Percorrer por autor "Silva, Rufino"
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- Choroidal and retinal structural, cellular and vascular changes in a rat model of Type 2 diabetesPublication . Campos, António; Martins, João; Campos, Elisa J.; Silva, Rufino; Ambrósio, António FranciscoIncreasing evidence points to inflammation as a key factor in the pathogenesis of diabetic retinopathy (DR). Choroidal changes in diabetes have been reported and several attempts were made to validate in vivo choroidal thickness (CT) as a marker of retinopathy. We aimed to study choroidal and retinal changes associated with retinopathy in an animal model of spontaneous Type 2 diabetes, Goto-Kakizaki (GK) rats. Sclerochoroidal whole mounts and cryosections were prepared from 52-week-old GK and age-matched control Wistar Han rats. CT was measured by optical coherence tomography. Microglia reactivity, pericyte and endothelial cells distribution, and immunoreactivity of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) were evaluated by immunofluorescence. Choroidal vessels were visualized by direct perfusion with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil). Choroidal vascular density was evaluated by fluorescence microscopy. GK rats had increased CT (58.40 ± 1.15 μm versus 50.90 ± 1.58 μm, p < 0.001), reduced vascular density of the choriocapillaris (CC) (p = 0.045), increased Iba1+ cells density in the outer retina (p = 0.003) and increased VEGFR2 immunoreactivity in most retinal layers (p = 0.021 to 0.037). Choroidal microglial cells and pericytes showed polarity in their distribution, sparing the innermost choroid. This cell-free gap in the inner choroid was more pronounced in GK rats. In summary, GK rats have increased CT with decreased vascular density in the innermost choroid, increased VEGFR2 immunoreactivity in the retina and increased Iba1+ cells density in the outer retina.
- Inflammatory Biomarkers in Diabetic Macular EdemaPublication . Campos, António; Furtado, Maria João; Carneiro, Ângela; Meireles, Angelina; Neves, Carlos; Ambrósio, António Francisco; Leal, Inês; Figueira João; Marques, João Pedro; Henriques, José; Falcão, Manuel; Gomes, Nuno; Flores, Rita; Silva, Rufino; Pessoa, BernardeteDiabetic retinopathy (DR) is a major complication of both Type 1 and Type 2 diabetes mellitus (T1DM and T2DM). Disease progression can result in visual impairment, primarily due to diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR). Although several ocular treatments are available for DME, a subset of patients fails to respond, reflecting the multifactorial, complex, and systemic nature of DR. Inflammatory biomarkers can be classified according to different characteristics, including imaging biomarkers—most commonly assessed using optical coherence tomography (OCT)—and molecular biomarkers, which are defined by their biochemical and biophysical properties. Pro- and anti-inflammatory cytokines, chemokines, adipokines, and inflammation-related enzymes are recognized as key inflammatory biomarkers and can be detected in the vitreous humour, aqueous humour, tears, serum, and other biological tissues. The identification and characterization of reliable biomarkers may help determine disease severity, monitor disease progression, and predict the risk of specific outcomes, thereby aiding in the prevention of end-stage disease (prognostic biomarkers). In addition, biomarkers may serve as predictive tools for therapeutic response, guiding personalized treatment strategies and enabling ongoing monitoring. This review provides a comprehensive overview of the role of inflammatory biomarkers in the diagnosis and management of DR and DME.
- Inflammatory cells proliferate in the choroid and retina without choroidal thickness change in early Type 1 diabetesPublication . Campos, António; Campos, Elisa J.; Martins, João; Rodrigues, Flávia S.C.; Silva, Rufino; Ambrósio, António FranciscoIncreasing evidence points to inflammation as a key factor in the pathogenesis of diabetic retinopathy (DR). Choroidal inflammatory changes in diabetes have been reported and in vivo choroidal thickness (CT) has been searched as a marker of retinopathy with contradictory results. We aimed to investigate the early stages in the retina and choroid in an animal model of Type 1 diabetes. Type 1 diabetes was induced in male Wistar rats via a single i.p. streptozotocin injection. At 8 weeks after disease onset, CT, choroidal vascular density, VEGF and VEGFR2 expression, microglial cell and pericyte distribution were evaluated. Diabetic rats showed no significant change in CT and choroidal vascular density. A widened pericyte-free gap between the retinal pigment epithelium and the choroid was observed in diabetic rats. The immunoreactivity of VEGFR2 was decreased in the retina of diabetic rats, despite no statistically significant difference in the immunoreactivity of VEGF. The density of microglial cells significantly increased in the choroid and retina of diabetic rats. Reactive microglial cells were found to be more abundant in the choroid of diabetic rats. Evidences of the interconnection between the superficial, intermediate, and deep plexuses of the retina were also observed. At early stages, Type 1 diabetes does not affect choroidal thickness and choroidal vascular density. Proliferation and reactivity of microglial cells occurs in the choroidal stroma and the retina. The expression of VEGFR2 decreases in the retina.
- The value of choroidal thickness in diabetic macular oedema is contradictoryPublication . Campos, António; Campos, Elisa J.; Martins, João; Ambrósio, António Francisco; Silva, Rufino
- The value of choroidal thickness in diabetic macular oedema is contradictoryPublication . Campos, António; Campos, Elisa J.; Martins, João; Ambrósio, António Francisco; Silva, Rufino