Ch13 pt 3: Response Bone Homeostasis

The Impact of the Host Inmunoinflammatory

Bone Remodeling

(2 Types)

Osteoclasts?

• Are multi? 

• Activation meditated by cell surface receptor activator of? 

Osteoclasts Cells

• Bone-resorbing cell

• Are multinucleated

• Activation mediated by cell- surface receptor activator of nuclear factor kappa-β (RANK)

Bone Remodeling

Osteoblasts

• Synthesize (2)

• Involved in? 

Osteoblasts are special bone- forming cells

• Synthesize collagen and other bone proteins

• Involved in mineralization of bone matrix

Regulation of the Bone Remodeling Cycle

• Protein catalyst expressed on?

• Osteoclastic ?

Resorption occurs when RANKL binds to RANK :

• Stimulates precursor cells to?

Receptor activator of nuclear factor kappa-b (kB) ligand (RANKL)

• Protein catalyst expressed on osteoblast membrane

• Osteoclastic differentiation factor 

Resorption occurs when RANKL binds to RANK 

• Stimulates precursor cells to differentiate into osteoclasts

Regulation of the Bone Remodeling Cycle

1. Osteoprotegerin= Protein signaling molecule produced?

2. Protects bone from excessive resorption by (2)?

Osteoprotegerin (OPG) 

1. Protein signaling molecule produced by osteoblasts

2. Protects bone from excessive resorption by

• Binding to RANKL

• Blocking binding with RANK

Mechanism of Bone Metabolism

1. Homeostatic condition occurs when?

• RANKL and OPG in balance?

2. Bone resorption occurs when?

• OPG levels decrease with (2)

1. Homeostatic condition occurs

• When body maintains stable level of alveolar bone 

• RANKL and OPG in = Balance in periodontal tissues

2. Bone resorption occurs

• when osteoblasts stimulated by RANKL to resorb alveolar bone 

OPG levels decrease with

• Periodontal inflammation

• Stimulating resorption

Biochemical Mediators

Examples of molecules that stimulate resorption:

• RANKL

• Stimulatory cytokines (IL-1β, TNF-α, IL-6, IL-11, IL-17)

• Prostaglandin E2 (PGE2)

Examples of molecules that inhibit resorption:

• OPG

• Inhibitory cytokines (IL-4, IL-10, IL-12, IL-13, IFN-γ)

The Link Between Periodontitis and RANKL-Mediated Bone Resorption

In periodontal disease,

• Invades?

• Trigger release of ?

• Affects the?

In periodontal disease,

• Invading pathogens

• Trigger release of PROinflammatory cytokines

• Significantly affect bone remodeling process

The Link Between Periodontitis and RANKL-Mediated Bone Resorption

1. Proinflammatory mediators protect host from? 

• Attack by Stimulate cells (4)? 

2. RANKL activates? 

 3. If unabated

• Host inflammatory response leads to? 

1. Proinflammatory mediators protect host from microbial attack

BY Stimulate:  

1. Osteoblasts

2. Fibroblasts

3. T-cells

4. B-cells to produce RANKL

2. RANKL

• activates osteoclasts.

3. If unabated

• host inflammatory response leads to irreversible destruction of alveolar bone