Oxystat technique in study of reactive oxygen species

Hypotensive effect of atorvastatin is not related to changes in inflammation and oxidative stress

We sought to determine if atorvastatin lowers blood pressure in patients with previously diagnosed and well-controlled essential arterial hypertension and if this effect could be related to anti-inflammatory and anti-oxidative effects. Among 92 patients with essential arterial hypertension, we studied 56 non-smoking and normolipemic: 39 were randomized to receive 80 mg atorvastatin daily for 3 months (statin-treated patients, ST), and the rest continued a previous hypotensive therapy (statin-free patients, SF). Blood pressure was measured using a 24-h ambulatory blood pressure measurement device. Serum levels of high-sensitivity C-reactive protein (hs-CRP), total antioxidant status (TAS) and plasma peroxides (assessed by Oxystat) were measured in both groups. The mean change in systolic BP (SBP) for atorvastatin was -5.7 mmHg (95% confidence interval CI, -4.1 to -7.2 mmHg), and the mean change in diastolic BP (DBP) was -3.9 mmHg (95% CI, -2.7 to -5.0 mmHg). No change in BP in SF patients was observed. In the ST group, hs-CRP and peroxides did not significantly decrease. In the SF group, concentrations of hs-CRP proceeded to decrease while peroxides increased. In the ST group, changes in hs-CRP correlated with changes in total cholesterol and low-density lipoprotein cholesterol (r = 0.41, p = 0.013 and r = 0.35, p = 0.04, respectively) but did not correlate with changes in BP. The hypotensive statin effect was independent of the hypolipemic effect. During three months of observation, TAS concentrations in both groups remained stable. In this randomized study, additionally administered atorvastatin to non-smoking and normolipemic patients with well-controlled essential arterial hypertension resulted in reduction of BP. This effect was not followed by significant changes in hs-CRP, TAS or Oxystat concentrations. The hypotensive effect of atorvastatin did not depend on anti-inflammatory, anti-oxidative or hypolipemic actions.

Direct and indirect measurements of oxygen radicals

Instead of covering the available detection methods in detail it is attempted to highlight the ambiguities inherent in oxygen radical detection under in vivo conditions. Due to physicochemical properties of the oxygen molecule, all organic matter is bound to autoxidize. From this it follows that a certain 'background' level of oxygen radical production will always be present and that it may be difficult to differentiate between inherent and induced oxygen radical production. Radicals by their very nature react 'unspecifically'. This infers that it is difficult to identify them unequivocally. The most common methods for oxygen radical detection are briefly mentioned.