Non-Invasive Vagus Nerve Stimulation Improves Brain Lesion Volume and Neurobehavioral Outcomes in a Rat Model of Traumatic Brain Injury.

Abstract Traumatic brain injury (TBI) continues to be a major cause of death and disability worldwide. This study assessed the effectiveness of non-invasive vagus nerve stimulation (nVNS) in reducing brain lesion volume and improving neurobehavioral performance in a rat model of TBI. Animals were randomized into three experimental groups: (1) TBI with sham stimulation treatment (Control), (2) TBI treated with five lower doses (2-min) nVNS, and (3) TBI treated with five higher doses (2 × 2-min) nVNS. We used the gammaCore nVNS device to deliver stimulations. Magnetic resonance imaging studies were performed 1 and 7 days post-injury to confirm lesion volume. We observed smaller brain lesion volume in the lower dose nVNS group compared with the control group on days 1 and 7. The lesion volume for the higher dose nVNS group was significantly smaller than either the lower dose nVNS or the control groups on days 1 and 7 post-injury. The apparent diffusion coefficient differences between the ipsilateral and contralateral hemispheres on day 1 were significantly smaller for the higher dose (2 × 2 min) nVNS group than for the control group. Voxel-based morphometry analysis revealed an increase in the ipsilateral cortical volume in the control group caused by tissue deformation and swelling. On day 1, these abnormal volume changes were 13% and 55% smaller in the lower dose and higher dose nVNS groups, respectively, compared with the control group. By day 7, nVNS dampened cortical volume loss by 35% and 89% in the lower dose and higher dose nVNS groups, respectively, compared with the control group. Rotarod, beam walking, and anxiety performances were significantly improved in the higher-dose nVNS group on day 1 compared with the control group. The anxiety indices were also improved on day 7 post-injury compared with the control and the lower-dose nVNS groups. In conclusion, the higher dose nVNS (five 2 × 2-min stimulations) reduced brain lesion volume to a level that further refined the role of nVNS therapy for the acute treatment of TBI. Should nVNS prove effective in additional pre-clinical TBI models and later in clinical settings, it would have an enormous impact on the clinical practice of TBI in both civilian and military settings, as it can easily be adopted into routine clinical practice.

Advanced frailty assessment tool predicts successful awake craniotomy in a 92-year-old patient: A case report.

Background: The awake craniotomy (AC) procedure allows for safe and maximal resection of brain tumors from highly eloquent regions. However, geriatric patients are often viewed as poor candidates for AC due to age and medical comorbidities. Frailty assessments gauge physiological reserve for surgery and are valuable tools for preoperative decision-making. Here, we present a novel case illustrating how frailty scoring enabled an elderly but otherwise healthy female to undergo successful AC for tumor resection. Case Description: A 92-year-old right-handed female with history of hypertension and basal cell skin cancer presented with a 1-month history of progressive aphasia and was found to have a ring-enhancing left frontoparietal mass abutting the rolandic cortex concerning for malignant neoplasm. Frailty scoring with the recalibrated risk analysis index (RAI-C) tool revealed a score of 30 (of 81) indicating low surgical risk. The patient and family were counseled appropriately that, despite advanced chronological age, a low frailty score predicts favorable surgical outcomes. The patient underwent left-sided AC for resection of tumor and experienced immediate improvement of speech intraoperatively. After surgery, the patient was neurologically intact and had an unremarkable postoperative course with significant improvements from preoperatively baseline at follow-up. Conclusion: To the best of our knowledge, this case represents the oldest patient to undergo successful AC for brain tumor resection. Nonfrail patients over 90 years of age with the proper indications may tolerate cranial surgery. Frailty scoring is a powerful tool for preoperative risk assessment in the geriatric neurosurgery population.

Cognitive Reserve and Mild Cognitive Impairment: Predictors and Rates of Reversion to Intact Cognition vs Progression to Dementia.

BACKGROUND AND OBJECTIVES: Little is known about the effect of education or other indicators of cognitive reserve on the rate of reversion from mild cognitive impairment (MCI) to normal cognition (NC) or the relative rate (RR) of reversion from MCI to NC vs progression from MCI to dementia. Our objectives were to (1) estimate transition rates from MCI to NC and dementia and (2) determine the effect of age, APOE, and indicators of cognitive reserve on the RR of reversion vs progression using multistate Markov modeling. METHODS: We estimated instantaneous transition rates between NC, MCI, and dementia after accounting for transition to death across up to 12 assessments in the Nun Study, a cohort study of religious sisters aged 75+ years. We estimated RRs of reversion vs progression for age, APOE, and potential cognitive reserve indicators: education, academic performance (high school grades), and written language skills (idea density, grammatical complexity). RESULTS: Of the 619 participants, 472 were assessed with MCI during the study period. Of these 472, 143 (30.3%) experienced at least one reverse transition to NC, and 120 of the 143 (83.9%) never developed dementia (mean follow-up = 8.6 years). In models adjusted for age group and APOE, higher levels of education more than doubled the RR ratio of reversion vs progression. Novel cognitive reserve indicators were significantly associated with a higher adjusted RR of reversion vs progression (higher vs lower levels for English grades: RR ratio = 1.83; idea density: RR ratio = 3.93; and grammatical complexity: RR ratio = 5.78). DISCUSSION: Knowledge of frequent reversion from MCI to NC may alleviate concerns of inevitable cognitive decline in those with MCI. Identification of characteristics predicting the rate of reversion from MCI to NC vs progression from MCI to dementia may guide population-level interventions targeting these characteristics to prevent or postpone MCI and dementia. Research on cognitive trajectories would benefit from incorporating predictors of reverse transitions and competing events, such as death, into statistical modeling. These results may inform the design and interpretation of MCI clinical trials, given that a substantial proportion of participants may experience improvement without intervention.

MicroRNA Analysis of Human Stroke Brain Tissue Resected during Decompressive Craniectomy/Stroke-Ectomy Surgery.

BACKGROUND: Signaling pathways mediated by microRNAs (miRNAs) have been identified as one of the mechanisms that regulate stroke progression and recovery. Recent investigations using stroke patient blood and cerebrospinal fluid (CSF) demonstrated disease-specific alterations in miRNA expression. In this study, for the first time, we investigated miRNA expression signatures in freshly removed human stroke brain tissue. METHODS: Human brain samples were obtained during craniectomy and brain tissue resection in severe stroke patients with life-threatening brain swelling. The tissue samples were subjected to histopathological and immunofluorescence microscopy evaluation, next generation miRNA sequencing (NGS), and bioinformatic analysis. RESULTS: miRNA NGS analysis detected 34 miRNAs with significantly aberrant expression in stroke tissue, as compared to non-stroke samples. Of these miRNAs, 19 were previously identified in stroke patient blood and CSF, while dysregulation of 15 miRNAs was newly detected in this study. miRNA direct target gene analysis and bioinformatics approach demonstrated a strong association of the identified miRNAs with stroke-related biological processes and signaling pathways. CONCLUSIONS: Dysregulated miRNAs detected in our study could be regarded as potential candidates for biomarkers and/or targets for therapeutic intervention. The results described herein further our understanding of the molecular basis of stroke and provide valuable information for the future functional studies in the experimental models of stroke.

Transfemoral Approach to Induce Transient Middle Cerebral Artery Occlusion in Rats: The Use of Commercially Available Endovascular Wires.

BACKGROUND: Animal models of stroke play a crucial role in determining the pathophysiology of stroke progression and assessment of any new therapeutic approaches. Transient middle cerebral artery occlusion (tMCAo) in rodent models are the most common site-specific type of ischemia because of their relevance to the clinical setting. Compared with the intraluminal filament technique for inducing tMCAo, the transfemoral approach using endovascular wires is relatively a new technique METHODS: Here we present the use of commercially available wires used for neuro-endovascular surgical procedures to induce tMCAo in rats via a transfemoral approach. We used male Wistar rats in four groups to assess the effect of occlusion time (1 vs. 2 hours) and the wire type (PT2 TM 0.014″ vs. TransendTM EX, 0.014″, Boston Scientific, MA, USA). Infarct volume, edema, neurological deficits, and pro-inflammatory/anti-inflammatory blood biomarkers were used as outcome measures. RESULTS: We observed a significant effect of the wire type on the infarct volume (p value = 0.0096) where infarcts were slightly larger in the PT2 wiregroups. However, the occlusion time had no significant effect on infarct volume, even though the interaction between wire-type * occlusion-time was significant (p value = 0.024). Also, the amount of edema and blood pro-inflammatory/anti-inflammatory biomarkers were not statistically different among the wire-type and occlusion-time groups. CONCLUSIONS: The choice of appropriate endovascular wire should probably be the focus of the study design instead of the occlusion time when planning an experiment. The transfemoral approach using endovascular wires for inducing tMCAo in rats provides a more consistent outcome with fewer complications compared with suture filament models.

A Congenital Case of Ependymoblastoma: A Rare and Aggressive Brain Tumor.

Congenital brain tumors are rare, representing <2% of all childhood brain tumors. Of these, ependymoblastoma is a profoundly aggressive embryonal brain tumor that is included in the diagnostic entity known as an embryonal tumor with multilayered rosettes. This report of a congenital ependymoblastoma diagnosed at birth aims to highlight how much remains unknown about embryonal tumor with multilayered rosettes and the devastating prognosis of this condition. Despite recent advancements made in identifying molecular targets for therapy, this tumor continues to have a high rate of recurrence with few successful treatment options, especially when diagnosed in the newborn period.

Sellar Region Atypical Teratoid/Rhabdoid Tumors in Adults: Clinicopathological Characterization of Five Cases and Review of the Literature.

Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant CNS neoplasms that typically occur in children <2 years of age. These are characterized by high-grade histologic features and mutations of the INI1/SMARCB1 gene readily detected by loss of expression by immunohistochemistry. Among adults, the majority of AT/RTs occurs in the cerebral hemispheres. A small number of adult AT/RTs involving the sellar and suprasellar region reported in the literature suggest a distinct clinical course for this group. Here, we describe detailed clinical and genetic characterization of 5 adult patients with AT/RTs involving the sellar and suprasellar region, and provide a review of the available clinical and genetic features of 22 previously reported cases in order to help increase our understanding of this unusual entity.

Inducing Different Brain Injury Levels Using Shock Wave Lithotripsy.

OBJECTIVES: To assess the feasibility of inducing different severities of shock wave (SW)-induced traumatic brain injury (TBI) using lithotripsy. METHODS: Wistar rats (n = 36) were divided into 2 groups: group 1 (n = 20) received 5 SW pulses, and group 2 (n = 16) received 15 SWs pulses. The SW pulses were delivered to the right side of the frontal cortex. Neurologic and behavioral assessments (Garcia test, beam walking, rotarod, and elevated plus maze) were performed at the baseline and at 3, 6, 24, 72, and 168 hours after injury. At day 7 after injury (168 hours), we performed cerebral angiography to assess the presence of cerebral vasospasm and vascular damage due to SW-induced TBI. At the conclusion of the study, the animals were euthanized to assess damage to brain tissue using an overall histologic severity score. RESULTS: The Garcia score was significantly higher, and the anxiety index (based on the elevated plus maze) was significantly lower in group 1 compared to group 2 (P < .05). The anxiety index for group 1 returned to the baseline level in a fast nonlinear fashion, whereas the anxiety index for group 2 followed a distinct slow linear reduction. Cerebral angiograms revealed a more severe vasospasm for the animals in group 2 compared to group 1 (P = .027). We observed a statistically significant difference in the overall histologic severity scores between the groups. The median (interquartile range) overall histologic severity scores for groups 1 and 2 were 3.0 (2.75) and 6.5 (6.0), respectively (P = .023). CONCLUSIONS: We have successfully established different SW-induced TBI severities in our SW-induced TBI model by delivering different numbers of SW pulses to brain tissue.

Changes in [18F]Fluorodeoxyglucose Activities in a Shockwave-Induced Traumatic Brain Injury Model Using Lithotripsy.

We present a longitudinal study of cerebral metabolism using [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in a rat model of shockwave-induced traumatic brain injury (SW-TBI). Anesthetized rats received 5 or 10 SW pulses to the right anterior lateral or dorsal frontal regions using SW lithotripsy. Animals were scanned for FDG uptake at baseline, 3 h post-injury, and 3 days post-injury, using a small animal PET/computed tomography (CT) scanner. FDG uptake at all time-points was quantified as the ratio of brain activity relative to peripheral activity in the left ventricle (LV) in the heart (Abrain/ALV) for the entire brain, each hemisphere, and four cortices (motor, cingulate, somatosensory, and retrosplenial). The mixed-designed models analysis of variance (ANOVA) for the hemispheric and global FDG uptake ratio showed a significant effect of the time-of-scan (p = 0.038) and measured region (p = 6.12e-09). We also observed a significant effect of the time-of-scan (p = 0.046) and measured region (p = 2.28e-09) for the FDG uptake ratio in four cortical regions. None of the measurements (global or local) showed a significant effect for the number of SW pulses (5 or 10) or SW location (lateral or dorsal frontal regions). Our data suggest that SW-TBI causes hypermetabolism on the impact side of the rat brain at 3 h post-injury compared with the baseline measurements. However, the increase in FDG uptake by day 3 post-injury was not significant. Further studies on post-TBI metabolic changes are needed to understand better the pathophysiology of the injury.

Successful treatment of pituitary carcinoma with concurrent radiation, temozolomide, and bevacizumab after resection.

The optimal treatment of pituitary carcinomas (PC) is unknown. Treatment includes surgical resection, radiation, and more recently, temozolomide (TMZ). Pituitary adenomas have relatively high expression of vascular endothelial growth factor; therefore, bevacizumab, an antiangiogenic agent, has been used in a small number of aggressive or malignant pituitary tumors after recurrence. However, it has not been administered concurrently with other chemotherapeutic agents or combined with radiation therapy in PC. We present a 63-year-old man with an adrenocorticotropic hormone (ACTH)-secreting PC, causing visual loss. It was resected transsphenoidally. There were several notable factors placing the patient at high risk for recurrence including distant metastasis in the form of a pulmonary nodule. Morphologically, his tumor was a pituitary neoplasm with malignant histopathologic features. It had abundant mitotic figures and zones of necrosis. Six weeks post-surgery, the patient started concurrent chemoradiation, using combination therapy with TMZ and bevacizumab. TMZ was continued for 12 cycles in the adjuvant setting. The ACTH was effective as a serum-based tumor marker and normalized during treatment. The patient is alive, five years after diagnosis, with no recurrence to date. This is the first case of pituitary carcinoma treated successfully with concurrent chemoradiation therapy that combined TMZ and bevacizumab with a long-term follow up.

Biphasic Dependence of Glioma Survival and Cell Migration on CD44 Expression Level.

While several studies link the cell-surface marker CD44 to cancer progression, conflicting results show both positive and negative correlations with increased CD44 levels. Here, we demonstrate that the survival outcomes of genetically induced glioma-bearing mice and of high-grade human glioma patients are biphasically correlated with CD44 level, with the poorest outcomes occurring at intermediate levels. Furthermore, the high-CD44-expressing mesenchymal subtype exhibited a positive trend of survival with increased CD44 level. Mouse cell migration rates in ex vivo brain slice cultures were also biphasically associated with CD44 level, with maximal migration corresponding to minimal survival. Cell simulations suggest that cell-substrate adhesiveness is sufficient to explain this biphasic migration. More generally, these results highlight the potential importance of non-monotonic relationships between survival and biomarkers associated with cancer progression.

A Unique Case of an Aggressive Gangliocytic Paraganglioma of the Filum Terminale.

Paragangliomas are rare neuroendocrine tumors that are mostly found in the head and neck. Even less common are gangliocytic variant paragangliomas of the spine for which there are only 7 other documented cases in the literature. We report a case of gangliocytic paraganglioma of the sacral spine in a 68-year-old man. The growth pattern is documented over three years, which to our knowledge has not previously been reported in the literature and is different from the natural history. Clinical, radiological, and pathological characteristics of the tumor are discussed in light of available reports of this rare tumor.

Neuropathology of JC virus infection in progressive multifocal leukoencephalopathy in remission.

AIM: To investigate the neuropathology of the brain in a rare case of remission following diagnosis of progressive multifocal leukoencephalopathy (PML). METHODS: Consent from the family for an autopsy was obtained, clinical records and radiograms were retrieved. A complete autopsy was performed, with brain examination after fixation and coronal sectioning at 1 cm intervals. Fourteen regions were collected for paraffin embedding and staining for microscopic analysis. Histologic sections were stained with Luxol blue, hematoxylin/eosin, and immunostained for myelin basic protein, neurofilament, SV40 T antigen and p53. The biopsy material was also retrieved and sections were stained with hematoxylin/eosin and immunostained for SV40 and p53. Sections were examined by American Board of Pathology certified pathologists and images captured digitally. RESULTS: Review of the clinical records was notable for a history of ulcerative colitis resulting in total colectomy in 1977 and a liver transplant in 1998 followed by immune-suppressive therapy. Neurological symptoms presented immediately, therefore a biopsy was obtained which was diagnosed as PML. Immunotherapy was adjusted and clinical improvement was noted. No subsequent progression was reported. Review of the biopsy demonstrated atypical astrocytes and enlarged hyperchromatic oligodendroglial cells consistent with JC virus infection. Strong SV40 and p53 staining was found in glial cells and regions of dense macrophage infiltration were present. On gross examination of the post-mortem brain, a lesion in the same site as the original biopsy in the cerebellum was identified but no other lesions in the brain were found. Microscopic analysis of this cerebellar lesion revealed a loss of myelin and axons, and evidence of axonal damage. This single burned-out lesion was equivocally positive for SV40 antigen with little p53 staining. Examination of thirteen other brain regions found no other occult sites. CONCLUSION: Our study reveals residual damage, rare macrophages or other inflammation and minimal evidence of persistent virus. This case demonstrates the possibility of complete remission of PML.

A Novel Preclinical Model of Moderate Primary Blast-Induced Traumatic Brain Injury.

Blast-induced traumatic brain injury (bTBI) is the "signature" injury of the recent Iraq and Afghanistan wars. Here, we present a novel method to induce bTBI using shock wave (SW) lithotripsy. Using a lithotripsy machine, Wistar rats (N = 70; 408.3 ± 93 g) received five SW pulses to the right side of the frontal cortex at 24 kV and a frequency of 60 Hz. Animals were then randomly divided into three study endpoints: 24 h (n = 25), 72 h (n = 19) and 168 h (n = 26). Neurological and behavioral assessments (Garcia's test, beam walking, Rotarod, and elevated plus maze) were performed at the baseline, and further assessments followed at 3, 6, 24, 72, and 168 h post-injury, if applicable. We performed digital subtraction angiography (DSA) to assess presence of cerebral vasospasm due to induced bTBI. Damage to brain tissue was assessed by an overall histological severity (OHS) score based on depth of injury, area of hemorrhage, and extent of axonal injury. Except for beam walking, OHS was significantly correlated with the other three outcome measures with at least one of their assessments during the first 6 h after the experiment. OHS manifested the highest absolute correlation coefficients with anxiety at the baseline and 6 h post-injury (r(baseline) = -0.75, r(6hrs) = 0.85; p<0.05). Median hemispheric differences for contrast peak values (obtained from DSA studies) for 24, 72, and 168 h endpoints were 3.45%, 3.05% and 0.2%, respectively, with statistically significant differences at 1 versus 7 d (p<0.05) and 3 versus 7 d (p<0.01). In this study, we successfully established a preclinical rat model of bTBI with characteristics similar to those observed in clinical cases. This new method may be useful for future investigations aimed at understanding bTBI pathophysiology.

Fatal Granulomatous Amebic Encephalitis Due to Balamuthia mandrillaris in New Mexico: A Case Report.

Balamuthia mandrillaris is a free-living amoeba that can cause granulomatous amebic encephalitis (GAE). We report a case in an individual with a history of alcohol abuse, cocaine use, and ditch water exposure. This is the first reported case of GAE due to B mandrillaris in New Mexico.

Vaccination for invasive canine meningioma induces in situ production of antibodies capable of antibody-dependent cell-mediated cytotoxicity.

Malignant and atypical meningiomas are resistant to standard therapies and associated with poor prognosis. Despite progress in the treatment of other tumors with therapeutic vaccines, this approach has not been tested preclinically or clinically in these tumors. Spontaneous canine meningioma is a clinically meaningful but underutilized model for preclinical testing of novel strategies for aggressive human meningioma. We treated 11 meningioma-bearing dogs with surgery and vaccine immunotherapy consisting of autologous tumor cell lysate combined with toll-like receptor ligands. Therapy was well tolerated, and only one dog had tumor growth that required intervention, with a mean follow up of 585 days. IFN-γ-elaborating T cells were detected in the peripheral blood of 2 cases, but vaccine-induced tumor-reactive antibody responses developed in all dogs. Antibody responses were polyclonal, recognizing both intracellular and cell surface antigens, and HSP60 was identified as one common antigen. Tumor-reactive antibodies bound allogeneic canine and human meningiomas, showing common antigens across breed and species. Histologic analysis revealed robust infiltration of antibody-secreting plasma cells into the brain around the tumor in posttreatment compared with pretreatment samples. Tumor-reactive antibodies were capable of inducing antibody-dependent cell-mediated cytotoxicity to autologous and allogeneic tumor cells. These data show the feasibility and immunologic efficacy of vaccine immunotherapy for a large animal model of human meningioma and warrant further development toward human trials.

Active efflux of Dasatinib from the brain limits efficacy against murine glioblastoma: broad implications for the clinical use of molecularly targeted agents.

The importance of the blood-brain barrier in preventing effective pharmacotherapy of glioblastoma has been controversial. The controversy stems from the fact that vascular endothelial cell tight junctions are disrupted in the tumor, allowing some systemic drug delivery. P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) efflux drugs from brain capillary endothelial cells into the blood. We tested the hypothesis that although the tight junctions are "leaky" in the core of glioblastomas, active efflux limits drug delivery to tumor-infiltrated normal brain and consequently, treatment efficacy. Malignant gliomas were induced by oncogene transfer into wild-type (WT) mice or mice deficient for Pgp and BCRP (knockout, KO). Glioma-bearing mice were orally dosed with dasatinib, a kinase inhibitor and dual BCRP/PgP substrate that is being currently tested in clinical trials. KO mice treated with dasatinib survived for twice as long as WT mice. Microdissection of the tumor core, invasive rim, and normal brain revealed 2- to 3-fold enhancement in dasatinib brain concentrations in KO mice relative to WT. Analysis of signaling showed that poor drug delivery correlated with the lack of inhibition of a dasatinib target, especially in normal brain. A majority of human glioma xenograft lines tested expressed BCRP or PgP and were sensitized to dasatinib by a dual BCRP/Pgp inhibitor, illustrating a second barrier to drug delivery intrinsic to the tumor itself. These data show that active efflux is a relevant obstacle to treating glioblastoma and provide a plausible mechanistic basis for the clinical failure of numerous drugs that are BCRP/Pgp substrates.