Bisphosphonate effects on Nothobranchius furzeri

Alendronate, which belongs to the group of nitrogen containing bisphosphonates (aminobisphosphonates), is known to effectively inhibit osteoclastic bone resorption and is used in the treatment of osteoporosis. Previous observational studies have found a beneficial effect of nitrogen containing bisphosphonates on mortality; nevertheless, the mechanisms of mortality reduction by this type of bisphosphonates are largely unexplored. At the present moment, only one randomized controlled clinical trial, that has observed mortality as a secondary endpoint, exists. Due to this, the mortality lowering effect need to be investigated in more detail. To facilitate this, the turquoise killifish, Nothobranchius furzeri, was selected for this study. Nothobranchius furzeri is an established model of accelerated aging that has an extremely short life cycle (3-7 months) and therefore is ideally suited as a model for our study. In order to be able to study the effect of alendronate on mortality in Nothobranchius furzeri, 100 16-week-old female fish will be treated with alendronate and monitored for survival. In addition, further 100 untreated control fish will be observed. After the death of the fish, bones from both fish groups (treated and untreated) will be examined by micro-CT analyses, histology and histomorphometry. Furthermore, immunohistochemistry, RNA-sequencing and PCR analysis will be performed. This study can be used to determine how alendronate treatment affects the lifespan of Nothobranchius furzeri. We expect that treatment with alendronate will increase survival. Additionally, the effects of alendronate on bone remodeling, the immune system, and the cardiovascular system will be investigated. The generated results of this study will serve as a basis for investigating the mechanisms contributing to the possible mortality-lowering effects of nitrogen containing bisphosphonates. In addition, with this study, we aim to establish Nothobranchius furzeri as a future model for the study of bisphosphonate-mediated effects and research of future osteoporosis therapies.

Alendronate, which belongs to the group of nitrogen containing bisphosphonates (aminobisphosphonates), is known to effectively inhibit osteoclastic bone resorption and is furthermore considered as first line treatment of osteoporosis. Previous observational studies have found a beneficial effect of nitrogen containing bisphosphonates on mortality, but the mechanisms of mortality reduction by this type of bisphosphonates are largely unexplored. At the present moment, only one randomized controlled clinical trial, that has observed mortality as a secondary endpoint, exists. Due to this, the mortality lowering effect need to be investigated in more detail. To facilitate this, the turquoise killifish, Nothobranchius furzeri, was selected for this study. The Nothobranchius furzeri is an established model of accelerated aging that has an extremely short life cycle (3-7 months) and is therefore ideally suited as a model for our study. In order to investigate the effect of alendronate on mortality in Nothobranchius furzeri, a total of 89 16-week-old female fish were examined. Some were treated with alendronate and some remained untreated, with both groups being monitored for survival. After the fish died, bones of both groups (treated and untreated) were examined using micro-CT analysis, histology, and histomorphometry. In addition, immunohistochemistry, RNA sequencing, and PCR analyses were performed. Our study revealed that alendronate treatment had a positive effect on the lifespan of Nothobranchius furzeri, as the treated fish lived longer than the control fish. We detected a positive effect on the bone characteristics, as the treated group had more osteoblasts, which are responsible for bone formation. Using RNA sequencing, we were able to observe a reduction in ZNF703, a protein associated with breast cancer, in the treated fish. Taken together, our study showed as a primary endpoint a life-prolonging effect after alendronate treatment, which was never documented like this before in another species. These results will serve as a basis for further investigations to better understand the effect of alendronate. We were also able to further establish Nothobranchius furzeri as a model in osteoporosis research.