October 30, 2012
Stem Cell Study Probes Cartilage Injury and Osteoarthritis
Connie K. Ho for redOrbit.com — Your Universe Online
Researchers from Duke University Medical Center recently revealed that they have been able to engineer cartilage from pluripotent stem cells, which will help in studies regarding cartilage injury and osteoarthritis.
In particular, the pluripotent stem cells were induced and then successful developed to be used in tissue repair. The scientists believe that the induced pluripotent stem cells (iPSCs) could become a source for patient-specific particular cartilage tissue.
"This technique of creating induced pluripotent stem cells — an achievement honored with this year's Nobel Prize in medicine for Shinya Yamanaka of Kyoto University - is a way to take adult stem cells and convert them so they have the properties of embryonic stem cells," noted the study´s senior author Farshid Guilak, a professor of Orthopedic Surgery at Duke, in a prepared statement.
The researchers explained how articular cartilage acts as a shock absorber tissue in joints which helps people climb stairs, walk, jump and perform other activities without feeling any pain. Everyday use of joints or an injury can help decrease the effectiveness of the tissue and articular cartilage cannot be easily repaired. As such, damage and osteoarthritis are believed to be the main causes of impairment in older people and leads to people needing joint replacement surgeries.
"Adult stems cells are limited in what they can do, and embryonic stem cells have ethical issues," continued Guilak in the statement. "What this research shows in a mouse model is the ability to create an unlimited supply of stem cells that can turn into any type of tissue — in this case cartilage, which has no ability to regenerate by itself."
In the study, the scientists utilized recent technologies that targeted adult stem cells taken from the bone marrow or fat tissue. They worked to create a differentiated population of chondroyctes, which are cells found in healthy cartilage, that were still uniform. These cells could be used in the production of collagen and the maintenance of cartilage. In order to produce the specific cells, the researchers utilized iPSCs taken from adult mouse fibroblasts by using a culture that had been treated with a growth medium. The cells were also tailored to express green fluorescent protein when the cells had developed into chondrocytes. When the iPSCS differentiates, the chondrocyte cells that expressed the green fluorescent protein could be identified quickly. The researchers believe that the tailored cells also created larger amounts of cartilage components and displayed an ability to work well in repairing cartilage problems in the body.
"This was a multi-step approach, with the initial differentiation, then sorting, and then proceeding to make the tissue," explained Brian Diekman, a post-doctoral associate in orthopedic surgery, in the statement. "What this shows is that iPSCs can be used to make high quality cartilage, either for replacement tissue or as a way to study disease and potential treatments."
Moving forward, the researchers will focus on how to utilize human iPSCS to examine the cartilage-growing method.
"The advantage of this technique is that we can grow a continuous supply of cartilage in a dish," concluded Guilak in the statement. "In addition to cell-based therapies, iPSC technology can also provide patient-specific cell and tissue models that could be used to screen for drugs to treat osteoarthritis, which right now does not have a cure or an effective therapy to inhibit cartilage loss."
The findings are published online in the journal of the Proceedings of the National Academy of Sciences (PNAS).