Mesenchymal Stem Cells in the Eye

Hyderabad, India -

Mesenchymal stem cells are one of the most clinically advanced forms of stem cell therapy after hematopoietic stem cell transplantation.  The conventional source for mesenchymal stem cells has been bone marrow, however these cells can also be extracted from a variety of other tissues such as teeth, placenta, cord blood, and menstrual blood.

A recent publication (Polisetty et al. Mesenchymal cells from limbal stroma of human eye. Mol Vis. 2008 Mar 4;14:431-42) describes mesenchymal stem cells found in the limbus of the human eye. 

The investigators collected limbal tissues from patient biopsy samples during eye surgery.  Cells with a spindle-like morphology were expanded as adherent cells in a medium containing EGF, insulin, and fetal calf serum. 

The "mesenchymal" cells expanded from the limbus possessed a similar phenotype to bone marrow derived mesenchymal stem cells.  For example, they expressed CD90, CD105, and CD29 and lacked expression of CD34, and CD45.  Additionally, the limbal derived mesenchymal cells were capable of differentiating into bone, fat and cartilage tissue.

The identification of various subsets of stem cells in the human limbus is important since clinically limbal stem cell transplants have been performed with some degree of success.  For example, a paper from 1999 (Tsubota et al. Treatment of severe ocular-surface disorders with corneal epithelial stem-cell transplantation. N Engl J Med 1999 Jun 3;340(22):1697-703) describes 70 corneal epithelial stem cell transplants, in which a statistically significant improvement in vision was observed.