Amyloidosis Gets Illuminated By X-Rays


Any Dr. House fans out there?  I am totally raising my hand.

If you watch the medical shows, you might hear Dr. House or Foreman say something about Amyloidosis, Lupus, or Sarcoidosis.  Someone inevitably says “it’s not lupus,” and House makes a smarmy comment about always being right.  That first condition, Amyloidosis, just got some press that I thought was pretty interesting.

Amyloidosis is  a weird unexpected buildup of the amyloid beta protein in organs of the body; it causes all kinds of really bad conditions, some of which are not well understood.  Amyloid beta protein plaque buildup is known for being present in Alzheimer Disease patients, and can affect the heart, nervous system, GI tract, liver, kidneys, and is a very nasty little monkey.  The protein builds up and just causes the organ to fail.  Unfortunately there is no cure yet, but medicines improve someone’s quality of life, from what I have been reading.

The search for a cure is ongoing, and after two paragraphs of rambling I am finally going to get to the story!  Scientists have had some success with using very high powered x-ray beams to image the amyloid beta plaques; this is a very difficult task for any imaging technology because of the amyloid size – around one millionth of a meter.  In a press release from Brookhaven National Lab, where the big Synchrotron light source lives and where the testing took place, the process is discussed:

“These plaques are very difficult to see, no matter how you try to image them,” said Dean Connor, a former postdoctoral researcher at Brookhaven Lab now working for the University of North Carolina. “Certain methods can visualize the plaque load, or overall number of plaques, which plays a role in clinical assessment and analysis of drug efficacy. But these methods cannot provide the resolution needed to show us the properties of individual Aß plaques.”

A technique developed at Brookhaven, called diffraction-enhanced imaging (DEI), might provide the extra imaging power researchers crave. DEI, which makes use of extremely bright beams of x-rays available at synchrotron sources such as Brookhaven’s National Synchrotron Light Source, is used to visualize not only bone, but also soft tissue in a way that is not possible using standard x-rays. In contrast to conventional sources, synchrotron x-ray beams are thousands of times more intense and extremely concentrated into a narrow beam. The result is typically a lower x-ray dose with a higher image quality.

Also, on how the beam works:

To make a diffraction-enhanced image, x-rays from the synchrotron are first tuned to one wavelength before being beamed at an anatomical structure or slide. As the monochromatic (single wavelength) beam passes through the tissue, the x-rays scatter and refract, or bend, at different angles depending on the characteristics of the tissue. The subtle scattering and refraction are detected by what is called an analyzer crystal, which diffracts, or changes the intensity, of the x-rays by different amounts according to their scattering angles.

The diffracted beam is passed onto a radiographic plate or digital recorder, which documents the differences in intensity to show the interior structural details.

Finding out how to see this amyloid plaque buildup is a very useful tool in tracking Alzheimer’s in patients because if we know what to look for, we can possibly see into the future a little in testing and make predictions that could save lives.  Testing has been done on mice, but the procedure still delivers too high a radiation dose for human testing.  Part of the process towards using the technique clinically is to lower that dosage, obviously.

amyloid plaque buildup

Thanks, BNL and Medgadget!

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