Pterjiumda Neopterin Düzeylerinin ve Kinürenin Yolağının Değerlendirilmesi

Abstract

Kilicarslan B., Evaluation of Neopterin Levels and Kynurenine Pathway in Pterygium, Hacettepe University Institute of Health Sciences Ph.D. Thesis in Pharmaceutical Toxicology, Ankara, 2018. Pterjium is an inflammatory and degenerative eye disease in which conjunctival tissue grows onto cornea. Despite the fact that factors such as ultraviolet radiation, p53 tumor suppressor gene, immunologic and inflammatory mechanisms play a role in the pathogenesis, its etiology remains unclear. High recurrence rates of pterygium reveals the need for innovative biomarkers such as neopterin in clinical practice. Neopterin is an unconjugated pteridine which expresses cellular immunity and is considered to be an important biomarker in the early diagnosis and prognosis of many pathologies. Another indicator that reflects cellular immunity is the enzyme indoleamine 2,3-dioxygenase (IDO), which plays a role in the formation of kynurenine by consuming tryptophan in the tissues. In this study, immunological activation status was evaluated in pterygium by determination of neopterin concentrations and the ratio of kynurenine/tryptophan, which reflects IDO activity. For this purpose, neopterin, tryptophan and kynurenine levels were measured in pterygium patients (n=31) and healthy control group (n=32). Serum samples were used for systemic evaluation of immune activation and tear samples were used for local evaluation. Compared to control group, serum neopterin concentrations and kynurenine/tryptophan ratio were increased and found to be related to each other in pterygium patients (p<0.05). This demonstrates that IDO activity, an indicator of immunostimulation, is induced in pterygium and immunologic pathways, particularly T-cell mediated immunity, contribute to the pathogenesis of the disease. Our results have been pointed out that neopterin is an important biomarker for diagnosis and monitoring pterygium.

Keywords: pterygium, neopterin, kynurenine, tryptophan, biomarker This thesis was supported by Hacettepe University Scientific Research Projects Coordination Unit with the project numbered THD-2017-16538.