YORKSHIRE, England, Jan. 23 (UPI) -- A controversial transplant of stem cells derived from a human embryo may result in some vision improvement for three blind test subjects, U.S. researchers said.
The first two patients, who are Americans, each received transplants in one of their eyes last year. They have not shown any signs of serious side effects, such as tissue rejection or the development of tumors, The Independent reported.
One patient, a woman in her 50s, suffers from Stargardt's macular dystrophy, an eye disease of the central retina that usually strikes between ages 10 and 20. The second subject, a woman in her 70s, has age-related macular degeneration, the leading cause of blindness in the developed world.
A patient from Yorkshire, England, had a similar procedure last week involving the injection of embryonic stem cells into the damaged retina at the back of the eye, The Independent said.
Both U.S. patients have exceptionally poor vision and are legally registered as blind, but their sight in the treated eye seems to have improved slightly following the transplants -- even though their disease is at an advanced stage and they were not expected to recover.
"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," Robert Lanza, chief scientific officer of Advanced Cell Technology, the Massachusetts company that supplied the stem cells, told the Independent.
The findings were published online in The Lancet.
