Glaucoma Can Be Treated With Stem Cell Secretions

Exosomes are stem cell secretions that seem to protect the retinal cells against glaucoma, reveals study.

Highlights:

Glaucoma is the second leading cause of blindness in the world.
Secretions from the stem cell called exosomes were found to promote survival of retinal cells.
Exosomes packed with proteins, lipids and gene-regulating RNA may help treat glaucoma.

Glaucoma is a condition that damages the optic nerve and often occurs due to the increased pressure in the eye. A recent study conducted by a research team from the National Eye Institute (NEI), part of the National Institutes of Health found stem cell secretions called exosomes may help protect the cells in the retina, the light-sensitive tissue in the back of the eye.

More than 60 million cases of glaucoma are noted worldwide which may increase to about 80 million in 2020. In India, the number of glaucoma cases is estimated to be 12 million.

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‘Stem cell secretions called exosomes may help treat glaucoma by protecting the retinal ganglion cells.’

According to the World Health Organization, glaucoma is the second leading cause of blindness in the world.

The study findings published in Stem Cells Translational Medicine, may produce new therapies for glaucoma.

Exosomes

Exosomes are stem cell secretions that are tiny-membrane enclosed packages which are formed inside the cells. The exosomes are usually packed with proteins, lipids and gene-regulating RNA. By fusing the target cell membrane, exosomes can be taken from one cell to another to make new proteins. They also provide signaling effect and facilitate cell-to-cell interactions.

Ben Mead, Ph.D., a post-doctoral fellow at NEI, found the role of stem cell exosomes on retinal ganglion cells (cells that form the optic nerve) which carry visual information from the eye to the brain. These cells when dead may result in vision loss in glaucoma and may cause optic neuropathies (optic nerve damage).

Stem cells can be used for developing new therapies as they can be converted into any type of cell in the body. Exosomes are a by-product of stem cells that may pose more advantages instead of transplanting the whole stem cells.

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Advantages of Exosomes

Mead, said, "Exosomes can be purified, stored and precisely dosed in ways that stem cells cannot."

Complications such as immune rejection and unwanted cell growth can be avoided as there is a lack of risk associated with transplanting live stem cells into the eye.

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Research Study on the Effect of Exosomes

The effect of exosomes was studied in a rat glaucoma model. Exosomes were fluorescently labeled and injected weekly into the vitreous humor(fluid present within the center of the eye).

Labeling the exosomes may help to track the delivery of exosome cargo into the retinal ganglion cells.

The study results obtained from electroretinography (eye test that measures the electrical activity of retinal cells) found exosome-treated rats to maintain function and have lost about one-third of their retinal ganglion cells followed by optic nerve injury when compared to a 90% loss in untreated rats.

Protective Effects of Exosomes

The research team found protective effects of exosomes are usually mediated by molecules which interfere with or silence gene expression, microRNA.

Stanislav Tomarev, Ph.D., a principal investigator at NEI also said that however further research is needed to understand more about the specific contents of the exosomes.

Tomarev, said, "We need to know which particular microRNA - there are more than 2000 different microRNA molecules - are delivered into the retinal ganglion cells and what proteins or signaling pathways are being targeted upon arrival.”

"We also need to attempt to target exosomes to specific sets of neurons and other cell types or groups of cells."

Combining exosomes with additional therapies may be the best approach to treat glaucoma.Treatment effects are based on how exosomes are administered to achieve a therapeutic effect.

Interesting Facts on Glaucoma

Older people are at a higher risk for glaucoma.
Approximately 1 out of 10,000 babies born in the United States are affected by glaucoma.
High eye pressure is only a risk factor for glaucoma.
Blindness due to glaucoma is 6 to 8 times more common among African Americans when compared to Causcasians.
There is no cure for glaucoma; vision loss can only be halted.
Early treatment can slow down the progression of the disease.

References:

Mead, B. and Tomarev, S. (2017), Bone Marrow-Derived Mesenchymal Stem Cells-Derived Exosomes Promote Survival of Retinal Ganglion Cells Through miRNA-Dependent Mechanisms. STEM CELLS Translational Medicine. doi:10.1002/sctm.12056 (link is external)
Glaucoma: An emerging peril - (http://www.ijcm.org.in/article.asp?issn=0970-0218;year=2013;volume=38;issue=3;spage=135;epage=137;aulast=Saxena)
Glaucoma Facts and Stats - (http://www.glaucoma.org/glaucoma/glaucoma-facts-and-stats.php)
Facts about Glaucoma - (http://www.visionaware.org/info/your-eye-condition/glaucoma/glaucoma-facts/125)
Glaucoma: Facts & Figures - (http://www.brightfocus.org/glaucoma/article/glaucoma-facts-figures)

Source-Medindia