engleski

RELATIONSHIP BETWEEN PARAOXONASE 1 ACTIVITY AND HDL CONCENTRATION DURING NATURALLY OCCURRING BABESIOSIS IN DOGS

Paraoxonase 1 (PON1) is a negative acute phase protein, that circulates in blood bound to high density lipoproteins (HDLs) and exerts an antioxidant function. Specifically, during systemic inflammation, the Reactive Oxygen Species (ROS) produced against pathogens leads to lipid peroxidation converting HDL to LDL. Consequently, PON1 detaches from HDL and reconvert LDLs to HDLs. Therefore, its serum activity decreases due to an increased consumption Aim of this study is to assess the antioxidant role of PON1 towards HDL, using, as a model, dogs naturally affected by babesiosis (a disease on which changes on the serum concentration of HDL has already been demonstrated) and to assess the changes of PON1 activity and HDL concentration during the course of the disease. To this aim, serum from 30 dogs infected by Babesia canis were sampled at admission (day 0) and on day 1 and 6. 15 control dogs were also included in the study to assess the actual presence of altered HDL and PON1 at day 0. PON1 and HDL were measured on all the samples using methods already validated on canine serum. Compared with controls, both the serum concentration of HDL and PON1 activity were significantly low at day 0. The concentration of HDL significantly increased at day 1 and day 6 compared with day 0 (p<0.05 for both) without significant differences between days 1 and 6. PON1 activity did not differ between day 0 and day 1 but significantly increased on day 6 compared with day 0 and day 1 (p < 0.001 for both). These results support the hypothesis that PON1 exerts an antioxidant role towards HDL also in dogs. The low serum concentration of HDL at admission is consistent with lipid peroxidation. The earlier increase of HDL (day 1) compared to PON1 (day 6) is probably dependent on increased consumption of PON1 on day 1 to reduce the oxidized lipids and to quickly restore the concentration of HDL.

PON-1; HDL; babesiosis

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