- European scientists have developed a new technique to detect
attogram quantities of iron in living cells. - providing further
evidence of the role the metal plays in Parkinson's disease.
Iron is thought to form bulky chelate complexes with the
neurotransmitter dopamine in diseased cells, preventing it from
being stored or transported properly. But to date this has only been
confirmed in the test tube because conventional imaging techniques
are not powerful enough to pick up the tiny traces of iron.

Now, a team led Richard Ortega at the University of Bordeaux,
France, has used powerful X-ray radiation from a synchrotron to
track iron in cells cultured from rats.

By using a highly focused beam of X-rays with a wavelength of 88nm,
the team excited the iron in the cell and recorded the radiation
released by the metal -detecting amounts as small as one attogram
(10-18g). They then mapped dopamine in the same cell using
ultraviolet fluorescence spectroscopy and superimposed the images
from the two techniques.

When they compared the images they got from normal cells and cells
treated to mimic the onset of Parkinson's disease, they found iron
accumulating inside the dopamine storing vesicles of the cell.

The new X-ray setup opens up many possibilities for similar
research, Ortega told Chemistry World. 'This research is in an early
stage [but] the work provides a new way of thinking about treatment
of Parkinson's disease.'

Olivier Hignette of the European Synchrotron Radiation Facility
(ESRF), who helped develop the equipment used in the research, said
stronger more energetic X-rays could allow many more metals in cells
to be probed.

'We are not yet at the limit of this technology,' he said. 'Upon
improvement of the apparatus, 40 or even 30nm radiation with similar
photon fluxes may be achieved.'

Commenting on the work, David Dexter of Imperial College London, who
works on the role of iron in neurodegenerative diseases, said, 'This
does strengthen the idea of the contribution of iron to
neurodegenerative diseases. It certainly adds a new dimension to the
whole problem.'

Jonathan Edwards
02 October 2007(RSC)