Engineers have found a way to pinpoint and identify the tiny iron
oxide particles associated with Alzheimer's and other
neurodegenerative diseases in the brain.

The technique is likely to accelerate research on the cause of the
diseases and could lead to the first diagnostic procedure for
Alzheimer's in patients while they are alive.

"We're the first to be able to tell you both the location of the
particles and what kind of particles they are," said Mark Davidson,
a University of Florida engineer in UF's materials science and
engineering department.

Davidson and collaborators at UF and Keele University in England
have published at least four articles on their research in scholarly
journals. Their latest article has been accepted for publication in
the Journal of Alzheimer's Disease.

Alzheimer's, Huntington's and Parkinson's diseases affect millions
of Americans and cost billions of dollars annually for patient
treatment and care. Alzheimer's is the most common of the three,
afflicting 4.5 million Americans, with numbers projected to grow as
the baby boomers age, according to the Alzheimer's Association. The
diseases share some potential symptoms, including physical
impairments and dementia.

Although Huntington's is caused by a genetic disorder, little is
understood about precisely how Huntington's, Alzheimer's and
Parkinson's wreak havoc in the brain. However, medical researchers
have long known that afflicted regions tend to contain unusually
high concentrations of iron oxide and other iron-containing
particles.

This observation is complicated by the fact that healthy brains also
contain iron â€" indeed, iron is essential for normal brain
function.

Traditional methods for studying the properties of "bad iron" tied
to neurodegenerative diseases involve staining tissue sections to
reveal the location of the iron, or extracting the particles. But
these approaches reveal neither the specific iron compounds present
nor the relationship of those compounds to specific structures
within the tissue.

Electron microscopes don't work either because their tight
resolution makes it impossible to search enough area to find the
iron.

"It would take you a career to look at one piece of tissue,"
Davidson said.

To solve the problem, Davidson and Chris Batich, a professor of
materials science and engineering, along with Albina Mikhaylova, Jon
Dobson and Joanna Collingwood of Keele University, turned to an
unlikely facility: the synchrotron at the U.S. Department of
Energy's Argonne National Laboratory near Chicago.

The synchrotron is an electron accelerator that produces the most
powerful X-rays in the nation. Also known as the Advanced Photon
Source, it is usually used for basic science experiments in high-
energy physics. But the UF researchers crafted a system of mirrors
and lenses that taps one of the cyclotron's 35 "beam lines," or X-
ray sources, for the new purpose of analyzing brain tissue.

The results are impressive. Whereas an electron microscope can
examine tissue one micron, or one thousandth of a centimeter, the
new device can look at tissue two or three hundred microns in size.
If it locates a particle, it then uses traditional spectroscopic
methods to zoom in and determine what sort of iron the particle
happens to be.

"It's the equivalent of being up in an airplane, looking at the city
of Tampa, and telling you whether there is a penny there or not,"
Davidson said. "And then once we zoom in, we can tell you what kind
of penny it is."

So little is understood about the role of iron in neurodegenerative
diseases today that it's not even clear whether the iron is a
symptom or a cause, Batich said. The UF technique may help by giving
researchers a clearer view of the problem.

"The basic idea is, if you understand the mechanism, you can
understand ways to try to treat the disease," he said.

But the UF technique could also have clinical value. Davidson said
that the group is planning to do experiments that could one day lead
to using magnetic resonance imaging, or MRI, to highlight damaging
iron in patients' brains.

"If we can adjust the MRI to look for specific iron compounds
related to Alzheimer's we may be able to provide a technique for
early diagnosis before clinical symptoms appear. The major advantage
of this is that most treatments currently in development rely on
early detection to slow or halt progression of the disease, as they
cannot reverse it," he said.
Article Date: 27 Feb 2006