EU-funded study raises hopes for aneurysm sufferers
It may be possible to treat aortic aneurisms with asthma drugs, according to new EU-funded research. The discovery, outlined in the Proceedings of the National Academy of Sciences (PNAS) journal, could help save lives and cut the need for often risky surgery. The body's largest blood vessel, the aorta, transports blood from the heart to the rest of the body. This immense artery descends through the chest cavity and into the abdomen before splitting into two arteries (one for each leg) around the pelvis. Sometimes a section of the aorta weakens and balloons outwards under the pressure of the blood being pumped through it; this is known as an aneurysm. Mostly this occurs in the abdomen; a person is diagnosed with an abdominal aortic aneurysm if the diameter of the aorta at a given point exceeds 30 millimetres (mm) (the normal diameter of the aorta in the abdomen being around 20 mm). If the aneurysm becomes too enlarged, it can rupture, triggering massive internal bleeding and, all too often, death. Scientists have discovered that aneurysms arise when certain enzymes slowly break down the tissues that make up the walls of the aorta, causing it to become weaker. In this latest study, researchers from Finland and Sweden found that the walls of aneurysms contain high levels of enzymes that are able to form substances called cysteinyl-leukotrienes. 'We've also found that cysteinyl-leukotrienes can stimulate the release of protein-digesting enzymes called metalloproteases, which can contribute to the weakening of the aortic wall and the development of an aneurysm,' commented Professor Jesper Haeggström of Sweden's Karolinska Institutet, who led the study. Cysteinyl-leukotrienes are known to medicine; they are also responsible for the swelling of the airways associated with asthma. Furthermore, asthma patients are routinely treated with drugs designed to block the action of cysteinyl-leukotrienes. Experiments revealed that these drugs are able to block the cysteinyl-leukotrienes and prevent the release of metalloproteases. The findings suggest that asthma drugs could help treat aneurysms and reduce the risk of rupture. According to the researchers, setting up a clinical trial to test this theory should be straightforward. 'These asthma drugs are both efficacious and safe, and we should soon be able to test any positive effect they might have on aortic aneurysm,' said Professor Haeggström. The incidence of aneurysm increases with age; some 6 in 100 men and 2 in 100 women over the age of 65 are affected. Atherosclerosis ('furring up' of the arteries with fatty deposits), high blood pressure and smoking are also risk factors for the condition. What makes aneurysms so dangerous is their tendency to rupture if they become too large. If the aorta ruptures, the person suffers massive internal bleeding. Emergency surgery in these cases can save lives; nevertheless, 8 out of 10 patients who suffer a rupture die. The problem is that many people do not know they have an aneurysm; over two thirds of patients diagnosed with the condition reported no symptoms. Certain scans, such as ultrasound, can detect aneurysms. If the aneurysm is small, the doctor may advise a 'wait and see' approach, scheduling regular exams to track the growth of the aneurysm. If the aneurysm is over 50 mm across, the risk of rupture is much higher; in these cases, an operation may be carried out to repair the artery. As this surgery carries risks of its own, it is only advised in cases where the risk of rupture is higher than the risk of surgery. EU support for the work came from three projects: EICOSANOX ('Eicosanoids and nitric oxide: mediators of cardiovascular, cerebral & neoplastic diseases'), ATHEROREMO ('European collaborative project on inflammation and vascular wall remodelling in atherosclerosis') and FAD ('Fighting aneurysmal diseases'). EICOSANOX received EUR 10.7 million under the 'Life sciences, genomics and biotechnology for health' Thematic area of the Sixth Framework Programme (FP6). ATHEROREMO and FAD received EUR 11.7 million and EUR 11 million respectively under the Health Theme of the Seventh Framework Programme (FP7).
Countries
Finland, Sweden