-
BioRxiv : the Preprint Server For... Aug 2023The recent characterization of the glymphatic system and meningeal lymphatics has re-emphasized the role of the meninges in facilitating CSF transport and clearance....
BACKGROUND
The recent characterization of the glymphatic system and meningeal lymphatics has re-emphasized the role of the meninges in facilitating CSF transport and clearance. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles.
METHODS
1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 minutes post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 hours post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also performed.
RESULTS
There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the dura mater of the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH.
CONCLUSIONS
Differential CSF tracer handling by the leptomeninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border.
PubMed: 37645776
DOI: 10.1101/2023.08.10.552826 -
PeerJ 2023Chronic subdural hemorrhage (CSDH) refers to a hematoma with an envelope between the dura mater and the arachnoid membrane and is more common among the elderly. It was...
Chronic subdural hemorrhage (CSDH) refers to a hematoma with an envelope between the dura mater and the arachnoid membrane and is more common among the elderly. It was reported that the dura mater, which is highly vascularized with capillary beds, precapillary arterioles and postcapillary venules play an important role in the protection of the central nervous system (CNS). Numerous evidences suggests that peptides play an important role in neuroprotection of CNS. However, whether dura mater derived endogenous peptides participate in the pathogenesis of CSDH remains undetermined. In the current study, the peptidomic profiles were performed in human dura of CSDH (three patients) and the relative control group (three non-CSDH samples) by LC-MS (liquid chromatography-mass spectrometry). The results suggested that a total of 569 peptides were differentially expressed in the dura matter of CSDH compared with relative controls, including 217 up-regulated peptides and 352 down-regulated peptides. Gene Ontology (GO) analysis demonstrated that the precursor proteins of those differentially expressed peptides were involved in the various biological processes. Interestingly, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that NETs participated in the pathogenies of CSDH. Further investigate showed that H3Cit was significantly elevated in the dural and hematoma membranes of patients with CSDH compared to patients without CSDH. Taken together, our results showed the differentially expressed peptides in human dura mater of CSDH and demonstrated that NETs formation in the dural and hematoma membranes might be involved in the pathogenesis of CSDH. It is worth noting that pharmacological inhibition of NETs may have potential therapeutic implications for CSDH.
Topics: Humans; Aged; Extracellular Traps; Hematoma, Subdural, Chronic; Dura Mater; Peptides; Proteomics
PubMed: 38144176
DOI: 10.7717/peerj.16676 -
Animals : An Open Access Journal From... Feb 2024Meningitis is the inflammation of the membranes surrounding the central nervous system and is poorly described in water buffaloes. Five cases of meningitis in adults...
Meningitis is the inflammation of the membranes surrounding the central nervous system and is poorly described in water buffaloes. Five cases of meningitis in adults buffaloes of the Murrah and Mediterranean breads were studied. All buffaloes came from a farm located in the municipality of Castanhal, Pará, Brazil at different times. Clinical examination showed neurological clinical signs, such as apathy, reluctance to move, spastic paresis especially of the pelvic limbs, hypermetria, difficulty getting up, pressing of the head into obstacles and convulsion. In three buffaloes, a large part of the horn had been lost, exposing the corresponding frontal sinus, through which a bloody to purulent exudate flowed. The hemogram revealed neutrophilic leukocytosis. At necropsy, adherence of the dura mater to the periosteum and a purulent to fibrinopurulent exudate were observed in the sulci of the cerebral cortex and on the pia mater over almost the entire surface of the brain and throughout the spinal cord. The cerebrospinal fluid had a cloudy aspect with fibrin filaments. The histopathology of buffaloes confirmed the diagnosis of bacterial fibrinopurulent meningitis. Buffaloes are susceptible to bacterial inflammation of the meninges due to fractures of the base of the horn and mostly present with neurological manifestations.
PubMed: 38338148
DOI: 10.3390/ani14030505 -
Scientific Reports Aug 2023Myodural bridge (MDB) is a dense connective tissue between suboccipital muscle and dura mater. However, there are few reports on the development and maturation of the...
Myodural bridge (MDB) is a dense connective tissue between suboccipital muscle and dura mater. However, there are few reports on the development and maturation of the human MDB. This study aims to explore the developmental relationship between suboccipital muscle and MDB. 30 head and neck specimens from human fetuses (F) ranging from the 12th to 41st week (W) were made into histological sections. The F12W sections showed evidence that the dura mater dominated by fibroblasts, attached to the posterior atlanto-axial membrane (PAAM) which completely sealed the atlanto-axial space. In the F13W stage, myofibrils of the suboccipital muscle fibers increased significantly in number. At the F14W stage, a gap was observed at the caudal end of the PAAM. Numerous myodural bridge-like structures were observed blending into the dura mater through the gap. At the F19W stage, muscle cells mature. Starting at the F21W stage, the MDB were observed as fibroblasts that cross the atlanto-axial interspace and attach to the dura mater. Therefore, the traction generated by the suboccipital muscles seems to promote the maturity of MDB. This study will provide new morphological knowledge to support future research on the function of the human MDB and regulating the development mechanism of MDB.
Topics: Humans; Dura Mater; Fibroblasts; Head; Muscle Fibers, Skeletal; Fetus
PubMed: 37591924
DOI: 10.1038/s41598-023-40709-1 -
Annals of Medicine and Surgery (2012) Nov 2023Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system...
INTRODUCTION AND IMPORTANCE
Acalvaria is a rare congenital malformation in which the flat bones of the cranial vault, dura mater, and associated muscles are absent while the central nervous system usually remains unaffected. It is an extremely rare congenital anomaly with only a handful of cases being reported in literature.
CASE PRESENTATION
The authors report a case of a 2-month-old male infant with acalvaria who was delivered at home and brought to our centre with the complaint of an abnormally soft skull. He was evaluated in a primary centre in rural Nepal. Parietal bones were missing bilaterally but no other abnormalities were found during the physical examination and investigations. Major differential diagnoses like anencephaly, cephalocele, osteogenesis imperfecta type II, and hypophosphatasia were ruled out with the help of history, physical examination, and available investigations and the case was diagnosed as acalvaria.
CLINICAL DISCUSSION
Acalvaria is a post-neurulation defect which is associated with anomalies of various organ systems. Radiological diagnosis, with supportive laboratory investigations, is the most reliable method of antenatal diagnosis.
CONCLUSION
Acalvaria is known to have a dismal prognosis and all the living cases with long-term follow-up are mentally retarded and physically disabled. Early and reliable antenatal diagnosis can reduce the economic, physical, and psychological burden associated with this fatal disease, especially in low-income countries.
PubMed: 37915700
DOI: 10.1097/MS9.0000000000001339 -
The Journal of Headache and Pain Jan 2024Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) are effective in the prevention of chronic and frequent episodic migraine....
BACKGROUND
Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) are effective in the prevention of chronic and frequent episodic migraine. Since the antibodies do not cross the blood brain barrier, their antinociceptive effect is attributed to effects in meningeal tissues. We aimed to probe if such an antibody can be visualized within the dura mater and the trigeminal ganglia following its administration to rats and to examine if the activity of the trigeminovascular nocisensor complex is influenced by this treatment.
METHODS
Effects of the anti-CGRP antibody galcanezumab on the trigeminovascular nocisensor complex was examined by measuring release of sensory neuropeptides and histamine from the rat dura mater. Deposits of galcanezumab were visualized by fluorescence microscopy in the trigeminal ganglion and the dura mater.
RESULTS
Fluorophore-labelled galcanezumab was detected in the dura mater and the trigeminal ganglion up to 30 days after treatment affirming the long-lasting modulatory effect of this antibody. In female rats, seven days after systemic treatment with galcanezumab the capsaicin-induced release of CGRP was decreased, while that of substance P (SP) was increased in the dura mater. In control rats, release of the inhibitory neuropeptide somatostatin (SOM) was higher in females than in males. Stimulation with high concentration of KCl did not significantly change the release of SOM in control animals, while in rats treated with galcanezumab SOM release was slightly reduced. Galcanezumab treatment also reduced the amount of histamine released from dural mast cells upon stimulation with CGRP, while the effect of compound 48/80 on histamine release was not changed.
CONCLUSIONS
Galcanezumab treatment is followed by multiple changes in the release of neuropeptides and histamine in the trigeminal nocisensor complex, which may contribute to the migraine preventing effect of anti-CGRP antibodies. These changes affecting the communication between the components of the trigeminal nocisensor complex may reduce pain susceptibility in migraine patients treated with CGRP targeting monoclonal antibodies.
Topics: Humans; Male; Rats; Female; Animals; Calcitonin Gene-Related Peptide; Histamine; Dura Mater; Migraine Disorders; Trigeminal Ganglion; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized
PubMed: 38243174
DOI: 10.1186/s10194-024-01717-2 -
Brain Research Bulletin Apr 2024The central nervous system (CNS) has been considered an immunologically privileged site. In the past few decades, research on inflammation in CNS diseases has mostly... (Review)
Review
The central nervous system (CNS) has been considered an immunologically privileged site. In the past few decades, research on inflammation in CNS diseases has mostly focused on microglia, innate immune cells that respond rapidly to injury and infection to maintain CNS homeostasis. Discoveries of lymphatic vessels within the dura mater and peripheral immune cells in the meningeal layer indicate that the peripheral immune system can monitor and intervene in the CNS. This review summarizes recent advances in the involvement of T lymphocytes in multiple CNS diseases, including brain injury, neurodegenerative diseases, and psychiatric disorders. It emphasizes that a deep understanding of the pathogenesis of CNS diseases requires intimate knowledge of T lymphocytes. Aiming to promote a better understanding of the relationship between the immune system and CNS and facilitate the development of therapeutic strategies targeting T lymphocytes in neurological diseases.
Topics: Humans; T-Lymphocytes; Central Nervous System; Central Nervous System Diseases; Microglia; Mental Disorders
PubMed: 38387531
DOI: 10.1016/j.brainresbull.2024.110904 -
Journal of Tissue Engineering 2024The dura mater, as the crucial outermost protective layer of the meninges, plays a vital role in safeguarding the underlying brain tissue. Neurosurgeons face significant... (Review)
Review
The dura mater, as the crucial outermost protective layer of the meninges, plays a vital role in safeguarding the underlying brain tissue. Neurosurgeons face significant challenges in dealing with trauma or large defects in the dura mater, as they must address the potential complications, such as wound infections, pseudomeningocele formation, cerebrospinal fluid leakage, and cerebral herniation. Therefore, the development of dural substitutes for repairing or reconstructing the damaged dura mater holds clinical significance. In this review we highlight the progress in the development of dural substitutes, encompassing autologous, allogeneic, and xenogeneic replacements, as well as the polymeric-based dural substitutes fabricated through various scaffolding techniques. In particular, we explore the development of composite materials that exhibit improved physical and biological properties for advanced dural substitutes. Furthermore, we address the challenges and prospects associated with developing clinically relevant alternatives to the dura mater.
PubMed: 38343772
DOI: 10.1177/20417314241228118