Regenerative Medicine Flashcards
What is meant by regenerative?
-Tissue injury
-Tissue repair = remodelling replaced damaged tissue forming inferior tissue (scar)
-Tissue regeneration = remodelling restores native tissue - NO scar
What is regenerative medicine?
-Regenerating extensively injured, aging, diseased tissues/organs
-Aim = help body to heal itself
-Develop cell therapies, natural & synthetic bio materials & artificial organs
What do bones & liver have in common?
Both are only organs that can repair - so look histologically same - is equally as strong (so long as insult of injury is stopped)
—> other organs heal by scar formation (not histologically same)
What is special about bone repair?
It tries to repair itself by forming new bone
Why do fractures unite?
Because the bone is broken
What is bone composed of?
What are the 2 types of bone?
-Cortical/compact/lamellar - v. hard (like block or chocolate - is shaft of bone
-Cancellous/spongy/woven - has holes in (like aero chocolate) = at ends of bones - is easier to break
What 2 things are needed for bone to heal?
-Adequate blood supply
-Adequate mechanical stability - stabilise the joint whilst body heals it, can have surgery to stabilise - but can damage blood supply
What is the blood supply to diaphyseal bone?
*Nutrient artery
Intramedullary
Supplies inner 2/3rd of cortex
*Metaphyseal vessels
Rich supply from soft tissue
*Periosteal vessels
Supplies outer 1/3rd
What are the 2 mechanisms of bone healing - state them?
-Direct/primary bone healing
-Indirect/secondary bone healing
Describe direct/primary bone healing.
-NO motion at the fracture site –> use plate to fix ends of bones together
-Rigid internal fixation
-Osteoblast form - cut cones across fracture site
-Osteoblasts lay lamellar bone down behind
-Osteons form late
-NO callus formation
-SLOW process
Reestablishment of cortex without formation of a callus - it occurs if fracture is adequately “fixed” through reduction, immobilization & rehabilitation
Describe indirect/secondary bone healing.
-Motion at the fracture site –> ends of bones not fixed rigidly - motion at bone ends = pain & discomfort - get inflammatory cascade
-Callus formation = what stabilises the bone
-Unstable
-Direct healing between cortices
Occurs through formation of a callus & subsequent remodelling
Consists of endochondral & intramembranous bone healing
It does not require anatomical reduction or rigidly stable conditions
Soft callus (a type of soft bone) replaces blood clot that formed in inflammatory stage -> callus holds bone together, but isn’t strong enough for body part to be used
Over next few weeks - soft callus becomes harder
Describe the healing cascade within indirect/secondary bone healing.
*Inflammation 0 – 5 days
-Haematoma = blood clot
-Necrotic material
-Phagocytosis
*Repair: 5 – 42 days
-Granulation tissue
-Acid environment
-Periosteum – osteogenic cells
-Cortical osteoclasis
*Late repair:
-Fibrous tissue replaced by cartilage
-Endochondral ossification
-Periosteal healing » membranous ossification
*Regeneration & remodelling
-Replacement of callus (woven bone with lamellar bone)
-Continued osteoclasis
-Mechanical strain
Soft callus (a type of soft bone) replaces blood clot that formed in inflammatory stage -> callus holds bone together, but isn’t strong enough for body part to be used
Over next few weeks - soft callus becomes harder
What is the future for treating osteoarthritis in knees?
What is articular cartilage made up of?
-65-80% water = allows deformation
-Type 2 collagen = tensile strength
-Proteoglycans = compressive strength
-Chondrocytes = protein synthesis
-Matrix components = adhesives and
