Fantastic voyage probe detects clots

In what appears to be straight out of a science-fiction movie, scientists have developed what they claim is a miniature submarine which can pass through a person's bloodstream to spot dangerous clots and deposits.

In what appears to be straight out of a science-fiction movie, scientists have developed what they claim is a miniature submarine which can pass through a person's bloodstream to spot dangerous clots and deposits.

Existing probes are essentially cameras that can travel inside arteries. Doctors must spot deposits and judge whether they are likely to come loose and block an artery.

Now, the submarine, called the new probe, developed at the Massachusetts General Hospital in Boston, also detects molecules that mark out the most harmful clots and fatty plaques, the New Scientist reported.

To test the probe, the scientists first fed rabbits a diet that generated arterial deposits. They then injected them with a fluorescent chemical that tags the danger-sign molecules. The probe carries a detector for the fluorescent light, which revealed bright areas on artery walls where the tags had found their targets.

The scientists were able to detect fibrin -- a protein that causes clots to form, and cathepsin B, an enzyme found in the most dangerous plaques. In principle, any molecule could be detected, including molecular signatures of cancer, say the scientists. And just like on the submarine, lasers to zap suspicious lesions could be added.

"Although it would require further development, it is possible to combine therapy into the (probe) to combat dangerous plaques," Guillermo Tearney, the lead scientist, said.

Detecting fibrin could be especially valuable for people who have had arterial blockages opened through the surgical fitting of stents.

Often, these rapidly become reblocked, and the first sign that this is happening is the deposition of fibrin on the stent.

Existing probes cannot distinguish fibrin from healthy deposits such as the cells that line the stent. The fluorescence tests can, so doctors can give clot-busting drugs before blockages can form.

The scientists, whose findings have been published in the latest edition of the Nature Medicine journal, now intends to test the device in people undergoing surgery for coronary artery disease.