BACKGROUND: Malignant pleural mesothelioma (MPM) is the most common cancer in the pleura and highly aggressive with a very poor prognosis. Asbestos, known as a carcinogenic mineral with fiber structures, is the main cause of MPM formation. Exposure to asbestos causes an increase in reactive oxygen species, deficiency of antioxidant enzyme levels, and DNA damage. As a result of asbestos pathogenesis, all of these changes cause pulmonary fibrosis, pleural diseases, and malignancies. The endogenous antioxidant paraoxonase-1 (PON-1) is a calcium-dependent esterase involved in the hydrolysis of lipid peroxides, and PON-1 has been shown to have protective properties in oxidative stress and inflammatory diseases in various studies.
OBJECTIVE: The study aimed to examine the relationship of MPM with PON-1 enzyme activity and oxidative status using total oxidant status (TOS) and total antioxidant status (TAS).
MATERIALS AND METHODS: The study population was formed of 33 retrospectively examined mesothelioma patients as MPM group and 33 age- and sex-matched healthy individuals as controls. PON-1 activity was measured spectrophotometrically by enzyme-linked immunosorbent assay method. Total antioxidant and oxidant status was determined using Rel Assay Diagnostics kit. Oxidative stress index (OSI) was estimated as the ratio of the TOS to the TAS levels.
RESULTS: In the present study, PON-1, TOS, TAS, and OSI levels were adjusted by comorbidity and smoking. The results indicated that TOS and OSI of MPM patients increased compared to healthy controls (P < 0.001 for both). The results also demonstrated the decrease of PON-1 activity and TAS in MPM cases (P < 0.001, for both).
CONCLUSION: These results suggested that oxidative stress occurring as a result of inhalation of asbestos fibers may reduce the level of PON-1.