Adenoma of the nonpigmented ciliary epithelium

PURPOSE: To report the clinicopathologic features of an adenoma of the nonpigmented ciliary epithelium. DESIGN: Single interventional case report. METHODS. A nonpigmented iris and ciliary body tumor was diagnosed in a 66-year-old woman who complained of blurred vision related to a unilateral cataract. A combined cataract surgery and partial lamellar sclerouvectomy was performed. RESULTS: Histopathologic findings disclosed an adenoma of the nonpigmented ciliary epithelium. CONCLUSIONS: Unilateral cataract in an adult patient can be rarely related to a tumor growing from the ciliary epithelium. Adenoma of the non pigmented ciliary epithelium may mimic an amelanotic melanoma. Partial lamellar sclerouvectomy is an effective method to manage this condition and to confirm the diagnosis.     

Characterization of human and rabbit pigmented and nonpigmented ciliary body epithelium

Nonpigmented epithelial (NPE) and pigmented epithelial (PE) cells were carefully dissected from both human and rabbit ciliary processes and have been maintained in vitro and partially characterized by morphology and immunocytochemical techniques using polyclonal and monoclonal antibodies against S-100 proteins, collagen type I and type III. The tissue distribution of these proteins was studied in formalin fixed deparaffinized tissue sections of human and rabbit eyes by immunoperoxidase staining techniques. Both NPE and PE cell lines from human and rabbit showed hexagonal morphology by light microscopy; distinct granules containing pigment could be visualized in the PE cell lines, but not in the NPE cells. Antibodies against S-100 proteins stained NPE layer intensely and PE layer slightly in the human tissue sections. The staining was less intense in rabbit tissues than human tissues. The ciliary body stroma was positive for collagen type III and negative for collagen type I or S-100.     

Primary culture of porcine nonpigmented ciliary epithelium

PURPOSE: Primary culture of nonpigmented ciliary epithelium (NPE) has proved difficult in the past. Here we report development of a method of growing and maintaining primary cultures of NPE from porcine eye. Studies were conducted to confirm that the cultured NPE expressed proteins characteristic of native NPE. METHODS: Intact rings of NPE were isolated from adult pig eyes. A mixture of hyaluronidase and collagenase was used to detach the cells from the basement membrane and vitreous. Dispersed cells were seeded at high density and grown in DMEM with 20% fetal bovine serum under 5% CO2 and 95% air. Protein expression was examined by immunohistochemistry and immunoblot analysis. RESULTS: NPE cells were grown in primary culture and maintained up to 10th passage. Analysis of the ciliary body showed three Na, K-ATPase isoforms (alpha 1, alpha 2, alpha 3) and three nitric oxide synthase isoforms (eNOS, nNOS, iNOS) enriched in the NPE layer but weaker or absent in the PE layer. Each of these proteins as well as the tight junction-specific protein ZO-1 was detected in the cultured NPE. CONCLUSIONS: We developed a simple and reliable way to isolate, culture, and maintain NPE cells from porcine eyes. Success of the method hinged on our ability to isolate pure NPE in large number, detach the cells from the vitreous, and seed the cells at high density. The cultured cells express several proteins that are characteristic of native NPE. NPE cells cultured in this way may prove to be valuable for the study of ciliary body function.     

Adenoma of the nonpigmented epithelium of the ciliary body

A 42-year-old woman developed a ciliary body mass which indented the lens equator and produced a dense focal cataract in the right eye. The clinical diagnosis was malignant melanoma of the ciliary body, and the lesion was removed by a large iridocyclectomy. Histopathologic examination revealed an acquired adenoma of the non-pigmented ciliary epithelium. The clinical and histopathologic features of this rare intraocular tumor are discussed with emphasis upon its differentiation from malignant melanoma.     

Adenoma of the nonpigmented epithelium of the ciliary body.

A 56-year-old man presented with a left ciliary body mass, anterior vitreous hemorrhage and a subluxed, cataractous lens. The clinical course included rapid enlargement of the mass, anterior uveitis, cataract progression and secondary glaucoma. Investigation included fluorescein angiography, ultrasonography and computed tomography. The eye was enucleated because of progressive enlargement with poor vision and uncontrolled secondary glaucoma. Histopathological examination showed an adenoma of the nonpigmented ciliary epithelium with cystic areas of hyaluronidase-sensitive acid mucopolysaccharide. The mass distorted the iris, occluded the angle structures and produced a complete cataract. The basement membrane of the adjacent ciliary processes was extensively thickened. The authors discuss the clinical association with vitreous hemorrhage and the local damage caused by this benign tumour.     

Effect of acetylcholine on membrane potential of cultured human nonpigmented ciliary epithelial cells

Human nonpigmented ciliary epithelial cells (NPE) were grown in tissue culture after transformation with an origin-defective mutant of SV-40 DNA. In these cells membrane potentials (V) were measured using the microelectrode technique. Addition of 10(-4) M acetylcholine led to a bisphasic voltage response. An immediate, transient hyperpolarization was followed by a sustained depolarization below the steady state level. These responses were irreversibly blocked by 10(-5) M atropine. In Ca2+-free media the initial addition of acetylcholine resulted in an unchanged voltage response. A second application of acetylcholine in Ca2+-free solution evoked only an abortive response of V, and further addition had no effect on V. In the presence of Ca2+ channel blockers (10(-5) M verapamil, 1 mM Co2+) the acetylcholine-induced response of the membrane potential was not changed. The initial hyperpolarization induced by acetylcholine was reduced by 33 +/- 3% (n = 6) in the presence of 2 mM Ba2+ and by 79 +/- 6% (n = 6) in the presence of 1 mM quinidine. Moreover, the amplitude of the hyperpolarization was dependent on the extracellular K+ concentration. With increasing extracellular K+ concentration (and decreasing transmembrane K+ gradient) the acetylcholine-induced hyperpolarization was reduced. To further elucidate the role of Ca2+ in the acetylcholine-induced responses, we measured cytoplasmic Ca2+ activity using the fluorescence of intracellularly trapped Fura-2. Cytoplasmic Ca2+ activity increased immediately and transiently upon addition of acetylcholine. We conclude that acetylcholine transiently hyperpolarizes V in cultured human NPE by activation of K+ channels mediated by mobilization of Ca2+ from intracellular stores.     

Membrane voltage recordings in a cell line derived from human ciliary muscle

A smooth muscle cell line (H7CM) was established from the ciliary muscle of a 1-day-old human infant. The cultured cells had a normal female karyotype (46 XX) and could be maintained in cell culture for at least 11 generations. A common feature of confluent cultures was the presence of abundant bundles of 6-7 nm microfilaments associated with dense bodies. Both the ultrastructural appearance and the presence of smooth muscle-specific alpha-isoactin (also present in the human ciliary muscle in situ) support the smooth muscle origin of the H7CM cell line. Continuous membrane voltage (Vm) recordings were obtained in confluent monolayers of H7CM cells using glass microelectrodes. Resting Vm in 105 impalements averaged -66.2 +/- 0.7 mV (mean +/- standard error of the mean). In this system, rapid membrane transients induced by changing of the superfusing test solutions were detectable. Relative K+ conductance was characterized, and the contribution of electrogenic sodium/potassium adenosine triphosphatase to Vm was investigated. Under control conditions, H7CM cells were electrically quiescent. However, action potentials could be induced by application of 10 mM barium. Barium-induced action potentials were not abolished by removal of extracellular Na+ nor were they inhibited by the presence of tetrodotoxin. However, they were blocked by verapamil, fulfilling criteria believed to be typical for smooth muscle cells. Acetylcholine, carbachol, and to a lesser extent pilocarpine induced a reversible Vm depolarization. The effect of acetylcholine was blocked by atropine, implying muscarinic receptor involvement in the Vm response. Collectively, these findings show the potential usefulness of cultured ciliary muscle cells in understanding further the cellular mechanisms underlying drug-induced contraction of the human ciliary muscle.     

Neurotransmitters and neuropeptides stimulate inositol phosphates and intracellular calcium in cultured human nonpigmented ciliary epithelium.

The effects of several neurotransmitters and neuropeptides on the inositol phosphate/diacylglycerol pathway were examined in human nonpigmented ciliary epithelial cells. Maximal stimulation of inositol phosphate formation by vasopressin (approximately 3-fold), carbachol (approximately 2-fold) and histamine (approximately 5-fold) was observed only after cells had been confluent for at least six days. In contrast, a response to bombesin (approximately 3-fold) declined with extended time in confluent culture. Inositol monophosphate, inositol bisphosphate, and inositol trisphosphate all were stimulated by these agonists. Dose-response studies showed a close correlation between the EC50s of the different agonists when elevation of inositol phosphates was compared to stimulation of intracellular Ca2+, with the exception of bombesin. Preliminary pharmacologic characterization of the receptors for vasopressin, carbachol, and bombesin provided rank order of potencies for selective agonists and antagonists. The data suggest that the muscarinic receptor on human NPE cells is the M3 subtype, whereas the vasopressin receptor, as defined by its linkage to the inositol phosphate/diacylglycerol pathway, is the V1 subtype.     

Adenoma arising from nonpigmented ciliary epithelium concomitant with neovascularization of the optic disk and cystoid macular edema

PURPOSE: To report a case of adenoma of the nonpigmented ciliary epithelium concomitant with marked neovascularization of the optic disk and cystoid macular edema (CME). DESIGN: Observational case report. METHODS: A 34-year-old woman presented with a nonpigmented, vascularized tumor behind the iris and neovascularization of the optic disk (NVD). Visual acuity decreased gradually as a result of the development of CME. RESULTS: Iridocyclectomy to excise the tumor was performed 8 months after initial examination. Histopathologic study revealed an adenoma arising from the NPCE. The levels of vascular endothelial growth factor were significantly elevated in both aqueous and vitreous humor obtained at surgery. The NVD and CME regressed after surgery, and the postoperative visual acuity improved to 20/40. CONCLUSIONS: NVD and CME may develop secondary to adenoma of the nonpigmented ciliary epithelium. Increased levels of vascular endothelial growth factor in intraocular fluids may play a role in NVD and CME development.     

Desmosomal-mitochondrial complexes in human nonpigmented ciliary and retinal pigment epithelia

In the normal human nonpigmented ciliary epithelium structural associations between mitochondria and desmosomes are described electron-microscopically: either a single desmosome or a linear array of several desmosomes joined by filamentous bundles is associated with one or two mitochondria (19.6 +/- 5.4%; n = 29). The frequency of occurrence of these complexes was studied in five different regions of the ciliary body; analysis of covariance revealed a significantly increased number of associations in the ciliary processes. Further, the age dependence of their occurrence was examined in 29 different age classes (15 to 86 years); correlation analysis revealed no correlation between age and number of associations. Similar complexes occur, in addition, in the retinal pigment epithelium, but have not been observed in ciliary pigmented, lens, iris and corneal epithelia. Desmosomal-mitochondrial complexes are considered to be a characteristic feature of basic physiological significance of certain epithelia only. The cytochemical demonstration of calcium in the associated mitochondria provides support for the hypothesis that the mitochondria may serve as buffers for intracellular calcium by controlling the local calcium concentration, thus increasing the stability and functional integrity of desmosomal junctions in secretory or actively transporting epithelia with high endogenous calcium levels.     

Adenocarcinoma of the nonpigmented ciliary epithelium: report of two cases with immunohistochemical findings

BACKGROUND: Acquired neoplasms arising from the nonpigmented ciliary epithelium (NPCE) are much less common than uveal melanocytic proliferations. We report two cases of acquired neoplasms arising from the NPCE with immunohistochemical findings. METHODS: Case reports. RESULTS AND CONCLUSIONS: Patient 1 was a 39-year-old man who presented with a pigmented mass behind the iris and secondary exudative retinal detachment. The eye also developed neovascular glaucoma. Patient 2 was a 44-year-old woman with a ciliary body mass but without symptoms. Both of these tumors were classified histologically as low-grade adenocarcinomas of the NPCE from specimens successfully removed by iridocyclectomy. Immunohistochemical findings confirmed the origin of the tumor cells; however, some changes in the immunoreactivity to cytokeratin AE1 and epithelial membrane antigen were found.     

Stimulation of active sodium-potassium transport by hydrogen peroxide in cultured rabbit nonpigmented ciliary epithelium.

PURPOSE: Studies were conducted to examine the effect of hydrogen peroxide on active sodium-potassium transport in a cell line derived from nonpigmented ciliary epithelium of the rabbit eye. METHODS: Studies were carried out using a rabbit nonpigmented ciliary epithelium cell line. 86Rb uptake by intact cells was measured in the presence or absence of ouabain. The ouabain-sensitive potassium (86Rb) uptake rate was used as an index of the rate of active sodium-potassium transport. Cell sodium content was measured by atomic absorption spectrophotometry. Na,K-ATPase activity was determined by measuring ATP hydrolysis in the presence or absence of ouabain, using membrane material isolated by centrifugation of cell homogenates. RESULTS: Ouabain-sensitive potassium (86Rb) uptake rate measured in cells that had been preincubated with 200microM hydrogen peroxide for either 30 min or 60 min was increased to 196% and 181% of the control uptake rate, respectively. Lesser concentrations of hydrogen peroxide caused lesser degrees of stimulation. 200microM hydrogen peroxide caused an increase of cell sodium content. Such a change of cell sodium content is likely to be responsible, at least in part, for the observed stimulation of active sodium-potassium transport. However, the response may also be partly dependent on activation of a protein kinase since the serine/threonine protein kinase inhibitors staurosporine (1microM) and H-89 (20microM) were both found to prevent the stimulatory effect of 200microM hydrogen peroxide on ouabain-sensitive potassium (86Rb) uptake. Interestingly, neither H-89 nor staurosporine prevented the elevation of sodium content in cells that received 200microM hydrogen peroxide. CONCLUSIONS: Taken together, these findings suggest a low concentration of hydrogen peroxide causes increased sodium entry into the cell and also activates a protein kinase-dependent mechanism for sodium pump stimulation. The protein kinase-dependent mechanism does not appear to be triggered by an increased rate of sodium entry since staurosporine did not prevent the stimulation of ouabain-sensitive potassium (86Rb) uptake elicited by an increase in sodium permeability caused by amphotericin B.     

丝裂霉素C对兔眼睫状体无色素上皮细胞的毒性作用

目的 观察兔眼巩膜咬切术中应用０．２ｍｇ／ｍｌ丝裂霉素Ｃ（ＭＭＣ）后,睫状体无色素上皮细胞的病理形态学的改变,探讨ＭＭＣ对睫状体的毒性作用。方法 在兔眼巩膜咬切术中用含０．２ｍｇ／ｍｌ的ＭＭＣ０．１ｍｌ的海绵块,置于Ｔｅｎｏｎ囊和巩膜之间共５分钟,并用２０ｍｌ生理盐水冲洗,术后第７天及２８天,采用光镜观察睫状体,透射电镜观察其无色素上皮细胞。结果 术后第７天睫状体无色素上皮细胞水肿,线粒体丰富、肿