CARDIAC AND VASCULAR BIOLOGY
The human heart is composed of a many elements that work synonymously with one another to pump blood throughout the entire body to bring clean, oxygenated blood to tissues in exchange for waste materials that must be filtered and removed via the hepatic, pulmonary, and renal systems. There are 4 muscular chambers housed within the heart, the left and right atria and ventricles, along with 4 valves that direct blood flow through the heart: the tricuspid valve, pulmonary valve, mitral valve, and aortic valve. All is enclosed within a membranous sac called the pericardium.
Muscle within the heart is unique, in that is the only muscle in the body that can conduct its own electrical impulses to induce contraction of the tissue. This powers blood flow throughout the entire arterial system, allowing fresh blood to reach all organs and tissues to keep them functioning properly. The vascular system consists of veins, venules, arteries, arterioles, and capillaries that are all connected via the heart. Human vasculature is made up of layers of endothelium that have various functions to ensure appropriate mechanics of blood flow and gas exchange. One of the challenges of recreating this tissue type is recapitulating the function of each layer to engineer a fully functional vessel that can:
- Maintain it’s strength and durability under sustained stress and fatigue
- Maintain unidirectional blood flow
- Produce anti-thombotic signals to discourage clotting
- Withstand high-pressure circumstances
- Maintain contract and retract abilities
- Produce factors that make it capable of angiogenesis
The above reminds us that the intricacies of the human body are truly amazing and that all of its capabilities and functionalities are fascinating and highly complex. These complexities, however, are the challenges that scientists face when attempting to restore the function of an organ or tissue. Many scientists are working to regenerate or grow tissue that can repair or replace parts of the heart that have been damaged or deformed. Clinician researchers at UNMC fully understand the high demand for these types of tissues.
Dr. James Hammel is one of the few surgeons in the country who is able to perform successful pre and neo-natal allograft cardiovascular repair surgery. His research is focused on engineering a functional heart valve, specifically for children that does not harbor the complications listed above. He hopes to create a product that can stay with the child throughout their life, thereby eliminating the need for recurring open-heart surgery and valve replacements. The life span of the bioprostheses currently available is only 15-20 years. Therefore, a child receiving a valve at birth or even prenatally, may need up to 6 surgeries in their lifetime. He knows very well that each time someone undergoes this procedure their mortality risk increases as high as 20%.
Learn more about the Prosthetic Heart Valve Project