A British team of researchers at the Centre for Sight, Queen Victoria Hospital, Sussex has successfully treated more than a dozen patients who had damaged corneas. Of their patients, 10 had completely lost their sight due to getting acid, alkali or burning metal in their eye or had a congenital defect that caused the blindness. Out of this group, seven patients had had their sight restored after stem cells were cultured into a sheet of cells in a laboratory before being transplanted onto the surface of the patient’s eye. Once transplanted, an amniotic membrane was used to keep the cell sheet in place. As the sheet attached itself to the eye, the amniotic membrane dissolved. What doctors and investigators were most stunned by was the fact that the stem cell transplant appeared to activate the eyes own regeneration system. A year after the transplant, doctors were unable to find any DNA from the stem cell donor indicating that it was the patients own eyes that repaired itself. Therefore, the patients did not require the long-term use of potent drugs to help keep them healthy. Additionally, the results are much more likely to be permanent since the patients’ own eyes replaced the stem cells with more resilient cells. Doctors hope to identify exactly how this process works in order to apply it to other organs thereby reducing the need for organ transplants in the future. Sam Lister, Times OnlineApril 22, 2005
Cancer Risk Raises Stem-Cell Doubts
Two separate studies have shown that allowing adult stem cells (those harvested from bone marrow or fat) to grow for too long can potentially result in cancer. In the first study, conducted by Autonomous University of Madrid in Spain, scientists used human stem cells taken from fat tissue and allowed them to grow for eight months in culture. During this time, the cells divided between 90 and 140 times. Once the cells were transplanted to animals, though, the cells that had grown the longest formed cancers. Researchers believe the cancer is the result of the stem cells producing an enzyme, telomerase, which prevents the cell from dying when it normally should thereby resulting in a malignant cell. The second study, done by the University Hospital of Odense in Denmark, scientists found that permanently turning on a cell’s telomerase resulted in cancerous growth. While these findings clearly indicate a need for more research on the effects of using adult stem cells, both research teams pointed out that those adult stem cells that are currently used in therapeutic treatment have either been freshly harvested or have only been allowed to grow outside of the body for a very short period of time. Both studies appear in the journal Cancer Research. Mark Henderson and Leigh Dayton, The AustralianApril 10, 2005
Cord Blood Serum a Better Treatment for Corneal Defects; Study
A study performed at the All India Institute of Medical Sciences has shown that a serum derived from cord blood stem cells can help treat cornea related eye defects. During the study, researchers administered eye drops made of umbilical cord serum. Investigators found that the serum seemed to help the healing of corneal defects. While regular treatment of cornea problems tends to take seven to eight weeks, participants who received the umbilical cord serum had a healing time of two to three weeks. Additionally, although recurrence of the corneal problems is common after typical treatment, researchers found no recurrence of the defects after three months in the participants who received the serum. Source: New Kerala
