Blind Patients Can See Better

A controversial trial treatment for vision loss using human embryonic stem cells has produced “ground-breaking” early results, it has been claimed.

Two “legally blind” patients with different forms of macular degeneration – one old and one middle-aged – showed signs of improved vision four months after receiving the implants, said scientists.

One, a woman in her fifties suffering from Stargardt’s disease, went from being unable to read any letters in a standard eye test to reading five letters. She was also able to spot single-finger movements whereas before she could only discern movements of the whole hand.

The other patient, a woman in her 70s with dry age-related macular degeneration, experienced an improvement that allowed her to read 28 rather than 21 letters. Neither patient appeared to have suffered any serious adverse affects from the therapy, such as teratoma – a form of cancer that can be generated by multiplying stem cells.

The results, from a trial being conducted in the US, appear in the latest issue of The Lancet medical journal.

The two women were given transplants of retinal tissue grown in the laboratory from human embryonic stem cells (hESCs). In each patient, around 50,000 of the cells, called retinal pigment epithelium (RPE) cells, were injected through a thin tube into the back of one eye.

Embryonic stem cells offer the hope of promising regenerative treatments because they can differentiate into any kind of tissue in the body, from brain to bone. Human ESCs can be grown continuously in the laboratory but are controversial because they must originally be obtained from early-stage human embryos.

Dr Robert Lanza, from the US biotech company Advanced Cell Technology in Marlborough, Massachusetts, who led the study, said: “This is the first report of hESC-derived cells ever transplanted into patients, and the safety and engraftment data to date looks very encouraging.

“Although several new drugs are available for the treatment of the wet type of AMD, no proven treatments currently exist for either dry-AMD or Stargardt’s disease. Despite the progressive nature of these conditions, the vision of both patients appears to have improved after transplantation of the cells, even at the lowest dosage.”

Commenting on the new findings, British expert Professor Daniel Brison, co-director of the North West Embryonic Stem Cell Centre in Manchester, said: “This is a very exciting moment for embryonic stem cell therapies. This is the first peer-reviewed scientific report showing that cells derived from human ES cells can be transplanted safely into a patient with no sign of complications.”