Perceived Stress Levels in Adult Patients With Uveitis.

Background: The aim of this study was to examine perceived stress levels in adult patients with uveitis. Patients and Methods: One hundred seventy-three adult consecutive uveitis patients (age range 18 to 85 years) were analyzed in a cross-sectional design for their perceived stress, according to the Perceived Stress Questionnaire (PSQ). Stress levels were classified into normal stress, moderate stress, and high stress. Results: In the majority of uveitis patients a normal stress level (82%) within the last 2 years was detected. In a subgroup analysis, perceived stress of the patients with active uveitis compared with patients with non-active uveitis was significantly higher within the last 2 years (n=80 active/n = 45 non-active; p = 0.005). Conclusions: Overall 18% of the uveitis patient had raised perceived stress, similar to the general population but patients with active uveitis were significantly more stressed. Therefore, consideration of stress levels may be important in the therapy of uveitis patients.

Epithelial-Mesenchymal Transition (EMT)-Related Cytokines in the Aqueous Humor of Phakic and Pseudophakic Fuchs' Dystrophy Eyes.

PURPOSE: The present study aimed to analyze the expression of epithelial-mesenchymal transition (EMT)-related cytokines in the aqueous humor of phakic and pseudophakic Fuchs' endothelial corneal dystrophy (FECD) eyes and their correlation to FECD severity. METHODS: Aqueous humor samples from phakic FECD eyes (FECDph, n = 9), from pseudophakic FECD eyes more than 1 year after cataract surgery (FECDpsph, n = 13), and from cataract controls without FECD (Controlcat, n = 28) were obtained during Descemet membrane endothelial keratoplasty (DMEK) or cataract surgery. Expression of EMT-related cytokines (TGF-ß1, TGF-ß2, TGF-ß3, MCP-1, BFGF, TNF-α, IL-1ß) was measured using multiplex bead assay. Corneal central-to-peripheral thickness ratio at 3.5 mm from the center (CPTR3.5) was determined as an objective metric for FECD severity before surgery by slit-scanning pachymetry. RESULTS: Pseudophakic FECD eyes showed significantly elevated expression compared with Controlcat and FECDph eyes for TGF-ß1 (P < 0.001, respectively), for TGF-ß2 (P < 0.05, respectively), and MCP-1 (P < 0.001, respectively). Levels of TGF-ß1 (r = 0.6116, P < 0.05) and MCP-1 (r = 0.5934, P < 0.05) were positively correlated with CPTR3.5. No differences in EMT-associated protein levels were detected comparing FECDph eyes and Controlcat eyes. CONCLUSIONS: Simultaneous elevation of TGF-ß1, TGF-ß2, and MCP-1 concentrations in FECDpsph eyes confirms that cataract surgery leads to long-term alterations of the intraocular microenvironment. Positive correlation of increased aqueous TGF-ß1 and MCP-1 levels with CPTR3.5 in pseudophakic FECD eyes suggests that changed cytokine levels may be involved in corneal decompensation after cataract surgery. Unchanged aqueous humor levels of EMT-related proteins analyzed in phakic FECD patients indicate that there is no primary role of these aqueous cytokines in FECD pathogenesis.

The effect of previous surgery and topical eye drops for primary open-angle glaucoma on cytokine expression in aqueous humor.

PURPOSE: To evaluate cytokine expression in the aqueous humor of patients with primary open-angle glaucoma (POAG) after previous glaucomatous and/or cataract surgery, and to determine the effect of intraocular pressure (IOP)-lowering eye drops on cytokine expression. METHODS: This prospective consecutive case study included 32 eyes diagnosed with POAG (19 with previous surgery and 13 without previous surgery, treated with topical antiglaucoma medication) and 12 eyes without signs of glaucoma. The Luminex 200 multiplex bead immunoassay was used to measure 27 cytokines in aqueous humor. RESULTS: Eyes suffering from POAG, with previous surgery, had significantly elevated concentrations of IL-6, IL-8, CCL2, CXCL9, and HGF, and a significantly lower concentration of CCL5, compared to POAG eyes without previous surgery, treated only with topical antiglaucoma medication. When compared with cataract controls, eyes with POAG and previous surgery had significantly elevated levels of G-CSF, IL-8, IL-12, CXCL10, and HGF, and significantly decreased concentrations of IL-17, CCL5, and VEGF in aqueous humor. In a comparison between POAG eyes without previous surgery and cataract controls, the cataract control eyes had significantly higher levels of IL-6 and CCL2, as the only significant difference. CONCLUSIONS: POAG is associated with an aqueous inflammatory response in the aqueous humor, which is significantly elevated in eyes with previous surgery. In contrast, preoperative IOP-lowering eye drops did not significantly alter the anterior chamber milieu. The results of the current study indicate that filtration surgery has a higher success rate in eyes that have not experienced previous surgery.

The neuroprotective potential of Rho-kinase inhibition in promoting cell survival and reducing reactive gliosis in response to hypoxia in isolated bovine retina.

AIMS: To investigate the outcomes of Rho-kinase inhibition in the electrophysiological ex vivo model of the isolated perfused vertebrate retina under hypoxia. METHODS: Bovine retinas were perfused with an oxygen saturated nutrient solution with or without the Rho-kinase inhibitor H-1152P. The retinas were stimulated repeatedly until stable amplitudes were reached and the electroretinogram was recorded at five minute intervals. Hypoxia was induced for 15, 30, and 45 minutes, after which the oxygen saturation was restored. The extent of the cell damage and glial reactivity was determined by Ethidium homodimer-1 staining, immunohistochemistry, and Western blot. RESULTS: Hypoxia caused a time-dependent reduction of the b-wave amplitudes, which could not be prevented by the H-1152P. Although the Rho-kinase inhibitor maintained higher b-wave amplitudes, these effects did not reach statistical significance. Hypoxia also resulted in an increase in cell damage and the activation of the glial cells in the untreated retinas whereas the administration of H-1152P significantly reduced the extent of these events. CONCLUSION: H-1152P exerted a neuroprotective effect against necrosis on the isolated bovine retina under hypoxia together with a reduction in glial cell reactivity. However, the inhibitor could not prevent the hypoxia induced retinal dysfunction possibly due to the interference with synaptic modulation.

Retrospective analysis of the success and safety of Gold Micro Shunt Implantation in glaucoma.

BACKGROUND: To evaluate the success rate and adverse effects of Gold Micro Shunt Plus (GMS+) implantation into the supraciliary space. METHODS: This retrospective study included 31 eyes of 31 patients diagnosed with severe glaucoma and uncontrolled intraocular pressure (IOP) with implantation of a GMS+ by means of a full-thickness scleral flap. The main outcome measures were surgical failure or success, based on the intraocular pressure and adverse effects. Clinical examination data are reported up to 4 years postoperatively. RESULTS: Thirty eyes (97%) met one of our criteria for failure. Within a mean of 7.3 ± 7.7 months another surgery was performed because of elevated IOP in 24 of 31 eyes (77%) and because of adverse effects in 2 (6%). The remaining 4 eyes, that met one of our criteria for failure, had an IOP reduction of less than 20% with comparable medication. Six GMS+'s were explanted; because of IOP elevation, 2; rubeosis iridis, 2; and low grade inflammation, 2. CONCLUSIONS: GMS+ implantation is not an effective method to control IOP in patients with glaucoma, when using our surgical technique. The reason for the found signs of chronic low grade inflammation or rubeosis iridis in 4 eyes (13%) remains unknown and has to be further investigated.

A new rebound tonometer for home monitoring of intraocular pressure.

BACKGROUND: To compare intraocular pressure (IOP) measurements obtained by the Icare ONE rebound tonometer (RTONE) and the Goldmann applanation tonometer (GAT) in healthy persons and glaucoma patients in a prospective study, and to investigate the influence of central corneal thickness (CCT). METHODS: Measurements on 126 right eyes were obtained by three equally skilled ophthalmologists with each of the above-mentioned tonometers. In addition, patients measured their own IOP with the RTONE (RTONE(p)). The means and standard deviation for all tonometers were compared. Agreement between the tonometers was calculated using the Bland-Altman method. RESULTS: A total of 95 (75.3%) patients were able to perform correct self-tonometry. Mean IOPs obtained were 17.1 ± 5.9 mmHg (RTONE performed by ophthalmologist: RTONE (o)), 17.3 ± 5.6 mmHg (RTONE(p)) and 16.5 ± 5.1 mmHg (GAT). Correlation analysis indicated a good correlation between IOP readings obtained using RTONE(o) and RTONE(p) (ρ = 0.916; p < 0.001) and RTONE(o) and GAT (ρ = 0.901; p < 0.001). Bland-Altman analysis revealed a mean difference (bias) between RTONE(o) and RTONE(p), between RTONE(o) and GAT, and between RTONE(p) and GAT of -0.2, 0.6, and 0.8 mmHg, respectively, with 95% limits of agreement of -5.0 to 4.5, -4.4 to 5.6, and -4.6 to 6.1 mmHg, respectively. The difference between RTONE(o) and GAT significantly increased with increasing CCT (ρ = 0.004), with a 10% increase in CCT resulting in a 1.8% increase in the difference. CONCLUSIONS: Measurements obtained with the RTONE, either by an ophthalmologist or by the patient, showed an excellent correlation with those provided by applanation tonometry. RTONE generally tends to overestimate IOP compared to GAT readings and displays a dependence on CCT. This study was registered with the DRKS (German Clinical Trials Register; www.germanctr.de ; DRKS00000478).

Canthaxanthin retinopathy: long-term observations.

PURPOSE: To describe the long-term outcome of canthaxanthin retinopathy. METHODS: We identified 13 patients with small golden particles near the macular region among a group of 35 patients with known consumption of canthaxanthin somewhen between 1983 and 1988. One long-term follow-up examination was possible in 5 of 13 cases after 16-24 years. The examinations included determination of visual acuity, the Amsler grid, slit lamp examination, perimetry, electro-oculography, electroretinography, optical coherence tomography and fluorescein angiography. RESULTS: Complete disappearance of the golden particles took approximately 20 years. The patients in our study were asymptomatic and no functional defect related to canthaxanthin could be detected. CONCLUSIONS: Ingestion of canthaxanthin causes no long-term adverse effects.

Fulminant Endogenous Anterior Uveitis due to Listeria monocytogenes.

PURPOSE: To report an unusual case of fulminant anterior uveitis, confirmed as endogenous Listeria monocytogenes infection. SUBJECT: A 67-year-old man with multiple comorbidities acutely developed a severe endogenous anterior uveitis. RESULTS: L. monocytogenes, a ubiquitous Gram-positive bacillus, was directly indicated by culture and PCR. Early and aggressive treatment with intravenous antibiotics likely prevented the endophthalmitis which most cases on record experienced. Our patient regained satisfactory visual acuity. CONCLUSIONS: Prompt antimicrobial therapy is paramount when severe endogenous uveitis develops in a patient with comorbidities, especially with systemic immunosuppression. Treatment solely with corticosteroids should be avoided.

Mitomycin C induces multidrug resistance in glaucoma surgery.

BACKGROUND: Despite the adjuvant use of mitomycin C during trabeculectomy, failures still occur. We investigated whether cultured human Tenon fibroblasts exposed to low-dose mitomycin C developed a multidrug resistance phenotype in vitro, and whether mitomycin C treatment during previous filtration surgery induces P-glycoprotein expression in vivo. METHODS: Cultured human Tenon fibroblasts treated with low-dose 0.01 nM mitomycin C for 2 weeks were subsequently treated with 0.1 to 100 microM mitomycin C in the absence or presence of 4 microM verapamil, and allowed to recover for 24 hours. Low-dose mitomycin C-treated fibroblasts were analysed for P-glycoprotein expression using flow cytometry, immunoblotting, and RT-PCR for mdr-1 mRNA. In addition, fibroblasts were treated with low dose 0.1 nM 5-fluorouracil for 2 weeks and analysed for P-glycoprotein expression using flow cytometry. Expression of P-glycoprotein was analysed in surgically removed Tenon tissue (n = 30) using immunohistochemistry. Of the 30 patients, 20 had a previous trabeculectomy, of which nine had previous adjuvant therapy with mitomycin C during trabeculectomy. RESULTS: Partial resistance to mitomycin C after low-dose mitomycin C pre-treatment was significantly neutralised by the addition of verapamil. Low-dose mitomycin C up-regulated P-glycoprotein expression, but not mdr-1 mRNA expression. 5-Fluorouracil did not induce P-glycoprotein expression. P-glycoprotein expression was detected in all nine patients exposed to mitomycin C during previous trabeculectomies. Only six of 21 specimens from patients not previously exposed to mitomycin C showed faint P-glycoprotein expression. CONCLUSION: The induction of P-glycoprotein by mitomycin C could explain some failures that occur after repeated use of mitomycin C during trabeculectomy. The concomitant use of verapamil or the use of 5-fluorouracil alone could increase the success rate of repeat trabeculectomies.

Synergistic effects of combined cytotoxic and apoptosis-inducing drugs on Tenon's capsule fibroblasts in vitro and in vivo.

BACKGROUND: Highly toxic antimetabolites have gained access to routine clinical use to modulate and reduce the amount of postoperative scarring following glaucomatous filtering procedures. It could be speculated that by combining two different antiproliferative substances with different mechanisms of action total amounts of the substances could be decreased and side effects reduced. METHODS: Twenty-two substances were tested that had antiproliferative effects by acting cytotoxically, inhibiting growth factors, or inducing apoptosis. With combinations of each two substances, cell culture experiments using 3T3 and human Tenon's capsule fibroblasts were performed evaluating cell toxicity, proliferation and migration, the extent of free radicals, and the amount of apoptosis (TUNEL, electron microscopy). The five most potent combinations were used in an animal experiment with rabbits performing filtering procedures. The extent of episcleral scarring was evaluated by histopathology. RESULTS: The results of the various assays revealed consistently strong effects in 5 of the 462 combinations. Of these five combinations, two were highly effective in the rabbit model. Substances with strong effects when applied in combination included staurosporine, mitomycin, and CD95L. CONCLUSIONS: We found synergistic effects in assays that evaluated different aspects of cell function. The amount of scarring in an animal experiment was inhibited to a level comparable with a high single dose of mitomycin. Combination therapy of two antiproliferative acting substances may be a promising concept.

Characteristics of iris and retinal pigment epithelial cells cultured on collagen type I membranes.

PURPOSE: Transplantation of pigment epithelial cells is a promising treatment modality to repair retinal damage in age-related macular degeneration. For this purpose, it is necessary to establish cell culture techniques that allow acquisition of proper functional and morphological characteristics by the cells to be transplanted. METHODS: Primary retinal pigment epithelial (RPE) and iris pigment epithelial (IPE) cells grown to confluence on collagen membranes were examined for morphology, adhesion, proliferation, apoptosis, as well as viability after ex vivo transplantation. RESULTS: Pigment epithelial cells adhere, proliferate, form monolayers, acquire differentiated properties, and remain viable during transplantation to the subretinal space. CONCLUSIONS: Pigment epithelial cells cultured on collagen membranes acquire differentiated characteristics and are amenable to be transplanted as cell monolayers.

Photodynamic therapy for wound-healing modulation in pterygium surgery. A clinical pilot study.

BACKGROUND: This study was performed to evaluate the safety and efficacy of photodynamic therapy with the carboxyfluorescein ester BCECF-AM as an adjunctive treatment procedure for pterygium surgery to reduce the rate of recurrence. METHODS: In this nonrandomized prospective clinical trial, 19 eyes with nasally located primary pterygium were examined. All eyes were treated with the bare sclera surgical technique. Seven eyes received in addition treatment with BCECF-AM solution and blue light. All patients were evaluated at least after 1 day, 1 week, 1 month, 3 months, and 1 year. Postoperative fibrovascular growth from the limbus of at least 1 mm was defined as recurrence. RESULTS: The intraoperative application of BCECF-AM solution did not cause anterior chamber flare or any other significant side effects. The bare sclera surgery rate of recurrence was 0% (zero of 12) after 3 months and 91% (11 of 12) after 1 year. The additional photodynamic therapy treatment had a rate of recurrence of 14.2% (one of seven) after 3 months and 71.4% (five of seven) after 1 year. CONCLUSIONS: The applied PDT technique seems to be a safe procedure but is associated with a high rate of recurrence. In conclusion, the evaluated PDT treatment procedure, at this point, should not be considered. As we found a high rate of recurrence also in the control group, the bare sclera technique is not effective, even in primary pterygia.

Effects of daunorubicin and CD95L on retinal function in superfused vertebrate retina.

Alternative treatments of proliferative vitreoretinopathy (PVR) are needed. The intravitreal application of daunorubicin combined with CD95 ligand (CD95L) could provide a new therapeutic strategy. The effects of this application on bovine retinal function were investigated. Bovine retina preparations were perfused with a standard solution preequilibrated with oxygen. The b-wave and, after the addition of aspartate, the photoreceptor potential P III of the electroretinogram (ERG) were recorded using Ag/AgCl electrodes. Stable ERG amplitudes were recorded, then daunorubicin was added to the solution for 45 minutes, also with the addition of CD95L antibody. Subsequently, the preparation was reperfused with the standard solution for 100 minutes, to allow for recovery. The reduction in b-wave amplitude was reversible and not significantly changed by the addition of 0.25 microg/mL CD95L antibody to 13 microM of daunorubicin. The reduction of the b-wave amplitude was significantly changed and only partly reversible within the recovery time using 40 microM and 80 microM of daunorubicin. The photoreceptor potential P III amplitude was not significantly changed for up to 80 microM of daunorubicin. The ERG showed toxic effects of daunorubicin above a concentration of 13 microM used therapeutically in humans. The combination with CD95L did not increase retinal toxicity. It is, therefore, concluded that daunorubicin may be applied intraocularly, combined with CD95L, without interfering with retinal function.

The influence of Latanoprost 0.005% on aqueous humor flow and outflow facility in glaucoma patients: a double-masked placebo-controlled clinical study.

BACKGROUND: Fluorophotometry and pneumotonography were performed to investigate the effect of Latanoprost 0.005% and Placebo on aqueous humor flow and total outflow facility in human glaucomatous eyes. METHODS: In a randomized double-blind clinical study patients with POAG and OHT receive either Latanoprost 0.005% or placebo once in the evening. Fluorophotometry (Fluorotron Master II, Ocumetrics) and, Pneumotonography, Mentor) was performed in 20 eyes of 10 patients (verum) and 22 eyes of 11 patients (placebo). During a 2 week wash-out period all patients received a systemic antiglaucomatous therapy (Acetazolamide) up to 3 days before baseline measurement. Patients with IOP higher than 28 mmHg at baseline were excluded. Fluorophotometry, tonography and IOP were measured at baseline after 1 and 2 weeks of treatment. Data was analysed by the Student's paired t test. RESULTS: All patients completed the protocol. The IOP significantly decreased (25%) after 1 and 2 weeks of treatment with Latanoprost(p<0.01). Fluorophotometry measurements showed no difference in flow over time in both groups. Although tonographic mean C values in both groups did not show any difference over time, the estimated total outflow facility C (Goldmann) increased significantly (p<0.05) in the verum-treated eyes after 2 weeks. A significant difference of outflow co-efficient correlated to normal pressure (P0/C) was found after 2 weeks of treatment with Latanoprost (p<0.05). CONCLUSIONS: In accordance with the literature we found a mean 25% decrease in IOP after 2 weeks of treatment with Latanoprost 0.005%. The analysis of the flow values in both groups showed no increase or decrease in aqueous humor dynamics as proved in many previous studies. The known effect of Latanoprost increase uveoscleral outflow by remodeling extracellular matrix and widening intermuscular spaces in the ciliary body may not detected by pneumotonography after 2 weeks of treatment. The significant increase in estimated total outflow facility (Goldmann formula) in latanoprost-treated eyes and the decrease of IOP took place at constant flow rates. The increase in conventional outflow facility may indicate trabecular meshwork changes, but it cannot explain the significant decrease in IOP. Furthermore, an additional effect, e.g. uveoscleral outflow, may play the major role as considered in many previous studies.

Latanoprost stimulates secretion of matrix metalloproteinases in tenon fibroblasts both in vitro and in vivo.

PURPOSE: To investigate the presence and the possible role of different matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in Tenon capsule fibroblasts. These enzymes are essential for the control of tissue remodeling in the context of wound repair. This aspect is important to further the understanding of and possibly to influence the scarring process of filtering blebs after glaucoma surgery. METHODS: Untreated and latanoprost-treated human Tenon fibroblasts were examined for the presence of MMPs and TIMPs on the mRNA and protein levels. Assays performed included RT-PCR, real-time RT-PCR, immunocytochemistry, Western blot analysis, flow cytometry, and zymography. To investigate the changes in vivo, conjunctival specimens of rabbits treated with latanoprost eye drops were examined by immunohistochemistry. RESULTS: In all assays, both MMP-3 and TIMP-2 were detected. With the real-time RT-PCR technique, MMP-1, -2, -3, -7, -9, and -14 and TIMP-1 and -2 were detected. An upregulation of MMP-3 and TIMP-2 after latanoprost treatment of the fibroblasts was shown and found to occur on the mRNA and the protein levels. The upregulation of MMP-3 and TIMP-2 was confirmed in vivo. CONCLUSIONS: Tenon fibroblasts contain the ability on the mRNA level to synthesize all enzymes of the MMP and TIMP family that are related to remodeling of the extracellular matrix. The levels of MMP-3 and TIMP-2 increase after treatment with latanoprost. Tenon fibroblasts may be the target cells for attempts to influence the tissue levels of MMPs and TIMPs in the context of conjunctival wound healing after glaucoma surgery.

Characterization of daunorubicin-induced apoptosis in retinal pigment epithelial cells: modulation by CD95L.

PURPOSE: To characterize daunorubicin-induced cell death in cultured human retinal pigment epithelial (RPE) cells and its modulation by CD95 ligand (CD95L). METHODS: In situ DNA end labeling and an ELISA for histone-associated DNA fragments were used to assess apoptosis. CD95 and CD95L expression were examined by immunohistochemistry, flow cytometry, immunoblot, and RT-PCR. Cell death was measured by crystal violet staining. YVAD- and DEVD-amc cleavage was used to measure caspase-1 and -3-like activity. Total RNA and protein synthesis was measured by incorporation level of [(3)H]-leucine and [(3)H]-uridine. RESULTS: RPE cells expressed both CD95 and CD95L, but only CD95 was expressed at the cell surface. Daunorubicin-induced RPE cell apoptosis was associated with enhanced CD95 and CD95L expression. Enhanced CD95L expression was epiphenomenal to the death process, evidenced by the fact that neutralizing CD95L antibodies failed to modulate daunorubicin cytotoxicity. In contrast, the cytotoxic effects of daunorubicin were synergistically enhanced by exogenous CD95L. Synergy appeared to involve enhanced caspase-3-like activity as well as daunorubicin-mediated inhibition of RNA synthesis. CONCLUSIONS: Apoptosis has been shown to be an important factor in the control of specific cell populations. The synergistic activity of an antiproliferative agent, daunorubicin, and a cytokine, CD95L, induces apoptosis in RPE cells. Such approaches provide a means to reduce the concentration of chemotherapeutic agents with a small therapeutic window owing to retinal toxicity, such as daunorubicin, in the adjuvant therapy of proliferative vitreoretinopathy.

Apoptosis-mediating receptor-ligand systems in human retinal pigment epithelial cells.

BACKGROUND: To establish new strategies for the treatment of proliferative vitreoretinopathy (PVR), we investigated new members of a recently discovered apoptosis-inducing receptor-ligand system in human retinal pigment epithelial (RPE) cells. TRAIL (Apo2-L) and Apo3-L are capable of inducing cell death via their receptors Trail-R1 to Trail-R4 and TRAMP. The goal of this study was to prove the existence of these new apoptosis-inducing receptors and ligands in RPE cells. METHODS: Human RPE cells, cultured or prepared directly from the eye, were examined by RT-PCR. Immunohistochemistry of epiretinal membranes of traumatic PVR was performed for the detection of TRAIL and Trail-R1. Protein expression of Trail-R1 was examined in cultured human RPE cells by western blot. Cell death after TRAIL treatment of human RPE cells was measured by crystal violet staining. RESULTS: For RPE cells derived directly from the eye, we detected mRNAs of Trail-R2, Trail-R3, TRAIL, and APO3-L, but not Trail-R1, Trail-R4, and TRAMP. All the examined transcripts were detected in human P0 RPE cells in vitro. Immunohistochemical studies on PVR membranes identified TRAIL and Trail-R1. Western blot confirmed the presence of Trail-R1 in cultured human RPE cells. TRAIL failed to kill RPE cells in vitro, but showed a strong synergistic killing effect when coincubated with protein (cycloheximide) or RNA (actinomycin D) synthesis inhibitor. CONCLUSIONS: We detected a novel apoptosis-inducing receptor-ligand system in RPE cells. An induction of apoptosis as a treatment of PVR seems to be possible. Further investigations are needed including an animal model of PVR.

Characterization of CD95 ligand (CD95L)-induced apoptosis in human tenon fibroblasts.

Toxic side effects of cytotoxic agents such as 5-fluorouracil or mitomycin-C in glaucomatous filtering procedures call for alternative approaches to control fibroblast proliferation. CD95L is a death ligand that triggers apoptosis in susceptible target cells. Apoptosis allows for the safe disposal of cells without damaging the surrounding tissue. The goal of this study was to characterize and to evaluate the CD95L induced cell death in cultured Tenon fibroblasts. Human Tenon fibroblasts were treated with different concentrations of CD95L. For comparison, murine NIH 3T3 fibroblasts were used. Immunohistochemistry and Western blot were used to investigate the CD95 and CD95L expression. Cytotoxicity was measured by crystal violet assay. Apoptosis was investigated using in situ DNA end labelling (TUNEL). DEVD-AMC caspase 3 like activity was measured and caspase 3 processing was studied by immunoblot and the use of the caspase inhibitor DEVD-CHO in cell culture assays. Tenon and NIH 3T3 fibroblasts express CD95 and CD95L. The authors found concentration dependent inhibition of proliferation after CD95L treatment. Tenon fibroblasts, but not NIH 3T3 fibroblasts, show synergy when combined with actinomycin D or cyclohexamide. CD95L treatment did not alter total protein or RNA synthesis. Cell death induced by CD95L was apoptotic and activated caspase 3, as TUNEL positive cells and the active fragment of caspase 3 were found. CD95L induced cell death could be inhibited by the caspase-inhibitor.Here, it is demonstrated that the CD95L induced cell death in cultured human Tenon fibroblasts is apoptotic and possibly mediated by the caspase 3 pathway. These results suggest that it may be possible to use CD95L in glaucomatous filtering procedures. In vivo studies are necessary for further evaluation.