[Intravenous oxygen therapy increases the activity of the antioxidative and antiatherogenic serum enzyme paraoxonase 1].

Background: Intravenous oxygen infusions have been introduced in complementary medicine for treatment of atherosclerosis and inflammatory diseases. As atherosclerosis and inflammation are causally related to oxidative stress and as intravenous supply with oxygen causes oxidative stress, it was suggested that the clinical success of intravenous oxygen therapy is biochemically based on an enhancement of endogenous antioxidative mechanisms. The anti-atherogenic enzyme paraoxonase-1 (PON1) is is part of this system.

Objective: To evaluate the effect of repeated intravenous oxygen infusions on serum PON1 activity.

Patients and methods: A total of 45 patients were treated with intravenous oxygen. During treatment oxygen dosage was increased from 15 to 50 ml (1-2 ml/min). Before treatments 1 and 10 blood was obtained for measurement of PON1 activities. From 20 patients blood was additionally obtained after 20 days of treatment and 2 weeks post treatment. Serum PON1 activity was measured spectrophotometrically using the synthetic substrates paraoxon, phenylacetate, and p-nitrophenyl-acetate.

Results: Using the substrate paraoxon PON1 activity significantly increased by 38% above basal levels 24 hours after intravenous oxygen infusion 9 (p < 0.001). Adverse effects were not observed.

Conclusion: Treatments with intravenous oxygen infusions evoke an adaptation to oxidative stress by an increase of serum PON1 activity. In this regard, a potential molecular mechanism has been found, that explains the protecting effects of intravenous oxygen therapy against oxidative stress and its consequences. PON1 activity is proposed to be an appropriate parameter for monitoring the success of this kind of oxygen therapy.