Biomarkers and specific optical devices for express in vivo diagnosis of corneal infections – FluoCor

Corneal infections, namely infectious keratitis (IK) are frequent worldwide and the first cause of unilateral blindness. They involve bacteria, viruses, fungi and parasites. Although their epidemiology vary with sanitary conditions, Gram + bacteria and herpetic viruses (HSV1-2) represent most of the cases. Fungi and amoebas come in second position but are always severe. IK sequelae are variable but may potentially result in loss of the eyeball. The prognosis is worsened by a delayed diagnosis.
Up to know, their diagnosis rely on the clinical examination using a slit lamp and on the microbiological tests. With some exceptions, clinical signs are globally little specific and do not allow determining the infectious agent involved with certainty. Positive and negative predictive values of direct examination ad cultures are low and the answered is delayed. Sophisticated tests like the in vivo confocal microscopy (IVCM) and biomolecular technologies are not routine everywhere. IVCM remains dependant on the observers’ skill.
Our FLUOCOR project, with the certification of LYONBIOPOLE, aims at proposing an immediate and specific diagnosis of the most frequent and/or the most severe IK, thanks to fluorescent biomarkers (fBM) of infectious agents. For the first time, they will allow an in vivo etiologic diagnosis. After instillation, incubation, and rinsing, the patients’ corneal staining will be observed through a specific fluorescent imaging device. Our triple innovation relies on: 1/ the use of biomolecules specific for infectious agents (Vancomycine for Gram + bacteria, anti-HSV antibodies, and anti-amoebas) bioconjugated with BODIPY fluorophores that are excited with far red (FR) and near infrared (NIR) lights; 2/ The use of a fluorescent IVCM (fIVCM); 3/the experimentation on human corneas stored in an innovative bioreactor. The FR-NIR-window is the best diagnosis window for the in vivo diagnosis (lowest autofluorescence and deep tissue penetration). It is particularly adapted for the photophobic eye since FR is not dazzling and NIR invisible, contrary to the bright blue (dazzling and potentially phototoxic for the macula), necessary to excite fluorophores belonging to the family of fluoresceine. We obtained the POC of the identification of S. Aureus and HSV thanks to fBm revealed by fIVCM, on human corneas stored and infected in the Bioreactor (best oral translational research paper of the European congress EVER2013). The fIVCM is also an innovation of our laboratory (adaptation for Ophthalmology of a Dermatology device) but WILL NOT BE WIDESPREAD TO THE OPHTHALMOLOGY COMMUNITY. On the contrary, the optical device that we will develop, will be simpler and less expensive than fIVCM and will be distributed thanks to the worldwide network of Thea.
FLUOCOR is a 2-year industrial research project, with a public-private partnership. It associates our universitary laboratory of Ophthalmology, EA2521 titled ‘Biology, imaging and engineering of Corneal Graft’ that will have to assess the efficacy of labelling on two models (human corneas stored in our bioreactor that recreate the physiological environment, and animal experiment), the laboratory Chimie Organique et de Spectroscopie Avancée UMR/CNRS of Strasbourg, the undisputed international leader in BODIPY fluorophores, that will be responsible of the synthesis and purification of the fBm, the laboratory Hubert Curien, specialized in optical instruments, and the pharmaceutical company THEA (C-Ferrand), french Ophthalmology specialist, powerful engine for innovation in corneal diseases, that will be responsible for pharmaceutical formulation, industrialisation and selling of the fBMs and of the optical device thanks to its worldwide network of subsidiary and distributors.