Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oxygen key switch in transforming adult stem cells from fat into cartilage

03.02.2003


In their ongoing research on turning adult stem cells isolated from fat into cartilage, Duke University Medical Center researchers have demonstrated that the level of oxygen present during the transformation process is a key switch in stimulating the stem cells to change.

Their findings were presented today (Feb. 2, 2003) at the annual meeting of the Orthopedic Research Society.

Using a biochemical cocktail of steroids and growth factors, the researchers have "retrained" specific adult stem cells that would normally form the structure of fat into another type of cell known as a chondrocyte, or cartilage cell. During this process, if the cells were grown in the presence of "room air," which is about 20 percent oxygen, the stem cells tended to proliferate; however, if the level of oxygen was reduced to 5 percent, the stem cells transformed into chondrocytes.



This finding is important, the researchers say, because this low oxygen level more closely simulates the natural conditions of cartilage, a type of connective tissue that cushions many joints throughout the body. However, since it is a tissue type poorly supplied by blood vessels, nerves and the lymphatic system, cartilage has a very limited capacity for repair when damaged. For this reason, the Duke investigators are searching for a bioengineering approach to correct cartilage injury.

"Our findings suggest that oxygen is a key determinant between proliferation and differentiation, and that hypoxia, or low oxygen levels, is an important switch that tells cells to stop proliferating and start differentiating,’ said David Wang, a fourth-year medical student at Duke, who presented the results of the Duke research.

Farshid Guilak, Ph.D., director of orthopedic research and senior member of the Duke team, said that the combination of growth factors sets the adult stem cells on the right path, while controlling oxygen levels inspires the cells to more readily transform into chondrocytes. Without the growth factors, he said, changing oxygen levels has no effect on the cells.

"For us, the ultimate goal is the development of a bioreactor where we can very carefully control the physical and chemical environment of these cells as they transform," Guilak said. "The results of these experiments which demonstrated the role of oxygen levels in the process represent another important step in achieving this goal."

Two years ago at the Orthopedic Research Society meeting, the Duke team for the first time reported that cartilage cells can be created from fat removed during liposuction procedures. Not only were the researchers able to make cells change from one type into another, they grew the new chondrocytes in a three-dimensional matrix, a crucial advance for success in treating humans with cartilage damage.

In their latest experiments, the team used the materials collected from liposuction procedures performed on multiple human donors. These materials were then treated with enzymes and centrifuged until cells known as adipose-derived stromal cells remained. These isolated cells were infused into three-dimensional beads made up of a substance known as alginate, a complex carbohydrate that is often used as the basis of bioabsorbable dressings, and then treated with the biochemical cocktail.

Those cells grown in hypoxic conditions saw growth inhibited by as much as 44 percent, but saw as much as an 80 percent increase in chondrocyte differentiation.

"No one has looked at the role of hypoxia in the creation of chondrocytes, but it made sense since cartilage normally exists in an hypoxic environment," Wang said. "While we know oxygen plays a role, we don’t know the mechanism. The next questions to answer are how the cells sense the level of oxygen around them and then turn that into a metabolic change."

The researchers anticipate that the first patients to benefit from this research would be those who have suffered some sort of cartilage damage due to injury or trauma. Farther down the line, they foresee a time when entire joints ravaged by osteoarthritis can be relined with bioengineered cartilage.

"We don’t currently have a satisfactory remedy for people who suffer a cartilage-damaging injury," Guilak said. "There is a real need for a new approach to treating these injuries. We envision being able to remove a little bit of fat, and then grow customized, three-dimensional pieces of cartilage that would then be surgically implanted in the joint. One of the beauties of this system is that since the cells are from the same patients, there are no worries of adverse immune responses or disease transmission."

The Duke researchers have developed several animal protocols to test how this cartilage fares in a living system.


The research was supported by the National Institutes of Health; Artecel Sciences, Inc., Durham, N.C.; the North Carolina Biotechnology Center, Research Triangle Park, N.C.; and the Kenan Institute for Engineering, Technology, and Science at North Carolina State University, Raleigh, N.C.

Joining Wang and Guilak in the research were Beverley Fermor, Ph.D., from Duke, and Jeff Gimble, M.D., from Artecel Sciences.

Richard Merritt | EurekAlert!
Further information:
http://www.mc.duke.edu/

More articles from Life Sciences:

nachricht Cells migrate collectively by intermittent bursts of activity
30.09.2016 | Aalto University

nachricht The structure of the BinAB toxin revealed: one small step for Man, a major problem for mosquitoes!
30.09.2016 | CNRS (Délégation Paris Michel-Ange)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.

Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Paper – Panacea Green Infrastructure?

30.09.2016 | Event News

HLF: From an experiment to an establishment

29.09.2016 | Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

 
Latest News

First-Ever 3D Printed Excavator Project Advances Large-Scale Additive Manufacturing R&D

30.09.2016 | Materials Sciences

New Technique for Finding Weakness in Earth’s Crust

30.09.2016 | Earth Sciences

Cells migrate collectively by intermittent bursts of activity

30.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>