Mitsuyasu Moriwaki

Hepatocyte growth factor stimulates proliferation and migration during wound healing of retinal pigment epithelial cells in vitro

PURPOSE A defect in retinal pigment epithelial (RPE) cells may cause dysfunction of the neural retina, so rapid recovery of differentiated RPE cells is required after RPE injury. We investigated the effect of hepatocyte growth factor (HGF) on wound healing in RPE cells. METHODS Confluent monolayers of bovine RPE cells were denuded, and the cells were allowed to recover in the presence or absence of HGF. The effect of HGF on RPE cell proliferation was evaluated by a 3-(4;5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetraz olium assay. In a migration assay, mitomycin C was used to inhibit proliferation, and the number of migrated cells was counted. The signaling pathways involved were examined using inhibitors of mitogen-activated protein kinase (MAPK), phosphatidylinositol-3 (PI3) kinase and protein kinase C pathways. RESULTS At 80 ng/mL, HGF stimulated the wound closure of RPE monolayers and rendered the restituted cells more epithelioid in shape. HGF at 10 ng/mL stimulated RPE cell migration the most, whereas 80 ng/mL of HGF inhibited migration, but stimulated proliferation the most. In particular, PI3 kinase and MAPK inhibitor inhibited PRE cell migration and proliferation, respectively. CONCLUSIONS HGF stimulated wound closure in cultured RPE cells, and rendered restituted cells epithelioid in shape. HGF may become a therapeutic candidate for RPE wound healing.

Retinal sensitivity measurement over drusen using scanning laser ophthalmoscope microperimetry.

Abstract · Background: Retinal sensitivity over drusen was examined using a scanning laser ophthalmoscope to confirm a previous report of no change in sensitivity over drusen. · Methods: Microperimetry was performed using a scanning laser ophthalmoscope in 23 eyes of 19 subjects. Subject age ranged from 42 to 86 years (mean 68.5 years). Fifty-four drusen bigger than the diameter of a major retinal vein at the optic disc rim were examined, and drusen were classified as soft drusen and other large drusen. · Results: Nine eyes of eight subjects showed a decrease in retinal sensitivity over drusen. The decrease in retinal sensitivity was more than 5 dB less than the sensitivity at a peripheral non-drusen area peripheral to the measurement point. The sensitivity decrease was noted over 15 of 29 large drusen and the decrease was statistically significant (P<0.02). However, no relationship between the size of the drusen and the amount by which sensitivity decreased was found. Nevertheless, a decrease in retinal sensitivity was not seen over any of 25 soft drusen. · Conclusion: Large drusen may influence retinal sensitivity and function.

Long-term follow-up of severe central serous chorioretinopathy using indocyanine green angiography

Background: The severe types of central serous chorioretinopathy (CSC) have a chronic nature, suggesting that a pathological process persists subclinically. Indocyanine green(ICG) angiography recently revealed intrachoroidal dye leakage and its static nature in CSC. As the intrachoroidal dye leakage was suspected to be relevant to the disease process, the long-term persistence of intrachoroidal ICG leakage was examined in four patients of the severe types of CSC. Methods: ICG angiography was performed periodically over more than three years in three patients and two years in one patient. One patient had CSC with bullous retinal detachment, and the other three had chronic CSC or diffuse retinal pigment epitheliopathy. Results: Intrachoroidal ICG leakage persisted in all the patients. However, a change in location of persistent intrachoroidal leakage or disappearance of intrachoroidal leakage regardless of no progression of retinal pigment epithelial alteration was noted in one eye of two patients. Conclusions:Pathology causing intrachoroidal ICG leakage persisted subclinically for a long period. However, location and extent of the intrachoroidal leakage could change during along-term follow-up period.

Fundus autofluorescence in patients with pseudoxanthoma elasticum.

Purpose: To characterize changes in fundus autofluorescence in patientswith pseudoxanthoma elasticum (PXE). Fundus autofluorescence intrinsicallyderives from lipofuscin, and the degree of autofluorescence is thought to indicatethe degree of retinal pigment epithelium (RPE) metabolic activity. Methods:Twelve eyes of 6 patients (2 men, 4 women) with PXE were studied with aconfocal scanning laser ophthalmoscope. Patient age ranged from 42 to 62years. The autofluorescence of abnormal retinal areas was compared digitallywith that of neighboring, presumed healthy control areas. When the averagegray level of a fundus region was 2 SDs above or below the average graylevel of a control area, autofluorescence of the fundus region was consideredabnormal. Results: In all 12 eyes, some segments of the angioid streaksshowed decreased fundus autofluorescence, and other segments of the streaksshowed normal autofluorescence. Areas of peripapillary chorioretinal atrophyseen in 2 eyes and of disciform scarring seen in 3 eyes showed decreasedautofluorescence. Solitary or multiple drusen-like spots showed increasedautofluorescence in all 12 eyes. Conclusion: Atrophic and degenerativeRPE regions showed decreased fundus autofluorescence in areas of chorioretinalatrophy and in some segments of the angioid streaks. Some drusen-like spotsshowed increased autofluorescence. The characteristic changes in autofluorescencethat we observed in PXE patients suggest that the content of the drusen-like substancediffers from that of senile drusen and that the drusen-like lesions are similar to thesub-RPE deposits seen in macular dystrophy.

Effect of Retinoic Acid on Proliferation and Polyamine Metabolism in Cultured Bovine Retinal Pigment Epithelial Cells

Reports regarding the effect of all-trans-retinoic acid (RA) on the cell growth of retinal pigment epithelial cells (RPE) have been contradictory. The aims of this study are to clarify the in vitro effect of RA on RPE cells and to examine polyamine metabolism after RA stimulation. A 4-day incubation of fetal-calf-serum (FCS)-stimulated RPE cells with 10 or 25 µM RA significantly increased both cell number and [3H]thymidine incorporation. RPE cells grown over an extended period for 8 days also increased in number and reached full confluency. However, if the incubation was further extended to 12 days, no further increase in cell number was detected. RA treatment of FCS-stimulated RPE cells shifted the peak of ornithine decarboxylase (ODC) activity from 16 to 4 h. S-adenosylmethionine decarboxylase (SAMDC) activity and spermidine/spermine N1-acetyltransferase (SAT) activity of RA-treated RPE cells were significantly greater until 8 and 16 h after incubation, respectively. The putrescine content was significantly increased in RA-treated RPE cells up until 24 h, while spermidine, spermine and N1-acetylspermidine contents were significantly increased until 16 h. Our findings suggest that RA treatment increases the intracellular polyamine concentration of RPE cells via activation of ODC, SAMDC and SAT and that this results in the promotion of RPE cell growth until the cells reach full confluency.

Acute retinal necrosis late in the second trimester

PURPOSE To report treatment of a patient with acute retinal necrosis during pregnancy. METHODS A 24-year-old woman in her twenty-third week of gestation was diagnosed with acute retinal necrosis. A combination of acyclovir and interferon therapy was started at 25 weeks. Pars plana vitrectomy was performed during the 26th week of gestation. RESULTS The necrotizing retina became gliotic within 3 weeks of surgery. The patients visual acuity improved to LE, 20/40. A healthy baby was delivered at 39 weeks of gestation. CONCLUSION Combination therapy of acyclovir and interferon followed by surgery partially restored the patients vision without affecting fetal development.

Computer assisted image analysis using the subtraction method in indocyanine green angiography

The choroidal vessels are three dimensionally distributed and very complex in their patterns. They often appear to be overlaid in indocyanine green (ICG) angiograms so it is harder to analyze ICG angiography than fluorescein angiography. When an earlier frame is subtracted from a later frame in a sequence of angiograms, the fluorescence which has increased during the time between the two frames can theoretically be demonstrated. We applied computer-assisted image subtraction methods in selected clinical cases of directly acquired digital ICG angiography to demonstrate how this method works. We used software already installed in an IMAGEnet computer system (Topcon) for image subtraction. We applied the subtraction technique in 18 cases with various diseases. When two images with a time difference of several seconds were subtracted, filling of the choriocapillaris, the neovascularization or the pathological vessels could be observed. When the images had a time difference of several minutes, intrachoroidal dye leakage could be seen more clearly. This method is very helpful for analyzing pathological changes in ICG angiography in clinical cases, when two images are selected appropriately.

Effect of travoprost on 24-hour intraocular pressure in normal tension glaucoma

Purpose: The effect of travoprost 0.004% on 24-hour intraocular pressure (IOP) was examined in patients with normal tension glaucoma (NTG). Subjects and methods: This study included 17 patients with newly diagnosed unilateral NTG. IOP was measured at three-hour intervals over 24 hours by Goldman applanation tonometer in patients taking topical travoprost 0.004% and was compared retrospectively with 24-hour IOP data in untreated eyes. Results: IOP values were significantly reduced at individual time points after treatment (P < 0.01). Mean 24-hour IOP, maximum 24-hour IOP, minimum 24-hour IOP, and 24-hour IOP fluctuations at baseline (mean ± SD) were 12.9 ± 2.2 mmHg, 15.4 ± 2.7 mmHg, 10.5 ± 2.2 mmHg, and 4.9 ± 1.2 mmHg, respectively, and were significantly reduced to 10.3 ± 2.0 mmHg, 12.4 ± 2.5 mmHg, 8.5 ± 1.9 mmHg (all P < 0.001), and 3.9 ± 1.5 mmHg (P < 0.05), respectively, after treatment. The rate of IOP reduction greater than 20% was 58.8% (10 eyes) for maximum 24-hour IOP and 53.0% (nine eyes) for mean 24-hour IOP. Conclusion: Travoprost reduced IOP throughout the 24-hour study period, with over half of the eyes examined showing IOP reduction exceeding 20%.

Age-related scattered hypofluorescent spots on late-phase indocyanine green angiograms

Purpose: Scattered hypofluorescent spots may be seen on indocyanine green (ICG) angiograms of regions that do not show abnormalities when viewed with an ophthalmoscope. Hypofluorescent spots are found in several pathologic conditions, typically in inflammatory diseases. In this report, we describe hypofluorescent spots in normal fundi and show that such spots can be age-related.Methods: Video-fundus camera ICG angiograms of 115 eyes of 109 patients aged 12 to 85 years with normal fundi or with only age-related maculopathy were reviewed. The relation between age and scattered hypofluorescent spots, and between age-related maculopathy and spots was examined utilising regression analysis.Results: Scattered hypofluorescent spots were seen throughout the posterior pole in 24 eyes of 23 patients and in a portion of the posterior pole in 30 eyes of 29 patients. The hypofluorescent spots were noted between 26 and 37 minutes after dye injection. Patient age ranged from 51 to 80 years, and regression analysis showed that the frequency of hypofluorescent spots increased significantly with aging (p < 0.05). However, age-related maculopathy did not show a significant relation to the spots.Conclusion: Scattered hypofluorescent spots seen in the posterior pole during the late-phase of ICG angiograms can apparently be due to aging of the fundus.

Indocyanine green angiography in choriocapillary atrophy induced by sodium iodate

Abstract•Background: The interpretation of indocyanine green (ICG) angiograms is uncertain in many aspects. We performed a study to examine the involvement of the choriocapillaris (CC) in the late phase of ICG angiography. •Methods: An animal model of chorioretinal atrophy prepared by means of injection of sodium iodate 4 months previously was used. The findings of ICG angiography and histological analysis were compared. • Results: In the late phase of ICG angiography, three fluorescence patterns were observed: the normal region with diffuse ICG fluorescence, a hypofluorescent region with no diffuse fluorescence, and a region with a mixture of hypofluorescence and bright fluorescence. Histological analysis revealed that there were normal CC endothelial cells bearing fenestrae in the region of normal fluorescence. In the region of hypofluorescence, the CC was almost completely obstructed and remnants of capillaries contained thick cytoplasm and lacked fenestrae. In the mixed region of hypofluorescence and bright fluorescence, the CC was partially obstructed and thickened endothelial cells formed intercellular junction complexes by overlapping each other in a complicated manner. Amorphous substances were deposited in some parts of the choroidal interstitium. • Conclusion: The CC may play some role in generating diffuse fluorescence in the late phase of ICG angiography, and the findings of hypofluorescence and bright fluorescence may be related to CC obstruction and increased permeability of abnormal vessels, respectively.