Anna Matysik-Woźniak1, Roman Paduch2, Waldemar A Turski3, Ryszard Maciejewski4, Anselm G Jünemann5, Robert Rejdak6. 1. Department of General Ophthalmology, Medical University of Lublin, Lublin, Poland. Electronic address: anna.matysik@umlub.pl. 2. Department of General Ophthalmology, Medical University of Lublin, Lublin, Poland; Department of Virology and Immunology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland. Electronic address: rpaduch@poczta.umcs.lublin.pl. 3. Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Lublin, Poland. Electronic address: waldemar.turski@umlub.pl. 4. Department of Human Anatomy, Medical University of Lublin, Lublin, Poland. Electronic address: ryszard.maciejewski@umlub.pl. 5. University Eye Hospital, Rostock, Germany. Electronic address: anselm.juenemann@med.uni-rostock.de. 6. Department of General Ophthalmology, Medical University of Lublin, Lublin, Poland; Medical Research Centre, Polish Academy of Science, Warszawa, Poland. Electronic address: robertrejdak@yahoo.com.
Abstract
BACKGROUND: Tryptophan metabolites formed along kynurenine pathway may affect cell proliferation and tissue function. This pathway presents potential sites for drug discovery. Tryptophan and its metabolites kynurenine and kynurenic acid may be involved in the physiology and pathology of the ocular surface. The purpose of this work is to investigate the effect exerted by tryptophan, kynurenine and kynurenic acid upon corneal epithelium. METHODS: A SkinEthic™ HCE human reconstructed corneal epithelium model was used. WST-1 test was used to examine cell proliferation and viability, and the Griess reaction for nitric oxide determination. The levels of IL-6 and IL-10 were measured by means of ELISA assay. All analyses were carried out after the cells were exposed to tryptophan, kynurenine and kynurenic acid at concentrations of 5, 50 or 100μM for 0-24h and 24-48h. RESULTS: Tryptophan (100μM), kynurenine (100μM) and kynurenic acid (5-100μM) slightly increased the viability and proliferation of corneal epithelium. All of the tested compounds decreased cellular NO release. Kynurenine (50-100μM) and tryptophan (50-100μM) decreased while tryptophan (5μM) and kynurenic acid (100μM) increased the release of IL-6. All of the tested substances increased the level of IL-10 and decreased the IL-6 to IL-10 ratio. CONCLUSIONS: Tryptophan, kynurenine and kynurenic acid affect physiological processes in corneal epithelium and therefore may play a significant role in the physiology and pathology of the ocular surface. Our results indicate that the use of these compounds may be considered in the treatment of ocular surface diseases.
BACKGROUND:Tryptophan metabolites formed along kynurenine pathway may affect cell proliferation and tissue function. This pathway presents potential sites for drug discovery. Tryptophan and its metabolites kynurenine and kynurenic acid may be involved in the physiology and pathology of the ocular surface. The purpose of this work is to investigate the effect exerted by tryptophan, kynurenine and kynurenic acid upon corneal epithelium. METHODS: A SkinEthic™ HCEhuman reconstructed corneal epithelium model was used. WST-1 test was used to examine cell proliferation and viability, and the Griess reaction for nitric oxide determination. The levels of IL-6 and IL-10 were measured by means of ELISA assay. All analyses were carried out after the cells were exposed to tryptophan, kynurenine and kynurenic acid at concentrations of 5, 50 or 100μM for 0-24h and 24-48h. RESULTS:Tryptophan (100μM), kynurenine (100μM) and kynurenic acid (5-100μM) slightly increased the viability and proliferation of corneal epithelium. All of the tested compounds decreased cellular NO release. Kynurenine (50-100μM) and tryptophan (50-100μM) decreased while tryptophan (5μM) and kynurenic acid (100μM) increased the release of IL-6. All of the tested substances increased the level of IL-10 and decreased the IL-6 to IL-10 ratio. CONCLUSIONS:Tryptophan, kynurenine and kynurenic acid affect physiological processes in corneal epithelium and therefore may play a significant role in the physiology and pathology of the ocular surface. Our results indicate that the use of these compounds may be considered in the treatment of ocular surface diseases.