Blast/Clast

Case Relevance

Patient was experiencing reoccurring fractures in the lumbar spine and was eventually diagnosed with osteoporosis. Osteoclasts and Osteoblasts function are fundamental in understanding this disease.

• ALP

• Type 1 collagen

• RANKL

• OPS (Osteoprotegrin)

• M-CSF

Osteoblasts

• Fusion of monocyte and macrophage

• Secrete H+ and Collagenase

• Homeostasis of osteoclasts and osteoblasts

• Release TGF-Beta embedded in bone

​Osteoclasts

​Increased bone formation

• ​Low PTH- Increased Osteoclast apoptosis

• Mechanical stress

• Vitamin D- stimulates osteoblasts

• Bisphosphonates- inhibit osteoclasts

• Low Estrogen-no inhibition of osteoblast apoptosis. No apoptosis of osteoclasts.

• High PTH-stimulate osteoclasts

• Glucocorticoids-prolong osteoclast lifespan

​

​Increased bone resorption

​References

Office of the Surgeon General (US). Bone Health and Osteoporosis: A Report of the Surgeon General. Rockville (MD): Office of the Surgeon General (US); 2004. 2, The Basics of Bone in Health and Disease. Available from: https://www.ncbi.nlm.nih.gov/books/NBK45504/#