After injury to most tissues, the body has to reestablish a healthy blood supply in order to recover. But when the goal is to repair articular cartilage—the layers cushioning the knee joint, for example—scientists must get creative, since cartilage is one of the few tissues naturally free of blood vessels.
In the June 14 online edition of Tissue Engineering, researchers describe a new implantable biologic device that in laboratory tests can express endostatin, a blood supply–regulating protein, and also develop into cartilage. Because endostatin inhibits new blood vessel growth, it is also undergoing evaluation as a means of treating cancerous tumors, which rely for growth on an expanding blood vessel network. According to the paper’s lead author, Lily Jeng, a graduate student in MIT’s Department of Biological Engineering, injury or surgery in the articular cartilage of joints can induce a new blood supply. Though initially beneficial for healing, the new vessels can ultimately interfere with the conversion of new tissue into cartilage.
The researchers—including Bjorn Olsen, dean for research and professor of developmental biology at HSDM and the Hersey professor of cell biology at HMS, and Myron Spector, an HMS professor of orthopedic surgery (biomaterials) at Brigham and Women’s Hospital who directs the Tissue Engineering Laboratories at the VA Boston Healthcare System—discovered that endostatin might be applicable to cartilage repair. The team created an implantable polymer scaffold that expressed this blood vessel growth inhibitor and developed into cartilage over the course of several weeks.
“The innovation here is the simultaneous use of the construct for tissue regeneration and as a delivery vehicle for a regulatory molecule,” said Spector. Looking forward, the researchers want to see whether the endostatin-producing structure can improve cartilage regeneration in living organisms.
The device might improve cartilage regeneration in the knee following injury, Spector said. A construct of this type could also be modified by using other cell types and proteins for applications as wide-ranging as spinal cord regeneration, traumatic brain injury repair and bone tissue engineering.
For more information, students may contact Myron Spector at mspector@rics.bwh.harvard.edu.
Conflict Disclosure: The authors declare no conflicts of interest.
Funding Sources: The U.S. Department of Veterans Affairs, the Department of Defense and the National Science Foundation; the authors are solely responsible for the content of this work.
