Lindau Lecture by Louis Joseph Ignarro: Nitric Oxide: the Miracle Molecule of Health and Longevity

Louis Joseph Ignarro

Nitric oxide (NO) is a gaseous molecule found in the earth’s atmosphere, and its source is air pollution and lightning storms. NO, itself, is nontoxic but it is rapidly oxidized to nitrogen dioxide (NO2), which is deadly toxic. Biologists began studying NO in the laboratory in the late 1970s, and found that it dilated arteries and veins, resulting in a drop in blood pressure and an increase in local blood flow to tissues. NO was also found to prevent excessive blood clotting or thrombosis. During these studies, NO was not known to exist in mammalian cells, and was studied just an interesting chemical. However, in 1986, my laboratory discovered that NO does indeed exist in cells and can be produced in the endothelial cells lining all arteries. Further studies revealed that endothelium-derived NO works to control our blood pressure, regulate blood flow throughout the body, and prevent the blood from clotting in undesirable locations, such as the coronary arteries and the brain. Shortly afterwards, in 1992, we reported that NO is also a neurotransmitter released from the nerves that promote penile erection and sexual arousal. Before this finding, the neurotransmitter was unknown and the cause of erectile dysfunction remained a complete mystery. There were no drugs available to treat erectile dysfunction. Our discovery made it possible for drug industry to develop a drug that increases the actions of NO in the erectile tissue, thereby, allowing penile erection to occur in impotent males. This drug is known to all as the "little blue pill", VIAGRA. Nitric oxide turned out to be a widespread signaling molecule that plays a diverse role in regulating many physiological processes. As a result of this exciting basic research by many scientists, the Nobel Prize in Physiology or Medicine was awarded, in 1998, to the three pharmacologists who pioneered the early work on nitric oxide. These were: Ferid Murad, Robert Furchgott, and Lou Ignarro. Since then, a myriad of new discoveries have been made that reveal the therapeutic benefits of inhaling NO gas. For example, inhaled NO gas, available commercially, is administered to newborn babies to reverse pulmonary hypertension brought on by anatomical defects in the heart and lungs during birth. In addition, inhaled NO has been used successfully to treat patients with COVID-19. NO works by dilating the airways and pulmonary arteries, and killing the SARS-CoV-2 virus that causes COVID-19. I am always impressed with the multitude of diverse protective effects of NO in our bodies. This is why I view nitric oxide as the "Miracle Molecule of Health and Longevity."

To signify the close bond between the Lindau Nobel Laureate Meetings and the Heidelberg Laureate Forum, each year a laureate is selected to give a guest lecture at the respective meeting. This year’s Lindau Lecture is given by Louis Joseph Ignarro, who received the Nobel Prize in Physiology or Medicine in 1998 together with Robert F. Furchgott and Ferid Murad for their discoveries concerning nitric oxide as a signalling molecule in the cardiovascular system.