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PubMed1986

A morphometric analysis of the development of the fourth ventricle choroid plexus in the rat.

The choroid plexus from the rat fourth ventricle was investigated at ages from 16 days of gestation to 30 days after birth. Choroid plexus weights were measured and light and electron micrographs were analysed by quantitative stereological techniques at 4 levels of magnification. There was a 10-fold increase in plexus weight between 19 days of gestation and 30 days after birth which was largely due to an increase in epithelial weight, with little change occurring in the connective tissue core. Before birth, epithelial cell height decreased whereas between 10 and 30 days after birth cross-sectional area increased, both events being accompanied by corresponding changes in cell volume. Large intracellular stores of glycogen were present around birth, when they occupied up to 20% of the cell volume. After birth there were significant increases in apical microvillus height, the number of microvilli per cell and in the size of the mitochondria, suggesting that a large increase in choroid plexus secretory function, or the commencement of a new function, occurs after birth in the rat.

Animals↗

PubMed1992

Sodium-dependent nucleoside transport in choroid plexus from rabbit. Evidence for a single transporter for purine and pyrimidine nucleosides.

The overall goal of this study was to determine the mechanisms by which nucleosides are transported in choroid plexus. Choroid plexus tissue slices obtained from rabbit brain were depleted of ATP with 2,4-dinitrophenol. Uridine and thymidine accumulated in the slices against a concentration gradient in the presence of an inwardly directed Na+ gradient. The Na(+)-driven uptake of uridine and thymidine was saturable with Km values of 18.1 +/- 2.0 and 13.0 +/- 2.3 microM and Vmax values of 5.5 +/- 0.3 and 1.0 +/- 0.2 nmol/g/s, respectively. Na(+)-driven uridine uptake was inhibited by naturally occurring ribo- and deoxyribonucleosides (adenosine, cytidine, and thymidine) but not by synthetic nucleoside analogs (dideoxyadenosine, dideoxycytidine, cytidine arabinoside, and 3'-azidothymidine). Both purine (guanosine, inosine, formycin B) and pyrimidine nucleosides (uridine and cytidine) were potent inhibitors of Na(+)-thymidine transport with IC50 values ranging between 5 and 23 microM. Formycin B competitively inhibited Na(+)-thymidine uptake and thymidine trans-stimulated formycin B uptake. These data suggest that both purine and pyrimidine nucleosides are substrates of the same system. The stoichiometric coupling ratios between Na+ and the nucleosides, guanosine, uridine, and thymidine, were 1.87 +/- 0.10, 1.99 +/- 0.35, and 2.07 +/- 0.09, respectively. The system differs from Na(+)-nucleoside co-transport systems in other tissues which are generally selective for either purine or pyrimidine nucleosides and which have stoichiometric ratios of 1. This study represents the first direct demonstration of a unique Na(+)-nucleoside co-transport system in choroid plexus.

Adenosine Triphosphate↗

PubMed1986

Transfer of magnesium across the perfused choroid plexus of sheep.

Isolated perfused choroid plexus preparations from sheep were used to study the effects of low concentrations of magnesium in the perfusion fluid on the transfer of magnesium into choroid plexus fluid (CPF). A perfusion fluid of similar electrolyte composition to sheep blood resulted in CPF similar to ventricular cerebrospinal fluid at a rate of 2.2 microliter min-1 mg-1 dry choroidal tissue. Decreasing the concentration of magnesium in the perfusion fluid caused a fall in the concentration of magnesium in the CPF, although it remained higher than in the perfusion fluid. The rate of transfer of magnesium from the perfusion fluid to the CPF decreased in the presence of high levels of potassium in the perfusion fluid. But decreasing the concentration of calcium in the perfusion fluid had no effect on magnesium transfer rates. These results suggest that the ability of the choroid plexus to transport magnesium against a concentration gradient is an important control of the concentration of the cerebrospinal fluid. However, this ability is insufficient to maintain cerebrospinal fluid concentrations of magnesium at normal levels when the blood magnesium concentration is below about 0.5 mmol l-1.

Animals↗

PubMed1996

P53 expression in choroid plexus neoplasms: an immunohistochemical study.

OBJECTIVE: To evaluate choroid plexus neoplasms for p53 expression. CASE MATERIAL: We studied 10 choroid plexus tumors (four papillomas and six carcinomas) by immunohistochemistry using the DO7 anti-p53 monoclonal antibody. RESULTS: Three of four choroid plexus papillomas demonstrated no staining. Scattered nuclear and rare cytoplasmic positivity was present in one papilloma, which showed foci of increased mitotic activity (labeling index 2.5%). Six of six carcinomas were immunoreactive for p53, and three cases had labeling indexes of over 70%. All immunopositive choroid plexus tumors (7/7) exhibited nuclear staining. Punctate cytoplasmic positivity was identified in 5 of 7 cases. CONCLUSION: Our study suggests that altered p53 expression is detectable by immunohistochemistry in choroid plexus neoplasms and is consistently present in choroid plexus carcinomas.

Adolescent↗

PubMed2005

Changes in E2F5 intracellular localization in mouse and human choroid plexus epithelium with development.

The choroid plexus epithelium (CPe) is a specialized epithelium involved primarily in the production of cerebrospoinal fluid (CSF) which is important for maintaining an optimal homeostatic environment for the brain. Although, the physiology of the CPe is fairly well understood, its development has not been thoroughly studied. It has been recently shown that mice lacking functional transcription factors, E2F5, foxJ1 or p73, develop non-obstructive hydrocephalus likely due to CPe dysfunction. We have further studied their expression in the mouse and human developing CPe, focusing particularly on E2F5. We show here that in the mouse E2F5, foxJ1 and p73 transcripts are detectable as soon as the choroid plexuses form. E2F5 protein is also detected as soon as the choroid plexuses are morphologically apparent both in mouse and human, suggesting that its expression is regulated at the transcriptional level. E2F5 protein is down-regulated late in embryogenesis and this coincides with a change in its intracellular localization, from predominantly nuclear to cytoplasmic. The pattern of expression and intracellular localization of E2F5 in vivo does not appear to correlate with that of proliferating CPe cells, as indicated by protein cell nuclear antigen (PCNA) staining, but rather with their maturation, as changes in E2F5 localization from the nucleus to the cytoplasm parallel the morphological change from pseudostratified to cuboidal epithelium.

Animals↗

PubMed2003

Choroid plexus papilloma of bilateral lateral ventricle.

BACKGROUND: Choroid plexus papillomas are rare, accounting for less than 1% of all intracranial tumours in adults. However, they are relatively more common in childhood and constitute 1.5 to 4% of intracranial tumours. They are most often located in the lateral ventricle, followed by the fourth and third ventricles and, rarely, in the cerebellopontine angle. Bilateral lateral ventricle choroid plexus papilloma is very rare and only a few cases has been reported. CLINICAL PRESENTATION: A 3-year-old boy was admitted to our hospital with a history of irritability and vomiting. Neurological examination on admission was normal. A head computed tomographic scan and magnetic resonance imaging showed tumours in both lateral ventricles, hydrocephalus and a left temporal arachnoid cyst. The bilateral intraventricular mass enhanced densely and homogeneously. A presumptive diagnosis of choroid plexus papillomas was made. INTERPRETATION: The initial surgery was performed for removal of the lesion in the right lateral ventricle, and 20 days later removal of the left lateral ventricle tumour was carried out. Bilateral temporoparietal craniotomy and total removal of tumours was performed. Hydrocephalus was controlled by total tumour resection from both sides. The histology of these tumours was the same and revealed choroid plexus papilloma. Interpretation: Bilateral choroid plexus papilloma is extremely rare and distinct from diffuse villous hypertrophy and their surgical approaches are different from each other. Differential diagnosis should be made by MRI preoperatively. If bilateral choroid plexus papilloma is detected, total surgical resection should be performed. Total surgical removal of the neoplasm not only cures the tumour but also may lead to complete resolution of the hydrocephalus.

Child, Preschool↗

PubMed1997

Choroid plexus carcinoma in an infant.

Choroid plexus carcinoma is a rare tumor and has a strong tendency to spread along the cerebrospinal fluid pathway. The tumor frequently occurs in infants. Radiation therapy is not indicated in infants and the response of this tumor to chemotherapy is variable. Therefore, surgical removal plays a major role in the management of this tumor, especially in infants. A 2-month-old girl with an acute communicating hydrocephalus was presented. Through the left posterior parietal transcortical approach, a choroid plexus carcinoma which had poor demarcation from the posterior thalamus and the medial wall of the lateral ventricle was subtotally (> 95%) removed. Postoperatively a ventriculoperitoneal shunt was inserted. Chemotherapy was refused. Magnetic resonance imaging taken at 11 months after surgery showed multiple intracranial seeding of the tumor. She was in a bed-ridden state. This case revealed the aggressive behaviour of choroid plexus carcinoma in an infant and the dismal result of subtotal removal alone, though it is rather radical.

Choroid Plexus Neoplasms↗

PubMed2004

Giant intracerebral choroid plexus calcification.

While small calcifications of the choroid plexus are frequent, a large, single intracerebral calcification originating from the choroid plexus is rare. This report presents a 27-year-old woman who was admitted because of right temporal headache which had persisted for months. There was no neurological deficit. Computed tomography demonstrated a mass of calcium density measuring approximately 3 x 3 x 4 cm in the right temporal region, extending to the temporal skull base and to the rostral edge of the petrous bone. At surgery a very hard, poorly vascularised tumour originating from the choroid plexus of the temporal horn of the right lateral ventricle was completely removed. Histological workup yielded the diagnosis of a markedly calcified choroid plexus with no indication of neoplasia or inflammation. Physiological intracranial calcifications resulting from local tissue dystrophy are usually incidental. In the case presented here, a large intracerebral choroid plexus calcification was detected in a patient presenting with episodes of severe headache. The potential pathogenetic mechanism is discussed.

Adult↗

PubMed1980

Na,K-, Mg- and HCO3-adenosine triphosphatases in the rabbit brain choroid plexus.

Properties of adenosine triphosphatases (ATPases) in the choroid plexus of rabbit cerebral ventricles were investigated using tissue homogenates and subcellular fractions. Na,K-ATPase or HCO3-ATPase activity of choroid plexus was significantly lower than that of the brain or the kidney, respectively. Among the homogenates of choroid plexus from the lateral, third and fourth ventricles, there were no differences in the activities of Na,K-, Mg- and HCO3-ATPases. In the choroid plexus, Na,K-ATPase activity was demonstrated to be highest in 10,000 X g fraction, while the highest Mg- and HCO3-ATPase activities were observed in 8,000 X g fraction, the so-called mitochondrial fraction. Ion requirement, pH optimum and ouabain sensitivity of Na,K-ATPase in 10,000 X g fraction of choroid plexus were similar to findings in erythrocytes, brain and kidney. However, properties of Mg- and HCO3-ATPases in 8,000 X g fraction were considerably different from those found in the brain and gastric mucosa. In the choroid plexus, thiocyanate ion inhibited Mg-ATPase as well as HCO3-ATPase. These results indicate that characteristics of ATPase systems in the choroid plexus are to some extent different from those in tissues such as brain, kidney and gastric mucosa.

Adenosine Triphosphatases↗

PubMed1976

Quantitative development of choroid plexuses in chick embryo cerebral ventricles.

Quantitative development of choroid plexuses in cerebral ventricles of chick embryos was investigated by means of the planary projection of the choroid plexuses from the time the plexuses reached a consistent flattened structure. Choroid plexuses in the lateral cerbral ventricles were studied from day 6, the plexus in the third cerebral ventricle from day 8, and the plexus in the fourth cerebral ventricle from day 11 of incubation. Regardless of the microscopic origin of these choroid plexuses, their development reached a growth maximum on day 15 of incubation, after which there was a slight regression. The regression was gradual in the plexus of the third cerebral ventricle but a transient enlargement of plexuses in the laternal and in the fourth cerebral ventricle was observed between days 18 and 19. The enlargement of choroid plexuses in the lateral cerebral ventricles was caused by a flattening of the villi, whereas that of the plexus in the fourth cerebral ventricle was caused by thinning and yawning of the villi. The area of choroid plexuses in the lateral cerebral ventricles was six or seven times larger than the sum of the areas of the remaining choroid plexuses.

Animals↗

PubMed1984

Choroid plexus blood flow: evidence for dopaminergic influence.

Choroid plexus blood flow was measured in adult female sheep using the radioactive microsphere technique. The response of choroid plexus, renal and cortical blood flow to the infusion of dopamine (11 sheep), haloperidol (7 sheep) and propranolol (6 sheep) were compared. Choroid plexus and renal blood flow significantly increased after dopamine infusion (55% and 49% respectively). Choroid plexus and renal blood flow decreased significantly following haloperidol infusion (-24% and 29% respectively). Cortical blood flow did not significantly change. Propranolol infusion did not significantly change blood flow in these regions. These observations suggest that dopaminergic mechanisms play a role in the regulation of choroid plexus as well as renal blood flow.

Animals↗

PubMed1974

Active transport of sodium and potassium by the choroid plexus of the rat.

1. Choroid plexus from the lateral ventricle in the adult rat was found to contain approximately 54 m-equiv Na(+) and 89 m-equiv K(+) per kg wet tissue.2. The total water (79%), the extracellular space (21%) and the red blood cell volume (8-9%) in choroid plexus were quantified separately by analysing the distribution of [(14)C]antipyrine, [(14)C]inulin and (51)Cr-tagged erythrocytes, respectively, between this tissue and plasma water.3. The tissue electrolyte data together with the compartmental (space) data were used to calculate an average concentration of Na(+) (39 m-equiv/kg cell H(2)O) and of K(+) (144) in the choroid cell.4. Under various experimental conditions known to stimulate or inhibit the Na(+)-K(+) transport system in other tissues, there were significant changes (10-40 m-equiv/kg cell H(2)O) in the concentrations of both these cations in the plexus epithelial cells.5. Choroid cell K(+) was not independent of the concentration of K(+) in plasma since substantial fluctuations in cell K(+) occurred in rats rendered either hypo- or hyperkalaemic; also, the choroid cell apparently cannot maintain a constant gradient between itself and c.s.f. in the face of kalaemic disturbances.6. Evidence is offered to support the hypothesis that the choroid plexus of the lateral ventricle has a Na(+)-K(+) pump, the operation of which contributes to the maintenance of K(+) homoeostasis in the C.N.S.

Animals↗

PubMed1989

Pediatric choroid plexus neoplasms: MR, CT, and pathologic correlation.

Choroid plexus papillomas are rare, constituting approximately 0.5% of all intracranial neoplasms. Four benign choroid plexus papillomas and one choroid plexus carcinoma were retrospectively reviewed in patients aged 4-20 months who had been examined with magnetic resonance (MR) imaging with a field strength of 0.5 T or 1.0 T and with computed tomography (CT) before and after the administration of contrast material. In general, the tumors were of intermediate signal intensity on T1-weighted images and of either intermediate or increased signal intensity (T2 lengthening) with T2 weighting. All demonstrated variable areas of internal signal void interpreted as signifying regional blood flow, calcification, or old hemorrhage. CT findings included relatively uniform contrast enhancement. Microscopic pathologic changes of the benign lesions mimicked the appearance of normal choroid plexus and confirmed the highly vascular nature of these tumors. MR imaging, with its high-resolution multiplanar techniques, offers direct visualization of these lesions in relation to normal anatomy and better discrimination and confirmation of their intraventricular location, facilitating surgery and postoperative follow-up.

Carcinoma↗

PubMed2005

Intramedullary ectopic choroid plexus: report of a rare case.

OBJECTIVE AND IMPORTANCE: Intracranial cysts containing an ectopic choroid plexus or choroid plexus-like tissue have seldom been described in the literature. However, there has been no report of a spinal intramedullary cyst containing an ectopic choroid plexus. This is the first case report in the available literature of an ectopic choroid plexus tissue in the spinal cord. CLINICAL PRESENTATION: A 30-year-old man presented with complaints of progressive descending weakness of both upper limbs and increasing stiffness of the lower limbs along with numbness of all four limbs without a history of any bowel or bladder disturbances. Examination was suggestive of a C5-T2 intramedullary lesion. Magnetic resonance imaging revealed a C6-T2 intramedullary cystic lesion along with a small anterosuperiorly placed lesion enhancing with contrast. INTERVENTION: A C6-T2 laminotomy and exploration of the intramedullary cyst and gross total microsurgical excision of the reddish vascular frond-like structure resembling the choroid plexus were performed along with a syringostomy. A laminoplasty with miniplates and screws was performed. Histopathological and immunohistochemical studies revealed a normal choroid plexus. The patient has been followed for 1 year and has demonstrated symptomatic improvement. CONCLUSION: Although there have been rare case reports of drop metastasis of choroid plexus papillomas in the spine, this is the first case report in the available literature of normal but ectopic choroid plexus tissue in the spinal cord.

Adult↗

PubMed1992

Immunohistochemical evidence of endothelin-1 in human choroid plexus.

An immunohistochemical investigation was carried out on 17 specimens of human choroid plexus obtained post mortem, 1 biopsy of normal choroid plexus including part of the lateral ventricle and 1 papilloma of the choroid plexus removed surgically. The material was fixed in formalin. Paraffin and cryostat sections were used. A polyclonal antiserum to endothelin-1 served as a primary antibody. The avidin-biotin-peroxidase method was applied to demonstrate the immunoreaction. The epithelial cells of the choroid plexuses, the choroid papilloma and most ependymal cells of the lateral ventricle showed a distinct brown reaction product in their cytoplasm indicating antigenic sites to endothelin-1. The reaction was of lesser intensity in the ependymal cells. The connective tissue in choroid plexus was unstained. A positive immunoreaction was present in the walls of some vessels in the choroid plexus in cryostat sections. This is the first report on the presence of antigenic sites to endothelin-1 in the epithelial cells of the human choroid plexus. The role of endothelin in these cells should be investigated to ascertain if the cells synthesize this biologically active peptide or if it is merely bound to receptors in them.

Adult↗

PubMed1994

Chromosome aberrations in choroid plexus papillomas.

Karyotypic data on choroid plexus papillomas are scarce and, to date, have revealed no consistent aberrations. We karyotyped a choroid plexus papilloma which was characterized by a stemline of 52,XX, + 7, + 11, + 12, + 12, + 15, + 18. Additional copies of chromosomes 16, 17, and 20 were also observed in a significant proportion of the metaphase cells analyzed. Based upon this index case, we retrospectively analyzed eight additional choroid plexus papillomas by fluorescence in situ hybridization by using pericentromeric probes to chromosomes 7, 11, 12, 15, 16, 17, 18, and 20. Extra hybridization signals were observed in five of the eight cases examined. All five cases had extra signals with the chromosome 7 probe, four cases had extra signals with the chromosome 12 probe, and three cases had extra signals with the chromosome 15, 17, and 18 probes. The overall DNA content of these same cases (as determined by image analysis) suggests that gains of additional chromosomes other than those examined may be present.

Adolescent↗

PubMed1992

Effect of arginine vasopressin on blood vessels of the perfused choroid plexus of the sheep.

The perfused sheep choroid plexus was used to evaluate the response of the plexus blood vessels to systemically administered arginine vasopressin (AVP). AVP was found to decrease the diameter of the choroid plexus arterioles with a maximum change of 28 +/- 5% (mean +/- S.E.) at a plasma peptide concentration of 10(-7) M. This effect was blocked by the specific V1-vasopressinergic antagonist, d(CH2)5Tyr(Me)AVP. In contrast, venules were found not to show any appreciable response to AVP. Plasma AVP concentrations necessary to evoke a significant response of the choroid plexus arterioles are much higher than the highest plasma peptide levels observed in different physiological or pathophysiological situations. Some indirect evidence suggests, however, that AVP might be released within the choroid plexus from the vasopressinergic synaptic terminals, thus reaching a considerably high local concentration. It is possible then that the plexus vessels' tone could be controlled by the putative vasopressinergic neuronal fibers ending in the choroid plexus.

Animals↗

PubMed1995

Differential expression of cell adhesion molecules (CAM), neural CAM and epithelial cadherin in ependymomas and choroid plexus tumors.

A series of frozen specimens of 18 ependymomas and 7 choroid plexus tumors were examined for their expression of cell adhesion molecules, such as neural cell adhesion molecule (NCAM), its polysialylated isoforms (PSA NCAM), and epithelial (E-) cadherin, and of intermediate filament proteins, such as glial fibrillary acidic protein (GFAP) and cytokeratin, using various monoclonal and polyclonal antibodies. Normal choroid plexus and ependyma were taken as controls. Anti-E-cadherin immunoreactivity was observed on the basolateral part of most adult choroid plexus and benign choroid plexus papilloma cells. However, a small number of atypical papillomas and carcinoma cells showed anti- E-cadherin immunoreactivity throughout their cell surface membrane. NCAM were not expressed by adult choroid plexus and benign papilloma cells. Only a few cells expressed NCAM and PSA NCAM in developing choroid plexus, atypical papillomas and carcinomas. Cytokeratin expression was always observed in choroid plexus and their tumors; GFAP expression was variable from case to case. In contrast, ependymal cells and their tumors never expressed E-cadherin but strongly expressed NCAM. PSA NCAM was found in ependymomas exhibiting anaplastic features. All ependymomas strongly expressed GFAP and a few demonstrated slight expression of cytokeratin. These data suggest that, besides GFAP and cytokeratin, NCAM and E-cadherin are of potential diagnostic value in distinguishing choroid plexus tumors from ependymomas. E-cadherin and NCAM may play a role in the functional organization of normal choroid plexus and ependyma, respectively. In particular, incomplete or irregular anti-E-cadherin expression in choroid plexus tumors and PSA NCAM immunoreativity in ependymomas and choroid plexus tumors correlates with the emergence of anaplastic histological features.

Adolescent↗