Evaluation of neopterin levels and kynurenine pathway in patients with acute coronary syndrome.

BACKGROUND: Coronary atherosclerosis is the leading cause of coronary artery disease. Several investigations have indicated that tear-sensitive plaques contain macrophages and T cells. Neopterin is an essential cellular immune response biomarker. The main goal of this study was to see if there were any changes in biomarkers like unconjugated pteridines, neopterin, and biopterin, as well as kynurenine pathway enzymes like indoleamine 2,3-dioxygenase (IDO), which catalyzes the rate-limiting step in tryptophan degradation, in patients with the acute coronary syndrome (ACS) caused by angiographic atherosclerosis. METHODS: High-performance liquid chromatography was used to determine the amounts of neopterin, biopterin, and creatinine in urine samples, as well as tryptophan and kynurenine in serum samples. The enzyme-linked immunosorbent assay was used to assess the amounts of neopterin in serum samples. The measured parameters were evaluated between ACS patients and controls. RESULTS: The measured levels of neopterin, biopterin and the kynurenine to tryptophan ratio reflecting IDO activity, and the specifically known biomarkers such as cardiac troponin, creatine kinase, myoglobin, and natriuretic peptides are statistically higher in ACS patients compared to control subjects. On the other hand, the measured parameters are inadequate to classify the conventional kinds of ACS, ST-elevation- and non-ST-elevation- myocardial infarction. CONCLUSIONS: The study found that determining and using neopterin and IDO parameters as biomarkers in individuals with the ACS can support traditional biomarkers. However, it can be concluded that evaluating pteridine biomarkers solely have no privilege to clinical findings in ACS diagnosis and classification.

Neopterin and biopterin levels and tryptophan degradation in patients with diabetes.

This study aimed to evaluate the possible changes of neopterin, biopterin levels and tryptophan degradation in diabetes and to compare the results within diabetes groups and with healthy subjects. Diabetes mellitus patients and healthy controls were recruited the study. Patients were further subgrouped according to their drug therapy. Serum neopterin concentrations were detected by ELISA. Urinary neopterin, biopterin, serum tryptophan (Trp) and kynurenine (Kyn) levels were detected by HPLC. There was no difference between controls and diabetes patients in serum neopterin, urinary neopterin and biopterin levels (p > 0.05, all). Serum Trp and Kyn levels were significantly different in type 1 diabetes (T1DM) patients compared to controls (p < 0.05, both). Serum neopterin levels were significantly higher in type 2 diabetes patients (T2DM) compared to T1DM (p < 0.05). Urinary biopterin levels of T2DM patients using both metformin and vildagliptin were significantly higher than T1DM patients (p < 0.05). The correlations between serum neopterin and urinary neopterin, Kyn and Kyn/Trp were statistically significant in control and patient groups (p < 0.05, all). The study showed that Kyn/Trp was altered in diabetes patients due to immune modulation. On the other hand, although xenobiotic exposure may change pteridine levels, metformin and/or vildagliptin use in T2DM patients did not have any effect on the measured parameters.

Neopterin Levels and Indoleamine 2,3-Dioxygenase Activity as Biomarkers of Immune System Activation and Childhood Allergic Diseases.

BACKGROUND: Although Th2 immune activation is predominant in allergic diseases, neopterinlevels and indoleamine 2,3-dioxygenase (IDO)-1 activity (kynurenine:tryptophan ratio), which reflect Th1 immune activity, increase with interferon-gamma (IFN-γ) stimulation. We investigated neopterin, tryptophan, and kynurenine levels as biomarkersof the Th1 immune system activation and changes in IDO-1 activityin children with asthma, allergic rhinitis, and atopic dermatitis, as well as the relationship between these biomarkers and the total IgE level, age, and disease severity. METHODS: We divided 205 children (80 girls and 125 boys, four months to 17 years old) into four groups: controls, patients with asthma, patients with allergic rhinitis, and patients with atopic dermatitis. Peripheral venous blood samples were collected. Neopterin levels were determined by an enzyme immunoassay. Tryptophan and kynurenine levels were analyzed using HPLC. IDO-1 enzyme activity was calculated using tryptophan and kynurenine levels. IgE levels were measured. The Mann-Whitney U test, Kruskal-Wallis test, and Conover post-hoc method were used for statistical analysis. RESULTS: Neopterin, tryptophan, and kynurenine levels were higher and IgE levels and IDO-1 enzyme activity were lower in patients with asthma and allergic rhinitis than in controls (P<0.05). Patients with atopic dermatitis showed higher neopterin, tryptophan, and kynurenine levels, higher IDO-1 activity, and lower IgE levels thancontrols (P<0.05). CONCLUSIONS: The Th1/Th2 balance is disrupted in children with allergic diseases, concomitant with increased Th1-mediated immune response activation and reduced IgEproduction, which is promoted by Th2-type cytokines.

Tryptophan Degradation and Antioxidant Status in Patients With Thyroid Disorders.

BACKGROUND: The aim of this study was to evaluate the degradation of tryptophan (Trp), neopterin production and antioxidant capacity in patients with benign and malignant thyroid disease. METHODS: For this reason, the levels of tryptophan, kynurenine (Kyn) and neopterin, and superoxide dismutase (SOD) and catalase (CAT) enzyme activities in 67 thyroid patients were evaluated in our study and the results were compared with 30 healthy controls. RESULTS: Tryptophan and kynurenine levels in thyroid patients decreased compared to the control group. Patients with thyroid disease had lower CAT activity than the control group. The neopterin and tryptophan levels in malignant and benign patients were also significantly different. CONCLUSION: The results of the present study suggest that thyroid disorders may lead to changes in tryptophan degradation, neopterin production and CAT enzyme activities.