Researchers at the Swiss Federal Technology Institute of Lausanne and the startup biotechnology company Flowbone have developed an injectable hydrogel that may revolutionize osteoporosis treatment by rapidly strengthening fragile bones. This hydrogel—composed of hyaluronic acid and hydroxyapatite nanoparticles—replicates the natural composition of bones and delivers rapid and localized reinforcement that leads to a threefold increase in bone density within weeks.
A Breakthrough in Osteoporosis Treatment: Scientists Develop Injectable Hydrogel That Rapidly Increases Bone Density and Strengthens Bones
Background
Osteoporosis, a condition that weakens bones and increases the risk of fractures, affects millions worldwide, particularly postmenopausal women. Current treatments can slow bone loss or promote bone formation but often take months or even years to show significant effects. This leaves patients vulnerable to life-threatening fractures in the meantime.
Researchers V. A. Stadelmann, E. Gerossier, U. Kettenberger, and D. P. Pioletti examined how combining systemic and local or targeted osteoporosis treatments affects bone microstructure in ovariectomized rats. These rats served as a model for postmenopausal osteoporosis. The goal was to see whether injectable biomaterials could increase bone density and enhance bone structure when used alongside systemic drugs.
The rats were grouped into three and given either no systemic treatment, the bisphosphonate drug Alendronate used for slowing bone loss, or the Parathyroid hormone used for stimulating bone formation. All three groups were also injected with either a hydrogel solution or a hydrogel solution with another bisphosphonate and antiresorptive drug Zoledronate.
Results
• Local Hydrogel Effect: Rats that were given no systemic treatment but injected with either a hydrogel solution or a hydrogel solution combined with Zoledronate demonstrated an increase in bone mass at the injection site within 2 weeks. These showed rapidly enhanced local bone density. However, bone resorption or breakdown resumed over time.
• Systemic Drug Effect: Those that were given Alendronate had extended bone mass gains and those given with Parathyroid hormone benefitted the most from the combination of a hydrogel solution and Zoledronate. Combining two bisphosphonates seemed to provide no extra benefit as seen when Alendronate was used together with Zoledronate.
Implications
Local injection of a hydrogel solution made of hyaluronic acid and hydroxyapatite nanoparticles and another solution in combination with Zoledronate can effectively increase bone density at the injection site. However, because the effect is localized and bone resorption or breakdown resumed over time, the hydrogel alone is not an effective treatment for osteoporosis.
Combining these local treatments with systemic drug administration can have additive effects. This can potentially lead to better fracture prevention in high-risk patients. The effects of the hydrogel injection are specifically prolonged and maintained by drugs aimed at arresting bone loss. Results have also suggested that a personalized approach may be key in osteoporosis treatment. This involves matching patients to the best local-systemic drug combination.
Researchers aim to secure regulatory approval and start clinical trials to further test the merits of their hydrogel solution. Flowbone is targeting to commercialize this hydrogen solution in the near future. Nevertheless, once successful, it could redefine osteoporosis treatment by offering a faster and more targeted way to strengthen bones and prevent fractures.
FURTHER READING AND REFERENCE
- Stadelmann, V. A., Gerossier, E., Kettenberger, U., and Pioletti, D. P. 2025. “Combining Systemic and Local Osteoporosis Treatments: A Longitudinal In Vivo MicroCT Study in Ovariectomized Rats. In Bone. 192: 117373. Elsevier BV. DOI: 1016/j.bone.2024.117373