Oxidative Stress in Patients With Age-Related Macular Degeneration
First, to quantify, by means of comet assay analysis, systemic oxidative stress in patients with non-exudative and exudative age-related macular degeneration (AMD) and compare results to healthy controls.
Second, to quantify systemic oxidative stress in patients with exudative AMD prior to and after photodynamic (PDT) therapy.
|Study Design:||Observational Model: Case-Only
Time Perspective: Prospective
|Official Title:||Quantification of Oxidative Stress in Patients With Age-Related Macular Degeneration Prior to and After Photodynamic Therapy: a Comet Assay Analysis|
|Study Start Date:||November 2006|
|Study Completion Date:||December 2007|
|Primary Completion Date:||December 2007 (Final data collection date for primary outcome measure)|
Oxidative stress is the major factor that plays a role in the pathogenesis of age-related macular degeneration (AMD), which is a leading cause of blind registration in the developed world. The term oxidative stress refers to reversible damage to molecules, such as for example DNA, by reactive forms of oxygen (eg. free oxygen radicals). This damage is repaired is normally repaired in our body.
AMD is classified in two forms: the dry (non-exudative) and wet (exudative) form. The exudative form of AMD occurs when new blood vessels form to improve the blood supply to retinal tissue. However, the new blood vessels are very delicate and break easily, causing bleeding and serious vision loss. The standardized method used to treat exudative AMD is photodynamic therapy (PDT). This treatment is based upon the infusion of a drug that can be activated by light and produces free radicals that destroy these newly formed vessels. In other words, these new vessels are destroyed by an iatrogenic source of oxidative stress. This means that the factor that originally caused the disease AMD, namely oxidative stress, is finally used as a form of treatment- to destroy these newly formed blood vessels.
In the present study we would like to quantify in a first step the level of systemic oxidative stress in patients with non-exudative and exudative AMD and compare to healthy controls. In a second step we would like to test whether the treatment (PDT) for patients with exudative AMD additionally increases systemic oxidative stress. Oxidative stress is quantified in our laboratory by means of single cell gel electrophoresis or comet assay.