Limbal stem cells will help restore vision

Scientists have learned how to use stem cells to grow cornea

Anna Govorova, Infox.ruResearchers from several Boston institutes have found a new way to restore the cornea of the eye.

They discovered the molecule ABCB5, which indicates limbal stem cells that are able to regenerate and repair corneal tissues themselves. Scientists have even managed to transplant these cells to mice whose cornea has fully recovered. According to the authors, this method will someday help people who have lost their eyesight as a result of injuries and burns.

The cornea is a transparent shell covering the front of the eye. At the same time, it works as an optical system and is the strongest refractive lens of the eye. Together with the lens, the cornea focuses light on the inner shell – the retina. Then the image is transmitted along the optic nerve to the brain, where the visual image is formed.

The transparency of the cornea is provided by a layer of endothelial cells.

Limbal stem cells, as the authors explain, are extremely important for our vision – they support, restore and renew corneal cells every few weeks. Without these cells, the cornea becomes cloudy and vision is impaired. The lack of these cells due to illness or injury is the main cause of vision loss.

But it turned out to be very difficult to detect these cells.

"Limbal stem cells are extremely rare, and the success of transplantation largely depends on these rare cells. Our study helps to detect these cells, and this will greatly simplify the process of restoring the cornea," says one of the authors, Dr. Bruce Ksander from the Massachusetts Institute for the Study of Vision and Hearing.

The ABCB5 molecule was originally found in human skin and intestines – these studies were conducted in the Department of Genetics at Boston Children's Hospital. In the new work, the authors found this molecule in the limbal stem cells of the cornea.

The scientists also found out that in mice that did not have the gene encoding ABCB5, the population of limbal stem cells disappeared, and after damage to the cornea did not heal well.

"The ABCB5 molecule allows limbal stem cells to survive by protecting them from apoptosis – programmed cell death," explains Markus Frank.

"In a mouse model, we were able to understand for the first time the role of this molecule in the development of the cornea. It is possible that this molecule plays an important role for the work of other stem cells. Moreover, one laboratory would not be able to do such work. The efforts of geneticists and transplant specialists were necessary, many technical subtleties had to be taken into account in order to do this work," adds Natasha Frank, one of the authors of the study.

The results of the study by American scientists are published in the latest issue of the journal Nature: Ksander et al., ABCB5 is a limbal stem cell gene required for corneal development and repair.

The press release of Researchers Regrow Human Corneas: First Known Tissue Grown from a Human Stem Cell can be read on the website of the Massachusetts Eye and Ear Clinic. Recall that two years ago, Japanese researchers showed that the suppression of the activity of the enzyme Rho-associated kinase makes it possible to effectively use conventional, non-stem cells of the corneal endothelium – VM for transplantation.

Portal "Eternal youth" http://vechnayamolodost.ru03.07.2014