Smart Hydrogel Draws Special Repair Cells to Fix Broken Cartilage


The confocal image shows chondrogenic progenitor cells migrating into the cartilage injury site in response to the stromal cell-derived factor 1(SDF1) contained in the hydrogel.

Very sadly for many of us, cartilage is a tissue not known to naturally repair itself. That’s an important reason why so many professional sporting careers end abruptly and why knee replacements as common as they are. Researchers at the University of Iowa may help change that thanks to a new way of activating a healing mechanism with the help of a bioactive hydrogel. The researchers discovered precursor cells existing within cartilage that mature into actual cartilage tissue and identified a molecular signal that attracts these cells to migrate towards it. They seeded this compound, called stromal cell-derived factor 1 (SDF1), within a special hydrogel and injected it into injured cartilage. Amazingly, the hydrogel worked as intended, drawing the chondrogenic progenitor cells towards itself and filling the openings within the cartilage with new tissue.

The new tissue is not as strong as healthy cartilage, but the researchers believe that by adding a bit of stress training to it might toughen it up. The research is still in a laboratory stage and there’s a long way to go before it can be developed into a clinical therapy, but things are looking promising.

Some details from the study abstract in Arthritis & Rheumatology:

Use of rhSDF-1α dramatically improved CPC recruitment to the chondral defects at 12 days. After 6 weeks under chondrogenic conditions, cell morphology, proteoglycan density, and the ultrastructure of the repair tissue were all similar to that found in native cartilage. Compared with empty controls, neocartilage generated in rhSDF-1α–containing defects showed significantly greater interfacial strength, and acquired mechanical properties comparable to those of native cartilage.

This study showed that stimulating local CPC recruitment prior to treatment with chondrogenic factors significantly improves the biochemical and mechanical properties of the cartilage tissue formed in chondral defects. This simple approach may be implemented in vivo as a one-step procedure by staging the release of chemokine and chondrogenic factors from within the hydrogel, which can be achieved using smart drug-delivery systems.

Study in Arthritis & Rheumatology: Use of Recombinant Human Stromal Cell–Derived Factor 1α–Loaded Fibrin/Hyaluronic Acid Hydrogel Networks to Achieve Functional Repair of Full-Thickness Bovine Articular Cartilage Via Homing of Chondrogenic Progenitor Cells…

Source: University of Iowa…