Navigation Links
A strategy to fix a broken heart
Date:8/9/2010

These days people usually don't die from a heart attack. But the damage to heart muscle is irreversible, and most patients eventually succumb to congestive heart failure, the most common cause of death in developed countries.

Stem cells now offer hope for achieving what the body can't do: mending broken hearts. Engineers and physicians at the University of Washington have built a scaffold that supports the growth and integration of stem cell-derived cardiac muscle cells. A description of the scaffold, which supports the growth of cardiac cells in the lab and encourages blood vessel growth in living animals, is published this week in the Proceedings of the National Academy of Sciences.

"Today, if you have a heart attack there's nothing that doctors can do to repair the damage," said lead author Buddy Ratner, a UW professor of bioengineering. "You are, in essence, sentenced to a downhill slide, developing congestive heart failure that greatly shortens your lifespan.

"Your body can't make new heart cells, but what if we can deliver vital new cells in that damaged portion of the heart?"

Ratner and his colleagues built a tiny tubular porous scaffold that supports and stabilizes the fragile cardiac cells and can be injected into a damaged heart, where it will foster cell growth and eventually dissolve away. The new scaffold not only supports cardiac muscle growth, but potentially accelerates the body's ability to supply oxygen and nutrients to the transplanted tissue. Eventually, the idea is that doctors would seed the scaffold with stem cells from either the patient or a donor, then implant it when the patient is treated for a heart attack, before scar tissue has formed.

Other heart scaffolds or tissue patches currently being developed combine cardiac muscle cells and two other types of cells needed to kick-start the growth of blood vessels and connective tissue. Preparing each type of cells is an enormous amount of work, so a scaffold that requires just one type of cell, like this one, would be significantly cheaper and easier to use.

Ratner's scaffold is a flexible polymer with interconnected pores all of the same size. This one also includes channels to accommodate cardiac cells' preference for fusing together in long chains. Researchers first verified the design using chicken embryonic heart cells, and confirmed that the scaffold could support heart tissue growth at concentrations similar to those in living heart tissue.

They then seeded the scaffold with cardiac muscle cells derived from human embryonic stem cells. These cells survived and collected in the channels. Over five days, the cardiac muscle cells multiplied faster in the scaffold environment than other cell types, and could survive up to 300 micrometers (about the diameter of four human hairs) from the scaffold edge an important point if the scaffold is to integrate with the body.

The cells expressed two proteins associated with muscle contraction and could contract with sufficient force to deform the scaffold.

Researchers also implanted a bare scaffold into a living rat's heart to verify the scaffold's biocompatibility. Results showed that after four weeks the heart had accepted the foreign body, and new blood vessels had penetrated into the scaffold.

Why blood vessels penetrate so well is unknown. One hypothesis involves the macrophage, a cell in the immune system, and the size of the pores, which seems to be critical. The macrophages first attack the foreign body as an invader and try to digest it. They enter the pores and are themselves entrapped. At this point the macrophage seems to switch from its attack mode to its healing mode. The team is now investigating the blood vessel formation.

Heart tissues need a rich blood supply, and that's been one of the limiting factors to heart repair and vascular tissue engineering, said co-author Chuck Murry, professor of pathology and bioengineering.

"The first thing that transplanted heart cells have to do is survive. And when you transition them from a culture dish to the body, initially they don't have a blood supply. So we have to promote the host blood supply as fast as possible," Murry said.

"We're very optimistic that this scaffold will help keep the muscle cells alive after implantation and will help transition them to working heart muscles," Murry said.

The scaffold is made from a jelly-like hydrogel material developed by first author, UW bioengineering doctoral student Lauran Madden. A needle is used to implant the tiny (third of a millimeter wide by 4 millimeters long) scaffold rods into the heart muscle. But the scaffold can support growth of larger clumps of heart tissue, Madden said.

The next steps will involve adjusting the scaffold degradation time so that the scaffold degrades at the same rate that cardiac cells proliferate and that blood vessels and support fibers grow in, and then implant a cell-laden scaffold into a damaged heart.

"What we have now is a really good system going in the dish, and we're working to transition it to in the body," Madden said.

Beat BioTherapeutics, a Seattle startup co-founded by Ratner, Murry and co-author Michael Laflamme, a UW assistant professor of pathology, plans to license the technology to help bring it to patients.


'/>"/>

Contact: Hannah Hickey
hickeyh@uw.edu
206-543-2580
University of Washington
Source:Eurekalert  

Related biology news :

1. UM School of Medicine scientists develop new strategy that may improve cognition
2. Molecular discovery suggests new strategy to fight cancer drug resistance
3. Scientists call for a new strategy for polar ocean observation
4. Flus evolution strategy strikes perfect balance
5. A new effective strategy for treating tobacco addiction was developed by researchers from the CAS
6. Physics strategy tested as solution for antibiotic resistance
7. Novel strategy for generating induced pluripotent stem cells for clinical use is safe and efficient
8. Global study shows health joins green as business strategy
9. Novel Parkinsons treatment strategy involves cell transplantation
10. Study highlights forest protected areas as a critical strategy for slowing climate change
11. Plants discover the benefits of good neighbors in strategy against herbivores
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
A strategy to fix a broken heart
(Date:4/17/2017)... MELBOURNE, Florida , April 17, 2017 ... security technology company, announces the filing of its 2016 Annual Report ... Securities and Exchange Commission. ... Report on Form 10-K is available in the Investor Relations section ... well as on the SEC,s website at http://www.sec.gov . ...
(Date:4/11/2017)... BROOKLYN, N.Y. , April 11, 2017 /PRNewswire-USNewswire/ ... identical fingerprints, but researchers at the New York ... University College of Engineering have found that partial ... fingerprint-based security systems used in mobile phones and ... previously thought. The vulnerability lies in ...
(Date:4/5/2017)... 2017 KEY FINDINGS The global ... a CAGR of 25.76% during the forecast period of ... factor for the growth of the stem cell market. ... MARKET INSIGHTS The global stem cell market is ... geography. The stem cell market of the product is ...
Breaking Biology News(10 mins):
(Date:8/16/2017)... ... 16, 2017 , ... While art and science are often thought of as ... might think. A Mesh Is Also a Snare, a group exhibition presented by ... Esther Klein Gallery (EKG) on August 17 and run through September 30. An opening ...
(Date:8/16/2017)... and OXFORD, England , Aug. ... -based consortium for biotech executive search and leadership development, and ... Healthcare sectors, have created an exclusive alliance that enables clients ... "For our clients here in ... provides unparalleled access to a diverse population of leadership talent ...
(Date:8/15/2017)... ... 15, 2017 , ... Pittcon is pleased to once again ... instruments. This year’s symposium, organized by the Pittcon 2018 program chair, Annette Wilson, ... This dynamic presentation will discuss novel ionization processes, high throughput IMS-MS technologies, and ...
(Date:8/15/2017)... , ... August 15, 2017 , ... ... is threatened by various biotic and abiotic factors. During this educational webinar, participants ... of coffee, as well as gain a better understanding of how genomics is ...
Breaking Biology Technology: