Lcture 1 Flashcards
What is normal homeostasis?
The balance of proliferation and apoptosis
When there is an injury to a tissue
What are the four stages of wound healing?
- Hemostasis
2.inflmmaory - Proliferating
- Remodelling
What happens during hemstasis?
Blood clot
What happens duringinflammatory?
A sca is formed
There are fibroblasts and macrophages present
What happens during proliferation?
Fibroblasts begin to proliferate and subcutaneous fat is present
What happens during remodelling?
Freshly healed epidermis
Freshly healed dermis
Tissu repair drama?
Proliferation and migration of different cells: the actors
Laying down of extracellular matrix: the setting
Growth factors: means of communication
Remoddlelling of collagen to form scar
How does receptor mediated cell signalling work?
Ligand from the sending cell binds to receptor and target cell and initiates a response
What cells are labile?
Stem cells
Skin epithelium
Salivary gland
GI epithelium
What cells are stable? Quiescent
Fibroblasts
Endothelial cells
Smooth muscle cells
Lymphocytes
What cells are permanent? Nondividing
Cardiac muscle cells
Skeletal muscle cells
Growth factors- specialised proteins act as?
Ligands
What does the transforming growth factor beta do?
The most critical in tissue repair. They proliferate and stimulate fibroblasts to secrete collagen. Repair fibrous connective tissue at the injury site.
What does PDGF do? Platelet driven growth factor
It calls neutrophils, macrophages and fibroblasts to the injury site. Aids in wound contraction
What do FGF do? Fibroblast growth factor
Initiate the migration of epithelial cells, aid in wound contraction and stimulates angiogenesis (forming new blood vessels)
What does vascular endothelial growth factor do?VEGFF
Angiogenesis
What does epithelial growth factor and hepatocyte growth factor do?
Stimulate epithelial and hepatocyte proliferation and enhances epithelial cell migration
What is present in the interstitial matrix?
Collagen,elastin, fibronectin, proteoglycans and hyaluronan
What is present in the basement membrane?
Nonfibrillar collagen, laminin and proteoglycans
What is the extra cellular matrix made up of?
Interstitial matrix and the basement membrane
What is the structural properties of the ECM
Firmness to bone (collagen and elastin)
What is the resilient properties of the ECM?
Imparting resilience to soft tissues (proteoglycans and hyaluronan)
What are the adhesive properties of the ECM?
Stores and presents growth factors, such as scaffolds, facilitates cell growth (integrins, fibronectins and laminin)
What is the tissue engineering classic approach?
…
Are stem cells easily obtained in large number?
Yes
Are stem cells safe to implant?
Yes
Are stem cells easy to differentiate into the cells needed?
Yes
What do blastocysts change into?
Inner cell mass then embryonic stem cells
What do fibroblasts from the skin Change into?
Defined factors and then induced pluripotent stem cells
What do muscle stem cells change into?
Adult stem cells
What do mesenchymal cells differentiate into?
Osteoblasts (bone)
Chondrocyte(cartilage)
Adipocyte(fat)
what do stem cells undergo?
differentiation and renewal
dental stem cells undergo multidifferentiation into what?
odontoblast
osteoblast
chondrocyte
adipocyte
myocyte
endothelial cells neural cells
what are the sources in which we can get dental stem cells?
PDL
apical papilla
dental follicle
dental pulp
when should the tooth be placed into the transport medium?
immediately after exodontia or exfoliation
after transport medium what happens to the tooth
seperation of dental tissue containing stem cells
next stage?
explant or enzymatic and or mechanical dissociation of dental tissue
after apical papilla in exlpant?
dental stem cells are in culture?
what is the ideal scaffold for dental tissue engineering?
extracellular matrix
what is the tissue engineering purpose?
natural and synthetic
natural polymer?
biocomaptible
degradable
nontoxic but risk of transmitting pathogens
immune response
what are the natural materials?
proteins
polysaccharides
nucleic acid
collagen?
speical interest
mechanically weak
rapid degradation
synthetic scaffolds?
PLA
PGA
PCL
nontoxic
biocompatible
immune response
acidic
what are the copolymers
PEG
PBT
PU
more useful?
see the powerpoint for the flowchart on DPSCs differentiating into various specialised cells because wtf is that
what is PRF?
platelet rich fibrin which is a regenrative additive currently used in dentistry
what is platelet rich fibrin a matrix of?
autologous fibrin and concentrated suspension of growth factors
what does PRF act as?
bioactive surgical additives applied locally to induce wound healing
what is PRF used in?
oral and maxillofacial surgery, enhancing stem cells for bone regenration in the host bone and bone graft
what does PRF possibly be used for?
as a resorbable membrane for guided bone regeneration
what are the feature of PRF?
low volume
less handling time
injury to the blood collection site
see powerpoint for the flowchart on current approaches in dentine pulp regenration
what are the current pulp regenration strategies using DPSCs?
functional regeneration with neurovascularization..
DPSCs/SHED/sheets/aggregates/pellets
DPSCs/SHED organic/synthetic scaffolds
DPSCs/SHED pretreated/combined with growth factors
DPSCs/SHED together with endothelial cells
bone regeneration approach using DPSCs stages
- dental pulp is extracted from human theet
- DPSCs are expanded under specific condition
- DPSCs are seeded on collagen scaffold
- scaffolds with DPSCs are impalnted in animal models
- after 30-60 days bone tissue is recovered from animals
what is the approach for whole tooth regeneration?
3D cell manipulation where epithelial cells and mesenchymal cells form a bioengineered tooth germ whic is tranplanted to the bone and erupts
what is the approach for generation of a bioengineered tooth unit
tooth unit will include tooth PDL alveolar bone and is placed into the bone and becomes engrafted
what can be used to treat black triangles
TEP injection which regenrates the dental papilla
features of young stem cells
highly proliferative and huge regenrative potential