Increased PON lactonase activity in morbidly obese patients is associated with impaired lipid profile

The paraoxonase-1 (PON1) enzyme could play an important role in the anti-oxidant capacity of high-density lipoprotein. However, there are no studies which analyse the evolution of the three activities of PON1 (PON arylesterase, PON paraoxonase and PON lactonase) after Roux-en-Y Gastric Bypass (RYGB) in morbidly obese subjects. We analysed the association of PON concentration and activities with the evolution of morbidly obese subjects who underwent RYGB, and its relationship with biochemical variables and different atherogenic indices.

Twenty-seven non-obese and 82 morbidly obese subjects were studied before and 6 months after RYGB.

Before RYGB, morbidly obese subjects had a lower PON1 concentration (P < 0.05) and higher PON lactonase activity (P < 0.001) than non-obese subjects, with no differences in PON arylesterase and PON paraoxonase activities. After RYGB, PON1 concentration (P < 0.05) and PON lactonase activity (P < 0.001) decreased with regard to the presurgery state. PON lactonase activity correlated with the atherogenic index of plasma before (r = 0.19, P = 0.047) and after RYGB (r = 0.27, P = 0.035). In different multiple lineal regression analysis models, presurgery PON lactonase activity was associated with total cholesterol (β = 0.909, P < 0.001), LDL (β = 0.632, P = 0.006) and DBP (β = 0.230, P = 0.030) (R²  = 0.295), postsurgery PON lactonase activity was associated with esterified cholesterol (β = 0.362, P = 0.011) (R²  = 0.131), and the change (Δ) in PON lactonase activity after RYGB was associated with Δesterified cholesterol (β = 0.304, P = 0.030) (R²  = 0.093).

PON lactonase activity is associated with the presence of morbid obesity and with an impaired lipid profile. All associations found could indicate the relationship between PON lactonase activity and the development of atherosclerosis.