Endocrine Abstracts

Osteoporosis is an emerging medical and socioeconomic problem leading to fragility fractures, loss of mobility, chronic pain and cost to the individual and society. Diagnosis is often established only after fracture, although modern techniques exist to make the diagnosis early on where specific therapy is possible. Apart from calcium and vitamin D supplementation and lifestyle counseling, bisphosphonates have become the mainstay of therapy. However, long-term adherence with bisphosphonates is poor and some complications may occur with prolonged use.

The last decade have provided key insights into bone cell biology. Deciphering the regulation of osteoclast differentiation, fusion, activation and resorption led to a comprehensive understanding of osteoclast function and identified potential targets for intervention, including RANK ligand and cathepsin K. Thus, novel molecules such as denosumab, an antibody that inhibits RANK ligand, or odanacatib, a cathepsin K inhibitor have been approved or are in advanced phase 3 studies. Their antiresorptive mode of action differs from that of bisphosphonates and may offer several advantages. With regards to osteoblast biology, characterization of the Wnt signaling pathway provided novel translational prospects to improve local or systemic bone regeneration. More recently, the osteocyte has emerged as a cellular mastermind that senses mechanical strain and guides bone remodeling. The approach to block the endogenous Wnt inhibitor sclerostin with antibodies has emerged as a novel bone-anabolic therapy that is currently evaluated. In conclusion, greater awareness, better prediction models, and novel therapies may change the way of osteoporosis therapy in the future.

Question 1: Which compound is NOT an anti-resorptive osteoporosis drug:

i) Denosumab, an antibody against RANK ligand.

ii) Teriparatide, a PTH analogue.

iii) Zoledronic acid.

iv) Odanacatib, a cathepsin K inhibitor.

v) Raloxifene, a selective estrogen receptor modulator.

Answer 2.

Question 2: Which cells are most common in bone and act as mechanosensors?

i) Osteoblasts.

ii) Osteo-macrophages.

iii) Synovial cells.

iv) Osteoblasts

v) Osteocytes.

Answer 5.