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Magnetism facilitates migration of cultured endothelial cells to corneal stroma
Invest Ophthalmol Vis Sci. 2009;50(5):2123-2131.
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Use of magnetic particles and a magnetic field safely facilitated attachment of cultured human corneal endothelial cells to the corneal stroma.
“Transplantation of cultured [human corneal endothelial cells] has long been considered a method of expanding the donor pool for endothelial dysfunction, but two obstacles have hindered its development: the ability to culture senescent [human corneal endothelial cells] and the delivery of [human corneal endothelial cells] to the posterior corneal in vivo,” the study authors said.
Human corneal endothelial cell culturing methods have improved, but methods of delivering cultured cells to recipient corneas are lacking, they said.
Investigators incorporated superparamagnetic microspheres into six donor corneas. Three types of superparamagnetic microspheres were used: 900-nm and 300-nm magnetite iron oxide particles, and 100-nm ferumoxide particles. A control group comprised six corneas without superparamagnetic microspheres.
An external magnet was suspended over the culture dish, less than 3 mm above the corneas. Cell viability, cell migration and light transmission were assessed. Investigators aimed to see whether superparamagnetic microsphere-implanted cells would migrate upward, toward the corneal stroma, attracted by the magnetic field.
Results showed that more human corneal endothelial cells implanted with superparamagnetic microspheres migrated toward the magnetic field than human corneal endothelial cells not implanted with superparamagnetic microspheres. Cell migration did not affect cell viability or light transmission. Higher concentrations of 900-nm particles were associated with some loss of light transmission, the authors said.
“Further studies are planned to refine the technique and to examine in more detail the attachment and function of [human corneal endothelial cells] after direct cell seeding to Descemet’s membrane and bare stroma,” they said.
This interesting and innovative study evaluates a technique that may ultimately prove to be a major breakthrough in corneal transplant surgery. Think of the possibility of injecting some cells into the anterior chamber and using a magnet over the cornea to allow replacement of endothelial cells in pseudophakic bullous keratopathy or Fuchs’ dystrophy. With further work and evaluation, this may be a viable technique for use in clinical practice. Issues still to solve are the nature of the cells that will stay viable in the human for a long time, donor cell lines or growth of a patient-specific cell line. The other issue to solve is the best method of keeping the cells where they are intended to be — on the central posterior portion of the endothelium.
– David R. Hardten, MD
OSN Cornea/External
Disease Section Editor
There is a worldwide shortage of donor corneas suitable for transplantation, and although human corneal endothelial cells have been successfully cultured in a laboratory setting to expand the limited donor supply, methods are still being developed to successfully implant cultured cells in a human eye. In this study, superparamagnetic particles were incorporated into cultured cells, the cells were injected into a model eye, and a magnet was used to localize the cells to the posterior cornea.
This study is an important early step in the process of evaluating and optimizing this delivery technique. It will not have an immediate effect on clinical practice but may be a successful option in the long run.
– Marianne O. Price, PhD
Executive
Director, Cornea Research Foundation of America, Indianapolis