PeopleWithMS - NewsWire
Crucial Role In Multiple Sclerosis Discovered
Researchers have discovered that calcium ions could play a crucial role
in multiple sclerosis by activating enzymes that degrade the fatty
sheath that insulates nerve fibers.
Learning exactly how the myelin sheath is degraded might
enable scientists to determine how to halt disease progress and reverse
damage by growing new myelin, said Ji-Xin Cheng, an assistant professor
in Purdue University's Weldon School of Biomedical Engineering and
Department of Chemistry.
"Although multiple sclerosis has been studied for many years,
nobody knows exactly how the disease initially begins," he said. "The
pathway is not clear."
Purdue researchers used an imaging technique called coherent
anti-Stokes Raman scattering, or CARS, to study how the myelin sheath
is degraded by a molecule called lysophosphatidylcholine, known as LPC.
The LPC does not cause multiple sclerosis, but it is used extensively
in laboratory research to study the deterioration of myelin, which
insulates nerve fibers and enables them to properly conduct impulses in
the spinal cord, brain and peripheral nervous system throughout the
body.
The findings suggest that LPC causes sheath degradation by
allowing an influx of calcium ions into the myelin. The increased
concentration of calcium ions then activates two enzymes - calpain and
cytosolic phospholipase A2 - which break down proteins and molecules in
the myelin called lipids.
"It is possible that the same pathway causes myelin
degradation in people suffering from multiple sclerosis and spinal cord
injuries," Cheng said.
The research demonstrates that CARS microscopy is a valuable
research tool and could become a future clinical method to diagnose
multiple sclerosis and detect damage to the spinal cord from accident
trauma, which also causes the myelin to degrade, he said.
Research findings are detailed in a paper appearing online
this month in the Journal of Neuroscience Research. The paper was
authored by biomedical engineering doctoral student Yan Fu and
postdoctoral research associate Haifeng Wang; Terry B. Huff, a graduate
teaching assistant in the Department of Chemistry; Riyi Shi, an
associate professor of basic medical sciences in Purdue's School of
Veterinary Medicine and an associate professor of biomedical
engineering; and Cheng.
"The findings of this study will help us to identify key steps
in the progression of the demyelination, which is a hallmark of
multiple sclerosis," said Shi, a researcher at Purdue's Institute for
Applied Neurology and Center for Paralysis Research. "This information
will also facilitate the design of pharmaceutical interventions that
slow down or even reverse the development of the debilitating disease."
The researchers used CARS to study and take images of healthy
and diseased myelin. The researchers showed that an enzyme called
cytosolic phospholipase A2 contributes to myelin degradation by
snipping off one of the two tails that make up lipid molecules
contained in the myelin. Cutting off one of the tails turns the lipid
molecules into LPC, amplifying the effect and further degrading the
myelin.
The research was carried out in spinal cord tissues extracted from animals and in the sciatic nerves of living mice.
Findings were confirmed by comparing CARS results with electron
microscope images and measurements of electrical impulses in spinal
cord tissue that distinguish between normal and diseased myelin.
CARS imaging takes advantage of the fact that molecules
vibrate at specific frequencies. In a CARS microscope, two laser beams
are overlapped to produce a single beam having a new frequency
representing the difference between the original two beams. This new
frequency then drives specific molecules to vibrate together "in
phase," amplifying the signals from those molecules.
|
|
|
