Biomedical engineering researchers at the Technion-Israel Institute of Technology have suggested a revolutionary technique to prevent restenosis (reclogging) of coronary arteries after supportive metal-mesh stents have been inserted by angioplasty. Restenosis affects as many as 40 percent of patients who have undergone the procedure. The technique, whose award of a US patent was announced on Monday, can also be applied to "any drug" that works best in a specific site of the body, including anti-cancer medications, the researchers say. Angioplasty - a minimally invasive cardiological intervention in which a tiny deflated balloon is inserted into clogged arteries in the heart and inflated to open blockages and position a stent inside the weak arterial wall to keep it open - results in blockages in more than a third of patients. The cause is not new fatty plaques in the same spot of the arteries, as had been thought, but the growth of tissue in the endothelium of the vessel. Doctors regards this as a "tumor" that has to be treated with medication to prevent uncontrolled growth of the tissue. But anti-tumor drugs cannot be taken systemically to affect the whole body, because the growth is local. Stent manufacturers insert the drug into the stent, and this inhibiting chemical is supposed to be released slowly over six months, when the risk of restenosis is greatest. But the problem is that control of this release process is not exact enough for it to prevent regrowth of tissue in all cases. In the new technique - developed by Prof. Noah Lotan, Dr. Sarit Sivan and Prof. Uri Dinnar - the patient swallows a completely neutral "pre-drug" amino acid that causes no side effects and can be taken as long as needed. This amino acid activates a specific enzyme in a special stent, serving as a "factory" for the anti-clogging drug as long as the amino acid is consumed. The amino acid is a natural component of every protein and is contained in soya and milk products, among others, thus it can be safely consumed. The patient stops taking the amino acid six months after angioplasty, when there is no longer a risk of uncontrolled tissue growth inside the artery. The most exciting aspect of the process, on which the Technion researchers have been working for two and a half years, is that it can be applied to "every known drug today and be useful for medications that are best administered locally, in one part of the body." One example is cancer drugs, Lotan told The Jerusalem Post Monday. "We have developed a technological platform with wide applications, as a pre-medication can be swallowed and a coordinated enzyme can be used for each application," he said. Lotan said the patented process was so new that no company had yet signed an agreement to pursue it. "It would take several years until it became available for patients, and no clinical trials have been launched," he said. "We are looking for commercial interests and would, of course, like it to be an Israeli company if possible."