Characterization of Diabetic Retinopathy in Two Mouse Models and Response to a Single Injection of Anti-Vascular Endothelial Growth Factor.

In this study, we characterized diabetic retinopathy in two mouse models and the response to anti-vascular endothelial growth factor (VEGF) injection. The study was conducted in 58 transgenic, non-obese diabetic (NOD) mice with spontaneous type 1 diabetes (n = 30, DMT1-NOD) or chemically induced (n = 28, streptozotocin, STZ-NOD) type 1 diabetes and 20 transgenic db/db mice with type 2 diabetes (DMT2-db/db); 30 NOD and 8 wild-type mice served as controls. Mice were examined at 21 days for vasculopathy, retinal thickness, and expression of genes involved in oxidative stress, angiogenesis, gliosis, and diabetes. The right eye was histologically examined one week after injection of bevacizumab, ranibizumab, saline, or no treatment. Flat mounts revealed microaneurysms and one apparent area of tufts of neovascularization in the diabetic retina. Immunostaining revealed activation of Müller glia and prominent Müller cells. Mean retinal thickness was greater in diabetic mice. RAGE increased and GFAP decreased in DMT1-NOD mice; GFAP and SOX-9 mildly increased in db/db mice. Anti-VEGF treatment led to reduced retinal thickness. Retinas showed vasculopathy and edema in DMT1-NOD and DMT2-db/db mice and activation of Müller glia in DMT1-NOD mice, with some response to anti-VEGF treatment. Given the similarity of diabetic retinopathy in mice and humans, comparisons of type 1 and type 2 diabetic mouse models may assist in the development of new treatment modalities.

Histological and molecular characterization of glaucoma model induced by one or two injections of microbeads to the anterior chamber of mice.

PURPOSE: To characterize glaucoma-induced damage following injections of plastic microbeads into the anterior chamber of mice. METHODS: Mice were divided into three groups: a single plastic microbeads injection (n = 21); two consecutive plastic microbead injections to the right eye at 1-week intervals, 4 of which with two consecutive saline injections in the left eye (n = 15); and an additional control group of two consecutive saline injections at 1-week intervals (n = 6). Intraocular pressure (IOP) was measured weekly. Retinal thickness, ganglion cells (RGCs) and axonal loss, inflammatory and gliosis reactions were measured at week four. Molecular analysis using qRT-PCR in the microbeads injection groups focused on expression levels of inflammation and glaucoma-related genes. RESULTS: Mean IOP following single injection at 4 weeks was significantly elevated compared to baseline in injected eyes (14.5 ± 3.3 mmHg vs. 11.1 ± 2.5 mmHg, respectively, p = 0.003) and not in fellow eyes (13.2 ± 2.9 mmHg vs. 12.2 ± 2.9, respectively, NS). Six (35.3%) bead-injected eyes had IOP ≥ 17 mmHg compared with 2 (11.8%) saline-injected control eyes. Retinal thickness in injected and fellow eyes was 193.7 ± 15.5 µm and 223.9 ± 15.5 µm, respectively (p = 0.03). RGC loss in injected and fellow eyes was 16.0 ± 0.5 and 17.6 ± 0.7 cells per 200 µm, respectively (p = 0.005). Retinal gliosis, axonal loss and inflammatory cell infiltration to the bead-injected eyes were noted. Molecular analysis following double injection showed STAT3 expression decreased in the glaucoma-induced optic nerves (0.69 ± 0.3 vs. 1.16 ± 0.3, p = 0.04), but increased in the glaucoma-induced retinae (p = 0.05) versus saline; retinal IL-1ß decreased significantly (0.04 ± 0.04 vs. 0.36 ± 0.2, p = 0.02). TNF-α, NFkB and SOD-1 expression did not change. CONCLUSION: One/two injections of microbeads elevated IOP, with measurable neuronal damage. An inflammatory response was detected in the injured retina and optic nerve. The therapeutic significance of these findings should be explored.

Heterozygous Pyrin (MEFV) E148Q allele carriers indicate a reduced glaucoma risk for Turkish population: a prospective clinical analysis.

PURPOSE: The MEFV gene encodes pyrin, a protein linked to increased severity of symptoms in Familial Mediterranean Fever (FMF). We consider that inflammation due to MEFV variants would increase eye inflammation and damage aqueous humor regulation. The present study is the first analysis investigating a MEFV (E148Q) variant as a marker protecting from glaucoma. METHODS: In this prospective clinical analyze, we performed detailed gene sequencing focusing on 22 specific regions of the pyrin (MEFV) gene. The study involved two distinct groups: individuals diagnosed with glaucoma (n = 200) and control subjects without glaucoma (n = 100). Both groups were carefully selected to exclude individuals with symptoms or a previous diagnosis of Familial Mediterranean Fever (FMF). The diagnosis of glaucoma for each participant was rigorously established through comprehensive direct ophthalmic examinations. RESULTS: A significant odds ratio for protection against glaucoma was found in carriers of the subclinical E148Q allele (OR:2.22; 95%CI: 1.098-4.485). No significant differences were found for other variants. One mutant E148Q-allele could decrease the probability of glaucoma development by approximately 68,9%. We observed no differences in the genotype frequency between glaucoma and healthy for the other MEFV gene variants. CONCLUSION: The pyrin variant of the MEFV gene resulting in a subclinical phenotype appears to reduce the incidence of glaucoma, and heterozygous pyrin (MEFV) E148Q allele carriers confer protection against glaucoma. It is important to consider the limitations arising from the relatively small number of studies conducted on this topic.

Ocular Effects of Sildenafil in Naïve Mice and a Mouse Model of Optic Nerve Crush.

Purpose: To investigate the potential neuroprotective effect of sildenafil on the ocular circulation in mice with/without optic nerve crush (ONC). Methods: Male adult mice (n = 63) were treated with intravitreal (IVT) sildenafil 24 µg/3 µL, intraperitoneal (IP) sildenafil 24 µg/300 µL, or IP saline immediately before right ONC induction (ONC group). A second group (n = 123) received the same treatments without ONC induction (naïve group). Evaluations included fluorescein angiography (naïve group; day 0), molecular studies (days 1 and 3), and retinal and optic nerve histology (day 21). Results: Maximal retinal vessel dilatation and increased choroidal effusion were detected within 30 minutes of sildenafil injection. In the ONC group, moderate retinal ganglion cell (RGC) loss was noted at 21 days. However, molecular studies showed increased stress induced gene expression (IP superoxide dismutase [SOD]-1: 3.1-fold; heme oxygenase [HO]-1: 5.8-fold; IVT SOD-1: 1.47-fold), proapoptotic gene expression (IP BAX/B-cell lymphoma [BCL]-2 10.8-/2.3-fold), and glial gene expression (IP glial fibrillary acidic protein [GFAP]: 2.8- and myelin basic protein [MBP]: 2.5-fold). In the naïve group, IVT sildenafil was not associated with RGC loss or optic nerve stroke on histology, although in two samples, molecular parameters were compatible with stroke, showing increased gene expression of HO-1 (3.8-fold) and BCL-2 (2.5-fold). In the IP sildenafil subgroup, optic neuropathy was observed in 6/120 optic nerves, including 3 cyan fluorescence protein (CFP)-Thy-1 mice. Levels of antiapoptosis and anti-ischemia genes were decreased (<0.5-fold) except for three outliers. Conclusions: Sildenafil affects retinal and choroidal perfusion in mice. When injected immediately before ONC, molecular parameters showed a preconditioning neuroprotective effect while histologic studies did not. In the absence of ONC, it is associated with neuropathy, possibly dose-dependent.

Comparison of Neuroprotective Effect of Bevacizumab and Sildenafil following Induction of Stroke in a Mouse Model.

To evaluate the effect of bevacizumab and sildenafil on stroke parameters in a mouse model, middle cerebral artery occlusion was induced in male C57Bl/6 mice using an intra-arterial filament method. The filament was removed after 60 minutes, and the mice were immediately given a single intraperitoneal injection of saline, bevacizumab, or sildenafil. An additional group of mice (n = 7) received bevacizumab 6 h after MCAO induction. The mice were euthanized 24 hours later and evaluated for infarct area and brain edema using triphenyltetrazolium chloride staining and ImageJ. In the saline-treated mice (n = 16), total stroke volume was 19.20 ± 6.38 mm(3), mean penumbra area was 4.5 ± 2.03 mm(3), and hemispheric asymmetry was 106.5%. Corresponding values in the bevacizumab group (n = 19) were 17.79 ± 5.80 mm(3), 7.3 ± 3.5 mm(3), and 108.6%; in the delayed (6 h) bevacizumab injected mice (n = 7) they were 9.80 ± 8.00 mm(3), 2.4 ± 2.0 mm(3), and 98.2%; and in the sildenafil group (n = 16) they were 18.42 ± 5.41 mm(3), 5.7 ± 2.02 mm(3), and 109.9%. The bevacizumab group had a significantly larger mean penumbra area when given immediately and smaller total stroke area in both groups than the saline- (p = 0.03) and sildenafil-treated (p = 0.003) groups. Only delayed bevacizumab group had reduced edema. Bevacizumab, injected immediately or delayed after injury, exerts a neuroprotective/salvage effect, whereas immediate treatment with sildenafil does not. Inflammation may play a role in the neuroprotective effect.

Acquired nystagmus as the initial presenting sign of chiasmal glioma in young children.

BACKGROUND/PURPOSE: The aim of the study was to investigate the incidence of nystagmus at diagnosis in children with optic pathway glioma involving the chiasm and hypothalamus. METHODS: Twenty-two patients with a measurable optic pathway/hypothalamic glioma (without neurofibromatosis-1) were followed in our center from 2001 to 2013. The medical files were retrospectively reviewed for demographic and clinical findings, and the imaging scans, for tumor characteristics. RESULTS: There were 9 boys and 13 girls of mean age 3.5 ± 4.4 years at diagnosis; 15 were aged <2 years. Tumor size ranged from 10 × 6 mm to 62 × 29 mm. Mean duration of follow-up was 8.3 ± 5.4 years. Nystagmus was detected at diagnosis in 10 children (45%), all <2 years old (66.6% of the younger group); no child older than 2 years presented with nystagmus. Nystagmus, once present, did not resolve and continued throughout follow-up. There were no cases of new onset of nystagmus during follow-up in the children in whom it was not detected at diagnosis. Treatment consisted of partial resection/biopsy with/without shunting (n = 13) and chemotherapy (n = 19) with (n = 2) or without adjuvant radiation. Of the 22 children, 6 had a radiographic response to treatment, 8 remained stable, and 8 (all of whom received chemotherapy) showed disease progression despite treatment. CONCLUSION: In conclusion, monocular nystagmus is a more common presenting sign of optic pathway/hypothalamic glioma in children <2 years old than previously estimated. Although subtle, nystagmus has a very narrow differential diagnosis, and its presence should raise suspicions of a chiasmal tumor with prompt referral for imaging. The visual prognosis is moderate to poor.

Determination of formaldehyde levels in 100 furniture workshops in Ankara.

One of the airborne pollutants in wood products industry is formaldehyde, which may pose some health effects. Therefore this study is conducted to determine formaldehyde levels in 100 furniture-manufacturing workshops in Ankara and also to determine the symptoms, which may be related with formaldehyde exposure among the workers. Indoor formaldehyde levels ranged from 0.02 ppm to 2.22 ppm with a mean of 0.6 +/- 0.3 ppm. Outdoor formaldehyde levels also ranged from 0.0 ppm to 0.08 ppm with a mean of 0.03 +/- 0.03 ppm. Formaldehyde levels were higher in workplaces located at basement than in workplaces located at or above ground level (p < 0.01). An association was found between indoor formaldehyde levels and the types of fuel used (p < 0.05). The levels were higher in workplaces where only sawdust was used for heating, than in workplaces where wood, coal, and sawdust are used (p = 0.02). An association was found between runny nose and indoor formaldehyde levels (p = 0.03). Formaldehyde levels were lower in workplaces where employees had no symptoms than in those where employees had 4 or more symptoms (p = 0.02). Of 229 employees 57 subjects (24.9%) work under the formaldehyde levels of 0.75 ppm and above. Thus, approximately one fourth of the employees in workplaces are working in environments with formaldehyde levels exceeding those permitted by Occupational Safety and Health Administration (OSHA). The employees working in small-scale furniture workshops are at risk of formaldehyde exposure. Measures, such as improved ventilation, have to be taken in these workplaces, in order to decrease the formaldehyde levels.