Featured Research

from universities, journals, and other organizations

MIT Technique Could Improve Cartilage Repair

Date:
July 18, 2002
Source:
Massachusetts Institute Of Technology
Summary:
MIT engineers are excited about a new technique for repairing cartilage that could have significant advantages over the procedure now commonly used. This could affect people disabled by osteoarthritis, which slowly destroys the tissue that cushions joints. Hundreds of thousands others damage cartilage through sports-related injuries and other accidents.

CAMBRIDGE, Mass. -- MIT engineers are excited about a new technique for repairing cartilage that could have significant advantages over the procedure now commonly used. This could affect people disabled by osteoarthritis, which slowly destroys the tissue that cushions joints. Hundreds of thousands others damage cartilage through sports-related injuries and other accidents.

The new technique involves growing cartilage cells within a novel "designer" gel outside the body, then ultimately delivering the cell-seeded gel into a damaged joint. The idea is that the tissue will grow and integrate with the normal cartilage surrounding it while the gel slowly degrades, leaving behind a functioning tissue.

The researchers describe the first promising steps toward this goal in the issue of the Proceedings of the National Academy of Sciences published online the week of July 15-19. Although the engineered tissue has yet to be tested in animals, "it has mechanical and biochemical properties near to those of native cartilage," said Alan Grodzinsky, a professor with appointments in the Biological Engineering Division, the Department of Electrical Engineering and Computer Science and the Department of Mechanical Engineering.

"The implication is that the [new] gel provides a suitable environment for encapsulation of cartilage cells, with the goal of creating an implant that may be used to repair cartilage defects," said John Kisiday, first author of the paper and a graduate student in the Biological Engineering DIvision.

Kisiday and Grodzinsky's coauthors are former mechanical engineering graduate student Moonsoo Jin; Bodo Kurz; Han-Hwa Hung, a member of the research staff at MIT's Center for Biomedical Engineering (CBE); Carlos Semino, a CBE research scientist; and Shuguang Zhang, CBE associate director. Grodzinsky is director of the CBE.

Repairing defects

There is currently only one procedure approved by the U.S. Food and Drug Administration for repairing cartilage defects. It involves extracting a small amount of cartilage cells from a patient, coaxing them to multiply outside the body, and then implanting the new cells into the damaged area.

But the procedure "is expensive, with a total cost of around $30,000," Grodzinsky said, "and it does not result in the generation of a true articular cartilage." The only other treatment for late-stage osteoarthritis is to replace the affected joint with an artificial one, a procedure "that most surgeons prefer not to perform on patients younger than about 60 years of age, since joint replacements have a finite lifetime," he said. According to the American Academy of OrthopaedicSurgeons, more than 442,000 joint replacement procedures are performed each year in the United States.

The MIT team is hopeful that the "cartilage gel" could be implanted arthroscopically, through a small external incision. Such minimally invasive surgery is not only less expensive, but "reduces the recovery time for the patient," Grodzinsky said.

In 1993, Zhang discovered that proteins in the human body, when in fragments called peptides, can be tweaked to self-assemble into completely new natural materials (MIT Tech Talk, April 28, 1993). Since then, he and others have tailored such peptides to create everything from novel "nanosoaps" (MIT Tech Talk, April 3, 2002) to biomedical devices and industrial fluids.

In addition, said Zhang, "It is believed that the peptide scaffold hydrogel is generally useful for a wide range of cell/tissue types for regenerative biology and medicine." Indeed, cartilage is only the latest tissue to grow on such scaffolds. They have also been used to support nerve cells and tissues including bone and liver.

Many advantages

"There are a number of materials being studied for use as scaffolds in tissue engineering, but this hydrogel has properties that make it an important candidate," said Grodzinsky.

Zhang noted that the peptide hydrogel is made of interwoven fibers only 10-20 nanometers (billionths of a meter) in diameter. "This is in sharp contrast to other biopolymer microfibers, which are some 1,000 times larger in diameter," he said.

"That smaller size scale makes all the difference in the world," Zhang continued. For example, growth factors could be tethered to the peptide structure of the gel to directly stimulate the cartilage cells.

The hydrogel is also biocompatible and can be tailored to have different properties. By choosing an exact sequence of peptide building blocks, for example, the gel could be designed to degrade over a specific time frame. There is also less risk of passing along viruses to the engineered tissues because the peptide is not extracted from animal tissues, which can sometimes be a source of such pathogens.

Cartilage is unusual in that its cells make up less than 10 percent of the overall tissue. The rest of the tissue is composed of a stiff, spongy matrix produced by those cells. So "a major challenge in choosing an appropriate scaffold for cartilage repair," wrote the authors, is identifying a material that can simultaneously stimulate the cells themselves to multiply while coaxing them to produce more matrix. The hydrogel fosters both, they reported.

Exercise regimen

Scientists also know that cartilage production and degradation are regulated in part by the physical forces or loads put on cartilage as we stand or walk, for example. Similarly, physical forces are also key to the growth and mechanics of engineered cartilage.

To that end, Kisiday has identified mechanical "exercising" conditions that, when applied to the cartilage-seeded hydrogel over several weeks, "increased repair tissue formation and also the mechanical properties of the growing tissue." He reported these results at a June meeting of the International Cartilage Repair Society.

The combination of the peptide scaffold and Kisiday's "exercise regimen" has resulted in a "very appropriate cartilage-like tissue," Grodzinsky said. Several challenges remain, however. For example, at what point do you implant a growing scaffold into the body, and let the joint motion in an animal or human carry development to the final state? "People are just facing that issue now," he said.

The MIT team and others continue to optimize the hydrogel for growing cartilage and other tissues. "Something good is going to come from this--hopefully for our joints," Grodzinsky said.

The work is funded by the NIH and the DuPont-MIT Alliance.


Story Source:

The above story is based on materials provided by Massachusetts Institute Of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute Of Technology. "MIT Technique Could Improve Cartilage Repair." ScienceDaily. ScienceDaily, 18 July 2002. <www.sciencedaily.com/releases/2002/07/020718074955.htm>.
Massachusetts Institute Of Technology. (2002, July 18). MIT Technique Could Improve Cartilage Repair. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2002/07/020718074955.htm
Massachusetts Institute Of Technology. "MIT Technique Could Improve Cartilage Repair." ScienceDaily. www.sciencedaily.com/releases/2002/07/020718074955.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins