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Frontiers in Neuroscience 2022Sensory corpuscles, or cutaneous end-organ complexes, are complex structures localized at the periphery of Aβ-axon terminals from primary sensory neurons that primarily...
Sensory corpuscles, or cutaneous end-organ complexes, are complex structures localized at the periphery of Aβ-axon terminals from primary sensory neurons that primarily work as low-threshold mechanoreceptors. Structurally, they consist, in addition to the axons, of non-myelinating Schwann-like cells (terminal glial cells) and endoneurial- and perineurial-related cells. The terminal glial cells are the so-called lamellar cells in Meissner and Pacinian corpuscles. Lamellar cells are variably arranged in sensory corpuscles as a "coin stack" in the Meissner corpuscles or as an "onion bulb" in the Pacinian ones. Nevertheless, the origin and protein profile of the lamellar cells in both morphotypes of sensory corpuscles is quite similar, although it differs in the expression of mechano-gated ion channels as well as in the composition of the extracellular matrix between the cells. The lamellar cells have been regarded as supportive cells playing a passive role in the process of genesis of the action potential, i.e., the mechanotransduction process. However, they express ion channels related to the mechano-electric transduction and show a synapse-like mechanism that suggest neurotransmission at the genesis of the electrical action potential. This review updates the current knowledge about the embryonic origin, development modifications, spatial arrangement, ultrastructural characteristics, and protein profile of the lamellar cells of cutaneous end-organ complexes focusing on Meissner and Pacinian morphotypes.
PubMed: 35356056
DOI: 10.3389/fnins.2022.790130 -
Indian Journal of Otolaryngology and... Dec 2023Neurofibroma is a benign tumor of the peripheral nervous system affecting Schwann cells as well as neural sheath cells. It is usually considered as a component of Von...
Neurofibroma is a benign tumor of the peripheral nervous system affecting Schwann cells as well as neural sheath cells. It is usually considered as a component of Von Recklinghausen's disease, but solitary lesions have also been reported, though not very frequently. It is mostly reported on the skin. In the head and neck region, trigeminal nerve and the cervical nerves are frequently affected; in the oral cavity, tongue is the most commonly affected site. Intra-osseous neurofibromas of the oral cavity are extremely rare and only 22 cases have been reported in the last two decades. The present review is an attempt to know if there is any clinical or radiological feature that can assist in the diagnosis of solitary intra-osseous neurofibroma of the jaws? The literature was reviewed from 01.01.2000 to 05.06.2022 exclusively for case reports, case series, and reviews using the keywords: neurofibroma; neurinoma, maxilla; mandible; jaws, single; solitary; one. Search engines: PubMed Central, Lilac, and Science Direct were used by applying the Boolean operator "OR" and "AND". The review has been submitted for registration in PROSPERO (receipt 340775).
PubMed: 37974811
DOI: 10.1007/s12070-023-04058-9 -
Scientific Reports Dec 2023Recovery after spinal cord injury (SCI) may be propagated by plasticity-enhancing treatments. The myelin-associated nerve outgrowth inhibitor Nogo-A (Reticulon 4, RTN4)... (Meta-Analysis)
Meta-Analysis
Recovery after spinal cord injury (SCI) may be propagated by plasticity-enhancing treatments. The myelin-associated nerve outgrowth inhibitor Nogo-A (Reticulon 4, RTN4) pathway has been shown to restrict neuroaxonal plasticity in experimental SCI models. Early randomized controlled trials are underway to investigate the effect of Nogo-A/Nogo-Receptor (NgR1) pathway blockers. This systematic review and meta-analysis of therapeutic approaches blocking the Nogo-A pathway interrogated the efficacy of functional locomotor recovery after experimental SCI according to a pre-registered study protocol. A total of 51 manuscripts reporting 76 experiments in 1572 animals were identified for meta-analysis. Overall, a neurobehavioral improvement by 18.9% (95% CI 14.5-23.2) was observed. Subgroup analysis (40 experiments, N = 890) revealed SCI-modelling factors associated with outcome variability. Lack of reported randomization and smaller group sizes were associated with larger effect sizes. Delayed treatment start was associated with lower effect sizes. Trim and Fill assessment as well as Egger regression suggested the presence of publication bias. Factoring in theoretically missing studies resulted in a reduced effect size [8.8% (95% CI 2.6-14.9)]. The available data indicates that inhibition of the Nogo-A/NgR1pathway alters functional recovery after SCI in animal studies although substantial differences appear for the applied injury mechanisms and other study details. Mirroring other SCI interventions assessed earlier we identify similar factors associated with outcome heterogeneity.
Topics: Animals; Nogo Proteins; Spinal Cord Injuries; Myelin Sheath; Disease Models, Animal; Nogo Receptors; Spinal Cord; Recovery of Function
PubMed: 38129508
DOI: 10.1038/s41598-023-49260-5 -
Journal of Clinical Neuroscience :... Jun 2024Vestibular schwannomas (VS) are benign tumors arising from vestibular nerve's Schwann cells. Surgical resection via retrosigmoid (RS) or middle fossa (MF) is standard,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vestibular schwannomas (VS) are benign tumors arising from vestibular nerve's Schwann cells. Surgical resection via retrosigmoid (RS) or middle fossa (MF) is standard, but the optimal approach remains debated. This meta-analysis evaluated RS and MF approaches for VS management, emphasizing hearing preservation and Cranial nerve seven (CN VII) outcomes stratified by tumor size.
METHODS
Systematic searches across PubMed, Cochrane, Web of Science, and Embase identified relevant studies. Hearing and CN VII outcomes were gauged using the American Academy of Otolaryngology-Head and Neck Surgery, Gardner Robertson, and House-Brackmann scores.
RESULTS
Among 7228 patients, 56 % underwent RS and 44 % MF. For intracanalicular tumors, MF recorded 38 % hearing loss, compared to RS's 54 %. In small tumors (<1.5 cm), MF showed 41 % hearing loss, contrasting RS's lower 15 %. Medium-sized tumors (1.5 cm-2.9 cm) revealed 68 % hearing loss in MF and 55 % in RS. Large tumors (>3cm) were only reported in RS with a hearing loss rate of 62 %.
CONCLUSION
Conclusively, while MF may be preferable for intracanalicular tumors, RS demonstrated superior hearing preservation for small to medium-sized tumors. This research underlines the significance of stratified outcomes by tumor size, guiding surgical decisions and enhancing patient outcomes.
Topics: Humans; Cranial Fossa, Middle; Facial Nerve; Hearing; Hearing Loss; Neuroma, Acoustic; Neurosurgical Procedures
PubMed: 38615371
DOI: 10.1016/j.jocn.2024.04.007 -
Current Pharmaceutical Design Oct 2021Mammalian nervous systems depend crucially on myelin sheaths covering the axons. In the central nervous system, myelin sheaths consist of lipid structures that are...
Mammalian nervous systems depend crucially on myelin sheaths covering the axons. In the central nervous system, myelin sheaths consist of lipid structures that are generated from the membrane of oligodendrocytes (OL). These sheaths allow fast nerve transmission, protect axons and provide them metabolic support. In response to specific traumas or pathologies, these lipid structures can be destabilized and generate demyelinating lesions. Multiple sclerosis (MS) is an example of a demyelinating disease in which the myelin sheaths surrounding the nerve fibers of the brain and spinal cord are damaged. MS is the leading cause of neurological disability in young adults in many countries, and its incidence has been increasing in recent decades. Related to its etiology, it is known that MS is an autoimmune and inflammatory CNS disease. However, there are no effective treatments for this disease and the immunomodulatory therapies that currently exist have proven limited success since they only delay the progress of the disease. Nowadays, one of the main goals in MS research is to find treatments which allow the recovery of neurological disabilities due to demyelination. To this end, different approaches, such as modulating intracellular signaling or regulating the lipid metabolism of OLs, are being considered. Here, in addition to immunosuppressive or immunomodulatory drugs that reduce the immune response against myelin sheaths, we review a diverse group of drugs that promotes endogenous remyelination in MS patients and their use may be interesting as potential therapeutic agents in MS disease. To this end, we compile specific treatments against MS that are currently in the market with remyelination strategies that have entered into human clinical trials for future reparative MS therapies. The method used in this study is a systematic literature review on PubMed, Web of Science and Science Direct databases up to May 31, 2020. To narrow down the search results in databases, more specific keywords, such as "myelin sheath", "remyelination", "demyelination", "oligodendrocyte" and "lipid synthesis" were used to focus the search. We preferred papers published after January 2015, but did not exclude earlier seminal papers.
Topics: Animals; Humans; Multiple Sclerosis; Myelin Sheath; Oligodendroglia; Pharmaceutical Preparations; Remyelination
PubMed: 33504299
DOI: 10.2174/1381612827666210127121829 -
Journal of Neurosurgery. Spine Jan 2024Malignant melanotic nerve sheath tumors are rare tumors characterized by neoplastic melanin-producing Schwann cells. In this study, the authors report their...
OBJECTIVE
Malignant melanotic nerve sheath tumors are rare tumors characterized by neoplastic melanin-producing Schwann cells. In this study, the authors report their institution's experience in treating spinal and peripheral malignant melanotic nerve sheath tumors and compare their results with the literature.
METHODS
Data were collected from 8 patients who underwent surgical treatment for malignant melanotic nerve sheath tumors between 1996 and 2023 at Mayo Clinic and 63 patients from the literature. Time-to-event analyses were performed for the combined group of 71 cases to evaluate the risk of recurrence, metastasis, and death based on tumor location and type of treatment received. Unpaired 2-sample t-tests and Fisher's exact tests were used to determine statistical significance between groups.
RESULTS
Between 1996 and 2023, 8 patients with malignant melanotic nerve sheath tumors underwent surgery at the authors' institution, while 63 patients were identified in the literature. The authors' patients and those in the literature had the same mean age at diagnosis (43 years). At the authors' institution, 5 patients (63%) experienced metastasis, 6 patients (75%) experienced long-term recurrence, and 5 patients (62.5%) died. In the literature, most patients (60.3%) were males, with a peak incidence between the 4th and 5th decades of life. Nineteen patients (31.1%) were diagnosed with Carney complex. Nerve root tumors accounted for most presentations (n = 39, 61.9%). Moreover, 24 patients (38.1%) had intradural lesions, with 54.2% (n = 13) being intramedullary and 45.8% (n = 11) extramedullary. Most patients underwent gross-total resection (GTR) (n = 41, 66.1%), followed by subtotal resection (STR) (n = 12, 19.4%), STR with radiation therapy (9.7%), and GTR with radiation therapy (4.8%). Sixteen patients (27.6%) experienced metastasis, 23 (39.7%) experienced recurrence, and 13 (22%) died. Kaplan-Meier analyses showed no significant differences among treatment approaches in terms of recurrence-free, metastasis-free, and overall survival (p > 0.05). Similar results were obtained when looking at the differences with respect to intradural versus nerve root location of the tumor (p > 0.05).
CONCLUSIONS
Malignant melanotic nerve sheath tumors are rare tumors with a high potential for malignancy. They carry a dismal prognosis, with a pooled local recurrence rate of 42%, distant metastasis rate of 27%, and mortality rate of 26%. The findings from this study suggest a trend favoring the use of GTR alone or STR with radiation therapy over STR alone. Mortality was similar regardless, which highlights the need for the development of effective treatment options to improve survival in patients with melanotic schwannomas.
Topics: Male; Humans; Adult; Female; Neurofibrosarcoma; Treatment Outcome; Prognosis; Neurosurgical Procedures; Spine; Nerve Sheath Neoplasms
PubMed: 37862711
DOI: 10.3171/2023.8.SPINE23427 -
Acta Neurochirurgica May 2023Systematic review.
STUDY DESIGN
Systematic review.
BACKGROUND
Although degenerative cervical myelopathy (DCM) is the most prevalent spinal cord condition worldwide, the pathophysiology remains poorly understood. Our objective was to evaluate existing histological findings of DCM on cadaveric human spinal cord tissue and explore their consistency with animal models.
METHODS
MEDLINE and Embase were systematically searched (CRD42021281462) for primary research reporting on histological findings of DCM in human cadaveric spinal cord tissue. Data was extracted using a piloted proforma. Risk of bias was assessed using Joanna Briggs Institute critical appraisal tools. Findings were compared to a systematic review of animal models (Ahkter et al. 2020 Front Neurosci 14).
RESULTS
The search yielded 4127 unique records. After abstract and full-text screening, 19 were included in the final analysis, reporting on 150 autopsies (71% male) with an average age at death of 67.3 years. All findings were based on haematoxylin and eosin (H&E) staining. The most commonly reported grey matter findings included neuronal loss and cavity formation. The most commonly reported white matter finding was demyelination. Axon loss, gliosis, necrosis and Schwann cell proliferation were also reported. Findings were consistent amongst cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament. Cavitation was notably more prevalent in human autopsies compared to animal models.
CONCLUSION
Few human spinal cord tissue studies have been performed. Neuronal loss, demyelination and cavitation were common findings. Investigating the biological basis of DCM is a critical research priority. Human spinal cord specimen may be an underutilised but complimentary approach.
Topics: Animals; Humans; Male; Aged; Female; Autopsy; Spinal Cord Diseases; Cervical Vertebrae; Demyelinating Diseases; Cadaver
PubMed: 36820887
DOI: 10.1007/s00701-023-05526-5 -
Revista Brasileira de Psiquiatria (Sao... 2024Evidence from diffusion tensor imaging (DTI) and postmortem studies has demonstrated white-matter (WM) deficits in bipolar disorder (BD). Changes in peripheral blood...
OBJECTIVES
Evidence from diffusion tensor imaging (DTI) and postmortem studies has demonstrated white-matter (WM) deficits in bipolar disorder (BD). Changes in peripheral blood biomarkers have also been observed; however, studies evaluating the potential relationship between brain alterations and the periphery are scarce. The objective of this systematic review is to investigate the relationship between blood-based biomarkers and WM in BD.
METHODS
PubMed, Embase, and PsycINFO were used to conduct literature searches. Cross-sectional or longitudinal studies reporting original data which investigated both a blood-based biomarker and WM (by neuroimaging) in BD were included.
RESULTS
Of 3,750 studies retrieved, 23 were included. Several classes of biomarkers were found to have a significant relationship with WM in BD. These included cytokines and growth factors (interleukin-8 [IL-8], tumor necrosis factor alpha [TNF-a], and insulin-like growth factor binding protein 3 [IGFBP-3]), innate immune system (natural killer cells [NK]), metabolic markers (lipid hydroperoxidase, cholesterol, triglycerides), the kynurenine (Kyn) pathway (5-hydroxyindoleacetic acid, kynurenic acid [Kyna]), and various gene polymorphisms (serotonin-transporter-linked promoter region).
CONCLUSION
This systematic review revealed that blood-based biomarkers are associated with markers of WM deficits observed in BD. Longitudinal studies investigating the potential clinical utility of these specific biomarkers are encouraged.
Topics: Bipolar Disorder; Humans; Biomarkers; White Matter; Myelin Sheath; Cytokines
PubMed: 38712923
DOI: 10.47626/1516-4446-2023-3267 -
Neurosurgery Mar 2020Vestibular schwannomas (VS) are benign tumors derived from Schwann cells ensheathing the vestibulocochlear nerve. The retrosigmoid (RS) surgical approach is useful to...
BACKGROUND
Vestibular schwannomas (VS) are benign tumors derived from Schwann cells ensheathing the vestibulocochlear nerve. The retrosigmoid (RS) surgical approach is useful to resect tumors of multiple sizes while affording the possibility of preserving postoperative hearing.
OBJECTIVE
To conduct a systematic review of published literature investigating hearing preservation rates in patients who underwent the RS approach for VS treatment.
METHODS
The PubMed, Scopus, and Embase databases were surveyed for studies that reported preoperative and postoperative hearing grades on VS patients who underwent RS treatment. Hearing preservation rates were calculated, and additional patient demographic data were extracted. Tumor size data were stratified to compare hearing preservation rates after surgery for intracanalicular, small (0-20 mm), and large (>20 mm) tumors.
RESULTS
Of 383 deduplicated articles, 26 studies (6.8%) met eligibility criteria for a total of 2034 patients with serviceable preoperative hearing, for whom postoperative hearing status was evaluated. Aggregate hearing preservation was 31% and 35% under a fixed and random effects model, respectively. A mixed effects model was used to determine hearing preservation rates depending on tumor size, which were determined to be 57%, 37%, and 12% for intracanalicular, small, and large tumors, respectively. Significant cross-study heterogeneity was found (I2 = 93%, τ2 = .964, P < .01; Q = 287.80, P = < .001), with rates of hearing preservation ranging from 0% to 100%.
CONCLUSION
Tumor size may have an effect on hearing preservation rates, but multiple factors should be considered. Discussion of a patient's expectations for hearing preservation is critical when deciding on VS treatment plans.
Topics: Craniotomy; Hearing; Humans; Neuroma, Acoustic; Postoperative Complications; Postoperative Period; Treatment Outcome
PubMed: 31149722
DOI: 10.1093/neuros/nyz147 -
Annali Italiani Di Chirurgia Jan 2020Ancient Schwannoma is a type of peripheral neurogenic tumor formed by the Schwann cells presenting mainly as a benign and asymptomatic lesion. The neurilemmoma tumor...
Ancient Schwannoma is a type of peripheral neurogenic tumor formed by the Schwann cells presenting mainly as a benign and asymptomatic lesion. The neurilemmoma tumor appears in different sites and, in cases of cervical location, can mimic a carotid body tumor. Herein we describe a clinical case of a 51-year-old woman with latero-cervical swelling. A contrast-enhanced computed tomography scan revealed a classical wineglass image mimicking a carotid body tumor. During surgery the tumor appeared connected to the cervical sympathetic trunk without carotid involvement. The histological exam confirmed the nature of the mass which consisted of an ancient schwannoma. A subsequent systematic review of the literature on ancient schwannoma incidence and treatment confirms it being a benign and rare lesion primarily treatable with open surgery. KEY WORDS: Ancient Schwannoma, Carotid body tumor, Carotid artery, Vascular surgery.
Topics: Carotid Body Tumor; Diagnosis, Differential; Female; Humans; Middle Aged; Neurilemmoma
PubMed: 31957705
DOI: No ID Found