Human Optic Cup Grown From Stem Cells
From Nature: researchers have "grown the precursor of a human eye in the lab. The structure, called an optic cup, is 550 micrometres in diameter and contains multiple layers of retinal cells including photoreceptors. The achievement has raised hopes that doctors may one day be able to repair damaged eyes in the clinic. ... the most exciting thing is that the optic cup developed its structure without guidance from [the] team. ... Until recently, stem-cell biologists had been able to grow embryonic stem-cells only into two-dimensional sheets. But over the past four years, [this group] has used mouse embryonic stem cells to grow well-organized, three-dimensional cerebral-cortex, pituitary-gland and optic-cup tissue. His latest result marks the first time that anyone has managed a similar feat using human cells. ... The various parts of the human optic cup grew in mostly the same order as those in the mouse optic cup. This reconfirms a biological lesson: the cues for this complex formation come from inside the cell, rather than relying on external triggers. ... retinal precursor cells spontaneously formed a ball of epithelial tissue cells and then bulged outwards to form a bubble called an eye vesicle. That pliable structure then folded back on itself to form a pouch, creating the optic cup with an outer wall (the retinal epithelium) and an inner wall comprising layers of retinal cells including photoreceptors, bipolar cells and ganglion cells. ... This resolves a long debate [over] whether the development of the optic cup is driven by internal or external cues."
Link: http://www.nature.com/news/biologists-grow-human-eye-precursor-from-stem-cells-1.10835