Metformin protects against retinal cell death in diabetic mice.

Retinal degeneration is an early feature of diabetic retinopathy, the major cause of blindness in the developed world. Here we investigated how the widely used antidiabetic drug metformin reduces retinal injury in diabetic mice. Metformin was orally administered to control mice or mice with streptozotocin-induced diabetes. Western blot analysis showed that levels of O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT) and other related proteins such as carbohydrate-responsive element-binding protein (ChREBP) and thioredoxin-interacting protein (TXNIP) were significantly increased, and nuclear factor kappaB (NF-κB) and poly (ADP-ribose) polymerase (PARP) were activated in the diabetic retinas or retinal pigment epithelial (RPE) cells exposed to high glucose compared to controls. More importantly, RPE cells exposed to high glucose and treated with thiamet-G had higher levels of those proteins, demonstrating the role of elevated O-GlcNAcylation. Double immunofluorescence analysis revealed increased co-localization of terminal deoxynucleotide transferase-mediated dUTP nick-end labelling (TUNEL)-positive ganglion cells and OGT, ChREBP, TXNIP, or NF-κB in diabetic retinas compared to control retinas. Co-immunoprecipitation analysis showed that interaction between OGT and ChREBP or NF-κB was increased in diabetic retinas compared to control retinas, and this was accompanied by more cell death. Notably, metformin attenuated the increases in protein levels; reduced co-localization of TUNEL-positive ganglion cells and OGT, ChREBP, TXNIP, or NF-κB; and reduced interaction between OGT and ChREBP or NF-κB. Our results indicate that OGT inhibition might be one of the mechanisms by which metformin decreases retinal cell death.

Ascorbic acid concentrations in aqueous humor after systemic vitamin C supplementation in patients with cataract: pilot study.

BACKGROUND: To measure ascorbic acid concentration in aqueous humor of patients with cataract after oral or intravenous vitamin C supplementation. METHODS: Forty-two eyes of 42 patients with senile cataract who underwent uncomplicated cataract surgery were enrolled. Patients (n = 14 each) were administered oral vitamin C (2 g), intravenous vitamin C (20 g) or no treatment (control group) on the day before surgery. Samples of aqueous humor (0.1 cm3) were obtained by anterior chamber aspiration at the beginning of surgery and stored at -80 °C. Ascorbic acid concentration in aqueous humor was measured by high-pressure liquid chromatography. RESULTS: The mean age at surgery was 62.5 years, with no difference among the three groups. The mean ± standard deviation concentrations of ascorbic acid in aqueous humor in the control and oral and intravenous vitamin C groups were 1347 ± 331 µmol/L, 1859 ± 408 µmol/L and 2387 ± 445 µmol/L, respectively. Ascorbic acid concentration was significantly lower in the control than in the oral (P < 0.01) and intravenous (P < 0.001) vitamin C groups and was significantly higher in the intravenous than in the oral vitamin C group (P < 0.05). CONCLUSIONS: Ascorbic acid concentration in aqueous humor is increased by systemic vitamin C supplementation, with intravenous administration being more effective than oral administration.

Aralia elata prevents neuronal death by downregulating tonicity response element binding protein in diabetic retinopathy.

BACKGROUND/AIMS: The present study addresses the role of tonicity response element binding protein (TonEBP) in retinal ganglion cell (RGC) death in diabetic retinopathy and the impact of Aralia elata extract on the TonEBP/RGC interaction. METHODS: Diabetes was induced in C57BL/6 mice by intraperitoneal injection of streptozotocin (STZ). Control mice received phosphate-buffered saline. After five injections of STZ or saline buffer, A. elata extract was administered by daily oral tube feeding for 7 weeks. All mice were killed at 2 months after the last injection of STZ or saline and the extent of cell death together with the protein expression levels of TonEBP, aldose reductase (AR) and nuclear factor-kappa B (NF-κB) were examined. RESULTS: Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive signals were colocalized with TonEBP-immunoreactive RGCs. The apoptotic cell death of RGCs and the expression levels of TonEBP, AR and NF-κB were significantly increased in the retinas of diabetic mice compared with controls at 2 months after the induction of diabetes. However, these changes were effectively blocked by the administration of A. elata extract. CONCLUSIONS: These results indicate that A. elata prevents diabetes-induced RGC apoptosis and downregulates TonEBP expression. Therefore, A. elata extract may have therapeutic potential to prevent diabetes-induced retinal neurodegeneration in diabetic retinopathy.

A case of phacolytic glaucoma with anterior lens capsule disruption identified by scanning electron microscopy.

BACKGROUND: Phacolytic glaucoma is induced by lens protein or macrophages that have leaked through a macroscopically intact anterior lens capsule. Here, we report a case of phacolytic glaucoma with anterior lens capsule disruptions visualized by scanning electron microscopy (SEM). CASE PRESENTATION: A 71-year-old man was referred to our institute for increased intraocular pressure (IOP) in the right eye. Slit-lamp biomicroscopic examination revealed corneal edema, the presence of inflammatory cells and iridescent crystalline in the anterior chamber, and a hypermature cataract in the right eye. Despite treatment with topical glaucoma medication (0.15% brimonidine, 1% brinzolamide/0.5% timolol, and 0.03% bimatoprost) and systemic mannitol, his IOP remained uncontrolled. Light microscopy was used to examine the aqueous humor obtained via anterior chamber paracentesis and the anterior lens capsule obtained via intracapsular cataract extraction (ICCE), which revealed that the anterior lens capsule was intact. However, SEM revealed full-thickness disruptions in the anterior lens. CONCLUSION: This is the first reported case of phacolytic glaucoma with disruptions of the anterior lens capsule confirmed by SEM.

A novel forkhead box C1 gene mutation in a Korean family with Axenfeld-Rieger syndrome.

PURPOSE: To report a case series of patients with novel forkhead box CI (FOXC1) mutations in a Korean family with Axenfeld-Rieger syndrome (ARS). METHODS: Four members of the same family underwent complete ophthalmologic and systemic examinations and genetic analysis. Genomic DNA was isolated from peripheral blood leukocytes, and all coding exons with flanking intronic regions of the FOXC1 and pituitary homeobox 2 genes were amplified using PCR, and sequenced. RESULTS: The patients were 40, 12, 11, and 10 years old (father, son, and two sisters, respectively). All four had uncontrolled intraocular pressure, glaucomatous visual field defect, retinal nerve fiber layer defect, iridocorneal adhesion on gonioscopy, hypoplasia and marked atrophy of the iris, flattening of the midface, and broad flat noses. A diagnosis of ARS was made based on characteristic ocular and systemic traits. A novel FOXC mutation, c.317delA, was identified in all affected members of the family with ARS. CONCLUSIONS: We found a novel c.317delA mutation in FOXC1 in a Korean family with ARS. We suggest that this FOXC1 mutation causes typical ARS, and that our results may be useful for better understanding of the spectrum of FOXC1 mutations and the role of FOXC1 in the development and progression of ARS.

A Case of Invasive Aspergillosis Presenting as Acute Angle Closure Glaucoma.

Purpose: To report a case of invasive aspergillosis presenting as acute angle closure glaucoma. Case: A 72-year-old male patient visited our clinic with decreased visual acuity and ocular pain on the right eye lasting for 3 d. His intraocular pressure was 42 mmHg in the right eye and 18 mmHg in the left eye. And, there was about 2 mm of exophthalmos, slight ptosis with decreased motility in all directions, conjunctival injection, moderate mydriasis with a relative afferent pupillary defect, and angle closure in the right eye. Orbital computed tomography and magenetic resonance imaging showed isotense mass involving right orbit and ethmoid sinus. Based on the biopsy, invasive aspergillosis was definitely diagnosed. Despite perfoming peripheral laser iridotomy and administrating antifungal agent and antiglaucoma medication, the patient was blinded in his right eye. During the follow-up period, visual acuity in the left eye suddenly decreased due to the invasive aspergillosis in the left paranasal sinus and optic nerve, and eventually the patient lost his left vision as well. Conclusion: This report is regarding a case of an invasive aspergillosis resulting in blindness in both eyes with the clinical manifestations of acute angle closure caused by invasive aspergillosis.

Two cases of human thelaziasis and brief review of Korean cases.

The present study was performed to describe 2 cases of human thelaziasis (HT) which occurred in Gyeongsangnam- do and to briefly review the previously reported Korean cases. A 58-year old woman, residing in Hadong-gun, Gyeongsangnam-do, came to Gyeongsang National University Hospital (GNUH) complaining of foreign body sensation and itching of the right eye in March 2000. Total 6 adult nematodes of Thelazia callipaeda (2 males and 4 females) were detected in her right eye. A 80-year old man, residing in Jinju-si, Gyeongsangnam-do, came to GNUH complaining of foreign body sensation, itching, and pain of the right eye in December 2007. A total of 5 worms (4 females and 1 degenerated) were removed from his right eye. We analyzed characteristics of the total 39 Korean HT cases reported to date, including the present 2 cases. Most of the cases (71.8%) occurred in Seoul and Gyeonggi-do before 2000, and 21 cases (53.8%) were males and 18 (46.2%) were females. The prevalence was higher in younger ages below 30 years (48.7%) than 31-60 years (41.0%) and over 61 years (10.3%). The seasonal prevalence showed a higher incidence in autumn (43.6%) than in other seasons. Most of the cases (94.9%) were conjunctival sac infections and only 2 (5.1%) were intraocular cases. The present 2 HT cases are the first reported cases in Gyeongsangnam-do. Some characteristics of Korean HT cases were analyzed.

Calcineurin mediates AKT dephosphorylation in the ischemic rat retina.

Calcineurin (CaN) is a calcium/calmodulin-dependent protein phosphatase that has an important role in ischemia-induced apoptosis. The serine/threonine kinase, Akt, which is also known as protein kinase B, has an important role in the cell death/survival pathways. Akt is activated by its phosphorylation, which is positively regulated by phosphatidylinositol 3-kinase (PI3K) and negatively regulated by a class of protein phosphatases (PPs) in tissue. However, the relationship between CaN and Akt after transient ischemia remains unclear. In the present study, we investigated whether CaN is involved in neuronal cell apoptosis and Akt dephosphorylation that occur during ischemic injury. We examined the interdependence between CaN and Akt/protein kinase B (PKB) in the rat retina after transient ischemia. After ischemic damage, we detected changes in levels of CaN, Akt and Bad in rats in the presence or absence FK506, CaN inhibitor. Our results show that CaN cleavage reduced Akt phosphorylation at Thr308 and Ser473, and led to apoptosis via dephosphorylation of the proapoptotic Bcl-2 family member Bad. After treatment with FK506, Akt and Bad dephosphorylation was greatly reduced. The total number of TUNEL-positive neurons was reduced by intravitreal injection of FK506 after transient ischemia. These results indicate that CaN cleavage negatively regulates Akt phosphorylation and is involved in retinal cell apoptosis after transient ischemia.

Comparison of anterior segment optical coherence tomography findings in acanthamoeba keratitis and herpetic epithelial keratitis.

This study is to investigate the characteristic features of Acanthamoeba keratitis (AK) that differentiating it from herpetic epithelial keratitis (HEK) using anterior segment optical coherence tomography (AS-OCT). Medical records of three eyes of each AK and herpetic keratitis who had AS-OCT examination were reviewed in this study. Slit-lamp biomicroscopy and AS-OCT was performed on the initial visit and on every follow-up visits in all patients. In all three AK cases, reflective bands in the corneal stroma that correspond to the area of radial keratoneuritis were observed. The depth of the reflective bands varied in each case. After AK treatment, slit-lamp biomicroscopy confirmed that radial keratoneuritis had resolved and AS-OCT confirmed that reflective bands in the corneal stroma had also disappeared in all patients. Unlike the AS-OCT results found in AK, highly reflective HEK lesions were observed only in the subepithelial area, not in the stroma. AS-OCT seems to be helpful analyzing the specific depth of the lesion which enables to distinguish AK from HEK.

Extensive Submacular Hemorrhage After Trabeculectomy With Mitomycin C.

PURPOSE: We report the occurrence of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult choroidal neovascular membrane (CNVM). PATIENTS AND METHODS: A 66-year-old man had a 3-year history of primary open-angle glaucoma in the left eye, which had been treated with topical antiglaucoma medication. The patient had age-related macular degeneration with an occult CNVM, for which he had received 5 intravitreal injections of ranibizumab and 5 intravitreal injections of bevacizumab in the left eye over a 3-year period. As intraocular pressure was not under control in the left eye over a 2-month period, trabeculectomy with mitomycin C was performed. RESULTS: On the first postoperative day, intraocular pressure was 8 mm Hg with a well-formed bleb in the left eye. However, extensive subretinal hemorrhage was observed, and the patient underwent pneumatic displacement and pars plana vitrectomy to remove the hemorrhage. After 7 months, extensive subretinal fibrosis was observed and visual acuity was low (hand movement only). CONCLUSIONS: To our knowledge, this is the first report of an extensive submacular hemorrhage after trabeculectomy with mitomycin C in a patient with an occult CNVM.

Clinical Features of Herpes Simplex Keratitis in a Korean Tertiary Referral Center: Efficacy of Oral Antiviral and Ascorbic Acid on Recurrence.

PURPOSE: To describe the clinical manifestations of herpes simplex keratitis (HSK) in a tertiary referral center in South Korea and to determine whether ascorbic acid treatment prevents recurrence of herpetic epithelial keratitis. METHODS: This retrospective cohort study included all consecutive patients with herpetic keratitis referred to our center from January 2010 to January 2015. Clinical features, ocular complications, and recurrences were recorded. RESULTS: In total, 149 eyes of the 133 patients (72 male and 61 female) were followed for an average of 24.6 ± 13.2 months. Sixteen (12.0%) patients had bilateral HSK. The most frequent HSK subtype was epithelial keratitis (49.7%), which was followed by stromal keratitis (23.5%). Epithelial keratitis was the most likely subtype to recur. Complications occurred in 122 (81.9%) eyes. The most common complication was corneal opacity. Recurrences were observed in 48 (32.2%) eyes. The recurrence rates were lower in the prophylactic oral antiviral agent group (16 / 48 eyes, 33.3% vs. 49 / 101 eyes, 48.5%) and the ascorbic acid treatment group (13 / 48 eyes, 27.1% vs. 81 / 101 eyes, 70.3%) compared with the groups without medications. Univariate logistic regression analysis revealed that both factors significantly reduced the risk of recurrence (acyclovir: odds ratio, 0.25; 95% confidence intervals, 0.12 to 0.51; ascorbic acid: odds ratio, 0.51; 95% confidence intervals, 0.20 to 0.91). CONCLUSIONS: This retrospective study described the clinical findings of HSK in a tertiary referral center in South Korea. Prophylactic oral antiviral agent treatment and oral ascorbic acid administration may lower the risk of recurrence.

Effect of Nd:YAG Laser Capsulotomy on Anterior Segment Parameters in Patients with Posterior Capsular Opacification after Phacovitrectomy.

PURPOSE: To compare changes in anterior segment parameters after Nd:YAG laser capsulotomy in eyes that underwent either combined phacovitrectomy or cataract surgery. METHODS: This retrospective study enrolled 37 eyes of 35 patients with posterior capsular opacification treated with combined phacovitrectomy (group A), and 35 eyes of 32 patients with posterior capsular opacification treated with cataract surgery (group B). Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber angle, and anterior chamber volume, were measured by a Pentacam before Nd:YAG laser capsulotomy and 1 hour, 1 day, 1 week, 1 month, and 3 months after this treatment. RESULTS: In the cataract surgery group, the ACD was significantly lower 1 day (3.75 ± 0.74 mm), 1 week (3.73 ± 0.24 mm), and 3 months (3.74 ± 0.33 mm) after Nd:YAG laser capsulotomy compared with the pretreatment value (4.20 ± 0.62 mm, p = 0.002). By contrast, the ACD did not change significantly over time in the combined phacovitrectomy group. The ACD differed significantly between the two groups at 1 week, 1 month, and 3 months after capsulotomy. There were no significant changes in the anterior chamber volume, anterior chamber angle, central corneal thickness, or pupil size from before to after capsulotomy in either group. A non-significant trend toward myopic shift was observed in group A (p = 0.072) and B (p = 0.055). CONCLUSIONS: The results of the present study may help determine the power of the intraocular lens in patients who underwent combined surgery or cataract surgery and who will receive Nd:YAG laser capsulotomy.

Citicoline reduces upregulated clusterin following kainic acid injection in the rat retina.

PURPOSE: To investigate the effects of citicoline on upregulated clusterin and retinal damage induced by kainic acid (KA). METHODS: KA was injected into the vitreous of rats. Effects of systemic citicoline treatments were estimated by measuring the thickness of the various retinal layers, immunoblotting, and immunohistochemical techniques. RESULTS: One day after KA injection, the immunoreactivity of clusterin increased significantly. In rats treated with KA plus citicoline, clusterin immunoreactivity was markedly reduced compared to KA-treated rats. Western blot analysis showed that clusterin protein levels were increased in KA-treated rats, but decreased in KA plus citicoline-treated rats. Apoptotic cell death was determined by TUNEL method. Citicoline reduced the expression of clusterin, as well as the expression of TUNEL after KA injection in the rat retina. CONCLUSION: The increased expression of clusterin following KA injection in the rat retina suggests the presence of neurodegenerative events; citicoline may provide neuroprotection against neuronal cell damage.

Ultraviolet B Radiation Stimulates the Interaction between Nuclear Factor of Activated T Cells 5 (NFAT5) and Nuclear Factor-Kappa B (NF-κB) in Human Lens Epithelial Cells.

PURPOSE: Nuclear factor-kappa B (NF-κB) has been proposed as a therapeutic target for the treatment of cataracts. The authors investigated the relationship between nuclear factor of activated T cells 5 (NFAT5) and NF-κB in ultraviolet B (UVB)-irradiated human lens epithelial (HLE) cells. METHODS: Human lens epithelial B-3 (HLE-B3) cells were exposed to UVB light at a dose of 10 mJ/cm2 and then incubated for 24 h. Cell viability was assessed by using the Cell Counting Kit-8 (CCK-8) assay. Gene expression level of NFAT5 was determined using real-time quantitative polymerase chain reaction (qPCR). Protein expression levels of NFAT5, NF-κB p65, and α-smooth muscle actin (α-SMA) and the association of NFAT5 with the NF-κB p65 subunit were measured by Western blot analysis and a co-immunoprecipitation assay, respectively. The cellular distribution of NFAT5 and NF-κB p65 was examined by triple immunofluorescence staining. RESULTS: At 24 h after UVB exposure, cell viability significantly decreased in a dose-dependent manner, and UVB light (15 and 20 mJ/cm2) significantly increased the ROS generation. UVB irradiation increased NFAT5 mRNA and protein levels and increased phosphorylation of NF-κB in HLE-B3 cells. α-SMA protein levels were increased in the irradiated cells. In addition, NFAT5 and NF-κB translocated from the cytoplasm to the nucleus, and binding between the p65 subunit and NFAT5 was increased. CONCLUSIONS: Exposure to UVB radiation induces nuclear translocation and stimulates binding between NFAT5 and NF-κB proteins in HLE-B3 cells. These interactions may form part of the biochemical mechanism of cataractogenesis in UVB-irradiated HLECs.

Aralia elata inhibits neurodegeneration by downregulating O-GlcNAcylation of NF-κB in diabetic mice.

AIM: To investigate the role of O-GlcNAcylation of nuclear factor-kappa B (NF-κB) in retinal ganglion cell (RGC) death and analysedthe effect of Aralia elata (AE) on neurodegeneration in diabetic mice. METHODS: C57BL/6mice with streptozotocin-induced diabetes were fed daily with AE extract or control (CTL) diet at the onset of diabetes mellitus (DM). Two months after injection of streptozotocin or saline, the degree of cell death and the expression of O-GlcNAc transferase (OGT), N-acetyl-b-D-glucosaminidase (OGA), O-GlcNAcylated proteins, and O-GlcNAcylation of NF-κB were examined. RESULTS: AE did not affect the metabolic status of diabetic mice. The decrease in the inner retinal thickness (P<0.001 vs CTL, P<0.01 vs DM) and increases in RGCs with terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (P<0.001 vs CTL, P<0.0001 vs DM), glial activation, and active caspase-3 (P<0.0001 vs CTL, P<0.0001 vs DM) were blocked in diabetic retinas of AE extract-fed mice. Expression levels of protein O-GlcNAcylation and OGT were increased in diabetic retinas (P<0.0001 vs CTL), and the level of O-GlcNAcylation of the NF-κB p65 subunit was higher in diabetic retinas than in controls (P<0.0001 vs CTL). AE extract downregulated O-GlcNAcylation of NF-κB and prevented neurodegeneration induced by hyperglycemia (P<0.0001 vs DM). CONCLUSION: O-GlcNAcylation of NF-κB is concerned in neuronal degeneration and that AE prevents diabetes-induced RGC apoptosis via downregulation of NF-κB O-GlcNAcylation. Hence, O-GlcNAcylation may be a new object for the treatment of DR, and AE may have therapeutic possibility to prevent diabetes-induced neurodegeneration.

Aralia elata (Miq) Seem Extract Decreases O-GlcNAc Transferase Expression and Retinal Cell Death in Diabetic Mice.

Aralia elata (Miq) Seem (AES) is a medicinal plant used in traditional Chinese and Korean medicine for the treatment of several diseases, including diabetes. This study aimed to investigate the neuroprotective effect of AES extract against high glucose-induced retinal injury in diabetic mice. AES extract (20 and 100 mg/kg body weight) was orally administered to control mice or mice with streptozotocin-induced diabetes. Protein levels of O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT), carbohydrate-responsive element-binding protein (ChREBP), sterol regulatory element-binding protein (SREBP)-1, thioredoxin-interacting protein (TXNIP), fatty acid synthase (FAS), and acetyl CoA carboxylase (ACC) were analyzed by western blotting. Colocalization of terminal deoxynucleotide transferase-mediated dUTP nicked-end labeling (TUNEL)-positive ganglion cells and OGT, ChREBP, or TXNIP were monitored using double immunofluorescence analysis. Interaction between ChREBP and OGT was assessed using coimmunoprecipitation analysis. AES extract protected the retinas from neuronal injury and decreased levels of OGT, ChREBP, TXNIP, SREBP-1, FAS, and ACC in the diabetic retinas. AES extract reduced colocalization of TUNEL-positive ganglion cells and OGT, ChREBP, or TXNIP in the diabetic retinas. Coimmunoprecipitation analysis indicated that AES extract reduced interaction between ChREBP and OGT and attenuated ganglion cell death in diabetic retinas. Moreover, the ChREBP that colocalized with OGT or the TUNEL signal was significantly decreased in diabetic mice treated with AES extract. These findings show that AES extract can alleviate OGT-, ChREBP-, TXNIP-, or SREBP-1-related retinal injury in diabetic retinopathy.

Protective effects of betaxolol in eyes with kainic acid-induced neuronal death.

In the present study, we investigated whether betaxolol, a selective beta1-adrenoceptor antagonist, has neuroprotective effect on kainic acid (KA)-induced retinal damage. Neurotoxicities were induced in adult male rats by intravitreal injection of KA (total amount, 6 nmol). To examine the neuroprotective effects of betaxolol, rats were pretreated with betaxolol topically 60 min before KA injection to the rat eyes and twice daily for 1, 3, and 7 days after KA injection. The neuroprotective effects of betaxolol were estimated by measuring the thickness of the various retinal layers, and by counting the number of choline acetyltransferase (ChAT)- and tyrosine hydroxylase (TH)-positive cells in each retinal layer. The retina is highly vulnerable to KA-induced neuronal damage. Morphometric analysis of retinal damage in KA injected eyes, the thickness of the retinal layers decreased markedly after KA injection period of both 3 and 7 days. Furthermore, the numbers of ChAT- and TH-positive cells were significantly reduced by intravitreal injection of KA. However, when two drops of betaxolol, once before KA injection and twice daily for 7 days after KA injection, were continuously administered, the reductions in the retinal thickness and the retinal ChAT- and TH-positive cells were significantly attenuated. The present study suggests that topically applied betaxolol has neuroprotective effect on the retinal cell damage due to KA-induced neurotoxicity.

Action of citicoline on rat retinal expression of extracellular-signal-regulated kinase (ERK1/2).

Citicoline is an essential endogenous intermediate in the biosynthesis of phosphatidylcholine, which acts as a therapeutic agent in models of central nervous system injury and neurodegenerative diseases. The present study investigated the effects of citicoline on extracellular-signal-regulated kinase 1/2 (ERK1/2) expression in the rat retina after kainic acid (KA) treatment. KA (6 nmol) was injected into the vitreous of the rat eyes. The animals were then injected intraperitoneally with citicoline (500 mg/kg) twice daily after the KA injection. The neuroprotective effects of citicoline were estimated by evaluating temporal changes in ERK1/2 using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL), immunoblotting and immunohistochemical techniques. The expression of phosphorylated ERK1/2 was slightly decreased after 6 h, and significantly reduced after 12 h, in the rats receiving the KA injection plus citicoline treatment. Our results demonstrated that citicoline decreased the activation of ERK1/2 due to the KA treatment, suggesting that it exerts its neuroprotective activity by reducing the concentrations of proteins involved in apoptosis.

The Change of Lacrimal Gland Volume in Korean Patients with Thyroid-associated Ophthalmopathy.

PURPOSE: To describe the change of lacrimal gland volumes in Korean patients with thyroid-associated ophthalmopathy (TAO) via computed tomography (CT). METHODS: A retrospective review of CT images from 217 TAO patients and 135 control subjects was performed. The TAO patients were diagnosed between May 2005 and May 2014 and had a CT performed on initial presentation (330 orbital CT scans). These images were compared with 270 orbital CT scans from the control group, obtained between May 2013 and May 2014. An open source DICOM viewer was used to calculate the volume of the lacrimal gland. RESULTS: The mean volume of the lacrimal gland in TAO patients was 0.816 cm3 in the right orbit (standard deviation [SD], 0.048) and 0.811 cm3 in the left orbit (SD, 0.051), with no significant difference between right and left (p = 0.192). However, significant differences were observed between TAO patients and healthy individuals (p < 0.001). There was no significant difference between mean lacrimal gland volumes of males (0.812 cm3; SD, 0.037) and females (0.816 cm3; SD, 0.029) (p = 0.513). There was a negative correlation between gland volume and age in TAO patients (Pearson r = -0.479, p = 0.00). The subjective tearing (right: r = 0.244, p = 0.018; left: r = 0.226, p = 0.024), corneal superficial punctate keratopathy (right: r = 0.192, p = 0.040; left: r = 0.206, p = 0.036), and exophthalmometry (right: r = 0.182, p = 0.032; left: r = 0.180, p = 0.046) correlated with lacrimal gland volume. CONCLUSIONS: This study is the first to use CT images to calculate the lacrimal gland volume of Korean TAO patients. In TAO patients, the lacrimal gland volume was notably increased compared to control subjects. The lacrimal gland volume decreased with age, but there was no difference between gender and no difference between left and right. The lacrimal gland volume correlated with subjective tearing, corneal superficial punctate keratopathy and exophthalmometry.

Increased O-GlcNAcylation of NF-κB Enhances Retinal Ganglion Cell Death in Streptozotocin-induced Diabetic Retinopathy.

PURPOSE: Hyperglycemia results in increased flux through the hexoxamine biosynthetic pathway. We examined whether hyperglycemia increases O-GlcNAcylation in the diabetic retina and whether elevated O-GlcNAcylation of nuclear factor (NF)-κB increases apoptosis of retinal ganglion cells (RGCs) in diabetic retinopathy (DR). MATERIALS AND METHODS: Diabetes was induced in C57BL/6 mice by five consecutive intraperitoneal injections of 55 mg/kg streptozotocin. All mice were killed 2 months after injections and expression levels of O-GlcNAcylated proteins, O-linked N-acetylglucosamine transferase (OGT), ß-d-N-acetylglucosaminidase and NF-κB, and the extent of RGC death were examined. Immunoprecipitations were performed to investigate whether O-GlcNAcylation of NF-κB led to its activation and RGC death in DR. RESULTS: The expression levels of O-GlcNAcylated proteins and OGT were markedly higher in diabetic retinas than in control retinas. OGT colocalized with NeuN, a RGC-specific marker, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells in the ganglion cell layer of diabetic retinas. The p65 subunit of NF-κB was O-GlcNAcylated and the level of O-GlcNAcylated p65 was higher in diabetic retinas than in control retinas. CONCLUSION: The present data suggest that hyperglycemia increases O-GlcNAcylation in DR and that O-GlcNAcylation of the p65 subunit of NF-κB is involved in hyperglycemia-induced NF-κB activation and RGC death in DR.