Recent studies have shown that derangements in kynurenine pathway metabolite levels are associated with various pathologies such as neurodegenerative diseases, schizophrenia, depression, bipolar disorder, rheumatoid arthritis, and cancer. Therefore, reliable, accurate, fast, and multiplex measurement methods for kynurenines have become increasingly important. This study aimed to validate a new mass spectrometric method for analyzing tryptophan metabolites. A tandem mass spectrometric method, including protein precipitation and evaporation steps, was developed to measure serum levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid. Samples were separated using a Phenomenex Luna C18 reversed-phase column. The kynurenine pathway metabolites were detected by tandem mass spectrometry. The developed method was validated according to Clinical & Laboratory Standards Institute (CLSI) guidelines and applied to hemodialysis samples. The developed method was linear at the concentrations of 48.8 – 25,000, 0.98 – 500, 1.2–5000, 1.2–5000, and 0.98–250 ng/mL for tryptophan, kynurenic acid, kynurenine, 3-hydroxyanthranilic acid, and 3-hydroxykynurenine, respectively. The imprecisions were less than 12 %. The median serum concentrations of tryptophan, kynurenine, kynurenic acid, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid were 10530, 1100, 218, 17.6, and 25.4 ng/mL in pre-dialysis blood samples, respectively. They were 4560, 664, 135, 7.4, and 12.8 ng/mL in post-dialysis blood samples, respectively. A fast, simple, cost-effective, accurate, robust, and validated tandem mass spectrometric method was developed, and the method was successfully used for the quantitation of kynurenine pathway metabolite concentrations in hemodialysis patients.

Objective: In this study, we aimed to evaluate subclinical atherosclerosis in patients with obesity who had cardiovascular disease risk indicators such as arterial stiffness, which is evaluated using pulse wave velocity (PWV), carotid intima-media thickness (CIMT), and biomarkers of endothelial dysfunction such as endocan, ADAMTS97, and ADAMTS9. Subjects and methods: Sixty obese subjects, including 23 subjects with body mass index (BMI) ≥ 40, 37 subjects with BMI ≥ 30 but < 40, and 60 age-and sex-matched control subjects, were

Background/aim: Data on the presence and extent of cardiovascular disease (CVD) risk in primary hyperparathyroidism (PHPT) are conflicting. In our study, we aimed to investigate the increased CVD risk in patients with PHPT by carotid intima-media thickness (CIMT), epicardial adipose tissue (EAT) thickness, and serum levels of endocan and nesfatin-1. Materials and methods: Patients with PHPT (n = 44) and age- and sex-matched healthy control subjects (n = 40) were enrolled in this study. Demographic data of the participants were questioned. Serum endocan and nesfatin-1 concentrations were assessed using commercially available ELISA kits. Noninvasive measurements of CIMT and EAT thickness were made with high-resolution ultrasonography and B-mode echocardiography. Results: There was no statistically significant difference in serum endocan and nesfatin-1 levels and EAT thickness in the PHPT group compared to controls. CIMT was statistically significantly higher in the PHPT group compared to controls (p = 0.001). A negative correlation was found between PTH and low-density lipoprotein cholesterol level (p = 0.001) but no significant relationship was found between other parameters. Conclusion: We found that CIMT is increased in patients with PHPT and consequently, CVD risk is high in these patients. More comprehensive studies are needed to identify other markers that predict increased CVD risk in patients with PHPT.