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Diabetic macular oedema (DMO) is the leading cause of vision loss in the working-age population. Blood-retinal barrier (BRB) dysfunction in diabetic retinopathy (DR), mainly at the level of the retinal vessels, has long been related with leakage and fluid accumulation, leading to macular oedema. However, the nourishment of the macula is provided by the choroid and a diabetic choroidopathy has been described. Therefore, there has been a growing interest in studying the role of the choroid in the pathophysiology of DR and DMO, mainly by optical coherence tomography (OCT). Nevertheless, there are conflicting results in the different studies. We summarize the results from the available studies, describe the limitations and confounding factors and discuss future procedures to avoid bias.

BackgroundIt has been claimed that the retina can be used as a window to study brain disorders. However, concerning Alzheimer’s disease (AD), it still remains controversial whether changes occurring in the brain and retina are associated. We aim to understand when changes start appearing in the retina and brain, how changes progress, and if they are correlated.MethodsWe carried out a unique longitudinal study, at 4, 8, 12, and 16 months of age, in a triple transgenic mouse model of AD (3×Tg-AD), which mimics pathological and neurobehavioral features of AD, as we have already shown. Retinal structure and physiology were evaluated in vivo using optical coherence tomography and electroretinography. Brain visual cortex structure was evaluated in vivo using magnetic resonance imaging.ResultsThe retinal thickness of 3×Tg-AD decreased, at all time points, except for the outer nuclear layer, where the opposite alteration was observed. Amplitudes in scotopic and photopic responses were increased throughout the study. Similarly, higher amplitude and lower phase values were observed in the photopic flicker response. No differences were found in the activity of retinal ganglion cells. Visual cortex gray matter volume was significantly reduced.ConclusionsOur results show that this animal model shows similar neural changes in the retina and brain visual cortex, i.e., retinal and brain thinning. Moreover, since similar changes occur in the retina and brain visual cortex, these observations support the possibility of using the eye as an additional tool (noninvasive) for early AD diagnosis and therapeutic monitoring.

The features of microparticles, as size, surface structure, and morphology, depend, mainly, on the methodology used for their preparation. Emulsion polymerization techniques are undoubtedly among the most widespread. However, the use of toxic, volatile organic solvents represents a major disadvantage, namely, because of environmental issues. In this study, we prepared glutaraldehyde crosslinked chitosan-poly(vinyl alcohol) microparticles by an improved water-in-oil emulsion technique using corn oil as organic phase. The application of this polymeric blend as microparticle is scarcely investigated. As resulting of the procedure here presented, spherical and smooth surface microparticles were obtained, with mean diameter of 16 lm. The cross-linking reaction between the aldehyde and the amino or the hydroxyl groups formed either an imine (Schiff's base) or an acetal bond, respectively, as analyzed by infrared spectroscopy. The microparticles here described did not present cytotoxic potential. Accordingly, this study can find promising and successful application in biotechnology.