JOIN USResearchers have successfully engineered cartilage from induced pluripotent stem cells which can be used to repair body tissues.
A team of researchers from Duke Medicine suggest that induced pluripotent stem cells, or iPSCs, may be a viable source of patient-specific articular cartilage tissue.
"This technique of creating induced pluripotent stem cells – an achievement honoured with this year's Nobel Prize in medicine for Shimya Yamanaka of Kyoto University - is a way to take adult stem cells and convert them so they have the properties of embryonic stem cells," said researcher Farshid Guilak.
"Adult stems cells are limited in what they can do, and embryonic stem cells have ethical issues," Guilak said.
"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," said Guilak.
Articular cartilage is the shock absorber tissue in joints that makes it possible to walk, climb stairs, jump and perform daily activities without pain.
However, ordinary wear-and-tear or an injury can diminish its effectiveness and progress to osteoarthritis.
Because articular cartilage has a poor capacity for repair, damage and osteoarthritis are leading causes of impairment in older people and often requires joint replacement.
The Duke researchers, led by Brian O Diekman, aimed to apply recent technologies that have made iPSCs a promising alternative to other tissue engineering techniques, which use adult stem cells derived from the bone marrow or fat tissue.
One challenge the researchers sought to overcome was developing a uniformly differentiated population of chondrocytes, cells that produce collagen and maintain cartilage, while culling other types of cells that the powerful iPSCs could form.
Researchers induced chondrocyte differentiation in iPSCs derived from adult mouse fibroblasts by treating cultures with a growth medium.
They also tailored the cells to express green fluorescent protein only when the cells successfully became chondrocytes.
As the iPSCs differentiated, the chondrocyte cells that glowed with the green fluorescent protein were easily identified and sorted from the undesired cells.