Pattern dystrophy of the retinal pigment epithelium in Crohn's disease. A case report

The authors describe a case of bilateral pattern dystrophy of the retinal pigment epithelium in a man with Crohn's disease. The patient was examined every 6 months over a follow-up of 30 months. The right eye presented a macroreticular dystrophy while in the left eye a butterfly pattern dystrophy was diagnosed. During the follow-up period the retinal lesion changed; in the right eye the lesion increased in size, while in the left eye the morphology of the lesion passed from the butterfly to Sj?gren's type. This report adds a new ocular manifestation of Crohn's disease, emphasizing the importance of the ophthalmological follow-up in the recognition of posterior segment complications associated with this inflammatory bowel disease.     

A case of acute diffuse atrophy of retinal pigment epithelium

PURPOSE: To report a case of acute bilateral visual disturbance where the ocular fundus changed like retinitis pigmentosa in a short time. PATIENT: 26-year-old man. FINDINGS: In initial examination, the patient's visual acuity was 0.01 OD and 0.02 OS with myopic correction, but his fundus did not look abnormal. Fluorescein angiogram showed marked background hyperfluorescence and dye leaking to the vitreous. After 2-3 weeks, the fundus appearance changed like retinitis pigmentosa. Best corrected visual acuity became 1.0 OD and 0.9 OS after steroid pulse therapy. We were unable to find the cause of this disease in spite of blood tests and other examinations. CONCLUSION: This case with acute diffuse atrophy of retinal pigment epithelium and damage of the function of blood-retinal barrier was considered remarkably rare.     

Adenocarcinoma of retinal pigment epithelium.

This report describes a 41-year-old man with an intraocular tumour misinterpreted clinically as choroidal melanoma. The fluorescein angiographic features were not fully characteristic of uveal malignancy, and indeed histopathology revealed the diagnosis of adenocarcinoma of the retinal pigment epithelium. It is suggested that, in cases with the fundus and angiographic findings described here, the rare possibility of adenocarcinoma of retinal pigment epithelium should be kept in mind. Of particular interest were the changing pathological findings in the various parts of the tumour, which paralleled the fluorescein angiographic pattern.     

Mannose-sensitive HRP endocytosis by the retinal pigment epithelium.

Mannose-sensitive endocytosis by rat retinal pigment epithelium (RPE) explants was characterized using the mannose-rich glycoprotein horseradish peroxidase (HRP). The number of HRP-containing endosomes in the RPE was morphologically quantitated by light microscopy while the amount of HRP ingested was biochemically quantitated by enzyme assay. HRP internalized via a mannose-sensitive receptor was differentiated from fluid-phase uptake in competitive inhibition studies using D-mannose. Morphological results showed that most HRP-containing endosomes formed within the first 15 min of incubation and showed little increase in number during 4 hr of continued incubation with HRP. In contrast, the biochemical assay showed a steady increase in the amount of HRP in RPE endosomes measured over time. The addition of 10 mM D-mannose to the incubation medium was associated with a significant decrease in both the number of HRP-containing endosomes and the amount of HRP ingested by RPE explants. Values indicate that half of the total uptake of HRP is mediated by a mannose-sensitive receptor while the balance is ingested via non-specific fluid-phase endocytosis.     

Tears of detached retinal pigment epithelium.

Ripping of detached pigment epithelium appears to be a common sight-threatening complication of pigment epithelial detachments and occurs at the junction of the detachment and flat pigment epithelium. The characteristics of the detachment prior to the rip suggest that the tear occurs in pigment epithelium which is detached without its basement membrane. The tear is followed by retraction of the pigment epithelium, revealing bare Bruch's membrane. The defect may remain apparently unaltered, or may be recovered by normal looking pigment epithelium, but most commonly is replaced by a fibrous plaque. Most patients had a profound reduction in visual acuity.     

''Blow-outs'' in the retinal pigment epithelium.

A hole was detected in the epithelium of a retinal pigment epithelium (RPE) detachment in two patients. Leakage through the hole led to an elevation of the overlying neurosensory retina in each case. The resulting vision was 20/70 in one eye and 20/30 in the other. The defects in the RPE occurred in a setting different from that usually seen with tears in the pigment epithelium and had a different clinical appearance.     

Zinc uptake by primate retinal pigment epithelium and choroid.

We studied zinc uptake by nonhuman primate retinal pigment epithelium (RPE) and choroid, using 65Zn as a probe. With intravenously administered 65ZnCl2, virtually all detectable tracer was lost from the plasma after 20 hours but the pigment epithelium-choroid showed prominent uptake and retention. Plasma concentrations of oral 65ZnO remained high 20 hours after feeding. Uptake and retention of orally administered 65Zn as 65ZnO from the bloodstream by the RPE/choroid was avid in both young and old animals. Excretion in urine and feces was minimal. All pigmented ocular tissues took up and retained 65Zn. A survey of total zinc content of human and nonhuman primate ocular tissues showed that the pigmented tissues had consistently higher concentrations of zinc. Our results demonstrate for the first time direct uptake and retention of zinc from the blood by primate RPE and other ocular tissues.     

Photosensitization of retinal pigment epithelium by protoporphyrin IX

Background: Clinical evidence of injury to the retinal pigment epithelium is an important feature of age-related macular degeneration, but the mechanism of this injury is unknown. Blue-light-dependent activation of the blood-borne photosensitizer protoporphyrin IX is known to produce free radicals which may damage cells and tissues. This study was undertaken to determine the effect of blue light and protoporphyrin IX on retinal pigment epithelial cells in vitro. • Methods: Third-passage porcine retinal pigment epithelial cells were plated in six-well culture plates at 100 000 cells/well and grown to confluence. Retinal pigment epithelial cells were then incubated in culture media with and without 35 μg/dl protoporphyrin IX and exposed to low intensity (118 μW/cm²) blue, blue-free, or full-spectrum white light in an irradiating incubator for 16 h on/8 h off cycles for 7 days. Some of the wells were shielded from light (dark controls). Retinal pigment epithelial cells were examined by light microscopy and were trypsinized and counted after 7 days. • Results: White light with and without protoporphyrin IX and protoporphyrin IX in dark conditions did not decrease the retinal pigment epithelial cell count significantly. Blue light alone and blue light with protoporphyrin IX decreased the cell count by 22 ± 4% and 35 ± 3% compared to the controls, respectively. • Conclusion: Blue wavelength light without exogenous protoporphyrin IX has a cytotoxic effect on confluent cultures of retinal pigment epithelium, suggesting that endogenous photosensitizers may be present in retinal pigment epithelial cells. Protoporphyrin IX has an additive cytotoxic effect in the presence of blue light, suggesting that this photosensitizer is capable of mediating blue-light-induced retinal pigment epithelial damage. Since protoporphyrin IX is present in blood and tissue fluids, and the retina is chronically exposed to light, protoporphyrin IX-mediated free radical formation may occur in vivo and may play a role in retinal pigment epithelial changes that occur early in the pathogenesis of age-related macular degeneration. Received: 12 February 1997 Revised version received: 26 May 1997 Accepted: 31 May 1997     

酒精中毒致视网膜色素上皮损伤观察

目的 观察急慢笥酒精中毒后视网膜色素上皮损伤情况。方法 对９例（１８眼）急慢性酒精中毒患者进行了眼底荧光血管造影（ＦＦＡ）及视觉电生理（ＥＲＧ,ＶＥＰ）检查。结果 ２例（４眼）急性酒精中毒者经药物治疗后视力完全恢复,１例（２眼０ＦＦＡ见双眼底视网膜色素上皮弥漫性损伤。慢性酒精中毒６例１２眼经药物后ＦＦＡ为双眼底视风纱上皮炎改变,ＥＲＧ,ＶＥＰ无好转。结论 急性酒精中毒引起的眼部改变大多时恢复,慢性     

Bilateral tears of the retinal pigment epithelium.

This paper describes bilateral tears of the retinal pigment epithelium (RPE) which followed photocoagulation treatment of retinal pigment epithelial detachment (PED) in the right eye and which occurred spontaneously in the left eye. A 66-year-old Japanese male presented with PED approximately 4 X 6 disc diameters in size in his right eye, and one disc diameter in the left eye, both in the macular regions. The right PED was treated by placing a row of argon laser photocoagulation along the margin of the PED, with avoidance of the papillomacular bundle. Five days after treatment the PED enlarged peripherally beyond the coagulated site. Nineteen days later an RPE tear developed at the temporal edge of the detachment in the right eye. The remaining detached RPE retracted centrally, forming curled folds. About 40 days after the initial examination the patient complained of sudden reduction of vision in his left eye. At this time an enlargement of the PED was found in his left eye. One week after this examination a small RPE tear was found in the nasal border of the PED in the left eye. The tear in the left eye gradually developed centrally to the fovea.     

Idiopathic multiple retinal pigment epithelial detachments – A case report

Retinal pigment epithelial detachment, often asymptomatic is a common retinal finding. Multiple serous retinal pigment epithelial detachment especially in a female is very uncommon. We describe a case of multiple retinal pigment epithelial detachments throughout the fundus in a 51-year old female otherwise asymptomatic. Indocyanine green angiography and fundus auto fluorescence showed abnormalities with a normal systemic work-up. This is the first report of an asymptomatic patient correlating angiogram with auto fluorescence in multiple serous retinal pigment epithelial detachments.     

In vitro stimulation of retinal pigment epithelium proliferation by taurine.

Taurine is an amino acid that is essential for retinal integrity and function. Although it has been suggested that the ratio of melatonin to taurine in the interphotoreceptor matrix may regulate the phagocytosis of outer segments by retinal pigment epithelial (RPE) cells, the effect of taurine on the RPE has not been studied. Using cultured RPE cells, we found that in vitro taurine specifically stimulated proliferation of human and rabbit RPE, but had only minimal effect on cultured scleral fibroblasts. The RPE proliferation was due to more cells entering into S-phase and thus an increase in DNA synthesis, was not dependent upon cell density, and was most pronounced in the presence of a low concentration of fetal bovine serum.     

维拉帕米体外诱导人视网膜色素上皮细胞的凋亡

目的:探讨维拉帕米诱导体外培养的人视网膜色素上皮细胞凋亡的有效作用浓度和时间。方法:采用HE染色﹑AO荧光染色和透射电镜以及流式细胞仪检测80和160mg/L维拉帕米作用12￣72h致凋亡作用。结果:80和160mg/L维拉帕米均可诱导体外培养的人视网膜色素上皮细胞凋亡。经统计学分析其差异具有显著性,且具有明显的时间—剂量关系,160mg/L维拉帕米作用72h时,凋亡率最高达49.3%。结论:维拉帕米能诱导体外培养的人RPE细胞凋亡。     

Preserved para-arteriolar retinal pigment epithelium retinitis pigmentosa.

In two patients, we studied retinitis pigmentosa with preservation of the retinal pigment epithelium adjacent to and under the retinal arterioles (despite panretinal degeneration). Both patients with preserved para-arteriolar retinal pigment epithelium also exhibited a peculiarly strong hyperopia. In addition to previously reported features, these patients also had sheathing of the major vascular arcades, which suggested a vascular involvement in this uncommon form of retinitis pigmentosa.     

Cl- transport in frog retinal pigment epithelium.

Cl- transport across the retinal membrane of the frog retinal pigment epithelium was studied by means of double-barrelled Cl- selective microelectrodes. Three types of experiments were performed. In the first group of experiments, the ionic dependence of Cl- influx across the retinal membrane was studied. The intracellular Cl- activity was first decreased by perfusing the retinal side of the epithelium with low Cl- solutions (3.6 mM Cl-); then the perfusate was changed to high Cl- solutions (90.1 mM), and the resulting Cl- influx was studied. In these experiments, the combined presence of extracellular Na+ and K+ was a necessary condition for Cl- influx across the retinal membrane. This supports the hypothesis of Na+,K+,Cl- co-transport across this membrane. In a second group of experiments, the effect of furosemide was studied. Furosemide (100 microM) inhibited Cl- influx when the retinal extracellular Cl- concentration was increased from 3.6 to 90.1 mM. When administered to cells in steady state, furosemide in concentrations between 5 and 1000 microM decreased the intracellular Cl- activity. Michaelis-Menten analysis yielded a Ki for furosemide of 7 +/- 2 microM. The effect of furosemide on the intracellular Cl- activity required the combined presence of extracellular Na+ and K+. When the retinal extracellular K+ concentration was increased to between 0 and 10 mM, the furosemide-sensitive Cl- influx across the retinal membrane increased. Michaelis-Menten analysis yielded a half maximal stimulation at an extracellular K+ concentration of 0.5 mM. Stimulation of the epithelium with 1 mM cAMP and 0.5 mM IBMX reduced the effect of furosemide on the intracellular Cl- activity by 26%. In a third group of experiments, the effect of transepithelial currents on the intracellular Cl- activity was investigated. Currents that depolarized the choroidal membrane potential increased the intracellular Cl- activity; currents that hyperpolarized this membrane potential decreased the intracellular Cl- activity. These findings are compatible with conductive Cl- transport across the choroidal membrane. The apparent Cl- conductance of this membrane was estimated to be 0.59 mS cm-2. This represents 27% of the total conductance in the choroidal membrane. Administration of 1 mM cAMP and 0.5 mM IBMX caused a 21% increase in the apparent Cl- conductance of the choroidal membrane.     

A new isolation procedure for retinal pigment epithelium

A new isolation procedure for bovine retinal pigment epithelial cells has been developed. It is based on perfusion of the whole bovine eye via the central ophthalmic artery with a cold, buffered isotonic salt solution free of divalent cations for 15 min. The perfusion both weakens the association of the pigment epithelial cells with Bruch's membrane and the adhesion between retina and pigment epithelium. The retina then is removed carefully, after which the pigment epithelial cells are detached from the Bruch's membrane by gentle jets of buffer solution. The perfusion technique provides a high yield of intact retinal pigment epithelial cells, which show good viability in subsequent cell culture. Hence, cells isolated in this way are not only very well suited for long-term cell culture but also for direct biochemical analysis and short-term incubation studies.