Jorge Mancini

Retinal upregulation of inflammatory and proangiogenic markers in a model of neonatal diabetic rats fed on a high-fat-diet

BackgroundThe contemporary peak of diabetes seems to be related to obesity, sedentary lifestyle and diet. Diabetic retinopathy is the most leading cause of blindness in adulthood in industrialized countries. Our purpose was to evaluate the effect of a high-fat-diet (HFD) on the retina of diabetic rats.MethodsTwo groups of Wistar rats were injected with streptozotocin (STZ) two days after birth using 45 and 90 mg/kg, respectively. At 8 weeks the group on lower doses started to be fed on a HFD. Animals were sacrificed at 37 weeks of diabetes. A control group was made up of non-diabetic rats. Retinal flat mounts were examined using the trypsin digestion technique. Pericytes counts were compared between diabetic and control rats. Cross retinal sections were analyzed by histological techniques and immunohistochemistry and immunofluorescent technique. Primary antibodies against inflammatory and proangiogenic mediators such as RAGE, GFAP, 5-LO, VEGF and TNF-α were used for immunohistochemistry and Western Blot (WB) analyses.ResultsIn the two diabetic groups we observed GFAP-positive cells with a morphology and spatial organization similar to those seen in Müller cells. Both diabetic groups had a significantly lower number of pericytes than non-diabetic animals.Increased retinal immunoreactivity of GFAP, RAGE, TNF-α, VEGF and 5-LO was seen in diabetic animals fed on HFD compared to the other groups of animals. WB analysis revealed a higher expression of 5-LO, VEGF, TNF-α and RAGE in the retina of diabetic rats on HFD than in controls and diabetics fed on a normal diet. The percentage of RAGE-stained ganglion cells and ganglion cells was found to be significantly lower in animals on a HFD than in the other animals.ConclusionsDiabetic animals fed on a HFD showed an increased upregulation of inflammatory and proangiogenic markers. This animal model may be useful to study mechanisms of diabetic retinopathy and therapeutic targets.

Involvement of purinergic P2 receptors in experimental retinal neovascularization.

Purpose: The present study was aimed to investigate the expression of purinergic P2 receptors in oxygen-induced retinal neovascularization. Methods: Immunohistochemistry was used to study the expression of purinergic P2Y2 and P2X2 receptors in the neonatal mouse retina during normal vascular development and after oxygen-induced retinopathy (OIR). The effect of the P2 antagonists, suramin and PPADS, on the extent of oxygen-induced retinal neovascularization was analyzed. Results: In normal mice, the expression of P2Y2 receptors was weak throughout the retina, whereas P2X2 receptor expression was detected in the outer plexiform layer. In mice treated with oxygen, P2Y2 expression was detected in the ganglion and in the nerve fiber layers, whereas P2X2 expression was found in the inner and outer plexiform layers. Oxygen-induced preretinal neovascularization was strongly inhibited by the P2 antagonists, suramin (p < 0.05) and PPADS (p < 0.05), and this was accompanied by a down-regulation of P2X2 receptor expression in the inner plexiform layer in suramin-treated mice. Conclusions: The data suggest that purinergic P2 receptors are involved in neovascularization associated with OIR.

FUSARIUM SOLANI SUBRETINAL ABSCESS IN A PATIENT WITH ACUTE MYELOID LEUKEMIA.

Purpose: To report on a case of Fusarium solani subretinal abscess in a patient with acute myeloid leukemia treated with an allogenic bone marrow transplant. Methods: A 47-year-old male with a history of acute myeloid leukemia with intermediate cytogenetic risk was admitted in our hospital. The disease relapsed after two cycles of chemotherapy. He was then treated with an allogenic bone marrow transplant, with busulfan, cyclophosphamide, and thymoglobulin. One week after the procedure, a sepsis of unknown origin in neutropenia occurred. Blood cultures and sputum were negative for bacteria and fungi. At the eighth week after the procedure, the patient had acute vision loss of the right eye. Funduscopy in the right eye revealed an inferior temporal yellowish white elevated lesion of approximately 10 disk areas and superficial perifoveal and perilesional hemorrhages. Results: Vitrectomy was performed and samples from the vitreous and the subretinal abscess material were sent for analysis. Vitreous and subretinal specimens grew colonies of a fungus morphologically consistent with F. solani. Conclusion: Fusarium solani should be included in the differential diagnosis of subretinal abscesses.