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8-Humans: New gene therapy technique announced



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TITLE:  Gene therapy breakthrough
SOURCE: British Broadcasting Corporation
        http://news.bbc.co.uk/1/hi/health/2780325.stm
DATE:   Feb 24, 2003

------------------ archive: http://www.gene.ch/genet.html ------------------


Gene therapy breakthrough
The technique uses tiny bubbles

Scientists have developed a more effective way to carry out gene therapy
without the risks of current methods. The modification of genes offers
the potential to treat or cure many diseases. But the use of viruses to
deliver the modified genes to the target tissue is not always safe, and
other methods do not seem to work well.

The latest technique, developed by scientists at Imperial College London
and the Medical Research Council in the UK, appears to be effective - and
does not require the use of viruses. It works by combining the use of
microbubbles and ultrasound. So far it has been tested on skeletal muscle
in mice, but it is hoped it may eventually be used to treat muscular
dystrophy in children.


Tiny bubbles

We need to build on the research to improve the technique and assess the
possible impact it could have on diseases such as muscular dystrophy,
cancer, and diseases of the heart Dr Martin Blomley Microbubbles are
already in use to improve patient ultrasound scans in the heart, liver
and many other areas and are known to be both safe and effective.

They are tiny gas bubbles measuring about three microns, and are usually
injected intravenously to boost ultrasound signals. But there is also
evidence that when ultrasound is applied to microbubbles, the
microbubbles pop and this can cause small perforations in the target
cells which allow the DNA to enter. This enabled the researchers to
develop a "point and shoot" approach to gene therapy. They mixed a type
of microbubble already in use by doctors for scanning patients with
modified DNA and injected it into the skeletal muscle cells of mice of
different ages.

The target cells were then subjected to ultrasound to disrupt them, and
make them more likely to take up the modified DNA. The technique proved
to be 10 times more effective than more conventional methods. Even the
use of microbubbles alone without ultrasound proved to be more effective,
particularly in younger mice. In addition, the amount of inflammation and
damage associated with the injection was reduced when microbubbles were used.


Great promise

Currently, most gene therapy uses viruses to transport the modified genes
to their intended location. However, this can lead to infection of non-
target tissues, and can stimulate dangerous immune responses.

Researcher Dr Martin Blomley said: "What we've found here seems a
promising lead into a new, safe and effective way of delivering genes
into target cells."

"Gene therapy holds great promise in future for curing and ultimately
preventing serious diseases but is still in its infancy as a clinical tool."

"This promising study suggests that there may be a less invasive and more
efficient, safe and accurate technique for targeting tissue, than those
currently in use."

"Now we've found a good delivery system, we need to build on the research
to improve the technique and assess the possible impact it could have on
diseases such as muscular dystrophy, cancer, and diseases of the heart."