Susanne Wasmuth

Matrix metalloproteinases (MMP-2 and 9) and tissue inhibitors of matrix metalloproteinases (TIMP-1 and 2) during the course of experimental necrotizing herpetic keratitis

To determine the distribution and activities of metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) during the course of experimental herpes simplex virus (HSV) type-1 keratitis, BALB/c mice were corneally infected with 10(5) plaque-forming units (PFU) of HSV-1 (KOS strain) and then observed for the clinical signs of keratitis. Corneas were harvested at days 0, 2, 7 and 14 post-infection (p.i.). MMP-2, MMP-9, MMP-8, TIMP-1 and TIMP-2 were detected by immunohistochemistry and the Western blot technique. The enzymatic activities were analyzed by zymography. Epithelial HSV keratitis was present at day 2 after corneal infection and healed by day 5 p.i. While the expression and activity of MMP-2, MMP-8 and MMP-9 increased in the corneas at day 2 p.i., it was reduced at day 7 p.i. TIMP-1 and -2 were expressed in the corneas before and seven days after infection. Necrotizing stromal keratitis with corneal ulceration and dense polymorphonuclear leukocyte (PMN) infiltration was present at day 14 p.i. This correlated with increased expression of MMP-2, MMP-8 and MMP-9 in the corneas. MMP-8, MMP-9 and MMP-2 staining was particularly intense in the proximity of the ulcers and in areas of PMN infiltration. At day 14 p.i., MMP-2, -8 and -9 activities were upregulated, and TIMP-2 was expressed. These data suggest that MMPs produced by resident corneal cells and PMNs may possibly play a role in early epithelial keratitis and in the ulcerative process in the late phase after corneal HSV-1 infection. The ratio of MMPs to TIMPs may be important for the course of necrotizing HSV keratitis. TIMPs might participate in the repair process.

Amniotic Membrane Transplantation Induces Apoptosis in T Lymphocytes in Murine Corneas with Experimental Herpetic Stromal Keratitis

PURPOSE To investigate the effect of human amniotic membrane transplantation (AMT) on T-cell immune response in murine corneas with herpetic stromal keratitis (HSK). METHODS Herpes simplex virus (HSV)-1-infected BALB/c mice with necrotizing HSK were treated with AMT. CD3(+) cell apoptosis was determined in treated corneas and in vitro by flow cytometric analysis using the annexin V/7-AAD system. The effect of interleukin (IL)-2, cyclosporine, rapamycin, or Fas on T-cell survival was measured. Activation phenotype was measured by (3)H-thymidine uptake and flow cytometry (CD25, CD69, major histocompatibility complex class II). Cytokine/chemokine secretion from amniotic membrane (AM)-treated corneas or draining lymph node cells was measured. The immune-modulating capacity of long-term AMT treatment and adoptive transfer of AM-treated splenocytes was tested. RESULTS After AMT, HSK and corneal inflammatory cell infiltration improved, and T-lymphocyte apoptosis occurred. T-cell apoptosis was also induced in vitro, independently of rIL-2, cyclosporine, rapamycin, or Fas. AMT-treated corneas and cultured lymphocytes had reduced IL-2, IL-10, IL-12, CRG-2, and CCL-2 content. Long-term AMT treatment decreased the proliferative response and type 1 helper T-cell cytokine level in draining lymph node cells. The improvement in HSK did not persist. Delayed-type hypersensitivity or HSV-1-specific cytotoxicity was not altered CONCLUSIONS The results suggest that murine HSK improves after AMT through reduced local T-helper cell immune responses by inducing apoptosis in T lymphocytes, independently of passive apoptosis or activation-induced cell death. AM also reduces local T-helper cytokine and chemokine levels but does not result in immune deviation. Immunologic memory against HSV-1 is not affected by AMT, and long-term protection or tolerance is not induced.

Increased vitronectin production by complement-stimulated human retinal pigment epithelial cells.

PURPOSE A variation in the complement factor H gene was associated with an enhanced risk to develop especially early age-related macular degeneration. Drusen and basal laminar deposits are hallmarks of this AMD manifestation that contain vitronectin as a major component. In this study, the correlation between complement stimulation and vitronectin production of retinal pigment epithelial (RPE) cells was investigated. METHODS ARPE-19 cells, a permanent cell line of human RPE cells, were supplemented with and without human complement competent serum in medium with and without heat inactivated fetal calf serum. The cells were examined in situ for their vitronectin production as an effective inhibitor of alternatively activated complement by immunohistochemistry. Semi-quantitative RT-PCR and Western blots were performed to analyze vitronectin mRNA and protein. RESULTS A strong immunohistochemical staining for vitronectin was observed after complement supplementation. The enhanced production of this complement inactivator by ARPE-19 cells was confirmed by Western blot, whereas the expression analysis revealed unaltered mRNA amounts. CONCLUSIONS A stimulation of RPE cells with complement resulted in an upregulated production of vitronectin. This may support the concept of a protective mechanism, since vitronectin is the major inhibitor of complement activated by the alternative pathway. On the other hand, this increased vitronectin production after complement stimulation may contribute to focal or diffuse deposits in Bruchs membrane, as observed in early AMD.

Amniotic membrane induces peroxisome proliferator-activated receptor-γ positive alternatively activated macrophages.

PURPOSE Amniotic membrane transplantation (AMT) reportedly improves herpetic stromal keratitis (HSK). Here we studied the role of the amniotic membrane (AM) on macrophages. METHODS BALB/c mice with necrotizing HSK received an AMT or tarsorrhaphy (TAR) as control. Apoptosis of F4/80+ cells was determined using the annexinV/7-AAD system. Macrophage invasion was determined using a cornea invasion assay. Cytokine secretion was quantified by ELISA. Arginase activity was measured by bioassay. Expression of nuclear factor (NF)-κB or peroxisome proliferator-activated receptor (PPAR)-γ related proteins was detected by Western blot analysis, and the expression of costimulatory surface molecules or PPAR-γ by flow cytometry. Lipid accumulation was observed by Oil red O and Sudan B staining. RESULTS After AMT apoptotic features of corneal macrophages, but also macrophage invasion increased. IL-6, IL-10, IL-12, TNF-α, and NF-κB content in HSK corneas had decreased with AMT. AMT increased expression of PPAR-γ, arginase 1 and 2, and arginase activity in AM-treated HSK corneas. In vitro, NF-κB, cytokine production, costimulatory molecules (CD80, CD86, CD40), phagocytic capacity, proliferation, viability, and accessory function to herpes simplex virus (HSV)-1 specific draining lymph node (DLN) cells were reduced in bone marrow derived macrophages (BM) cocultured with AM, while CD206, CD204, CD163, and CD68, lipid accumulation in the cytoplasm, PPAR-γ expression, and arginase activity was increased. An increase in viability and proliferation was observed in the presence of AM combined with apoptotic cells, compared with AM alone. CONCLUSIONS Based on these results it can be concluded that the action mechanism of AM is associated with modulation of classically activated macrophages into alternatively activated macrophages or macrophage cell death, probably by engaging lipid metabolism and activating the PPAR-γ pathway, consequently curtailing effector T cell functions. Apoptotic cells induced in the environment with AM support the presence and survival of such macrophages.

Vitreous microRNA levels as diagnostic biomarkers for vitreoretinal lymphoma

To the editor: Primary vitreoretinal lymphoma (PVRL) is often associated with primary central nervous system lymphoma (PCNSL) and is a rare high-grade diffuse large-cell B-cell lymphoma occurring within the vitreous and/or retina.[1][1][⇓][2]-[3][3] Overlapping clinical signs observed in PVRL

Correlation Between Disease Severity and Presence of Ocular Autoantibodies in Juvenile Idiopathic Arthritis- Associated Uveitis

PURPOSE The pathogenesis of juvenile idiopathic arthritis-associated uveitis (JIAU) is undefined. This study intended to analyze the presence of antiocular autoantibodies in serum and their correlation with disease course. METHODS Serum samples from children with JIAU (n = 47); JIA without uveitis (n = 67); idiopathic anterior uveitis (IAU; n = 12); and healthy controls (n = 52) were collected. The binding patterns of serum antibodies to ocular cryosections from swine eyes were analyzed by indirect immunohistochemistry, and were correlated to epidemiological, clinical, and laboratory test results. RESULTS The patient groups differed with respect to their presence of antibody binding to the sections: JIAU (94%), JIA (75%), IAU (75%), and healthy controls (29%) to uveal and/or retinal structures. Serum antibodies of JIAU patients predominantly bound at iris (74%), and ciliary body (79%). Iris/ciliary body positive staining correlated with the presence of uveitis complications (P < 0.005) in JIAU patients, but not with positivity of serum antinuclear antibodies (ANA), rheumatoid factor (RF), or HLA-B27, and was independent from uveitis activity or type of anti-inflammatory therapy. CONCLUSIONS In JIAU patients, antiocular serum antibodies can be detected more frequently than in control groups. Binding patterns to ocular tissue correlate with complicated uveitis course but not with uveitis activity and anti-inflammatory treatment. Antibody binding is not specific for this uveitis entity, and does not correlate with ANA positivity.

Effects of Systemic and Intravitreal TNF-α Inhibition in Experimental Autoimmune Uveoretinitis

PURPOSE To investigate the effect of systemic or local TNF-α inhibition with etanercept on experimental autoimmune uveoretinitis (EAU). METHODS EAU was induced by immunizing B10.RIII mice with IRBPp161-180 or by adoptively transferring uveitogenic splenocytes. Mice received systemic or local treatment with etanercept in the afferent or efferent phase. For systemic treatment, mice were injected intraperitoneally. For local treatment, etanercept was injected intravitreally or subconjunctivally. Control mice received PBS. EAU scores were determined histologically. Splenic cells were assessed for [(3)H]thymidine incorporation. ELISA was performed to measure levels of cytokines produced by splenocytes. Vitreous cavity-associated immune deviation (VCAID) was induced by intravitreally injecting ovalbumin and evaluated by measuring DTH reaction. RESULTS After systemic treatment with etanercept in the afferent phase, EAU disease scores, IRBP-specific cell proliferation, and production of Th1, Th2, and Th17 cytokines were reduced. EAU also improved after intravitreal etanercept treatment in the afferent phase, with unaltered IRBP-specific proliferation, reduced IFN-γ, but increased IL-6 and IL-10 secretion. VCAID induction was impaired after intravitreal etanercept treatment. No amelioration of EAU or reduction in IRBP-specific cell response was found after systemic or intravitreal treatment in the efferent phase or after subconjunctival treatment. After adoptive transfer, etanercept- and PBS-treated recipients showed similar disease severity and antigen-specific proliferation of splenocytes. CONCLUSIONS It can be concluded that TNF-α participates mainly in the immunopathology in the induction phase of EAU. The mechanism of action underlying EAU improvement may be different for local and systemic etanercept treatment.

Complement and UV-irradiated photoreceptor outer segments increase the cytokine secretion by retinal pigment epithelial cells.

PURPOSE Age-related macular degeneration (AMD) is accompanied by increased complement activation, and by lipofuscin accumulation in retinal pigment epithelial (RPE) cells due to incomplete degradation of photoreceptor outer segments (POS). The influence of POS, ultraviolet (UV)-irradiated POS and human complement sera (HCS) on cytokine secretion from RPE cells was therefore examined. METHODS RPE cells were incubated with POS or UV-POS every other day for 1 week. The autofluorescence (AF) was measured photometrically and by flow cytometry. Senescence-associated genes were analyzed by RT-PCR. Internalization and degradation of POS were determined using phagocytosis and degradation assays, and lysosomal function by neutral red uptake. RPE cells in polycarbonate cell culture inserts were incubated apically with POS or UV-POS and afterward basally with HCS. C7-deficient HCS was used as control. The integrity of the cell monolayer was assessed by measuring the transepithelial electrical resistance (TER) and the permeability. Interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1, and vascular endothelial growth factor were quantified by ELISA. RESULTS POS treatment led to an increased AF and senescence marker expression, which were further elevated in response to UV-POS. UV-POS were preferentially accumulated over POS and the lysosomal function was impaired due to UV-POS. HCS intensified the cytokine production compared with controls. POS had no effect, though UV-POS combined with HCS induced a significant increase in all cytokines. CONCLUSIONS RPE cultivation with UV-POS might serve as a model to investigate the accumulation of lipofuscin-like structures. The enhanced cytokine secretion due to UV-POS with HCS may account for an increased susceptibility for lipofuscin-loaded cells to complement, inducing a proinflammatory environment as observed in AMD.

Complement Stimulates Retinal Pigment Epithelial Cells to Undergo Pro-Inflammatory Changes

Background/Aims: We examined the effect of human complement sera (HCS) on retinal pigment epithelial (RPE) cells with respect to pro-inflammatory mediators relevant in early age-related macular degeneration (AMD). Methods: RPE cells were treated with complement-containing HCS or with heat-inactivated (HI) HCS or C7-deficient HCS as controls. Cells were analysed for C5b-9 using immunocytochemistry and flow cytometry. Interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) were quantified by ELISA and RT-PCR. Tumour necrosis factor-a (TNF-a), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), were analysed by Western blotting. The intracellular distribution of nuclear factor (NF)-κB was investigated by immunofluorescence. Results: A concentration-dependent increased staining for C5b-9 but no influence on cell viability was observed after HCS treatment. ELISA and RT-PCR analysis revealed elevated secretion and expression of IL-6, IL-8, and MCP-1. Western blot analysis showed a concentration-dependent increase in ICAM-1, VCAM-1, and TNF-a in response to HCS, and immunofluorescence staining revealed nuclear translocation of NF-κB. Conclusion: This study suggests that complement stimulates NF-κB activation in RPE cells that might further create a pro-inflammatory environment. All these factors together may support early AMD development.

Particle-Mediated Administration of Plasmid DNA on Corneas of BALB/c Mice

Gene gun administration of DNA is an invaluable technique for transfecting tissues with only 1 μg DNA/shot. Here, we describe a transfection technique of healthy corneas of BALB/c mice with a standard gene gun, using a technique that can avoid tissue destruction even when high pressure is used (e.g., 700 psi). The focal transfection of the cornea to improve corneal disease may be an advantage over other transfection methods in order to avoid unwanted bystander transfection in other compartments of the eye or body.