CARS imaging shows calcium ions may have role in multiple sclerosis
11 July 2007 Researchers at Purdue University have
discovered that calcium ions could play a crucial role in multiple sclerosis
by activating enzymes that degrade the fatty sheath that insulates nerve
fibres. The researchers employed an imaging technique called coherent
anti-Stokes Raman scattering, or CARS, that uses interfering laser beams to
vibrate and identify selected molecules. In this study they showed how the
myelin sheath is degraded by a molecule called lysophosphatidylcholine (LPC). 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 fatty molecules in the myelin
called lipids. Cytosolic
phospholipase A2 cuts off one of the two tails of these lipid molecules and
turns them into LPC, amplifying the effect and further
degrading the myelin. 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. LPC, does not cause multiple sclerosis, but it is used extensively in
laboratory research to study the deterioration of myelin, which insulates
nerve fibres and enables them to properly conduct impulses.
"Although multiple sclerosis has been studied for many years, nobody knows
exactly how the disease initially begins. The pathway is not
clear. It is possible that the same pathway causes myelin
degradation in people suffering from multiple sclerosis and spinal cord
injuries," Cheng said. The research
findings were published in the Journal
of Neuroscience Research in June.
"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 Riyi 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." To top
|
