Source: Iowa State University
Date: August 2, 2007
New Treatment For Glaucoma Shows Promise In Laboratory, Say
Researchers
Science Daily — Iowa State University researchers have developed a
new technique that successfully treated rats for blindness caused by
glaucoma. Their experimental treatment will be used on canine
patients in the next year. If successful, it is expected to move to
human trials.
An estimated 3 million people in the U. S. are affected by glaucoma,
the second leading cause of blindness in the developed world and the
number one cause of vision loss among blacks. People with elevated
intraocular pressure are at greatest risk for developing glaucoma.
Iowa State researchers leading the six-year project are Dr. Sinisa
Grozdanic, a veterinary ophthalmologist and assistant professor of
veterinary clinical sciences; Donald Sakaguchi, neuroscientist and
associate professor of genetics, development and cell biology; and
Matt Harper, doctoral student in neuroscience. The team also included
researchers from the University of Iowa, Yale University, Tulane
University and the University of Miami. The work was presented at a
recent meeting of the Association for Research in Vision and
Ophthalmology Conference.
The researchers previously determined that animals with glaucoma
increase production of proteins with neuron-protective capabilities
(neurotrophins) in an attempt to shield against blindness. So, they
imitated that process in the laboratory, modifying bone marrow-
derived stem cells. Then they transplanted the cells into the eyes.
"Once we realized the nature of these self-protective mechanisms, we
just tried to mimic the same thing exactly," Grozdanic said. "We used
bone-derived stem cells from the patient, modified them to produce
the neurotrophin and injected these cells into glaucomatous eyes."
A sophisticated computerized analysis of noninvasive measurements of
optic nerve function and the retina's electrical activity showed
dramatic improvement in the rats' visual functions after the
procedure.
Four years earlier, the researchers had conducted experiments in
which biodegradable polymers coated with neuroprotective substances
were inserted into the eyes of rats. As the polymer degrades, the
neuroprotective substance is released into the eye. The approach
worked well, and the same procedure was successful in dogs with optic
nerve damage. However, because polymer-based drug delivery generally
lasts for only months and glaucoma destroys vision in humans over a
period of decades, the scientists shifted their strategy to a longer-
lasting approach. They genetically modified the bone marrow stem
cells for transplantation so the delivery of the neuroprotective
protein can be achieved for years.
"One of the really unique aspects of this approach is that we can
isolate these stem cells from the same individual being treated,"
Sakaguchi said. "It eliminates the ethical issues associated with
embryonic stem cells, and the immunological problems of graft
rejection."
Grozdanic said the "results were phenomenal." So, the Iowa State team
intends to use the technique on dogs as soon as possible.
"Dogs suffer many of the same diseases people do and there's a lot of
physiological similarity in their eyes and ours," Grozdanic said.
"Four years ago, I was very skeptical that this would work," he
said. "Now I see positive results. Hopefully in a few years, we'll be
able to say it's working in humans."
The cell biology work and the genetic modification were conducted by
Sakaguchi and Harper, while Grozdanic developed techniques for
evaluating the molecular changes in the animals. Researchers at the
University of Miami provided genetic material for the modification
while collaborators at Tulane assisted with culturing the bone marrow
stem cells. A biodegradable polymer engineered with neuroprotective
substances used in preliminary testing was developed by Erin Lavik at
Yale University. Three faculty from the University of Iowa's
Department of Ophthalmology and Visual Sciences - Dr. Randy Kardon,
Dr. Young Kwon and Dr. Markus Kuehn - helped develop models of
elevated eye pressure and assessing visual function. They also
compared data from tissue from the rats and dogs to data from human
donor tissue to help the team better understand molecular changes
caused by glaucoma.
Note: This story has been adapted from a news release issued by Iowa
State University.
http://www.scienced
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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