Metabolic factors and oxidative stress in osteoarthritis: a case-control study

Previous studies suggest that metabolic disturbances might be involved in the development of osteoarthritis (OA). Associations have been found between the individual components of metabolic syndrome (MetS) and OA. MetS has been associated with increased oxidative stress (OxS). The study aimed to clarify the role of MetS components in OA and to evaluate the levels of OxS in OA patients and in age-matched controls. Fifty-five patients with end-stage OA (age 63 ± 7 years) prior to hip or knee joint replacement surgery and 55 age-, gender- and body mass index matched controls (61 ± 8 years) were enrolled in the study. Serum levels of glucose, insulin, c-peptide, cholesterols and OxS markers were recorded. Homeostasis model assessment for insulin resistance was used as the proxy measure of insulin resistance. Radiographic severity was assessed using the Kellgren-Lawrence score. The OA patients had higher total peroxide concentration and oxidative stress index [488 (250-612) μmol/L vs. 326 (168-442) μmol/L, p = .011 and 34 (17-51) vs. 20 (11-28), p = .002, respectively] and decreased total antioxidant capacity (1.49 ± 0.27 vs. 1.66 ± 0.27 mmol trolox equivalent/L, p= .008) compared with the controls. In addition, OA group had significantly higher level of C-peptide compared with the controls [1.8 (0.94-2.47) vs. 1.3 (0.46-1.42) ng/mL, p < .001, respectively]. Furthermore, OA radiographic severity was independently associated with LDL-cholesterol (p = .007) and oxidized LDL (p = .022). This study demonstrates that end-stage OA patients have increased levels of OxS and decreased antioxidant capacity. OA is associated with impaired lipid metabolism and dysglycemia. Our results underline the importance OxS and metabolic disturbances in the pathogenesis of OA.