Hypothermia Promotes Survival of Ischemic Retinal Ganglion Cells.

PURPOSE: Ischemic stroke in retinal arteries leads to death of neural tissue and ultimately to blindness. The retina is known to die within 4 hours after onset of ischemia. It is debated whether hypothermia might increase the time window for medical treatment and thereby the chance of recovering sight. In order to characterize the time course of cell death during ischemia and potential beneficial effects of hypothermia in more detail, we investigated the survival of ganglion cells in ischemic pig and human retina as a function of time and temperature. METHODS: Eyes were obtained from minipigs and from human donors post mortem. Enucleated minipig eyes were stored for defined durations at three different temperatures (37 °C, 21 °C, and 4 °C). In order to assess the viability of the tissue, we measured ganglion cell activity (spiking) with multielectrode arrays. RESULTS: Minipig retinal ganglion cell function was severely compromised after 2 hours of ischemia at body temperature. After 4 hours, ganglion cells did not fire action potentials anymore. However, at 21 °C, ganglion cell activity was maintained under ischemic conditions for up to 12 hours, and for at least 50 hours at 4 °C. In postmortem human retina, we recorded ganglion cell activity in retinas received up to 27 hours after death. CONCLUSIONS: Our results demonstrate that hypothermia greatly increases survival of retinal ganglion cells exposed to ischemia. These results might be relevant for the future treatment of retinal ischemia.

Toxic effects of melphalan, topotecan and carboplatin on retinal pigment epithelial cells.

PURPOSE: Clinical evidence of retinal pigment epithelium (RPE) alterations after intra-arterial (IAC) and intravitreal chemotherapy (IViC) of retinoblastoma has been reported. We, therefore, investigated the cellular toxic effects of melphalan, topotecan and carboplatin on the RPE in a cell culture model. METHODS: The effects of melphalan, carboplatin and topotecan on ARPE19 cell morphology were examined by phase contrast microscopy. Cell proliferation was quantified by BrdU incorporation, cell viability studied via MTS assays, and cell densities were estimated by Crystal Violet staining, and apoptosis induction studied via caspase 3/7-activity assays after a 24-hr incubation period. Staurosporine, media without fetal bovine serum, diluents of melphalan, carboplatin and topotecan were applied as positive and negative controls, respectively. RESULTS: We observed a concentration-dependent increase in the number and size of gaps in the ARPE19 cell layer with each drug. There was a significant decrease in proliferative activity and cell viability of RPE cells as well as an increase in apoptosis after 24 hrs culture in media supplemented with melphalan and topotecan. Carboplatin had comparable effects on cell proliferation and cell viability; however, no significant apoptotic impacts were observed. The three cytostatic drugs had insignificant effects on cell density measurements. CONCLUSIONS: Morphological monitoring and toxicity assays indicate a direct toxic effect of melphalan and the other two cytostatic drugs on ARPE19 cells. Thus, a direct toxic effect of melphalan in vivo after IAC or IViC on the RPE seems probable and may explain the clinical and angiographic RPE alterations observed in some retinoblastoma patients.

Cataract formation: a possible complication of intra-arterial chemotherapy for retinoblastoma.

PURPOSE: To delineate and discuss a not yet described possible ocular complication of selective intra-arterial chemotherapy (SIAC) for treatment of retinoblastoma. METHODS: A 23-month-old girl with a large unilateral retinoblastoma was treated with repeated SIAC using 5 mg melphalan between July 2010 and January 2012. Clinical course of tumor and further ocular changes after therapy and histopathologic findings are described. RESULTS: In total, 5 SIAC were performed over a time period of 18 months. After the last SIAC, diffuse dense cataract prevented further funduscopy. In addition, anterior chamber seeding was obvious, leading to the decision to enucleate the eye. Histopathologically, nearly complete regression of the main tumor mass with prominent calcifications, but vital tumor seeding in the vitreous, on the lens surface, on the ciliary body, and in the anterior chamber, was observed. Peculiar vacuolation of the lens epithelial cells, liquefaction of the subepithelial lens fibers, and diffuse small vacuoles within the lens were striking. CONCLUSIONS: Repeated SIAC with melphalan may induce cataract formation, possibly as a toxic effect of the chemotherapeutic to the lens, maybe combined with radiation exposure during fluoroscopy. This ocular complication should be taken into consideration as a limitation of the number of feasible repeated treatments.

Pars plana vitrectomy for treatment of advanced Coats' disease--presentation of a modified surgical technique and long-term follow-up.

BACKGROUND: To present a modified surgical technique in the treatment of retinal detachment secondary to advanced Coats' disease in children, and report on long-term anatomical and functional outcome. METHODS: We analysed an interventional case series of 13 patients (13 eyes) with advanced Coats' disease characterised by retinal detachment in addition to massive subretinal exudates and vascular malformation. The presented patients underwent pars plana vitrectomy (PPV), including a modified technique of exocryotherapy applied after fluid-air exchange in order to achieve complete treatment of the vascular changes, to reduce associated side-effects, and to avoid retinectomy and silicone oil tamponade. RESULTS: Within a median follow-up period of 37 months (range: 18-66 months), no enucleation was necessary. Four eyes (31 %) did not need any further therapy, and in nine eyes (69 %) additional treatments were performed. Six patients (46 %) required revisional surgery with silicone oil tamponade. In ten eyes (77 %), the pathologic vessels and exudates finally regressed and the retina reattached. Visual acuity (VA) could be stabilized in the majority of patients: in three eyes (27 %) VA improved, in four eyes (36 %) VA remained stable, in four eyes (36 %) visual acuity (VA) deteriorated, and in two eyes VA could not be evaluated. CONCLUSIONS: The presented modified technique allows for sufficient cryotherapy of vascular malformations, even in the presence of massive exudation, in a subset of patients with advanced Coats' disease, and thus may reduce surgery-related complications and improve the rehabilitation process of these young patients.