Abstract
Asymptomatic carotid artery stenosis is usually detected by physicians in patients, coincidentally, during an ultrasound examination of the neck. Therefore, measurable biomarkers in blood are needed to define the presence and severity of atherosclerotic plaque in patients to identify and manage it. We hypothesized that biomarkers that indicate pathways related to the pathogenesis of atherosclerosis could be used to identify the presence and severity of plaque in patients. For this purpose, we determined the levels of participants' inflammatory and oxidative stress biomarkers. On the other hand, kynurenine/tryptophan and neopterin levels were measured as relatively new biomarkers of inflammation in this study. Our study included 57 patients diagnosed with asymptomatic carotid artery stenosis and 28 healthy volunteers. Blood kynurenine and tryptophan levels were measured with LCMS/MS. The ELISA assay was used to measure blood catalase, total superoxide dismutase, glutathione peroxidase, malondialdehyde, and neopterin levels. According to our results, while the kynurenine and neopterin levels were higher, the tryptophan levels were lower in patients. Furthermore, the kynurenine to tryptophan ratio, which reflects IDO-1 activity, was higher in patients. On the other hand, catalase, total superoxide dismutase, and malondialdehyde levels were higher, while the glutathione peroxidase activity was lower in patients. Increasing the kynurenine/tryptophan ratio and neopterin level in patients with asymptomatic carotid artery stenosis have been associated with an inflammatory state. The oxidative stress and inflammatory response biomarkers may be an effective diagnostic and prognostic tool for asymptomatic carotid artery stenosis.