Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stretching bone marrow stem cells pushes them towards becoming blood vessel

26.10.2006
When stretched, a type of adult stem cell taken from bone marrow can be nudged towards becoming the type of tissue found in blood vessels, according to a new study by bioengineers at the University of California, Berkeley.

Researchers placed mesenchymal stem cells onto a silicone membrane that was stretched longitudinally once every second. It was a cellular workout routine that helped point the bone marrow stem cell in the direction of becoming the smooth muscle tissue of vascular walls.

The findings, published today (Monday, Oct. 23) in the online early edition of the Proceedings of the National Academy of Sciences, highlight the importance of mechanical forces in stem cell differentiation.

Mesenchymal stem cells have the ability to turn into different types of connective tissue including bone, cartilage and muscle. Embryonic stem cells have the advantage of being able to turn into any kind of body tissue and of being easier to work with in the lab, though that flexibility comes with controversy and ethical questions not found in research on adult stem cells.

But research on both types of stem cells holds the promise of treatment for diseased or damaged body parts. Experiments in stem cell differentiation, however, have traditionally relied upon chemical signals to prompt this transformation into the desired cell type.

Song Li, UC Berkeley associate professor of bioengineering and principal investigator of the study, heads one of the leading research groups in the country investigating the role of a stem cell's physical environment on its development.

"The mechanical effects on the body are well known. A good example is when astronauts in space experience a loss of bone mass because there is no gravity," said Li. "We are now extending this concept to the cellular level by showing that mechanical stimulation can impact stem cell differentiation."

In an effort to better understand the factors that affect the eventual fate of mesenchymal stem cells, the researchers designed the experiment to simulate the physical forces a cell would encounter if it were to become a blood vessel.

Kyle Kurpinski, a UC Berkeley graduate student in bioengineering and lead author of the study, noted that in previous studies on the effects of mechanical strain, cells were stretched in all directions. However, he pointed out that cells in the walls of a blood vessel are pulled in a circumferential direction, or sideways if the vessel walls are laid flat. This new study is the first to look at the effects of such uniaxial strain on stem cell differentiation.

A one-stretch-a-second pace was chosen to correspond to a typical adult pulse rate, said Kurpinski. The researchers placed a single layer of mesenchymal stem cells onto a membrane with microgrooves to resemble the patterns formed in blood vessels by collagen fibers.

The microgrooves were aligned either perpendicular or parallel to the axis of strain, and some of the cells were stretched while others were not. The researchers also looked at the effects of stretching stem cells on a smooth membrane with no microgrooves.

"It is hypothesized that cells aligned in the microgrooves actually feel the strain of the pull more than if they were on a smooth surface," said Kurpinski.

After two days of this cellular exercise regimen, the researchers found a significant increase in the expression of a group of genes that control tensile strength compared with cells that were not stretched. Tensile strength is important for tissue that must withstand pulling forces, such as in vascular walls. Specifically, there was an increased level of calponin 1, a genetic marker for smooth muscles.

At the same time, expression of a group of genes associated with compression-bearing tissue, such as cartilage and bone, decreased. "For cartilage and bone, particularly at the joints, cells experience compression forces," said Li. "Stem cells seem to know the type of tissue they are supposed to become by the type of mechanical strain they are subjected to."

As for cell positioning, the researchers found that without the microgrooves, the stem cells would align themselves perpendicularly to the direction of the stretch. In contrast, when stretched on a membrane with microgrooves parallel to the axis of strain, the stem cells aligned themselves along the grooves.

They found that the perpendicular orientation significantly diminished the expression of genes for tensile strength. Researchers also saw a slight increase in cell proliferation when cells were aligned parallel to the axis of strain.

The findings indicate that the stem cells were well on their way to becoming smooth muscle tissue, although they didn't quite get there.

"The potential is there," said Li. "We are halfway done. To completely achieve the efficient guidance of cell differentiation in a lab, we will likely need a combination of chemical and mechanical factors."

"We're definitely a major step closer to developing a process of tissue engineering that could one day have clinical applications," added Kurpinski.

Sarah Yang | EurekAlert!
Further information:
http://www.berkeley.edu

Further reports about: Kurpinski Membrane aligned blood vessel marrow mechanical microgrooves stem cells vessel

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>