New Treatment Of Disorders Of The Cornea Employing Adult Stem Cell Growth

Main Category: Eye Health / Blindness
Also Included In: Stem Cell Research;  Biology / Biochemistry
Article Date: 23 Jul 2007 - 20:00 PDT

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A new method of adult stem cell growth, designed in the Area of Cellular Therapy of the University Clinic (University of Navarra), has demonstrated its efficacy for its capacity to grow cornea stem cells. So Ana Fernandez Hortelano, ophthalmologist at the Hospital demonstrated on applying the growth technique in treating diseases of the cornea, using stem cells, in 70 test animals (rabbits). The aim of the procedure was to regain the damaged epithelium and thus restore transparency to the cornea.

The thesis, defended by doctor Fernández Hortelano at the Faculty of Medicine of the University of Navarra, proves the therapeutic efficiency of using corneal stem cells in patients with pathologies of the cornea, such as caustications or ocular herpes, by using stem cells from a healthy contralateral eye. The technique is being currently applied to patients with satisfactory results.

The research has two essential parts. On the one hand, it describes the design of a new method of cell growth and, on the other, explains the clinical application of the procedure.

The research undertaken by the ophthalmologist has shown that, from a small biopsy sample, the new technique enables the growth of a number of stem cells sufficient for the treatment to be effective. The cell sample is taken from the limb of the healthy eye -- the ocular structure responsible for the transparency of the cornea.

The importance of this growth method lies in the fact that it enables the characterisation of the cells obtained, i.e. determining the quantity and viability of the units to be used.

The method developed combines culture on a plastic chip with that of pne on an amniotic membrane. The novelty of the technique focuses on the first stage -- where the plastic chip is used. The fragment of tissue obtained from the healthy eye divides into smaller fractions which are grown on the chip. Thus a greater number of halos of stem cells are obtained (as many as the fragments of tissue). A sample of the cells obtained are then sent the Anatomic Pathology laboratory where the viability and quality of the cell units are verified.

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.

Once in the amniotic membrane, the stem cells expand in a homogeneous manner, enabling a better cell identification in order to select the most suitable units for the treatment. This method reveals the cell population that we are implanting in the eye and verifies the quality and quantity of the cells transplanted.

The second part of the research involves the clinical application of the adult stem cells transplanted in rabbits, which previously have had an epithelial corneal lesion induced, causing loss of corneal transparency. This is a pathology that does not respond to a corneal transplant nor to other conventional treatment.

The procedure used by Dr Fernández Hortelano involved obtaining this type of cell -- corneal stem cells -- by means of a biopsy of cells from the healthy eye of the rabbit. This is a small sample of cells -- 3 by 4 mm -- and so the contrateral eye is not in danger. It is then necessary to grow the samples in order to obtain greater numbers of cells, an expansion achieved by transferring the culture to the amniotic membrane.

The adult stem cells obtained are implanted in the damaged eye and the limb is regenerated, leading to the recovery of the corneal epithelium and the transparency of the cornea. The results to date achieved amongst the group of rabbits, with induced limbic insufficiency and which then had a transplant of adult stem cells, showed recovery of the corneal epithelium in 60% of the treated animals. The corneal epithelium is the layer that is damaged with limbic insufficiency, a problem which, in the long term, results in opacity of the cornea.

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Source: Irati Kortabitarte
Elhuyar Fundazioa

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