TGFB1 and age-related macular degeneration: As a result, retinal cells degenerate in the “dry” form of AMD; but sometimes the RPE cells stimulate angiogenic factors (e.g., VEGF, TGFB etc.)which act on the choriocapillary network above the Bruch's membrane and stimulate proliferation of new blood vessels in the areas where blood vessels are not normally present.