The effect of long-term systemic immunosuppressive drug use on druse formation: a new perspective to age-related macular degeneration

Background/aim

To evaluate the effect of the long-term use of systemic immunosuppressive drugs on druse formation in patients aged over 50 years.

Materials and methods

The current retrospective cohort study includes 420 eyes of 420 patients. 210 eyes of 210 patients who used immunosuppressive drugs (Group 1) at least for the last 5 years and 210 eyes of 210 control patients (Group 2) who did not use any drugs were compared. All patients were older than 50 years and selected among patients who were followed by rheumatology and ophthalmology clinic at a tertiary university hospital. All patients had complete ophthalmic examination, fundus photography and optical coherence tomography (OCT). The primary outcome of this study is the difference in macular and paramacular druse formation rates between two groups.

Results

Small, intermediate, large, soft, and paramacular druse formation rates were significantly lower in Group 1 than those in Group 2 (P = 0.028, P = 0.001, P = 0.001, P = 0.001, and P = 0.001, respectively).

Conclusion

Patients who used long-term systemic immunosuppressive drugs had significantly lower hard and soft druse formation rate than age and sex matched control subjects.

The Effect of Orally Administered Dronabinol on Optic Nerve Head Blood Flow in Healthy Subjects-A Randomized Clinical Trial

It has been hypothesized that besides its intraocular pressure (IOP) lowering potential, tetrahydrocannabinol (THC) may also improve ocular hemodynamics. The aim of the present study was to investigate whether single oral administration of dronabinol, a synthetic THC, alters optic nerve head blood flow (ONHBF) and its regulation in healthy subjects. The study was carried out in a randomized, placebo-controlled, double-masked, two-way crossover design in 24 healthy subjects. For each study participant, 2 study days were scheduled, on which they either received capsules containing 5 mg dronabinol or placebo. ONHBF was measured with laser Doppler flowmetry at rest and while the study participants performed isometric exercise for 6 minutes to increase mean arterial blood pressure (MAP). This was repeated 1 hour after drug intake. Ocular perfusion pressure (OPP) was calculated as 2/3MAP-IOP. Dronabinol was well tolerated and no cannabinoid-related psychoactive effects were reported. Neither administration of dronabinol nor placebo had an effect on IOP, MAP, or OPP. In contrast, dronabinol significantly increased ONHBF at rest by 9.5 ± 8.1%, whereas placebo did not show a change in ONHBF (0.3 ± 7.4% vs. baseline, P < 0.001 between study days). Dronabinol did not alter the autoregulatory response of ONHBF to isometric exercise. In conclusion, the present data indicate that low-dose dronabinol increases ONHBF in healthy subjects without affecting IOP, OPP, or inducing psychoactive side effects. In addition, dronabinol does not alter the autoregulatory response of ONHBF to an experimental increase in OPP. Further studies are needed to investigate whether this effect can also be observed in patients with glaucoma.

Assessment of changes in the macula and optic nerve head using optical coherence tomography in patients with attention deficit hyperactivity disorder

INTRODUCTION

To assess if there are any differences in macular and papillary thickness using optical coherence tomography (OCT) in patients with attention deficit hyperactivity disorder (ADHD) compared with a control group, including if there are differences between ADHD patients with and without treatment.

METHODS

Prospective observational study including 92 eyes of 46 patients divided into 2 groups: 46 eyes of 23 patients with ADHD, and a control group of 46 eyes of 23 healthy patients. The group of patients with ADHD was subdivided into those on treatment with methylphenidate (n=28) and those not on treatment (n=18). The macular thickness, the ganglion cell complex (GCC), and the retinal nerve fibre layer (RNFL) at the papillary level were measured in 12 sectors.

RESULTS

A lower central macular thickness was observed in the ADHD patients than in the controls (257.4±20μm versus 267.5±20μm, P=.013), with no differences observed in the GCC (P=.566), or in the RNFL (P=.095). There were no differences in the patients with ADHD with and without treatment, as regards macular thickness and the GCC (P=.160 and P=.375 respectively), but a lower foveal thickness (P=.018) and RNFL in 5/12 sectors at the papillary level (P=.033) were observed in those without treatment.

CONCLUSIONS

A lower macular thickness was observed in patients with ADHD than in controls. In addition, patients with ADHD without treatment had a lower thickness of the fovea and RNFL than those patients on treatment.

Changes in Ocular Blood Flow after Ranibizumab Intravitreal Injection for Diabetic Macular Edema Measured Using Laser Speckle Flowgraphy

PURPOSE

To evaluate the effects of intravitreal ranibizumab (IVR) treatment on the blood flow of the optic nerve head (ONH) and of retinal vessels of the peripapillary region of eyes with diabetic macular edema (DME) assessed using laser speckle flowgraphy (LSFG).

METHODS

Forty eyes of 30 patients treated with IVR for DME were included in this prospective clinical study. Mean blur rate (MBR) and relative flow volume (RFV) of the ONH and of a superior retinal artery and an inferior retinal vein of the peripapillary region were measured using LSFG at baseline, 2 weeks (T1), and 1 month (T2) after IVR injection. In addition, best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured in all cases.

RESULTS

The BCVA improved and CRT decreased significantly during the follow-up period (p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA, p < 0.010). MBR-related parameters of the ONH such as MBR of all area (MA), MBR of vascular area (MV), and MBR of tissue area (MT) decreased significantly at 2 weeks after IVR compared to baseline values (MA.

CONCLUSION

IVR injection leads to a reduction of ocular blood flow both in the ONH and in the retinal peripapillary vessels associated with peripapillary vessel constriction. The reduction of CRT and related improvement of vision may be related to the changes in ocular blood flow.

Effects of ripasudil, a rho kinase inhibitor, on blood flow in the optic nerve head of normal rats

PURPOSE

To evaluate the effect of topically administrated ripasudil, a rho kinase inhibitor, on blood flow in the optic nerve head (ONH) of normal rats.

METHODS

Ripasudil (0.4%) or placebo was administered in the right eye of normal Brown Norway rats in a double-blind manner. Laser speckle flowgraphy was measured in the ONH of the right eye 20 or 40 min after a single instillation and before and after 7 or 14 days of twice daily instillation. Mean blur rate was evaluated in the total area (MA), the vessel region (MV), and the tissue region (MT). Intraocular pressure (IOP), blood pressure, ocular perfusion pressure (OPP), and heart rate were also recorded at each time point.

RESULTS

After a single instillation, MV was significantly larger at 40 min than 20 min in the ripasudil group (P = 0.044) and was significantly lower in the placebo group (P = 0.023). MA and MV 40 min after instillation were significantly larger in the ripasudil group than in the placebo group (P = 0.022 and P = 0.006, respectively). After continuous instillation, MA and MV in the ripasudil group significantly increased from baseline after 7 and 14 days of treatment (both P < 0.05) and MA, MV, and MT were significantly higher than in the placebo group (MA: 7 and 14 days, P < 0.01; MV: 7 days, P = 0.003, and 14 days, P = 0.012; MT: 7 days, P = 0.046). There were no significant changes in IOP, blood pressure, or OPP after single or continuous instillation.

CONCLUSIONS

Topical instillation of ripasudil increased blood flow around the ONH in the eyes of normal rats.

A Small Molecule TrkB Neurotrophin Receptor Partial Agonist as Possible Treatment for Experimental Nonarteritic Anterior Ischemic Optic Neuropathy

PURPOSE

Brain-derived neurotrophic factor (BDNF) and activation of its high affinity receptor tropomyosin kinase (Trk) B promote retinal ganglion cells (RGCs) survival following injury. In this study, we tested the effects of LM22A-4, a small molecule TrkB receptor-specific partial agonist, on RGC survival in vitro and in experimental nonarteritic anterior ischemic optic neuropathy (AION), the most common acute optic neuropathy in those older than 50 years.

METHODS

We assessed drug effects on immunopanned, cultured RGCs and calculated RGC survival and assessed TrkB receptor activation by mitogen-activated protein (MAP) kinase translocation. To assess effects in vivo, we induced murine AION and treated the animals with one intravitreal injection and three-week systemic treatment. We measured drug effects using serial spectral-domain optical coherence tomography (OCT) and quantified retinal Brn3A+ RGC density three weeks after ischemia.

RESULTS

In vitro, LM22A-4 significantly increased the survival of cultured RGCs at day 2 (95% CI control: 8.4-13.6; LM22A-4: 23.7-30.3; BDNF: 24.3-29.9; P ≤ 0.0001), similar to the effect of the endogenous TrkB receptor ligand BDNF. There was also significant nuclear and cytoplasmic translocation of MAP kinase (95% CI control: 0.9-6.8; LM22A-4: 38.8-84.4; BDNF: 64.0-93.0; P = 0.0002), a known downstream event of TrkB receptor activation. Following AION, LM22A-4 treatment led to significant preservation of the ganglion cell complex (95% CI: AION-PBS: 66.8-70.7%; AION-LM22A-4: 70.0-73.1; P = 0.03) and total retinal thickness (95% CI: AION-PBS: 185-196%; AION-LM22A-4: 195-203; P = 0.002) as measured by OCT compared with non-treated eyes. There was also significant rescue of the Brn3A+ RGC density on morphometric analysis of whole mount retinae (95% CI control: 2360-2629; AION-PBS: 1647-2008 cells/mm2; AION-LM22A-4: 1958-2216 cells/mm2; P = 0.02).

CONCLUSIONS

TrkB receptor partial agonist LM22A-4 promoted survival of cultured RGCs in vitro by TrkB receptor activation, and treatment in vivo led to increased survival of RGCs after optic nerve ischemia, providing support that LM22A-4 may be effective therapy to treat ischemic optic neuropathy.

ABBREVIATIONS

AION: anterior ischemic optic neuropathy, BDNF: Brain-derived neurotrophic factor, GCC: ganglion cell complex, MAP: mitogen-activated protein, OCT: spectral-domain optical coherence tomography, OD: right eye, ON: optic nerve, ONH: optic nerve head, OS: left eye, RGC: retinal ganglion cell; Trk: tropomyosin kinase.

Imaging Technologies for Assessing Neuroprotection in Glaucomatous Optic Neuropathy

The confocal scanning laser ophthalmoscope and the scanning laser polarimeter are two new imaging devices that may be beneficial in the diagnosis and monitoring of glaucoma patients. For each of these instruments, the authors describe benefits and limitations with regard to imaging mechanisms, sensitivity, and clinical applications. In comparison with currently used tests for glaucoma, these instruments provide quantitative assessment of the optic disc and RNFL at the clinic visit, with reduced need for pupil dilation and clear media. They also show promise for improving the ability to monitor progression of glaucomatous optic neuropathy and might allow better assessment of the efficacy of a neuroprotective agent.

Progressive Chronic Retinal Axonal Loss Following Acute Methanol-induced Optic Neuropathy: Four-Year Prospective Cohort Study

PURPOSE

To study the dynamics and clinical determinants of chronic retinal nerve fiber layer thickness (RNFL) loss after methanol-induced optic neuropathy.

DESIGN

Prospective cohort study.

METHODS

All patients underwent complete ophthalmic evaluation including spectral-domain optical coherence tomography 3 times during 4 years of observation: 4.9 (±0.6), 25.0 (±0.6), and 49.9 (±0.5) months after discharge.

PARTICIPANTS

Eighty-four eyes of 42 survivors of methanol poisoning, mean age (standard deviation) of 45.7 (±4.4) years; and 82 eyes of 41 controls, mean age 44.0 (±4.2) years.

MAIN OUTCOME MEASURES

Global and temporal RNFL loss.

RESULTS

Abnormal RNFL thickness was registered in 13 of 42 (31%) survivors of methanol poisoning and chronic axonal loss in 10 of 42 (24%) patients. Significant decrease of global/temporal RNFL thickness during the observation period was found in the study population compared to the controls (P < .001). The risk estimate of chronic global RNFL loss for arterial blood pH < 7.3 at admission was 11.65 (95% confidence interval 1.91-71.12) after adjusting for age and sex. The patients with chronic axonal degeneration demonstrated progressive visual loss in 7 of 10 cases. The patients with abnormal RNFL thickness had magnetic resonance signs of brain damage in 10 of 13 vs 8 of 29 cases with normal RNFL thickness (P = .003). Signs of brain hemorrhages were present in 7 of 13 patients with abnormal RNFL thickness vs 5 of 29 cases with normal RNFL thickness (P = .015).

CONCLUSIONS

Methanol-induced optic neuropathy may lead to chronic retinal axonal loss during the following years. Arterial blood pH on admission is the strongest predictor of chronic RNFL thickness decrease. Chronic retinal neurodegeneration is associated with the progressive loss of visual functions and necrotic brain lesions.

Optic Nerve Hypoplasia in Fetal Alcohol Syndrome: An Update

Optic nerve hypoplasia was detected in up to one half of a group of Swedish children born to alcoholic mothers. Using an experimental model of pre- and postnatal alcohol exposure in rats fed a liquid diet, reduced optic nerve size from gestational day 21 (294 ± 26×102 μm2 vs 502 ± 16×102 μm2; n=6; p≤0.001) to later in development was observed as a result of the daily mean blood alcohol levels achieved in dams and their offspring. Altered glial cells and degenerating and atrophic optic axons, myelin sheaths and ganglion cells were frequent in the alcohol-exposed optic nerves.

Smaller optic nerve (1,918 ± 61×102 μm2 vs 2.195 ± 40×102 μm2; n=4; p≤0.001), reduced gaglion cell and axonal densities, and ultrastructural damage to the macroglial cells and myelin sheaths were also detected in the treated group. All these changes remained in the retina and optic nerve of the oldest rats, as a consequence of the long-lasting effects of prenatal alcohol exposure. In summary, alcohol as a major teratogenic agent may induce dysmorphogenesis and irremediable damage to the retina and optic nerve, which frequently manifests itself as hypoplastic optic nerve.

[Prostaglandins and optic papilla blood flow]

Recent studies found that peripapillary microcirculation was damaged in glaucoma patients, indicating that blood flow in the optic nerve head is important in the pathogenesis of glaucoma. Effects of different antiglaucoma drugs on optic papilla blood flow deserve attention. Prostaglandins is the first line antiglaucoma drug. The experimental and clinical studies on the potential of prostaglandins to modify the blood flow in the optic papilla and related mechanisms are reviewed in this article. Effects of ocular blood flow increase on the treatment of glaucoma require further investigations. (Chin J Ophthalmol, 2017, 53: 73-76).

Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma

Purpose

To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice.

Methods

We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry.

Results

Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP.

Conclusions

The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes in the sclera expressed at the optic nerve head.

Neovibsanin B increases extracellular matrix proteins in optic nerve head cells via activation of Smad signalling pathway

The present study demonstrates the effect of neovibsanin B on the synthesis and deposition of ECM proteins and the signalling pathways used in optic nerve head (ONH) astrocytes and lamina cribrosa (LC) cells. For investigation of the signalling pathway used by neovibsanin B, ONH cells were treated with neovibsanin B. Western blot and immunostaining analyses were used to examine the phosphorylation of proteins involved in Smad and non-Smad signalling pathway. The results revealed that ONH cells on treatment with neovibsanin B showed enhanced synthesis of extracellular matrix (ECM) proteins. Neovibsanin B induced phosphorylation of canonical signalling proteins, Smad2/3. However phosphorylation of non-canonical signalling proteins, extracellular signal-regulated kinases, p38, and c-Jun N-terminal kinases (JNK) 1/2 remained unaffected. There was also increase in co-localization of pSmad2/3 with Co-Smad4 in the nucleus of ONH astrocytes and LC cells indicating activation of the canonical Smad signalling pathway. Treatment of ONH cells with SIS3, inhibitor of Smad3 phosphorylation reversed the neovibsanin B stimulated ECM expression as well as activation of canonical pathway signalling molecules. In addition, inhibition of Smad2 or Smad3 using small interfering RNA (siRNA) also suppressed neovibsanin B stimulated ECM protein synthesis in ONH astrocytes and LC cells. Thus neovibsanin B utilizes the canonical Smad signalling pathway to stimulate ECM synthesis in human ONH cells. The neovibsanin B induced ECM synthesis and activation of the canonical Smad signalling pathway may be due to its effect on transforming growth factor-β2 (TGF-β2). However, further studies are under process to understand the mechanism.

Oral microbiome link to neurodegeneration in glaucoma

BACKGROUND

Glaucoma is a progressive optic nerve degenerative disease that often leads to blindness. Local inflammatory responses are implicated in the pathology of glaucoma. Although inflammatory episodes outside the CNS, such as those due to acute systemic infections, have been linked to central neurodegeneration, they do not appear to be relevant to glaucoma. Based on clinical observations, we hypothesized that chronic subclinical peripheral inflammation contributes to neurodegeneration in glaucoma.

METHODS

Mouthwash specimens from patients with glaucoma and control subjects were analyzed for the amount of bacteria. To determine a possible pathogenic mechanism, low-dose subcutaneous lipopolysaccharide (LPS) was administered in two separate animal models of glaucoma. Glaucomatous neurodegeneration was assessed in the retina and optic nerve two months later. Changes in gene expression of toll-like receptor 4 (TLR4) signaling pathway and complement as well as changes in microglial numbers and morphology were analyzed in the retina and optic nerve. The effect of pharmacologic blockade of TLR4 with naloxone was determined.

FINDINGS

Patients with glaucoma had higher bacterial oral counts compared to control subjects (p<0.017). Low-dose LPS administration in glaucoma animal models resulted in enhancement of axonal degeneration and neuronal loss. Microglial activation in the optic nerve and retina as well as upregulation of TLR4 signaling and complement system were observed. Pharmacologic blockade of TLR4 partially ameliorated the enhanced damage.

CONCLUSIONS

The above findings suggest that the oral microbiome contributes to glaucoma pathophysiology. A plausible mechanism by which increased bacterial loads can lead to neurodegeneration is provided by experiments in animal models of the disease and involves activation of microglia in the retina and optic nerve, mediated through TLR4 signaling and complement upregulation. The finding that commensal bacteria may play a role in the development and/or progression of glaucomatous pathology may also be relevant to other chronic neurodegenerative disorders.

Attenuation of the retinal nerve fibre layer and reduced retinal function assessed by optical coherence tomography and full-field electroretinography in patients exposed to vigabatrin medication

PURPOSE

To investigate the clinical value of assessment of peripapillary retinal nerve fibre layer (RNFL) thickness with OCT in addition to the evaluation of retinal function measured by full-field electroretinography (ff-ERG) in patients with suspected vigabatrin (VGB)-attributed visual field defects.

METHODS

Visual fields from adult patients in our clinical follow-up program for VGB medication were analysed. Twelve patients with suspected VGB-attributed visual field defects were selected for the study. They were re-examined with computerized kinetic perimetry, ff-ERG and OCT (2D circle scan).

RESULTS

Constricted visual fields were found in all patients. Comparative analysis of ff-ERG parameters showed reduced b-wave amplitudes for the isolated and the combined rod and cone responses (p < 0.0001). The a-wave, reflecting photoreceptor activity, was reduced (p = 0.001), as well as the summed amplitude of oscillatory potentials (p = 0.029), corresponding to inner retinal function. OCT measurements demonstrated attenuation of the RNFL in nine of 12 patients, most frequently superiorly and/or inferiorly. No temporal attenuation was found. Significant positive correlations were found between the total averaged RNFL thickness, superior and inferior RNFL thickness and reduced ff-ERG parameters. Positive correlations were also found between RNFL thickness and isopter areas.

CONCLUSION

OCT measurements can detect attenuation of the RNFL in patients exposed to VGB medication. RNFL thickness correlates with reduced ff-ERG parameters and isopter areas of constricted visual fields, indicating that VGB is retino-toxic on several levels, from photoreceptors to ganglion cells. The study also supports previous studies, suggesting that OCT measurement of the RNFL thickness may be of clinical value in monitoring patients on vigabatrin therapy.

[Antioxidant agents in neuroprotection treatment of glaucoma]

Purpose was to study efficiency and safety of mexidol in combined therapy in patients with primary open-angle glaucoma (POAG). 94 patients (185 eyes) at the age of 18-75 years old with POAG I-III stages were divided into 3 groups: 50 patients received combined therapy of mexidol 100 mg and picamilon 150 mg, 22 patients received combined therapy of mexidol 300 mg and picamilon 150 mg, 22 patients received only picamilon 150 mg. All medicine was administered qd during 14 or 21 days. Examination included standard ophthalmologic methods, perimetry, electroretinography, retinal and optic nerve heard arterial blood flow. Improvement of visual acuity, perimetric, electrofisiological indicies and increased blood flow velocity of central retinal artery were registrated. Combined mexidol therapy allows improving results in treatment of patients with POAG.

Increased expression of oxyproteins in the optic nerve head of an in vivo model of optic nerve ischemia

BACKGROUND

To investigate the effects of microvascular compromise on the expression of oxidative proteins in the optic nerve head.

METHODS

Endothelin-1 (0.1 μg/day) was delivered to the perineural region of the anterior optic nerve by osmotically driven minipumps for two, four, and eight weeks in ten rabbits, respectively. As a control, a balanced salt solution was delivered for two and eight weeks in five rabbits, respectively. Expression of oxyproteins in the cornea, vitreous, retina, and optic nerve head for each time period was determined using the OxyBlot protein oxidation detection kit. Retina was stained with H&E and TUNEL for histological examination.

RESULTS

There was a significant increase in the expression of oxyproteins in the optic nerve head after two weeks of endothelin-1 administration (p < 0.001, Mann Whitney U test). In contrast, there was no expression of oxyproteins in the cornea, retina, or vitreous. The number of cells in the retinal ganglion cell layer, inner nuclear layer, and outer nuclear layer decreased remarkably with time in the endothelin-1-treated group. Furthermore, the inner and outer nuclear layers, as well as the inner and outer plexiform layers, became thinner over time.

CONCLUSIONS

Administration of endothelin-1 to the microvasculature of the optic nerve leads to increased expression of oxyproteins in the optic nerve head and loss of retinal ganglion cells.

Retinal nerve fiber layer thickness in patients receiving chronic anti-vascular endothelial growth factor therapy

PURPOSE

To evaluate the effects of multiple intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents on the thickness of the retinal nerve fiber layer (RNFL) in patients with wet age-related macular degeneration (ARMD).

DESIGN

Retrospective, observational, consecutive case series of patients diagnosed with wet ARMD.

METHODS

Forty-one eyes of 37 consecutive patients (25 female and 12 male; mean age 79.2 ± 8.7 years) who underwent treatment with pegaptanib, bevacizumab, and/or ranibizumab for ARMD followed by sequential RNFL thickness measurement by optical coherence tomography (OCT) were studied. Patients were included in the analyses if they had greater than 10 total anti-VEGF injections, RNFL measurements prior to the first injection, and at least 12 months of follow-up. Patients were divided into 3 groups depending on which anti-VEGF agent(s) they received. The OCT RNFL measurements at the initial and final follow-up were used for analyses.

RESULTS

Average follow-up for all patients was 27.0 ± 9.7 months and they received an average of 16.0 ± 5.5 intravitreal injections. The average RNFL thickness at presentation was 92.4 ± 15.2 μm and at last follow-up was 93.8 ± 15.2 μm (P = .68). There were no statistically significant differences in RNFL measurements when comparing between individual anti-VEGF treatment groups.

CONCLUSION

Long-term treatment with anti-VEGF agents did not lead to significant changes in RNFL thickness in a patient population with wet ARMD. Despite the possibility of repeated intraocular pressure (IOP) fluctuations after intravitreal injections and known neurotrophic properties of VEGF in the eye, chronic therapy with intravitreal anti-VEGF agents does not appear to adversely affect RNFL thickness. Further prospective studies with longer follow-up are needed to corroborate the findings of this study.

Sorafenib protects human optic nerve head astrocytes from light-induced overexpression of vascular endothelial growth factor, platelet-derived growth factor, and placenta growth factor

OBJECTIVES

Growth factors, such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and placenta growth factor (PlGF) are key players in the development of diabetic retinopathy, age-related macular degeneration, and other retinal neovascular diseases. Glial cells provide a significant source of retinal growth factor production under physiologic and pathologic conditions. Cumulative light exposure has been linked to increased retinal growth factor expression. Previous reports indicate that sorafenib, an oral multikinase inhibitor, might have a beneficial effect on retinal neovascularization. This study was designed to investigate the effects of sorafenib on light-induced overexpression of growth factors in human retinal glial cells.

METHODS

Primary human optic nerve head astrocytes (ONHAs) were exposed to white light and incubated with sorafenib. Viability, expression, and secretion of VEGF-A, PDGF-BB, and PlGF and their mRNA were determined by reverse transcription-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay.

RESULTS

Light exposure decreased cell viability and increased VEGF-A, PDGF-BB, and PlGF expression and secretion. These light-induced effects were significantly reduced when cells were treated with sorafenib at a concentration of 1 microg/ml.

CONCLUSION

Sorafenib significantly reduced light-induced overexpression of VEGF-A, PDGF-BB, and PlGF in primary human ONHAs. Sorafenib has promising properties as a potential supportive treatment for retinal neovascularization.

Reversal of optic disc cupping with improvement of visual field and stereometric parameters after trabeculectomy in young adult patients (two case reports)

The authors report two cases of mid- to long-term reversal of optic disc cupping after trabeculectomy with mitomycine-C in young adult patients suffering from secondary glaucoma. The cup to disc ratio reversed from 0.80 and 0.60 to 0.65 and 0.40 respectively and remained unchanged until the last follow-up visit at 6 and 36 months respectively. Concomitantly, there was an improvement of the visual field and of the optic disc stereometric parameters on the Heidelberg Retina Tomograph.

Ocular toxicity of intravitreal trovafloxacin in the pigmented rabbit

PURPOSE

Trovafloxacin is an expanded spectrum, newer-generation fluoroquinolone antibiotic with improved Gram-positive and anaerobic activity compared with existing quinolones, while maintaining Gram-negative activity comparable to ciprofloxacin. Given its broad spectrum of activity, trovafloxacin may have potential use for treatment of acute bacterial endophthalmitis. This study examined the toxicity of intravitreally administered trovafloxacin in the pigmented rabbit eye.

METHODS

Doses of trovafloxacin ranging from 12.5 microg to 1000 microg were injected into the mid-vitreous of Dutch Belted rabbit eyes. Clinical examination was performed at 1, 3, and 14 days following injection. Animals were sacrificed and eyes were enucleated 14 days following injection. Light microscopy (LM) and transmission electron microscopy (TEM) studies of the optic nerve head, medullary ray, and inferior retina were performed to determine toxicity.

RESULTS

At intravitreal doses of 500 microg and less, no toxicity was observed at the ophthalmoscopic or light microscopic level. By TEM, a dose-dependent increase in injury to retinal pigment epithelium, photoreceptors, and nerve fibers in the optic nerve head and medullary ray was observed from 50 microg to 500 microg. No toxicity was noted at doses of 12.5 microg and 25 microg. At doses of 750 microg and above, edema of the medullary ray was noted on ophthalmoscopy. Swelling of the peripapillary medullary ray and necrosis of the inferior retina were evident on LM.

CONCLUSION

Intravitreal trovafloxacin doses of 50 microg and higher in the pigmented rabbit eye cause retinal and nerve fiber injury. Intravitreal doses 25 microg and lower appear to be safe, with no evidence of ocular toxicity.

Decrease of optic disc cupping and pallor of ocular hypertensives with timolol therapy

PURPOSE

The purpose of this study was to determine whether timolol drops compared to placebo drops had a significant effect on optic disc cupping and pallor in ocular hypertensives.

METHODS

Thirty-seven ocular hypertensives were randomly assigned to placebo or 0.5% timolol drops to both eyes in a double masked clinical trial. Measurements of ocular pressure and photographs of the optic disc for cupping by photogrammetry and pallor by computerized image analysis were made at about 3 month intervals, for 18 to 24 months of follow-up.

RESULTS

None of the subjects developed visual field loss when tested with the Goldmann perimeter by kinetic and static means at six month intervals. Subjects treated with timolol developed a significant decrease in ocular pressure and a significant decrease in optic disc cupping with a smaller decrease in pallor compared to subject treated with placebo. Multivariate analyses indicated that the decrease of optic disc cupping and pallor was not associated with the ocular pressure on treatment or the decrease in ocular pressure during the trial.

CONCLUSION

Timolol treatment was associated with a decrease in optic disc cupping and pallor. The effect of timolol appears to be related to mechanisms other than the decrease in ocular pressure.

Efficacy, tolerability and safety of the fixed combination of bimatoprost 0.03% and timolol 0.5% in a broad patient population: multicenter, open-label observational study

OBJECTIVE

To evaluate intraocular pressure (IOP)-lowering efficacy, tolerability, and safety of the fixed combination of bimatoprost 0.03% and timolol 0.5% (Ganfort) among German patients.

METHODS

Multicenter, observational, open-label study of patients with primary open angle glaucoma or ocular hypertension (n = 606). As determined by participating physicians, patients had insufficient IOP control and required a medication change. They were switched to once-daily fixed-combination bimatoprost/timolol with no wash-out period. IOP was recorded at treated baseline, 4-6 weeks and 12 weeks after switching. Tolerability was measured using a 4-step scale (excellent, good, moderate, poor) and all adverse events were recorded.

RESULTS

A total of 405 patients switched from monotherapy, 97 switched from other fixed combinations, and 104 switched from non-fixed combinations. Among all patients, 32.5% had used prostaglandin analog (PGA) monotherapy, 8.7% had been using a fixed combination that included a PGA, and 6.9% had been using an adjunctive combination of a PGA and a beta-blocker. Mean treated baseline IOP (+/-SD) for all patients was 20.7 +/- 3.5 mmHg. Overall, changing medication to fixed-combination bimatoprost/timolol lowered IOP to 16.6 +/- 2.7 mmHg (p < 0.001 vs. baseline) after 4-6 weeks and to 16.1 +/- 2.6 mmHg (p < 0.001) after 12 weeks; reductions of 19.8% and 22.2%, respectively. Combined bimatoprost/timolol provided an additional IOP reduction versus baseline in most subgroups based on prior treatment. At week 12, patients who had previously used a beta-blocker achieved an additional 25.8% decrease from baseline and IOP was reduced by 22.6% in former PGA monotherapy patients. At week 12, 84.6% of all eyes reached a target pressure less than or equal to 18 mmHg. Tolerability of bimatoprost/timolol was rated excellent or good by the physicians for 98.7% of patients and by 96.7% of the patients themselves. Few adverse events occurred during the treatment period.

CONCLUSIONS

Although this study was limited by its observational design, our results show that the fixed combination of bimatoprost 0.03%/timolol 0.5% was effective, well tolerated, and safe in a broad patient population.

Emerging syphilitic optic neuropathy: critical review and recommendations

BACKGROUND

Infection with Treponema pallidum causes multiorgan manifestations including isolated optic nerve involvement at any stage of the disease. This is of particular interest for resulting in severe visual impairment, which is reversible if treated adequately.

PURPOSE

To review clinical and diagnostic findings in patients with optic nerve affection in neurosyphilis and to focus on the visual outcome after administering adjunctive cortisone to the standard therapy regimes with penicillin G.

METHODS/PATIENTS

The review is based on a retrospective case serial of 4 patients (three males: mean age 40 years, range 37-42 years; one female: mean age 62 years) with optic nerve involvement in neurosyphilis treated in our hospital, and on a literature review of recent publications. Patients were treated with systemic penicillin either with or without adjunctive cortisone. The major outcome measure of therapy was improvement of visual acuity.

RESULTS

Visual outcome in our case serial showed total restoration if cortisone was also administered. The bibliographic survey, which was based on 60 patients, also revealed a better improvement of vision when antibiotic medication was combined with cortisone.

CONCLUSIONS

The data show that the causal therapy of choice is undoubtedly penicillin G, with adjunctive steroids playing a crucial role in improvement of optic nerve functional outcome. Physicians should consider the use of cortisone in SON whenever clinically harmless, although prospective randomized multicenter studies are required to support this recommendation.

Effect of statin drugs and aspirin on progression in open-angle glaucoma suspects using confocal scanning laser ophthalmoscopy

PURPOSE

To determine the effect of statins and aspirin on the rate of progression of optic nerve parameters in open-angle glaucoma (OAG) suspects, as defined by confocal scanning laser ophthalmoscopy (CSLO).

METHODS

Data of OAG suspects who had undergone at least two CSLO tests at the Beckman Vision Center at UCSF from January 2001 to June 2006 was collected. We conducted a retrospective chart review of 149 eyes from 76 patients considered suspect for glaucoma based on a cup-to-disc ratio >0.5, but with normal intraocular pressures (IOP) and visual fields. Subjects included glaucoma suspects who took statin drugs or aspirin for greater than 23 months. The control group consisted of suspects who never used statins or aspirin. The data were analysed using mixed effects regression.

RESULTS

When comparing controls with the statin group there were significant differences in the progression of multiple CSLO parameters per year, including rim volume (-13.7% controls, +26.7% statin only; P = 0.0156), retinal nerve fibre layer cross-sectional area (-12.2% controls, +24.3% statin only; P = 0.0051), and mean global retinal nerve fibre layer thickness (-10.3% controls, +26.6% statin only; P = 0.0114), with adjustment for age, gender, race, IOP, central corneal thickness, refractive error and multiple systemic comorbidities. No significant differences were found when comparing subjects taking a statin plus aspirin or aspirin alone with the controls.

CONCLUSIONS

Statin drugs may be associated with slowed progression of optic nerve parameters in glaucoma suspects as measured by CSLO.

Intravitreal Triamcinolone Improves Recovery of Visual Acuity in Nonarteritic Anterior Ischemic Optic Neuropathy

BACKGROUND

The visual outcome in untreated nonarteritic anterior ischemic optic neuropathy (NAION) is dismal. Because intravitreal triamcinolone (IVTA) has shown promise in improving edematous retinal disorders, a pilot trial of this therapy in NAION was considered reasonable.

METHODS

Four eyes of 4 patients with severe visual loss due to NAION were treated with 4 mg IVTA (study group). The control group consisted of 6 consecutive patients with NAION who received no treatment. Patients were evaluated by the visual acuity and visual field measurements of the Early Treatment Diabetic Retinopathy Study (ETDRS) and fluorescein angiography.

RESULTS

All patients completed at least 9 months of follow-up. In the study group, the mean improvement in visual acuity were 4, 5.8, and 6.2 ETDRS lines at the first and third weeks and final visit, respectively. Optic disc swelling and leakage had markedly decreased at the first postinjection week and had disappeared by the third week examination in all eyes. In the control group, the mean improvements in visual acuity were 0, 0.7, and 1.3 ETDRS lines at the first and third weeks and final visit, respectively. Control eyes showed resolution of the optic disc swelling between the fourth week and third month visits. No marked change in visual field defects was observed in either group.

CONCLUSIONS

IVTA provided relatively improved recovery of visual acuity and relatively rapid resolution of optic disc swelling in a small sample of patients with acute NAION. It did not provide visual field improvement. A larger trial is merited by the results of this small pilot study.

Differential effects of tamoxifen and anastrozole on optic cup size in breast cancer survivors

Introduction

The main purpose of this study was to determine whether the optic cups of tamoxifen users and anastrozole users differ in size, with the cups of the tamoxifen users being smaller.

Methods

Optic nerve head (ONH) topography was measured using a commercially available, confocal scanning laser ophthalmoscope for three populations of amenorrheic women ages 40–69 years: subjects using (1) tamoxifen (20 mg/day) or (2) anastrozole (1 mg/day) for ≤ 2 years as adjuvant therapy after successful primary treatment for breast cancer, and (3) control subjects with no breast cancer histories and not using any hormonal medication. All subjects had excellent visual acuity and healthy eyes, based on conventional photographic assessment.

Results

The cup volumes of the tamoxifen users were shown to be significantly smaller than the cup volumes of the anastrozole users, which were indistinguishable from normal. Because the cup volumes of the tamoxifen users decreased markedly with age at about 50 years and because anastrozole is indicated only for post-menopausal women, comparisons were reassessed for subjects older than 50 years. For these subjects, the cup volumes of the tamoxifen users averaged less than half of the volumes for each of the other two subject groups, and significant between-group differences existed in both the lateral (cup area) and axial (cup depth) directions. In contrast, any between-group differences at the ONH margin were small and not significant.

Conclusions

The results of this study suggest that the ONH be assessed biomorphometrically for tamoxifen users reporting visual change that cannot be attributed to non-tamoxifen causes. The ability of modern intraocular imaging techniques to reveal anatomic change on the order of tens of microns may be useful for assessing tamoxifen-induced effects occurring simultaneously elsewhere in the brain, particularly since the presence of small cups is consistent with the possibility of tamoxifen-induced astrocytic swelling.

[The influence of intraocular pressure reduction with medication on retinal nerve fiber layer thickness measurements obtained with scanning laser polarimetry in glaucomatous and hypertensive eyes]

PURPOSE

To evaluate changes in retinal nerve fiber layer thickness as measured by scanning laser polarimetry (SLP) after the use of medication to reduce intraocular pressure (IOP) in glaucomatous or ocular hypertensive patients.

METHODS

The authors prospectively enrolled 37 eyes of 37 patients in whom IOP was reduced by more than 25% after the use of medication. The images were obtained before and 15 to 30 days after the introduction of medication. The SLP parameters measured before and after the use of medication were compared using paired Student's t Test.

RESULTS

The mean IOP was significantly reduced from 26.57 +/- 4.23 mmHg to 16.54 +/- 2.92 mmHg after the use of medication (p < 0.05). None of the 10 SLP analyzed parameters was significantly affected by the reduction of IOP with medication (p > 0.05).

CONCLUSION

The retinal nerve fiber layer thickness, as measured by SLP, is not affected by the reduction of IOP with medication in patients with glaucoma or ocular hypertension.

Intravitreal injection of endothelin-1 caused optic nerve damage following to ocular hypoperfusion in rabbits

The purpose of this study was to investigate the time course of the ocular hypoperfusion, retinal damage, and optic nerve damage induced by intravitreal injection of endothelin-1 (ET-1) in rabbits. ET-1, at 5 pmol (20 microL, twice a week for 2 or 4 weeks), was injected from the pars plana into the posterior vitreous of the right eye. Optic nerve head (ONH) blood flow and retinal artery diameter, together with the neurofilament light chain (NF-L) content, retinal morphology, and axon density of the optic nerve, were evaluated at 2, 4, and 8 weeks after the first injection of ET-1 (n=7 or 8). Tissue blood velocity in ONH was measured using a laser speckle method, and the diameter of major retinal arteries on the rim of the ONH was calculated from fundus photographs by a masked observer. Histological analysis and immunoblot evaluation of NF-L in the optic nerve were performed to evaluate optic nerve damage. At 2 weeks after the first ET-1 injection, tissue blood velocity was decreased by approximately 20% (versus the contralateral eye), and the diameter of retinal arteries had decreased by approximately 40%. These changes were sustained at the same level until 8 weeks after the first ET-1 injection. At 4 and 8 weeks after the first ET-1 injection, the amount of NF-L in the optic nerve was significantly less in the ET-1 treated eyes than in the contralateral eyes. At 8 weeks after the first ET-1 injection, a loss of myelinated axons and increases in gliosis and connective tissue were noted in the optic nerve of the treated eye, and the optic nerve-axon number had decreased significantly (each, versus the untreated eye). Retinal ganglion cells in the retina were not observed any damage at 2, 4, and 8 weeks after ET-1 injection. In conclusion, intravitreal injection of ET-1 induced chronic hypoperfusion in the ONH and retina, which presumably caused decreases in NF-L content and axon number in the optic nerve noted in the later part of the observation period.

Triamcinolone Acetonide–Induced Ocular Hypertension

PURPOSE

The aim of this study is to report on the clinical course of a patient showing markedly increased intraocular pressure (IOP) caused by intravitreal triamcinolone acetonide.

METHODS

A 33-year-old patient received an intravitreal injection of approximately 20 mg of triamcinolone acetonide (TA) as treatment of otherwise therapy-resistant uveitis. She experienced an IOP rise to values over 40 mmHg for a period for more than 3 months, despite maximal antiglaucomatous medical therapy. Peak IOP was 55 mmHg.

RESULTS

Neither confocal scanning laser tomography nor qualitative assessment of optic disc photographs nor perimetry showed development of glaucomatous changes. Scanning laser polarimetry of the retinal nerve fiber layer suggested a slight loss in the nasal upper fundus quadrant.

CONCLUSIONS

Relatively young patients with a pronounced TA-induced rise in IOP, unresponsive to maximal antiglaucomatous medication, may not necessarily undergo antiglaucomatous surgery if the rise in IOP does not last longer than approximately 3 months.

Small optic cup sizes among women using tamoxifen: assessment with scanning laser ophthalmoscopy

PURPOSE

There is a substantial literature showing that the selective estrogen receptor modulator tamoxifen can block swelling-activated chloride channels, such as those in astrocytes. This study aimed to test the hypothesis that anatomic characteristics consistent with swelling may be measured within the optic nerve head (ONH) of tamoxifen users whose ONH appearance is considered within normal limits.

METHODS

Indices of ONH topography were measured using the Heidelberg Retina Tomograph II (HRT) for two populations of women ages 40-69 years: (1) subjects using tamoxifen (20 mg/day) as adjuvant therapy after successful primary treatment for breast cancer and (2) control subjects not using any hormonal medication. All subjects had excellent visual acuity (with 20/20 or better in the test eye), and all appeared to be free of eye disease, as based on conventional photographic assessment. The study design was cross-sectional. The various ONH indices were assessed as functions of the duration of tamoxifen use.

RESULTS

The optic cups of short-term tamoxifen users (<or=2 years) were significantly smaller in both the lateral and axial directions than the optic cups of the control subjects. Of the 27 short-term users, 23 had cup volumes smaller than the median value for the control subjects. The cup sizes of long-term users (> 2 years, <or=5 years) were not distinguishable from those of the control subjects. The presence of small cups among short-term users did not depend on subjects' medical histories prior to tamoxifen use. Disk margin indices were not related significantly to the duration of tamoxifen use.

CONCLUSIONS

Small cup sizes consistent with localized subclinical swelling are not rare among short-term tamoxifen users. Thus, small cups are not likely to be a manifestation of a cumulative-dose toxicity. Instead, they probably result from other causes, possibly involving the action of tamoxifen on estrogen receptors. Further investigation with longitudinal and interventional methodologies is needed to definitively interpret the results.

Leber's Hereditary Optic Neuropathy Precipitated by Ethambutol

BACKGROUND

Leber's hereditary optic neuropathy (LHON) predominantly affects young men between 10 and 30 years of age. However, two cases of LHON during ethambutol administration have been reported in older men and one case in an older woman. We now report a second case of an older woman in whom administration of ethambutol triggered the development of LHON.

CASE

A 70-year-old woman received ethambutol, rifampicin, isoniazid, and pyrazinamide for the treatment of tuberculosis.

OBSERVATIONS

Three months after the beginning of this treatment, a marked decrease in visual acuity occurred in both eyes and ethambutol was discontinued. Her corrected visual acuity was 0.03 in both eyes. There was no hyperemia, swelling of the optic disc, or capillary dilatation in either eye. Centrocecal scotomas were found bilaterally. After 1 month, her visual acuity had further decreased to 0.01, and the scotomas had enlarged. At this time, genetic analysis revealed a point mutation in mitochondrial DNA 11778.

CONCLUSIONS

Ethambutol can be a risk factor for LHON because the number of reported ethambutol-related LHON cases has increased to four, including the present one. Ethambutol administration to patients with a family history of LHON should be avoided.

Endothelin-1 Impairs Retrograde Axonal Transport and Leads to Axonal Injury in Rat Optic Nerve

The purpose of this study was to examine the effects of endothelin-1 (ET-1) on retrograde axonal transport in the rat optic nerve. Vehicle or ET-1 (0.2, 1, or 5 pmol/eye) were injected into the vitreous body in Sprague-Dawley rats. Retinal vessels were observed, using a fundus camera, before, and at 10 min, 3 days and 7 days after a single intravitreous injection. Two days after the injection, a neuronal tracer, fluoro gold, was administered via the superior colliculi to retrogradely label active retinal ganglion cells (RGCs). Five days after the tracer administration, retrogradely labeled RGCs were evaluated in the flat-mounted retina, and cross sections from each optic nerve were graded for injury by four independent, masked observers. ET-1 at 5 pmol/eye caused a significant constriction of retinal vessels (versus the vehicle-treated group) at 10 min after the injection. Intravitreous injection of ET-1 caused a dose-related decrease in the number of retrogradely labeled RGCs. Injection of 5 pmol/eye ET-1 led to a statistically significant decrease in the number of retrogradely labeled RGCs (versus the vehicle-treated group). ET-1 at 1 and 5 pmol/eye caused histological optic nerve damage (evaluated using a graded scale). The histological optic nerve damage correlated with the number of retrogradely labeled RGCs. In conclusion, a single intravitreous injection of ET-1 impaired retrograde axonal transport in the rat optic nerve and this impairment correlated with the histological optic nerve damage.

Photodynamic therapy in the management of juxtapapillary capillary haemangiomas

Capillary haemangiomas occurring on or adjacent to the optic disc pose unique therapeutic problems. Their natural history is highly variable, but has a propensity to lead to the development of progressive exudate with marked deterioration in visual acuity, often culminating in retinal detachment and vitreal haemorrhages. On reviewing the literature, no therapeutic modality has demonstrated an efficacy in treating the lesion and providing an acceptable visual acuity result. A case of a 61-year-old man with a left-sided juxtapapillary capillary haemangioma treated with verteporfin photodynamic therapy is described. The patient's visual acuity improved from 6/36 to 6/12 initially, with an appreciable reduction in exudate and lesion size. Subsequent treatments failed to eradicate the lesion, with visual acuity stabilizing at 6/60. With larger cohorts of patients and variable treatment parameters, the true efficacy of photodynamic therapy to treat these lesions may be determined.

Transforming growth factor-beta-regulated gene transcription and protein expression in human GFAP-negative lamina cribrosa cells

Primary open-angle glaucoma (POAG) is a progressive optic neuropathy, which is a major cause of worldwide visual impairment and blindness. Pathological hallmarks of the glaucomatous optic nerve head (ONH) include retinal ganglion cell axon loss and extracellular matrix (ECM) remodeling of the lamina cribrosa layer. Transforming growth factor-beta (TGF-beta) is an important pro-fibrotic modulator of ECM metabolism, whose levels are elevated in human POAG lamina cribrosa tissue compared with non-glaucomatous controls. We hypothesize that in POAG, lamina cribrosa (LC) glial cells respond to elevated TGF-beta, producing a remodeled ONH ECM. Using Affymetrix microarrays, we report the first study examining the effect of TGF-beta1 on global gene expression profiles in glial fibrillary acidic acid (GFAP)-negative LC glial cells in vitro. Prominent among the differentially expressed genes were those with established fibrogenic potential, including CTGF, collagen I, elastin, thrombospondin, decorin, biglycan, and fibromodulin. Independent TaqMan and Sybr Green quantitative PCR analysis significantly validated genes involved in regulation of cell proliferation (platelet-derived growth factor [PDGF-alpha]), angiogenesis (vascular endothelial growth factor [VEGF]), ECM accumulation and degradation (CTGF, IL-11, and ADAMT-S5), and growth factor binding (ESM-1). Bioinformatic analysis of the ESM-1 promoter identified putative Smad and Runx transcription factor binding sites, and luciferase assays confirmed that TGF-beta1 drives transcription of the ESM-1 gene. TGF-beta1 induces expression and release of ECM components in LC cells, which may be important in regulating matrix remodeling in the lamina cribrosa. In disease states such as POAG, the LC cell may represent an important pro-fibrotic cell type and an attractive target for novel therapeutic strategies.

The influence of various substances on the biomechanical behavior of lamina cribrosa and peripapillary sclera

PURPOSE

Changes in the biomechanical properties of the lamina cribrosa (LC) and of the peripapillary sclera (ppSc) may play a role in the pathogenesis of glaucoma. The purpose of this study was to assess the influence of glyceraldehyde, methylglyoxal, and collagenase A on the mechanical properties of the LC and ppSc.

METHODS

Two strips of 1-mm width were cut from each of 80 porcine eyes and 24 pairs of enucleated human eyes. One strip contained the LC and the other the adjacent superior ppSc. One half of the strips was divided into groups and treated with 0.5 M glyceraldehyde, 0.5 M methylglyoxal, and 0.1% collagenase A. The other strips served as the control. The stress strain relation was measured in the stress range of 0.02 to 6.0 MPa by a biomaterial tester.

RESULTS

Stress values at 20% strain of the human LC changed from 1.97 +/- 1.48 to 3.40 +/- 1.60 MPa after incubation with glyceraldehyde (P = 0.029), from 2.42 +/- 2.22 to 5.46 +/- 1.91 MPa (P = 0.014) after incubation with methylglyoxal, and from 2.43 +/- 1.3 to 1.35 +/- 0.19 MPa after incubation with collagenase A. The stress values of human ppSc without glyceraldehyde were 3.40 +/- 2.59 and 7.45 +/- 4.46 MPa after incubation with glyceraldehyde (P = 0.047), 4.80 +/- 3.05 MPa without methylglyoxal and 16.10 +/- 5.53 MPa (P = 0.001) after incubation with methylglyoxal, 4.14 +/- 2.56 MPa without collagenase A, and 1.97 +/- 0.55 MPa after incubation with collagenase A. At a 20% strain, Young's moduli of the untreated LC were in the range of E = 11.8 to 15.6 MPa and E = 28.5 to 36.0 MPa of the untreated ppSc.

CONCLUSIONS

Glyceraldehyde and methylglyoxal increase the stiffness of the LC and of the ppSc in human and in porcine eyes. These substances induce changes in the extracellular matrix according to the Maillard reaction as it occurs during the ageing process or in case of high blood glucose levels. Collagenase reduces the stiffness of the tissues.

Optic nerve and neuroprotection strategies

BACKGROUND

Experimental studies have yielded a wealth of information related to the mechanism of ganglion cell death following injury either to the myelinated ganglion cell axon or to the ganglion cell body. However, no suitable animal models exist where injury can be directed to the optic nerve head region, particularly the unmyelinated ganglion cell axons. The process of relating the data from the various animal models to many different types of optic neuropathies in man must, therefore, be cautious.

RESULTS

Extensive studies on the isolated optic nerve have yielded valuable information on the way white matter is affected by ischaemia and how certain types of compounds can attenuate the process. Moreover, there are now persuasive data on how ganglion cell survival is affected when the ocular blood flow is reduced in various animal models. As a consequence, the molecular mechanisms involved in ganglion cell death are fairly well understood and various pharmacological agents have been shown to blunt the process when delivered before or shortly after the insult.

CONCLUSIONS

A battery of agents now exist that can blunt animal ganglion cell death irrespective of whether the insult was to the ganglion cell body or the myelinated axon. Whether this information can be applied for use in patients remains a matter of debate, and major obstacles need to be overcome before the laboratory studies may be applied clinically. These include the delivery of the pharmacological agents to the site of ganglion cell injury and side effects to the patients. Moreover, it is necessary to establish whether effective neuroprotection is only possible when the drug is administered at a defined time after injury to the ganglion cells. This information is essential in order to pursue the idea that a neuroprotective strategy can be applied to a disease like glaucoma, where ganglion cell death appears to occur at different times during the lifetime of the patient.

[Choroidal neovascularization followed in a patient with "Multiple Evanescent White Dot Syndrome" (MEWDS) -- a case report]

BACKGROUND

Since the description of the "multiple evanescent white dot syndrome" (MEWDS) by Jampol et al, choroiditis has been in the focus of interest. But the classical type of MEWDS was an exceptional case in clinical routine.

CASE REPORT

A 48-year-old female presented to our hospital with a sudden unilateral visual acuity decrease and an extension of the blind spot. Ophthalmoscopy and fluorescein angiography revealed typical multiple grey-white chorioretinal patches of the same stage with lesion areas of about 100 - 200 microm compatible with the diagnose of MEWDS. Although visual acuity increased continuously the patient developed a classical choroidal neovascularization within 4 weeks. She was treated with PDT and visual acuity as well as the ophthalmoscopic diagnosis remained stable.

CONCLUSION

In spite of visual improvement in MEWDS, regular control is recommended. In addition we propose to consider the diagnosis of MEWDS if an enlargement of the blind spot and CNV without lesions of the retinal pigment epithelium are diagnosed.

Transforming growth factor-beta 2 modulated extracellular matrix component expression in cultured human optic nerve head astrocytes

PURPOSE

To study whether glaucomatous extracellular matrix (ECM) modifications in the lamina cribrosa might be induced by TGF-beta 2, the effect of TGF-beta 2 on the expression of collagen types I (Col1 alpha 1), III (Col3 alpha 1), and IV (Col4 alpha 2); fibronectin (FN); tissue transglutaminase (TGM2); connective tissue growth factor (CTGF); and thrombospondin (TSP-1) in cultured human optic nerve head (ONH) astrocytes was investigated.

METHODS

Astrocytes were isolated from eyes of five human donors, and cultured monolayers were treated with 1.0 ng/mL TGF-beta 2 for 24 and 48 hours. Expression of Col1 alpha 1, Col3 alpha 1, Col4 alpha 2, FN, TGM2, CTGF, and TSP-1 was examined by semiquantitative RT-PCR and Northern and Western blot analyses. The effect of CTGF silencing on the TGF-beta 2-modulated expression of these genes was investigated by transfection of CTGF small interfering (si)RNA before TGF-beta 2 treatment.

RESULTS

TGF-beta 2 treatment upregulated the expression of Col1 alpha 1, Col4 alpha 2, FN, CTGF, TGM2, and TSP-1 mRNA and protein in cultured astrocytes. Inductions ranged between 1.5- and 4-fold. Expression of Col3 alpha 1 remained unaffected. Transfection of 10 nM CTGF siRNA inhibited the TGF-beta 2-induced upregulation of CTGF, Col4 alpha 2, Col1 alpha 1, TGM2, and FN, whereas TSP-1 expression was not reduced.

CONCLUSIONS

TGF-beta 2 is capable of inducing the expression of ECM and basement membrane components in cultured ONH astrocytes via CTGF and upregulated TSP-1, a protein naturally involved in the activation of latent TGF-beta. Therefore, TGF-beta 2 could be a factor in the initiation of the modification of ECM in the glaucomatous ONH. In addition, TSP-1 induction may be a mechanism by which TGF-beta 2 amplifies its own activation.

Papilledema and abducens nerve palsy following ethylene glycol ingestion

A 34-year-old male with a long-standing history of polysubstance abuse and depression was admitted for acute renal failure and hemodialysis secondary to ethylene glycol ingestion that occurred two days prior. The patient was admitted with documented ethylene glycol levels of 41.2 mg/dl, which fell to 25.0 mg/dl after 8 hours and to 6 mg/dl after 12 hours. One week later the patient presented to the outpatient eye clinic complaining of headaches and diplopia. On exam, vision in both eyes was 20/20. No afferent papillary defect was present. The patient had a left abducens palsy. The remainder of the anterior segment exam was normal. On dilated fundus exam the patient was found to have 3+ disc edema with hemorrhages in both eyes. A lumbar puncture revealed elevated intracranial pressure. In our opinion, the patient developed a left abducens nerve palsy and bilateral disc edema secondary to a transient rise in intracranial pressure after ingestion of ethylene glycol.

[Irrigation therapy as a method of intensive care of ophthalmopathology in the posterior eye segment in children]

Presented in the paper are data of a comparative analysis of efficiency of different methods of administration of drugs in neuritis and partial atrophy of the optic nerve. New techniques of application and fixation of irrigation systems in the retrobulbar and Tenon's space are described. Experimental and clinical data proving advantages of the new method of administration of drugs by an automatic pulse doser in the treatment of inflammatory diseases of the optic nerve are represented. The use of such intensive intermittent technique of administration of drugs in Tenon's space performed at the preliminary stage before electrostimulation of the optic nerve made the procedure by far more effective and ensured better treatment results.

The clinical spectrum of amiodarone-associated optic neuropathy

PURPOSE

To describe the clinical spectrum of amiodarone-associated optic neuropathy.

METHODS

Observational cases series and review.

RESULTS

Of 55 cases, the median interval for onset of optic neuropathy was four months after initiating amiodarone; 88% occurred within 12 months. Seven (13%) patients were asymptomatic. Twenty-two (40%) patients presented with sudden visual loss, while 26 (47%) had insidious loss of vision. Visual acuity ranged from 20/15 to light perception; 10 (18%) patients had legal blindness with visual acuity of 20/200 or worse. Visual field loss was present in 91% of cases. Color vision loss was present in eight (40%) of 20 cases. Optic disc edema was present in 85% of cases, while eight (15%) patients had retrobulbar optic neuropathy, without evidence of disc edema. Optic disc edema resolved over a median time of three months. Five patients had raised intracranial pressure on lumbar puncture.

CONCLUSION

We were able to classify amiodarone-associated optic neuropathy into five clinical categories with respect to temporal characteristics and optic nerve appearance: insidious-onset (43%), acute-onset (28%), retrobulbar (13%), increased intracranial pressure (8%), and delayed-progressive onset (8%). Most cases of optic neuropathy commenced within 12 months of initiating amiodarone, with the median onset being four months. Over 10% of patients will have no visual symptoms at the onset. Ophthalmologic examinations within the first 12 months--and particularly within four months of initiating amiodarone--should improve early detection of amiodarone-associated optic neuropathy.

[Retinal ICG-accumulation after ILM-staining during macular hole surgery?]

BACKGROUND

In earlier animal studies retinal accumulation of ICG after intravitreous application with subsequent transport to the optic nerve could be observed. In order to evaluate the possible retinal accumulation of ICG after ILM staining during macular hole surgery and to examine the potential changes in optic nerve function, a prospective study was initiated.

METHODS

In 20 patients with macular holes grade 3, vitrectomy with ICG staining of the ILM (0.3 ml of a 1:10 diluted ICG solution under air), consecutive ILM peeling, and finally gas tamponade were performed. Preoperatively and 2, 4, 8, 12, and 24 weeks after vitrectomy, all patients underwent normal ophthalmological examination, native ICG picture, VEP examinations, and central visual field examination.

RESULTS

Retinal ICG accumulation in the area of the macular hole, in the retinal axons at the temporal arcades, and around the optic disc could be observed in all 20 patients. This staining with ICG was progressively transformed towards the optic disc at the 4- and 8-week examinations. At the 12-week examination, ICG staining around the optic disc was still visible in all patients. The function of the optic nerve (VEP) demonstrated only minor changes during follow-up, and in the visual field examinations no peripheral changes could be observed.

CONCLUSIONS

After ILM staining with ICG during macular hole surgery even with highly diluted ICG solutions an accumulation of ICG in the retinal ganglion axons was observed. This accumulation was visible shortly after surgery at the macular hole, temporal arcades, and the optic disc. The predominant staining of ICG at the optic disc during follow-up can be interpreted as transport of the accumulated ICG in the retinal axons and optic nerve. There seem to be no functional implications for optic nerve function and visual field examinations.

Effect of Cyclical Mechanical Stretch and Exogenous Transforming Growth Factor-??1 on Matrix Metalloproteinase-2 Activity in Lamina Cribrosa Cells from the Human Optic Nerve Head

PURPOSE

Extensive remodeling of the lamina cribrosa extracellular matrix occurs in primary open angle glaucoma. The transforming growth factor-beta (TGF-beta) and matrix metalloproteinase (MMP) protein families are implicated in this process. The authors investigated (a). the effect of cyclical mechanical stretch on TGF-beta1 mRNA synthesis, TGF-beta1 protein secretion, MMP-2 protein activity and (b). the effect of exogenous TGF-beta1 on MMP-2 protein activity in human lamina cribrosa cells in vitro.

METHODS

Primary human lamina cribrosa cells grown on flexible and rigid plates were exposed to cyclical stretch (1Hz, 15%) or static conditions for 12 and 24 hours. Cells grown on 100-mm plates were exposed to human TGF-beta1 (10 ng/ml) or vehicle (4 mM HCl/1% BSA) for 24 hours. TGF-beta1 mRNA synthesis in stretched and static cells was measured using real-time polymerase chain reaction. TGF-beta1 protein secretion in stretched and static cell media was measured using enzyme linked immunosorbent assay. Gelatin zymography measured MMP-2 activity in stretched, static, TGF-beta1- treated and vehicle-treated cell media.

RESULTS

Cyclical stretch induced significant increases in TGF-beta1 mRNA synthesis after 12 hours (**P < 0.01) and TGF-beta1 protein secretion after 24 hours (*P < 0.05). Cyclical stretch significantly (*P < 0.05) increased MMP-2 activity in cell media after 24 hours. Exogenous TGF-beta 1 induced a significant (**P < 0.01) increase in cell media MMP-2 activity after 24 hours.

CONCLUSIONS

These results suggest that cyclical stretch and TGF-beta1 modulate MMP-2 activity in human lamina cribrosa cells. TGF-beta 1 and MMP-2 release from lamina cribrosa cells may facilitate matrix remodeling of the optic nerve head in primary open angle glaucoma.

Hypoxia augments TNF-alpha-mediated endothelin-1 release and cell proliferation in human optic nerve head astrocytes

The effect of hypoxia (24 h) on TNF-alpha-mediated release of endothelin-1 (ET-1) from human optic nerve head astrocytes (hONAs) and TNF-alpha- and ET-1-induced hONA proliferation was determined. ET-1 synthesis and release was quantitated using ELISA while TNF-alpha (10 nM)- and ET-1 (100 nM)-mediated hONA proliferation was assessed by CellTiter 96 aqueous one-solution cell proliferation assay, respectively. hONAs appeared to be more rounded with fewer processes following 24 h hypoxia compared to thodr seen in normoxia. Hypoxia enhanced TNF-alpha-mediated ET-1 synthesis and release (by 5-fold) and also significantly increased TNF-alpha- and ET-1-mediated hONA proliferation. PD142893 (1 microM), an ET(A/B) receptor antagonist, blocked ET-1-mediated hONA proliferation both under normoxia and hypoxia, while doing so only under normoxia following TNF-alpha treatment. Also, U0126 (10 microM; an upstream ERK1/2 inhibitor) completely blocked agonist-induced hONA proliferation in normoxia and partially blocked the same in hypoxia. These results demonstrate for the first time that hONAs secrete ET-1 and that TNF-alpha and hypoxia can regulate its levels. Moreover, hypoxia augments the proliferative responses of hONAs to TNF-alpha and ET-1. These agonist-mediated effects following hypoxia could contribute to astroglial activation as seen in glaucomatous optic nerve heads.

[Amiodarone treatment and visual prognosis]

BACKGROUND

Amiodarone is currently regarded as the most effective antiarrhythmic drug available for the treatment of tachyarrhythmias. Up to now, no recommendations exist concerning ophthalmological follow-up examinations at regular intervals of patients treated with amiodarone.

METHODS AND PATIENTS

We examined six patients with a mean age of 71.7 years (five men, one woman) who were treated with amiodarone.

RESULTS

One patient had no visual disturbances and a second patient had no permanent change of the optic nerve because treatment with amiodarone was discontinued in time. In one patient an abnormal blue colour vision was noticed. Swelling of the optic disc completely disappeared in five patients after discontinuing the drug. One patient revealed a posterior ischaemic optic neuropathy (PION). In two patients a unilateral change of the optic disc occurred. In three patients a severe irreversible lesion of the optic nerve was found at follow-up examination.

CONCLUSIONS

An insidious visual loss can occur with amiodarone treatment. A swelling of the optic disc without visual deterioration can occur as the first sign of a defect of the optic nerve. An abnormal blue colour vision can also be detected. After discontinuation of amiodarone either a visual improvement or a permanent deterioration may result. We recommend that every patient being treated with amiodarone should be observed by opthalmoscopy and colour vision examination at regular intervals (approximately every 3 months). Treatment with amiodarone should be discontinued after exclusion of life-threatening situations by a cardiologist, as soon as the first changes of the optic disc occur.

Response of choroidal blood flow to carbogen breathing in smokers and non-smokers

AIM

To investigate a potential difference in ocular vascular reactivity during carbogen breathing in optic nerve head, choroid, and retina between healthy smokers and non-smokers.

METHODS

25 (13 smokers and 12 non-smokers) healthy male volunteers participated in this observer masked, two cohort study. During inhalation of carbogen (5% CO(2) and 95% O(2)) over 10 minutes measurements were taken using laser Doppler flowmetry to assess submacular choroidal and optic nerve head blood flow, laser interferometry to assess fundus pulsation amplitudes, and retinal vessel analyser (RVA) to assess retinal vessel diameters.

RESULTS

At baseline choroidal blood flow was higher (p = 0.018, ANOVA) in smokers than in non-smokers. During administration of carbogen the response in choroidal blood flow was significantly different between the two groups: there was an increase in non-smokers after carbogen breathing (p = 0.048) compared with relatively stable blood flow in smokers (p = 0.049 between groups, ANOVA). A similar response pattern was seen for fundus pulsation amplitude, which increased notably after carbogen breathing in non-smokers but not in smokers (p<0.001 between groups, ANOVA). Optic nerve head blood flow and retinal vessel diameters were reduced in both groups to a comparable degree during carbogen breathing.

CONCLUSION

The study indicated abnormal choroidal vascular reactivity in chronic smokers. These early haemodynamic changes may be related to the increased risk to smokers of developing ocular vascular diseases. The specific mechanisms underlying abnormal choroidal vascular reactivity in chronic smokers remain to be characterised.

Effect of Acetazolamide on the Optic Disc Oxygenation in Miniature Pigs

BACKGROUND

The purpose of our study was to evaluate the variations of the optic disc PO (2) during normoxia and hyperoxia (100 % O (2)), before and after intravenous administration of acetazolamide.

MATERIAL AND METHODS

PO (2) measurements were obtained at intervascular areas of the optic disc in 11 anaesthetized miniature pigs using oxygen-sensitive microelectrodes introduced through the vitreous cavity by a micromanipulator. PO (2) was measured continuously during 10 minutes under systemic normoxia and systemic hyperoxia. Oxygen measurements were repeated under these conditions after intravenous injection of acetazolamide (bolus of 500 mg) in 8 animals.

RESULTS

In systemic hyperoxia, the optic disc PO (2) increased moderately (DeltaPO (2) = 4.7 +/- 2.5 mmHg; p < 0.001; n = 11) in parallel with systemic PaO (2). Acetazolamide led to a slow and progressive increase in the optic disc PO (2) (DeltaPO (2) = 2.1 +/- 1.7 mmHg; p > 0.1; n = 8 after 10 min, while DeltaPO (2) = 4.3 +/- 3.2 mmHg; p < 0.05; n = 8 after 30 min), in parallel with a slow and progressive increase in systemic PaCO (2). The optic disc PO (2) increased much more significantly after injection of acetazolamide under systemic hyperoxia (DeltaPO (2) = 13.3 +/- 3.1 mmHg; p < 0.001; n = 8).

CONCLUSIONS

Systemic hyperoxia alone is not sufficient to increase substantially the optic disc PO (2) in miniature pigs due to a vasoconstrictor effect. Intravenous injection of acetazolamide can increase the optic disc PO (2) progressively, due to a vasodilatory effect of elevated systemic PaCO (2). The association of acetazolamide injection with systemic hyperoxia can further improve the oxygenation of the optic disc.

Effect of exogenous neurotrophins on Trk receptor phosphorylation, cell proliferation, and neurotrophin secretion by cells isolated from the human lamina cribrosa

PURPOSE

Glaucoma is the number one cause of preventable blindness in the United States. The lamina cribrosa (LC) region of the optic nerve head (ONH) is a major site of injury in glaucomatous optic neuropathy. Neurotrophins (NTs), which include NGF, BDNF, NT-3, and NT-4, are growth factors involved in the development and support of neurons and in non-neuronal interactions. Cells within the human LC express high affinity tyrosine kinase receptors (Trks) for NTs. The purpose of this study was to determine if exogenous NTs cause (a) phosphorylation of Trk receptors in LC cells and ONH astrocytes and (b) cell proliferation and/or secretion of NTs by LC cells and ONH astrocytes.

METHODS

Trk phosphorylation in response to exogenous NGF, BDNF, NT-3, and NT-4 treatment was studied in LC cells and ONH astrocytes using immunoprecipitation and Western blotting. Cell number was assayed following treatment with exogenous NTs or the Trk phosphorylation inhibitor compound K-252a. Secretion of NTs following exogenous administration of NTs was determined using immunoassays.

RESULTS

LC cells and ONH astrocytes express Trk receptors that are phosphorylated in response to exogenous NTs. Autocrine/paracrine signaling was also evident by Trk phosphorylation in the absence of exogenous NT treatment. ONH astrocyte cell number increased following exogenous treatment with each NT. LC cell number increased following exogenous NGF or NT-3 treatment only. Treatment with the Trk phosphorylation inhibitor K-252a decreased both LC and ONH astrocyte cell number. Exogenous NT treatment increased the secretion of NGF by LC cells and ONH astrocytes. BDNF secretion by LC cells and ONH astrocytes was decreased by exogenous NT treatment.

CONCLUSIONS

LC cells and ONH astrocytes express functional Trk receptors that can be activated in response to exogenous NTs. The activation of Trk receptors expressed by LC cells and ONH astrocytes in the absence of exogenous NT treatment suggests autocrine/paracrine NT signaling may occur within the ONH. Neurotrophin signaling in LC cells and ONH astrocytes may regulate cell number and/or NT secretion within the LC region of the ONH.