Psammoma bodies – Friends or foes of the aging choroid plexus

E-Cadherin Is Expressed in Epithelial Cells of the Choroid Plexus in Human and Mouse Brains

Evidence showing the functional significance of the choroid plexus is accumulating. Epithelial cells with tight and adherens junctions of the choroid plexus play important roles in cerebrospinal fluid production and circadian rhythm formation. Although specific types of cadherin expressed in adherens junctions of choroid plexus epithelium (CPE) have been examined, they remained uncertain. Recent mass spectrometry and immunolocalization analysis revealed that non-epithelial cadherins, P- and N-cadherins, are expressed in the lateral membrane of CPE, whereas E-cadherin expression has not been confirmed in CPE of humans or mice. In this study, we examined E-cadherin expression in CPE of mice and humans by RT-PCR, immunohistochemical-, and Western blotting analyses. We confirmed, by using RT-PCR analysis, the mRNA expression of E-cadherin in the choroid plexus of mice. The immunohistochemical expression of E-cadherin was noted in the lateral membrane of CPE of mice and humans. We further confirmed, in Western blotting, the specific immunoreactivity for E-cadherin. Immunohistochemically, the expression of E- and N-cadherins or vimentin was unevenly distributed in some CPE, whereas that of E- and P-cadherins or β-catenin frequently co-existed in other CPE. These findings indicate that E-cadherin is expressed in the lateral membrane of CPE, possibly correlated with the expression of other cadherins and cytoplasmic proteins.

Onchocerciasis-associated epilepsy: an update and future perspectives

Onchocerciasis-associated epilepsy (OAE) is an important neglected public health problem in areas with high ongoing onchocerciasis transmission. The risk that children in such areas develop epilepsy is related to their Onchocerca volvulus microfilarial (mf) load. Before the implementation of mass treatment with ivermectin, microfilariae were detected in cerebrospinal fluid (CSF). More recently, neither O. volvulus microfilariae nor DNA were detected in CSF or brain tissue; however, these samples were obtained years after seizure onset. It is possible that during fever-induced increased blood-brain barrier permeability, microfilariae enter the brain and, upon dying, cause an inflammatory reaction inducing seizures. Including OAE in the onchocerciasis disease burden estimation may mobilise extra resources for onchocerciasis disease elimination and treatment/care of OAE-affected persons/families.

Immunohistochemical expression of osteopontin and collagens in choroid plexus of human brains

Evidence showing the functional significance of the choroid plexus is accumulating. Although it is clinically well‐known that calcification is frequently seen in the choroid plexus of aged human brains, it is unclear why calcification occurs in the aged choroid plexus and what exert effects on the calcification has. In this study, immunohistochemical localizations of collagens and other molecules related to fibrosis or calcification were investigated on the choroid plexus of autopsied human brains. Densely fibrous or calcified materials were located in the stroma just below the epithelial cells of the choroid plexus of all human brains examined. Immunoreactivity for collagen type I was identified in the stroma just below the epithelial cells, consistent with the densely fibrous or calcified area, whereas that for collagen type III was observed in almost all stroma other than the densely fibrous or calcified areas. Linear or membranous immunoreactivity for collagen type IV was intermittently localized on the epithelium‐facing side of the materials, suggesting an injured basement membrane. In addition, clear immunoreactivity for osteopontin was localized on the epithelium‐facing side of the fibrous or calcified materials as well as in the cytoplasm of epithelial cells. These findings indicate that collagen type I exists in contact with osteopontin in and around the densely fibrous or calcified materials in the choroid plexus. They suggest that the densely fibrous or calcified materials are deposited in the subepithelial stroma just below an injured basement membrane of epithelial cells via the collagen type I and osteopontin.

Physiological and Pathological Factors Affecting Drug Delivery to the Brain by Nanoparticles

The prevalence of neurological/neurodegenerative diseases, such as Alzheimer's disease is known to be increasing due to an aging population and is anticipated to further grow in the decades ahead. The treatment of brain diseases is challenging partly due to the inaccessibility of therapeutic agents to the brain. An increasingly important observation is that the physiology of the brain alters during many brain diseases, and aging adds even more to the complexity of the disease. There is a notion that the permeability of the blood-brain barrier (BBB) increases with aging or disease, however, the body has a defense mechanism that still retains the separation of the brain from harmful chemicals in the blood. This makes drug delivery to the diseased brain, even more challenging and complex task. Here, the physiological changes to the diseased brain and aged brain are covered in the context of drug delivery to the brain using nanoparticles. Also, recent and novel approaches are discussed for the delivery of therapeutic agents to the diseased brain using nanoparticle based or magnetic resonance imaging guided systems. Furthermore, the complement activation, toxicity, and immunogenicity of brain targeting nanoparticles as well as novel in vitro BBB models are discussed.

First definition of burned choroid plexus in acidic cerebrospinal fluid-filled brain ventricles during subarachnoid hemorrhage: Experimental study

Blood and cerebrospinal fluid (CSF) acidosis is the most troubling complication in subarachnoid hemorrhage (SAH) if carotid body (CB) networks are disrupted. However, histopathological examination of the choroid plexus (CP) in acidic CSF has not been evaluated so far. In this study, we aimed to investigate the CP in acidic CSF following SAH. Twenty-eight rabbits were used. Five rabbits were used to analyze CB network (control group; n = 5); seven rabbits were injected 1 mL of saline (Sham group; n = 7); and the rest 16 rabbits were given 1 mL of autologous arterial blood inject into the cisterna magna to create SAH (SAH group; n = 16). Blood and CSF pH values were recorded before/during/after the experimental procedures. Nuclear darkening, cellular shrinkage and pyknosis suggested the presence of apoptosis of epithelial cells of CP. The densities of normal and degenerated epithelial cells of CPs were estimated using stereological methods. The relationship between the pH values and degenerated epithelial cell densities of CPs were statistically compared by Mann-Whitney U-test. The pH values of blood were estimated as 7.359 ± 0.039 in the control group, 7.318 ± 0.062 in the Sham group, 7.23 ± 0.013 in the SAH group. CSF pH values were 7.313 ± 0.028 in the control group, 7.296 ± 0.045 in the Sham group, and 7.224 ± 0.012 in the SAH group. Degenerated epithelial cell density of CP was 25 ± 7 in the control group, 226 ± 64 in the Sham group, and 2115 ± 635 in the SAH group. There was a considerable link between CSF pH values and degenerated epithelial cells of CP (P < 0.0001). This study shows that CB insult causes acidosis of CSF as well as cellular degeneration of CP during SAH. This is the first description of this in the literature.

Chronic encapsulated intraventricular hematoma in a pediatric patient: case report

Chronic encapsulated intraventricular hematoma (CEIVH) is a rare, intraventricular, nonneoplastic mass lesion that can become symptomatic from mass effect or obstructive hydrocephalus. Only 5 cases have been reported in the literature, and only one of these occurred in a pediatric patient and dates back to the pre-modern neuroimaging and pre-microsurgical era of neurosurgery. Imaging features can mimic those of many more common intraventricular lesions, such as choroid plexus tumors or cavernous malformations. In all reported symptomatic cases, resection was safely performed and led to a cure and symptom resolution. Here, the authors present a case of CEIVH in a pediatric patient, describe the operative techniques of resection, review the available literature, and discuss current understanding of the pathophysiology, making this the most comprehensive report on this disease entity to date. The case is a 14-year-old boy who presented with headaches and emesis. Computed tomography showed a hyperdense mass in the trigone of the right lateral ventricle. Magnetic resonance imaging showed a contrast-enhancing well-circumscribed mass. Right temporal craniotomy utilizing a posterior middle temporal gyrus transcortical approach was performed, and gross-total resection was achieved. Pathology revealed a CEIVH. The boy's postoperative course was uncomplicated, and he was discharged 2 days after surgery.

Psammomatous Cavernous Malformation Presenting as Drug-Resistant Epilepsy: Case Illustration and Review of Literature

BACKGROUND

Psammoma bodies (PBs) are whorled, laminated hyaline spherules containing calcium deposits. Intracranially, the presence of PBs is associated with variants of meningioma and pituitary lesions, as well as aging choroid plexus. Limited information exists on their presence in vascular malformation.

RESULTS

In this report, we describe a case of an adolescent male with drug-resistant epilepsy that was surgically managed at our regional epilepsy center. The epileptogenic focus was determined to be emanating from an indolent right insular lesion. Histopathologic evaluation showed the abundance of intravascular and perivascular PBs. Immunohistochemical evaluation confirmed the vascular origin using vascular markers. The unusual presence of PBs in a vascular lesion was unanticipated.

CONCLUSIONS

Based on our case, we present the clinicoradiologic characteristics, supplemented with intraoperative findings, for this unusual lesion. In addition, because of the unusual presence of PBs in vascular lesions, we provide the findings of a systematic literature review to show the association of PBs with intracranial vascular lesions.

Serum fetuin-A levels in subjects with and without choroid plexus calcification

Choroid plexus is an intraventricular plexus of tissue which is responsible for secretion of cerebrospinal fluid. Calcification of choroid plexus is found to be associated with age and gender. One of novel and popular glycoprotein that involves in inhibition of mineralization is human fetuin-A. In our study, we investigated plasma levels of fetuin-A in subjects with and without choroid plexus calcification. For this purpose, 41 subjects with choroid plexus calcification and 41 age and gender matched subjects with normal appearing choroid plexus were recruited. Calcified and normal choroid plexus tissue identified on computed tomography images. Overnight fasting venous blood samples were collected to measure serum fetuin-A levels using a human fetuin-A enzyme-linked immunosorbent assay kit. Statistically significant difference concerning the median concentration of fetuin-A was found between subjects with and without choroid plexus calcification (p: 0.040). Significance was also present between male subgroups (p: 0.017) and 18-27 years age subgroups (p: 0.025). Our results suggest that fetuin-A has an potent role in calcification process of choroid plexus.

Dysregulated iron metabolism in the choroid plexus in fragile X-associated tremor/ataxia syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with premutation alleles of the FMR1 gene that is characterized by progressive action tremor, gait ataxia, and cognitive decline. Recent studies of mitochondrial dysfunction in FXTAS have suggested that iron dysregulation may be one component of disease pathogenesis. We tested the hypothesis that iron dysregulation is part of the pathogenic process in FXTAS. We analyzed postmortem choroid plexus from FXTAS and control subjects, and found that in FXTAS iron accumulated in the stroma, transferrin levels were decreased in the epithelial cells, and transferrin receptor 1 distribution was shifted from the basolateral membrane (control) to a predominantly intracellular location (FXTAS). In addition, ferroportin and ceruloplasmin were markedly decreased within the epithelial cells. These alterations have implications not only for understanding the pathophysiology of FXTAS, but also for the development of new clinical treatments that may incorporate selective iron chelation.

Crush cytology of a primary intraspinal rhabdoid papillary meningioma: a case report

BACKGROUND

Both rhabdoid and papillary meningioma are rare variants of meningioma categorized as WHO grade III. Here, we report a rare case of combined rhabdoid papillary meningioma with discussion of its differential intraoperative cytologic diagnoses.

CASE

The patient was a 72-year-old female who presented with a huge mass at the cervical spine on MRI. The crush smears showed a radially arranged pattern of elongated tumor cells centered around the vessels, which formed a pseudorosette-like papillary structure, as well as singly scattered large gemistocyte-like rhabdoid cells with distinct cell borders. Rhabdoid cells had eccentrically placed vesicular nuclei with plump, fibrillary-to-hyaline cytoplasm with short broad processes. Nuclei had occasional nuclear inclusions with no nuclear grooves.

CONCLUSION

Rhabdoid papillary meningiomas, encountered less often, should be distinguished from metastatic tumors of rhabdoid or papillary configuration, astrocytomas, ependymomas and atypical teratoid/rhabdoid tumor. Search for eosinophilic hyaline cytoplasm, rather than a fibrillary one, is critical for distinguishing it from other commonly encountered spinal cord tumors in the total absence of meningothelial whorls, like the present case. We also emphasize that the present case is the first case of rhabdoid papillary meningioma with primary manifestation in the spinal cord.

Arachnoid granulations of the temporal bone: a histologic study of dural and osseous penetration

HYPOTHESIS

Arachnoid granulations (AG) are more prevalent along the middle fossa surface of the temporal bone, where they produce larger bony defects than those occurring on the posterior surface.

BACKGROUND

Dural and bony defects formed by AGs are proposed to lead to spontaneous meningoencephaloceles and cerebrospinal fluid otorrhea. They most commonly occur at the tegmen and in individuals older than 40 years.

METHODS

Vertically sectioned temporal bones were evaluated using light microscopy to determine AG histology, distribution, and morphometry and to determine the prevalence of AG penetration in the donor population.

RESULTS

AGs were observed to penetrate the dura mater and make direct contact with cortical surfaces in 12.7% of donors in the Johns Hopkins Temporal Bone Collection. AGs occurred at middle fossa sites 13% more frequently than at posterior fossa sites. At middle fossa sites AGs produced significantly larger bony openings and were more likely to be associated with herniating brain tissue. Donors with AGs were significantly older, and all were in the late 30s or older.

CONCLUSION

Erosion of the temporal bone by AGs is not a rare occurrence in the population and becomes increasingly prevalent with age. It is estimated that 14 in 1,000 donors were at greatest risk of eventual cerebrospinal fluid leakage at the tegmen. The age and anatomic distribution described in this study strengthens the notion that AG penetration plays a role in the pathophysiology of spontaneous cerebrospinal fluid leaks and meningoencephaloceles of the temporal bone.