Amyloid-beta deposits accumulate with age in the retina of a transgenic mouse model of AD. The amyloid-beta loads are accompanied by increased immunoreactivity for MCP-1, F4/80, and TUNEL-positive profiles in the RGC layer. The results suggest that amyloid-beta causes neurodegeneration in the retina of the doubly mutant transgenic mouse model of AD.

Age-related macular degeneration (AMD) is the leading cause of legal blindness in the elderly in industrialized countries. AMD is a multifactorial disease influenced by both genetic and environmental risk factors. Progression of AMD is characterized by an increase in the number and size of drusen, extracellular deposits, which accumulate between the retinal pigment epithelium (RPE) and Bruch's membrane (BM) in outer retina. The major pathways associated with its pathogenesis include oxidative stress and inflammation in the early stages of AMD. Little is known about the interactions among these mechanisms that drive the transition from early to late stages of AMD, such as geographic atrophy (GA) or choroidal neovascularization (CNV). As part of the innate immune system, inflammasome activation has been identified in RPE cells and proposed to be a causal factor for RPE dysfunction and degeneration. Here, we will first review the classic model of inflammasome activation, then discuss the potentials of AMD-related factors to activate the inflammasome in both nonocular immune cells and RPE cells, and finally introduce several novel mechanisms for regulating the inflammasome activity.

Chronic inflammation is a key pathogenic process in age-related macular degeneration (AMD). Amyloid-beta (Aβ) is a constituent of AMD drusen and promotes the activation of NLRP3 inflammasome which facilitates the production of cytokines. We investigated the role of transcription factor NF-κB in the activation of inflammasome in the RPE and the effect of vinpocetine, a dietary supplement with inhibitory effect on NF-κB. ARPE19/NF-κB-luciferase reporter cells treated with Aβ demonstrated enhanced NF-κB activation that was significantly suppressed by vinpocetine. Intraperitoneal injection of vinpocetine (15 mg/kg) inhibited NF-κB nuclear translocation and reduced the expression and activation of NLRP3, caspase-1, IL-1β, IL-18, and TNF-α in the RPE of adult rats that received intraocular Aβ, as measured by retinal immunohistochemistry and Western blot. Cytokine level in the vitreous was assayed using multiplex suspension arrays and revealed significantly lower concentration of MIP-3α, IL-6, IL-1α, IL-1β, IL-18, and TNF-α in vinpocetine treated animals. These results suggest that the NF-κB pathway is activated by Aβ in the RPE and signals the priming of NLRP3 inflammasome and the expression of pro-inflammatory cytokines including the inflammasome substrates IL-1β and IL-18. NF-κB inhibition may be an effective approach to stem the chronic inflammatory milieu that underlies the development of AMD. Vinpocetine is a potentially useful anti-inflammatory agent that is well-tolerated in long term use.

Lamellar macular hole with LHEP may demonstrate closure after pars plana vitrectomy with LHEP and internal limiting membrane peeling and gas tamponade. There was considerable improvement in visual acuity. It is possible that LHEP originates from middle retinal layers of the lamellar hole defect because it contains retinal glial cells, specifically Müller cells.

Alzheimer’s disease (AD) is the most prevalent form of dementia, accounting for 60–70% of all dementias. AD is often under-diagnosed and recognized only at a later, more advanced stage, and this delay in diagnosis has been suggested as a contributing factor in the numerous unsuccessful AD treatment trials. Although there is no known cure for AD, early diagnosis is important for disease management and care. A hallmark of AD is the deposition of amyloid-β (Aβ)-containing senile neuritic plaques and neurofibrillary tangles composed of hyperphosporylated tau in the brain. However, current in vivo methods to quantify Aβ in the brain are invasive, requiring radioactive tracers and positron emission tomography. Toward development of alternative methods to assess AD progression, we focus on the retinal manifestation of AD pathology. The retina is an extension of the central nervous system uniquely accessible to light-based, non-invasive ophthalmic imaging. However, earlier studies in human retina indicate that the literature is divided on the presence of Aβ in the AD retina. To help resolve this disparity, this study assessed retinal tissues from neuropathologically confirmed AD cases to determine the regional distribution of Aβ in retinal wholemounts and to inform on future retinal image studies targeting Aβ. Concurrent post-mortem brain tissues were also collected. Neuropathological cortical assessments including neuritic plaque (NP) scores and cerebral amyloid angiopathy (CAA) were correlated with retinal Aβ using immunohistochemistry, confocal microscopy, and quantitative image analysis. Aβ load was compared between AD and control (non-AD) eyes. Our results indicate that levels of intracellular and extracellular Aβ retinal deposits were significantly higher in AD than controls. Mid-peripheral Aβ levels were greater than central retina in both AD and control eyes. In AD retina, higher intracellular Aβ was associated with lower NP score, while higher extracellular Aβ was associated with higher CAA score. Our data support the feasibility of using the retinal tissue to assess ocular Aβ as a surrogate measure of Aβ in the brain of individuals with AD. Specifically, mid-peripheral retina possesses more Aβ deposition than central retina, and thus may be the optimal location for future in vivo ocular imaging.