Bioengineered hearts are coming fast
According to researchers at the University of Michigan (U-M), we can now engineer prototypes of all cardiovascular structures: heart muscle, tri-leaflet valves, blood vessels, cell-based cardiac pumps and tissue engineered ventricles. In fact, they wrote that it's possible today to engineer the heart piece by piece. But they also noted that "hurdles still remain before the products of this tissue engineering are ready to be implanted in patients as replacements for diseased or malformed structures."
Here are some examples of the technologies which can be used today. From top to bottom, the diagram on the left illustrates how these bioengineering technologies could be used for patients suffering respectively from acute myocardial infarction, atherosclerosis, heart valves failures and end-stage hart failures (Credit: U-M and Regenerative Medicine). Here is a link to a full version of this diagram.
These technologies have been analysed by Ravi Birla, director of the U-M Artificial Heart Laboratory, and by Louise Hecker, a graduate student in the U-M Department of Cell & Developmental Biology. They've not only looked at what was happening at U-M, but in other labs worldwide.
Their article has just been published by Regenerative Medicine under the title "Engineering the heart piece by piece: state of the art in cardiac tissue engineering" (March 2007, Volume 2, Number 2, Pages 125-144). If you're not a subscriber, you'll need to pay $50 to read this article. But here is a link to the abstract.
Of course, the paper privileges U-M successes, like the results obtained last year in growing bioengineered heart muscle, or BEHM. The researchers used "a fibrin hydrogel, that is faster than others, but still yields tissue with significantly better properties. The gel was able to support rat cardiac cells temporarily, before the fibrin broke down as the cells multiplied and organized into tissue within a few days. Tests showed that the BEHM was capable of generating pulsating forces and reacting to stimulation more like real muscle than ever before.
For more information, you can read "A new approach to growing heart muscle" (U-M news release, December 7, 2006). This research work has been published by the Journal of Biomedical Materials Research A under the title "Contractile three-dimensional bioengineered heart muscle for myocardial regeneration" (Volume 80A, Issue 3, Pages 719-731, published online December 7, 2006). Here is a link to the abstract.
But the new paper by Birla and Becker "also details many other discoveries that have been made by other teams using different cell-growing surfaces and conditions, as well as hurdles that still lie ahead. In all, the authors say, bioengineered cardiac tissue holds immediate promise as a way to study heart disease and its treatment in cell cultures -- and promise over the longer term as a source of new patient treatments."
Sources: University of Michigan Medical School press release, via EurekAlert!, March 27, 2007; and various websites
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