Study of Serum Paraoxonase and High Density Lipoprotein Fractions in Diabetes

Significant alteration in lipid profile and antioxidant system occurs in response to diabetes mellitus (DM). Paraoxonase (PON) is a family of three enzymes PON1, PON2 and PON3 associated with high density lipoprotein (HDL). The HDL in human plasma consists of two main sub-fractions HDL2C and HDL3C. We studied the HDL subclasses and HDL associated enzyme paraoxonase with respect to diabetes.
The study was conducted in a tertiary care referral hospital in India. A total of 80 subjects were included in the study. Lipid profile, PON1 arylesterase (ARE), PON1 lactonase (LACT) and HDL fractions were estimated. Regression analysis was applied.
PON1 ARE, LACT and HDL fractions are found to be decreased among cases than in controls. PON1 ARE & LACT showed negative correlation with blood glucose levels and HDL 3C while positive correlation with HDL 2C.
PON1 ARE and PON1 LACT activities reduction are due to increased oxidative stress. PON1 as well as HDL fraction levels are oxidative stress subjects. Among the HDL fractions, HDL2C is the more variable fraction and reflects changes in HDL. The study suggested that the protective role of total HDL against oxidative damage and complications is mainly mediated through HDL2C fraction.