La kératite à Acanthamoeba (KA) est une kératite infectieuse rare et grave,potentiellement cécitante. L'infection est causée par Acanthamoeba spp., unprotozoaire ubiquitaire présent dans le sol, l'air et l'eau. Jusqu'à 85% des cas de KAsont associés au port de lentilles cornéennes, et plus rarement suite à untraumatisme.Actuellement, aucune molécule n’a d’autorisation de mise sur le marché danscette indication dans l'Union européenne et aux États-Unis. Ces dernières années,des combinaisons d'agents anti-amibiens tels que les biguanides et les diamidinesont été utilisées comme traitement de référence. Cependant, les schémasthérapeutiques et les concentrations d'agents actifs reposent sur des donnéesempiriques. Récemment, le voriconazole, antifongique triazolé, a été utilisé avecsuccès pour traiter des KA humaines. Malgré cela, la communauté ophtalmologiquese heurte le plus souvent dans les formes sévères à de grandes difficultés de prise encharge et se retrouve parfois en situation d’impasse thérapeutique. La pertefonctionnelle et anatomique de l’oeil est encore possible.A partir d’un modèle de KA chez le rat, plusieurs molécules et voiesd’administration ont été testées. Dans une première partie, en lien avec projeteuropéen ODAK (Orphan drug for Acanthamoeba Keratitis), nos travaux ont suggéréqu’une concentration de collyre PHMB supérieure ou égale à 0,04% devait êtrepréférée. Dans une deuxième partie, nous avons pu montrer la supériorité duvoriconazole en collyre par rapport à la voie orale. Enfin, l’étude de lapharmacocinétique du voriconazole et du posaconazole après injections directesintracornéennes, démontre leur faible utilité en clinique humaine du fait de lafréquence nécessaire de réinjection, bien que des analyses complémentairesconcernant le posaconazole en collyre pour confirmer son intérêt soient nécessaires.L'ensemble de ces travaux pourrait permettre d’adapter les protocolesthérapeutiques de la KA. / Acanthamoeba keratitis (AK) is a rare and severe form of infectious keratitis,which is potentially sight-threatening. The infection is caused by Acanthamoeba spp.a common protozoan present in soil, air and water. Up to 85% of AK cases areassociated with contact lens wearing, more rarely after corneal injury.Currently, there are no agents approved for the treatment of AK in theEuropean Union or in the United States of America. In recent years, combinations ofunlicensed anti-amoebic agents such as biguanides and diamidines have been usedas the reference treatment. Treatment regimens and concentrations of active agentsare based on empirical data. Recently, voriconazole, a mono-triazole, wassuccessfully used to treat cases of human AK. Despite this, the ophthalmologicalcommunity is most often faced with severe forms of the disease with severemanagement difficulties and sometimes with a situation of therapeutic impasse. Thefunctional and anatomical loss of an eye can occur.Several agents and routes of administration have been tested in a rat model ofAK. First, as part of the European ODAK project (Orphan drug for AcanthamoebaKeratitis), our work suggested that a concentration of PHMB eye drops greater thanor equal to 0.04% should be preferred. Second, we were able to show the superiorityof voriconazole in eye drops compared to the oral route. Finally, our study on thepharmacokinetics of voriconazole and posaconazole after intrastromal injections,demonstrates their low utility in human because of the need for frequent reinjection.Nevertheless, additional analyses are necessary to confirm the interest ofposaconazole eye drops. All of this work could make it possible to adapt thetherapeutic protocols of AK.

Background: A mouse model of combined UVA/riboflavin irradiation to eliminate stromal cells and other antigen-presenting cells in the cornea provides the basis for a probably low risk of corneal transplantation. Methods: After abrasion of the epithelium, the central corneas of mouse eyes were treated with UVA/riboflavin in vitro. Histological studies of hematoxylin-eosin and immunohistochemical staining with caspase 3 were performed. Dissected mouse corneas were analyzed by Western blot. Results: Apoptotic cells were shown on the central corneal stroma; a cell-free zone was displayed in the cornea. Numbers of dead cells increased according to cultivation time. However, the endothelium survived due to the adjustment of the irradiation dose. Conclusions: A cell-free zone in the stroma of the mouse cornea was produced by UVA/riboflavin irradiation in vitro. The technique makes possible to prevent or reduce immunological reactions and the risk of graft rejection by pretreatment of the donor cornea, ultimately prolonging graft survival. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Experimental models of a transfer of stem cells for therapeutic purposes Abstract Stem cell therapy currently represents a standard procedure of treating a wide variety of hereditary diseases and serious injuries. Development of the most suitable way of transfer of stem cells into the patient body remains very important question concerning this type of therapy. In our experiments we used nanofiber scaffolds for stem cell cultivation and their subsequent transfer. These nanofibers were prepared by the original needleless electrospun NanospiderTM technology. Allogeneic cornea or skin graft were transplanted from B6 mice to BALB/c mice. The grafts were covered by a nanofibrous scaffold with cultivated stem cells. Stem cells were stained by an imunofluorescent dye to enable us to monitore their migration from nanofibers into tissues and consequent distribution in the body and characterize changes of this distribution in the time. The methods of ELISA and PCR were used to confirm that mesenchymal stem cells support the production of antiinflammatory cytokines IL-4 and IL-10 and contribute to inhibition of production of proinflammatory cytokines IL-1, IFNγ and inducible nitric oxide synthase. We confirmed an important beneficial role of nanofiber scaffolds in transplantation of mesenchymal stem cells. Nanofiber...

L'orientation des lentilles sclérales devient extrêmement importante pour maximiser la stabilité et la vision chez des patients qui portent des lentilles ayant une face antérieure torique. Les techniques cliniques actuelles pour déterminer la rotation d'une lentille sclérale impliquent l'utilisation de lentilles diagnostiques; cependant, ces méthodes nécessitent beaucoup de temps de chaise pour obtenir un ajustement optimal. Des appareils novateurs existent maintenant pour évaluer la forme de la surface oculaire et peuvent s’avérer utiles pour prédire la rotation des lentilles sclérales et augmenter l'efficacité globale des ajustements. Le but de cette étude comparative et randomisée était d'évaluer la rotation des lentilles sclérales en se basant sur des valeurs fournies par deux topographes. Quinze participants ont été recrutés et leurs deux yeux ont été imagés à l'aide de deux topographes: le Eye Surface Profiler (ESP) et le Cornea Sclera Profile (CSP). Les participants ont ensuite été ajustés avec la lentille OneFit MED dans un oeil et la Zenlens dans l'autre. La rotation de chaque lentille a été évaluée à l’aide de la lampe à fente et comparée à l’axe le plus cambré de l’astigmatisme conjonctival identifié par chaque topographe. Bien que les rotations des deux instruments ne soient pas comparables, l'ESP a prédit une rotation à moins de 15° de l'observation à la lampe à fente, ce qui la rend cliniquement acceptable pour les lentilles avec de faibles valeurs de puissance cylindrique. L'acuité visuelle des patients portant des lentilles avec des quantités élevées de toricité pouvant être plus affectée par la quantité de rotation, les ajustements empiriques semblent, à ce stade, être déconseillés pour ces cas. / Scleral lens orientation becomes extremely important to maximize vision and lens stability in patients who are fitted in front-toric lenses. Current clinical techniques to determine the rotation of a scleral lens involve the use of diagnostic lenses; however, these methods require a substantial amount of chair time to achieve an optimal fit. Contemporary equipment exists to evaluate ocular surface shape, which could be useful in predicting scleral lens rotation and increasing the overall efficiency of scleral lens adjustments. The goal of this comparative and randomized study was to evaluate scleral lens rotation based on the values provided by two scleral topographers. Fifteen participants were recruited and both eyes were imaged using two scleral topographers: the Eye Surface Profiler (ESP) and the Cornea Sclera Profile (CSP). Participants were fitted with the OneFit MED on one eye and the Zenlens on the other. Each lens’s rotation was evaluated at the slit lamp and compared to the steep axis of conjunctival astigmatism identified by each topographer. While the rotations from both instruments are not comparable, the ESP predicted rotation within 15˚ from slit lamp observation, which makes it clinically acceptable for lenses with low values of cylindrical power. The visual acuity of patients wearing lenses with a high amount of toricity may be affected by the amount of rotation and are not suitable for empirical fittings at this point in time.

P.Trošan Ph.D. Thesis Abstract Limbal stem cell deficiency (LSCD) is a disease characterized by the deficiency of stem cells in the limbus, which are responsible for the homeostasis and renewal of the corneal epithelium. This disorder results in corneal neovascularization, chronical inflammation and opacification, which may lead to loss of vision. The most successful treatment is the transplantation of limbal tissue or cultured limbal epithelial cells (LECs) onto the damaged ocular surface. The human amniotic membrane (HAM) is used as the feeder of the LECs culture, as well as for the LSCD treatment. HAM is also widely used in clinical practice, particularly for the treatment of chronic wounds. This dissertation is particularly concerned on cell therapy for LSCD, on preparation of cells suitable for grafting onto the ocular surface, on the improvement of the LECs culture conditions, and on the preparation of appropriate carrier for the transfer of cells onto the damaged cornea. During my work I have used a wide spectrum of methods, e.g. cell cultures (LECs, mesenchymal stem, amniotic epithelial, conjunctival epithelial, goblet and 3T3 cells), immunohisto- and immunocytochemistry, microscopy, proliferation and colony forming assays, reverse transcription and quantitative real-time PCRs and statistical...

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Notre projet vise à élucider la relation complexe entre la morphologie des nerfs cornéens et la sensibilité cornéenne, afin d'améliorer la compréhension et le diagnostic des pathologies oculaires. En utilisant deux types d'esthésiomètres : l'esthésiomètre sans contact (NCCA) et le Cochet-Bonnet (CBA) pour mesurer la sensibilité, et en analysant les images de microscopie confocale (IVCM) via le logiciel CCMetrics, nous avons étudié 23 individus, y compris ceux souffrant de diabète et de kératite neurotrophique. Des corrélations négatives significatives entre certains attributs neuronaux et la sensibilité cornéenne ont été identifiées. L'utilisation d'algorithmes d'apprentissage automatique, tels que K-Plus Proches Voisins (KNN), les Réseaux de Neurones (MLP), la Régression à Vecteurs de Support (SVR) et les arbres de décision, a révélé des relations non linéaires complexes. Notre étude encourage l'utilisation de l’apprentissage automatique pour détecter ces relations complexes dans le domaine médical en général et en ophtalmologie en particulier. / Our project aims to clarify the complex relationship between the morphology of corneal nerves and corneal sensitivity, to improve understanding and diagnosis of eye pathologies. We used two types of esthesiometers: a non-contact esthesiometer (NCCA) and Cochet-Bonnet (CBA) for sensitivity measurement and analyzed confocal microscopy (IVCM) images using the software CCMetrics. We studied 23 individuals, including those with diabetes and neurotrophic keratitis. Significant negative correlations between certain neuronal attributes and corneal sensitivity were identified. The use of machine learning algorithms, such as K-Nearest Neighbors (KNN), Neural Networks (MLP), Support Vector Regression (SVR), and decision trees, revealed complex non-linear relationships. Our study advocates using machine learning to detect these complex relationships in the medical field, especially in ophthalmology.

No / To determine whether Hartmann-Shack wavefront sensing detects differences in optical performance in vivo between poly(methyl methacrylate) (PMMA) and foldable acrylic intraocular lenses (IOLs) and between clear corneal and scleral tunnel incisions and whether optical differences are manifested as differences in visual performance. SETTING: Department of Optometry, University of Bradford, West Yorkshire, United Kingdom. METHODS: This study comprised 74 subjects; 17 were phakic with no ocular pathology, 20 had implantation of a Pharmacia 722C PMMA IOL through a scleral tunnel, 21 had implantation of an Alcon AcrySof IOL through a scleral tunnel, and 16 had implantation of an AcrySof IOL through a corneal incision. Visual acuity and contrast sensitivity testing, ocular optical quality measurement using Hartmann-Shack wavefront sensing, and corneal surface measurement with a videokeratoscope were performed in all cases. RESULTS: There were significant differences between groups in the total root-mean-square (RMS) wavefront aberration over a 6.0 mm pupil (F=3.91; degrees of freedom=3,70; P<.05) mediated at the 4th-order RMS, specifically spherical and tetrafoil aberrations. The PMMA-scleral group had the least aberrations and the AcrySof-corneal group the most. For a 3.5 mm diameter pupil, the total higher-order RMS wavefront aberration was not significantly different between the groups (P>.05). There were no differences between groups in corneal shape, visual acuity, or contrast sensitivity. CONCLUSIONS: Implantation of the spherical PMMA IOL led to a slight reduction in total wavefront aberration compared to phakic eyes. AcrySof IOLs induced more aberrations, especially spherical aberration. Corneal-based incisions for IOL implantation compounded this increase. Studies of the optical performance of IOLs in vivo should use wavefront sensing as the main outcome measure rather than visual measures, which are readily confounded by multiple factors.