Soluble B-cell maturation antigen in lacrimal fluid as a potential biomarker and mediator of keratopathy in multiple myeloma

Belantamab mafodotin (belantamab) is a first-in-class anti-BCMA antibody-drug conjugate approved for the treatment of triple-class refractory multiple myeloma. It provides a unique therapeutic option for patients ineligible for CAR-T and bispecific antibody therapy, and/or patients progressing on anti-CD38 treatment where CAR-T and bispecifics might be kept in reserve. Wider use of the drug can be challenged by its distinct ocular side effect profile, including corneal microcysts and keratopathy. While dose reduction has been the most effective way to reduce these toxicities, the underlying mechanism of this BCMA off-target effect remains to be characterized. In this study, we provide the first evidence for soluble BCMA (sBCMA) in lacrimal fluid and report on its correlation with tumor burden in myeloma patients. We confirm that corneal cells do not express BCMA, and show that sBCMA-belantamab complexes may rather be internalized by corneal epithelial cells through receptor-ligand independent pinocytosis. Using an hTcEpi corneal cell-line model, we show that the pinocytosis inhibitor EIPA significantly reduces belantamab-specific cell killing. As a proof of concept, we provide detailed patient profiles demonstrating that, after belantamab-induced cell killing, sBCMA is released into circulation, followed by a delayed increase of sBCMA in the tear fluid and subsequent onset of keratopathy. Based on the proposed mechanism, pinocytosis-induced keratopathy can be prevented by lowering the entry of sBCMA into the lacrimal fluid. Future therapeutic concepts may therefore consist of belantamab-free debulking therapy prior to belantamab consolidation and/or concomitant use of gamma-secretase inhibition as currently evaluated for belantamab and nirogacestat in ongoing studies.

Polyhexanide based contact lens storage fluids frequently exhibit insufficient antifungal activity against Fusarium species

PURPOSE

Fusarium keratitis is a severe infection of the anterior eye, frequently leading to keratoplasty or surgical removal of the affected eye. A major risk factor for infection is the use of contact lenses. Inadequate hygiene precautions and mold-growth permissive storage fluids are important risk factors for fungal keratitis. The aim of this study was to comparatively analyze contact lens storage fluids disinfection efficacy against Fusarium species.

METHODS

Eleven commercially available storage fluids were tested. The storage fluids were classified according to their active ingredients myristamidopropyldimethylamine (Aldox), polyhexanide and hydrogen peroxide. Efficacy was tested against isolates belonging to the Fusarium solani and Fusarium oxysporum species complexes as the most common agents of mould keratitis. Tests were carried out based on DIN EN ISO 14729.

RESULTS

All Aldox and hydrogen peroxide (H2O2) based fluids were effective against Fusarium spp., while the majority of polyhexanide based storage fluids showed only limited or no antifungal effects. Efficacy of polyhexanide could be restored by the addition of the pH-regulating agent tromethamine - an additive component in one commercially available product.

CONCLUSIONS

In summary, the use of Aldox- or hydrogen peroxide-based storage fluids may reduce the risk of Fusarium keratitis, while polyhexanide-based agents largely lack efficacy against Fusarium.

[Continuous Optimisation of Experimental Models - an Example from Glaucoma Research]

BACKGROUND

There is a great demand for suitable models to test novel surgical and therapeutic approaches in glaucoma therapy. To address this need and to provide further alternatives to in vivo animal models, we aimed at modifying an established in vitro porcine eye perfusion model.

METHODS

Two weaknesses of the previously established porcine anterior segment model include media leakage during perfusion and setup disintegration due to mechanical instability. To overcome these, we slightly modified the previously used custom-made perfusion dishes and incorporated new components into the model setup. To prevent fluid leakage, we secured the anterior segments more firmly to the perfusion trays using a compression ring, steel screws, and nuts. Customised mounts were used to stabilise the perfusion dish and pressure transducer as a single unit. The mounts were made of polylactide (PLA) and printed using a 3D printer.

RESULTS

The use of steel screws and nuts allowed tighter clamping of the anterior segments and prevented medium leakage. Our PLA custom mounts stabilised the entire assembly and facilitated handling during experiments and improved comparability between tested eyes. They also prevented accidental detachment of the pressure transducers, which resulted in more stable pressure curves. Our PLA mounts tolerated incubation temperatures of up to 37 °C and disinfection with enzymatic detergents and 70% ethanol without showing signs of deformation or degradation after four months of regular usage.

CONCLUSION

Modifications introduced to an established in vitro perfusion model improved its efficacy and reproducibility. Our adjusted model is an example of how many models can be optimised through critical analysis, thereby saving resources and providing reliable results in the long run.

Full thickness 3D in vitro conjunctiva model enables goblet cell differentiation

In vitro culture and generation of highly specialized goblet cells is still a major challenge in conjunctival 3D in vitro equivalents. A model comprising all physiological factors, including mucus-secreting goblet cells has the potential to act as a new platform for studies on conjunctival diseases. We isolated primary conjunctival epithelial cells and fibroblasts from human biopsies. 3D models were generated from either epithelial layers or a combination of those with a connective tissue equivalent. Epithelial models were investigated for marker expression and barrier function. Full-thickness models were analyzed for goblet cell morphology and marker expression via immunofluorescence and quantitative real-time PCR. Simple epithelial models cultured at the air-liquid interface showed stratified multi-layer epithelia with pathologic keratinization and without goblet cell formation. The combination with a connective tissue equivalent to generate a full-thickness model led to the formation of a non-keratinized stratified multi-layer epithelium and induced goblet cell differentiation. In our model, a high resemblance to natural conjunctiva was achieved by the combination of conjunctival epithelial cells with fibroblasts embedded in a collagen-hydrogel as connective tissue equivalent. In the future, our conjunctival in vitro equivalent enables the investigation of goblet cell differentiation, conjunctival pathologies as well as drug testing.

Current practice in the treatment of epithelial and melanocytic tumors with Interferon-alpha 2b: a survey among tertiary eye centers in Germany

Purpose: To evaluate the standard of care, in particular the use of topical or subconjunctival Interferon-α2b, in treating ocular surface squamous neoplasia or melanocytic tumors among tertiary eye centers in Germany. Methods: A survey containing 14 questions was sent to 43 tertiary eye centers in Germany. The questions addressed the surgical and medical management of ocular surface squamous neoplasia and melanocytic tumors (primary acquired melanosis and malignant melanoma) as well as the clinical experiences and difficulties in prescribing off-label Interferon-α2b eye drops and subconjunctival injections. Results: Twenty-four tertiary eye centers responded to the survey. Eighty-three percent of centers have used Interferon-α2b in their clinical practice and 25% prescribed it as the first-line cytostatic agent following surgical excision of ocular surface squamous neoplasia, while 10% would do so for melanocytic tumors. Correspondingly, the majority of respondents selected Mitomycin C as their first-line agent. Side effects were uncommon with topical Interferon-α2b eye drops, but were more frequently reported after subconjunctival Interferon-α2b injections. In total, eight centers had experience with Interferon-α2b injections. The most significant obstacles perceived by ophthalmologists when prescribing Interferon-α2b were its high cost and the reimbursement thereof. Conclusion: Off-label Mitomycin C was the preferred adjuvant therapy for epithelial and melanocytic tumors, with Interferon-α2b being the standard second-line option. Interferon-α2b has predominantly been used to treat ocular surface squamous neoplasia and, to a lesser extent, melanocytic tumors at German tertiary eye centers. Following its market withdrawal, supply shortages of Interferon-α2b are likely to have a profound impact on patient care and their quality of life. Ziel: Evaluation des Therapiestandards, insbesondere der Verwendung von topischem oder subkonjunktivalem Interferon-α2b, bei der Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche oder melanozytären Tumoren der Augenoberfläche in tertiären Augenzentren in Deutschland. Methoden: Eine Umfrage mit 14 Fragen wurde an 43 tertiäre Augenzentren in Deutschland verschickt. Die Fragen befassten sich mit der chirurgischen und medizinischen Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche und melanozytären Tumoren (primär erworbene Melanose und malignes Melanom) sowie den klinischen Erfahrungen und Schwierigkeiten bei der Verschreibung von Off-Label Interferon-α2b Augentropfen und subkonjunktivalen Injektionen. Ergebnisse: 24 tertiäre Augenzentren nahmen an der Umfrage teil. 83% der Zentren hatten Interferon-α2b eingesetzt und 25 % verschrieben es als First-Line-Therapie nach chirurgischer Entfernung von Neoplasien der plattenepithelialen, okulären Oberfläche, wohingegen 10 % dies bei melanozytären Tumoren angewendet hätten. Dementsprechend wählte die Mehrheit der Befragten Mitomycin C als Mittel der ersten Wahl aus. Nebenwirkungen waren bei topischen Interferon-α2b Augentropfen selten, wurden aber häufiger nach subkonjunktivalen Interferon-α2b-Injektionen gemeldet. Insgesamt hatten acht Zentren Erfahrungen mit Interferon-α2b-Injektionen. Die größten Hürden, die Augenärzte bei der Verschreibung von Interferon-α2b hinderten waren die hohen Kosten und deren Übernahme durch die Krankenkassen. Schlussfolgerung: Off-label Mitomycin C war die bevorzugte adjuvante Therapie für epitheliale und melanozytäre Tumoren, während Interferon-α2b Standardoption für eine Zweitlinientherapie war. Interferon-α2b wurde in deutschen, tertiären Augenzentren vorwiegend zur Behandlung von Neoplasien der plattenepithelialen, okulären Oberfläche und in geringerem Maße von melanozytären Tumoren eingesetzt. Nach der Marktrücknahme von Interferon-α2b werden Lieferengpässe wahrscheinlich beträchtliche Auswirkungen auf die Patientenversorgung und ihre Lebensqualität haben.

Morphological Macular Changes Under Brolucizumab Treatment for Neovascular Age-Related Macular Degeneration Refractory to Previous Anti-VEGF Treatment Compared with Treatment-Naive Eyes

Purpose

To evaluate the morphological macular changes and fluid dynamics under brolucizumab treatment in eyes refractory to previous anti-vascular endothelial growth factor (anti-VEGF) treatment for neovascular age-related macular degeneration (nAMD) compared with treatment-naive eyes.

Methods

Retrospective study of all eyes treated with brolucizumab for nAMD between 2020 and 2021 with a fixed injection regimen and one year follow-up. Treatment-naive eyes (TN) were compared with eyes refractory to previous treatment with bevacizumab, ranibizumab, or aflibercept (RT). The primary outcome measure was change of best-corrected visual acuity (BCVA). Secondary outcome measures included foveal central thickness (FCT), presence of intra- or subretinal fluid (IRF, SRF) and presence of pigment epithelial detachment (PED) at any time point during treatment in both groups.

Results

Seventeen TN eyes and 17 RT eyes were included. Mean BCVA and mean FCT in TN eyes had significantly improved after 3 months and continued to improve during treatment (p<0.05 and p=0.001, respectively). In RT eyes, mean BCVA did not change significantly while mean FCT had improved after 3 months of treatment and remained stable thereafter. SRF or PED were more frequent in RT eyes compared with TN eyes (p=0.003 and p=0.005, respectively).

Conclusion

After 3 months of treatment, the BCVA increased significantly only in TN eyes, while the FCT was significantly reduced in both groups. IRF appears to be similarly seen in both groups after the loading phase; however, SRF and PED appear to be more frequent in the RT eyes compared with TN eyes.

Long-Term Outcome of Corneal Collagen Crosslinking with Riboflavin and UV-A Irradiation for Keratoconus

PURPOSE

To evaluate long-term outcomes of corneal collagen crosslinking (CXL) using riboflavin and UV-A irradiation and to determine when to repeat CXL.

METHODS

In this retrospective consecutive interventional case series 131 eyes of 131 patients (95 male, 36 female, mean age 29.7 ± 11.4 years) between 2006 and 2016 received standard CXL (Dresden protocol, epithelium-off) for progressive keratoconus. Corrected distance visual acuity (CDVA) and corneal tomography (K₁, K₂, K_max) were repeatedly recorded 1 year (n = 103 eyes) to 10 years (n = 44) postoperatively. Only one eye per patient was included. Paired t-test or Wilcoxon matched-pairs signed rank test was used for parametric and nonparametric data, respectively.

RESULTS

1-3 years preoperatively, median K₂ significantly increased by 1.1 D (p < 0.001). Postoperatively, median K₂ increased by 0.1 D after 1 year, then decreased over the remaining postoperative period by 0.85 D (p = 0.021). K_max fluctuated without significant change. Median apical corneal thickness decreased by 16 µm (p = 0.012) after 5 years and then returned to preoperative values. Mean CDVA showed a significant improvement (decrease in logMAR 0.08 after 10 years, p = 0.010). CXL non-responders, defined by a postoperative increase in K_max>2 D, increased from 16% after 5 to 33% after 10 years. Risk factors for non-response were young age, high astigmatism (>4.3 D), thin cornea (<480 µm), poor initial visual acuity (CDVA ≥0.3 D), and atopic dermatitis. 4 eyes were re-treated 3-4 years after first CXL without complications and keratoconus stabilized thereafter.

CONCLUSIONS

CXL can slow or stop keratoconus progression. However, as the number of responders declines after 5 years, especially patients with risk factors may require re-treatment.

Eye Infections Caused by Filamentous Fungi: Spectrum and Antifungal Susceptibility of the Prevailing Agents in Germany

Fungal eye infections can lead to loss of vision and blindness. The disease is most prevalent in the tropics, although case numbers in moderate climates are increasing as well. This study aimed to determine the dominating filamentous fungi causing eye infections in Germany and their antifungal susceptibility profiles in order to improve treatment, including cases with unidentified pathogenic fungi. As such, we studied all filamentous fungi isolated from the eye or associated materials that were sent to the NRZMyk between 2014 and 2020. All strains were molecularly identified and antifungal susceptibility testing according to the EUCAST protocol was performed for common species. In total, 242 strains of 66 species were received. Fusarium was the dominating genus, followed by Aspergillus, Purpureocillium, Alternaria, and Scedosporium. The most prevalent species in eye samples were Fusarium petroliphilum, F. keratoplasticum, and F. solani of the Fusarium solani species complex. The spectrum of species comprises less susceptible taxa for amphotericin B, natamycin, and azoles, including voriconazole. Natamycin is effective for most species but not for Aspergillus flavus or Purpureocillium spp. Some strains of F. solani show MICs higher than 16 mg/L. Our data underline the importance of species identification for correct treatment.

Diagnosing small fiber neuropathy in clinical practice: a deep phenotyping study

Background and aims

Small fiber neuropathy (SFN) is increasingly suspected in patients with pain of uncertain origin, and making the diagnosis remains a challenge lacking a diagnostic gold standard.

Methods

In this case-control study, we prospectively recruited 86 patients with a medical history and clinical phenotype suggestive of SFN. Patients underwent neurological examination, quantitative sensory testing (QST), and distal and proximal skin punch biopsy, and were tested for pain-associated gene loci. Fifty-five of these patients additionally underwent pain-related evoked potentials (PREP), corneal confocal microscopy (CCM), and a quantitative sudomotor axon reflex test (QSART).

Results

Abnormal distal intraepidermal nerve fiber density (IENFD) (60/86, 70%) and neurological examination (53/86, 62%) most frequently reflected small fiber disease. Adding CCM and/or PREP further increased the number of patients with small fiber impairment to 47/55 (85%). Genetic testing revealed potentially pathogenic gene variants in 14/86 (16%) index patients. QST, QSART, and proximal IENFD were of lower impact.

Conclusion

We propose to diagnose SFN primarily based on the results of neurological examination and distal IENFD, with more detailed phenotyping in specialized centers.

The Development and Status of Eye Banking with Special Focus on the Commitment of LIONS Clubs

BACKGROUND

Ever since the first successful keratoplasty in 1905, there has been a need to store corneas for transplantation. R. Townley Paton founded the first eye bank in New York in 1944. With Helen Keller's call in 1925 for LIONS to "constitute themselves Knights of the Blind in the crusade against darkness", LIONS Clubs International has become involved in the establishment of eye banks worldwide. This paper presents the development of eye banking in general and with special attention to the support offered by LIONS Clubs.

METHODS

Selective literature search through PubMed, Google Scholar and Google in close cooperation with the LIONS Eye Banks already established in Germany, LIONS Clubs International (USA) and the Julius Hirschberg Society (Austria). Analysis focused on the founding processes of 6 German eye banks and their current services.

RESULTS

Filatov was the first to keep donor eyes in a cool, moist container for a few days. In 1973, Summerlin et al described the technique of organ culture for donor corneas, and McCarey & Kaufman described a liquid storage medium in 1974. LIONS Clubs International and their organisational structure first supported an eye bank in the US in 1952, outside America in Hong Kong in 1962 and in Germany in 1969. Funding is provided across all levels of LIONS as network support and material resources. In general, staff funding is not provided. Of the 88 eye banks operating worldwide today, 44 are called LIONS Eye Banks. 6 of the current 26 eye banks in Germany are operating under LIONS sponsorship and run by departments of ophthalmology at university medical centres. Although the number of transplants has increased in recent years due to new surgical techniques, the number of patients waiting for donor tissue is also growing as a result of the broadening indication.

CONCLUSIONS

Even today, the availability of donor corneas limits patient care. Eye banks help to meet the need for donor corneas. However, the techniques and technical equipment of eye banks must undergo continuous improvement. The local, national and international network of LIONS Clubs can assist in establishing these in order to facilitate legal requirements and structural developments. This support frequently lasts for many years, often triggers additional public commitment and is thus also a supporting element for the future development of eye banking in Germany.

First case of Kluyveromyces marxianus (Candida kefyr) late onset keratitis after lamellar endothelial corneal graft

We present a case of Kluyveromyces marxianus keratitis nine months after Descement's membrane endothelial keratoplasty (DMEK) in a patient with Fuchs endothelial disease. Endothelial scraping revealed this rare yeast infection at the interface between graft and host cornea. Immediate antifungal treatment with intracameral and corneal intrastromal injections of voriconazole and amphotericin B remained unsuccessful, requiring penetrating keratoplasty. This case highlights the challenging management of keratomycosis in patients with endothelial grafts.

[Correlation of in vivo/ex vivo imaging of the posterior eye segment]

BACKGROUND

For an understanding of the pathology of retinal diseases, direct comparisons of high-resolution in vivo retinal imaging and ex vivo histological preparations are desirable.

MATERIAL AND METHODS

Multimodal in vivo and ex vivo imaging of a human donor eye with secondary alterations showing atrophic retina due to central retinal arterial occlusion. The subsequent correlation with the histological examination was carried out on identical tissue localizations.

RESULTS

Appropriate custom-built retinal imaging devices facilitate in vivo and ex vivo correlations and the examination of human eye tissue and acquisition of retinal images, e.g. SD-OCT. The precise alignment of the tissue enables a histological analysis on identical sites.

CONCLUSION

The direct correlation of clinical in vivo imaging with ex vivo imaging including histopathology can further enhance our understanding in the pathogenesis of retinal diseases; however, the proposed method is currently limited due to restricted availability of human donor tissue.

SARS-CoV-2: Impact on, Risk Assessment and Countermeasures in German Eye Banks

INTRODUCTION

Since the beginning of the COVID-19 pandemic there has been some debate regarding the risk of transmission through tissue transplantation and tissue banking processes.

AIM OF THE STUDY

To analyze the changes that SARS-CoV-2 has caused regarding the harvesting of corneal donor tissue and eye bank activities in Germany.

METHODS

A questionnaire was provided to 26 eye banks in Germany, consisting of questions about adaptations made in the screening of potential donors and the harvesting of corneal tissue following the pandemic spread of SARS-CoV-2.

RESULTS

Eighteen eye banks actively reduced recruitment of donors and two banks ceased all activity. Additional diagnostic screening was performed in eight banks, using conjunctival swabs and/or nasopharyngeal swabs. In six eye banks, additional protective measures, such as FFP2 masks and/or facial shields, were implemented. Overall, a mean reduction in the number of obtained donor tissues of 17% was observed.

DISCUSSION

Conjunctival and/or nasopharyngeal swabs of donors have been implemented by a minority. Reasons for not performing additional tests may be moderate sensitivity and lack of validation for postmortem use of RT-PCR testing. Also, the hazard of SARS-CoV-2 entering the corneal donor pool with subsequent transmission might be perceived as theoretical. Face shields provide a sufficient barrier against splash and splatter contamination but may be insufficient against aerosols. Additional face masks would provide support against aerosols, but it remains debatable if corneal harvesting can be considered an aerosol-producing procedure. In the future we expect to see changes in current guidelines because of a surge in scientific activities to improve our understanding of the risks involved with cornea donation in the COVID-19 pandemic, and because current practice may reduce the availability of donor corneas due to new exclusion criteria while the demand remains unchanged.

Reduced association between dendritic cells and corneal sub-basal nerve fibers in patients with fibromyalgia syndrome

In our study, we aimed at investigating corneal langerhans cells (LC) in patients with fibromyalgia syndrome (FMS) and small fiber neuropathy (SFN) as potential contributors to corneal small fiber pathology. We enrolled women with FMS (n = 134) and SFN (n = 41) who underwent neurological examination, neurophysiology, prostaglandin analysis in tear fluid, and corneal confocal microscopy (CCM). Data were compared with those of 60 age-matched female controls. After screening for dry eye disease, corneal LC were counted and sub-classified as dendritic (dLC) and non-dendritic (ndLC) cells with or without nerve fiber association. We further analyzed corneal nerve fiber density (CNFD), length (CNFL), and branch density (CNBD). Neurological examination indicated deficits of small fiber function in patients with SFN. Nerve conduction studies were normal in all participants. Dry eye disease was more prevalent in FMS (17%) and SFN (28%) patients than in controls (5%). Tear fluid prostaglandin levels did not differ between FMS patients and controls. While corneal LC density in FMS and SFN patients was not different from controls, there were fewer dLC in association with nerve fibers in FMS and SFN patients than in controls (P < .01 each). Compared to controls, CNFL was lower in FMS and SFN patients (P < .05 each), CNFD was lower only in FMS patients (P < .05), and CNBD was lower only in SFN patients (P < .001). There was no difference in any CCM parameter between patients with and without dry eyes. Our data indicate changes in corneal innervation and LC distribution in FMS and SFN, potentially based on altered LC signaling.

Modulation of Contact Inhibition by ZO-1/ZONAB Gene Transfer-A New Strategy to Increase the Endothelial Cell Density of Corneal Grafts

Purpose

Endothelial cell density (ECD) is the principal factor determining the success of corneal transplants. Here we explored a strategy to increase corneal ECD in human explants via modulation of the ZO-1/ZONAB pathway. In multiple cell types, ZO-1 maintains G1 cell cycle arrest via cytoplasmic sequestration of the mitosis-inducing transcription factor ZONAB. In this study, we assessed the effects of lentiviral vector-mediated downregulation of ZO-1 or overexpression of ZONAB upon ECD and the integrity of the endothelial monolayer.

Methods

HIV-based lentiviral vectors were used to deliver either constitutively expressed ZONAB (LNT-ZONAB), or a small hairpin RNA targeting ZO-1 (LNT-shZO1). Human corneal specimens were bisected and each half was exposed to either treatment or control vector. After 1 week in ex vivo culture, effects were assessed by quantitative RT-PCR, immunohistochemistry, and ECD assessment.

Results

LNT-shZO1 achieved an ∼45% knockdown of ZO-1 mRNA in corneal endothelial cells cultured ex vivo, reduced ZO-1 staining, and did not affect morphologic endothelial monolayer integrity. The proliferative effect of LNT-shZO1 correlated with control ECD but not with donor age. Within a low-ECD cohort an ∼30% increase in ECD was observed. LNT-ZONAB achieved a >200-fold overexpression of ZONAB mRNA, which led to an ∼25% increase in ECD.

Conclusions

ZO-1 downregulation or ZONAB upregulation increases corneal ECD via interference with contact inhibition and cell cycle control. With further development, such approaches might provide a means for improving ECD in donor corneas before transplantation.

Sustained and Widespread Gene Delivery to the Corneal Epithelium via In Situ Transduction of Limbal Epithelial Stem Cells, Using Lentiviral and Adeno-Associated Viral Vectors

Corneal epithelial dystrophies are typically characterized by symptoms such as pain, light sensitivity, and corneal opacification leading to impaired vision. The development of gene therapy for such conditions has been hindered by an inability to achieve sustained and extensive gene transfer, as the epithelium is highly replicative and has evolved to exclude foreign material. We undertook a comprehensive study in mice aiming to overcome these impediments. Direct injection of lentiviral vector within the stem cell niche resulted in centripetal streaks of epithelial transgene expression sustained for >1 year, indicating limbal epithelial stem cell transduction in situ. The extent of transgene expression varied markedly but at maximum covered 26% of the corneal surface. After intrastromal injection, adeno-associated viral (AAV) vectors were found to penetrate Bowman's membrane and mediate widespread, but transient (12-16 days), epithelial transgene expression. This was sufficient, when applied within a Cre/lox system, to result in recombined epithelium covering up to approximately 80% of the corneal surface. Lastly, systemic delivery of AAV2/9 in neonatal mice resulted in extensive corneal transduction, despite the relative avascularity of the tissue. These findings provide the foundations of a gene therapy toolkit for the corneal epithelium, which might be applied to correction of inherited epithelial dystrophies.

Marine Sponge-Derived Streptomyces sp. SBT343 Extract Inhibits Staphylococcal Biofilm Formation

Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to absence of cell toxicity, the extract might represent a good starting material to develop a future remedy to block staphylococcal biofilm formation on contact lenses and thereby to prevent intractable contact lens-mediated ocular infections.

Conjunctival lymphangioma in a 4-year-old girl revealed tuberous sclerosis complex

Background: To present a case of conjunctival lymphangioma in a 4-year-old girl with tuberous sclerosis complex. Methods/results: A 4-year-old girl presented with a relapsing cystic lesion of the bulbar conjunctiva in the right eye with string-of-pearl-like dilation of lymphatic vessels and right-sided facial swelling with mild pain. Best-corrected vision was not impaired. Examination of the skin revealed three hypomelanotic macules and a lumbal Shagreen patch. Magnetic resonance imaging (MRI) findings displayed minimal enhancement of buccal fat on the right side. Cranial and orbital MRI showed signal enhancement in the right cortical and subcortical areas. Genetic analysis revealed a heterozygous deletion encompassing exon 1 and 2 of the TSC1 gene (tuberous sclerosis complex 1 gene), confirming the diagnosis of tuberous sclerosis complex. Conclusion: In conjunctival lymphangioma, tuberous sclerosis complex should be considered as the primary disease.

TGF-β2-induced invadosomes in human trabecular meshwork cells

Primary open-angle glaucoma (POAG) is a leading cause of blindness due to chronic degeneration of retinal ganglion cells and their optic nerve axons. It is associated with disturbed regulation of intraocular pressure, elevated intraocular levels of TGF-β2, aberrant extracellular matrix (ECM) deposition and increased outflow resistance in the trabecular meshwork (TM). The mechanisms underlying these changes are not fully understood. Cell-matrix interactions have a decisive role in TM maintenance and it has been suggested that TGF-β-induced inhibition of matrix metalloproteases may drive aberrant ECM deposition in POAG. Invadopodia and podosomes (invadosomes) are distinct sites of cell-matrix interaction and localized matrix-metalloprotease (MMP) activity. Here, we report on the effects of TGF-β2 on invadosomes in human trabecular meshwork cells. Human TM (HTM) cells were derived from donor tissue and pretreated with vehicle or TGF-β2 (2 ng/ml) for 3d. Invadosomes were studied in ECM degradation assays, protein expression and MMP-2 activity were assessed by western blot and zymography and ECM protein transcription was detected by RT-qPCR. HTM cells spontaneously formed podosomes and invadopodia as detected by colocalization of Grb2 or Nck1 to sites of gelatinolysis. Pretreatment with TGF-β2 enhanced invadosomal proteolysis and zymographic MMP-2 activity as well as MMP-2, TIMP-2 and PAI-1 levels in HTM cell culture supernatants. Rho-kinase inhibition by H1152 blocked the effects of TGF-β2. Concomitant transcription of fibronectin and collagens-1, -4 and -6 was increased by TGF-β2 and fibrillar fibronectin deposits were observed in areas of invadosomal ECM remodelling. In contrast to a current hypothesis, our data indicate that TGF-β2 induces an active ECM remodelling process in TM cells, characterized by concurrent increases in localized ECM digestion and ECM expression, rather than a mere buildup of material due to a lack of degradation. Invadosomal cell adhesion and signaling may thus have a role in POAG pathophysiology.

Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery

PURPOSE

Riboflavin/ultraviolet A (UVA) cross-linking (CXL) of corneal collagen is a novel method of stabilizing corneal mechanical properties and preventing progression of keratectasias. This study was conducted to investigate whether CXL influences ablation rate, flap thickness, and refractive results of excimer laser procedures ex vivo.

METHODS

Corneal epithelium was removed from enucleated porcine eyes, and CXL was performed with riboflavin 0.1% and UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. Control eyes received epithelial abrasion only. Diffusion of riboflavin through the cornea was assessed by using infrared-excited, two-photon microscopy of riboflavin autofluorescence, combined with second-harmonic generation of fibrillar collagen. During phototherapeutic keratectomy, corneal thickness was measured by optical coherence pachymetry. During LASIK for myopia, the flap thickness of microkeratome cuts was measured and the induced refractive change assessed by Placido topography. Data were analyzed by Shapiro-Wilk test and Student's t-test.

RESULTS

Multiphoton imaging showed a rapid (30-minute) and even distribution of riboflavin throughout the corneal stroma. No difference in ablation rate was measured in treated and untreated corneas (P = 0.90). Mean flap thickness was increased by 44% in cross-linked corneas (P < 0.01). After LASIK for myopia of 4 to 25 D, the mean corneal refractive change was reduced in CXL-treated eyes by 20.1% (P < 0.05). This effect was less pronounced in thinner flaps.

CONCLUSIONS

CXL reduces the amount of refractive change after LASIK for myopia. Although the laser ablation rate is unaffected, CXL results in an increased flap thickness. This study suggests the need for adjustment of microkeratome and laser parameters for LASIK after CXL and indirectly endorses the theory of a direct stiffening effect of CXL.

Substrate rigidity modulates cell matrix interactions and protein expression in human trabecular meshwork cells

PURPOSE

Extracellular matrix (ECM) composition, tension, and rigidity modulate cell-ECM interactions and have substantial impact on cell functions. The authors studied the effects of ECM rigidity on human trabecular meshwork (HTM) cells to assess ECM rigidity as a possible pathophysiologic factor in glaucoma.

METHODS

Trabecular meshwork cells derived from donor cornea rings and passaged three to seven times were plated on collagen-coated tissue culture plastic or polyacrylamide gels of different rigidity. Cell spreading and focal adhesions were assessed by immunofluorescence microscopy. Expression of focal adhesion kinase (FAK), alpha-smooth muscle actin (alpha-SMA), tubulin, alpha-B-crystallin and GAPDH, as well as phosphorylation of FAK and serum-induced activation of ERK, were studied by Western blot. The subcellular distributions of alpha-SMA and fibronectin were examined by confocal immunofluorescence microscopy.

RESULTS

ECM rigidity modulated cell spreading and focal adhesion size. FAK activation and serum-induced ERK phosphorylation increased with rising substrate rigidity. Expression of alpha-SMA and recruitment of alpha-SMA to stress fibers were enhanced on rigid substrates, whereas myocilin and alpha-B-crystallin expression increased on soft substrates. The structure of fibronectin deposits differed on stiff and soft matrices.

CONCLUSIONS

Extracellular matrix rigidity modulates cytoskeletal structures, protein expression patterns, signal transduction, and fibronectin deposition in HTM cells. ECM changes altering trabecular meshwork resiliency may therefore have significant effects on ocular outflow tract functions with implications in glaucoma.

Yersinia enterocolitica invasin protein triggers differential production of interleukin-1, interleukin-8, monocyte chemoattractant protein 1, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha in epithelial cells: implications for understanding the early cytokine network in Yersinia infections

Yersinia enterocolitica infection of epithelial cells results in interleukin-8 (IL-8) mRNA expression. Herein we demonstrate that besides IL-8, increased mRNA levels of five other cytokines, IL-1alpha, IL-1beta, monocyte chemoattractant protein 1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor alpha (TNF-alpha), can be detected upon infection of HeLa cells with Yersinia. Yersinia-triggered cytokine production was not affected by blocking phosphatidylinositol-3-phosphate kinase with wortmannin, which inhibited bacterial invasion. Comparable cytokine mRNA responses were triggered by Escherichia coli expressing Yersinia inv, while no response was triggered by an inv-deficient Yersinia mutant. Moreover, cytokine responses were independent from metabolic activity of the bacteria, as killed bacterial cells were sufficient for triggering cytokine responses in HeLa cells. Semiquantitative reverse transcription-PCR analysis was used to assess the kinetics of cytokine mRNA expression in infected HeLa cells. IL-8, IL-1alpha, IL-1beta, MCP-1, GM-CSF, and TNF-alpha mRNA expression increased within 1 h postinfection, reached a maximum after 3 to 4 h, and then declined to preinfection levels within 3 h. IL-8, MCP-1, and GM-CSF were secreted by HeLa cells, whereas IL-1alpha and IL-1beta were not secreted and thus were found exclusively intracellularly. TNF-alpha protein could not be detected in cell lysates or supernatants. Stimulation of HeLa cells with IL-1alpha was followed by increased IL-8 mRNA expression, whereas stimulation with IL-8 did not induce cytokine production. Likewise, MCP-1 and GM-CSF did not induce significant cytokine responses in HeLa cells. Our results implicate that the initial host response to Yersinia infection might be sustained by IL-8, MCP-1, and GM-CSF produced by epithelial cells.

Wortmannin blocks Yersinia invasin-triggered internalization, but not interleukin-8 production by epithelial cells

In response to bacterial infection epithelial cells up-regulate expression and secretion of proinflammatory cytokines. Previous work from our laboratory showed that basolateral infection of polarized T84 cells with Yersinia enterocolitica induces interleukin-8 (IL-8) secretion in the absence of significant invasion. Here we studied Y. enterocolitica-induced IL-8 secretion by epithelial HeLa cells as a function of Yersinia invasion or adhesion. For this purpose we tried to separated induction of IL-8 secretion from invasion by treating HeLa cells with signal transduction inhibitors prior to infection. While staurosporin and genistein inhibited both Yersinia invasion and Yersinia-triggered IL-8 secretion, wortmannin, an inhibitor of the phosphatidylinositol-3-phosphate kinase (PI3-K), blocked invasion of Y. enterocolitica into HeLa cells but did not show any effect on IL-8 secretion. These results suggest that Yersinia adhesion might be sufficient to induce IL-8 secretion by epithelial cells. Further analysis demonstrated the requirement of the Yersinia invasion locus inv for adhesion-mediated induction of IL-8 secretion. Thus, HeLa cells infected with an E. coli strain expressing the Y. enterocolitica inv locus induced IL-8 secretion in the presence and absence of wortmannin. Reverse transcription-polymerase chain reaction analysis revealed that adhesion of inv-expressing Y. enterocolitica or E. coli results in the transcriptional activation of the IL-8 gene. These results suggest that Y. enterocolitica adhesion to host cells via Inv activates de novo synthesis and secretion of IL-8.