HELP EXPLAIN CHEMO BRAIN THROUGH SNAIL RESEARCH
It is estimated that as many as half of patients taking cancer drugs
experience a decrease in mental sharpness. While there have been many theories,
what causes "chemo brain" has eluded scientists.
In an effort to solve
this mystery, neuroscientists at The University of Texas Health Science Center
at Houston (UTHealth) conducted an experiment in an animal memory model and
their results point to a possible explanation. Findings appeared in The
Journal of Neuroscience.
In the study involving
a sea snail that shares many of the same memory mechanisms as humans and a drug
used to treat a variety of cancers, the scientists identified memory mechanisms
blocked by the drug. Then, they were able to counteract or unblock the mechanisms
by administering another agent.
"Our research has
implications in the care of people given to cognitive deficits following drug
treatment for cancer," said John H. "Jack" Byrne, Ph.D., senior
author, holder of the June and Virgil Waggoner Chair and chairman of the
Department of Neurobiology and Anatomy at the UTHealth Medical School.
"There is no satisfactory treatment at this time."
While much work
remains, Byrne, who runs the university's Neuroscience Research Center, said
understanding how these drugs impact the brain is an important first step in
alleviating this condition characterized by forgetfulness, trouble
concentrating and difficulty multitasking.
Byrne's laboratory is
known for its use of a large snail called Aplysia californica to further the
understanding of the biochemical signaling among nerve cells (neurons). The
snails have large neurons that relay information much like those in humans.
When Byrne's team
compared cell cultures taken from normal snails to those administered a dose of
a cancer drug called doxorubicin, the investigators pinpointed a neuronal
pathway that was no longer passing along information properly.
With the aid of an
experimental drug, the scientists were able to reopen the pathway.
Unfortunately, this drug would not be appropriate for humans, Byrne said.
"We want to identify other drugs that can rescue these memory
mechanisms," he added.
The scientists
confirmed their findings in tests on the nerve cells of rats.
"The big picture
is to determine if this cancer drug acts in the same way in humans," Byrne
said.
According the American
Cancer Society, some of the distressing mental changes cancer patients
experience may last a short time or go on for years.
Byrne's UTHealth
research team includes co-lead authors Rong-Yu Liu, Ph.D., and Yili Zhang,
Ph.D., as well as Brittany Coughlin and Leonard J. Cleary, Ph.D. All are
affiliated with the W.M. Keck Center for the Neurobiology of Learning and
Memory.
Byrne and Cleary also
are on the faculty of The University of Texas Graduate School of Biomedical
Sciences at Houston. Coughlin is a student at the school, which is jointly
operated by UTHealth and The University of Texas MD Anderson Cancer Center.
The study titled
"Doxorubicin Attenuates Serotonin-Induced Long-Term Synaptic Facilitation
by Phosphorylation of p38 Mitogen-Activated Protein Kinase" received
support from National Institutes of Health grant (NS019895) and the Zilkha
Family Discovery Fellowship.
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