Cell based therapies 4 (PB)
Terms in this set (15)
for most effective maturation of tissue in vitro, different physical (+ chemical) cues may be required, e.g. O2 concentration, fluid flow, forces - can be achieved in bioreactors
What are examples of bioreactors?
-Stirred flask bioreactor
-Rotary cell culture bioreactor
Bioreactors -> Bone defect repair
-The temporomandibular joint (TMJ) =used as model in tissue engineering studies as v. difficult to generate in vitro
-combo of natural scaffold, bioreactor technology and cell biology used to successfully replicate a TMJ with cells at a physiological density
increased cell proliferation & bone matrix formation
in comparison to static
Using the Body as a Bioreactor
-Rather then replicating in vivo conditions in the lab, can just
use the body
as a bioreactor!!
-Correct environment for tissue development= chemical signalling, mechanical forces etc.
Insert scaffold into the host
and let body do the work
hydrogel injected between periosteum and tibia in rabbits to create an 'in vivo bioreactor'
Acellular strategies vs. Engineered tissues
(viruses, viroids, and prions are acellular infectious agents, meaning that they are not composed of cells)
-can be designed to release cocktails of small and macromolecular drugs and to recruit specific cells
Applications of bioreactors - BRONCHIAL repair
-immediate restoration of functional aiway
-no donor antibodies and no immunosuppressive drugs
The Challenge of Complexity
-for all types of scaffold there are hundreds of examples of seeding cell type x on biomaterial y to give tissue z
-however, tissues are extremely complex
3D, vascular network, nervous connections
e.g. the heart, liver
--> The challenge of complexity -VASCULARISATION (1)
:( Problem: cells need to be within 200 micrometres of a blood vessel to survive in the body
:( tissue engineered constructs
need capillaries which integrate
with the pt
Solutions to the VASCULARISATION (1) challenge
1) Seed scaffold with
- randomly or using pre-formed channels
Build scaffold around
vascular bed ex vivo
--> The challenge of complexity -VASCULARISATION (2)
in our blood contain many proteins which can help promote the formation of blood vessels - e.g.
PDGF, VEGF, FGF-2, EDG
:( Also have
endothelial progenitor cells
in our blood which can form blood vessels when stimulated e.g.
Endothelial Colony Forming Cells (ECFCs)
(Potential) Solutions to the VASCULARISATION (2) challenge
platelet lysate and ECFCs
- offers ready made, vessel-containing scaffold for engineering many tissue types
in the gel will stimulate the pt's existing vessels to integrate
All materials derived from pt
- so no rejection or disease transmission problems
What is 3D bioprinting used for?
=attempts to address 3D organisation of cells
What are the challenges with 3D bioprinting?
:( cell density
:( mechanical integrity
What are 5 body parts you can make with 3D printers?
Vascular networks via 3D printing
1) print a 3D carbohydrate-glass latice
2) encapsulate lattice and living cells in ECM
3) dissolve lattice in cell media
4) living cells in monolithic ECM with perfusable vascular architecture