Evaluation of Paraoxonase-1 Activity of Arylesterase and Lactonase and Their Correlation with Oxidative Stress in Children with Type 1 Diabetes Mellitus

Abstract

Background: Type 1 diabetes mellitus (T1DM) is a chronic autoimmune condition that can lead to long-term complications due to oxidative stress and metabolic dysregulation. Paraoxonase-1 (PON-1), an enzyme associated with high-density lipoprotein (HDL), has dual activities: arylesterase and lactonase. These activities protect lipids from oxidative damage. The functional status of PON-1 in children with T1DM may provide insights into the relationship between oxidative stress and the enzyme’s protective role. This study aims to assess the arylesterase and lactonase activities of PON-1 in Iraqi children with T1DM. Methods: Sixty-seven children with T1DM were enrolled and compared with 57 age-matched healthy controls. The enzymatic activities of arylesterase and lactonase were measured to evaluate PON-1’s functional status. The Paraoxonase-1/HDL (PON/HDL) ratio was calculated to assess lipid protection and antioxidant capacity. Oxidative status was assessed by measuring total oxidative status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI). Results: PON-1 activity analysis showed a significant reduction in arylesterase (2.36 ± 1.17) and lactonase (21.9 ± 7.31) in the patients group compared to controls (arylesterase=4.54 ± 1.84, lactonase =29.51 ± 9.92). TOS and OSI were significantly higher, while TAS was significantly lower in the patients group. Pearson correlation revealed a positive correlation between HDL-C and arylesterase (P = 0.002, r = 0.379), and HDL-C and lactonase (P = 0.040, r = 0.366). Conclusion: Reduced PON-1 activity is associated with T1DM, suggesting that enhancing PON-1 or reducing oxidative stress may help prevent diabetic complications and improve cardiovascular health.