Artificial heart valves are devices implanted in the heart when the native valves malfunctions. There are two main types of artificial heart valves: the mechanical and the biological. Mechanical heart valves use mainly metallic materials and are more durable that biological valves. However, mechanical heart valves require lifelong treatment with anticoagulants (blood thinners), requiring monthly blood tests to monitor anticoagulation. In spite of this, these individuals have a significantly higher risk of bleeding than the rest of the population. Biological heart valves use organic tissues and do not require the use of anticoagulant drugs due to less blood cell damage and, consequently, less clot formation. However, they have a limited lifespan. The biological tissues from pig heart valves, or bovine and equine pericardium (a cardiac tissue) endure on average 15 years, though it may be less in younger persons.
Implantation of a biological valve implies in most of cases the exposure to tissues from another species (pig, cow, horse). Consequently, there is a predisposition of the human body’s to reject these tissues. Thus, once the tissue is removed from the animal, it is chemically treated to preserve the tissue and prevent immunologic reactions once it is placed in a patient. This approach is very successful for many years. However, it cannot be ruled out than ongoing slow acting immunologic reactions damage the biological heart valve and end causing a valve failure. The TRANSLINK project aims to identify these immunologic reactions and offer remedies for its prevention or treatment.
The TRANSLINK Consortium includes specialists in Cardiothoracic Surgery, Cardiology, Immunology, Veterinary, Chemistry and Drug Design. The main goal of the project is to assess the potential role in the damage of biological heart valves of several antibodies that all the individuals hold. These antibodies are similar to those responsible for the blood group incompatibility, though they react to tissues from other species. To avoid the harm of these antibodies two strategies are evaluated. One includes the use as source of tissue pigs genetically prepared to be less reactive to the human immunologic system. The other approach is the design and production of drugs to selectively deplete those antibodies that cause the injury to the biological heart valves. The success of TRANSLINK may lead to a prolongation of the lifespan of biological heart valves, making them similar to mechanical valves, and their use in younger persons.