Lower serum paraoxonase-1 activity is related to linoleic and docosahexanoic fatty acids in type 2 diabetic patients

Serum paraoxonase-1(PON-1) activity is decreased in clinical conditions associated with low high-density lipoprotein cholesterol (HDL-C), increased lipid peroxidation and low-grade chronic inflammation, as in type 2 diabetes mellitus (T2DM). Until now there are no data about the association of any fatty acid (FA) with PON-1 activity in T2DM.

Twenty patients with T2DM and 16 healthy controls were included in this cross-sectional study. Serum PON-1 activity, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity as well as plasma glucose, HbA1c, lipids, high-sensitivity C-reactive protein (hs-CRP) and insulin resistance, homeostasis model assessment (HOMA-IR) were measured. The preparation of FA methyl esters and their gas chromatography (GC) analysis were also performed.

HbA1c, plasma insulin, HOMA-IR and triglycerides were higher in patients with T2DM, whereas HDL-C was lower in those subjects. Levels of pro-oxidative enzyme malondialdehyde (MDA) and hs-CRP were significantly higher, and anti-oxidative enzymes SOD and PON-1 activity were decreased in T2DM patients. N-6 PUFAs were higher in T2DM patients, particularly linoleic acid (LA, 18:2 n-6) and arachidonic acid (AA, 20:4 n-6), whereas n-3 PUFA, docosahexaenoic acid (DHA, 22:6 n-3) was lower in T2DM patients. Using regression analysis, we have shown that only LA and DHA independently predicted PON-1 activity of all participants, particularly in patients with T2DM.

Decreased serum PON-1 activity may, in part, be influenced by higher levels of LA and lower levels of DHA in patients with T2DM. Prospective, randomized studies are necessary to confirm these preliminary findings.