Corneal endothelial cell loss after trabeculectomy and phacoemulsification in one or two steps: a prospective study.

OBJECTIVE: The objective of this study was to analyse the results of the surgical treatment of coexisting cataract and glaucoma and its effects on corneal endothelial cell density (CECD). METHODS: We include two longitudinal prospective studies: one randomised that included 40 eyes with open angle glaucoma that received one- (n = 20) or two-step (n = 20) phacotrabeculectomy and another that included 20 eyes that received phacoemulsification. We assess the impact of surgery on different clinical variables and in particular in CECD using Confoscan 4™ confocal microscopy and semiautomatic counting methods. RESULTS: Phacoemulsification and phacotrabeculectomy, but not trabeculectomy, increase significantly best-corrected visual acuity and anterior chamber depth and trabeculectomy and one- or two-step phacotrabeculectomy decreased similarly the intraocular pressure. We document percentages of endothelial cell loss of 3.1%, 17.9%, 31.6% and 42.6% after trabeculectomy, phacoemulsification and one- or two-step phacotrabeculectomy, respectively. The coefficient of variation did not increase significantly after surgery but the percentage of hexagonality decreased significantly after phacoemulsification and after two-step phacotrabeculectomy. CONCLUSIONS: Trabeculectomy, phacoemulsification and phacotrabeculectomy are surgical techniques that cause morphological changes and decrease the densities of the corneal endothelial cells. Trabeculectomy produces lesser endothelial cell loss than phacoemulsification, and phacoemulsification lesser cell loss than phacotrabeculectomy. Two-step phacotrabeculectomy (trabeculectomy followed 3 months later by phacoemulsification) causes more cell loss than one-step phacotrabeculectomy, and this could be due to the cumulative effects of two separate surgical traumas or to a negative conditioning lesion effect of the first surgery. For the treatment of coexisting glaucoma and cataract, one-step phacotrabeculectomy is the treatment of choice.

Different Ipsi- and Contralateral Glial Responses to Anti-VEGF and Triamcinolone Intravitreal Injections in Rats.

PURPOSE: To investigate the glial response of the rat retina to single or repeated intravitreal injections (IVI). METHODS: Albino Sprague-Dawley rats received one or three (one every 7 days) IVI of anti-rat VEGF (5 µL; 0.015 µg/µL), triamcinolone (2.5 or 5 µL; 40 µg/µL; Trigón Depot), bevacizumab (5 µL; 25 µg/µL; Avastin), or their vehicles (PBS and balanced salt solution) and were processed 7 days after the last injection. Retinas were dissected as whole mounts and incubated with antibodies against: Iba1 (Ionized Calcium-Binding Adapter Molecule 1) to label retinal microglia, GFAP (Glial Fibrillary Acidic Protein) to label macroglial cells, and vimentin to label Müller cells. The retinas were examined with fluorescence and confocal microscopy, and the numbers of microglial cells in the inner retinal layers were quantified using a semiautomatic method. RESULTS: All the injected substances caused an important micro- and macroglial response locally at the injection site and all throughout the injected retina that was exacerbated by repeated injections. The microglial response was also observed but was milder in the contralateral noninjected eyes. The IVI of the humanized antibody bevacizumab caused a very strong microglial reaction in the ipsilateral retina. Two types of macroglial response were observed: astrocyte hypertrophy and Müller end-foot hypertrophy. While astrocyte hypertrophy was widespread throughout the injected retina, Müller end-foot hypertrophy was localized and more extensive with triamcinolone use or after repeated injections. CONCLUSIONS: Intravitreal injections cause micro- and macroglial responses that vary depending on the injected agent but increase with repeated injections. This inflammatory glial response may influence the effects of the injected substances on the retina.

Comparative study of human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC) as a treatment for retinal dystrophies.

Retinal dystrophies (RD) are major causes of familial blindness and are characterized by progressive dysfunction of photoreceptor and/or retinal pigment epithelium (RPE) cells. In this study, we aimed to evaluate and compare the therapeutic effects of two pluripotent stem cell (PSC)-based therapies. We differentiated RPE from human embryonic stem cells (hESCs) or human-induced pluripotent stem cells (hiPSCs) and transplanted them into the subretinal space of the Royal College of Surgeons (RCS) rat. Once differentiated, cells from either source of PSC resembled mature RPE in their morphology and gene expression profile. Following transplantation, both hESC- and hiPSC-derived cells maintained the expression of specific RPE markers, lost their proliferative capacity, established tight junctions, and were able to perform phagocytosis of photoreceptor outer segments. Remarkably, grafted areas showed increased numbers of photoreceptor nuclei and outer segment disk membranes. Regardless of the cell source, human transplants protected retina from cell apoptosis, glial stress and accumulation of autofluorescence, and responded better to light stimuli. Altogether, our results show that hESC- and hiPSC-derived cells survived, migrated, integrated, and functioned as RPE in the RCS rat retina, providing preclinical evidence that either PSC source could be of potential benefit for treating RD.

Changes in the inner and outer retinal layers after acute increase of the intraocular pressure in adult albino Swiss mice.

In adult albino mice the effects of increased intraocular pressure on the outer retina and its circuitry was investigated at intervals ranging 3-14 weeks. Ocular hypertension (OHT) was induced by cauterizing the vessels draining the anterior part of the mice eye, as recently reported (Salinas-Navarro et al., 2009a). Electroretinographic (ERG) responses were recorded simultaneously from both eyes and compared each other prior to and at different survival intervals of 2, 8 or 12 weeks after lasering. Animals were processed at 3, 9 or 14 weeks after lasering, and radial sections were obtained in the cryostat and further processed for immunocytochemistry using antibodies against recoverin, gamma-transducin, Protein Kinase C-alpha (PKC-alpha), calbindin or synaptophysin. The synaptic ribbons were identified using an antibody against the protein bassoon, which labels photoreceptor ribbons and nuclei were identified using TO-PRO. Laser photocoagulation of the perilimbar and episcleral veins of the left eye resulted in an increase in mean intraocular pressure to approximately over twice its baseline by 24 h that was maintained for approximately five days reaching basal levels by 1 week. ERG recordings from the different groups of mice showed their a-, b-wave and scotopic threshold response (STR) amplitudes, when compared to their contralateral fellow eye, reduced to 62%, 52% and 23% at 12 weeks after lasering. Three weeks after lasering, immunostaining with recoverin and transducin antibodies could not document any changes in the outer nuclear layer (ONL) but both ON-rod bipolar and horizontal cells had lost their dendritic processes in the outer plexiform layer (OPL). Sprouting of horizontal and bipolar cell processes were observed into the ONL. Fourteen weeks after lasering, protein kinase-C antibodies showed morphologic changes of ON-rod bipolar cells and calbindin staining showed abnormal horizontal cells and a loss of their relationship with their presynaptic input. Moreover, at this time, quantitative studies indicate significant diminutions in the number of photoreceptor synaptic ribbons/100 microm, and in the thickness of the outer nuclear and plexiform layer, when compared to their fellow eyes. Increased intraocular pressure in Swiss mice results in permanent alterations of their full field ERG responses and in changes of the inner and outer retinal circuitries.