The month of February is a big month for hearts. Between Valentine’s Day and American Heart Month, you cannot escape heart-shaped decorations and reminders to exercise daily. And while many of us are fortunate that our heart health can be maintained through diet and exercise, there are some cases where that is not enough. Individuals with certain congenital heart defects, weakened heart muscles, or other types of heart disease may need a totally new heart. In the United States, about 2,300 heart transplants occur each year with over 70% of those patients surviving for five years afterwards. This high survival rate is in stark contrast to the early days of heart transplants in the late 1960s and 1970s, and it is largely due to advances not in heart physiology, but the immune system.
Our immune systems are exceptionally good at identifying foreign invaders and attacking them. In the cases of bacterial or viral infections, the immune system’s voracious assault on foreigners keeps us healthy. However, in the case of a heart transplant, where foreign tissue is introduced to the body to save the patient’s life, such voracity is detrimental to survival. A distressing catch-22 emerged as early heart transplants were performed – doctors gave patients powerful immunosuppressants to prevent rejection of the heart, but these drugs left the immune system so weakened that it could not fight off post-surgical infections. Eventually, a breakthrough came from an unexpected place – a Norwegian soil fungus.
While on vacation in Norway, a scientist collected a soil sample that would change the fate of organ transplants forever. The soil sample was taken to Sandoz Pharmaceutical Ltd. where Jean-Francois Borel worked diligently with a team of scientists to characterize an interesting compound found in the Norwegian soil: cyclosporine, which was made from a fungus.
Sandoz Pharmaceutical was interested in developing new antibiotics, but, cyclosporine did not prove to be an effective antibiotic. Luckily for future recipients of heart transplants, cyclosporine did show promise as an immunosuppressant. Cyclosporine specifically inhibited white blood cells and T cells instead of killing them, thus preventing organ rejection while still allowing the immune system to fight off infections. Dr. Borel and his team faced several setbacks while studying cyclosporine, including pressure from Sandoz to discontinue the studies. However, they persisted until 1983 when the Food and Drug Administration approved cyclosporine as an immunosuppressant for all organ transplants. Many healthy hearts are beating today due to cyclosporine, and a heartfelt thanks goes out to the countless individuals who worked so hard to make these survival stories a reality.
Peer edited by Kaylee Helfrich.
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