How often do you give thought to your heart? As long as your heart is beating properly and without pain, most of us are unconcerned with how doctors, scientists and engineers study the heart, diagnose problems, and create solutions to conditions and maladies that affect the heart.

When something goes wrong with the heart, doctors are able to diagnose the problem based on knowledge supplied by science. The tools doctors use to diagnose the problem (such as ultrasound, the electrocardiogram (EKG), the stethoscope and blood pressure machine) and then treat the problem (via stents, pacemakers, replacement valves and drugs) come from a field called bioengineering. Let’s take a look at how the broad field of bioengineering helps us when our heart is not at its best. By definition, bioengineering can be considered a combination of any field of engineering mixed with any field of biology, in any proportion.

First, let’s meet some biologists. I could not possibly list every type of biology involved in exploring our fascinating bodies, but thought this list will provide an overview of the levels with which one can study the heart.

An anatomist is someone who examines the heart structure at what we call the “gross” level, meaning at the level perceptible to the human eye. They know all of the nerve supply, the blood vessels large and small (remember the aorta and the vena cava?), which are connected in about the same location on each heart of the same species, allowing blood to flow in and out of the muscular chambers (ventricles and auricles), separated by valves (for instance, the mitral valve). Your physician, surgeon and cardiologist also know these things.

A physiologist is concerned with the functioning of the heart: how quickly and at what pressure and tempo blood is sent through the body by the synchronized beating of the heart chambers. They understand how the electrical signal passes through the muscle to coordinate a proper rhythm and how drugs and hormones can affect these activities.

A histologist, which is what I consider myself foremost, looks at the heart with a microscope and can discern what is different about the heart tissue in comparison to other tissues of the body. A histologist looks at cardiac muscles and can see “lines” at junctions between cells. These lines represent the place where heart cells are tightly knitted together and also where chemicals pass between cells so the cells know to beat at the same time as the rest of the organ. Most often, a histologist will also be a cell biologist who understands how individual cells work AND work with other cells to create a functioning organ.

A cell biologist often manipulates cells that have been isolated from heart tissue and grows them in a special nutrient liquid at appropriate temperatures to keep them alive for a long time. This technique is called cell culture, another one of my areas of expertise. A cell biologist understands the various proteins and the organelles in the cell and that different cell types will vary in the amount and type of proteins they create and use, as well as how the surrounding environment impacts the growth and development of the cells.

A biochemist understands the multiple enzyme and chemical pathways that work to help make heart cells resistant to fatigue. A molecular biologist concerns themselves with how the DNA and RNA in the cell creates the proteins and directs them to the proper place in the cell, whether it be in the cytoplasm, in organelles or on the cell membrane.  Both of these fields are extremely important for pharmaceutical researchers to understand so they can create drugs that properly target problems at the molecular level.

At each of these levels, from gross to molecular, there is potential to manipulate the heart to heal problems Engineers solve problems using the insights gained from science. Part of the challenge engineers face is to also be able to create their products at a reasonable price.

If something is severely wrong with a heart, perhaps one can receive a heart transplant from a recently deceased donor. Organ donors are in small numbers and the transplant is always under risk of rejection and infection. Powerful drugs, designed by pharmaceutical engineers and produced by chemical engineers are required to keep the new heart from being rejected by the immune system.

Given the shortage of donors, scientists and doctors have considered the potential benefit of creating an artificial heart, made of plastic and metal, and possibly even biosynthetic materials that are much more like flesh, mimicking the most important functions of the heart. Using the knowledge of anatomists and physiologists, engineers have attempted the creation of an artificial heart, which is often used to carry the patient over until a human transplant can occur.

Mechanical engineers know how to properly create and combine moving parts and understand the dynamics of fluid flow, so pumping strength and frequency is adequate to deliver blood through the body. Materials scientist design and test various plastics and metals (and biosynthetic materials) for efficient functioning, long wear and compatibility with the body so the device does not cause more problems than it is trying to solve. Electrical engineers and computer engineers collaborate to supply power to the heart and install electrical sensors so doctors can be made aware of the functioning of the artificial heart remotely.

We are a long way off from using the patient’s cells to grow a new heart in the laboratory, as the heart is very complex, but some organs have been grown in the lab, including skin and bladder, so the potential exists. It is the diligent work of tissue engineers that might make this a possibility in the future.

What if a heart transplant is not needed and perhaps only the rhythm of the heart needs to be regulated? Using knowledge of the physiology of electrical signals normally present in the healthy heart to help contract the heart muscle, engineers have designed the artificial pacemaker, a device that contains electrodes that regulate the beating of the heart. Sometimes these pacemakers also contain a defibrillator that can restart the heart should it temporarily fail.  Again, the design of a pacemaker requires the knowledge of material scientists, and electrical and computer engineers.

Heart attacks occur when arteries that feed the muscle of the heart are blocked. Engineers have designed devices, inserted by surgeons, called stents that open blocked blood vessels. Newer stent version have special protein or drug coatings that prevent future blood clots, which is a very common side effect of placing artificial materials in contact with blood. Creating these devices requires mechanical engineering, materials science, and biochemical knowledge.

Sometimes doctors choose to replace those arteries in a bypass operation, taking part of a long vein in the leg. Veins do not pose the same blood clotting issues as stents but still are architecturally different than arteries (speaking as a histologist) The walls of veins are weak and cannot handle the stronger blood pressure that moves through arteries, and veins will fail after about 10 years of pretending to be an artery, requiring future surgeries. Tissue engineers and materials scientists are attempting to design replacement arteries from innovative materials and some of the patient’s own cells.

When the heart sustains damage from a heart attack, the damaged muscle is quickly filled in with scar tissue. Is there a way to regain the youthful heart muscle after such assault? Scientists and engineers are looking at ways to either supplement the muscle with a new patch of cells on a scaffold of novel plastic or other materials that can be placed on the area of damage. Some scientists look to use stem cells (the topic of a future article) added to the site of injury which can transform into heart muscle, effectively healing the area.  Pharmaceutical engineers are interested creating in drugs that can stimulate cells in the area of injury to become healthy heart muscle.

Universities across the world are adding bioengineering departments and courses to their offerings and are creating opportunities for students and researchers to collaborate across biology and engineering disciplines.  This article only explained bioengineering as it relates to the heart, but this exciting field has applications to any body part or system. The next time you get your blood pressure checked or have an X-ray, remember that you have scientists, engineers AND your doctor to thank for their expertise!

Joanne Manaster is a Faculty Lecturerat the  School of Integrative Biology, University of Illinois, Urbana
She is also known as @sciencegoddess on Twitter

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Comments

1. Hannah Holmes - Author 16/12/2010

   Very cool! I hope I never need this technology and expertise applied to my person, but it is nonetheless awesome and amazing what we can do.

2. Patty OBrien Novak - Author/Engineer 21/12/2010

   What a great article highlighting how engineers, scientists and doctors work together to save lives and help make miracles happen! Too often engineers are lumped into the scientist category – this posting shows just how different are the role of scientist and engineer.