Thinning Of Outer Retinal Layers Research Articles

Cancer-associated retinopathy as an initial presentation of gynecologic small-cell carcinoma

Abstract: A 56-year-old female presented with bilateral progressive blurred vision over 1 month. She has no known malignancy before her initial visit to our ophthalmologic clinic. Her best-corrected visual acuity decreased to hand motion from 30 cm in both eyes. Optical coherence tomography exhibited parafoveal thinning of outer retinal layers bilaterally. Fluorescein angiography and indocyanine green angiography disclosed hypofluorescent spots in late phase in both eyes. The suspicion of cancer-associated retinopathy (CAR) prompted us to investigate and refer for further systemic disease including occult malignancy. The patient was diagnosed with small-cell carcinoma of the endometrium or cervix, which is an extremely rare and aggressive neuroendocrine tumor. The patient was treated with oral prednisone with improved visual acuity. The patient expired from sepsis 2 months after her initial visit to our ophthalmologic clinic. In selected cases, CAR may present before the diagnosis of primary cancer. It is essential to recognize its ophthalmic manifestation for early discovery of primary malignancy.

Retinal neurodegenerative changes in the adult insulin receptor substrate-2 deficient mouse

Insulin receptor substrate-2 (Irs2) mediates peripheral insulin action and is essential for retinal health. Previous investigations have reported severe photoreceptor degeneration and abnormal visual function in Irs2-deficient mice. However, molecular changes in the Irs2−/− mouse retina have not been described. In this study, we examined retinal degenerative changes in neuronal and glial cells of adult (9- and 12-week old) Irs2−/− mice by immunohistochemistry. 9-week old Irs2−/− mice showed significant thinning of outer retinal layers, concomitant to Müller and microglial cell activation. Photoreceptor cells displayed different signs of degeneration, such as outer/inner segment atrophy, redistribution of rod- and cone-opsins and spatial disorganization of cone cells. This was accompanied by synaptic changes at the outer plexiform layer, including the retraction of rod-spherules, reduction of photoreceptor synaptic ribbons and synaptic remodeling in second order neurons (i.e. loss and sprouting of dendritic processes in rod bipolar and horizontal cells). By 12 weeks of age, the thickness of inner retinal layers was severely affected. Although inner plexiform layer stratification remained unchanged at this stage, rod bipolar cell axon terminals were significantly depleted. Significant loss of Brn3a+ retinal ganglion cells occurred in 12-week old Irs2−/− mice, in contrast to younger ages. Adult Irs2−/− mice showed clear hallmarks of neurodegeneration and disruption of the inner retina with increasing age. Pharmacological stimulation of Irs2 signaling pathway may provide additional neuroprotection in certain degenerative retinopathies.