Living Corneal Stem Cell Donors
Former model, Katie Piper, recently had stem cell treatment on her eye three years after an acid attack nearly blinded her.
Results of Stem Cell Transplant for Corneal Damage
Patients had the abnormal scar tissue across the cornea removed prior to the transplantation of limbal conjunctival tissue from their closest matched living relative. All patients had immunosuppressive drugs to reduce the risk of tissue rejection and their progress was monitored for an average of 26months after the stem cell transplant. Daya and Ilari were looking for signs of corneal epithelum restoration, reduced growth of abnormal blood vessels and conjunctiva, and any improvement in comfort, corneal clarity, and visual acuity. Two of the treated eyes were severely inflamed and epithelial growth did not occur. The other treated eyes maintained the transplanted cells and corneal epithelium restoration occurred along with reduce vascularization.
Clearer Corneas for Clearer Vision Using Stem Cells
Half of the eyes treated (4/8) using limbal conjunctival transplants developed clearer corneas, and resulting visual improvement occurred in seven eyes. All of those patients experiencing eye-pain had symptom improvement following the stem cell surgery. Two of the eyes damaged due to Stevens-Johnson syndrome, and which received transplants with class I human leukocyte antigen differences, experienced allograft rejection. This was treated successfully in both cases. None of the donors experienced complications and the study’s authors concluded that the stem cell transplant from living donors with simultaneous immunosuppressant use is a promising tool for vision restoration in limbal stem cell deficiency.
Limbal Stem Cell Deficiency Correction with Transplant
Daya and colleagues (2005) then set out to examine the use of cultured stem cell allografts for resurfacing and reconstructing the eye’s cornea, as well as analysing the residual DNA from the donor of the stem cells after transplantation. Their hope was to build on their success in using material transplanted from living, matched donors and increase the potential access to the treatment where a living related donor was not readily available.
Stem Cell Deficiency Correction
Using ten subjects in the study, all with severe limbal stem cell deficiency (LCSD), Daya, et al, removed the patients’ damaged conjunctival pannus (abnormal surface) and grafted the cultured sheets of allogeneic corneal limbal stem cells onto the eye. The patients’ then had an amniotic membrane (taken from the lining of the womb) used as a bandage over the transplanted cells to encourage cell growth. Nine of the patients were given immunosuppressive medication (cyclosporin A) to reduce the risks of transplant rejection. Analysis after nine months showed no residual DNA from the donor which may mean that long-term immunosuppression in corneal transplant is unnecessary.
Eye Disease and Stem Cells
Patients treated during Daya’s 2005 study suffered from a variety of injuries and diseases of the eyes. Three has ectodermal dysplasia, three suffered from Stevens-Johnson syndrome, two had experienced chemical injuries to the eye and one a thermal injury, and the last of the ten patients had rosacea blepharoconjuncitivits, making the stem cell treatment for visual loss a potential strategy for a variety of conditions. The patients were assessed for blood vessel development, conjunctivalization, inflammation, light-sensitivity, eye pain, and epithelial defect after the transplants.
Results of Stem Cell Transplants
Follow-up continued for a year to four years across the patients and 70% of the eyes treated showed improvement at final follow-up. 40% of patients experienced improvements in vision whilst three had no improvement. Those failing to improve included the patient with thermal burn and eyelid deformity, one with Stevens-Johnson syndrome (and dry eye), and the patient with ectodermal dysplasia. Such results may help doctors decide who is a potential candidate for stem cell transplants for vision loss.
