Drusen are important risk factor for neovascular age-related macular degeneration (AMD) and have a dynamic nature as they can enlarge, newly form, or disappear over time. There have been few reports on drusen regression or choroidal neovascularization (CNV) development after macular hole surgery. We report, to our knowledge, the first case of both drusen regression and subsequent CNV development within 7 months of successful macular hole surgery. A 73-year-old woman presented with a stage 3 full-thickness macular hole and large, confluent soft macular drusen in the right eye and a neovascular age-related macular degeneration (AMD) in the fellow eye. Four months after the successful macular hole surgery, significant regression of drusen was seen, especially in the temporal area to the fovea. Three months later, the patient developed CNV and her best-corrected visual acuity decreased to 20/100, despite further regression of macular drusen. Macular hole patients with macular soft drusen need to be carefully followed up after surgery for possible drusen regression and CNV development.
To evaluate the neuroprotective and neurite outgrowth effects of maltol, a natural aroma compound, on retinal ganglion cells (RGCs) under oxidative stress in vitro. Mouse primary RGCs were isolated using immunopanning–magnetic separation and exposed to H2O2 in the presence of maltol. The cell viability and apoptosis were determined by using adenosine 5′-triphosphate (ATP) assay and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL), respectively. Neurite outgrowth was assessed by immunofluorescence for α-tubulin. The activation of nuclear factor-κB (NF-κB) was also evaluated using immunofluorescence. When the RGCs were exposed to 20 μM of H2O2 for 16 h, their viability dropped to 40.3±3.4%. However, the maltol treatment restored the cells in a dose-dependent manner. The viability recovered to 73.9±5.1% with 10 μM of maltol and even reached 175.1±11.3% with 2 mM of maltol, as measured by ATP assay. This oxidative stress significantly increased the number of TUNEL-positive RGCs, but the maltol drastically reduced the proportion of those apoptotic cells. The oxidative stress hampered the neurite outgrowth of the RGCs, whereas maltol restored their ability to sprout neurites. Regarding NF-κB, the active form of phosphorylated NF-κB (pNF-κB) increased the oxidative stress level but the maltol treatment again reduced it to an unstressful level. Our data revealed that maltol attenuated the oxidative stress–induced injury in the primary mouse RGCs. Its neuroprotective and neurite outgrowth effects seemed to be related to NF-κB signaling. Maltol has potential as a new neuroprotective therapeutic agent for oxidative stress–related ocular diseases, including glaucoma.
14 June 2017 in Graefe's Archive for Clinical and Experimental Ophthalmology