Harbingers of neonatal birth weight: The PON1 arylesterase and lactonase activities

Objective: An important predictor for infant survival is birth weight. Normal fetal growth is related to various intrauterine factors. Low birth weight is thought to have relation with oxidative stress which plays an important role in reducing the birth weight. Among the paraoxonase family PON1 protects LDL and HDL from the lipid peroxidation. This is HDL associated enzyme having antioxidant property. We aimed to evaluate the arylesterase and lactonase activity of PON1 in cord blood in relation to birth weight. We hypothesized that cord blood PON1 arylesterase and lactonase activities will be compromised in neonates having low birth weight. Methods: We included 80 neonates born in our hospital irrespective of mode of delivery as 40 cases and 40 controls. PON1 arylesterase and lactonase activity were measured using spectrophotometer. Results: Serum arylesterase activity decreased significantly in low birth weight babies (p<0.05). Linear regression analysis (R=0.595) indicates significant correlation between arylesterase and birth weight. Serum lactonase activity of PON1 also gets reduced in low birth weight babies. Its linear regression analysis showed (R=0.716) suggesting significant correlation between lactonase and birth weight. Conclusion: Reduced PON1 activity can be explained on the basis of ER stress and atherogenic changes in the placental circulation. Ours is the first study in cord blood paraoxonase activities in relation to birth weight. As the sample in our study is cord blood, it is essentially a noninvasive one. Further studies are needed in this direction to assess the effect of the oxidative stress on fetus through cord blood in its long term prospective.