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Na+-dependent gamma-aminobutyric acid (GABA) transport in the choroid plexus of rabbit.

The goal of this study was to examine the mechanisms of transport of gamma-aminobutyric acid (GABA) in the choroid plexus. Choroid plexus slices from the rabbit were depleted of ATP with 2,4-dinitrophenol. GABA accumulated in the choroid plexus slices in a concentrative manner in the presence of an inwardly-directed Na+ gradient. Uptake occurred in the presence of Cl-; replacement of Cl- with gluconate abolished uptake. SCN-, NO3- or Br- were able to support uptake in the absence of Cl- to a significant extent (80, 68 and 61% of control, respectively). GABA uptake was saturable (Km of 37 +/- 8.5 microM, Vmax of 409 +/- 43 nmol/g/min). Na+-driven GABA uptake was inhibited by beta-alanine (IC50 = 22.9 microM) and hypotaurine (IC50 = 21.9 microM) but less potently by nipecotic acid (IC50 = 244 microM) and hydroxy-nipecotic acid (IC50 = 284 microM). Betaine, L-(2,4)-diaminobutyric acid, guvacine and 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol were weak inhibitors (IC50 > 500 microM). GABA inhibited Na+-driven uptake of taurine (IC50 = 230 microM); taurine, however, did not inhibit GABA uptake (IC50 > 1 mM). RT-PCR, using degenerate primers for cloned GABA transporters, did not result in the amplification of a band from rat choroid plexus RNA. The location of the choroid plexus in the ventricles of the brain, and its role in the secretion of the cerebrospinal fluid, suggest a role for the choroid plexus Na+-GABA transporter in the disposition of GABA in the brain.

Animals↗

Non-contact, two-dimensional measurement of tissue circulation in choroid and optic nerve head using laser speckle phenomenon.

A new apparatus has been developed using the laser speckle phenomenon for non-contact, two-dimensional analysis of tissue circulation in the choroid and optic nerve head (ONH). The fundus was illuminated by a diode laser spot and its image speckle was detected by an image sensor. The difference between the average of the speckle intensity (Imean) and the speckle intensity for successive scannings was calculated, and the ratio of Imean to this difference was defined as normalized blur (NB), which is a quantitative index of blood velocity. The results were displayed on color graphic monitors showing the two-dimensional variation of the NB level in the measurement field. In the rabbit, this apparatus was used to study the relationship between the results of NB measurement and the choroidal blood flow determined by the microsphere technique, the relationship between NB obtained from the ONH tissue free of visible surface vessels and the ocular perfusion pressure (OPP) after a lethal injection of pentobarital, and the effect of intraocular pressure (IOP) on the NB in the choroid or in the ONH. A stepwise reduction in the OPP was introduced by elevating the IOP manometrically. The relative decrease in the average NB over the field measured, NBav, in the choroid with the reduction in OPP showed a significant correlation with the relative change in the blood flow rate determined using the microsphere technique (r = 0.60, P < 0.001). NBav in the ONH had a good correlation with the OPP after a lethal injection of pentobarbital (r = 0.98, P < 0.001). NBav in the choroid decreased with reduction in the OPP. Although NBav in the ONH was little affected by OPP change when OPP was above 40 mmHg, at OPP levels below 40 mmHg, NBav in the ONH decreased along with a reduction in the OPP. These results suggest that by using the present apparatus, the blood velocity in the choroid or ONH under various conditions can be studied non-invasively in the living eye.

Animals↗

Surgical excision versus laser photocoagulation for subfoveal choroidal neovascular membrane with age-related macular degeneration: comparison of visual outcomes.

PURPOSE: This study was designed to compare visual acuity after laser photocoagulation with visual acuity after surgical excision of the subfoveal choroidal neovascular membrane in patients with age-related macular degeneration (AMD). METHODS: We studied 54 patients (56 eyes) who underwent laser photocoagulation and 52 patients (52 eyes) who underwent surgical excision for new subfoveal choroidal neovascular membrane occurring with AMD. We compared mean log of minimal angle of resolution (MAR) visual acuity, and the percentages of eyes showing visual improvement and a visual acuity of 0.1 or better, between the two treatment groups at 12 months after treatment. The groups were also compared according to choroidal neovascular membrane size, ie, 1 disc diameter (DD) or smaller vs larger than 1 DD. RESULTS: Mean corrected visual acuity (P <.01), percentage of eyes with improved vision (P <.01), and percentage with a visual acuity of at least 0.1 (P <.01) were higher in surgically treated eyes. The differences in mean log MAR visual acuity and the percentages were significant only for choroidal neovascular membrane of one DD or less in size. CONCLUSIONS: Postoperative eyes, especially those with choroidal neovascular membranes 1 DD or less in size, had better visual outcomes. Patients who meet our eligibility criteria, especially with small choroidal neovascular membranes 1 DD or less in size, should undergo surgical excision.

Aged↗

Expression of transforming growth factor-beta receptors in normal rat retina and experimental choroidal neovascularization.

PURPOSE: Transforming growth factor-beta (TGF-beta) plays an important role in the development of choroidal neovascularization. TGF-beta transduces signals through the mediation of type I and type II receptors. We investigated the expression of TGF-beta receptors in a normal rat retina and a model of experimentally induced choroidal neovascularization. METHODS: Choroidal neovascularization was induced by laser photocoagulation in rat eyes. The expression of TGF-beta receptors was determined using immunohistochemical and in situ hybridization methods. RESULTS: In normal adult rat retinas, immunoreactivity and mRNA expression of TGF-beta receptor type I (TbetaRI) and TGF-beta receptor type II (TbetaRII) were found in the ganglion cells. During the process of neovascularization, immunoreactivity and mRNA expression of TbetaRI and TbetaRII were widely distributed in laser lesions soon after photocoagulation; thereafter, these receptors were specifically detected in the endothelial cells of choroidal neovascularization. CONCLUSIONS: The expression of TGF-beta receptors in normal rat retinas suggests that TGF-beta plays an important role in the homeostasis of normal retina. The upregulation of TGF-beta receptors in choroidal neovascularization strongly suggests that TGF-beta is most likely transduced through specific receptors and plays an important role in the development of choroidal neovascularization.

Animals↗

Choroiditis in systemic lupus erythematosus: systemic steroid therapy and focal laser treatment.

PURPOSE: To report a rare case of choroiditis in association with systemic lupus erythematosus (SLE). CASE: A 49-year-old woman with a 17-year history of SLE experienced acute vision impairment of her left eye during the remission stage of systemic SLE. Fundus examination revealed a gray-white subretinal exudate with serous retinal detachment. Angiographic examination disclosed choroidal inflammation at the macula and a breakdown of the blood retinal barrier. Retinal burns were applied to the subretinal exudate with an argon laser as in the treatment of central serous retinopathy. Afterward, her visual acuity showed prompt recovery due to the regression of the serous retinal detachment. However, the choroidal inflammation remained until the systemic condition was controlled with steroid therapy. RESULTS: Laser treatment of a subretinal exudate was helpful for the resolution of serous detachment and the prompt improvement of visual acuity, whereas systemic steroid therapy was effective for choroidal inflammation. CONCLUSIONS: Systemic steroid therapy is thought to be effective for SLE choroiditis; however, this therapy is also known to cause serous retinal detachment. Thus, in SLE choroiditis, laser photocoagulation at a leakage point, in addition to systemic steroid therapy, may be helpful for the prompt restoration of vision in patients with serous retinal detachment.

Blood-Retinal Barrier↗

The second-trimester fetus with isolated choroid plexus cysts: a meta-analysis of risk of trisomies 18 and 21.

OBJECTIVE: To assess the risk of trisomy 18 and trisomy 21 associated with isolated choroid plexus cysts diagnosed by ultrasound in the second trimester. METHODS OF STUDY SELECTION: We reviewed the unabridged PREMEDLINE and MEDLINE databases for articles written in the English language regarding second-trimester fetal isolated choroid plexus cysts and trisomies 18 and 21, published in the period 1987-1997. Selection criteria included only second-trimester, prospective studies in which the rate of fetal isolated choroid plexus cysts could be calculated, the number of fetuses with trisomy 18 and 21 was reported clearly, and pregnant women of all ages were included, rather than only those at high risk for aneuploidy due to advanced maternal age. TABULATION AND RESULTS: Thirteen prospective studies, comprising 246,545 second-trimester scans, were selected. Among 1346 fetuses with isolated choroid plexus cysts, seven had trisomy 18, and five had trisomy 21. For each study, a 2 x 2 table was constructed and the likelihood ratio of a positive test was computed. The likelihood ratios for trisomies 18 and 21 were found to be homogeneous (P = .08 for trisomy 18, and P = .16 for trisomy 21). The summary likelihood ratio and 95% confidence interval (CI) for each chromosomal abnormality were calculated using the Mantel-Haenszel fixed effects model of meta-analysis. The summary likelihood ratio for trisomy 18 was 13.8 (CI 7.72, 25.14, P < .001) and for trisomy 21 was 1.87 (CI 0.78, 4.46, P = .16). CONCLUSION: The likelihood of trisomy 18 was 13.8 times greater than the a priori risk in fetuses with isolated choroid plexus cysts diagnosed in the second trimester. However, the likelihood of trisomy 21 was not significantly greater than the a priori risk with isolated choroid plexus cysts. The data supported offering pregnant women karyotyping to rule out trisomy 18 when maternal age at delivery is 36 years or older, or when the risk for trisomy 18 detected by serum multiple-marker screen is more than one in 3000.

Adult↗

Distal anterior choroidal artery aneurysm associated with an arteriovenous malformation. Intraoperative localization and treatment.

BACKGROUND: Distal anterior choroidal artery aneurysms are rare. The outcome of patients with distal anterior choroidal artery aneurysms has been poor, and the treatment of such aneurysms is surgically challenging. CASE DESCRIPTION: The authors describe the case of an 8-year-old girl with a ruptured distal anterior choroidal artery aneurysm associated with an arteriovenous malformation (AVM). The patient experienced sudden onset of headache and vomiting. Computed tomography revealed an intraventricular haemorrhage, and cerebral angiography demonstrated an aneurysm arising from the distal portion of the right anterior choroidal artery. The patient also had an AVM in the ipsilateral temporal lobe fed by the branches of the middle cerebral artery. A right frontotemporal craniotomy was performed with the aid of intraoperative angiography to eliminate both the AVM and the aneurysm. Intraoperative angiography was helpful in confirming the complete removal of the AVM and in accurate localization of the small and deeply placed distal anterior choroidal artery aneurysm. Both the AVM and the aneurysm were successfully treated and the patient was discharged without any neurological deficits. CONCLUSION: This case is the youngest reported patient with a distal anterior choroidal artery aneurysm. This report is also the first to describe an association of such an aneurysm with an AVM. The etiology of the aneurysm formation in this case and surgical strategy for deeply placed vascular lesions are discussed.

Aneurysm, Ruptured↗

Incremental cost effectiveness of laser photocoagulation for subfoveal choroidal neovascularization.

OBJECTIVE: To perform a patient preference-based, incremental cost-effectiveness analysis for laser treatment of subfoveal choroidal neovascularization. DESIGN: Computer-based econometric modeling. METHODS: The cost effectiveness of laser photocoagulation therapy was compared with the natural course of subfoveal choroidal neovascularization. The model applied long-term visual data from previous clinical trials, utility analysis (which reflects patient perceptions of quality of life associated with a health state), decision analysis with Markov modeling, and the economic principles of present value analysis with discounting to account for the time value of money. DATABASE: Data from patients eligible for treatment of subfoveal choroidal neovascularization obtained by researchers in the Macular Photocoagulation Study were used for the analysis. INTERVENTION: Modeled laser therapy for subfoveal choroidal neovasacularization in patients with age-related macular degeneration. MAIN OUTCOME MEASURE: Cost per quality-adjusted life-year ($/QALY gained) associated with laser therapy. RESULTS: Laser photocoagulation therapy for subfoveal choroidal neovascularization, as compared with no treatment, resulted in a mean gain of 0.257 QALYs per treated patient. Using a yearly discount rate of 3% to account for the time value of money and inflation, the resultant $/QALY gained was $5629. Sensitivity analysis used in the cost-effectiveness analysis resulted in a $/QALY gained of $4974 with no gained discount rate and $11,633 with a yearly discount rate of 10%. CONCLUSIONS: The incremental expense of laser therapy for the treatment of subfoveal choroidal neovascularization appears to be highly cost effective. The result, which takes into account patient preference-based utility data, compares quite favorably with other interventional therapies across different medical specialties.

Aged↗

Clinicopathologic features of surgically excised choroidal neovascular membranes.

PURPOSE: The purpose of this study is a descriptive correlation of the clinical, fluorescein angiographic, and pathologic features in a large series of patients who underwent surgical removal of choroidal neovascular membranes. METHODS: The patients' clinical data were recorded for each surgically removed choroidal neovascular membrane received in the authors' laboratory. Fluorescein angiographic characteristics of the membranes, including well-demarcated versus poorly demarcated preoperative appearance, postoperative choroidal atrophy, and membrane recurrence, were recorded whenever possible. The pathologic features of the membranes, including cellular and extracellular constituents, were determined on light and electron microscopic examination. RESULTS: A total of 123 membranes were studied. Underlying diseases in decreasing order of frequency were age-related macular degeneration, ocular histoplasmosis syndrome, myopia, idiopathic and pattern dystrophy. The cellular and extracellular constituents of the membranes were similar, regardless of underlying disease, with the exception of basal laminar deposit, seen almost exclusively in age-related macular degeneration. Well-demarcated membrane components were localized with a central subretinal pigment epithelium fibrovascular core. Poorly demarcated membranes were represented by a subneurosensory retinal (breakthrough) component, although most of these membranes had associated retinal pigment epithelium. Fragments of Bruch's membrane were common in specimens from patients with postoperative choroidal atrophy, and there was generally a lack of vascular channels in membranes that led to recurrence. CONCLUSIONS: This study suggests that choroidal neovascular membranes represent a stereotypic, nonspecific response, regardless of underlying disease. Most membranes are subretinal pigment epithelium, and what is recognized angiographically as a subneurosensory retinal component contains associated retinal pigment epithelium in most instances. Fragments of Bruch's membrane in the specimen correlate with postoperative choroidal atrophy. Lack of vascular channels in the surgical specimen may correlate with a risk for postoperative membrane recurrence.

Adult↗

Breast carcinoma metastatic to the choroid. Analysis of 67 patients.

Two hundred fifty patients with breast carcinoma had ocular examinations between 1973 and 1980. One hundred fifty-two patients were referred because of ocular symptoms or signs, and 98 were asymptomatic. Of the symptomatic patients, 58 had choroidal metastases; nine of the asymptomatic patients with stage IV metastatic breast cancer had choroidal involvement (9.2%). For the 67 patients with metastases, the median age at ocular diagnosis was 51 years. The median interval from primary to choroidal metastases was three years. Survival after ocular diagnosis ranged from one week to four years, with a median of nine months. Among the 67 patients, choroidal tumor deposits occurred bilaterally in 27 patients (40.3%), in 18 right eyes (26.9%), and in 22 left eyes (32.8%). Irradiation led to stabilization or improvement in visual acuity in virtually all cases. Patients in whom acuity was not threatened were observed on medical therapy. Four of these patients eventually required irradiation for increasing disease. Choroidal metastases tended to follow pulmonary dissemination, and to occur with or before central nervous system disease. Choroidal metastases are a common, treatable event in breast carcinoma and may represent the smallest detectable clinical lesion.

Adult↗

Chronic and recurrent choroidal detachment after glaucoma filtering surgery.

Chronic and recurrent choroidal (ciliochoroidal) detachments developed following glaucoma filtration surgery in 14 eyes of 13 patients during a 9-year period. Three specific subgroups were identified: recurrent, inflammatory, and chronic (present for more than 6 months). The factors that may be related to the development of chronic and recurrent choroidal detachments included patient age (mean, 68.8 years), systemic hypertension or atherosclerotic heart disease, hyperopia, aqueous suppressant therapy, ocular inflammation, and full-thickness filtration surgery. A total of 46 choroidal detachments in 14 eyes were recorded and required drainage of suprachoroidal fluid on 34 occasions. All eyes developed visually significant cataracts, and complete resolution of the recurrent or chronic choroidal detachment occurred following cataract extraction in six eyes. Treatment of chronic and recurrent choroidal detachments should include intense therapy of ocular inflammation, discontinuation of medications that can incite ocular inflammation, discontinuation of topical and systemic aqueous suppressant therapy, and when a visually significant cataract is present, cataract extraction combined with a choroidal tap should be performed.

Acetazolamide↗

Melanotic schwannoma of the choroid. Immunohistochemistry and electron microscopic observations.

PURPOSE: The purpose of this article is to describe what is probably the first reported case of a melanotic schwannoma of the choroid and to discuss the clinical and histopathologic features that serve to differentiate this rare intraocular tumor from a malignant melanoma of the choroid. PATIENT AND METHODS: A 21-year-old woman underwent enucleation of the right eye for a slowly enlarging pigmented choroidal mass that was associated with ipsilateral blindness. The tumor was studied by light microscopy, immunohistochemistry, and electron microscopy. FINDINGS: The tumor was composed of fascicles and whorls of pigmented and nonpigmented plump spindle cells that had light microscopic features of a schwannoma. The tumor cells showed immunoreactivity to S-100 protein and HMB-45. Electron microscopy showed cytoplasmic processes surrounded by a continuous basement membrane and abundant extracellular collagen. The pigmented spindle-shaped cells contained melanosomes in different stages of melanogenesis. The findings were compatible with a melanotic schwannoma. CONCLUSION: Melanotic schwannoma has been reported in soft tissues, peripheral nerves, and in the orbit. To the authors' knowledge, this is the first report of a melanotic schwannoma of the choroid. This extremely rare pigmented choroidal tumor may be very difficult to differentiate clinically from choroidal melanoma.

Adult↗

Subfoveal neovascular membrane removal in patients with traumatic choroidal rupture.

PURPOSE: To describe the clinical outcomes of patients undergoing pars plana vitrectomy to remove subretinal neovascular membranes caused by traumatic choroidal ruptures. METHODS: Three patients with traumatic choroidal rupture in whom subfoveal choroidal neovascularization developed underwent pars plana vitrectomy with surgical excision of the neovascular membrane. Surgical specimens were examined histopathologically in two patients. RESULTS: The choroidal neovascularization was removed completely in each patient. Visual results were excellent with visual acuities improving to 20/30 or better in each patient. Recurrence of choroidal neovascularization has not been observed. Fibrovascular membranes with reactive retinal pigment epithelium were observed in two specimens examined histopathologically. CONCLUSION: Surgical removal of subretinal neovascular membranes emanating from traumatic choroidal ruptures produced an excellent visual outcome in three patients studied. The neovascular membranes, which were removed with minor disturbance to the underlying pigment epithelium, have similar characteristics to those obtained from patients with ocular histoplasmosis syndrome.

Adult↗

Idiopathic polypoidal choroidal vasculopathy of the macula.

OBJECTIVE: The authors evaluated the clinical, fluorescein, and indocyanine green (ICG) angiographic characteristics of the macular variant of idiopathic polypoidal choroidal vasculopathy (IPCV). DESIGN: Observational case series. PARTICIPANTS: The records, photographs, and fluorescein and ICG angiograms of eight eyes of seven patients with IPCV lesions confined to the macula were reviewed. MAIN OUTCOME MEASURES: The visual acuity, fundus examination, fluorescein and ICG angiographic characteristics, and clinical course were compared. RESULTS: All patients demonstrated polypoidal lesions arising from macular choroidal vessels on ICG angiography. One patient had bilateral lesions. These lesions appeared hyperfluorescent in the early phases of both fluorescein and ICG angiography. Late-phase leakage was seen in cases associated with subretinal fluid or exudate. None of these patients demonstrated polypoidal lesions arising from the peripapillary choroidal circulation or peripapillary choroidal neovascularization. Three eyes with polypoidal lesions that were associated with subretinal fluid and exudates were treated with photocoagulation. Five eyes were not treated. Final visual acuity ranged from 20/20 to hand motions. Severe visual loss was associated with vitreous and subretinal hemorrhage, but this resolved without permanent severe visual loss in several cases. CONCLUSIONS: In the macular variant of IPCV, ICG and fluorescein angiography demonstrate characteristic macular polypoidal lesions without evidence of peripapillary lesions. The vascular origin of these polypoidal lesions appears to be the macular choroidal circulation. This is distinguished from classic IPCV, in which lesions appear to arise from the peripapillary choroidal circulation. Visual prognosis appears to be good, with most patients retaining visual acuity of 20/80 or better. If subretinal fluid or exudates reduce visual acuity, photocoagulation should be considered.

Aged↗

Circumscribed choroidal hemangioma: characteristic features with indocyanine green videoangiography.

OBJECTIVE: To determine the characteristic features of indocyanine green videoangiography (ICG-V) of circumscribed choroidal hemangioma. DESIGN: Prospective, observational case series. PARTICIPANTS: Twenty-five eyes of 25 consecutive patients with circumscribed choroidal hemangioma. INTERVENTION: Indocyanine green videoangiography and intravenous fluorescein angiography (IVFA) were prospectively performed and reviewed. The specific features on ICG-V were compared with features of IVFA. MAIN OUTCOME MEASURES: The behavior of circumscribed choroidal hemangioma cases was observed with ICG-V and IVFA. RESULTS: On ICG-V, earliest hyperfluorescence of circumscribed choroidal hemangioma was achieved at a mean of 27.6 seconds (range, 13-62 seconds), whereas maximum hyperfluorescence occurred at 222 seconds (range, 33-707 seconds). In the late frames, all eyes demonstrated a relative decrease in fluorescence, including 18 eyes (72%) that demonstrated "washout" of the dye. Other findings on ICG-V included intrinsic vessels in 19 eyes (76%), a late hyperfluorescent rim in 19 eyes (76%), and late frame hot spots in 14 eyes (56%). On IVFA, the earliest hyperfluorescence was achieved at a mean of 24 seconds (range, 10-66 seconds), whereas maximum hyperfluorescence occurred at a mean of 76.3 seconds (range, 21-720 seconds). Increasing hyperfluorescence in the late frames was found in all cases. Other findings included intrinsic vessels in 12 eyes (48%) and hot spots in the late frames in 9 eyes (36%). CONCLUSIONS: Circumscribed choroidal hemangioma have specific characteristics on ICG-V that are not visualized with IVFA. We believe that ICG-V may become an important noninvasive tool for the diagnosis of choroidal hemangioma.

Choroid Neoplasms↗

Claudin-1, claudin-2 and claudin-11 are present in tight junctions of choroid plexus epithelium of the mouse.

The choroid plexus epithelium forms the blood-cerebrospinal fluid (CSF) barrier and is responsible for the secretion of the CSF from the blood. The morphological correlate of the blood-CSF barrier are the tight junctions of choroid plexus epithelium. By freeze-fracture electron microscopy it has been demonstrated that choroid plexus epithelial tight junctions form parallel strands resembling those of Sertoli cells building the blood-testis barrier and those of the myelin sheaths of oligodendrocytes. As the oligodendrocyte specific protein/claudin-11 has been shown to be the central mediator of parallel-array tight junctions in Sertoli cells and myelin sheaths in mice, we asked whether claudin-11 is present in the tight junctions of choroid plexus epithelial cells of the mouse. Here, we present the first direct evidence that claudin-11 besides claudin-1 and -2, occludin and the zonula occludens protein ZO-1 is present in choroid plexus epithelial tight junctions. During inflammation in the central nervous system such as experimental autoimmune encephalomyelitis, the molecular composition of choroid plexus epithelial tight junctions does not change considerably. Their unique molecular composition, with claudin-11 accompanied by claudin-1 and claudin-2 points to a unique regulatory mechanism of the blood-CSF-barrier function.

Animals↗

[Choroid metastases revealing pulmonary adenocarcioma resolved with chemotherapy].

Lung cancer is the leading cause of choroidal metastasis in men, but choroidal metastasis is rarely inaugural. With the advent of new generations of chemotherapy molecules non-small-cell lung cancer (NSCLC) has become more chemosensitive. Choroidal metastasis may respond to chemotherapy. We report a case of a 52-year-old men who developed choroidal metastasis revealing pulmonary adenocarcinoma confirmed by the bronchial biopsy. Systemic chemotherapy using gemcitabine-cisplatin led to total involution of the choroidal metastasis with improvement of the visual acuity in one eye and stabilization in the other. Systematic search for lung cancer is required in patients presenting choroidal metastasis. If compatible with the patient's general status, histologically-adapted chemotherapy must be instituted. This approach can avoid the use of radiotherapy and therefore deterioration of visual acuity after radiation.

Adenocarcinoma↗

Characterization of the amino acid transport of new immortalized choroid plexus epithelial cell lines: a novel in vitro system for investigating transport functions at the blood-cerebrospinal fluid barrier.

PURPOSE: To establish and characterize a choroid plexus epithelial cell line (TR-CSFB) from a new type of transgenic rat harboring the temperature-sensitive simian virus 40 (ts SV 40) large T-antigen gene (Tg rat). METHODS: Choroid plexus epithelial cells were isolated from the Tg rat and cultured on a collagen-coated dish at 37 degrees C during the first period of 3 days. Cells were subsequently cultured at 33 degrees C to activate large T-antigen. At the third passage, cells were cloned by colony formation and isolated from other cells using a penicillin cup. RESULTS: Five immortalized cell lines of choroid plexus epithelial cells (TR-CSFB 1 approximately 5) were obtained from two Tg rats. These cell lines had a polygonal cell morphology, expressed the typical choroid plexus epithelial cell marker, transthyretin, and possessed Na+, K+-ATPase on their apical side. TR-CSFBs cells expressed a large T-antigen and grew well at 33 degrees C with a doubling-time of 35 approximately 40 hr. [3H]-L-Proline uptake by TR-CSFB cells took place in an Na+-dependent, ouabain-sensitive, energy-dependent, and concentration-dependent manner. It was also inhibited by alpha-methylaminoisobutylic acid, suggesting that system A for amino acids operates in TR-CSFB cells. When [3H]-L-proline uptake was measured using the Transwell device, the L-proline uptake rate following application to the apical side was five-fold greater than that following application to the basal side. In addition, both Na+-dependent and Na+-independent L-glutamic acid (L-Glu) uptake processes were present in TR-CSFB cells. CONCLUSIONS: Immortalized choroid plexus epithelial cell lines were successfully established from Tg rats and have the properties of choroid plexus epithelial cells, and amino acid transport activity was observed in vivo.

Amino Acids↗