It appears a process called whole organ decellularization may contribute to a solution — essentially using nature’s platform to create a bioartifical heart, according to Taylor, a professor of medicine and physiology. Decellularization is the process of removing all of the cells from an organ — in this case an animal cadaver heart — leaving only the extracellular matrix, the framework between the cells, intact.

Taylor says that while there have been advances in generating heart tissue in the lab, creating an entire 3-dimensional scaffold that mimics the complex cardiac architecture and intricacies, has always been a mystery.

 

Substantial previous research, sponsored by the US National Aeronautics and Space Administration (NASA) and others, emphasized the use of biolpolymers to create 3D scaffolding. That work was useful in defining the problem and offering a model for natural materials.

 

"We knew that cell therapy — that is, transplanting cells into the heart — is not a panacea. So we started thinking, 'Is there a way to use cells to engineer heart tissue?'"

 

The team is also experimenting with pig hearts, which are about the same size as human hearts, and have successfully generated ECM's from them.

 

“We used immature heart cells in this version, as a proof of concept. We pretty much figured heart cells in a heart matrix had to work,” Taylor said. “Going forward, our goal is to use a patient’s stem cells to build a new heart.”

 

Someday, doctors may routinely extract cells from heart failure patients and use them to reseed a new organ from a cadaver-derived ECM. What types of cells those would be isn't known yet. "It depends on what cells are best," says Taylor. "Bone marrow-derived stem cells are already used to treat hearts. It may be a mix of cells from bone marrow, hearts and skeletal muscle. We'll use whatever cells we think are going to give us the best shot."

Doris Taylor, Ph.D., Medtronic Bakken professor of medicine and physiology, directs the University of Minnesota Center for Cardiovascular Repair and is the principal investigator of the research. 

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Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart. Harald C Ott, Thomas S Matthiesen, Saik-Kia Goh, Lauren D Black, Stefan M Kren, Theoden I Netoff & Doris A Taylor. Nature Medicine. 2008. doi:10.1038/nm1684.

 

Abstract. About 3,000 individuals in the United States are awaiting a donor heart; worldwide, 22 million individuals are living with heart failure. A bioartificial heart is a theoretical alternative to transplantation or mechanical left ventricular support. Generating a bioartificial heart requires engineering of cardiac architecture, appropriate cellular constituents and pump function. We decellularized hearts by coronary perfusion with detergents, preserved the underlying extracellular matrix, and produced an acellular, perfusable vascular architecture, competent acellular valves and intact chamber geometry. To mimic cardiac cell composition, we reseeded these constructs with cardiac or endothelial cells. To establish function, we maintained eight constructs for up to 28 d by coronary perfusion in a bioreactor that simulated cardiac physiology. By day 4, we observed macroscopic contractions. By day 8, under physiological load and electrical stimulation, constructs could generate pump function (equivalent to about 2% of adult or 25% of 16-week fetal heart function) in a modified working heart preparation.