Umbilical stem cells could treat cloudy cornea

New research offers promise of restoring vision in patients with congenital or acquired corneal scarring. The findings were presented at the 49th Annual Meeting of the American Society of Cell Biology in San Diego, US.

The cornea is a transparent part of the front of the eye important for focusing light and protecting underlying structures. Disease or injury can cause scarring, impairing vision. Professor Winston Whei-Yang Kao and members of his team at the University of Cincinnati's ophthalmology department transplanted stem cells derived from the human umbilical cord into the corneas of mice with cloudy, thin corneas. The mice had been bred to lack a protein, lumican, which is important for transparency the cornea. Mice lacking lumican mimic the human condition.

Following transplantation, the corneas of the treated mice significantly improved their transparency. Furthermore, the transplanted cells were still present after three months and appeared to have assumed the properties of normal corneal cells called keratocytes. 'Our results suggest a potential treatment regimen for congenital and/or acquired corneal diseases. These stem cells are easy to isolate and can be recovered quickly from storage when treating patients' Professor Kao said. He added that the availability of human umbilical cord blood stem cells is almost unlimited. 'These findings have the potential to create new and better treatments - and an improved quality of life-for patients with vision loss due to corneal injury,' he said.

Currently only corneal transplantation is able to restore eyesight lost due to corneal scarring. However, Professor Kao explained that 'the number of donated corneas suitable for transplantation is decreasing as the number of individuals receiving refractive surgeries, like LASIK, increases'. He added: 'Worldwide, there is a shortage of suitable corneas for transplantation, and at the present time, there is no effective alternative procedure besides corneal transplantation to treat corneal blindness. There is a large need to develop alternative treatment regimens, one of which may be the transplantation of mesenchymal stem cells'.

Dr Francisco Arnalich, a researcher from Moorfields Eye Hospital in London who has carried out similar work in rabbits, explains: 'There is still a long way to go from saying that they achieved clear corneas - moreover they just state that they improved transparency, not that they reach normal transparency - to say that this could be a substitute of corneal grafting'.