Retinal conditions, degenerative

This condition leads to permanent blindness in about half of cases, and many of those affected are preschool children. Night blindness occurs early in vitamin A deficiency. There is a reduction in rhodopsin concentration, followed by retinal degeneration and loss of photoreceptor cells. Degenerative changes may be due to instability of free opsin or may indicate an additional nutritive function for retinaldehyde (or retinoic acid) in retinal cells. The degenerative changes of retinitis pigmentosa, a relatively common, inherited cause of blindness, closely resemble those of vitamin A deficiency. 

As described below, microdialysis probes have been used to deliver therapeutic concentrations of drugs that may be useful to treat a variety of retinal diseases (50 52). Drugs that target macular edema, syphilis, CMV retinitis, proliferative vitreoretinopathy and retinal degenerative diseases have been tested. However, treatment for other conditions with this approach, particularly intraocular malignancy, could be envisioned. 

Directed differentiation towards retinal lineages has also been investigated for application in cell-based therapies to treat retinopathies and degenerative disorders such as age-related macular dystrophy. The production of retinal cells has recently been reported from ESCs and induced pluripotent stem cells with a cocktail of small molecules in serum-free conditions an ALK inhibitor, a Rho kinase inhibitor and a casein kinase inhibitor. ... 

---