Vergleich verschiedener viraler Vektoren zur Gentherapie von Hornhautendothelzellen

Aim

In this paper we compare the transduction efficiency, toxicity, and safety of retroviral vectors [equine infectious anemia virus (EIAV), human immunodeficiency virus-1 (HIV-1), human foamy virus (PFV] and adenovirus (Ad) for potential use in gene therapy of corneal endothelial cells.

Method

Murine corneal endothelial cells were transduced with EIAV, HIV-1, PFV, and Ad, resulting in the overexpression of a green fluorescent protein (eGFP) transgene marker. The transduction efficiency was assessed by flow cytometry, while cytotoxicity and apoptosis rate were detected by annexin V/propidium iodide (PI) stain.

Results

Ad had the highest transduction efficiency with 99% of the cells expressing the transgene, followed by EIAV (95%), HIV-1 (75%), and PFV (43%). However, the high transduction efficiency of Ad also resulted in the highest apoptosis rate (25%) in the corneal endothelial cells. There was no detectable difference in the toxicity between PFV and HIV-1 (10%). EIAV transduction had the lowest cytotoxicity, with only 3% of the cells being annexin V/PI positive.

Conclusion

Compared to other vectors EIAV exhibited high transduction efficiency combined with low toxicity to corneal endothelial cells. Therefore, it is a powerful tool for gene therapy applications in selected corneal endothelial diseases.     

Properties of Corneas Reconstructed with Cultured Human Corneal Endothelial Cells and Human Corneal Stroma

Purpose

To examine the properties of corneas tissue-engineered with cultured human corneal endothelial cells (HCEC) and human corneal stroma.

Methods

Primary HCEC cultures were established from endothelial cell layer explants and propagated on culture dishes coated with bovine corneal endothelial extracellular matrix. A cell suspension of HCEC at the fifth passage was transferred onto human corneal stroma deprived of endothelial cells, and the corneas were gently centrifuged to enhance cell attachment. The cell density of the tissue-engineered corneas was examined after staining with alizarin red and trypan blue. The tissue-engineered corneas were histologically examined by light and electron microscopy. The pump function of the tissue-engineered corneas was measured using an Ussing chamber.

Results

The mean endothelial cell density of four tissue-engineered corneas was 2380 ± 264 cells/mm² (mean ± SD). HCEC on the tissue-engineered corneas had a morphology similar to HCEC in vivo. The pump function parameters of the tissue-engineered corneas were 55%–75% of those of normal corneas.

Conclusions

HCEC on the tissue-engineered corneas have morphology and cellular density similar to HCEC in vivo, whereas the pump function of the tissue-engineered corneas was lower than in normal corneas. Jpn J Ophthalmol 2005;49:448–452 © Japanese Ophthalmological Society 2005     

m4-muskarinerge Rezeptoren der Hornhaut

Background

Muscarinic cholinoceptors have been found in all types of ocular tissue, e.g. in corneal epithelium and endothelium. Latest research has focused only on the m5 cholinoceptor subtype. However, previous studies have also indicated the presence of m2 or m4 receptor subtypes in corneal tissue. The aim of this study was to show the decrease of intracellular cAMP formation and protein kinase A (PKA) activity after stimulation of m2 or m4 cholinoceptors in bovine corneal epithelial and endothelial cells.

Materials und methods

Muscarinic cholinoceptors were studied using polyclonal antibodies. The cAMP concentration was determined with an enzyme immunoassay and PKA activity was estimated by the consumption of ATP.

Results

Immunocytochemistry, immunofluorescence and immunoblotting revealed the presence of the m4 muscarinic cholinoceptor subtype but not of the m2 receptor subtype in bovine corneal epithelial and endothelial cells. In bovine corneal epithelium and endothelium protein cAMP formation was decreased and PKA activity was inhibited by acetylcholine in a dose-dependent manner (p<0.001).

Conclusion

The findings indicate that stimulation of m4 muscarinic cholinoceptors inhibits the cAMP-PKA pathway in corneal epithelial and endothelial cells resulting in decreased protein kinase A activity. Further work will be needed to clarify the physiological role of this signaling pathway in corneal epithelium and endothelium.     

DMEK: posteriore lamelläre Keratoplastiktechnik

Background

Penetrating keratoplasty is at present the gold standard for surgical treatment of corneal endothelial pathologies but tremendous progress has been made in recent years in improving the technology of (posterior) lamellar keratoplasty techniques, such as Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

A review of the literature was carried out using PUBMED and own clinical and experimental data.

Results

Isolated transplantation of Descemet’s membrane with endothelial cells after stripping the host Descemet’s membrane is a new surgical technique for Fuchs endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation seems to be faster and better with DMEK compared to penetrating keratoplasty.

Conclusion

Posterior lamellar keratoplasty techniques such as DMEK will replace penetrating keratoplasty as the gold standard for treatment of a large segment of corneal endothelial pathologies.     

Impact of photodynamic inactivation (PDI) using the photosensitizer chlorin e6 on viability, apoptosis, and proliferation of human corneal endothelial cells

Background

Photodynamic inactivation (PDI) may be a potential alternative in case of therapy-resistant infectious keratitis. PDI using the photosensitizer chlorin e6 (Ce6) with high photosensitizing efficacy offers a valuable option, also for keratitis. The purpose of our study was to determine the impact of PDI with the photosensitizer Ce6 on viability, apoptosis, and proliferation of human corneal endothelial cells (HCECs), in vitro.

Methods

Human corneal endothelial cell line was cultured in DMEM/Ham’s F12 medium supplemented with 5 % fetal calf serum. HCECs cultures underwent illumination using red (670 nm) light for 13 min following exposure to 50–500 nM concentrations of Ce6 in the culture medium. Twenty-four hours after PDI, cell viability was evaluated by the Alamar blue assay, total DNA content of the cells and apoptosis using the APO-DIRECT? Kit, and cell proliferation by the BrdU Cell Proliferation Assay Kit.

Results

Using Ce6 or illumination only, we did not detect significant changes of cell viability, apoptosis, and proliferation. Following PDI, viability and total DNA content of HCECs decreased significantly above 150 nM Ce6 concentration (P?<?0.01; P?<?0.05). The percentage of apoptotic HCECs increased significantly from 250 nM Ce6 concentration (P?<?0.01), and proliferation of endothelial cells decreased significantly (P?<?0.05) above 100 nM concentration of Ce6 after PDI.

Conclusions

Photodynamic inactivation using Ce6 decreases viability and proliferation, and also triggers apoptosis of HCECs in vitro. PDI using the photosensitizer Ce6 may be a potential treatment alternative in infectious keratitis. However, to avoid endothelial cell damage, the photosensitizer must not penetrate the endothelium.     

Verminderung der Lipidperoxidation und der Apoptoserate in kornealen Endothelzellen durch Vitamin A

PURPOSE: The goal of this study was to determine the effects of lipid peroxidation-mediated toxicity of iron ions on corneal endothelial cells leading to apoptosis. METHODS: Murine corneal endothelial cells were maintained in tissue culture medium supplemented with free iron ions, known to lead to increased lipid peroxidation. Retinoic acid in the cell supernatant and cytoplasm of these cells was determined using HPLC. The rate of apoptosis was assessed by quantification of caspase-3-like activity. The lipid peroxidation was measured using the malondialdehyde method. Supplementation of retinoic acid was tested in the setting of apoptosis. RESULTS: Free iron ions led to a rapid loss of retinoic acid in the supernatant and the corneal endothelial cells. This was correlated with rising levels of malondialdehyde following oxidative stress and increased apoptosis. Supplementation of retinoic acid alone significantly reduced oxidative stress and apoptosis in the respective cells. CONCLUSION: In this study the authors present a novel in vitro model to test the direct influence of pro-oxidative species on corneal endothelial cells. The authors also prove that supplementing corneal endothelial cells with retinoic acid sufficiently prevents free radical injury and apoptosis.     

Posteriore lamelläre Keratoplastik (DSAEK)

Background

Although penetrating keratoplasty remains the gold standard for surgically treating corneal endothelial pathologies, tremendous progress has been made in recent years to improve the technology of (posterior) lamellar keratoplasty.

Methods

Literature review from PubMed and own data.

Results

Posterior lamellar keratoplasty using a microkeratome (Descemet’s stripping with automated endothelial keratoplasty, or DSAEK) is a reliable surgical technique for Fuchs’ endothelial dystrophy and pseudophakic bullous keratopathy. Visual rehabilitation is faster with lamellar keratoplasty than penetrating keratoplasty.

Conclusion

Posterior lamellar keratoplasty techniques such as DSAEK will become an important surgical treatment option for corneal endothelial pathologies.     

Long-term follow-up of changes in corneal endothelium after primary and secondary intraocular lens implantations in children

Background

To evaluate long-term changes in corneal endothelial cell count and morphology after congenital cataract extraction and intraocular lens implantation.

Methods

Cataract extraction and posterior chamber intraocular lens (IOL) implantation was performed on 54 congenital cataract patients (83 eyes). The corneal endothelial cell density (ECD), coefficient of variation (CV), hexagonality, and central corneal thickness (CCT) were measured for a retrospective analysis of long-term changes in corneal endothelial characteristics.

Results

The mean age at the time of IOL implantation was 5.00 (3.62) years [mean (SD)], and the mean follow-up period was 8.83 (1.49) years. In a comparison of the treated and normal eyes of patients who underwent unilateral surgery, the treated eyes showed a significantly greater CCT (p?<?0.05), and there was no significant difference in ECD, CV, and hexagonality (p?>?0.05). In addition, there was no statistically significant difference in the ECD and CCT between the primary and secondary IOL implantation groups.

Conclusions

Our results did not show any significant corneal endothelial cell loss in congenital cataract patients; however, their CCTs were increased.     

Quality assessment of corneal storage media and their components

Background

To keep the loss of endothelial cell density in donor corneas to a minimum, a storage medium which is adjusted to their nutritional needs is necessary. Different media, used either serum-supplemented or serum-free, are available. The quality of medium- and serum-batches as well as support of endothelial cell viability by the medium are to be tested with a quality assured screening system that allows routine examination.

Methods

A screening system was developed which is based on cell-culture tests with the well-established human corneal endothelial cell line HCEC-12, and therefore can be performed without the need for donor corneas. The cells are plated at a defined density in cell-culture dishes, and are cultured for a defined period of time in the test media. Evaluation is carried out by assaying cell count, activity of cell metabolism (resazurin conversion), and determining the number of apoptotic and necrotic cells (combined vital staining with YO-PRO®-1/propidium iodide and subsequent flow cytometry).

Results

Human corneal endothelial cells that are cultured in a medium which is adjusted to their nutritional needs achieve higher cell numbers and show a higher metabolic rate. Simultaneously, the percentage of apoptotic and necrotic cells is lower. The screening system developed in this study allows for easy and reliable detection of slightest differences between different media, different processing steps for same media, and different supplements, as well as different serum batches.

Conclusions

The differentiated results show that the screening system is sensitive enough to show even minor quality differences. Therefore, it is more suitable than the hitherto commonly used growth assay with primary, mostly porcine, corneal endothelial cells.     

Mitochondria-targeted antioxidant SKQ1 protects cornea from oxidative damage induced by ultraviolet irradiation and mechanical injury

Background

Cornea protects the eye against natural and anthropogenic ultraviolet (UV) damage and mechanical injury. Corneal incisions produced by UV lasers in ophthalmic surgeries are often complicated by oxidative stress and inflammation, which delay wound healing and result in vision deterioration. This study trialed a novel approach to prevention and treatment of iatrogenic corneal injuries using SkQ1, a mitochondria-targeted antioxidant approved for therapy of polyethiological dry eye disease.

Methods

Rabbit models of UV-induced and mechanical corneal damage were employed. The animals were premedicated or treated with conjunctival instillations of 7.5?μM SkQ1. Corneal damage was assessed by fluorescein staining and histological analysis. Oxidative stress in cornea was monitored by measuring malondialdehyde (MDA) using thiobarbituric acid assay. Total antioxidant activity (AOA) was determined using hemoglobin/H₂O₂/luminol assay. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were measured using colorimetric assays.

Results

In both models corneas exhibited fluorescein-stained lesions, histologically manifesting as basal membrane denudation, apoptosis of keratocytes, and stromal edema, which were accompanied by oxidative stress as indicated by increase in lipid peroxidation and decline in AOA. The UV-induced lesions were more severe and long healing as corneal endothelium was involved and GPx and SOD were downregulated. The treatment inhibited loss of keratocytes and other cells, facilitated re-epithelialization and stromal remodeling, and reduced inflammatory infiltrations and edema thereby accelerating corneal healing approximately 2-fold. Meanwhile the premedication almost completely prevented development of UV-induced lesions. Both therapies reduced oxidative stress, but only premedication inhibited downregulation of the innate antioxidant activity of the cornea.

Conclusions

SkQ1 efficiently prevents UV-induced corneal damage and enhances corneal wound healing after UV and mechanical impacts common to ocular surgery. Its therapeutic action can be attributed to suppression of mitochondrial oxidative stress, which in the first case embraces all corneal cells including epitheliocytes, while in the second case affects residual endothelial cells and stromal keratocytes actively working in wound healing. We suggest SkQ1 premedication to be used in ocular surgery for preventing iatrogenic complications in the cornea.

     

Mapping owl’s eye cells of patients with cytomegalovirus corneal endotheliitis using in vivo laser confocal microscopy

Purpose

To produce a two-dimensional reconstruction map of owl’s eye cells using in vivo laser confocal microscopy in patients with cytomegalovirus (CMV) corneal endotheliitis, and to demonstrate any association between owl’s eye cells and coin-shaped lesions observed with slit-lamp biomicroscopy.

Method

Two patients (75- and 77-year-old men) with polymerase chain reaction-proven CMV corneal endotheliitis were evaluated in this study. Slit-lamp biomicroscopy and in vivo laser confocal microscopy were performed. Images of owl’s eye cells in the endothelial cell layer were arranged and mapped into subconfluent montages. Montage images of owl’s eye cells were then superimposed on a slit-lamp photo of the corresponding coin-shaped lesion. Degree of concordance between the confocal microscopic images and slit-lamp photos was evaluated.

Results

In both eyes, a two-dimensional reconstruction map of the owl’s eye cells was created by computer software using acquired confocal images; the maps showed circular patterns. Superimposing montage images of owl’s eye cells onto the photos of a coin-shaped lesion showed good concordance in the two eyes.

Conclusions

This study suggests that there is an association between owl’s eye cells observed by confocal microscopy and coin-shaped lesions observed by slit-lamp biomicroscopy in patients with CMV corneal endotheliitis. The use of in vivo laser confocal microscopy may provide clues as to the underlying causes of CMV corneal endotheliitis.     

Einfluss der Spenderlamellendicke auf die Sehschärfe nach „Descemet’s stripping automated endothelial keratoplasty“ (DSAEK)

Background

The aim of this study was to evaluate the effect of donor lamella thickness on postoperative visual acuity after Descemet’s stripping automated endothelial keratoplasty (DSAEK).

Materials and methods

A retrospective analysis of 65 eyes from 61 patients who underwent DSAEK surgery in cases of Fuchs’ corneal dystrophy or bullous keratopathy between 2008 and 2011 was performed. The thickness of donor lamella was measured intraoperatively by ultrasonic pachymetry and postoperatively by anterior segment optical coherence tomography (OCT) and correlated to the visual acuity and number of endothelial cells.

Results

The donor lamella thickness measured intraoperatively and postoperatively correlated significantly with each other (r?=?0.874, p?<?0.001). A significant correlation was found between postoperative corneal lamella thickness measured by anterior segment OCT and visual acuity (r?=?0.273, p?=?0.028) but not between intraoperative donor lamella thickness measured by ultrasonic pachymetry and visual acuity (r?=?0.241, p?=?0.103). The postoperative endothelial cell number did not show a correlation with either the intraoperatively or the postoperatively measured donor lamella thickness (r?=???0.059, p?=?0.731, r?=?0.024, p?=?0.869, respectively).

Conclusions

Corneal lamella thickness <?120 µm was found to be correlated with a better visual outcome than in cases of thicker corneas >?120 µm. Despite greater difficulty in corneal transplant technique in cases of thinner lamella no increased damage of corneal endothelium was shown. Therefore, DSAEK with corneal lamella thickness <?120 µm is an interesting therapeutic alternative to DMEK.     

Supplementation with antioxidants attenuates transient worsening of retinopathy in diabetes caused by acute intensive insulin therapy

Background

To investigate whether insulin can increase the production of reactive oxygen species (ROS) in bovine retinal microvascular endothelial cells (BRECs), the role of antioxidants in the insulin-induced exacerbation of diabetic retinopathy and the related mechanisms.

Methods

BRECs were cultured in either 5 or 30?mM glucose for 3?days before stimulation with 100?nM insulin for 24?h or incubated with 1?mM apocynin, 100?μM LY294002, 50?μM U0126, 2?μM GF109203X, 250?U/ml catalase, 100?μg/ml ascorbic acid, 100?μM α-lipoic acid and 50?μM α-tocopherol before stimulation with 100?nM insulin. H₂O₂ (200?μM) was added to cells to measure the VEGF protein expression. Intracellular ROS was measured by immunofluorescence and flow cytometry, superoxide anion measurement was done by cytochrome c reduction, and VEGF protein was measured by ELISA analysis.

Results

Insulin or (and) high glucose significantly increased intracellular ROS production in BRECs, and pretreatment of the cells with apocynin and LY294002 decreased insulin-induced superoxide anion production. Neither pretreatment with GF109203X nor U0126 showed an effect on the superoxide anion production. Ascorbic acid, α-lipoic acid, and α-tocopherol also decreased superoxide anion production. Furthermore, H₂O₂ increased VEGF protein expression in BRECs and catalase suppressed insulin-induced VEGF protein expression.

Conclusions

Insulin can increase ROS production through an NAD(P)H, phosphatidylinositol 3′-kinase-dependent mechanism in bovine retinal microvascular endothelial cells ex vivo. ROS can regulate insulin-induced VEGF expression. Supplementation with antioxidants may help to attenuate the transient worsening of retinopathy in diabetes caused by acute intensive insulin therapy.     

Blockade of the VEGF isoforms in inflammatory corneal hemangiogenesis and lymphangiogenesis

Background

The VEGF-A family plays a crucial role in the induction of pathological corneal neovascularization. The role of the different VEGF-A isoforms during lymphangiogenesis is only little-known. Current anti-angiogenic therapies in the eye and other organs inhibit all VEGF-A isoforms, and have effects on both blood and lymphatic vessels. Here we investigate whether selective targeting of the isoform VEGF 165 is able to inhibit corneal lymphangiogenesis under inflammatory conditions.

Methods

The mouse model of suture-induced corneal neovascularization was used to assess the antihem- and antilymphangiogenic effect of topically applied pegaptanib. Corneal blood and lymph vascularized areas were analyzed morphometrically. Furthermore, we analyzed the proliferative effects of VEGF A 121, 165, and 189 on blood and lymphatic endothelial cells (BEC/LEC) via a cell-proliferation assay.

Results

Pegaptanib significantly inhibited inflammatory corneal hemangiogenesis (p?<?0.01), but not lymphangiogenesis in vivo (p?>?0.05), both topically as well as systemically, in the inflamed cornea. In vitro, BECs were more susceptible to pegaptanib than LECs.

Conclusions

Targeting VEGF-A 165 significantly inhibits hem- but not lymphangiogenesis, suggesting VEGF-A 165 to be critical for hem-, but dispensable for lymphangiogenesis, at least in the inflamed cornea.     

Konfokale In-vivo-Hornhautmikroskopie nach Keratoplastik

Background

Seven eyes with clear grafts after penetrating keratoplasty were examined with in vivo confocal corneal microscopy in 1999. Our aim was the confocal microscopic investigation of the subclinical changes in clear grafts after long-term follow-up.

Methods

The preoperative diagnoses were keratoconus (two), granular corneal dystrophy (two), pseudophakic bullous keratopathy due to ACL (two), and corneal ulcer (one). The epithelium, corneal nerves, keratocytes of the anterior and posterior stroma, and endothelium were evaluated with confocal microscopy.

Results

Mean density of basal epithelial cells was 3928±378 cells/mm² at 15 months and 3284±565 cells/mm² at 66 months postoperatively. At 15 months the keratocyte density was 750±113 cells/mm² in the anterior stroma and 601±98 cells/mm² in the posterior stroma, at 66 months 383±53 cells/mm² in the anterior stroma and 411±98 cells/mm² in the posterior stroma. Endothelial cell density decreased from 1719±576 cells/mm² (15 months) to 965±272 cells/mm² (66 months).

Conclusions

In the follow-up period a significant decrease of keratocyte and endothelial cell density was detectable with confocal microscopy. The clinical importance of our findings must be clarified with further examinations on more patients.     

Komplikationsvermeidung und -management bei „Descemet membrane endothelial keratoplasty“ (DMEK) und „Descemet stripping automated endothelial keratoplasty“ (DSAEK)

Background

Posterior lamellar keratoplasty, in the form of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), has become a standard procedure for therapy of endothelial diseases of the cornea. The aim of this article is to describe strategies to prevent and manage complications in DMEK and DSAEK surgery.

Methods

The article is based on a PubMed literature search and own clinical data. Key words used were “DMEK”, “DSAEK”, “Descemet membrane endothelial keratoplasty” and “Descemet stripping automated endothelial keratoplasty”.

Results

The DMEK and DSAEK procedures are safe surgical strategies for treating endothelial corneal diseases if the indications are made correctly.

Conclusions

The DMEK procedure is the standard procedure for improvement of visual acuity especially for younger patients with Fuchs’ dystrophy and DSAEK is particularly suitable for eyes with complicated anterior chamber situations.     

Comparison of clear corneal incision injuries between torsional and conventional phacoemulsification

Purpose

To compare thermal and mechanical clear corneal incision (CCI) injuries after conventional and torsional phacoemulsification.

Design

A prospective, randomized clinical study.

Methods

A total of 80 eyes were evaluated for the profile of the incision at 1 day and 3 months postoperatively. The wound architecture was recorded with anterior segment optical coherence tomography (AS-OCT). The incisional thickness increased by thermal injury, Descemet’s membrane detachment (DMD) caused by mechanical injury, the presence of endothelial gaping, loss of coaptation, and wound retraction of the conventional phaco group and the torsional phaco group were compared.

Results

The corneal thickness at the incision site of the torsional ultrasound group was significantly lower than the conventional group compared to at the first postoperative visit (1187.55?±?75.66, 1233.62?±?85.87, P?=?.013). However, this thickness was similar between the two groups at 3 months postoperatively. The central endothelial cell loss was significantly lower in the torsional ultrasound group after 3 months (417?±?143, 322?±?130, P?=?.003). There was a positive correlation between cumulated dissipated energy (CDE) and the incisional corneal thickness change that was observed by AS-OCT. Other OCT outcome parameters (such as endothelial gap, DMD, epithelial gap, and uncoaptation) that may be caused by mechanical injury did not differ significantly between the groups on postoperative day one or after 3 months.

Conclusions

The torsional ultrasound mode may provide a lower level of phacoemulsification time and energy and induce less incisional corneal thickness caused by thermal injury in the early postoperative period. The long-term wound healing appeared the same in both ultrasound mode groups.     

Descemet's stripping endothelial keratoplasty (DSEK) for children with congenital hereditary endothelial dystrophy: surgical challenges and 1-year outcomes

Purpose

To evaluate the outcomes of Descemet's stripping endothelial keratoplasty (DSEK) in patients with congenital hereditary endothelial dystrophy (CHED).

Methods

Retrospective, interventional case series of five eyes of five patients with congenital hereditary endothelial dystrophy (CHED) undergoing Descemet's stripping endothelial keratoplasty (DSEK) from June 2009 to June 2010 by a single surgeon. Patients were evaluated during the postoperative period for visual acuity, refraction, corneal clarity, lenticule status, and intraocular pressure. Anterior segment ocular coherence tomography (OCT) and confocal microscopy were performed when possible.

Results

Three male and two female children with an average age of 7.8?years (range 5–12?years) with CHED underwent DSEK. Surgery was uneventful in all patients and the lenticules stayed attached during the postoperative period. All the patients had 1-year follow-up. Corneal clarity improved in all the patients over the period of follow-up. Anterior segment OCT showed a gradual reduction in the thickness of the central corneal thickness and the graft over a period of time.

Conclusions

DSEK is a viable alternative to penetrating keratoplasty in patients with CHED with distinct advantages of reduced postoperative astigmatism and potential reduction of postoperative complications.     

Regeneration of the human corneal endothelium

The ability of the human corneal endothelium to regenerate is studied with the scanning electron microscope through examples of corneal diseases and penetrating keratoplasties. This study does not lead to final conclusions on the possibilities of regeneration of the human corneal endothelium but allows us to say that:

regeneration occurs through size increasing and deformation of the remaining cells.

the increase in number and size of surface microvilli may simply indicate a state of cell activation.

the présence of two nuclei in one cell is probably obtained by amitotic division but no complete mitosis has been seen.

Displacement of endothelial cells is a real progression and the cell is able to overcome obstacles.

the fibroblastic transformation of the endothelial cells is present in man but this may simply represent the migrating form of the cells.

     

An Asian Patient with Intraocular Lymphoma Treated by Intravitreal Methotrexate

Background

To demonstrate the efficacy of intravitreal methotrexate for treating intraocular lymphoma.

Case

A 55-year-old immunocompetent Asian man was diagnosed with intraocular lymphoma.

Observations

The patient was initially managed by intravenous administration of high-dose methotrexate. Because vitreous cells persisted after systemic chemotherapy, methotrexate was given intravitreally thereafter. There was only self-limited corneal epitheliopathy without major complications following intraocular injections. Ocular remission was sustained during a 21-month follow-up.

Conclusion

Intravitreal methotrexate is an effective, repeatable, and safe treatment for intraocular lymphoma.?Jpn J Ophthalmol 2006;50:474–478 © Japanese Ophthalmological Society 2006