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.

Long-term safety of MRI-guided administration of AAV2-GDNF and gadoteridol in the putamen of individuals with Parkinson's disease.

Direct putaminal infusion of adeno-associated virus vector (serotype 2) (AAV2) containing the human glial cell line-derived neurotrophic factor (GDNF) transgene was studied in a phase I clinical trial of participants with advanced Parkinson's disease (PD). Convection-enhanced delivery of AAV2-GDNF with a surrogate imaging tracer (gadoteridol) was used to track infusate distribution during real-time intraoperative magnetic resonance imaging (iMRI). Pre-, intra-, and serial postoperative (up to 5 years after infusion) MRI were analyzed in 13 participants with PD treated with bilateral putaminal co-infusions (52 infusions in total) of AAV2-GDNF and gadoteridol (infusion volume, 450 mL per putamen). Real-time iMRI confirmed infusion cannula placement, anatomic quantification of volumetric perfusion within the putamen, and direct visualization of off-target leakage or cannula reflux (which permitted corresponding infusion rate/cannula adjustments). Serial post-treatment MRI assessment (n = 13) demonstrated no evidence of cerebral parenchyma toxicity in the corresponding regions of AAV2-GDNF and gadoteridol co-infusion or surrounding regions over long-term follow-up. Direct confirmation of key intraoperative safety and efficacy parameters underscores the safety and tissue targeting value of real-time imaging with co-infused gadoteridol and putative therapeutic agents (i.e., AAV2-GDNF). This delivery-imaging platform enhances safety, permits delivery personalization, improves therapeutic distribution, and facilitates assessment of efficacy and dosing effect.

Trial of magnetic resonance-guided putaminal gene therapy for advanced Parkinson's disease.

OBJECTIVE: To investigate the safety and tolerability of convection-enhanced delivery of an adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor into the bilateral putamina of PD patients. METHODS: Thirteen adult patients with advanced PD underwent adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor and gadoteridol (surrogate MRI tracer) coinfusion (450 µL/hemisphere) at escalating doses: 9 × 1010 vg (n = 6); 3 × 1011 vg (n = 6); and 9 × 1011 vg (n = 1). Intraoperative MRI monitored infusion distribution. Patients underwent UPDRS assessment and [18 F]FDOPA-PET scanning preoperatively and 6 and 18 months postoperatively. RESULTS: Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor was tolerated without clinical or radiographic toxicity. Average putaminal coverage was 26%. UPDRS scores remained stable. Ten of thirteen and 12 of 13 patients had increased [18 F]FDOPA Kis at 6 and 18 months postinfusion (increase range: 5-274% and 8-130%; median, 36% and 54%), respectively. Ki differences between baseline and 6- and 18-month follow-up were statistically significant (P < 0.0002). CONCLUSION: Adeno-associated virus, serotype-2 vector carrying glial cell line-derived neurotrophic factor infusion was safe and well tolerated. Increased [18 F]FDOPA uptake suggests a neurotrophic effect on dopaminergic neurons. © 2019 International Parkinson and Movement Disorder Society.

Prospective, Longitudinal Study of Clinical Outcome and Morphometric Posterior Fossa Changes after Craniocervical Decompression for Symptomatic Chiari I Malformation.

BACKGROUND AND PURPOSE: The time course of changes in posterior fossa morphology, quality of life, and neurologic function of patients with Chiari I malformation after craniocervical decompression requires further elaboration. To better understand the pace of these changes, we longitudinally studied patients with Chiari I malformation, with or without syringomyelia, before and after the operation for up to 5 years. MATERIALS AND METHODS: Thirty-eight symptomatic adult patients (35 women, 3 men) diagnosed with Chiari I malformation only (n = 15) or Chiari I malformation and syringomyelia (n = 23) and without previous Chiari I malformation surgery were enrolled in a clinical study. Patients underwent outpatient study visits and MR imaging at 7 time points (ie, initial [before the operation], 3 months, 1 year, 2 years, 3 years, 4 years, and 5 years) during 5 years. The surgical procedure for all patients was suboccipital craniectomy, C1 laminectomy, and autologous duraplasty. RESULTS: Morphometric measurements demonstrated an enlargement of the CSF areas posterior to the cerebellar tonsils after the operation, which remained largely stable through the following years. There was a decrease in pain and improved quality of life after the operation, which remained steady during the following years. Reduction in pain and improved quality of life correlated with CSF area morphometrics. CONCLUSIONS: Most changes in MR imaging morphometrics and quality of life measures occurred within the first year after the operation. A 1-year follow-up period after Chiari I malformation surgery is usually sufficient for evaluating surgical efficacy and postoperative MR imaging changes.

Proteostasis Modulation in Germline Missense von Hippel Lindau Disease.

PURPOSE: Missense mutated von Hippel Lindau (VHL) protein (pVHL) maintains intrinsic function but undergoes proteasomal degradation and tumor initiation and/or progression in VHL disease. Vorinostat can rescue missense mutated pVHL and arrest tumor growth in preclinical models. We asked whether short-term oral vorinostat could rescue pVHL in central nervous system hemangioblastomas in patients with germline missense VHL. PATIENTS AND METHODS: We administered oral vorinostat to 7 subjects (ages 46.0 ± 14.5 years) and then removed symptomatic hemangioblastomas surgically (ClinicalTrials.gov identifier NCT02108002). RESULTS: Vorinostat was tolerated without serious adverse events by all patients. pVHL expression was elevated in neoplastic stromal cells compared with untreated hemangioblastomas from same patients. We found transcriptional suppression of downstream hypoxia-inducible factor (HIF) effectors. Mechanistically, vorinostat prevented Hsp90 recruitment to mutated pVHL in vitro. The effects of vorinostat on the Hsp90-pVHL interaction, pVHL rescue, and transcriptional repression of downstream HIF effectors was independent of the location of the missense mutation on the VHL locus. We confirmed a neoplastic stromal cell-specific effect in suppression of protumorigenic pathways with single-nucleus transcriptomic profiling. CONCLUSIONS: We found that oral vorinostat treatment in patients with germline missense VHL mutations has a potent biologic effect that warrants further clinical study. These results provide biologic evidence to support the use of proteostasis modulation for the treatment of syndromic solid tumors involving protein misfolding. Proteostasis modulation with vorinostat rescues missense mutated VHL protein. Further clinical trials are needed to demonstrate tumor growth arrest.

Multiple VHL-related hemangioblastomas and holocord syrinx: identifying the causative lesion. Illustrative case.

BACKGROUND: Brainstem and spinal cord hemangioblastomas are a common manifestation of von Hippel-Lindau (VHL) disease. Cysts and associated syringes are the most common cause of significant morbidity in these patients. Surgical treatment of symptomatic hemangioblastomas are often complicated by the presence of multiple potential lesions, leading to cyst and syrinx formation. OBSERVATIONS: The authors present a case of a patient with multiple VHL-related hemangioblastomas who presented with syringobulbia and holocord syrinx. Resection of two cyst wall hemangioblastomas and one cervical hemangioblastoma only transiently improved syringobulbia. Eventual resolution of syringobulbia and collapse of the holocord syrinx only occurred following removal of a large lower thoracic hemangioblastoma. LESSONS: Surgical management of hemangioblastomas and associated cysts in patients with VHL should only target lesions most likely contributing to neurological deficits as excess surgical intervention risks treatment-related morbidity. The authors illustrate how anatomical and pathophysiological considerations as well as patient symptoms are key to identifying target lesions for resection and developing deliberate treatment plans.

Retrobulbar Hemangioblastomas in von Hippel-Lindau Disease: Clinical Course and Management.

BACKGROUND: Retrobulbar hemangioblastomas involving the optic apparatus in patients with von Hippel-Lindau disease (VHL) are rare, with only 25 reported cases in the literature. OBJECTIVE: To analyze the natural history of retrobulbar hemangioblastomas in a large cohort of VHL patients in order to define presentation, progression, and management. METHODS: Clinical history and imaging of 250 patients with VHL in an ongoing natural history trial and 1774 patients in a neurosurgical protocol were reviewed. The clinical course, magnetic resonance images, treatment, and outcomes were reviewed for all included patients. RESULTS: A total of 18 patients with retrobulbar hemangioblastoma on surveillance magnetic resonance imaging met the inclusion criteria for this study. Of the 17 for whom clinical information was available, 10 patients presented with symptoms related to the hemangioblastoma, and 7 were asymptomatic. The mean tumor volume was larger for symptomatic (810.6 ± 545.5 mm3) compared to asymptomatic patients (307.6 ± 245.5 mm3; P < .05). A total of 5 of the symptomatic patients were treated surgically and all experienced improvement in their symptoms. All 3 symptomatic patients that did not undergo intervention had continued symptom progression. Long-term serial imaging on asymptomatic patients showed that these tumors can remain radiographically stable and asymptomatic for extended periods of time (101.43 ± 71 mo). CONCLUSION: This study suggests that retrobulbar hemangioblastomas may remain stable and clinically asymptomatic for long durations. Recent growth and larger tumor volume were associated with symptom occurrence. Surgical treatment of symptomatic retrobulbar hemangioblastomas can be safe and may reverse the associated symptoms.

A Prospective Evaluation of Swallowing and Speech in Patients with Neurofibromatosis Type 2.

Objective Neurofibromatosis type 2 (NF2) patients report that swallowing and speech problems significantly affect their quality of life, but the etiology of these phenomena is poorly understood. Swallowing and speech deficits may arise due to the neuropathy of involved nerves, due to posterior fossa tumor growth, or as iatrogenic effects from neurosurgical procedures to remove these tumors. This study aims to identify the natural history of swallowing and speech deficits in an NF2 cohort and to characterize the factors that may lead to those deficits. Methods Subjects ( n = 168) were enrolled in a prospective, longitudinal study of NF2 with yearly imaging and clinical exams. The patients completed a self-reported questionnaire that included responses regarding subjective swallowing and speech dysfunction. A formal speech-language pathology evaluation and modified barium swallow (MBS) study (reported as American Speech-Language Hearing Association [ASHA] swallowing independency score from 1 through 7) was obtained when a speech/swallowing deficit was reported on the questionnaire. Results Of the 168 enrolled subjects, 55 (33%, median age = 31 years) reported subjective speech and/or swallowing deficits. These patients underwent one ( n = 37) or multiple ( n = 18) MBS studies during 44.8 ± 10.4 months follow-up. During MBS, a majority demonstrated near-normal swallowing (ASHA score >6, 82%), and no evidence of aspiration (aspiration/laryngeal penetration score = 1, 96%). Prior to initial MBS consultation, 38 (69%) patients had undergone relevant neurosurgical procedures. In those with recent (<1 week) posterior fossa surgery ( n = 12), 2 (17%) patients had severe dysphagia and high aspiration risk on postoperative MBS. Both of these patients recovered to functionally independent swallowing status. Unilateral ( n = 10) or bilateral ( n = 6) tongue deficits unrelated to previous history suggestive of hypoglossal nerve injury were detected on clinical examination. There was a correlation between the presence of dysarthria and tongue deficits and tumors associated with the hypoglossal canal noted on imaging. Conclusion A large proportion of patients with NF2 report speech and swallow deficits that are not evident on objective measurements. We also found hypoglossal neuropathy unrelated to prior surgical interventions. Our findings suggest that swallowing and speech problems in NF2 are associated with lower cranial nerve neuropathy, some due to compressive effects of posterior fossa tumors. Adaptation over the course of the disease allows for the compensation of these deficits and subsequent normal findings on objective testing.

Safe marginal resection of atypical neurofibromas in neurofibromatosis type 1.

OBJECTIVE: Patients with neurofibromatosis type 1 (NF1) are predisposed to visceral neurofibromas, some of which can progress to premalignant atypical neurofibromas (ANFs) and malignant peripheral nerve sheath tumors (MPNSTs). Though subtotal resection of ANF may prevent malignant transformation and thus deaths with no neural complications, local recurrences require reoperation. The aim of this study was to assess the surgical morbidity associated with marginal resection of targeted ANF nodules identified via preoperative serial volumetric MRI and 18F-FDG-PET imaging. METHODS: The authors analyzed clinical outcomes of 16 NF resections of 21 tumors in 11 NF1 patients treated at the NIH Clinical Center between 2008 and 2018. Preoperative volumetric growth rates and 18F-FDG-PET SUVMax (maximum standardized uptake value within the tumor) of the target lesions and any electromyographic or nerve conduction velocity abnormalities of the parent nerves were measured and assessed in tandem with postoperative complications, histopathological classification of the resected tumors, and surgical margins through Dunnett's multiple comparisons test and t-test. The surgical approach for safe marginal resection of ANF was also described. RESULTS: Eleven consecutive NF1 patients (4 male, 7 female; median age 18.5 years) underwent 16 surgical procedures for marginal resections of 21 tumors. Preoperatively, 13 of the 14 (93%) sets of serial MRI studies and 10 of the 11 (91%) 18F-FDG-PET scans showed rapid growth (≥ 20% increase in volume per year) and avidity (SUVMax ≥ 3.5) of the identified tumor, respectively (median tumor size 48.7 cm3; median growth rate 92% per year; median SUVMax 6.45). Most surgeries (n = 14, 88%) resulted in no persistent postoperative parent nerve-related complications, and to date, none of the resected tumors have recurred. The median length of postoperative follow-up has been 2.45 years (range 0.00-10.39 years). Histopathological analysis confirmed significantly greater SUVMax among the ANFs (6.51 ± 0.83, p = 0.0042) and low-grade MPNSTs (13.8, p = 0.0001) than in benign neurofibromas (1.9). CONCLUSIONS: This report evaluates the utility of serial imaging (MRI and 18F-FDG-PET SUVMax) to successfully detect ANF and demonstrates that safe, fascicle-sparing gross-total, extracapsular resection of ANF is possible with the use of intraoperative nerve stimulation and microdissection of nerve fascicles.