Endocrine Abstracts

Background: Serum paraoxonase-1 (PON-1) activity is decreased in clinical conditions associated with low high density-cholesterol (HDL-C), increased lipid peroxidation and low-grade chronic inflammation such as in type 2 diabetes mellitus (T2DM). Although many studies have shown that some poly unsaturated fatty acids (PUFA) modulate cardiovascular risk in T2DM, until now there is no data about the association of any fatty acid (FA) with PON-1 activity. This study aims to investigate this field.

Materials and methods: The 20 consenting adult T2DM patients, and 16 healthy controls were included in this cross-sectional study. Serum PON-1 activity, was measured together with other anti-oxidative enzymes activity, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), as well as plasma glucose level, HbA1c, lipids, high sensitive C-reactive protein (hs-CRP) and insulin resistance, homeostasis model assessment (HOMA-IR). The extraction and preparation of FA methyl esters and their GC analysis were performed too.

Results: HbA1c, plasma insulin, HOMA-IR and triglycerides were significantly higher in T2DM patients, whereas HDL-C was lower in those subjects. The levels of pro-oxidative enzyme malonildialdehyde (MDA), and the marker of chronic inflammation hs-CRP, were significantly higher in plasma of T2DM patients, and on contrary anti-oxidative enzymes SOD, and PON-1 activity were decreased in T2DM patients. Total PUFA and n-6 PUFA were significantly higher in T2DM patients, particularly linoleic acid (LA, 18:2 n-6) and arachidonic acid (AA, 20:4 n-6), whereas n-3 PUFA, particularly docosahexaenoic acid (DHA, 22:6 n-3) were significantly lower in T2DM patients. Stepwise multiple regression analysis have shown that only LA and DHA, independently predicted PON-1 activity of our subjects. LA, DHA and the presence of T2DM explained 70% of variance in PON-1 activity.

Conclusions: We have shown that decreased serum PON-1 activity may be in part influenced by higher level of LA and lower level of DHA in T2DM patients.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.