An international group of scientists has presented a new technology for creating artificial heart valves for implantation. The authors of the development believe that the approach they proposed will allow avoiding re-transplantation after the wear of the primary implant. The study is published in Nature Medicine.
An international study led by Dr. Vered Padler-Karavani from Tel Aviv University showed that the destruction of implantable heart valve bioprostheses is due to tissue calcification caused by an immune response to foreign animal sugars. Scientists have proposed using genetic engineering to modify animals from which tissues are taken for transplantation.
Valvular heart disease is the most common disease of the cardiovascular system. Heart defects affect about 2% of the population in developed countries. Almost half of these diseases are aortic valve stenoses. Therapeutic valve replacement is the second most popular heart surgery after coronary artery bypass grafting.
The researchers explain that currently, patients can be implanted with either mechanical heart valves or biological prosthetic heart valves made from bovine, porcine or equine tissue. Mechanical implants last a long time, but require daily anticoagulants. Biological prostheses allow patients to live normal lives, but typically break down in ten years and need to be replaced.
“Because bioprosthetic heart valves are made from animal tissue, we hypothesized that they contain sugars foreign to humans (Neu5Gc and alpha-Gal) that are attacked by the patient’s immune system,” says Padler-Karavani. “Our studies confirmed this hypothesis.”
The study involved about 1,700 patients who received 5,000 blood samples at various times after implantation. Scientists note that all patients developed an immune response against foreign sugars.
To prevent an immune response and calcification of the implant, scientists have proposed the use of genetic engineering. Researchers have created genetically modified pigs that do not produce sugars foreign to humans. Experiments carried out in an artificial environment have shown that the tissue obtained from such pigs is significantly less calcified even in the presence of antibodies against these sugars.
“This study marks a technological breakthrough in the field of artificial heart valves and provides a deep understanding of the mechanisms leading to structural valve wear,” says Padler-Karavani. “Our results could lead to a significant improvement in the quality of life of many patients with cardiovascular problems.”