Source: EUROPEAN PATENT EP 2 433 640 A1
In developed countries, the most frequent causes of visual incapacities or blindness are diseases, such as for example age-related macular degeneration (AMD), diabetic retinopathies (DR), cataract and retinitis pigmentosa (RP). These different ocular pathologies present the common characteristic to be associated with oxidative stress. Oxidative stress corresponds to an excess of oxidant elements as compared to antioxidant products, resulting in structural or formal damages, such as cellular damages. Moreover, with ageing, antioxidant defenses decrease, in particular in the eye.
In human, antioxidant protection involves two major types of elements: enzymes or non-enzymatic products. Three major antioxidant enzymes are present in human cells: glutathione reductase and peroxydase (GPX), superoxide dismutase (SOD) and catalase (CAT). The combination of the action of these three enzymes leads to the transformation of highly toxic superoxide ion to hydrogen peroxide (H2O2) and finally to water. In parallel to enzymatic protection of cells against oxidative stress, some non-enzymatic products exist. For example, vitamins (A, E or C), lutein and zeaxanthin are usually used for their antioxidant properties.
A form of SOD protected by gliadin is available as GliSODin® (Isocell). The catalytic activity of SOD protected by gliadin is preserved during oral administration, allowing its administration through an oral way. The invention also relates to a method for preventing, stabilizing or treating a retinal pathology, preferably a retinal pathology associated with oxidative stress, comprising administering to a subject in need thereof a composition or a kit of parts comprising SOD, preferably SOD micro-encapsulated with gliadin, lutein and at least one zeaxanthin isomer.