Valentine’s Day! Heart-shaped cards, heart-shaped chocolates, conversation hearts, cards, roses and love are most commonly associated with this special day. But the beating muscular organ that keeps us alive gets lost in the shuffle. With Valentine’s Day nearly upon us, FBR is taking a moment to examine the ‘state of the heart’ – from how it came to symbolize love to how scientists and animals have improved heart health in modern times.

BigPinkHeartA Victorian-era Valentine’s Day card

So how did the heart, that continuously operating pump that sends blood throughout our circulatory system, become the go-to symbol for the complex emotion of love? Egyptians thought the heart was a moral compass, while ancient Greeks thought the heart contained the soul. Soon, people began drawing connections between the heart and love, first represented in the anonymous manuscript ‘Roman de la poire’ in the 1250’s. The heart as a symbol evolved into the shape we now know and became forever associated with love when people in 17th century England began celebrating Valentine’s Day and adding hearts to their many correspondences. Today the heart is a celebrity.

The heart is also a star in the daily business of keeping people and animals alive. It provides blood and oxygen to the rest of the body and removes waste. Without a heart you would definitely die – if your heart takes even a little break from its duties, you may well die. Clearly, it’s important to keep the heart healthy – something scientists working with animals have been doing for nearly a century. The first published article on animal research into the heart was “Experimental attempts to increase the blood supply to the dog’s heart by means of coronary sinus occlusion” (Gross et al.., 1937,) early research that helped to develop bypass surgery. By the 1950s, researchers were using both large and small mammals in heart research – see “Experimental Myocardial Infarction: I. A Method of Coronary Occlusion in Small Animals” (Johns et al.., 1954).

Perhaps the most influential heart surgeon was Dr. Michael DeBakey. In the late 1950s, Dr. DeBakey created a way to replace or repair blood vessels with Dacron fabric grafts. He spent two years sewing the first grafts himself and testing them in animals before successfully conducting the procedure in a person. In 1963 he conducted the first successful coronary bypass surgery, using the large vein in the leg to bypass the blocked or damaged areas between the aorta and coronary arteries. Dr. Debakey also worked with calves to develop the world’s first total artificial heart and went on to perform more than 60,000 surgical operations while also serving as chairperson of the Foundation for Biomedical Research’s board for many years. In 2008, Dr. DeBakey won the Congressional Gold Medal for his unparalleled work in heart sciences.

MicroMed-DeBakey_VAD_(ventricular_assist_device)_-_NASADr. DeBakey (right) holding the ventricular assist device he developed

The basics of heart disease treatment were created by scientists working on animal models. In order to perform many surgeries on a heart, you have to stop it from beating for a while so you can complete the delicate task at hand. Experiments with rats, rabbits and dogs established that potassium citrate will stop a heart from beating and that chilling the heart with cardioplegia would protect it while stopped. Rats, guinea pigs, rabbits and dogs were used to develop methods to replace heart valves, while pigs were used to develop minimally invasive techniques.

With these animal models, researchers have developed several new techniques for congestive heart failure. Working with sheep and pigs, doctors explored use of matrix metalloproteinase inhibition – enzymes that can help clear a congested heart. One of the more radical ideas has been the use of cells taken from a patient’s bone marrow that are transplanted into the heart in order to regrow diseased portions – a technique that was researched and perfected using pigs. Another team of researchers has developed a method of protein therapy that improved overall heart health dramatically – this team was also working with pigs.

As you can see, the history and future of heart disease treatment is inextricably connected to research with animals. If you know of any other interesting research we haven’t mentioned, please leave it in the comments below. As you celebrate this Valentine’s Day, don’t forget the strides medicine has made for the heart inside your chest while you’re unwrapping your heart-shaped box!

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