According to a new study published in The Lancet, privately funded and led by UCLA and Advanced Cell Technology researchers, two women suffering a progressive form of blindness have shown improved vision.
Stem cell pioneer James Thomson of Cellular Dynamics International who headed the University of Wisconsin team that in 1998 first isolated human embryonic stem cells (ES) spoke on the development. ES are the master cells from which all other tissues in the body differentiate during development. Since 2006, Thomson has also been a leader in human induced pluripotent stem cell (iPS) research, looking at how these adult cells can be transformed into ones resembling ES cells. “I've always thought that the transplantation of ES or iPS cell derivatives would be extremely challenging, and that the press has over-hyped the possibility of success in the short term. However, the transplantation of retinal pigmented epithelium for the treatment of certain forms of blindness is, I believe, a possible exception. I'm more familiar with the work being done by the CIRM funded California Project to Cure Blindness than the work performed by ACT, but it is an area that shows real promise. Although the initial work has been done with human ES cells, it is an area where human iPS cells will be useful if the transplanted cells are attacked by the immune system,” he said to USA Today.
ACT's Robert Lanza, senior author on The Lancet study, says the team hopes to shift to iPS studies in future clinical trials for just that reason, however medical researchers need to establish the safety of plutipotent human embryonic stem cell treatments in medical tests, before moving on to iPS cells.
Writing in The Lancet medical journal this week, Dr Lanza and his colleagues said if the treatment was proven to be safe and effective in more patients over time, the stem cells could be used early in the disease process to improve the prospects of people retaining their sight. “It has been over a decade since the discovery of human embryonic stem cells,” he 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 (age-related macular degeneration), no proven treatments currently exist for either dry-AMD or Stargardt's disease,” he said.
In 2006, ACT developed a “single-cell biopsy” method to remove a lone cell from an embryo, leaving it otherwise intact and viable, and then use that single cell to generate stem cells in laboratory research colonies. “Yes, we used the single-cell biopsy method (but we discarded the embryo afterwards). However, we have several hESC (human embryonic stem cell) lines where the embryos were not destroyed - we plan to switch to those hESC lines in future (phase 3/4) clinical trials,” Lanza said.
“This really is a landmark study,” said stem cell biologist Paul Tesar of Case Western Reserve University in Cleveland, who was not part of the research. Although the firm, Geron Corp. of Menlo Park, Calif., pulled out of human embryonic stem cell research last fall, the ACT results look promising for the field he says. “The eye turns out to be a really good place to check for safety with this therapy,” he says.
Professor of Stem Cell Science at The University of Melbourne, Martin Pera, described the trial as a “landmark study”, given it was the first published account of a human trial of embryonic stem cell-based therapy. “It will soon be clear whether these preliminary results are a harbinger of a new era in cell therapy for this devastating medical condition,” he said.
The controversial development could provide hope for hundreds of thousands of people suffering from macular degeneration - one of the most common forms of blindness in developed countries. According to the Macular Degeneration Foundation, one in every seven Australians over 50 is affected in some way and the incidence increases with age.
There are biological risks that come with their use, including teratoma formation, a type of cancer that occurs when stem cells differentiate into multiple cell types and form incompatible tissues that can include teeth and hair.