Publications by authors named "Nádia C O Miguel"

6 Publications

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Morphologic and molecular study on the lens anterior capsule in systemic sclerosis.

Arq Bras Oftalmol 2021 Feb 3. Epub 2021 Feb 3.

Institute of Biomedical Sciences, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

This study aimed to analyze the anterior lens capsule specimens from both eyes of a patient with systemic sclerosis and compare them to the eyes of a control patient. No significant differences between systemic sclerosis and control eyes were observed in the results from the hematoxylin-eosin and picrosirius staining. In the samples obtained from both systemic sclerosis and control eyes, there were expressions of caspase, a molecule expressed in cell death by apoptosis. Heparanase was overexpressed in the systemic sclerosis sample compared to the control sample. Therefore, the anterior lens capsule of the patient with systemic sclerosis is probably affected by the disease since it showed marked expression of heparanase 1.
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http://dx.doi.org/10.5935/0004-2749.20210039DOI Listing
February 2021

Bevacizumab reduces neurocan content and gene expression in newborn rat retina in vitro.

Invest Ophthalmol Vis Sci 2014 Jul 24;55(8):5109-15. Epub 2014 Jul 24.

Laboratory of investigation in Ophthalmology (LIM-33), University of São Paulo Medical School, São Paulo, Brazil.

Purpose: Extracellular matrix (ECM) and cellular membrane proteoglycans (PGs) play important roles in neural differentiation and cell adhesion. Vascular endothelial growth factor, an important signal protein in vascular and retinal neural cell development, is retained in the ECM due to its high affinity for PG. Bevacizumab, an anti-VEGF agent, has been extensively used for treating retinal diseases in adult and newborn patients, although its effect on the developing retina remains largely unknown. The purpose of this study was to investigate the effect of bevacizumab on neurocan, phosphacan, and syndecan-3 PG levels in newborn rat retina.

Methods: Retinal explants of sixty 2-day-old Lister hooded rats were obtained after eye enucleation and maintained in culture media with or without bevacizumab for 48 hours. Immunohistochemical staining was assessed against neurocan, phosphacan, and syndecan-3. Proteoglycan content was quantified based on the intensity of immunohistochemical labeling. Gene expressions were quantified by real-time reverse-transcription polymerase chain reaction. The results from the treatment and control groups were compared.

Results: No significant difference in the staining intensity and mRNA expression of phosphacan and syndecan-3 was observed between the groups. However, a significant decrease in neurocan content and mRNA expression was observed in bevacizumab-treated retinal explants compared with controls.

Conclusions: Bevacizumab did not affect phosphacan and syndecan-3 levels but decreased neurocan content and gene expression. Therefore, it may interfere with early postnatal retinal cell differentiation. Although further studies are necessary to confirm our findings, we suggest anti-VEGF agents be used with caution in developing retinal tissue.
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http://dx.doi.org/10.1167/iovs.14-14466DOI Listing
July 2014

In vitro effects of bevacizumab treatment on newborn rat retinal cell proliferation, death, and differentiation.

Invest Ophthalmol Vis Sci 2012 Nov 29;53(12):7904-11. Epub 2012 Nov 29.

Programa de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

Purpose: Vascular endothelial growth factor (VEGF) is an important signal protein in vertebrate nervous development, promoting neurogenesis, neuronal patterning, and glial cell growth. Bevacizumab, an anti-VEGF agent, has been extensively used for controlling pathological retinal neovascularization in adult and newborn patients, although its effect on the developing retina remains largely unknown. The purpose of this study was to investigate the effect of bevacizumab on cell death, proliferation, and differentiation in newborn rat retina.

Methods: Retinal explants of sixty 2-day-old Lister hooded rats were obtained after eye enucleation and maintained in culture media with or without bevacizumab for 2 days. Immunohistochemical staining was assessed against proliferating cell nuclear antigen (PCNA, to detect cell proliferation); caspase-3 and beclin-1 (to investigate cell death); and vimentin and glial fibrillary acidic protein (GFAP, markers of glial cells). Gene expressions were quantified by real-time reverse-transcription polymerase chain reaction. Results from treatment and control groups were compared.

Results: No significant difference in the staining intensity (on immunohistochemistry) of PCNA, caspase-3, beclin-1, and GFAP, or in the levels of PCNA, caspase-3, beclin-1, and vimentin mRNA was observed between the groups. However, a significant increase in vimentin levels and a significant decrease in GFAP mRNA expression were observed in bevacizumab-treated retinal explants compared with controls.

Conclusions: Bevacizumab did not affect cell death or proliferation in early developing rat retina but appeared to interfere with glial cell maturation by increasing vimentin levels and downregulating GFAP gene expression. Thus, we suggest anti-VEGF agents be used with caution in developing retinal tissue.
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http://dx.doi.org/10.1167/iovs.12-10283DOI Listing
November 2012

Clinical and histopathological outcomes of subconjunctival triamcinolone injection for the treatment of acute ocular alkali burn in rabbits.

Cornea 2012 Feb;31(2):181-7

Department of Ophthalmology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

Purpose: To evaluate the efficacy and safety of subconjunctival injection of triamcinolone in the treatment of acute ocular alkali burn in rabbits.

Methods: Two groups of 5 rabbits were subjected to alkali burn (1 N NaOH). One group was treated with 1 subconjunctival injection of 0.3 mL of triamcinolone and the other with 1 subconjunctival injection of 0.3 mL of 0.9% saline. The affected corneas were observed for vascularization and opacity approximately 10 minutes after the burn and also after 7, 14, and 21 days. Photographs were taken for observation and statistical analyses. At all time intervals, the corneas were classified according to predetermined scores. Twenty-one days after the treatment, the animals were anesthetized, and their eyes were enucleated and processed for histopathology.

Results: Greater vascularization and opacity appeared in the animals that were treated with saline than in those treated with subconjunctival triamcinolone (vascularization: 7 days, P = 0.0107; 14 days, P = 0.0099; and 21 days, P = 0.0088; opacity: 7 days, P = 0.0079; 14 days, P = 0.0112; and 21 days, P = 0.0255). These results were also compatible with the morphological and statistical analyses, which revealed a more intense inflammatory process in the group treated with saline (P = 0.0317). No complications, such as corneal melting, perforation, or infection, were observed.

Conclusions: Subconjunctival injection of triamcinolone may be a therapeutic option for the treatment of acute ocular burn because it reduced the corneal inflammatory process, opacity, and vascularization, with no apparent clinical changes in the general state of the animal.
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http://dx.doi.org/10.1097/ICO.0b013e318221ce99DOI Listing
February 2012

Trypan blue staining for capsulorhexis: ultrastructural effect on lens epithelial cells and capsules.

J Cataract Refract Surg 2010 Apr;36(4):582-7

From the Division of Ophthalmology (Portes, Monteiro), Hospital das Clínicas, University of São Paulo Medical School, São Paulo, and the Biological Sciences Institute (Almeida, Allodi, Miguel), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

Purpose: To evaluate the ultrastructural effect of trypan blue 0.1% staining for capsulorhexis on lens epithelial cells (LECs) and capsules.

Setting: Division of Ophthalmology, University of São Paulo, São Paulo, Brazil.

Methods: Before capsulorhexis, patients were randomly assigned to 1 of 2 groups. Trypan blue 0.1% staining was performed in the treatment group. No trypan blue was used in the control group. Samples of capsules with LECs were fixed and analyzed with routine optical microscopy techniques, immunohistochemistry for beclin-1 expression (a marker of autophagy), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling to detect apoptosis, and transmission electron microscopy (TEM). Morphometric analyses were performed, and the 2 sets of data were compared.

Results: Each group comprised 15 patients. Cell death by autophagy and apoptosis was observed in the treatment group but not in the control group. The TEM images of subcapsular epithelium cells showed mitochondrial rupture, dilation of the cisterns of the endoplasmic reticulum, increased cytoplasmic and nuclear electron density, and abnormalities in the nuclear profile of trypan blue-stained cells. Morphometric analysis showed statistically significant differences between the 2 groups in the longest nuclear axes and the ratio between the total nuclear perimeter and the cell area (P = .03). The difference in capsule thickness between groups was not significant.

Conclusion: Trypan blue caused LEC death, which supports the hypothesis that staining with trypan blue 0.1% can help reduce the incidence of posterior capsule opacification after cataract surgery.

Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
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http://dx.doi.org/10.1016/j.jcrs.2009.11.005DOI Listing
April 2010