[Novel anti-osteoporotic drugs on the horizon]
A Knauerhase1, H S Willenberg2
1Zentrum für Innere Medizin, Abteilung für Gastroenterologie/Endokrinologie, Sektion Endokrinologie/Stoffwechselerkrankungen, Universitätsmedizin Rostock, E.-Heydemann-Str. 6, 18055, Rostock, Deutschland. andreas.knauerhase@uni-rostock.de.
Abstract:
In recent years the great progress in knowledge on bone cell biology has allowed identification of molecular structures that can be targeted with pinpoint precision (druggable targets). Osteoclasts are regulated via the RANK-RANK-ligand (RANKL) signaling pathway and osteoblasts via the Wnt signaling pathway, both of which can be influenced for therapeutic measures. As a result the number of (functional) osteoclasts can be decreased or the genesis of osteoblasts can be increased and bone resorption is inhibited or bone formation is enhanced, respectively. Osteoclasts degrade collagen through cathepsin K and inactivation of this enzyme stabilizes the bone matrix; however, as osteoclasts are still able to maintain a stimulatory cross-talk with osteoblasts, formation of new bone will not be reduced. Parathyroid hormone-related protein plays a role in endochondral ossification and a synthetic analogue of this protein may have potent bone anabolic activity; however, the use of such new and highly efficient therapeutic principles comes with new questions and uncertainties on the sequence of therapies, duration of therapy, long-term side effects, undesired activation of metabolic pathways and effectiveness in comparison to other strategies of fracture prevention.
Insights
New bone cell biology insights reveal targeted therapies. Targeting osteoclast and osteoblast pathways, like RANK-RANK-ligand (RANKL) and Wnt, can inhibit bone resorption or enhance bone formation for fracture prevention.
Area of Science:
- Bone cell biology
- Molecular targets in bone metabolism
Background:
- Advances in bone cell biology have identified druggable targets for therapeutic intervention.
- Osteoclast and osteoblast activity is regulated by specific signaling pathways, including RANK-RANK-ligand (RANKL) and Wnt.
Purpose of the Study:
- To explore therapeutic strategies targeting bone cell biology for enhanced bone formation and inhibited resorption.
- To discuss the implications of novel therapeutic principles in bone anabolic activity and fracture prevention.
Main Methods:
- Targeting the RANK-RANK-ligand (RANKL) pathway to decrease osteoclast number and function.
- Targeting the Wnt signaling pathway to increase osteoblast genesis.
- Investigating cathepsin K inhibition to stabilize bone matrix.
- Exploring synthetic analogues of parathyroid hormone-related protein for bone anabolic activity.
Main Results:
- Modulating RANKL and Wnt pathways can respectively decrease osteoclasts or increase osteoblasts, leading to inhibited resorption or enhanced formation.
- Inactivating cathepsin K stabilizes bone matrix while preserving osteoblast cross-talk, potentially avoiding reduced new bone formation.
- Synthetic parathyroid hormone-related protein analogues show potential for potent bone anabolic activity.
Conclusions:
- Targeted therapies offer promising approaches to modulate bone resorption and formation.
- New therapeutic principles necessitate careful consideration of treatment sequencing, duration, long-term effects, and comparative effectiveness for fracture prevention.
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