Revisiting the role of erythropoietin for treatment of ocular disorders.

Erythropoietin (EPO) is a glycoprotein hormone conventionally thought to be responsible only in producing red blood cells in our body. However, with the discovery of the presence of EPO and EPO receptors in the retinal layers, the EPO seems to have physiological roles in the eye. In this review, we revisit the role of EPO in the eye. We look into the biological role of EPO in the development of the eye and the physiologic roles that it has. Apart from that, we seek to understand the mechanisms and pathways of EPO that contributes to the therapeutic and pathological conditions of the various ocular disorders such as diabetic retinopathy, retinopathy of prematurity, glaucoma, age-related macular degeneration, optic neuritis, and retinal detachment. With these understandings, we discuss the clinical applications of EPO for treatment of ocular disorders, modes of administration, EPO formulations, current clinical trials, and its future directions.

Safety and Efficacy of Human Wharton's Jelly-Derived Mesenchymal Stem Cells Therapy for Retinal Degeneration.

PURPOSE: To investigate the safety and efficacy of subretinal injection of human Wharton's Jelly-derived mesenchymal stem cells (hWJ-MSCs) on retinal structure and function in Royal College of Surgeons (RCS) rats. METHODS: RCS rats were divided into 2 groups: hWJ-MSCs treated group (n = 8) and placebo control group (n = 8). In the treatment group, hWJ-MSCs from healthy donors were injected into the subretinal space in one eye of each rat at day 21. Control group received saline injection of the same volume. Additional 3 animals were injected with nanogold-labelled stem cells for in vivo tracking of cells localisation using a micro-computed tomography (microCT). Retinal function was assessed by electroretinography (ERG) 3 days before the injection and repeated at days 15, 30 and 70 after the injection. Eyes were collected at day 70 for histology, cellular and molecular studies. RESULTS: No retinal tumor formation was detected by histology during the study period. MicroCT scans showed that hWJ-MSCs stayed localised in the eye with no systemic migration. Transmission electron microscopy showed that nanogold-labelled cells were located within the subretinal space. Histology showed preservation of the outer nuclear layer (ONL) in the treated group but not in the control group. However, there were no significant differences in the ERG responses between the groups. Confocal microscopy showed evidence of hWJ-MSCs expressing markers for photoreceptor, Müller cells and bipolar cells. CONCLUSIONS: Subretinal injection of hWJ-MSCs delay the loss of the ONL in RCS rats. hWJ-MSCs appears to be safe and has potential to differentiate into retinal-like cells. The potential of this cell-based therapy for the treatment of retinal dystrophies warrants further studies.

Osteo-odonto-keratoprosthesis for end-stage cornea blindness.

We report the first case of Osteo-odonto-keratoprosthesis (OOKP) who successfully underwent surgery in Malaysia following a grade 4 (severe) chemical injury in both eyes in 2006. The patient's left eye was eviscerated and his right eye underwent penetrating keratoplasty. However, the corneal graft failed and became opaque. His right eye could only perceive light. The OOKP was offered to him hoping to recover some functional vision. He underwent a 2-stage surgery to implant the OOKP into his right eye. However, 2 months post-operation, he developed vitreous haemorrhage. A successful pars plana vitrectomy (PPV) was performed via the limited view through the lens. He attained a final visual acuity of 6/60 (N36). He was able to mobilize more independently, feed, dress himself and read large print.

The Adjunctive Use of Anti-vascular Endothelial Growth Factor Agents in the Management of Iris Neovascularisation in Malaysia.

This retrospective study investigated the role of antivascular endothelial growth factor agents (VEGF), ranibizumab, bevacizumab and pegaptanib sodium in patients with iris neovascularisation (INV), in which 9 eyes received intraocular injections for various ischaemic ocular conditions. Ocular sequelae included recurrence of rubeosis (n=2) and hyphaema (n=2). Systemic complication included one case of cerebrovascular accident. INV regressed in all cases from day one. INV recurrence occurred in 2 cases. The mean intraocular pressure of the study eyes decreased from 25.3 mmHg to 18.3 mmHg at one month. Five eyes are medication free. Visual acuity improved in 5 eyes. Four eyes achieved a Snellen visual acuity of 6/24 or better. We conclude that the use of intraocular anti-VEGF agents are safe and effective for inducing the regression of INV. Patients with multiple systemic risk factors should be counseled on stroke risk.

Non-destructive mechanical characterisation of UVA/riboflavin crosslinked collagen hydrogels.

AIMS: To establish a non-destructive method of characterising the mechanical properties of collagen hydrogels to model corneal tissue and to examine the effect of photochemical crosslinking on their mechanical properties. METHODS: Collagen hydrogels were manufactured, submerged in 0.1% riboflavin solution and crosslinked using two UVA tube bulbs with an intensity of between 2.8 and 3.2 mW/cm(2). The hydrogels were clamped around their outer edge and deformed using a sphere. The deformation was measured in situ using a long-working-distance microscope connected to a CCD camera, and the deformation displacement was used with a theoretical model to calculate the Young modulus of the hydrogels. Collagen hydrogels seeded with human corneal fibroblasts were used to examine cell viability after UVA irradiation. RESULTS: There was an increase in Young modulus of the collagen hydrogels after UVA/riboflavin treatment that was dependent on the exposure time. UVA irradiation without riboflavin showed decreased mechanical integrity and strength. Cell viability was reduced with increased UVA exposure time. CONCLUSION: The non-destructive technique demonstrated a new methodology comparable with strip extensiometry for cornea or corneal model specimens but with more convenient features. This approach could be used as an initial step in developing new crosslinking treatments for patients with keratoconus.

Generating neuron-like cells from BM-derived mesenchymal stromal cells in vitro.

BACKGROUND: The multipotency of stromal cells has been studied extensively. It has been reported that mesenchymal stromal cells (MSC) are capable of differentiating into cells of multilineage. Different methods and reagents have been used to induce the differentiation of MSC. We investigated the efficacy of different growth factors in inducing MSC differentiation into neurons. METHODS: MSC from human BM were isolated and cultured in media supplemented with 10% FBS. These cells were identified and later induced to differentiate into neuron-like cells using different neurotrophic factors. Three different growth factors were used, either alone or in combination: brain-derived neurotrophic factor, epidermal growth factor and neural growth factor. RESULTS: After 10 days of culture, MSC showed neuron-like morphologic changes. Immunostaining showed that these cells expressed markers for neurons (growth-associated protein-43, neuron-specific nuclear protein and neurofilament 200 kDa) and expression of these markers suggested the transition of immature stages to more mature stages of neuron-like cells. DISCUSSION: Our results show that BM-derived MSC can differentiate not only into target cells of mesodermal origin but also neuron-like cells of ectodermal origin. The findings show that a combination of growth factors is more effective in inducing MSC into neuron-like cells.

Mesenchymal stromal cell-like characteristics of corneal keratocytes.

BACKGROUND: The unique potential of mesenchymal stromal cells (MSC) has generated much research interest recently, particularly in exploring the regenerative nature of these cells. Previously, MSC were thought to be found only in the BM. However, further studies have shown that MSC can also be isolated from umbilical cord blood, adipose tissue and amniotic fluid. In this study, we explored the possibility of MSC residing in the cornea. METHODS: Human cornea tissues were chopped to fine pieces and cultured in DMEM supplemented with 10% FBS. After a few days, the crude pieces of cornea were removed. Isolated keratocytes that were adherent to tissue culture flasks were grown until confluency before being passaged further. The immunophenotype was evaluated by flow cytometry. Assays were performed to differentiate cultured cells into adipocytes and osteocytes. RESULTS: Isolated corneal keratocytes exhibited a fibroblastoid morphology and expressed CD13, CD29, CD44, CD56, CD73, CD90, CD105 and CD133, but were negative for HLA-DR, CD34, CD117 and CD45. These properties are similar to those of BM-MSC (BM-MSC). In addition, corneal keratocytes were able to differentiate into adipocytes and osteocytes. DISCUSSION: Our results indicate that corneal keratocytes have MSC-like properties similar to those of BM-MSC. This study opens up the possibility of using BM-MSC in corneal tissue engineering and regeneration. Furthermore, discarded corneal tissue can also be used to generate MSC for tissue engineering purposes.

Spontaneous eyelid expansion after full thickness eyelid resection and direct closure.

BACKGROUND/AIMS: Direct closure of eyelid defects gives excellent functional results but is usually restricted to defects measuring less than a quarter of the eyelid length for fear of distorting the palpebral aperture and compromising lid function. The authors have used direct closure in larger defects. The aim of this study was to establish the effects of direct closure of full thickness eyelid margin defects under tension on the palpebral aperture dimensions. METHODS: A consecutive series of patients who had undergone one eyelid, full thickness lid resection repaired by direct closure were identified and invited to have both eyes photographed. The palpebral apertures of both eyes were measured from the photographs by a masked observer. The amount of eyelid resected was recorded from the operation notes. The unoperated palpebral aperture was used as the control. The result were analysed using a paired samples t test. RESULTS: The photographs of 18 patients were included in the analysis. The mean width of excised full thickness lid tissue was 15 mm (range 7-26 mm). The mean vertical palpebral aperture height was 9.2 (SD 1.4) mm in the operated eye as opposed to 9.3 (SD 1.2) mm in the non-operated eye. The mean horizontal palpebral aperture width was 26.1 (SD 1.9) mm in the operated eye as opposed to 26.4 (SD 1.8) mm in the non-operated eye. There was no statistically significant difference between the operated and unoperated horizontal and vertical palpebral measurements. CONCLUSIONS: Direct closure of large full thickness eyelid defects is possible in selected patients with excellent functional and cosmetic results. Eyelid tissue expansion occurs spontaneously following direct eyelid defect closure under tension, restoring the palpebral aperture dimensions.