Toshiyuki Oshitari

Changes of macular and RNFL thicknesses measured by Stratus OCT in patients with early stage diabetes.

PurposeTo examine the early differences in the thicknesses of the macula and retinal nerve fibre layer (RNFL) by Stratus optical coherence tomography in patients with diabetes mellitus.MethodsThirty-one normal participants without any optic nerve and retinal diseases (control), 45 diabetic patients without diabetic retinopathy (NDR), and 24 diabetic patients with preproliferative diabetic retinopathy (PPDR), who did not have clinically significant macular oedema, were used for the macular thickness measurements. Thirty control participants, 45 patients classified as NDR, and 22 patients classified as PPDR were used for the RNFL thickness measurements.ResultsIn patients with NDR, macula was significantly thinner than that of control eyes. In patients with PPDR, the mean RNFL thickness was significantly thinner but the macula was thicker than that of control eyes. In women with NDR, the macula was significantly thinner than that of men with NDR and that of normal women. In men with PPDR, the RNFL thickness was significantly thinner than that of the control eyes.ConclusionsAt the early stage of diabetic retinopathy, the maculas and RNFL thicknesses are altered. The macular and RNFL thicknesses are different in men and women.

Gene transfer into retinal ganglion cells by in vivo electroporation: a new approach

We developed a new in vivo electroporation method to deliver genes into retinal ganglion cells (RGCs). Efficiency and degree of tissue damage were evaluated using green fluorescent protein (GFP) gene and TUNEL. Soon after the intravitreous injection of the GFP gene, electroporation (five electric pulses of 99 ms duration each and 12V/cm delivered twice 5 min apart) was carried out on the adult rat eyeball with the aid of tweezer-type disc electrodes attached to corneal (cathode) and scleral (anode) surfaces. GFP expression, exhibiting a maximum on day 7, was detectable for up to 21 days. DiI retrograde labeling of RGCs showed that 41.5% of the total ganglion cells in the electroinjected area were GFP-positive. Therefore, this new method may be a useful tool for the delivery of genes into RGCs.

Foveal microstructure on spectral-domain optical coherence tomographic images and visual function after macular hole surgery.

PURPOSE To determine the correlation between the recovery of foveal microstructure and the visual acuity or the foveal sensitivity after idiopathic macular hole (MH) closure. DESIGN Prospective, consecutive, observational case series. METHODS We studied 43 eyes of 43 patients before and 1, 3, and 6 months after MH surgery. The best-corrected visual acuity (BCVA), the foveal sensitivity measured by MP1 microperimetry, and the photoreceptor inner and outer segment (IS/OS) junction and the external limiting membrane (ELM) determined by spectral-domain optical coherence tomography were investigated. RESULTS Preoperatively, the lengths of the IS/OS junction defect and the ELM defect were significantly correlated with only the foveal sensitivity (P<.0001). At all postoperative times, the lengths of both the IS/OS and ELM defects were significantly correlated with both the BCVA and the foveal sensitivity (P<.05 for all). The preoperative lengths of both the IS/OS and ELM defects were significantly correlated with the foveal sensitivity at 6 months after surgery (P=.0022, P=.0031, respectively). The IS/OS junction defect was significantly correlated with the ELM defect at all times (P<.0001 for all). No restoration of the IS/OS junction was observed in eyes without the ELM restoration. CONCLUSIONS The restoration of the ELM is closely associated with that of the IS/OS junction. The preoperative IS/OS or ELM defect was associated with the postoperative foveal sensitivity. The restoration of not only the IS/OS junction but also the ELM may reflect the morphologic and functional recovery of the foveal photoreceptors in surgically closed MHs.

Corneal Changes in Diabetes Mellitus

Diabetes mellitus is a major disease worldwide, and the prevalence of diabetes has risen significantly in the past several decades. Although one of the major complications of diabetic eyes is diabetic retinopathy (DR), corneal diseases can not only develop in diabetic patients but are also difficult to manage. Diabetic neurotrophic keratopathy is a component of diabetic polyneuropathy and is recognized to be the cause of the morbidity of the cornea in diabetic patients. In addition, corneal endothelial cell damage can cause disturbances in the management of proliferative DR before and after surgeries because of endothelial decompensation with bullous keratopathy. However, there have been only a limited number of studies that have focused on the importance of corneal diseases in diabetic patients. This review describes the pathophysiological roles of different factors that have been found to be causative factors of diabetic corneal keratopathy and endothelial cell dysfunction in diabetic patients. In addition, the clinical features of the corneal changes in diabetic patients and recent studies related to the development of therapies for the management of corneal diseases are presented.

Reduction of thickness of ganglion cell complex after internal limiting membrane peeling during vitrectomy for idiopathic macular hole

Background/aimThe aim of this study is to report a reduction in the thickness of the ganglion cell complex (GCC) after vitrectomy with internal limiting membrane (ILM) peeling in eyes with idiopathic macular hole (MH).MethodsTwenty-eight consecutive eyes with an idiopathic MH treated by vitrectomy with ILM peeling were studied. All eyes had an intravitreal injection of indocyanine green to make the ILM more visible. The best-corrected visual acuity (BCVA), GCC thickness measured by spectral domain optical coherence tomography, and retinal sensitivity measured by microperimetry were determined before and at 3 and 6 months after the vitrectomy.ResultsThe MH in all eyes was closed after the initial surgery. The BCVA was significantly improved at 3 and 6 months (P<0.001 and P<0.001, respectively). The thickness of the GCC was significantly reduced at 3 and 6 months postoperatively (P<0.001 and P<0.001, respectively). The GCC thickness was significantly correlated with the retinal sensitivity in the central 10 degrees at 6 months (r=0.55, P=0.004).ConclusionA reduction of the GCC thickness was observed after vitrectomy with ILM peeling for idiopathic MH.

Comparison of Vitrectomy with Brilliant Blue G or Indocyanine Green on Retinal Microstructure and Function of Eyes with Macular Hole

PURPOSE To evaluate the microstructure of the inner and outer retina and the visual function after macular hole (MH) surgery using brilliant blue G (BBG) or indocyanine green (ICG) to make the internal limiting membrane (ILM) more visible. DESIGN Comparative, retrospective, interventional case series. PARTICIPANTS Sixty-three eyes of 63 consecutive cases with MH were studied. Thirty-five eyes of 35 cases were treated with BBG between January and August 2011. Twenty-eight eyes of 28 MH cases were treated with ICG from April 2009 through April 2010. METHODS Vitrectomy was performed with a 23-gauge system and 0.25 mg/ml BBG or with 0.125% ICG. MAIN OUTCOME MEASURES The best-corrected visual acuity (BCVA) and the microperimetry-determined retinal sensitivity were measured at baseline and at 3 and 6 months after surgery. The length of the defect of the photoreceptor inner segment/outer segment (IS/OS) junction and external limiting membrane (ELM), the central foveal thickness (CFT), and the thickness of the ganglion cell complex (GCC) were measured in the spectral-domain optical coherence tomographic images. RESULTS The average BCVA was significantly better in the BBG group than in the ICG group at 3 months (P = 0.021) and 6 months (P = 0.045) after surgery. The mean retinal sensitivity in the BBG group was improved significantly in the central 2° at 3 and 6 months (P = 0.001 and P = 0.030, respectively), but was not significantly improved in the adjacent 10°. The length of IS/OS junction defect was significantly shorter in the BBG group at 3 months (P = 0.048), but was not significantly different at 6 months (P = 0.135). The length of ELM defect and the GCC thickness were not significantly different between the 2 groups at 3 and 6 months. The CFT was significantly thinner in the ICG group than in the BBG group at 3 and 6 months (P = 0.013 and P = 0.001, respectively). CONCLUSIONS The postoperative BCVA and retinal sensitivity in the central 2° were better in eyes after BBG-assisted vitrectomy. The restoration of IS/OS junction was faster in the BBG group, and the CFT was significantly thinner in eyes after ICG. Brilliant blue G may be a better agent than ICG to make the ILM more visible. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Citicoline has a protective effect on damaged retinal ganglion cells in mouse culture retina.

Some clinical reports indicate that exogenous CDP-choline (citicoline) may have a therapeutic effect in patients with glaucoma. However, the precise effect of citicoline on damaged retinal ganglion cells (RGCs) remains to be explained. We performed tissue culture of mouse retinal explants and investigated the effect of citicoline on damaged RGCs by the quantitative analysis of TdT-dUTP terminal nick-end labeling (TUNEL) staining and the assessment of the number of regenerating neurites. The TUNEL-positive ratio in 0.1–10 μmol/l citicoline-treated retina was very low, and the number of regenerating neurites increased more than in control retina. Our findings suggest that citicoline has a protective effect on damaged RGCs in tissue culture of retina.

Effect of neurotrophic factors on neuronal apoptosis and neurite regeneration in cultured rat retinas exposed to high glucose

The purpose of this study was to investigate the effect of brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and citicoline on neuronal apoptosis and neurite regeneration in cultured rat retinas exposed to high glucose (HG). The retinas of six adult Sprague-Dawley rats were studied. After the rats were euthanized, the retinas were isolated and cultured in serum-free medium. One group of explants was cultured in normal glucose (NG) and another group in HG medium (HGM). BDNF, NT-4, or citicoline were added to the HGM. After 7 days, the number of regenerating neurites was counted. Then, the explants were fixed, cryosectioned, and stained by TdT-dUTP terminal nick-end labeling (TUNEL), and also immunostained for the active-forms of caspase-3 and -9. The numbers of TUNEL-positive and caspase-3 and -9-immunopositive cells in the ganglion cell layer (GCL) were significantly higher, and the number of regenerating neurites was significantly lower in retinas cultured in HGM than in NG medium. Retinas incubated in HGM supplemented with BDNF, NT-4, or citicoline had significantly lower numbers of TUNEL-positive and caspase-3 and -9-immunopositive cells in the GCL, and the numbers of regenerating neurites were significantly higher than in HGM without these factors. We conclude that the increase in the number of apoptotic cells and decrease the number of regenerating neurites in the HGM indicate that HG is toxic to RGCs. The decrease in the number of apoptotic cells in the HGM containing BDNF, NT-4, or citicoline is correlated with the suppression of the caspase-9 and -3 activities.

Optic nerve regeneration within artificial Schwann cell graft in the adult rat.

We investigate whether an artificial graft made by cultured Schwann cell, extracellular matrix (ECM) and trophic factors can provide the environment for the regeneration of retinal ganglion cell (RGC) axons in adult rats. Six kinds of artificial grafts were used: ECM (control); ECM and Schwann cells; ECM, Schwann cells and either nerve growth factor, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4); ECM, Schwann cells, BDNF and NT-4, combined with intravitreal injection of BDNF. The grafts were transplanted onto the transected optic nerve. RGC regeneration was evaluated by dil retrograde labeling, immunohistochemistry, and electron microscopy at 3 weeks post-operation. The degree of dil labeled RGC was approximately 2% for ECM alone, and 10% for ECM and Schwann cells (p < 0.01). The labeling increased to approximately 20% by administration of neurotrophins. The addition of intravitreous BDNF injection resulted in highest labeling percentage of 30%. Immunohistochemical study showed that axons were association with GAP-43 and cell adhesion molecules. Neurotrophin receptors (Trk-A and Trk-B) were detected in nerve fibers both in the retina and in the graft. Remyelination was seen by electron microscopic observation. These results demonstrate that the regeneration of RGC axons is induced with the use of cultured Schwann cells and ECM as promoting factors for regrowth. The degree of regeneration was significantly increased by neurotrophins in the grafts and in the vitreous.

Two-Year Course of Subfoveal Pigment Epithelial Detachment in Eyes with Age-Related Macular Degeneration and Visual Acuity Better than 20/40

Purpose: To investigate the course of subfoveal pigment epithelial detachments (PEDs) in eyes with age-related macular degeneration (AMD) and best-corrected visual acuity (BCVA) ≥20/40. Methods: Thirty-seven eyes of 35 patients with a subfoveal PED were divided into an avascular PED group (n = 11), a vascularized PED group due to polypoidal choroidal vasculopathy (PCV, n = 14) and an occult choroidal neovascularization (CNV) group (n = 12). Intravitreal bevacizumab or ranibizumab was given as needed. The BCVA, central foveal thickness, PED thickness, and lesion size were measured at baseline and at 2 years after the initial examination. Results: The BCVA did not change significantly in the avascular group, decreased from 0.06 ± 0.11 to 0.23 ± 0.15 logMAR units in the PCV group and from 0.12 ± 0.12 to 0.71 ± 0.70 logMAR units in the CNV group. At 2 years, the central foveal and PED thicknesses were not significantly different among the 3 groups, and the lesion was significantly larger in the PCV and CNV groups than in the avascular group. Conclusions: The vascularized PED cases had a poorer visual outcome than avascular PEDs with anti-VEGF drugs at the 2-year follow-up.