Erdem Dinç

Bioactive self-assembled peptide nanofibers for corneal stroma regeneration.

Defects in the corneal stroma caused by trauma or diseases such as macular corneal dystrophy and keratoconus can be detrimental for vision. Development of therapeutic methods to enhance corneal regeneration is essential for treatment of these defects. This paper describes a bioactive peptide nanofiber scaffold system for corneal tissue regeneration. These nanofibers are formed by self-assembling peptide amphiphile molecules containing laminin and fibronectin inspired sequences. Human corneal keratocyte cells cultured on laminin-mimetic peptide nanofibers retained their characteristic morphology, and their proliferation was enhanced compared with cells cultured on fibronectin-mimetic nanofibers. When these nanofibers were used for damaged rabbit corneas, laminin-mimetic peptide nanofibers increased keratocyte migration and supported stroma regeneration. These results suggest that laminin-mimetic peptide nanofibers provide a promising injectable, synthetic scaffold system for cornea stroma regeneration.

Parry-Romberg syndrome associated with anterior uveitis and retinal vasculitis

ous debris that was positive for silicone on energy dispersive xray analysis (Figs. 2 and3), indicating that the material in the vacuoles was silicone, not perfluorocarbon liquid. Others have reported histopathologic evidence of granulomatous inflammation due to the presence of silicone oil in 1 eye. Histopathological examination of an eye enucleated for chronic retinal detachment treated 20 years earlier with silicone oil showed vacuoles that were termed ‘‘silicone granulomas’’ in preretinal membranes, the subretinal space, and the choroid.Other clinical/histopathologic studies have confirmed the association of granulomatous inflammation following retinal detachment surgery with intraocular silicone oil injection. The potential antigenicity of silicone has been implicated in a wide variety of circumstances in which silicone implants, including silicone bands and sponges, have been inserted. Silicone oil has been shown to be a mediator in a number of destructive immunologic reactions in human beings and in animal models. In animal studies, silicone is a well known and powerful adjuvant in the production of antibodies to a wide variety of antigens, including rat thyroglobulin, bovine collagen II, and bovine serum albumin in mice. In mice, intraperitoneal injection of silicone oil causes persistent elevation of serum immunoglobulinM and activates macrophages and interleukin-1 beta. Our case is unique in that granulomatous uveitis developed in the previously normal fellow eye in which siliconeoil hadnotbeen inserted,which suggests that siliconeoil may incite a granulomatous inflammatory response that may affect both eyes, including the eye that does not contain any silicone oil. The demonstration by energy dispersive x-ray analysis of silicone oil in the phagocytosedmaterial inmacrophages and foreign body giant cells in the diseased eye is strong evidence that silicone may be the inciting agent.

Effects of intravitreal bevacizumab in repeated doses: an experimental study.

Purpose: To evaluate the effects of repeated 1.25-mg intravitreal bevacizumab injections on cornea and uveoretinal tissues using histologic and biochemical analyses. Methods: Twenty-four New Zealand albino rabbits were used. Twelve rabbits received an injection of bevacizumab in their right eyes three times with an interval of 25 days (Group 1); their contralateral eyes served as controls (Group 2). Six rabbits had an injection of vehicle in both eyes (Group 3), with the same regimen as bevacizumab, and six rabbits’ eyes were used as a sham group (Group 4). Enucleated eyes were used for histologic and biochemical analyses, which included the activities of caspase 3 and 8 enzymes, glutathione content, catalase activity, and malondialdehyde content. Results: No inflammation in aqueous humor and no sign of corneal or uveoretinal toxicity was found in bevacizumab-injected eyes. The difference of activity of corneal caspase 8 enzyme between Groups 1 and 2 and between Groups 1 and 4 was statistically significant (P < 0.05). In the uveoretinal tissue, in Group 1, the activities of caspase 3 and 8 enzymes were the lowest, and uveoretinal malondialdehyde content was also significantly lower than Group 4. Conclusion: A repeated dose of intravitreal bevacizumab injection did not cause a toxic effect on cornea and uveoretinal tissue. Biochemically, it also did not cause any apoptosis, oxidative reaction, or lipid peroxidation. Instead, bevacizumab injection caused a considerable decrease in the apoptotic enzyme activities and lipid peroxidation in the uveoretinal tissue. Further studies are needed to be conducted for possible detrimental side effects and apoptotic and oxidative effects of repeated bevacizumab injections on both the injected and the contralateral eyes.

Intravitreal bevacizumab effects on VEGF levels in distant organs: an experimental study

Abstract Purpose: The aim of this study was to determine the effects of single-dose intravitreal bevacizumab on the levels of vascular endothelial growth factor (VEGF) in serum and distant organs. Methods: Adult New Zealand albino rabbits (n = 40) were divided into experimental and control groups. Experimental rabbits received a single 0.05 ml intravitreal injection of 1.25 mg bevacizumab (Avastin) into the right eye, and control rabbits (n = 8) received no injection. Following injection, group 1 rabbits (n = 8) were sacrificed on day 1, group 2 rabbits (n = 8) on day 7, group 3 rabbits (n = 8) on day 14, and group 4 rabbits (n = 8) on day 28; control rabbits were sacrificed on day 28. After sacrifice, samples of brain, heart, liver, kidney and blood were collected. Levels of VEGF in serum and tissue were measured using enzyme-linked immunosorbent assay. The presence of bevacizumab was evaluated by immunofluorescence staining in tissues. Results: Positive bevacizumab immunoreactivity was observed in brain, heart and kidney. Serum VEGF levels significantly decreased in groups 3 and 4 compared with controls (p < 0.05). Liver VEGF levels significantly decreased in group 3 compared with controls (p < 0.05). Conclusions: Intravitreal bevacizumab not only may escape from the blood-retinal barrier and enter the general circulation, but also may be disseminated to distant organs. Our study demonstrates that a single dose of intravitreally injected bevacizumab decreases VEGF levels in serum and liver.

Evaluation of microRNA responses in ARPE-19 cells against the oxidative stress

Abstract Purpose: This study aimed to determine microRNA (miRNA) expression profile of human retinal pigment epithelium cell (ARPE-19) against the oxidative stress induced by hydrogen peroxide (H2O2). Methods: ARPE-19 cells were incubated with different concentrations of H2O2 (200, 600 and 800 μM) for 18 h, and then cell viability, vascular endothelial growth factor levels and total oxidant status were evaluated. Expressions of 1152 miRNA were determined by quantitative real-time PCR in each group. Results: Expressions of 90 miRNA were significantly changed in the ARPE-19 cells incubated with H2O2 compared to control group. However, miR-143-3p was only found to be expressed in groups incubated with H2O2. While 24 miRNA (hsa-miR-200c-3p, miR-192-5p, miR-194-5p, miR-141-3p, miR-658, miR-18 b-5p, miR-486-5p, miR-525-3p, miR-493-3p, miR-518d-3p, miR-29 b-1-5p, miR-675-3p, miR-1238-3p, miR-195-3p, miR-1539, miR-490-5p, miR-3200-5p, miR-1273d, miR-130a-5p, miR-30 b-5p, miR-1247-5p, miR-1910-5p, miR27a-5p and miR-200 b-3p) upregulated due to the increased dose of H2O2, nine miRNA (hsa-miR-96-5p, miR-33a-5p, miR-345-5p, miR-106 b-3p, miR-1285-3p, miR-23 b-5p, miR-27 b-5p, miR-103a-3p and miR-4289) were also found to be downregulated. Conclusion: This study suggests that oxidative stress may be an important factor on expression of miRNAs in ARPE-19 cells. These miRNAs may have a role in the pathogenesis of age-related macular degeneration related to oxidative stress. However, this relationship needs to be examined in new studies by evaluation of pathways and target genes.

Protective Effect of Combined Caffeic Acid Phenethyl Ester and Bevacizumab Against Hydrogen Peroxide-Induced Oxidative Stress in Human RPE Cells

ABSTRACT Purpose: This study aimed to evaluate the protective effects of caffeic acid phenethyl ester (CAPE) and combined CAPE-bevacizumab against oxidative stress induced by hydrogen peroxide (H2O2) in human retinal pigment epithelium. Methods: ARPE-19 cells were pretreated with 5, 10, and 30 μM CAPE alone and in combination with bevacizumab for 3 h, then exposed to H2O2 for 16 h. Cell viability was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Vascular endothelial growth factor (VEGF) protein levels in the medium were measured using a human VEGF ELISA kit. Total antioxidant status (TAS) and total oxidant status (TOS) were measured in ARPE-19 cells using the test kit from Rel Assay. Expression levels of VEGF, Bax, Bcl-2, cytochrome c, apoptotic protease activating factor-1 (apaf-1), and caspase-3 were determined using reverse transcription polymerase chain reaction. Results: Pretreatment of ARPE-19 cells with 30 μM CAPE and combined CAPE-bevacizumab reduced H2O2 mediated cell death. H2O2-induced oxidative stress increased TOS and VEGF production, which was significantly inhibited by CAPE and the CAPE-bevacizumab combination. VEGF, Bax, cytochrome c, apaf-1, and caspase-3 gene expressions were significantly decreased in cells pretreated with 5, 10, and 30 μM CAPE and combined CAPE-bevacizumab compared to the H2O2 group. In addition, Bcl-2 expression was significantly increased in both the CAPE and CAPE-bevacizumab combination groups compared to the H2O2 group. Conclusions: CAPE has a protective effect on ARPE-19 cells against oxidative stress, and VEGF protein level and expression can be decreased by incubation with different concentrations of CAPE. These results demonstrate that CAPE suppresses the mitochondria-mediated apoptosis in ARPE-19 cells under oxidative stress. In addition, the use of CAPE in combination with bevacizumab has an additive effect.

Common Blepharitis Related to Phthiriasis Palpebrarum: Argon Laser Phototherapy

A 42-year-old woman was admitted to Mersin University, Department of Ophthalmology Clinic with itching and burning sensation of the right eye for 3 weeks. In her slit-lamp examination, nits and lice, attached to the upper and lower eyelashes of her right eye, were observed. Lice and nits were destroyed by argon laser phototherapy and were removed with the help of a fine forceps thereafter. Argon laser phototherapy is a quick, effective, and safe treatment modality for phthiriasis palpebrarum.

Central retinal artery occlusion and irreversible blindness due to paranasal sinus infection in a pregnant woman.

Paranasal sinus infections can cause severe orbital complications leading to blindness. The mechanism for blindness with paranasal sinus infection can involve thrombophlebitis ischemia by valveless orbital veins, pressure ischemia resulting in central artery occlusion, or optic neuritis as a reaction to adherent infection. We present a case of orbital cellulitis leading to central retinal artery occlusion and blindness in a 30-week pregnant woman.

Efficacy of mitomycin-C and infliximab in reducing adhesionand fibrosis following strabismus surgery*

BACKGROUND/AIM The present study aimed to investigate the efficacy of mitomycin-C (MMC) and infliximab (INF) in reducing adhesion and fibrosis following strabismus surgery. MATERIALS AND METHODS Forty eyes of 20 albino rabbits were separated into MMC and INF groups. Right and left eyes of rabbits were assigned to the drug and control groups, respectively. The superior rectus muscle was disinserted, the drug was administered to the surgical area for 5 min in the drug eyes (MMC 0.2 mg/mL or INF 5 mg/mL), and physiological saline was administered to the control eyes. Surgical areas were rinsed with 10 mL of physiological saline. The disinserted muscle was then sutured to the same area using 6.0 Vicryl. The rabbits were sacrificed after 4 weeks for histopathological examination. RESULTS Significant reduction was observed in fibrosis in the INF group as compared to the control group (P = 0.005). Although adhesion formation in the drug eyes reduced in the MMC and INF groups as compared to the control group, the difference was not significant (P = 0.280 and P = 0.579, respectively). CONCLUSION This study demonstrated the fibrosis-preventing efficacy of IFN; thus, it can be a good option in reducing fibrosis in strabismus surgery.

Effects of intravitreal injection of bevacizumab on nitric oxide levels

PurposeThis study aimed to determine the possible effects of single-dose intravitreal bevacizumab on nitric oxide (NO) levels in serum and remote organs and to reveal one of the possible mechanisms in the pathophysiology of hypertension.MethodsThirty-eight adult New Zealand albino rabbits were divided into a control group (no injection was performed, killed on day 28 of the study), group 1 (killed on day 1 of the study), group 2 (killed on day 7 of the study), group 3 (killed on day 14 of the study), and group 4 (killed on day 28 of the study). The right eyes of the animals in groups 1–4 received an intravitreal single injection of 1.25 mg (0.05 ml) bevacizumab (Avastin), and their brain, heart, liver, kidney, and blood samples were collected. NO levels were evaluated in the serum and organ homogenates. Kidney tissues were assessed by electron microscopy.ResultsSerum, brain, kidney, and liver NO levels significantly decreased in groups 2, 3, and 4 as compared with the control group (P<0.05). In addition, heart NO levels significantly decreased in groups 3 and 4 compared with the control group (P<0.05). There were no electron microscopic changes in the kidneys of either group.ConclusionsThis study demonstrated that single intravitreal injection of bevacizumab decreased NO levels in serum, brain, heart, liver, and kidneys. In addition, there were no electron microscopic changes in the kidneys.