PurposeTo 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.MethodsRCS 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.ResultsNo 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.ConclusionsSubretinal 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.

The aim of this study was to measure and compare the effect of topical insulin (0.5 units, 4 times per day) versus artificial tears (Vismed, sodium hyaluronate 0.18%, 4 times per day) for the healing of postoperative corneal epithelial defects induced during vitreoretinal surgery in diabetic patients.Methods: This is a double-blind randomized controlled hospitalbased study involving diabetic patients with postoperative corneal epithelial defects after vitreoretinal surgery. Diabetic patients were randomized into 2 different groups and received either 0.5 units of topical insulin (DTI) or artificial tears (Vismed, sodium hyaluronate 0.18%; DAT). The primary outcome measured was the rate of corneal epithelial wound healing (mm 2 /h) over a preset interval and time from baseline to minimum size of epithelial defect on fluorescein-stained anterior segment digital camera photography. The secondary outcome measured was the safety of topical insulin 0.5 units and artificial tears (Vismed, sodium hyaluronate 0.18%). Patients were followed up until 3 months postoperation.Results: A total of 38 eyes from 38 patients undergoing intraoperative corneal debridement during vitreoretinal surgery with resultant epithelial defects (19 eyes per group) were analyzed. DTI was observed to have a significantly higher healing rate compared with the DAT group at rates over 36 hours (P = 0.010), 48 hours (P = 0.009), and 144 hours (P = 0.009). The rate from baseline to closure was observed to be significantly higher in the DTI group (1.20 6 0.29) (mm 2 /h) compared with the DAT group (0.78 6 0.20) (mm 2 /h) as well (P , 0.001). No adverse effect of topical insulin and artificial tears was reported.Conclusions: Topical insulin (0.5 units, 4 times per day) is more effective compared with artificial tears (Vismed, sodium hyaluronate 0.18%, 4 times per day) for the healing of postoperative corneal epithelial defects induced during vitreoretinal surgery in diabetic patients, without any adverse events.

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Ocular microbial infection has emerged as a major public health crisis during the past two decades. A variety of causative agents can cause ocular microbial infections; which are characterized by persistent and destructive inflammation of the ocular tissue; progressive visual disturbance; and may result in loss of visual function in patients if early and effective treatments are not received. The conventional therapeutic approaches to treat vision impairment and blindness resulting from microbial infections involve antimicrobial therapy to eliminate the offending pathogens or in severe cases; by surgical methods and retinal prosthesis replacing of the infected area. In cases where there is concurrent inflammation, once infection is controlled, anti-inflammatory agents are indicated to reduce ocular damage from inflammation which ensues. Despite advances in medical research; progress in the control of ocular microbial infections remains slow. The varying level of ocular tissue recovery in individuals and the incomplete visual functional restoration indicate the chief limitations of current strategies. The development of a more extensive therapy is needed to help in healing to regain vision in patients. Stem cells are multipotent stromal cells that can give rise to a vast variety of cell types following proper differentiation protocol. Stem cell therapy shows promise in reducing inflammation and repairing tissue damage on the eye caused by microbial infections by its ability to modulate immune response and promote tissue regeneration. This article reviews a selected list of common infectious agents affecting the eye; which include fungi; viruses; parasites and bacteria with the aim of discussing the current antimicrobial treatments and the associated therapeutic challenges. We also provide recent updates of the advances in stem cells studies on sepsis therapy as a suggestion of optimum treatment regime for ocular microbial infections.