Effects of argon laser iridotomy on the corneal endothelium of pigmented rabbit eyes

Clinical Efficacy of Iris Cystostomy Using a Yttrium Aluminum Garnet Laser

Purpose: To report the clinical efficacy of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser iris cystotomy in iris cysts.Methods: We examined three eyes with primary iris cysts diagnosed by ultrasound biomicroscopy that had fewer cornea endothelial cells or reduced visual acuity due to an occluded visual axis. Nd:YAG laser cystotomy was done. The logarithm of the minimum angle of resolution (logMAR) visual acuity, intraocular pressure (IOP), and specular microscopy test at baseline and last follow-up were reviewed.Results: The average patient age was 54.0 ± 5.3 years; the mean follow-up was 11.7 ± 2.1 months. The baseline and final logMAR visual acuity were 0.23 ± 0.25 and 0.16 ± 0.15, respectively. Visual acuity improved, although not significantly (p = 0.317). The baseline and final IOP were 14.7 ± 2.3 and 13.7 ± 0.6 mmHg, respectively (p = 0.276). The corneal endothelial cell density (p = 0.109), hexagonality (p > 0.999), and coefficient of variation (p = 0.285) were not significantly different after treatment. There were no serious complications or recurrence.Conclusions: After Nd:YAG laser cystotomy, the cell density and morphology of corneal endothelial cells changed little. It can be considered an effective treatment when there is a decrease in corneal endothelial cells or occlusion of the visual axis.

Matrigel and Activin A promote cell-cell contact and anti-apoptotic activity in cultured human retinal pigment epithelium cells

Age-related macular degeneration (AMD) is a leading cause of blindness among the aging population. Currently, replacement of diseased retinal pigment epithelium (RPE) cells with transplanted healthy RPE cells could be a feasible approach for AMD therapy. However, maintaining cell-cell contact and good viability of RPE cells cultured in vitro is difficult and fundamentally determines the success of RPE cell transplantation. This study was conducted to examine the role of Matrigel and Activin A (MA) in regulating cell-cell contact and anti-apoptotic activity in human RPE (hRPE) cells, as assessed by atomic force microscopy (AFM), scanning electron microscope (SEM), immunofluorescence staining, quantitative polymerase chain reaction (qPCR) analysis, Annexin V/propidium iodide (PI) analysis, mitochondrial membrane potential (△Ψ m) assays, intracellular reactive oxygen species (ROS) assays and Western blotting. hRPE cells cultured in vitro could maintain their epithelioid morphology after MA treatment over at least 4 passages. The contact of N-cadherin to the lateral cell border was promoted in hRPE cells at P2 by MA. MA treatment also enhanced the expression of tight junction-associated genes and proteins, such as Claudin-1, Claudin-3, Occludin and ZO-1, as well as polarized ZO-1 protein distribution and barrier function, in cultured hRPE cells. Moreover, MA treatment decreased apoptotic cells, ROS and Bax and increased △Ψ m and Bcl2 in hRPE cells under serum withdrawal-induced apoptosis. In addition, MA treatment elevated the protein expression levels of β-catenin and its target proteins, including Cyclin D1, c-Myc and Survivin, as well as the gene expression levels of ZO-1, β-catenin, Survivin and TCF-4, all of which could be down-regulated by the Wnt/β-catenin pathway inhibitor XAV-939. Taken together, MA treatment could effectively promote cell-cell contact and anti-apoptotic activity in hRPE cells, partly involving the Wnt/β-catenin pathway. This study will benefit the understanding of hRPE cells and future cell therapy.

The effects of proinflammatory cytokines on the apoptosis of corneal endothelial cells following argon laser iridotomy

The aim of this study was to evaluate the relationship between the expression of proinflammatory cytokines and the apoptosis of corneal endothelial cells after argon laser iridotomy (ALI). ALI was performed on each quadrant of the iris in the right eye of mice (ALI1 group). Left eyes were used as control group. The levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and interferon (IFN)-γ in mice eyes were measured, and TUNEL staining was performed 12 h after ALI. Mice in the ALI-Dexa group were pretreated daily with an intraperitoneal injection of dexamethasone for 4 days before undergoing ALI and compared with mice without dexamethasone pretreatment (ALI2 group). Twelve corneas from six rabbits were incubated ex vivo with (n = 6) or without (n = 6) IL-1β. TUNEL staining was performed 24 h after ex vivo incubation. In the mice experiment, the levels of IL-1β, TNF-α, TGF-β, and IFN-γ were increased in the ALI1 group compared to the control group. Although many TUNEL-positive cells were observed in the ALI1 group, those were not detected in the control group. Dexamethasone pretreatment inhibited the increase in the levels of all four proinflammatory cytokines and reduced TUNEL-positive cells. In the rabbit experiment, TUNEL-positive cells were increased in the incubated corneas with IL-1β compared to those without IL-1β. Expression of proinflammatory cytokines following ALI seems to play a role in the apoptosis of corneal endothelial cells after ALI. Dexamethasone pretreatment inhibited increases in proinflammatory cytokines and reduced the apoptosis of corneal endothelial cells.