The role of free oxygen radicals in the aetiopathogenesis of rosacea

Abstract

A possible link between superoxide dismutase activity and malondialdehyde level with the clinical manifestations of rosacea was investigated. We found differences in superoxide dismutase activities between mild rosacea (stages I and II) and severe involvement (stage III) groups, as well as between disease and control groups that were statistically significant (P < 0.05). In the mild involvement group (stages I and II), the superoxide dismutase activity was higher than in the control group (P < 0.05), while the malondialdehyde levels did not differ from the control. In the severe involvement group (stage III), the superoxide dismutase activity was lower than in the control group (P < 0.05), and this was coupled to a raised level of malondialdehyde (P < 0.05). These findings clearly show that in the mild involvement phase of rosacea patients, superoxide dismutase activity was stimulated to protect the skin against reactive oxygen species so that the malondialdehyde levels were maintained. In contrast, in more severe disease, due to a decrease in the capacity of the antioxidant defence system, the malondialdehyde levels were increased. These findings support the 'antioxidant system defect hypothesis' in rosacea patients.

Rosacea: An Update

“…Skin naturally uses antioxidants to protect itself from photodamage. Recent findings support the hypothesis that antioxidant protection is decreased in patients with rosacea [20]. …”

Tetracycline Actions Relevant to Rosacea Treatment

“…These findings support the 'antioxidant system defect hypothesis' in rosacea patients, i.e. a reduced capacity to counter the negative effects of ROS, thus experiencing an increased inflammatory response [13,14] . This may also explain the pathogenetic association between rosacea and photodamage, since long-term sun exposure is known to cause an increased generation of ROS, which, in turn, subsequently activate MMPs and in this way trigger the inflammation pathway [13,31] .…”

“…Furthermore, markers of the antioxidant defense system are inversely correlated to the clinical manifestations of rosacea. This means that in patients with mild rosacea (stage I or II) the superoxide dismutase activity was higher than in healthy controls while the malondialdehyde level (a biomarker for oxidative stress [79] ) did not differ from controls, whereas in the severe involvement group (rosacea stage III) the superoxide dismutase activity was lower than in the control group coupled to an increased level of malondialdehyde [14] . These findings suggest that in mild rosacea the antioxidant defense system is activated in order to keep the ROS levels constant.…”

“…Anyway, 2 further mediators of inflammation, reactive oxygen species (ROS) and nitric oxide (NO), have been shown to play a role in rosacea pathophysiology [12,13] . It has in particular been shown that patients with severe rosacea have an impaired defense capacity against the proinflammatory and damaging effects of ROS [11,14] . Reactive nitrogen intermediates like NO in turn are responsible for vasodilatation possibly leading to increased vessel permeability and edema and supporting erythema and telangiectasia [11] .…”

Decreased arylesterase activity and increased total oxidative status in rosacea

“…Reactive oxygen species (ROS) and SOD levels were determined. In rosacea lesions, there was a higher ROS activity and a lower SOD level when compared to the controls [6]. The inhibition of ROS activity in neutrophils with various topical and systemic drugs used in the treatment of rosacea supports the "oxidative stress phenomenon" hypothesis [7][8][9].…”