Shoji Kuriyama

Severe Myopia as a Risk Factor for Progressive Visual Field Loss in Primary Open-Angle Glaucoma

The optic nerve head in severely myopic eyes may be particularly vulnerable to glaucomatous damage. To study this hypothesis, we examined 122 primary open-angle glaucoma eyes with fair to good control of the intraocular pressure and a sign of baseline optic nerve damage. Then, parameters for the progression of the visual field defects were evaluated by multivariate analysis. A high mean intraocular pressure (p = 0.007) and a large refractive error (p = 0.023) were significant risk factors for subsequent visual field loss. A high baseline cup-to-disk ratio (p = 0.100) was a marginal risk factor. Nonsignificant parameters included patient age (p = 0.692), the use of beta-adrenergic antagonists (p = 0.384), gender (p = 0.831) and left versus right side (p = 0.977). When the refractive error was used to subclassify patients into severely myopic (< or = -4 dpt), mildly myopic (-0.25 to -4 dpt), or emmetropic and hyperopic (> or = 0 dpt), only severe myopia was a significant risk factor for progressive visual field loss. Severe myopia, but not mild myopia, is a significant risk factor for subsequent visual field loss in patients with primary open-angle glaucoma.

Prognostic Factor Analysis in Pars Plana Vitrectomy for Retinal Detachment Attributable to Macular Hole in High Myopia: A Multicenter Study

PURPOSE To detect the prognostic factors associated with initial reattachment after primary pars plana vitrectomy (PPV) with gas tamponade for retinal detachment attributable to macular hole (MHRD). DESIGN Retrospective, multicenter, interventional case series. METHODS This study included 49 eyes of 48 patients with MHRD in high myopia (axial length more than 28.0 mm). All eyes underwent PPV with gas tamponade. We retrospectively reviewed the medical records and performed univariate analysis to detect the presence of any difference between eyes with a successful initial reattachment and those that failed. We performed multivariate logistic regression analysis to assess the influence of each preoperative factor on initial success. RESULTS Success rate of initial reattachment was 69%. Postoperative best-corrected visual acuity (BCVA) of 34 eyes with initial success was significantly better than those of 15 eyes with initial failure (P < .05); preoperative BCVA was not significantly different (P = .43). The axial length of eyes with initial success (29.26 +/- 0.94 mm) was shorter than that of eyes with initial failure (30.04 +/- 1.49 mm) with borderline significance (P = .049). There were no significant differences noted for other factors such as use of ILM peeling (P = .43) or type of tamponade gas (P = .99). Multiple logistic regression analysis using preoperative factors indicated that only axial length was significantly associated with initial success (odds ratio, 0.49; 95% confidence interval, 0.26 to 0.93; P < .05). CONCLUSIONS Initial reattachment is important for visual prognosis, and axial length is a prognostic factor for initial reattachment after PPV with gas tamponade for MHRD in high myopia.

Outcomes of 23- and 25-gauge transconjunctival sutureless vitrectomies for idiopathic macular holes

Background/aims: To assess the outcomes of 23-gauge sutureless transconjunctival vitrectomies (TSV), as compared with 25-gauge TSV in macular hole surgeries. Methods: A retrospective, consecutive, interventional case series of 47 eyes with idiopathic macular holes treated by 23- or 25-gauge TSV were analysed. Results: The operative time was 37.2 (SD 8.9) min with 23-gauge TSV and 34.2 (8.7) min with 25-gauge TSV (p = 0.388). The anatomical success rate was 96% with 23-gauge TSV and 92% with 25-gauge TSV (p>0.999). The logarithm of the minimum angle of resolution of best-corrected visual acuity (BCVA) at the sixth postoperative month was 0.19 (0.16) with 23-gauge TSV and 0.19 (0.25) with 25-gauge TSV (p = 0.521). Postoperative improvement in BCVA was comparable between the two TSVs. IOP on postoperative day 1 was lower with 25-gauge TSV (12.3 (4.9) mm Hg) than with 23-gauge TSV (17.4 (5.8) mm Hg) (p = 0.036). Complications included retinal break, intraoperative bleeding and slippage of the infusion cannula with 23-gauge TSV, while retinal detachment and postoperative hypotony occurred in the 25-gauge TSV group (p = 0.570). Conclusion: 23-gauge TSV appears to be as safe and effective as 25-gauge TSV in macular hole surgery.

Feasibility of drug targeting to the retinal pigment epithelium with biodegradable microspheres

There are several systems of delivering drugs to cells with phagocytic activity. We studied the possibility of targeting drugs to retinal pigment epithelial (RPE) cells with the use of surface-modified microspheres. A fluorescent dye, 1,4-bis[2-(5-phenyloxazolyl)]-benzene (POPOP), was incorporated into microspheres of poly(lactic acid) for use as a marker to evaluate drug delivery. Phagocytosis of the microspheres, with or without gelatin precoating, was carried out at 37 degrees C and 4 degrees C. The cell-incorporated fluorescence of POPOP was measured, and scanning electron microscopy was used to confirm phagocytosis. At 4 degrees C, no uptake of POPOP was noted; however at 37 degrees C, cell-associated fluorescence was observed to increase for up to 24 hr. In comparison with bare microspheres, gelatin precoating significantly enhanced phagocytosis (P < 0.001) at the same incubation times. These results suggested that drug delivery to RPE cells may be feasible by means of surface-modified polymer microspheres.

Foveal microstructure in macular holes surgically closed by inverted internal limiting membrane flap technique.

Purpose: To evaluate reconstructive foveal anatomical change in surgically closed macular hole (MH) by pars plana vitrectomy with inverted internal limiting membrane flap technique. Methods: Spectral domain optical coherence tomography was used to evaluate foveal microstructures in 20 eyes of 19 patients who underwent pars plana vitrectomy with inverted internal limiting membrane flap technique to achieve MH closure. Eyes had idiopathic large MH with a diameter >500 &mgr;m (n = 7), MH in high myopia (axial length >26.5 mm) without retinal detachment (RD; n = 7), and with RD caused by the MH (n = 6). Results: The 6-month postoperative spectral domain optical coherence tomography examination revealed restoration of the inner segment and outer segment junction in 3 of 7 idiopathic large MH eyes (43%), 2 of 7 highly myopic MH eyes without RD (29%), and 1 of 6 highly myopic MH eyes with RD (17%), and detected the external limiting membrane in 4 of 7 idiopathic large MH eyes (57%), 3 of 7 highly myopic MH eyes without RD (43%), 1 of 6 highly myopic MH eyes with RD (17%). Conclusion: Inverted internal limiting membrane flap technique results in more satisfactory anatomical improvements in patients with idiopathic large MH eyes and highly myopic MH eyes without RD than with highly myopic MH eyes with RD. This might suggest that the foveal photoreceptor layer in MH with RD is destroyed and not recoverable even after retinal reattachment with surgical closure of the MH.

Single-nucleotide polymorphisms in the promoter region of matrix metalloproteinase-1, -2, and -3 in Japanese with high myopia

PURPOSE Polymorphisms in the promoter regions of matrix metalloproteinase (MMP) genes can cause variations in the expression of the MMP genes in the sclera that can lead to a greater susceptibility to axial elongation of the eye. The purpose of this study was to determine whether functional single-nucleotide polymorphisms (SNPs) in the MMP1, -2, and -3 promoter regions are associated with high myopia in the Japanese. METHODS Seven hundred twenty-five unrelated Japanese patients with high myopia (axial length of >or=26.0 mm in both eyes, or refractive error>or=-6.0 D in phakic cases) and >or=40 years of age were studied. Five hundred forty-six healthy, unrelated Japanese who were >or=40 years of age served as population-based control subjects. All the subjects were genotyped for the four functional SNPs MMP1 -1607 1G/2G, MMP2 C-1306T, MMP2 C-735T, and MMP3 -1612 5A/6A with an SNP assay. The distribution of the genotypes in the cases and control subjects was compared by the chi2 test for trend. RESULTS No significant difference was detected in the distribution of the four SNPs MMP1 -1607 1G/2G (P=0.92), MMP2 C-1306T (P=0.83), MMP2 C-735T (P=0.10), and MMP3 -1612 5A/6A (P=0.62), between the high myopia cases and the general-population controls. CONCLUSIONS The four functional SNPs in the MMP1, -2, and -3 promoter regions do not play critical roles in the development of high myopia in the Japanese population.

Neuropeptide-induced cytosolic Ca2+ transients and phosphatidylinositol turnover in cultured human retinal pigment ephithelial cells

Neuropeptide-induced mobilization of cytosolic free Ca2+ concentration ([Ca2+]i) and phosphatidylinositol (PI) turnover in cultured human retinal pigment epithelial (RPE) cells were studied and their temporal relationship was compared. After RPE cells were loaded with fura-2/AM, [Ca2+]i was analyzed using a digital imaging microscopy system. Bombesin-related peptides which include bombesin, neuromedin B, and neuromedin C induced significant [Ca2+]i transients in RPE cells, whereas other neuropeptides, neuropeptide Y, vasoactive intestinal polypeptide (VIP), and substance P were not effective to produce [Ca2+]i transients. The percentage of reactive cells which showed positive [Ca2+]i transients induced by bombesin-related peptides was around 50%. Bombesin (1 microM) showed a peak concentration of 663 +/- 27.0 nM (mean +/- S.E.M., n = 61), neuromedin B (1 microM), 327 +/- 28.7 nM (mean +/- S.E.M., n = 38), and neuromedin C (1 microM), 357 +/- 22.7 nM (mean +/- S.E.M., n = 32). Ca2+ transients occurred within 30 s and lasted less than 5 min after the application of the neuropeptides. Chelation of the extracellular Ca2+ by EGTA significantly shortened the total time of [Ca2+]i transients induced by the above. The measurements of phosphoinositides in RPE cells revealed that neuropeptide-induced PI turnover was as quick as [Ca2+]i transients. Inositol biphosphate (IP2) and inositol triphosphate (IP3) in RPE cells showed transient increases at 15 s after the stimulation by bombesin-related peptides. These data show that changes in [Ca2+]i and PI turnover are directly linked and both are important in the signal transduction system of bombesin-related peptides in RPE cells. The data also suggest that bombesin-related peptides may play some possible roles in RPE cells.

Mass Cultivation of Human Retinal Pigment Epithelial Cells with Microcarrier

Microcarrier cell culture permits mass cultivation of anchorage-dependent cells. In this study, mass cultivation of human retinal pigment epithelial (RPE) cells was studied using Cytodex 3 (Pharmacia) as a microcarrier. Human RPE cells were established from aborted fetuses and cultured in Dulbeccos modified Eagles Medium (DMEM). After the 3rd-5th passages, RPE cells were suspended in 50 ml of DMEM in a spinner flask at a density of 2 x 10(5)/ml, and Cytodex 3 was added to the spinner flask at a bead density of 10 mg/ml. Cultures were maintained at 20-50 rpm (final speed) on a magnetic stirrer, and DMEM was added up to 100 ml. Fifty milliliters of DMEM were decanted and replaced with fresh DMEM every 2 days. After 1 week, a cell density of 10(6)/ml DMEM was obtained. Phase contrast microscopy showed bridging formation between microcarriers, which suggests tight cell adhesion. Microcarrier cell culture has a variety of advantages which include greater cell production, use of less medium and less risk of contamination compared to the conventional monolayer culture technique, and it also allows passaging without using proteases. Using this culture system, greater possibilities for wider application of new cell cultures can be expected.

Nitric Oxide as a Second Messenger in Phagocytosis by Cultured Retinal Pigment Epithelial Cells

Purpose: To investigate a possible role of the nitric oxide (NO)-cGMP signal transduction system in phagocytosis of rod outer segments (ROS) by cultured retinal pigment epithelial (RPE) cells. Methods: Primary cultures of RPE cells from 10-day-old Brown Norway rats were used to study the phagocytosis of ROS by these cells. Phagocytosis of ROS was evaluated with or without an inhibitor of nitric oxide synthase (NOS), NG-nitro-L-arginine (L-NNA), and the reverse effects of L-NNA by L-arginine and 8-bromo-cGMP on phagocytosis were also studied. NO-associated cGMP production by RPE cells was monitored during phagocytosis using L-NNA. NOS activity was assayed in RPE cells and ROS to locate the source of NO. Results: Phagocytosis of ROS was inhibited by L-NNA but not by D-NNA. L-NNA inhibited the ingestion in a dose-dependent manner, but not the binding of ROS. The inhibition was reversed by L-arginine and also by an NO donor, SIN-1. RPE cells challenged with ROS showed increased cGMP activity, which was significantly reduced by L-NNA and again restored by an overdose of L-arginine. NOS activity was found in RPE cells but not in ROS. Conclusions: Our data show that cGMP plays a role in the ingestion phase of ROS phagocytosis by RPE cells via a cGMP second-messenger system.

Surgical techniques and visual prognosis in retinal detachment due to macular hole.

In 250 eyes with retinal detachment due to macular hole, the visual prognosis of each surgical technique was evaluated. (1) Macular diathermy adversely affected the visual prognosis. (2) Macular buckling+macular diathermy produced a poorer visual prognosis than macular buckling alone. (3) The visual prognosis resulting from gas tamponade alone or vitrectomy+gas tamponade was better than that resulting from macular diathermy. It is not clear whether there is a significant difference in visual prognosis between gas tamponade alone and vitrectomy+gas tamponade. (4) Macular laser photocoagulation does not adversely affect the visual prognosis. Judging from these results, gas tamponade, which has the possibility of better visual prognosis and less operation stress, should be selected as the initial technique.