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Acta Neurochirurgica Jan 2024Technological (and also methodological) advances in neurosurgery and neuroimaging have prompted a reappraisal of Simpson's grading of the extent of meningioma... (Review)
Review
Technological (and also methodological) advances in neurosurgery and neuroimaging have prompted a reappraisal of Simpson's grading of the extent of meningioma resections. To the authors, the published evidence supports the tenets of this classification. Meningioma is an often surgically curable dura-based disease. An extent of meningioma resection classification needs to account for a clinically meaningful variation of the risk of recurrence depending on the aggressiveness of the management of the (dural) tumor origin.Nevertheless, the 1957 Simpson classification undoubtedly suffers from many limitations. Important issues include substantial problems with the applicability of the grading paradigm in different locations. Most notably, tumor location and growth pattern often determine the eventual extent of resection, i.e., the Simpson grading does not reflect what is surgically achievable. Another very significant problem is the inherent subjectivity of relying on individual intraoperative assessments. Neuroimaging advances such as the use of somatostatin receptor PET scanning may help to overcome this central problem. Tumor malignancy and biology in general certainly influence the role of the extent of resection but may not need to be incorporated in an actual extent of resection grading scheme as long as one does not aim at developing a prognostic score. Finally, all attempts at grading meningioma resections use tumor recurrence as the endpoint. However, especially in view of radiosurgery/radiotherapy options, the clinical significance of recurrent tumor growth varies greatly between cases.In summary, while the extent of resection certainly matters in meningioma surgery, grading resections remains controversial. Given the everyday clinical relevance of this issue, a multicenter prospective register or study effort is probably warranted (including a prominent focus on advanced neuroimaging).
Topics: Humans; Meningioma; Neurosurgical Procedures; Dura Mater; Neuroimaging; Meningeal Neoplasms; Multicenter Studies as Topic
PubMed: 38261164
DOI: 10.1007/s00701-024-05910-9 -
Neurospine Dec 2023Syringomyelia is a common central nervous system disease characterized by the dilation of the central canal (CC). Regarding the pathogenesis of syringomyelia,...
OBJECTIVE
Syringomyelia is a common central nervous system disease characterized by the dilation of the central canal (CC). Regarding the pathogenesis of syringomyelia, cerebrospinal fluid (CSF) circulation obstruction in the subarachnoid space (SAS) of the spinal cord has been widely accepted. However, clinical and animal studies on obstructing the CSF in SAS failed to form syringomyelia, challenging the theory of SAS obstruction. The precise pathogenesis remains unknown.
METHODS
We utilized an extradural compression rat model to investigate the pathogenesis underlying syringomyelia. Magnetic resonance imaging enabled detection of syringomyelia formation. To assess CSF flow within the SAS, Evans blue was infused into the cisterna magna. Histological analysis allowed morphological examination of the CC. Furthermore, CSF flow through the CC was traced using Ovalbumin Alexa-Flour 647 conjugate (OAF-647). Scanning electron microscopy (SEM) enabled visualization of ependymal cilia.
RESULTS
The findings showed that the dura mater below the compression segment exhibited lighter coloration relative to the region above the compression, indicative of partial obstruction within the SAS. However, the degree of SAS occlusion did not significantly differ between syringomyelia (SM-Y group) and those without (SM-N group). Intriguingly, hematoxylin and eosin staining and CSF tracing revealed occlusion of the CC accompanied by reduced CSF flow in the SM-Y group compared to SM-N and control groups. SEM images uncovered impairment of ependymal cilia inside the syringomyelia.
CONCLUSION
CC occlusion may represent a physiological prerequisite for syringomyelia formation, while SAS obstruction serves to initiate disease onset. The impairment of ependymal cilia appears to facilitate progression of syringomyelia.
PubMed: 38171302
DOI: 10.14245/ns.2346834.417 -
Translational Oncology Jun 2024Tumor derived Extracellular vesicles (EVs) in circulating system may contain tumor-specific markers, and EV detection in body fluids could become an important tool for...
Tumor derived Extracellular vesicles (EVs) in circulating system may contain tumor-specific markers, and EV detection in body fluids could become an important tool for early tumor diagnosis, prognosis assessment. Meningiomas are the most common benign intracranial tumors, few studies have revealed specific protein markers for meningiomas from patients' body fluids. In this study, using proximity labeling technology and non-tumor patient plasma as a control, we detected protein levels of EVs in plasma samples from meningioma patients before and after surgery. Through bioinformatics analysis, we discovered that the levels of EV count and protein count in meningioma patients were significantly higher than those in healthy controls, and were significantly decreased postoperatively. Among EV proteins in meningioma patients, the levels of MUC1, SIGLEC11, E-Cadherin, KIT, and TASCTD2 were found not only significantly elevated than those in healthy controls, but also significantly decreased after tumor resection. Moreover, using publicly available GEO databases, we verified that the mRNA level of MUC1, SIGLEC11, and CDH1 in meningiomas were significantly higher in comparison with normal dura mater tissues. Additionally, by analyzing human meningioma specimens collected in this study, we validated the protein levels of MUC1 and SIGLEC11 were significantly increased in WHO grade 2 meningiomas and were positively correlated with tumor proliferation levels. This study indicates that meningiomas secret EV proteins into circulating system, which may serve as specific markers for diagnosis, malignancy predicting and tumor recurrent assessment.
PubMed: 38943923
DOI: 10.1016/j.tranon.2024.102046 -
Nature Communications Jun 2024B cells and T cells collaborate in multiple sclerosis (MS) pathogenesis. IgH mice possess a B cell repertoire skewed to recognize myelin oligodendrocyte glycoprotein...
B cells and T cells collaborate in multiple sclerosis (MS) pathogenesis. IgH mice possess a B cell repertoire skewed to recognize myelin oligodendrocyte glycoprotein (MOG). Here, we show that upon immunization with the T cell-obligate autoantigen, MOG, IgH mice develop rapid and exacerbated experimental autoimmune encephalomyelitis (EAE) relative to wildtype (WT) counterparts, characterized by aggregation of T and B cells in the IgH meninges and by CD4 T helper 17 (Th17) cells in the CNS. Production of the Th17 maintenance factor IL-23 is observed from IgH CNS-infiltrating and meningeal B cells, and in vivo blockade of IL-23p19 attenuates disease severity in IgH mice. In the CNS parenchyma and dura mater of IgH mice, we observe an increased frequency of CD4PD-1CXCR5 T cells that share numerous characteristics with the recently described T peripheral helper (Tph) cell subset. Further, CNS-infiltrating B and Tph cells from IgH mice show increased reactive oxygen species (ROS) production. Meningeal inflammation, Tph-like cell accumulation in the CNS and B/Tph cell production of ROS were all reduced upon p19 blockade. Altogether, MOG-specific B cells promote autoimmune inflammation of the CNS parenchyma and meninges in an IL-23-dependent manner.
Topics: Animals; Encephalomyelitis, Autoimmune, Experimental; B-Lymphocytes; Myelin-Oligodendrocyte Glycoprotein; Mice; Autoimmunity; Interleukin-23; CD4-Positive T-Lymphocytes; Th17 Cells; Central Nervous System; Mice, Inbred C57BL; Female; Myelin Sheath; Meninges; Multiple Sclerosis
PubMed: 38926356
DOI: 10.1038/s41467-024-49259-0 -
Revista Espanola de Cirugia Ortopedica... Oct 2023Traumatic spinal cord injury (SCI) leads to increased intraspinal pressure that can be prevented by durotomy and duroplasty. The aim of the study was to evaluate...
INTRODUCTION
Traumatic spinal cord injury (SCI) leads to increased intraspinal pressure that can be prevented by durotomy and duroplasty. The aim of the study was to evaluate fibrosis and neural damage in a porcine model of SCI after duroplasty and application of hyaluronic acid (HA) in the tissue cavity.
MATERIALS AND METHODS
Experimental study. We created a porcine SCI model by durotomy and spinal cord hemisection of a cervical segment (1cm). Six pigs (Sus scrofa domestica) were used to evaluate three surgical scenarios: (1)control injury with dural reparative microsurgery, (2)duroplasty using bovine pericardium (BPD), and (3)previous method plus HA applied at the lesion. Animals were sacrificed one-month post-injury to assess fibrotic responses and neural tissue damage using conventional histological and immunohistochemical methods.
RESULTS
In the control case, dural suture prevented invasion of the lesion by extradural connective tissue, and the dura mater showed a 1-mm thickening in the perilesional area. The bovine pericardium patch blocked the entrance of extradural connective tissue, decreased dura-mater tension, and satisfactorily integrated within the receptor tissue. However, it also enhanced subdural and perilesional fibrosis, which was not inhibited by filling the lesion cavity with low- or high-molecular-weight HA.
CONCLUSIONS
Duroplasty prevents collapse of the dura-mater over the spinal cord tissue, as well as invasion of the lesion by extramedullary fibrotic tissue, without creating additional neural damage. Nevertheless, it enhances the fibrotic response in the spinal cord lesion and the perilesional area. Additional antifibrotic strategies are needed to facilitate spinal cord repair.
PubMed: 37802396
DOI: 10.1016/j.recot.2023.09.008 -
Journal of Toxicologic Pathology Apr 2024In neurosurgical interventions, effective closure of the dura mater is essential to prevent cerebrospinal fluid leakage and minimize post-operative complications....
In neurosurgical interventions, effective closure of the dura mater is essential to prevent cerebrospinal fluid leakage and minimize post-operative complications. Biodegradable synthetic materials have the potential to be used as dura mater grafts owing to their regenerative properties and low immunogenicity. This study evaluated the safety of ArtiFascia, a synthetic dura mater graft composed of poly(l-lactic-co-caprolactone acid) and poly(d-lactic-co-caprolactone acid), in a rabbit durotomy model. Previously, ArtiFascia demonstrated positive local tolerance and biodegradability in a 12-month preclinical trial. Here, specialized stains were used to evaluate potential brain damage associated with ArtiFascia use. Histochemical and immunohistochemical assessments included Luxol Fast Blue, cresyl Violet, Masson's Trichrome, neuronal nuclei,, Glial Fibrillary Acidic Protein, and ionized calcium-binding adaptor molecule 1 stains. The stained slides were graded based on the brain-specific reactions. The results showed no damage to the underlying brain tissue for either the ArtiFascia or control implants. Neither inflammation nor neuronal loss was evident, corroborating the safety of the ArtiFascia. This approach, combined with previous histopathological analyses, strengthens the safety profile of ArtiFascia and sets a benchmark for biodegradable material assessment in dura graft applications. This study aligns with the Food and Drug Administration guidelines and offers a comprehensive evaluation of the potential neural tissue effects of synthetic dura mater grafts.
PubMed: 38584968
DOI: 10.1293/tox.2023-0121 -
Journal of Korean Neurosurgical Society Mar 2024Chronic subdural hematomas (cSDHs) are generally known to result from traumatic tears of bridging veins. However, the causes of repeat spontaneous cSDHs are still...
OBJECTIVE
Chronic subdural hematomas (cSDHs) are generally known to result from traumatic tears of bridging veins. However, the causes of repeat spontaneous cSDHs are still unclear. We investigated the changes in vasculature in the human dura mater and outer membrane (OM) of cSDHs to elucidate the cause of their spontaneous repetition.
METHODS
The dura mater was obtained from a normal control participant and a patient with repeat spontaneous cSDHs. The pathological samples from the patient included the dura mater and OM tightly adhered to the inner dura. The samples were analyzed with a particular focus on blood and lymphatic vessels by immunohistochemistry, 3-dimensional imaging using a transparent tissue clearing technique, and electron microscopy.
RESULTS
The dural border cell (DBC) layer of the dura mater and OM were histologically indistinguishable. There were 5.9 times more blood vessels per unit volume of tissue in the DBC layer and OM in the patient than in the normal control. The DBC layer and OM contained pathological sinusoidal capillaries not observed in the normal tissue; these capillaries were connected to the middle meningeal arteries via penetrating arteries. In addition, marked lymphangiogenesis in the periosteal and meningeal layers was observed in the patient with cSDHs.
CONCLUSION
Neovascularization in the OM seemed to originate from the DBC layer; this is a potential cause of repeat spontaneous cSDHs. Embolization of the meningeal arteries to interrupt the blood supply to pathological capillaries via penetrating arteries may be an effective treatment option.
PubMed: 38213004
DOI: 10.3340/jkns.2023.0105 -
IDCases 2023Spinal epidural abscess (SEA) is an abscess that forms between the dura mater and vertebrae. SEA is characterized by back pain and neuropathy associated with fever, of...
Spinal epidural abscess (SEA) is an abscess that forms between the dura mater and vertebrae. SEA is characterized by back pain and neuropathy associated with fever, of which early diagnosis and treatment are necessary to avoid irreversible neurological sequelae. However, its diagnosis is often difficult because specific symptoms are rarely present in the early stages of the disease. A 25-month-old boy, healthy by nature and free of risk factors, was referred and admitted for fever symptoms only, without back pain or neurological symptoms. We focused on the residual activation of the coagulation-fibrinolytic system, which was contrary to the response to therapy, and were able to establish a diagnosis of SEA. After the initiation of antibiotics, the patient responded well to treatment and made a mild recovery without the need for surgical intervention. To date, there are no reported cases of SEA with only febrile symptoms without localized spinal cord tenderness. SEA is easily overlooked and should be considered in the differential diagnosis of pediatric fever of unknown origin. Although imaging studies have drawbacks, such as radiation exposure and sedation, they should be immediately performed if SEA is suspected.
PubMed: 37680212
DOI: 10.1016/j.idcr.2023.e01887 -
ENeuro May 2024High-density linear probes, such as Neuropixels, provide an unprecedented opportunity to understand how neural populations within specific laminar compartments...
High-density linear probes, such as Neuropixels, provide an unprecedented opportunity to understand how neural populations within specific laminar compartments contribute to behavior. Marmoset monkeys, unlike macaque monkeys, have a lissencephalic (smooth) cortex that enables recording perpendicular to the cortical surface, thus making them an ideal animal model for studying laminar computations. Here we present a method for acute Neuropixels recordings in the common marmoset (). The approach replaces the native dura with an artificial silicon-based dura that grants visual access to the cortical surface, which is helpful in avoiding blood vessels, ensures perpendicular penetrations, and could be used in conjunction with optical imaging or optogenetic techniques. The chamber housing the artificial dura is simple to maintain with minimal risk of infection and could be combined with semichronic microdrives and wireless recording hardware. This technique enables repeated acute penetrations over a period of several months. With occasional removal of tissue growth on the pial surface, recordings can be performed for a year or more. The approach is fully compatible with Neuropixels probes, enabling the recording of hundreds of single neurons distributed throughout the cortical column.
Topics: Animals; Callithrix; Dura Mater; Neurons; Male; Female; Electrodes, Implanted; Cerebral Cortex; Optogenetics
PubMed: 38658139
DOI: 10.1523/ENEURO.0544-23.2024 -
BioRxiv : the Preprint Server For... Aug 2023Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic...
Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic inflammation in the central nervous system (CNS) - known as Neuro-HIV- persist. As primary targets for HIV-1 with the ability to survey and populate the CNS and interact with myeloid cells to co-ordinate neuroinflammation, CD4 T cells are pivotal in Neuro-HIV. Despite their importance, our understanding of CD4 T cell distribution in virus-targeted CNS tissues, their response to infection, and potential recovery following initiation of ART remain limited. To address these gaps, we studied ten SIVmac251-infected rhesus macaques using an ART regimen simulating suboptimal adherence. We evaluated four macaques during the acute phase pre-ART and six during the chronic phase. Our data revealed that HIV target CCR5+ CD4 T cells inhabit both the brain parenchyma and adjacent CNS tissues, encompassing choroid plexus stroma, dura mater, and the skull bone marrow. Aligning with the known susceptibility of CCR5+ CD4 T cells to viral infection and their presence within the CNS, high levels of viral RNA were detected in the brain parenchyma and its border tissues during acute SIV infection. Single-cell RNA sequencing of CD45+ cells from the brain revealed colocalization of viral transcripts within CD4 clusters and significant activation of antiviral molecules and specific effector programs within T cells, indicating CNS CD4 T cell engagement during infection. Despite viral suppression with ART, acute infection led to significant depletion of CNS CD4 T cells, persisting into the chronic phase. These findings underscore the functional involvement of CD4 T cells within the CNS during SIV infection, enhancing our understanding of their role in establishing CNS viral presence. Our results offer insights for potential T cell-focused interventions while also underscoring the challenges in eradicating HIV from the CNS, even with effective ART.
PubMed: 37662237
DOI: 10.1101/2023.08.24.554055