MIGS: therapeutic success of combined Xen Gel Stent implantation with cataract surgery.

PURPOSE: Glaucoma, a common disease in the elderly population, is frequently coexistent with cataract. While the combination of filtration surgery and cataract surgery is a challenging topic with limited success, minimal invasive glaucoma surgery (MIGS), such as Xen Gel Stents, seems to provide promising results. The aim of this study was to investigate the complete and qualified therapeutic success of Xen Gel Stent implantation with (XenPhaco) and without cataract surgery. METHODS: One hundred and eleven open-angle glaucoma eyes underwent implantation of Xen45 Gel Stent (AqueSys, Inc.) with or without cataract operation. Complete therapeutic success was defined as target intraocular pressure (IOP) < 18 mmHg at any time point within 6 months of follow-up without local antiglaucomatous therapy or further surgical interventions. Qualified success was defined as target IOP <18 mmHg with additional 1-2 local antiglaucomatous eye drops. Failure included all cases with the necessity of at least three local antiglaucomatous eye drops or additional glaucoma surgery. RESULTS: Combined implantation of Xen Gel Stent with cataract surgery was performed in 30 eyes and stand-alone Xen Gel Stent implantation was performed in 81 eyes. A complete therapeutic success was achieved in 46.9% of single Xen Gel Stent implantation, whereas 53.3% was reached with combined XenPhaco. Qualified success was seen in 2.5% in the eyes of the single Xen Gel Stent implantation group and in 3.3% of the combined surgery group. Therapeutic failure rate was 49.4% in the stand-alone group vs 46.7% in the combined group. Data were not significantly different for group and subgroup analyses. CONCLUSIONS: Complete and qualified therapeutic success is similar for the combination of Xen Gel Stent implantation with and without cataract surgery in open-angle glaucoma patients. MIGS using Xen Gel Stent can be recommended in situations if glaucoma surgery is indicated besides coexisting cataract.

Common genetic determinants of intraocular pressure and primary open-angle glaucoma.

Intraocular pressure (IOP) is a highly heritable risk factor for primary open-angle glaucoma and is the only target for current glaucoma therapy. The genetic factors which determine IOP are largely unknown. We performed a genome-wide association study for IOP in 11,972 participants from 4 independent population-based studies in The Netherlands. We replicated our findings in 7,482 participants from 4 additional cohorts from the UK, Australia, Canada, and the Wellcome Trust Case-Control Consortium 2/Blue Mountains Eye Study. IOP was significantly associated with rs11656696, located in GAS7 at 17p13.1 (p=1.4×10(-8)), and with rs7555523, located in TMCO1 at 1q24.1 (p=1.6×10(-8)). In a meta-analysis of 4 case-control studies (total N = 1,432 glaucoma cases), both variants also showed evidence for association with glaucoma (p=2.4×10(-2) for rs11656696 and p=9.1×10(-4) for rs7555523). GAS7 and TMCO1 are highly expressed in the ciliary body and trabecular meshwork as well as in the lamina cribrosa, optic nerve, and retina. Both genes functionally interact with known glaucoma disease genes. These data suggest that we have identified two clinically relevant genes involved in IOP regulation.

Human anterior lens capsule serving as a substrate for human trabecular meshwork cells cultivation.

To investigate if human anterior lens capsule is a suitable substrate for the culture of primary human trabecular meshwork (HTM) cells. Trabecular meshwork cells derived from four human donors were seeded on anterior lens capsules that were prepared from the lenses of donor eyes. Cell morphology and viability were examined at 1, 3, 5 and 7 days. Cell viability was measured based on a two-colour fluorescence assay (membrane-impermeable propidium iodide and membrane permeable Hoechst 33342). Immunocytochemistry studied Zonula occludens-1 (ZO-1), vimentin, tissue transglutaminase (tTgase) and Na(+)/K(+)-adenosine triphosphatase (Na(+)/K(+)-ATPase). Morphology of the cultivated cells followed a typical model while their viability was > 95% in all cases. ZO-1 was found at the cell boundaries of the HTM-AC complex. Vimentin was located at the lateral membranes of the HTM cells. Na(+)/K(+)-ATPase was found at the basolateral membrane of the HTM cells. tTgase was also identified. Anterior lens capsule can be considered as a suitable alternative substrate for cultivation of HTM cells and assist the expansion of existing knowledge about glaucoma pathophysiology and therapy.

TGF-ß(2)- and H(2)O(2)-induced biological changes in optic nerve head astrocytes are reduced by the antioxidant alpha-lipoic acid.

BACKGROUND/AIMS: The goal of the present study was to determine whether transforming growth factor-ß(2) (TGF-ß(2))- and oxidative stress-induced cellular changes in cultured human optic nerve head (ONH) astrocytes could be reduced by pretreatment with the antioxidant α-lipoic acid (LA). METHODS: Cultured ONH astrocytes were treated with 1.0 ng/ml TGF-ß(2) for 24 h or 200 µM hydrogen peroxide (H(2)O(2)) for 1 h. Lipid peroxidation was measured by a decrease in cis-parinaric acid fluorescence. Additionally, cells were pretreated with different concentrations of LA before TGF-ß(2) or H(2)O(2) exposure. Expressions of the heat shock protein (Hsp) αB-crystallin and Hsp27, the extracellular matrix (ECM) component fibronectin and the ECM-modulating protein connective tissue growth factor (CTGF) were examined with immunohistochemistry and real-time PCR analysis. RESULTS: Both TGF-ß(2) and H(2)O(2) increased lipid peroxidation. Treatment of astrocytes with TGF-ß(2) and H(2)O(2) upregulated the expression of αB-crystallin, Hsp27, fibronectin and CTGF. Pretreatment with different concentrations of LA reduced the TGF-ß(2)- and H(2)O(2)-stimulated gene expressions. CONCLUSION: We showed that TGF-ß(2)- and H(2)O(2)-stimulated gene expressions could be prevented by pretreatment with the antioxidant LA in cultured human ONH astrocytes. Therefore, it is tempting to speculate that the use of antioxidants could have protective effects in glaucomatous optic neuropathy.

Impact of symptomatic vitreous degeneration on photopic and mesopic contrast thresholds.

CLINICAL RELEVANCE: Contrast thresholds under photopic and mesopic luminance conditions are compromised in subjects with vitreous degeneration. A plausible explanation is needed for the visual discomfort expressed by patients suffering from symptomatic vitreous degeneration. BACKGROUND: The current study investigates the effect of symptomatic vitreous degeneration on photopic and mesopic contrast at high spatial frequencies. METHODS: An age-matched sample of 115 subjects, comprising 30 subjects with symptomatic vitreous floaters (cases) and 85 healthy subjects (controls), was included in this study. Visual acuity and flicker thresholds were measured for all participants. Photopic and mesopic functional contrast thresholds at 10 cycles per degree were measured for all participants to assess the effect of floaters on contrast. Further, to determine the effect of posterior vitreous detachment on contrast, the sample was divided into three groups: cases with posterior vitreous detachment (n = 12); cases without posterior vitreous detachment (n = 18); and controls (n = 85), and their contrast thresholds were compared. RESULTS: Photopic and mesopic contrast thresholds were lower by 37.4% and 27.5%, respectively, when the cases were compared with the controls (p = 0.028 and p < 0.001 for photopic and mesopic contrast thresholds, respectively). Photopic contrast was lower by 64.0% in cases with posterior vitreous detachment compared with controls (p = 0.001). Compared with controls, mesopic contrast was lower in cases with posterior vitreous detachment and in cases without posterior vitreous detachment by 30.3% and 25.6%, respectively (p = 0.014 and p = 0.017 for cases with and without posterior vitreous detachment, respectively). CONCLUSION: : Subjects with vitreous degeneration have diminished photopic and mesopic contrast thresholds compared with controls. This finding highlights the negative impact of vitreous degeneration on the quality of vision.

Dietary Intervention With a Targeted Micronutrient Formulation Reduces the Visual Discomfort Associated With Vitreous Degeneration.

Purpose: To investigate the impact of supplementation with a targeted micronutrient formulation on the visual discomfort associated with vitreous degeneration. Methods: In this clinical trial, 61 patients with symptomatic vitreous floaters were randomized to consume daily, the active supplement consisting of 125 mg L-lysine, 40 mg vitamin C, 26.3 mg Vitis vinifera extract, 5 mg zinc, and 100 mg Citrus aurantium or placebo for 6 months. Change in visual discomfort from floaters, assessed with the Floater Disturbance Questionnaire, was the primary outcome measure. Secondary outcome measures included best-corrected visual acuity, letter contrast sensitivity, photopic functional contrast sensitivity with positive and negative contrast polarity, and quantitative vitreous opacity areas. Results: After supplementation, the active group reported a significant decrease in their visual discomfort from floaters (P < 0.001), whereas the placebo group had no significant change in their visual discomfort (P = 0.416). At 6 months, there was a significant decrease in vitreous opacity areas in the active group (P < 0.001) and an insignificant increase in vitreous opacity areas in the placebo group (P = 0.081). Also, there was a significant improvement in photopic functional contrast sensitivity with positive contrast polarity in the active group after supplementation (P = 0.047). Conclusions: The findings of this study indicate improvements in vision-related quality of life and visual function of patients suffering from vitreous floaters after supplementation with a formulation of antioxidative and antiglycation micronutrients. Notably, these improvements were confirmed by the decrease in vitreous opacity areas in the active group. Translational Relevance: This targeted dietary intervention should be considered to support patients with symptomatic vitreous degeneration.

Vitrectomy does not increase the risk of open-angle glaucoma or ocular hypertension--a 5-year follow-up.

BACKGROUND: The goal of this study was to investigate the development of late onset open-angle glaucoma (OAG) or ocular hypertension after vitrectomy in phakic and pseudophakic eyes. METHODS: In this retrospective case series, the records of 441 patients who had undergone vitrectomy in one eye by a single surgeon were reviewed. The development of OAG or ocular hypertension in the vitrectomized and fellow control eyes was compared. Furthermore, the influence of the lens status (phakic or pseudophakic) on the onset of OAG or ocular hypertension in the vitrectomized and fellow control eyes was analysed. Additionally, the mean intraocular pressure (IOP) and the mean number of antiglaucomatous medications were calculated for both eyes. RESULTS: A mean follow-up period of 79.5 +/- 25.6 months was achieved. There were 19 vitrectomized eyes (4.31%) with postoperative OAG, and 19 vitrectomized eyes (4.31%) with postoperative ocular hypertension. Eleven control eyes (2.49%) had OAG, and 13 control eyes (2.95%) ocular hypertension. There were no statistically significant differences in the development of OAG or ocular hypertension between the vitrectomized and fellow control eyes. Furthermore, the lens status in vitrectomized eyes did not influence the late development of OAG or ocular hypertension. There were no significant differences in the mean IOP and the mean number of antiglaucomatous medications between the two eyes. CONCLUSIONS: Contrary to previous reports, we could not observe an increased incidence of late onset OAG or ocular hypertension after vitrectomy. Similarly, the removal of the lens did not increase the risk of OAG or ocular hypertension in vitrectomized eyes.

Connective tissue growth factor induces extracellular matrix deposition in human trabecular meshwork cells.

The major structural change in the human trabecular meshwork (TM) of eyes with primary open-angle glaucoma (POAG) is an increase in extracellular matrix (ECM) in the juxtacanalicular region of the TM. There is evidence that treatment with TGF-beta2 causes an induction of ECM deposition in cultured human TM cells and that TGF-beta2 is causatively involved in the JCT ECM increase in POAG. In the present study, we investigated the effects of connective tissue growth factor (CTGF) on the biology of cultured human TM cells. CTGF is a downstream mediator of TGF-beta2-signaling, which is expressed at high amounts in the human TM in situ. HEK293 cells were transfected with an eukaryotic expression plasmid containing the coding sequences of human CTGF. Secreted CTGF was isolated and purified by chromatography. Primary human TM cells were incubated for 24 h with CTGF at concentrations of 2.5-100 ng/ml. Following treatment with CTGF, the expression of various ECM components that are expressed in the JCT, matrix metalloproteinases (MMPs) and integrins was investigated by real-time RT-PCR and western blot analyses. In addition, the activity of MMPs was investigated by gelatine zymography. The effect of CTGF silencing on TGF-beta2-induced gene expression was investigated by transfection of immortalized HTM cells with CTGF-specific small interfering (si)RNA before TGF-beta2 treatment. CTGF-treated human TM cells showed an increase in the expression of fibronectin, collagen types I, III, IV and VI, as well as in the integrin subunits aV and beta1. Lower concentrations of CTGF caused an autoinduction of CTGF expression. No effects were observed on the expression and activity of MMP-2, MMP-9 and plasminogen activator inhibitor-1 (PAI-1). Transfection with CTGF-specific siRNA inhibited the TGF-beta2-induced upregulation of CTGF and fibronectin. Our results indicate that treatment of human TM cells with recombinant CTGF causes distinct changes in gene expression and that CTGF is a critical mediator of the effects of TGF-beta2 on ECM synthesis in human TM cells. An intriguing aspect supported by the data of the present work is that the pharmacologic modulation of CTGF might be a useful approach to develop novel therapeutic strategies to prevent or to reverse the structural changes that occur in the TM of eyes with POAG.

Biological effects of native and oxidized low-density lipoproteins in cultured human retinal pigment epithelial cells.

Age-related macular degeneration (AMD) and artherosclerosis share common characteristics in their pathogenesis. In this study, we investigated the effects of lipoproteins like native (n)-LDL, oxidized (ox)-LDL and high-density lipoprotein (HDL) on advanced senescence, extracellular matrix accumulation, cell loss, and transforming growth factor-beta2 (TGF-beta2) expression in cultured human retinal pigment epithelial (RPE) cells. Primary human RPE cells were incubated with 10-100 microg/ml n-LDL, ox-LDL, and HDL for 24h. For determination of advanced senescence, beta-galactosidase staining was used. The induction of fibronectin (Fn), laminin alpha 1 (Laa1), and collagen type IV alpha 2 (Col4a2) mRNA was quantified by real-time PCR. Cell loss was investigated by live dead assay. Expression of TGF-beta2 was analyzed by real-time PCR and ELISA assays. Ox-LDL accelerated dose-dependently the onset of RPE senescence, whereas LDL and HDL had no effect. LDL and ox-LDL led to induced expression of Fn, Laa1 and Col4a2, whereas HDL had no influence. Incubation of RPE cells with 100 microg/ml ox-LDL induced marked cell death compared to untreated control cells. Expression of TGF-beta2 was dose-dependently increased by LDL and ox-LDL. LDL and ox-LDL induced cellular changes in RPE cells in vitro, which may resemble pathogenic events of AMD. These results may provide further information about the effects of LDL and ox-LDL in the human RPE and their potential role in the pathogenesis of AMD.

Hypoxia/reoxygenation induces CTGF and PAI-1 in cultured human retinal pigment epithelium cells.

Early age-related macular degeneration (AMD) is characterized by thickening of Bruch's membrane due to the accumulation of extracellular matrix (ECM). This finding could be related to hypoxia of the retinal pigment epithelium (RPE). In the present study, we investigated the effects of hypoxia and reoxygenation on the expression of connective tissue growth factor (CTGF), plasminogen activator inhibitor-1 (PAI-1), collagen type IV (Col IV) and fibronectin (Fn) in cultured human RPE cells. Cultured human RPE cells were kept for 12-36h under hypoxic conditions (1% O(2)). Reoxygenation was conducted for 24h. Hypoxia-mediated CTGF and PAI-1 expression were analyzed by using immunohistochemistry, Northern and Western blot analysis. Actinomycin D was added to examine whether hypoxia induces the transcription of CTGF and PAI-1 mRNA. Furthermore, cells were transfected with siRNA against hypoxia-inducible factor-1alpha (HIF-1alpha) and kept under hypoxic conditions. The effects of antioxidants on hypoxia/reoxygenation-mediated CTGF and PAI-1 expression were tested by real-time PCR analysis. Production of Col IV and Fn were investigated by real-time PCR and Western blot analysis. Both hypoxia and hypoxia/reoxygenation increased the expression of CTGF, PAI-1, Col IV and Fn. Actinomycin D prevented the new transcription of CTGF and PAI-1 mRNA by hypoxia. Using siRNA against HIF-1alpha, the hypoxia-mediated increase of CTGF and PAI-1 was inhibited. Antioxidants attenuated the reoxygenation-mediated increase of CTGF and PAI-1. The process of hypoxia/reoxygenation in the RPE may lead to an increase of ECM in the RPE and thus may contribute to the accumulation of ECM in Bruch's membrane.

The effect of TGF-beta2 on elastin, type VI collagen, and components of the proteolytic degradation system in human optic nerve astrocytes.

PURPOSE: To investigate the effect of transforming growth factor (TGF)-beta2 on the expression of (1) elastin and type VI collagen (ColVI), (2) extracellular matrix (ECM)-degrading matrix-metalloproteinases (MMPs) and regulators of their activity/activation, and (3) the involvement of connective tissue growth factor (CTGF) in the TGF-beta2-mediated regulations in cultured human type-1A and -1B optic nerve astrocytes. METHODS: Astrocytes were isolated from the optic nerves of 11 donors aged 19 to 62 years without a history of eye disease from the prelaminar (type 1B, five explants) or postlaminar (type 1A, six explants) region. Cultures of passages 3 to 5 were treated with 1 ng/mL recombinant human TGF-beta2 for 72 hours, and regulatory effects on the expression of elastin and the ColVI chains alpha1, alpha2, and alpha3; MMP-1, -2, -3, -7, -9, -12, and -13; tissue inhibitors of MMPs (TIMPs) -1, -2, and -3; plasminogen activator inhibitor 1 (PAI-1); and urokinase and tissue plasminogen activators (uPA, tPA) were initially analyzed by RT-PCR and confirmed and quantified by real-time PCR (rtPCR). The regulation of proteins was studied by Western blot analysis, and MMP-2 activity was assessed by gelatin zymography. The involvement of CTGF was tested by knockdown experiments with CTGF-small interfering (si)RNA. RESULTS: TGF-beta2 increased the expression of elastin (5X[rtPCR]/6X[WB]), ColVIalpha2 (3X/5X), ColVIalpha3 (7X/9X), MMP-2 (2X/2X), TIMP-1/-3 (1.5X/2X), and PAI-1 (8X/4X) compared to untreated controls. tPA was reduced to 0.5X. MMP-1, -3, -7, and -12 and TIMP-2 were expressed but were not responsive to TGF-beta2. MMP-9 and -13 and uPA were marginally expressed and close to the detection threshold. MMP-2 activity was significantly reduced in gelatin zymography. Transfection of CTGF-siRNA blocked TGF-beta2-mediated activation of elastin and ColVI but had no effect on MMP-2 and PAI-1 induction. Type 1A and 1B astrocytes reacted identically. CONCLUSIONS: TGF-beta2 induces expression of elastin and ColVI and thereby could contribute to the increase of type VI collagen fibers in the tissue septae and the elastotic changes typically observed in POAG. With the concurrent activation of TIMP-1 and -3 and PAI-1 and the repression of tPA, TGF-beta2 could negatively regulate the activity and activation of MMPs. This effect could further amplify ECM accumulation and elastosis.

The protective effect of quercetin against oxidative stress in the human RPE in vitro.

PURPOSE: To investigate the possible protective effect of the dietary antioxidant quercetin on retinal pigment epithelial (RPE) cell dysfunction and cellular senescence occurring in age-related macular degeneration (AMD). The major flavonoid quercetin was studied on RPE cells in vitro. METHODS: Cultured human RPE cells were incubated with different concentrations of quercetin for 24 hours. Cells were then treated with 150 to 300 microM hydrogen peroxide for 2 hours. Mitochondrial function was measured by using MTT assay and cell vitality by live-dead staining assay. Intracellular levels of glutathione were determined by using a glutathione assay kit. Apoptosis was quantified by a caspase-3 assay, and cellular senescence was quantified by beta-galactosidase staining. Expression of the senescence-associated transmembrane protein caveolin-1 was investigated by Northern and Western blot analyses. RESULTS: Hydrogen peroxide treatment caused significant decreases in mitochondrial function (52%) and in cell vitality (71%), whereas preincubation with 50 microM quercetin diminished this decrease in a dose-dependent manner. Quercetin treatment did not show any notable effect on intracellular levels of glutathione in either used concentration of quercetin. Hydrogen peroxide-induced activation of caspase-3 was reduced by 50 microM quercetin, from 1.9- to 1.4-fold, compared with untreated control (P < 0.001). Hydrogen peroxide caused a large (>90%) dose-dependent increase in beta-galactosidase-positive cells, whereas in the untreated control only single cells expressed this enzyme (<5%). This increase in cellular senescence was significantly attenuated by quercetin in a dose-dependent manner. The highest attenuation was reached at 50 microM quercetin. Quercetin caused a significant dose-dependent reduction of caveolin-1 mRNA 48 hours after treatment with hydrogen peroxide. After 96 hours of incubation, caveolin-1 protein levels were also reduced. CONCLUSIONS: The data demonstrate that quercetin is able to protect RPE cells from oxidative damage and cellular senescence in vitro in a dose-dependent manner. The authors suggest that this increase in antioxidative capacity is--among other mechanisms, such as the intracellular redox state--also mediated by inhibiting the upregulation of caveolin-1. Downregulation of caveolin-1 may be important for the retinal pigment epithelium to prevent apoptotic cell death in response to cellular stress, a condition implicated in the early pathogenesis of AMD. Therefore, the authors believe that the use of antioxidative dietary flavonoids such as quercetin is a promising approach in the prevention of early AMD.

In vitro safety of intravitreal moxifloxacin for endophthalmitis treatment.

PURPOSE: To investigate the safety of moxifloxacin for intravitreal application in a cell culture model. SETTING: Department of Ophthalmology, Ludwig-Maximilians-Universität, Munich, Germany. METHODS: Primary human retinal pigment epithelium (RPE) cells, ARPE19 cells, and primary optic nerve head astrocyte (ONHA) cells were treated with concentrations of moxifloxacin ranging from 10 to 750 microg/mL. Possible toxic effects and median inhibitory concentration were evaluated after 24 hours as well as under conditions of oxidative stress. After treating the RPE and ONHA cell lines with tumor necrosis factor-alpha (TNF-alpha; 10 microg/mL), lipopolysaccharides (LPS; 20 microg/mL), and interleukin-6 (IL-6; 20 microg/mL), the effects of moxifloxacin on cellular viability under conditions of inflammation were investigated. Toxicity was evaluated by measuring the inhibition of RPE cell proliferation with the tetrazolium dye-reduction assay (MTT; 3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyl tetrazolium bromide). Cell viability was quantified by a microscopic live/dead assay. RESULTS: At concentrations higher than 150 microg/mL, moxifloxacin had adverse effects on primary RPE, ARPE19, and ONHA cell proliferation and viability. Lower concentrations did not affect RPE or ONHA cell proliferation and viability when administered for 24 hours. No significant decrease in proliferation and viability was observed after preincubation with TNF-alpha, LPS, and IL-6 for 24 hours and subsequent treatment with moxifloxacin concentrations of 10 to 150 microg/mL for 24 hours. Hydrogen peroxide exposure did not increase cellular toxicity. CONCLUSIONS: No significant toxicity of moxifloxacin was seen on primary RPE cells, ARPE19 cells, or ONHA cells at concentrations up to 150 microg/mL. Intravitreal use of moxifloxacin up to this concentration may be safe and effective for the treatment of endophthalmitis.

Bone morphogenetic protein-7 is an antagonist of transforming growth factor-beta2 in human trabecular meshwork cells.

PURPOSE: The increase in intraocular pressure in primary open-angle glaucoma (POAG) may involve transforming growth factor (TGF)-beta2 signaling, as TGF-beta2 is found in higher amounts than normal in the aqueous humor of patients with POAG. In vitro, TGF-beta2 causes an accumulation of extracellular matrix (ECM) in the trabecular meshwork (TM) and an increase in TM outflow resistance. The present study was undertaken to determine whether bone morphogenetic protein (BMP)-7 signaling antagonizes the effects of TGF-beta2 on TM cells. METHODS: Cultured TM cells from nine human donors were treated with BMP-7, TGF-beta2, or a combination of both for 24 or 72 hours. The expression of connective tissue growth factor (CTGF); thrombospondin (TSP)-1; fibronectin; collagen types I, III, and IV; plasminogen activator inhibitor (PAI)-1; and matrix metalloproteinase (MMP)-2 were analyzed by immunohistochemistry, real time RT-PCR, Western and Northern blot analysis, and zymography (MMP-2). RESULTS: Treatment with TGF-beta2 induced the expression of CTGF, TSP-1, fibronectin, collagen types IV and VI, and PAI-1. All these effects were inhibited when TGF-beta2 was added in combination with BMP-7, whereas BMP-7 alone had no effects. Treatment with TGF-beta2, BMP-7, or the combination of both had no effect on the expression of collagen types I and III. CONCLUSIONS: BMP-7 strongly antagonizes in vitro the TGF-beta-induced expression of a broad panel of molecules, which would result in an accumulation of TM ECM in situ. As BMP-7 is expressed in the adult human TM in situ, it seems reasonable to assume that it similarly modulates and antagonizes the effects of TGF-beta2 signaling on the tissues of the outflow pathways in vivo. The pharmacological modulation of BMP-7 signaling in the TM might be a promising strategy to treat POAG.

Osteopontin as a serologic marker for metastatic uveal melanoma: results of a pilot study.

PURPOSE: To evaluate the protein osteopontin (OPN) as a potential new marker for screening and detection of metastatic uveal melanoma. DESIGN: Prospective, clinical study. METHODS: Twenty-eight plasma samples of 27 patients with uveal melanoma were analyzed, and the OPN plasma levels were quantified. Eight of these patients showed liver metastasis. As a control, we measured OPN levels in eight healthy, age-matched individuals. RESULTS: The median plasma concentration of OPN in patients with melanoma without metastasis was 46.78 ng/ml (range, 14.5 to 118.67 ng/ml). In contrast, increased median levels of OPN of 170.72 ng/ml (range, 87.37 to 375.54 ng/ml, P <.001) were seen in eight patients with proven metastatic disease. Healthy patients without uveal melanoma showed a median plasma concentration of OPN of 54.6 ng/ml (range, 38.23 to 71.21 ng/ml). CONCLUSION: The protein OPN seems to be a promising tumor marker for detecting metastatic disease in patients with uveal melanoma.

Biochemical and morphological analysis of basement membrane component expression in corneoscleral and cribriform human trabecular meshwork cells.

PURPOSE: To determine whether cells of the cribriform trabecular meshwork (TM) express basement membrane (BM) components similar to corneoscleral TM cells and to determine whether cribriform cells are connected to the elastic tendon net of the TM. METHODS: TM cells of the corneoscleral and the cribriform regions were cultured from 10 eyes of 10 donors, aged 20 to 87 years. Cell types were classified by alpha-smooth muscle actin (smA), desmin, and alphaB-crystallin staining. Expression of collagen type IV (ColIV) chains alpha1 to 6; collagen type VIII (ColVIII) alpha1; laminin subunits alpha1 to 5, beta1 to 3, and gamma1 to 3; and nidogen 1 and 2 was tested in both cell types by semiquantitative RT-PCR (sqPCR). Expression of ColIValpha2, ColVIIIalpha1, laminin beta2, and nidogen 1 was quantified by Northern blot analysis. The response to transforming growth factor (TGF)-beta2 treatment was investigated. Serial tangential and sagittal TM sections of 16 eyes from 10 donors (aged 12-90 years) were used for electron- and immunoelectron microscopy. RESULTS: Both TM cell types expressed ColIV chains alpha1, alpha2, alpha4, alpha5, and alpha6; ColVIII alpha1; laminin subunits alpha3, alpha4, beta1, beta2, beta3, gamma1, and gamma2; and nidogen 1, as determined by Northern blot analysis and sqPCR. ColIV alpha3; laminin subunits alpha1, alpha2, and gamma3; and nidogen 2 were not detectable by PCR. Responses to TGF-beta2 treatment did not differ between cell types. In vivo, all cribriform cells were in contact with ColIV containing BM material and were found to connect to the cribriform elastic network. CONCLUSIONS: Cribriform and corneoscleral TM cells show no differences in expression of BM components and response to TGF-beta2. The direct connection of cribriform cells to the elastic tendon network suggests that they are under mechanical tension. This could explain previous findings of alphaB-crystallin expression in the cribriform region.

Inhibition of human retinal pigment epithelial cell attachment, spreading, and migration by alkylphosphocholines.

PURPOSE: To investigate the effect of alkylphosphocholines (APCs) on human retinal pigment epithelium (RPE) attachment, spreading, migration, and microfilament assembly in vitro. METHODS: Cultured RPE cells of five human donors were treated with one of four APCs (C18:1-PC, C20:1-PC, C21:1-PC, or C22:1-PC) in the presence of fetal calf serum. Cell viability was tested by the trypan blue exclusion assay. Attachment was assessed after a 2-hour incubation of RPE cells on coated 96-well-plates and subsequent MTT testing. Cellular spreading is characterized by cytoplasmic halo formation and was quantified by counting four separate fields of RPE cells allowed to spread on coated 24-well plates for 4 hours. Migration was measured by a modification of the Boyden chamber method in microchemotaxis chambers with polycarbonated filters. Microfilament assembly was assessed by immunofluorescence analysis after incubation with rhodamine-phalloidin. RESULTS: All four APCs inhibited RPE cell attachment by more than 70% of their IC50 (C18:1-PC: 30 microM; C20:1-PC: 10 microM; C21:1-PC: 10 microM; and C22:1-PC: 10 microM). Also, APCs inhibited RPE cell spreading by more than 80% and migration by more than 90% at similar concentrations. Trypan blue staining revealed a toxicity within control limits within the concentration interval tested. Microfilament organization was significantly disturbed after incubation of RPE cells with one of the four APCs close to its IC50. CONCLUSIONS: APCs inhibit RPE cell attachment and spreading in vitro at nontoxic concentrations. As a possible mechanism of action, APCs disturb microfilament assembly, since they are known to interfere with protein kinase C (PKC) function. This could represent a novel method of preventing even early stages of proliferative vitreoretinal diseases like proliferative vitreoretinopathy (PVR).

Galectin-1 influences migration of retinal pigment epithelial cells.

PURPOSE: To determine whether the beta-galactoside-binding matricellular protein Gal-1 is expressed in human specimens of proliferative vitreoretinopathy (PVR) and to evaluate its influence on RPE migration. METHODS: RT-PCR was used to detect Gal-1-specific transcripts in PVR membranes, and the expression pattern of Gal-1 was examined by immunohistochemistry. Expression of Gal-1 in native, low- and high-density cultured RPE cells was determined by Western blot analysis. Cultured human RPE cells were treated with bFGF, TGF-beta2, PDGF-BB, or HGF. The dose-response of Gal-1 mRNA expression was measured by by real-time quantitative RT-PCR and Northern blot analysis. Induction of Gal-1 protein was confirmed by Western blot analysis. To study the effect of Gal-1 on RPE migration in vitro, Gal-1 expression was silenced by RNA interference. beta-Lactose was used to saturate extracellular galectins. RPE cell migration was assessed by a modified Boyden chamber assay, with HGF as the chemoattractant. RESULTS: Gal-1 mRNA expression was present in human specimens of PVR membranes, and staining for Gal-1 was distributed throughout the extracellular matrix (ECM) of PVR membranes. Colocalization was found with laminin and fibronectin and cells of epithelial origin. Western blot analysis revealed greater baseline expression levels in low-density cultured RPE cells than in native and high-density cultured RPE cells. Treatment with HGF caused a dose-dependent increase in Gal-1 expression. Low expression levels of Gal-1 correlated with a reduction of RPE migration to 14% of control. beta-Lactose inhibited HGF-induced RPE cell migration to 23% of control. CONCLUSIONS: Gal-1 is present in the extracellular matrix of PVR membranes and may be derived from dedifferentiated RPE cells. The expression level of Gal-1 appears to be related to a migratory RPE phenotype and stimulation by HGF, both conditions implicated in the pathogenesis of early PVR. Furthermore, HGF-induced RPE migration may be dependent, at least in part, on Gal-1- and beta-galactoside-dependent mechanisms.

Potential role of tissue transglutaminase in glaucoma filtering surgery.

PURPOSE: Scarring of the filtering bleb site is the main cause of failure in glaucoma filtration surgery. In the present study, the role of tissue transglutaminase (tTgase) in the accumulation of extracellular matrix (ECM) proteins in these scars was investigated. Transglutaminases are enzymes capable of cross-linking ECM proteins to proteolysis-resistant complexes. METHODS: Expression of tTgase, its reaction product epsilon-(gamma-glutamyl)-lysine, and fibronectin and their colocalization were investigated immunohistochemically in failed blebs and in an in vitro trabeculectomy model. Failed blebs were analyzed by RT-PCR for the presence of tTgase mRNA. Human Tenon fibroblasts (HTFs) were treated with transforming growth factor-beta2 (TGF-beta2). The effect was studied with immunohistochemistry, Northern blot analysis, and Western blot analysis. tTgase activity was assayed by incorporation of biotinylated cadaverine into fibronectin. RESULTS: Expression of tTgase and epsilon-(gamma-glutamyl)-lysine was present in all failed blebs. Staining was most prominent at the rim of the Tenon cyst. In the in vitro trabeculectomy model, tTgase and epsilon-(gamma-glutamyl)-lysine were barely present at the incision side of the flap but were perspicuously increased by TGF-beta2 treatment. Enzyme and its reaction product were colocalized with fibronectin. Cultured HTFs contained a basal level of tTgase mRNA. After treatment with TGF-beta2, expression and activity of tTgase significantly increased. CONCLUSIONS: The findings demonstrated that tTgase is present and functionally active in failed blebs. Expression and activity of tTgase appeared to be stimulated by TGF-beta2, a growth factor known to be increased in primary open angle glaucoma. Intervention at this pathway might open a new approach to prevent scarring after glaucoma filtration surgery.

Immunohistochemical findings after LASIK confirm in vitro LASIK model.

PURPOSE: To compare immunohistochemical findings in human donor corneas after successful laser in situ keratomileusis (LASIK) without clinical complications with a recently established human LASIK in vitro model. METHODS: Donor corneas with prior LASIK treatment were investigated. Cryostat sections were stained immunohistochemically for collagen types I, III, and VI and laminin and fibronectin. RESULTS: With light microscopy, the interface of the LASIK flap could hardly be detected. In all samples, fibronectin was consistently detected along the entire extent of the surgical wound. In contrast, collagen type III and laminin only stained the superficial portion of the LASIK incision site. Staining for collagen types I and VI showed no changes after LASIK. CONCLUSION: Histologic findings in donor corneas with prior LASIK treatment confirm histologic observations in a recently introduced human organ culture LASIK model. This strengthens the reliability of the latter LASIK model for further studies concerning wound healing after LASIK surgery.