Health Scan: Electric pulses zap fatty plaque in coronary arteries

Since heart disease remains the leading cause of death in the Western world, the Rubinsky technique offers a highly valuable tool.

March 29, 2009 00:40
Health Scan: Electric pulses zap fatty plaque in coronary arteries

human heart 88. (photo credit: )

A technique that cleans fatty plaque from the insides of coronary arteries that have undergone angioplasty but became reclogged has been developed by Hebrew University researchers. The team was headed by Prof. Boris Rubinsky, director of the center for bioengineering in the service of humanity and society at HU's Benin School of Computer Science and Engineering, who is also a professor at the University of California, at Berkeley's graduate school. Angioplasty is the "gold-standard" treatment for a heart attack, which is the result of abrupt interruption in blood supply to part of the beating heart, usually due to plaque-rupture in a hardened coronary artery. In angioplasty, a cardiologist dilates the blocked artery by inserting a balloon that is inflated at the point of blockage. This is usually followed by coronary stent implantation to hold the artery open. However, the procedure damages the arterial wall, so restenosis (reclogging) of the dilated artery remains a major problem in cardiology, as well as in other fields of clinical medicine. Since heart disease remains the leading cause of death in the Western world, the Rubinsky technique offers a highly valuable tool. It is based on the biophysical phenomenon of irreversible electroporation (IRE), which uses very short electric field pulses to destroy cells in seconds. It does not damage structures other than the cells themselves. Compared with other technologies for local destruction of cells and tissue, IRE is simple and does not require special training. In IRE, electrical fields are applied across targeted cells and penetrate cell membranes. This process leads to cell death, since the electrical fields cause permanent damage to the membranes and the consequent loss of cell stability. The electrical fields damage only the membranes, with no collateral damage. While the phenomenon of irreversible electroporation has been known for decades, Rubinsky and his team developed a new mode of application that affects only selected molecules. As a result, it has been rigorously considered only recently for various applications of tissue removal. In an article just published in the PLoS ONE, the HU team demonstrated that IRE can efficiently, safely and quickly destroy the cells responsible for restenosis in rats. In the study, IRE successfully destroyed almost all of those cells in less than 23 seconds, with no damage to any other structures. Clinical trials on humans are planned in the near future. IRE was recently used for the first time on human subjects in Melbourne for the treatment of prostate, liver and lung tumors. Clinical trials for follow-up through IRE of angioplasty treatments are planned for the near future. Prof. Jay Lavee, head of Sheba Medical Center's heart transplant unit, is cooperating with Rubinsky in development of the IRE technique for heart patients. SAVE YOUR INSIDES If you "have" to eat red (and especially factory-processed) meat despite the increased risk of colon cancer, minimizing the amount and combining vegetables and fruits with red meat in the same meal can reduce the carcinogenic effects, according to Dr. Niba Shapira, an adviser to the Israel Cancer Association and a leading Tel Aviv University clinical dietitian. While the number of people aged 50 to 74 who underwent a simple test to find occult blood in the stool increased to 336,000 last year, about 30% to 40% of those with a positive result did not go for a colonoscopy. As a result, colon cancer was diagnosed at a less-treatable stage in about 70 of them. March is National Colon Cancer Awareness Month marked by the Israel Cancer Association (ICA), which ran a publicity campaign to persuade those in the relevant age bracket to undergo an annual occult blood test. If the result is positive, your family doctor will refer you for an invasive colonoscopy. People with a higher risk of colon cancer - the second most common type of malignancy in Israel - because they have had colon cancer before or a family history of the disease, should go for a colonoscopy after being referred by their doctor. About 85,000 colonoscopy procedures were performed in 2008. Although the National Colon Cancer Detection Program that began four years ago in cooperation with the health funds has increased the number of occult blood tests for pre-cancerous lesions, over 3,181 new patients were added last year to the list of victims of colon cancer. Colon cancer is a preventible disease, and those who nevertheless develop pre-cancerous lesions can raise their survival rate to over 90 percent: Early detection of pre-cancerous polyps and their removal during colonoscopy can prevent them from becoming malignant and thus save lives. Some 400 Israelis were saved last year by early detection. But only 31 percent of people aged 50 to 74 who are not at higher risk went for occult blood tests, the ministry said. In addition to eating less (or no) red meat, the risk can also be reduced by eating more fruits and vegetables - especially green leafy ones and cruciferous vegetables such as broccoli, spinach and cauliflower. Thus, following a Mediterranean diet rich in fruits and vegetables is a good way to reduce colon cancer risk. Eating factory-processed red meat is even more dangerous than eating unprocessed meat. Eating poultry is much preferable to eating red meat, experts say. Poultry and fish have much less heme-type iron,which reduces the risk of colon cancer among non-vegetarians, according to research. Chlorophyll, which makes vegetables green, apparently helps neutralize the heme. Fruits and vegetables of a variety of colors contain carotenoids, which also help protect against colon cancer. A "significant breakthrough" in the fight against colon cancer is a study being conducted at Tel Aviv Sourasky Medical Center, where researchers have identified a protein found on the surface of the cell that is a biomarker for many cancerous processes, including those of the colon. Four hundred samples of tissue removed from patients with malignant colon cancer and pre-cancerous polyps were tested; the protein was expressed in about 90% of the tumors. The research, headed by Prof. Nadir Arber and Dr. Sarah Kraus, resulted in their development of a simple and innovative blood test based on expression of the protein in white blood cells. The test boasts 80% accuracy. Arber says he hopes to conclude the research within a year, and that if experiments continue to show such results, the test will become routine and help identify those patients who are not aware of the fact that they are at higher risk for colon cancer.

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