ESPE Abstracts

Introduct&idot;on: Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by damage to β cells in the pancreas. Neopterins and indolamine 2,3-dioxygenase (IDO) activity, which is shown by the ratio of kynurenine to tryptophan, can be used as an indicator in the regulation of cellular immunity. Oxidative stress produced by xanthine oxidoreductase has been shown to be associated with vascular endothelial dysfunction. It uses the conversion of pterin to isoxanthopterin to measure xanthine oxidase activity. In our study, we aimed to analyze pteridine derivatives in serum and urine, and tryptophan and kynurenine in serum in children with T1D and compare them with healthy subjects.

Methods: Within the scope of the study, the levels of 6-biopterin, neopterin, monapterin, pterin, isoxanthopterin and pterin-6-carboxylic acid in serum and urine, and tryptophan and kynurenine levels in serum were compared with healthy controls. High performance liquid chromatography methods were used for the analysis of pteridine and tryptophan derivatives.

Results: A median age of 14.0 (12.7-17) years, 93 (43 girls, 77 pubertal) with T1D, and a median age of 14.0 (10-15) years and 71 (38 girls, 51 pubertal)) healthy children were included in the study. There was no difference between the groups in terms of age, gender and puberty. The median age at diagnosis was 9.0 (6.2-12.2) years, and the median follow-up period was 4.0 (1-7.15) years. Serum neopterin, monapterin, 6-biopterin and pterin levels and urinary neopterin, monapterin, isoxantopterin, pterin-6-carboxylic acid, 6-biopterin and pterin levels were found to be higher in children with T1D compared to the control group, but the statistical difference was not significant. High isoxantopterin (P=0.01) and pterin-6-carboxylic acid low (P< 0.001) were statistically significant in children with type 1 diabetes.. While serum tryptophan levels were statistically significantly higher in children with type 1 diabetes compared to the control group (P=0.021), the elevation in elevated serum kynurenine levels was not significant. There was a correlation between serum neoptrein level and duration of diabetes (P=0.045, r= 0.209). There was a correlation between the neoptrein/creatinine and isoxanthopteridine/creatinine levels in the urine and the HbA1c level (P=0.005, r= 0.305; P=0.021, r= 0.249, respectively).

Conclusion: Type 1 diabetes may cause changes in the pteridine and kynurenine pathways. Because it is an indicator of vascular endothelial dysfunction, isoxantopterin can be used as biomarkers to predict complications of T1D.