Cyclosporine A (CsA) concentrations in aqueous and vitreous humour samples and clinical and ophthalmological findings in 16 equine eyes after implantation of a sustained-release CsA delivery device

Wollanke, Bettina und Gerhards, Hartmut (2021): Cyclosporine A (CsA) concentrations in aqueous and vitreous humour samples and clinical and ophthalmological findings in 16 equine eyes after implantation of a sustained-release CsA delivery device. In: Pferdeheilkunde, Bd. 37, Nr. 3: S. 234-240

Abstract

Suprachoroidal and subconjunctival implantation of devices which provide a sustained release of cyclosporine A (CsA) have been repeatedly described to have a beneficial effect on eyes suffering from ERU or immune-mediated keratitis. These implants are thought to deliver CsA into the eye and eye-tissues for a period of about three years. However, some horses which have been treated with a CsA implant show an ongoing inflammation and a deterioration of the ocular findings within months after having received the device. Several horses which have been treated previously with implantation of a CsA pellet have been submitted to the Equine Clinic of the Ludwig-Maximilians-University of Munich. Only one eye in each horse had been subjected to CsA pellet implantation. One horse had received three implants in one instance, another horse had received two implants within 4 months. Two implants were located suprachoroidally and 14 implants were located subconjunctivally or episclerally. Intraocular samples could be taken from 16 of those horses. Ten of these horses suffered from recurrent uveitis and underwent vitrectomy, which provided undiluted vitreous humour that could be taken at the beginning of surgery. One of these horses had been rubbing the eye since the implantation of the device. Three horses had a chronic keratitis and two horses had a chronic iritis. Aqueous chamber fluid was taken from these five horses for laboratory tests regarding an intraocular leptospiral infection and all were tested negative. The last eye had suffered from a chronic kerato-uveitis of unknown cause for a long time, and had developed a severe atrophy requiring enucleation. After removal, a vitreous humour sample could be taken. The sampling of intraocular fluids was performed 3 months up to 3 years after the implantation of the CsA devices. All intraocular fluid samples were tested for cyclosporine concentrations. The lowest detection limit was 10 mu g/l. No CsA could not be detected at all (CsA < 10 mu g/l) in all but one of the intraocular samples. The only sample in which CsA was detected (38.5 mu g/l), had received three CsA implants 4 months previously. The CsA implants were removed in 8/10 horses in which a vitrectomy was performed because they provided no benefit and lay in positions disturbing the laser-sclerotomy required for vitreous surgery. All but one implant were located episclerally. No further bouts of uveitis occurred after vitrectomy. The CsA implants had to be removed in the horses suffering from keratitis to allow corneal healing by vascularisation. One of these implants was located suprachoroidally. It can be concluded that CsA cannot be detected in intraocular fluid samples when just one CsA device is used, not even during the first six months after implantation, independent of its location. However, a very low and indetectable concentration of CsA may be present which reduces uveitis activity. A low concentration of CsA could be detected (38.5 mu g/l) in the horse with three CsA devices which had been placed episclerally. In the case of eyes suffering from chronic keratitis, vascularisation of the cornea may have more benefit than immunosuppressive medications including CsA devices.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Tiermedizin > Zentrum für Klinische Tiermedizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0177-7726
• Sprache: Englisch