Corneal Disorders Treated Using Novel Adult Stem Cell Method
Basque Research, July 22, 2007
Cornea stem cell growth was demonstrated by a new technique at the Area of Cellular Therapy of the University Clinic (University of Navarra). Researchers demonstrated the efficacy of adult stem cells in this capacity.
70 rabbits, which served as test animals, were treated for diseases of the cornea using stem cells. The technique was developed by Dr. Ana Fernández Hortelano, who is an ophthalmologist at the hospital. Restoring the transparency of the cornea by regaining the damaged epithelium was the aim of the procedure.
The thesis that austications or ocular herpes can derive therapeutic benefit from treatment using stem cells from a healthy contralateral eye was defended by doctor Fernández Hortelano at the Faculty of Medicine of the University of Navarra. He proved the therapeutic efficiency in using corneal stem cells in patients with pathologies of the cornea. Satisfactory results have been achieved in patients who have recently undergone the procedure.
The research has two essential parts. The clinical application of the procedure is explained in one part and the other side of the coin describes the design of a new method of cell growth.
To the point of obtaining levels for the treatment to be effective, the new growth technique enables the growth of a sufficient number of stem cells from a small biopsy sample. A sample is taken from the ocular structure in the healthy eye that is responsible for the transparency of the cornea. This structure is called the limb.
The importance of this growth method lies in the fact that it enables the characterization of the cells obtained, i.e. determining the quantity and viability of the units to be used.
The method developed combines an amniotic membrane culture and a limbal cell culture on a plastic chip. Where the plastic chip is used in the first stage is where the novel approach of the technique focuses. Grown on the chip are smaller dividing fractions of the fragment of tissue obtained from the healthy eye. This process yields a greater number, as many as the fragments of tissue, of halos of stem cells. The quality and viability of the cell units are verified by sending the sample to the Anatomic Pathology laboratory.
The cells are transferred to the amniotic membrane growth culture, one that is highly suitable when dealing with stem cells that are to be transplanted for ocular regeneration treatment.
Enabling a better cell identification in order to select the most suitable units for the treatment, the stem cells expand in a homogeneous manner one in the amniotic membrane. Both the quantity and the quality of the cells transplanted into the eye are verified with precision using this method.
The loss of corneal transparency was induced by an epithelial corneal lesion in rabbits. These animals were involved in the second part of the research where adult stem cells were transplanted into the rabbits to determine clinical applications. This pathology does not respond to a corneal transplant nor to other conventional treatment.
By means of a biopsy of cells from a healthy eye of the rabbit, Dr Fernández Hortelano is able to extract corneal stem cells. So the contrateral eye is not in danger, the sample of cells is small; only 3 by 4 mm. An expansion is later achieved by transferring the culture to the amniotic membrane. Thus the tiny number of cells involved grows into a greater number of cells that can then be used for clinical application.
The transparency of the cornea is restored as the corneal epithelium recovers. The limb is regenerated in the damaged eye by implanting the adult stem cells.
60% of the treated animals with induced limbic insufficiency showed recovery of the corneal epithelium after a transplant of adult stem cells.
The problem of opacity of the cornea is due to the limbic insufficiency which leads to a damaged corneal epithelium layer. Adult stem cells can rejuvenate the limbic cells and lead to the restoration of the cornea.