- 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
- Exosomes packed
with proteins, lipids and gene-regulating RNA may help treat 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
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.
‘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
The study findings
published in Stem Cells Translational Medicine
, may produce new
therapies for glaucoma.
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.
Advantages of Exosomes
"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.
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
Labeling the exosomes
may help to track the delivery of exosome cargo into the retinal ganglion
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.
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
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
- There is no cure
for glaucoma; vision loss can only be halted.
- Early treatment
can slow down the progression of the disease.
- 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)