Sul Gee Lee

Effect of lipoic acid on expression of angiogenic factors in diabetic rat retina.

Background:  This study evaluated the effect of a lipoic acid on reactive oxygen species formation and the simultaneous changes of several angiogenic factors in an experimental diabetic rat retina.

Simvastatin suppresses expression of angiogenic factors in the retinas of rats with streptozotocin-induced diabetes

BackgroundAngiogenic factors such as vascular endothelial growth factor (VEGF), erythropoietin, and angiopoietin play important roles in the pathophysiology of diabetic retinopathy. Increased amounts of reactive oxygen species (ROS) are also known to associated with diabetic retinopathy and VEGF expression. This study evaluated the effect of a simvastatin on ROS generation and the changes in various angiogenic factors in the retinas of diabetic rats.MethodsThe rats were divided into normal, diabetes mellitus (DM), and simvastatin-treated groups (each group, n = 10). Diabetes was induced by intraperitoneal injection of streptozotocin into 20 Sprague–Dawley rats. After diabetic induction, simvastatin (5mg/kg) was administered orally to ten rats. The expression levels of VEGF, erythropoietin, angiopoietin 1 and 2, and NADPH oxidase were examined in rat retinas by RT-PCR and Western blot. Superoxide formation was examined by dihydroethidium (DHE) staining.ResultsDHE analysis revealed increased superoxide formation in the retinas of the diabetic group, which was decreased in the group treated with simvastatin. Western blot analysis showed that NADPH oxidase levels were decreased in the diabetic group and remained normal in the simvastatin-treated group. Simvastatin treatment blocked hyperglycemia-induced increases in VEGF, angiopoietin 2 and erythropoietin levels, as demonstrated by RT-PCR and Western blot analysis.ConclusionsSimvastatin treatment led to suppression of superoxide formation and decreased expression of VEGF, angiopoietin 2 and erythropoietin in diabetic rat retinas.

Expression of Stat3 and indoleamine 2, 3-dioxygenase in cornea keratocytes as factor of ocular immune privilege

PurposeOcular immune privilege is a multifactorial phenomenon evolutionally selected to prevent immunogenic inflammation from disrupting the visual axis and causing blindness. Here, we investigated the role of signal transducers and activators of transcription (Stat3) and indoleamine 2,3-dioxygenase (IDO) in ocular immune privilege in corneal stromal cells.MethodsHuman keratocytes were isolated and cultured in vitro, and Stat3 and IDO expression on keratocytes was investigated by reverse transcription polymerase chain reaction (RT-PCR). The active form of Stat3 was detected by flow-cytometry, and IDO enzyme activity following IFN-γ stimulation of keratocytes was measured by tryptophan to kynurenine conversion with photometric determination of kynurenine concentration in the supernatant.ResultsStat3 was constitutively expressed in cultured keratocytes and up-regulated following IFN-γ stimulation. The active form of Stat3 was also up-regulated following IFN-γ stimulation. IDO expression and enzyme activity was markedly induced following IFN-γ stimulation, but this induction was prevented by the IDO specific inhibitor, 1-methyl tryptophan (1-MT).ConclusionsOn the basis of this study, Stat3 and IDO may act as a factor of ocular immune privilege in corneal keratocytes. Thus, focus on these inhibitory molecules should be considered in studies aimed at developing therapeutic agents for controlling ocular inflammatory or immune diseases.

Antibacterial Properties Of Artificial Eyes Containing Nano-sized Particle Silver

Background: The long-term use of an artificial eyes can lead to complications. Persistent physical stimulation and foreign body contact cause secondary infections. Secondary infection is an important complication after the placement of a artificial eyes and may be difficult to control without removing the artificial eyes. Because of these complications, patients get difficulties to wear prosthesis. Furthermore artificial eyes can change the normal bacterial flora of the patient’s conjunctiva. Such postoperative infections might be overcome by improving the antimicrobial properties of the prosthesis surface. Methods: The space in the mold previously occupied by wax was filled with polymethyl methacrylate (PMMA) resin containing silver at a concentration of 300–700 ppm (parts per million) and the prosthesis was then heat cured. Microorganisms were grown on the treated and control surfaces. We cultured for 24 hours, then counted the number of bacteria in resin compositions containing nano-sized silver particles and controls (Stomacher 400® POLY-BAG). Results: The surface of the artificial eye containing silver grew significantly fewer Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli on in vitro bacterial cultures. The antimicrobial activity was 4.8–6.2 times stronger than for the controls. The numbers of bacteria decreased by 99.9% using the PMMA resin containing silver. Conclusion: The artificial eyes containing silver that were produced in this study have antibacterial activity, cause little eye discharge, and emit far-infrared rays and anions, all of which promote the ocular health of the person wearing the artificial eye.

Ophthalmologic findings of Boucher-Neuhäuser syndrome.

To report a case of Boucher-Neuhäuser syndrome, which is an autosomal recessive disorder characterized by the triad of spinocerebellar ataxia, chorioretinal dystrophy, and hypogonadotropic hypogonadism. An 18-year-old man was seen for visual problems, which had been diagnosed as retinitis pigmentosa at the age of 12 years. His puberty was delayed. At 16 years of age, the patient experienced progressive deterioration of his balance and gait disturbance. Then he was referred to our clinic because Boucher-Neuhäuser syndrome was suspected. He had no specific family history; his visual acuity was 0.04 in both eyes. We observed broad retinal pigment epithelium atrophy and degeneration in both fundi. Both fluorescein and indocyanine green angiography showed choriocapillaris atrophy in the posterior pole area and midperiphery. Macular optical coherence tomography showed thinning of the neurosensory retina. An electroretinographic examination showed no photopic or scotopic responses. The Boucher-Neuhäuser syndrome should be included in the differential diagnosis of patients with retinitis pigment epithelium atrophy and degeneration.