Transcriptional landscape of human microglia implicates age, sex, and APOE-related immunometabolic pathway perturbations

Microglia have fundamental roles in health and disease; however, effects of age, sex, and genetic factors on human microglia have not been fully explored. We applied bulk and single-cell approaches to comprehensively characterize human microglia transcriptomes and their associations with age, sex, and APOE. We identified a novel microglial signature, characterized its expression in bulk tissue and single-cell microglia transcriptomes. We discovered microglial co-expression network modules associated with age, sex, and APOE-ε4 that are enriched for lipid and carbohydrate metabolism genes. Integrated analyses of modules with single-cell transcriptomes revealed significant overlap between age-associated module genes and both pro-inflammatory and disease-associated microglial clusters. These modules and clusters harbor known neurodegenerative disease genes including APOE, PLCG2, and BIN1. Meta-analyses with published bulk and single-cell microglial datasets further supported our findings. Thus, these data represent a well-characterized human microglial transcriptome resource and highlight age, sex, and APOE-related microglial immunometabolism perturbations with potential relevance in neurodegeneration.

Examining the function of the visual word form area with stereo EEG electrical stimulation: A case report of pure alexia

Functional imaging studies have implicated an area in the left lateral fusiform gyrus, known as the visual word form area (VWFA), in pre-lexical orthographic processing. There are very few studies that have examined the functional specificity of this area in patients with discrete lesions limited to this region. Here we describe a rare opportunity to examine the functional specificity of the VWFA in a patient with stereo EEG (sEEG) electrodes implanted for localization of seizures prior to epilepsy surgery. sEEG offers the opportunity to create a transient and highly localized electrophysiological lesion to examine brain behavior correlates during functional mapping. In this case, word reading and writing as well as a variety of non-orthographic language functions (e.g., picture and face naming, auditory naming, and non-word repetition), were tested during electrical stimulation at a series of different electrode contact sites in the ventral temporal region. Pure alexia resulted from stimulation of the lateral fusiform gyrus at coordinates nearly identical to those published for the VWFA in the functional imaging literature.

Real-time Video-Streaming to Surgical Loupe Mounted Head-Up Display for Navigated Meningioma Resection

AIM

Wearable technology interfaces with normal human movement and function, thereby enabling more efficient and adaptable use.We developed a wearable display system for use with intra-operative neuronavigation for brain tumor surgery.

MATERIAL AND METHODS

The Google glass head-up display system was adapted to surgical loupes with a video-streaming integrated hardware and software device for display of the Stealth S7 navigation screen. Phantom trials of surface ventriculostomy were performed. The device was utilized as an alternative display screen during cranial surgery.

RESULTS

Image-guided brain tumor resection was accomplished using Google Glass head-up display of Stealth S7 navigation images. Visual display consists of navigation video-streaming over a wireless network. The integrated system developed for video-streaming permits video data display to the operating surgeon without requiring movement of the head away from the operative field.

CONCLUSION

Google Glass head-up display can be used for intra-operative neuronavigation in the setting of intracranial tumor resection.

Multiple Calcifying Pseudoneoplasms of the Neuraxis

Calcifying pseudoneoplasms of the neuraxis (CAPNONs) are extremely rare tumors that are frequently misdiagnosed and overlooked by clinicians. To date, only 40 intracranial lesions have been reported, and in all instances, they were found as a solitary calcified mass. To our knowledge, the current case report is the first to illustrate the development of multiple intraaxial CAPNONs and shed more light on the origin of these lesions.

We discuss the case of a 67-year-old woman who presented with a six-year history of recurrent seizures. Magnetic resonance imaging revealed two similar heterogeneous intracranial masses in the ventral midbrain and left frontal white matter with indications of more aggressive behavior in the supratentorial tumor. The lesion was resected, and histopathological analysis showed tissue containing nodules of chondromyxoid material with a coarsely fibrillar matrix and focal alveolar pattern. Palisading cells were noted around the edges as well as dystrophic calcifications and osseous metaplasia, consistent with CAPNON. Interestingly, the patient had a previous history of multiple brain abscesses and a mycotic aneurysm. At her four-month follow-up visit, the patient remained seizure-free and there were no indications of residual tumor or recurrence.

In contrast to previous reports, intracranial CAPNONs may manifest as multiple lesions and clinicians should include these tumors in the differential diagnosis of intra-axial calcified masses. The previous history of brain abscesses raises the suspicion of an abnormal proliferative process following an insult to the brain tissue as the underlying origin of these lesions.

Ambulance-based assessment of NIH Stroke Scale with telemedicine: A feasibility pilot study

Background Ischemic stroke is a time-sensitive disease, with improved outcomes associated with decreased time from onset to treatment. It was hypothesised that ambulance-based assessment of the National Institutes of Health Stroke Scale (NIHSS) using a Health Insurance Portability and Accountability Act (HIPAA)-compliant mobile platform immediately prior to arrival is feasible. Methods This is a proof-of-concept feasibility pilot study in two phases. The first phase consisted of an ambulance-equipped HIPAA-compliant video platform for remote NIHSS assessment of a simulated stroke patient. The second phase consisted of remote NIHSS assessment by a hospital-based neurologist of acute stroke patients en route to our facility. Five ambulances were equipped with a 4G/LTE-enabled tablet preloaded with a secure HIPAA-compliant telemedicine application. Secondary outcomes assessed satisfaction of staff with the remote platform. Results Phase one was successful in the assessment of three out of three simulated patients. Phase two was successful in the assessment of 10 out of 11 (91%) cases. One video attempt was unsuccessful because local LTE was turned off on the device. The video signal was dropped transiently due to weather, which delayed NIHSS assessment in one case. Average NIHSS assessment time was 7.6 minutes (range 3-9.8 minutes). Neurologists rated 83% of encounters as 'satisfied' to 'very satisfied', and the emergency medical service (EMS) rated 90% of encounters as 'satisfied' to 'very satisfied'. The one failed video attempt was associated with 'poor' EMS satisfaction. Conclusion This proof-of-concept pilot demonstrates that remote ambulance-based NIHSS assessment is feasible. This model could reduce door-to-needle times by conducting prehospital data collection.

Long-term treatment with responsive brain stimulation in adults with refractory partial seizures

OBJECTIVE

The long-term efficacy and safety of responsive direct neurostimulation was assessed in adults with medically refractory partial onset seizures.

METHODS

All participants were treated with a cranially implanted responsive neurostimulator that delivers stimulation to 1 or 2 seizure foci via chronically implanted electrodes when specific electrocorticographic patterns are detected (RNS System). Participants had completed a 2-year primarily open-label safety study (n = 65) or a 2-year randomized blinded controlled safety and efficacy study (n = 191); 230 participants transitioned into an ongoing 7-year study to assess safety and efficacy.

RESULTS

The average participant was 34 (±11.4) years old with epilepsy for 19.6 (±11.4) years. The median preimplant frequency of disabling partial or generalized tonic-clonic seizures was 10.2 seizures a month. The median percent seizure reduction in the randomized blinded controlled trial was 44% at 1 year and 53% at 2 years (p < 0.0001, generalized estimating equation) and ranged from 48% to 66% over postimplant years 3 through 6 in the long-term study. Improvements in quality of life were maintained (p < 0.05). The most common serious device-related adverse events over the mean 5.4 years of follow-up were implant site infection (9.0%) involving soft tissue and neurostimulator explantation (4.7%).

CONCLUSIONS

The RNS System is the first direct brain responsive neurostimulator. Acute and sustained efficacy and safety were demonstrated in adults with medically refractory partial onset seizures arising from 1 or 2 foci over a mean follow-up of 5.4 years. This experience supports the RNS System as a treatment option for refractory partial seizures.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for adults with medically refractory partial onset seizures, responsive direct cortical stimulation reduces seizures and improves quality of life over a mean follow-up of 5.4 years.

True- true- unrelated? A delayed onset, complete third-nerve palsy after traumatic subarachnoid hemorrhage

A 61-year-old male presented to the emergency department (ED) with painless diplopia, left-ptosis, and left downward gaze, 3 days after sustaining a fall from standing height with subsequent lumbar and head trauma. Prior to the ED consult, his only symptom was persistent generalized high intensity headache. On physical examination, no other neurological deficit was found. Computed tomography (CT) scan showed Fisher 4 subarachnoid hemorrhage (SAH). Cerebral angiogram and brain magnetic resonance imaging (MRI) were negative. Screening for possible secondary causes of isolated third-nerve palsy (TNP) were all negative. To our knowledge, this is the first report of a traumatic SAH with delayed onset of an isolated complete TNP as its manifestation.

CONFLICTS OF INTEREST/DISCLOSURES

None pertinent to this research.

AUTHOR JUSTIFICATIONS

All authors have provided original or professional content and were involved in the clinical care of the patient.

LIST OF ABBREVIATIONS

CNcranial nerveDSAdigital subtraction angiogramGCSGlasgow Coma ScalePCOMposterior communicating arterySAHsubarachnoid hemorrhageTNPthird nerve palsytSAHtraumatic SAH.

Spontaneous activation and signaling by overexpressed epidermal growth factor receptors in glioblastoma cells

Overexpressed epidermal growth receptor factor receptors (EGFRs) are thought to contribute to the malignant phenotype of human glioblastomas (GBMs), but the mechanism is not well understood. We found that SKMG-3 cells, a rare GBM cell line that maintains EGFR gene amplification in vitro, produced high levels of EGFR protein. The cells also expressed the related receptors HER2/neu and HER4, but not HER3. Immunoblots and tryptic phosphopeptide maps showed that the SKMG-3 EGFRs were intact and functional and that a subset of these receptors were spontaneously autophosphorylated. EGF treatment stimulated phosphorylation of the EGFRs as well as the downstream effectors Erk, AKT1, stat3 and c-Cbl. Under minimal growth conditions, the unstimulated SKMG-3 cells contained constitutively phosphorylated Erk and AKTI but no detectable stat3 DNA-binding complexes. The EGFR kinase inhibitor PD158780 reduced the constitutive phosphorylation of the receptor and Erk but not that of AKT1. In contrast, inhibition of phosphatidylinositol-3-kinase (PI3K) blocked the constitutive phosphorylation of Erk and AKT-1 but not the EGFR. We conclude that the SKMG-3 cells represent the subset of GBMs with amplified EGFR genes that overexpress intact receptors. The results also suggest that in some GBMs, signals from overexpressed EGFRs contribute to the constitutive phosphorylation of Erk, but these signals may not required for the constitutive activation of PI3K or AKT1.

Glioblastoma-related gene mutations and over-expression of functional epidermal growth factor receptors in SKMG-3 glioma cells

Amplification of the epidermal growth factor receptor (EGFR) gene is found in about 40% of glioblastomas (GBMs) but is rarely detected in GBM cell lines. We confirmed that the exceptional SKMG-3 GBM cell line retained amplified EGFR genes in vitro, and found that these sequences were concentrated on extra-chromosomal DNA particles similar to double-minute chromosomes. The cells contained two other gene mutations that are associated with high-grade astrocytic tumors: extra-chromosomal amplification of the cyclin-dependent kinase-4 (CDK4) gene and a homozygous mutation within the PTEN tumor suppressor gene. Immunoblots revealed very high levels of EGFR, moderately increased expression of CDK4, and no detectable PTEN protein. The overexpressed SKMG-3 EGFRs responded to exogenous ligand and resembled normal rather than mutant receptors. A heterozygous mutation of the p53 gene (p53R282W) correlated with failure of radiation to induce the expression of cyclin-dependent kinase inhibitor p21waf1 or an early G1 cell cycle arrest. Although each of these gene mutations occurs in GBMs, SKMG-3 cells had an unusual genotype in that a p53 gene mutation co-existed with amplified EGFR genes. Nonetheless, the SKMG-3 cell line can be exploited as a model to study how oncogenic EGFR signals in GBM cells interact with over-expressed CDK4 and loss of PTEN to confer the malignant phenotype.

Metro Stroke Task Force Survey of Resources for Diagnosis of Non-Traumatic Subarachnoid Hemorrhage

P9

Background: Up to 25 percent of patients with subarachnoid hemorrhage (SAH)initially receive an incorrect diagnosis. Potential limitations to initially diagnosing SAH include insufficient resources and non-standardized utilization of existing resources. We performed a population-based study to assess adherence to recommendations regarding computed tomography (CT) scanning and cerebrospinal fluid (CSF) analysis as cited in a recent publication. Methods: We approached all hospitals with operational emergency departments within a 50 mile radius of downtown Jacksonville, FL. Each facility was contacted by phone or in person by one of two members of the Metro Stroke Task Force (SPD,SS). Included in the survey were groups of questions each directed to a physician or technician best qualified to provide appropriate information. We used the recommendations cited by Edlow and Caplan as a benchmark for diagnosing SAH acutely (cf. New Engl J Med 2000; 342:29–36). Specifically addressed were the axial imaging slice thickness on head CT and methods for analyzing cerebrospinal fluid for blood and blood products. Results: 13 of 13 (100%) hospitals responded. 7 of 13 (54%) have 200 or more beds. 10 of 13 (77%) have neurosurgeons on staff. None (0%) of the hospitals surveyed cited a specific protocol for head CT scanning or CSF analysis in the evaluation of suspected subarachnoid hemorrhage. One (7.7%) hospital used CT cuts as thin at the base of the brain as the 3mm recommended. None (0%) of the hospitals routinely used spectrophotometry to evaluate for the presence of xanthochromia in CSF when ruling out SAH. Conclusion: We found that there is not a uniform and specific way to approach the diagnosis of SAH among all of the institutions that provide acute care within a 50 mile radius of Jacksonville. Areas for improvement in delivery of care might include standardized protocols for CT acquisition and CSF analysis for blood and blood products. Such standardized measures may reduce the potential for initial diagnostic errors.