Abstract: Subretinal inflammation plays a critical role in retinal degenerative diseases. Although activated macrophages have been shown to play a key role in the progression of retinopathies and specifically in age-related macular degeneration, little is known about the mechanisms involved in the loss of photoreceptors leading to vision impairment. In our study on retinal damages induced by photo-oxidative stress, we have observed that CD36-deficient mice featured less subretinal macrophage accumulation with attenuated photoreceptor degeneration compared to wild-type (WT) mice. Treatment with CD36-selective azapeptide ligand (labelled MPE-001) as modulator of the inflammatory environment of the retina reduced subretinal macrophage/activated microglia accumulation with preservation of photoreceptor layers and function assessed by ERG in WT, in a CD36-dependent manner. The azapeptide modulated the transcriptome of subretinal macrophage/activated microglia by reducing pro-inflammatory markers. In isolated macrophages, the CD36-selective azapeptide induced dissociation of the CD36-TLR2/6 heterodimer complex (using FRET) altering the TLR2 signaling pathway, thus decreasing NF-KB activation and inflammasome activity. The azapeptide also incurred cytoprotection against photoreceptor apoptosis elicited by activated macrophages. These findings suggest that the azapeptide as ligand of co-receptor CD36 decreases the inflammatory response by modulating CD36-TLR2/6 complex signaling pathway in macrophages, and suggests its potential application in the treatment of retinal degenerative diseases.

Abstract: Statins are used widely to treat hypercholesterolemia and atherosclerotic cardiovascular disease. They have inflammatory and immunomodulatory effects potentially useful for managing systemic autoimmune diseases such as rheumatoid arthritis, lupus erythematosus and multiple sclerosis. Statins also have anti-oxidative and large-vessel endothelial supportive properties that occur independent of their lipid-lowering effects. Additionally, statins can suppress macrophage and microglial activation responsible for initiating inflammatory cytokine release. More than forty percent of adults aged 65 years or older use statins in the United States and Australia, a prevalence that increases with age. The effects of statin usage on ophthalmic practice are probably underrecognized. Cardiovascular disease and age-related macular degeneration (AMD) share common risk factors, consistent with the “vascular model” of AMD pathogenesis that implicates impaired choroidal circulation in Bruch’s membrane lipoprotein accumulation. AMD has a complex multifactorial pathogenesis involving oxidative stress, choroidal vascular dysfunction, dysregulated complement-cascade-mediated inflammation and pro-inflammatory and pro-angiogenic growth factors. Many of these components are hypothetically amenable to the primary (cholesterol lowering) and secondary (anti-inflammatory, anti-oxidative, anti-vasculopathy) effects of statin use. Experimental studies have been promising, epidemiological trails have produced conflicting results and three prospective clinical trials have been inconclusive at demonstrating the value of statin therapy for delaying or preventing AMD. Cumulative evidence to date has failed to prove conclusively that statins are beneficial for preventing or treating AMD.

Abstract: The rare disease of chronic infantile neurological cutaneous and articular (CINCA) syndrome, is caused by the over-secretion of interleukin (IL)-1β due to a gain-of-function NLRP3 gene mutation in the autosomal chromosome which often involves in eyes. In this report, we studied a 9-year-old girl with CINCA. The eyes were also involved and presented bilateral papilledema. Genetic testing revealed that the symptoms were caused by a novel gene mutation site (c.913G>A, p. D305N) in conservative domain exon-3 of NLRP3 which is gain-function gene of CINCA. The patient had the characteristic facial features, frontal fossa and saddle nose, manifested the generalized urticaria-like skin rash at two weeks after birth, periodic fever 6 months after birth, sensorineural deafness at 7 years old, and bilateral papilledema, aseptic meningitis and knee arthropathy at 9 years old. White cell counts, C-reactive protein increased and intracranial pressure raised to 300 mmH2O. The meningeal thickening enhanced by gadolinium in magnetic resonance imaging (MRI). Based on clinical features and genetic test, the girl was diagnosed bilateral papilledema secondary to CINCA and administered prednisone and lowered intracranial pressure medicine to resolve symptoms. With 3-year follow-up, patient had no inflammatory flare-up with visual acuity improvement. The finding of novel genetic mutation site (p. D305N) in NLRP3 gene expanded genotype spectrum associated with CINCA. This case also expanded the cause spectrum of papilledema and it highlighted systemic disease history for patients with bilateral papilledema.