Tryptophan metabolism, inflammation and oxidative stress in osteoarthritis patients

Osteoarthritis (OA) is more complex than a wear-related disease, it is a joint disease in which metabolic and biochemical mechanisms play a role. Aging, obesity, and joint injury are the main risk factors for OA in the development of the disease. Despite the high prevalence, there is currently no drug available to completely eliminate or repair the disease. Identification of OA-related biomarkers may enable us to better understand the etiology and pathogenesis underlying this debilitating disease. The aim of our study is to observe whether the tryptophan-kynurenine pathway is associated with inflammation and oxidative stress in patients with OA. A total of 78 participants, 52 patients and 26 controls, were included in the study. Tryptophan, Kinurenin, TNF-α, IL-36α, Neopterin, oxidative stress marker malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) levels were measured in the patient and control groups. The measured values were compared between the patient and control groups. The values of the patient group and the control group were SOD (10.79±3.6 U/L and 10.39±3.56 U/L), CAT (0,0182±0,0156 U/L and 0,0115±0,0162 U/L), MDA (5.89±0.83 mmol/L and 5.27±0.99 mmol/L), Kynurenine (86555.15±68721.75 ng/L and 107489.51±7729.,98 ng/L), Neopterin (43.57±57.85 ng/L and 37.84±44.65 ng/L), IL36α (0.2±0.22 ng/L and 0.15±0.03 ng/L), Tryptophan (20.21±14.64 ng/L and 22.61±10.4 ng/L), TNF α (43.77±184.13 ng/L and 95.21±440.82 ng/L), respectively. From these measured values, it is seen that IL-36α and Tryptophan values differ statistically, similar to the MDA values, between the patient and control groups (p<0.05). According to the findings of the thesis study, it was concluded that the determination of IL-36α, Tryptophan parameters and their use as a biomarker in osteoarthritis patients may be meaningful and valuable. However, larger patient-based research studies are needed to support the results obtained.