An orthopedics research team from the University of Iowa (UI) is developing an injectable, bioactive hydrogel, designed to repair cartilage damaged from knee injuries. Their hope is that this new product will result in a minimally invasive, practical, and inexpensive solution for repairing cartilage and preventing osteoporosis and total knee replacement, according to a news release from University of Iowa.

Yin Yu, a graduate student in the lab of James Martin, PhD, UI assistant professor of orthopedics and rehabilitation, is the first author of a study about the product, which is featured on the cover of the May issue of the journal Arthritis and Rheumatology, the release notes.

Per the release, Martin’s team previously identified precursor cells within normal cartilage that can mature into new cartilage tissue. They also identified molecular signaling factors that attract these precursor cells, known as chondrogenic progenitor cells (CPC), out of the surrounding healthy tissue into the damaged area and cause them to develop into new, normal cartilage. One of the signals is called stromal cell-derived factor 1 (SDF1), and it acts like a homing beacon for the precursor cells.

Using an experimental model of cartilage injury, Yu loaded the hydrogel with SDF1 and injected it into holes punched into an experimental model of cartilage injury, the release continues. The precursor cells migrated toward the SDF1 signal and filled in the injury site. After subsequent application of a growth factor, the cells matured into normal cartilage that repaired the injury.

The new tissue is not as mechanically strong as normal cartilage, the release explains. However, Yu and Martin believe that mechanical loading—the type of stress that is exerted during physical therapy and exercise—might improve the mechanical properties.

To translate this approach into a therapy that can eventually be used in people, the release notes, Yu and Martin have teamed with UI pharmacy professor Aliasger Salem, PhD, to include the growth factor in such a way that there is a stepwise release of SDF1 followed by the growth factor. They are testing two technologies—nano-size plasmids carrying genetic instructions for the growth factor or microspheres loaded with the substance—to incorporate the growth factor into the gel.

Their long-term goal is to commercialize the gel as a human therapy, the release says. Yu is participating in UI Venture School, where he and several colleagues developed a business plan for the product.

Yu and Martin plan to start animal trials within a year, the release concludes. If their results are good, they hope to be ready to start human trials in about 5 years.

[Sources: University of Iowa, Science Daily]