Non-pharmacological interventional perspectives in AMD

Transplantation and translocation surgery for the treatment of AMD has been evaluated for over 25 years. More recently injections of inhibitors of vascularisation have been used with some success. Inhibitors of neovascularisation result in the recovery of vision in about 30% of patients; however, we do not understand what criteria can be used to select patients who will respond to or will not respond to treatment with antivascularisation treatment. We have to assume that Successful antivascularisation treatment will require first that the retinal pigment epithelial cells be present and functional and second that the photoreceptor cells should not be degenerated. We then hypothesise that if either of these two parameters are not present, antivascular treatment will not result in vision recovery and we must then consider surgical intervention. Surgical intervention for macular degeneration encompasses procedures from simple membrane extraction to macular rotation to cell transplantation or a combination of these procedures, however these procedures must take into account that vision recovery cannot be achieved without reconstruction of the retina-choroid complex. Since in AMD degeneration of the retinal pigment epithelial cells and vascular membranes removal results in damage to the basal lamina and possibly deeper layers of Bruch's membrane, it will be necessary to reconstruct these damaged structures. In fact, transplantation of RPE cells or IPE cells has not resulted in any significant improvement in vision in AMD patients. Longterm follow-up of AMD patients following macular rotation surgery has shown that significant visual recovery is not maintained in most patients. Of the many approaches that could be used to reconstruct the damaged basal lamina and Bruch's membrane the most promising would be the introduction of a monolayer of pigment cells on a "natural" biodegradable Substratum. A natural substratum consisting of extracellular matrix proteins Would allow the pigment cells to retain their differentiated characteristics and functions, including the degradation the Substratum and production of the normal components of the basal lamina and Bruch's membrane. In addition, the cells introduced as a monolayer can be engineered to carry specific genes to aid in the restructuring of the retina-choroid complex, such as growth factors and inhibitors of vascularisation.