.gov identifier NCT01459237). The transsphenoidal surgeries and post-operative care was performed under the clinical trial NIH ID 03-N-0164 (clinicaltrials.gov identifier NCT00060541).

Convection-Enhanced Delivery of Muscimol Into the Bilateral Subthalamic Nuclei of Nonhuman Primates.

BACKGROUND: Muscimol is a gamma-aminobutyric acid receptor agonist that selectively and temporarily inhibits neurons. Local bolus injection of muscimol has been used experimentally to inhibit neuronal populations within discrete anatomical structures and discern their physiological function. OBJECTIVE: To determine the safety and behavioral effects of convection-enhanced delivery of muscimol into the bilateral subthalamic nuclei (STN) of nonhuman primate rhesus macaques (NHPs). METHODS: Six awake NHPs underwent co-infusion of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), a surrogate magnetic resonance imaging (MRI) tracer, with increasing concentrations of muscimol for behavioral and histological assessment. Three other NHPs were co-infused with Gd-DTPA and 3H-muscimol into the STN to determine muscimol distribution by MRI and autoradiography. Two NHPs underwent microcatheter implantation without muscimol infusion for control comparison. RESULTS: MRI revealed selective and complete perfusion of the bilateral STN in animals infused with Gd-DTPA and muscimol. No abnormal movements occurred at 0.125 mM. Muscimol doses between 0.25 and 4.4 mM resulted in transient, dose-dependent hyperkinesia. Muscimol (8.8 mM) resulted in severe bilateral dyskinesias, ballistic movements, and sedation. An 88.8 mM dose produced unresponsiveness in 1 animal. Infusion-related pathological abnormities or toxicity was not present on histological examination. MRI distribution of co-infused Gd-DTPA was similar to autoradiographic distribution of 3H-muscimol (Vd; R = 0.94). Mean Vd of infused animals was 37.9 mm3 ± 11.7 mm3 and mean Vd: Vi 7.6 ± 2.3. CONCLUSION: Bilateral convection-enhanced delivery of muscimol into the primate STN resulted in dose-related hyperkinetic movements that resolved after stopping the infusion. Muscimol was not toxic to brain tissue. Gd-DTPA accurately tracked muscimol distribution.

Cells isolated from residual intracranial tumors after treatment express iPSC genes and possess neural lineage differentiation plasticity.

BACKGROUND: The goal of this study is to identify and characterize treatment resistant tumor initiating cells (TRTICs) using orthotopic xenografts. METHODS: TRTICs were enriched from GBM cell lines using mouse xenografts treated with fractionated doses of radiation and temozolomide. TRTICs were characterized by neurosphere clonogenicity and self-renewal, serial xenotransplantation, differentiation potential, and mRNA & miRNA transcriptomic profiling. We use an unbiased approach to identify antigens encoding TRTIC and glioma stem cells (GSC) populations. Co-culture experiments of TRTIC and differentiated cells were conducted to evaluate the reliance of TRTIC differentiation on the secretome of differentiated cells. FINDINGS: TRTICs acquire stem-like gene expression signatures and increased side population staining resulting from the activation of multi-drug resistance genes. Genetic and functional characterization of TRTICs shows a striking resemblance with GSCs. TRTICs can differentiate towards specific progeny in the neural stem cell lineage. TRTIC-derived tumors display all the histological hallmarks of glioblastoma (GBM) and exhibit a miRNA-transcript and mRNA-transcriptomic profile associated with aggressiveness. We report that CD24+/CD44+ antigens are expressed in TRTICs and patient-derived GSCs. Double positive CD24+/CD44+ exhibit treatment resistance and enhanced tumorigenicity. Interestingly, co-culture experiments with TRTICs and differentiated cells indicated that the regulation of TRTIC differentiation could rely on the secretome in the tumor niche. INTERPRETATION: Radiation and temozolomide treatment enriches a population of cells that have increased iPSC gene expression. As few as 500 cells produced aggressive intracranial tumors resembling patient GBM. CD24+/CD44+ antigens are increased in TRTICs and patient-derived GSCs. The enrichment for TRTICs may result in part from the secretome of differentiated cells. FUND: NIH/NCI 1RC2CA148190, 1R01CA108633, 1R01CA188228, and The Ohio State University Comprehensive Cancer Center.

Pedunculopontine Nucleus Cholinergic Deficiency in Cervical Dystonia.

BACKGROUND: The etiology of cervical dystonia is unknown. Cholinergic abnormalities have been identified in dystonia animal models and human imaging studies. Some animal models have cholinergic neuronal loss in the striatum and increased acetylcholinesterase activity in the pedunculopontine nucleus. OBJECTIVES: The objective of this study was to determine the presence of cholinergic abnormalities in the putamen and pedunculopontine nucleus in cervical dystonia human brain donors. METHODS: Formalin-fixed brain tissues were obtained from 8 cervical dystonia and 7 age-matched control brains (controls). Pedunculopontine nucleus was available in only 6 cervical dystonia and 5 controls. Neurodegeneration was evaluated pathologically in the putamen, pedunculopontine nucleus, and other regions. Cholinergic neurons were detected using choline acetyltransferase immunohistochemistry in the putamen and pedunculopontine nucleus. Putaminal cholinergic neurons were quantified. A total of 6 cervical dystonia patients and 6 age-matched healthy controls underwent diffusion tensor imaging to determine if there were white matter microstructural abnormalities around the pedunculopontine nucleus. RESULTS: Decreased or absent choline acetyltransferase staining was identified in all 6 pedunculopontine nucleus samples in cervical dystonia. In contrast, strong choline acetyltransferase staining was present in 4 of 5 pedunculopontine nucleus controls. There were no differences in pedunculopontine nucleus diffusion tensor imaging between cervical dystonia and healthy controls. There was no difference in numbers of putaminal cholinergic neurons between cervical dystonia and controls. CONCLUSIONS: Our findings suggest that pedunculopontine nucleus choline acetyltransferase deficiency represents a functional cholinergic deficit in cervical dystonia. Structural lesions and confounding neurodegenerative processes were excluded by absence of neuronal loss, gliosis, diffusion tensor imaging abnormalities, and beta-amyloid, tau, and alpha-synuclein pathologies. © 2018 International Parkinson and Movement Disorder Society.

Senataxin Mutation Reveals How R-Loops Promote Transcription by Blocking DNA Methylation at Gene Promoters.

R-loops are three-stranded nucleic acid structures found abundantly and yet often viewed as by-products of transcription. Studying cells from patients with a motor neuron disease (amyotrophic lateral sclerosis 4 [ALS4]) caused by a mutation in senataxin, we uncovered how R-loops promote transcription. In ALS4 patients, the senataxin mutation depletes R-loops with a consequent effect on gene expression. With fewer R-loops in ALS4 cells, the expression of BAMBI, a negative regulator of transforming growth factor ß (TGF-ß), is reduced; that then leads to the activation of the TGF-ß pathway. We uncovered that genome-wide R-loops influence promoter methylation of over 1,200 human genes. DNA methyl-transferase 1 favors binding to double-stranded DNA over R-loops. Thus, in forming R-loops, nascent RNA blocks DNA methylation and promotes further transcription. Hence, our results show that nucleic acid structures, in addition to sequences, influence the binding and activity of regulatory proteins.

Corticotropin releasing hormone can selectively stimulate glucose uptake in corticotropinoma via glucose transporter 1.

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.

Potential utility of FLAIR in MRI-negative Cushing's disease.

OBJECTIVE Accurate presurgical localization of microadenomas in Cushing's disease (CD) leads to improved remission rates and decreased adverse events. Volumetric gradient recalled echo (3D-GRE) MRI detects pituitary microadenomas in CD in up to 50%-80% cases as a focus of hypointensity due to delayed contrast wash-in. The authors have previously reported that postcontrast FLAIR imaging may be useful in detecting otherwise MRI-negative pituitary microadenomas as foci of hyperintensity. This reflects theoretically complementary imaging of microadenomas due to delayed contrast washout. The authors report on the diagnostic accuracy and clinical utility of FLAIR imaging in the detection of microadenomas in patients with CD. METHODS The authors prospectively analyzed imaging findings in 23 patients (24 tumors) with biochemically proven CD who underwent transsphenoidal surgery for CD. Preoperatively, the patients underwent pituitary MRI with postcontrast FLAIR and postcontrast 3D-GRE sequences. RESULTS Postcontrast FLAIR hyperintensity was detected in macroadenomas, and in 3D-GRE-positive or -negative microadenomas. Overall, 3D-GRE was superior in detecting surgically and histopathologically confirmed, location-concordant microadenomas. Of 24 pituitary adenomas, 18 (75%; sensitivity 82%, positive predictive value 95%) were found on 3D-GRE, and 13 (50% [1 was false positive]; sensitivity 55%, positive predictive value 92%) were correctly identified on FLAIR. The stand-alone specificity of 3D-GRE and FLAIR was similar (50%). These results confirm the superiority of 3D-GRE as a stand-alone imaging modality. The authors then tested the utility of FLAIR as a complementary tool to 3D-GRE imaging. All 5 patients with negative 3D-GRE MRI displayed a distinct focus of FLAIR enhancement. Four of those 5 cases (80%) had location-concordant positive histopathological results and achieved postsurgical biochemical remission. The remaining patient was not cured, because resection did not include the region of FLAIR hyperintensity. CONCLUSIONS This study suggests that delayed microadenoma contrast washout may be detected as FLAIR hyperintensity in otherwise MRI-negative CD cases. The authors propose adding postcontrast FLAIR sequences to complement 3D-GRE for surgical planning in patients with CD. Clinical trial registration no.: NIH protocol 03-N-0164, NCT00060541 (clinicaltrials.gov).

Discovery of Aquaporin-1 and Aquaporin-4 Expression in an Intramedullary Spinal Cord Ependymal Cyst: Case Report.

BACKGROUND: Intramedullary ependymal cysts of the spinal cord are rare, benign, fluid-filled cysts usually situated along the ventral surface of the spinal cord. Only 32 cases have been reported since they were first described. Thus, owing to the rarity at which these cysts are encountered, their management and pathogenesis remain controversial. Whereas some investigators have advocated for cystosubarachnoid shunt placement for symptomatic ependymal cysts, others have argued for complete cyst resection or simple fenestration. Here we report the case of a 56-year-old female with a T11-T12 ependymal cyst that was successfully managed with cyst fenestration. We further investigated a potential pathological mechanism of cyst formation by performing immunohistochemistry to detect aquaporin expression in the cyst lining. CASE DESCRIPTION: A 56-year-old female was found to harbor an enlarging cystic lesion of the conus that was discovered on workup of progressive paraparesis and urinary incontinence. She had lower extremity weakness and progressive myelopathy. Thoracic laminectomy with cyst fenestration arrested her neurologic deterioration. Pathological analysis revealed an intramedullary ependymal cyst. Immunohistochemistry was subsequently performed for expression of aquaporin-1 and aquaporin-4. There was dense staining of the underlying neuropil with concurrent membranous staining pattern of the cyst lining. CONCLUSIONS: Intramedullary ependymal cysts are rare, cystic lesions of the spinal cord. Early cyst fenestration decompresses the cyst and prevents neurologic deterioration. Here we report for the first time that aquaporins are expressed in the cyst wall, which is consistent with a passive, osmotic pathogenic mechanism of cyst formation.