Term
| reasons for tissue engineering |
|
Definition
transplantation crisis, shortage of donor organs and tissues available
transplant rejection |
|
|
Term
| what are the four basic tissue types |
|
Definition
| muscle tissue, nerve tissue, epithelial tissue, and connective tissue |
|
|
Term
| muscle tissue types and functions |
|
Definition
skeletal (voluntary), smooth (involuntary), cardiac (only found in heart, involuntary)
contracts for movement and support |
|
|
Term
| nerve tissue: types and functions |
|
Definition
| brain, spinal cord, nerves, gives signals to muscles, informs us of environmental conditions |
|
|
Term
| epithelial tissue: types and functions |
|
Definition
| lines our organs such as stomach lining, skin (epidermis) (endothelial - blood vessels) |
|
|
Term
| Three Essential Components of Tissue |
|
Definition
| cells, extracellular matrix, soluble factors |
|
|
Term
|
Definition
| growth factors, hormones, cytokines, soluble gases |
|
|
Term
| cellular tissue engineering components |
|
Definition
| cells, scaffolds, extracellular signals = biological substitute |
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|
Term
| example of natural scaffold |
|
Definition
|
|
Term
| a method to promote blood supply structure |
|
Definition
|
|
Term
| what prevents blood from coagulating in blood vessels? |
|
Definition
|
|
Term
| why don't scaffolds work well in vascular tissue engineering? |
|
Definition
| smooth muscle is more easily growing than endothelial cells, scaffold gets covered with smooth muscle, and blood coagulates at the site |
|
|
Term
| can neurons divide/proliferate? |
|
Definition
|
|
Term
|
Definition
| make the environment conducive to regeneration |
|
|
Term
|
Definition
epidermis - top layer
dermis
hypodermis |
|
|
Term
|
Definition
| top layer, not much ECM, densely packed |
|
|
Term
|
Definition
|
|
Term
|
Definition
| cells that create rapid growth, often scar tissue |
|
|
Term
| negative effects of fibroblasts in the heart |
|
Definition
| heart attack, tissue dies forever, fibroblasts create scar tissue, difficult to contract |
|
|
Term
| how do you know if you damaged the dermis? |
|
Definition
|
|
Term
| formation of ECM - dynamic or static? |
|
Definition
|
|
Term
| how do cells know to attach to a scaffold? |
|
Definition
| growth factors, cells will follow a growth factor gradient |
|
|
Term
| our ECM is hydrophillic, so why don't we dissolve? |
|
Definition
| strands are tangled and interwoven, no opportunity to dissolve |
|
|
Term
| connective tissue: types and functions |
|
Definition
| connects, supports, and protects other tissues, ligament, bone, tendon, blood, hair |
|
|
Term
| tissue engineering process |
|
Definition
cell sourcing
cell expansion and manipulation
mechanical and molecular signalling
cell seeding and ECM expression
implantation of construct |
|
|
Term
| what was with that vacanti mouse? |
|
Definition
| they grew a human ear on the mouse's back |
|
|
Term
| why wouldn't the ear from the vacanti mouse function if implanted onto a human? |
|
Definition
mouse epidermis would cause rejection -- xenograph (across species)
cartilage cells were from a cow - very different from human cartilage |
|
|
Term
|
Definition
| multiply constantly through life, high rate of death |
|
|
Term
| examples of renewing, labile cells |
|
Definition
| skin, intestinal epithelium, bone marrow |
|
|
Term
|
Definition
| low rate of death and replication, divide following stimulation |
|
|
Term
|
Definition
| lack any capacity to divide |
|
|
Term
|
Definition
| new keratinocytes divide here and as they reproduce and make a structural protein called keratin, they are pushed upward until they die and form the outer skin layer |
|
|
Term
| Anatomy of the small intestine |
|
Definition
crypt progenitors
enterocytes
goblet cells
villi
epithelial sheet |
|
|
Term
| crypt progenitors function |
|
Definition
| cells at bottom of wells in submucosa, divide every 12-16 hours, 200 cells per crypt every day |
|
|
Term
|
Definition
|
|
Term
|
Definition
| provide a mucus lining in the small intestine - keeps the intestine from digesting itself |
|
|
Term
| how long do cells live in the intestine? |
|
Definition
| cells reach the top of the villus and shed off in 5 days |
|
|
Term
|
Definition
in the small intestion - at the crypt bottoms
secrete antimicrobial peptides and enzymes |
|
|
Term
|
Definition
| in marrow cavity of bone, synthesizes blood |
|
|
Term
|
Definition
| blood cells - plasma life of about 120 days |
|
|
Term
| examples of expanding (stable) cells |
|
Definition
| endothelium, fibroblasts, liver cells, smooth muscle cells |
|
|
Term
| examples of renewing (labile) cells |
|
Definition
| skin, intestinal epithelium, bone marrow |
|
|
Term
| examples of static (permanent) cells |
|
Definition
| heart muscle cells, neurons |
|
|
Term
|
Definition
autologous
allogeneic
xenogeneic |
|
|
Term
|
Definition
from the patient
differentiated cells of same or other tissue type
stem cells (e.g. from bone marrow, fat of other tissue, or saved from umbilical cord |
|
|
Term
|
Definition
from other human sources
differentiated cells of same or other tissue type
fetal stem cells
embryonic stem cells |
|
|
Term
|
Definition
from a different species
differentiated cells of same or other tissue type
fetal stem cells
embryonic stem cells |
|
|
Term
| autologous cells - pros and cons |
|
Definition
pros: immunologically acceptable
cons: not readily available, donor site morbidity |
|
|
Term
| allogeneic cells - pros and cons |
|
Definition
pros: can be readily available
cons: not always immunologically acceptable |
|
|
Term
| xenogeneic cells - pros and cons |
|
Definition
| cons: requires engineering immunological tolerance, potential animal virus transmission |
|
|
Term
|
Definition
self renewal, reproduce itself
differentiation, differentiate into functional phenotypes |
|
|
Term
| symmetric division of stem cells |
|
Definition
| one stem cell divides into two stem cells |
|
|
Term
| asymmetric division of stem cells |
|
Definition
| one stem cell divides into one stem cell and one progenitor cell |
|
|
Term
|
Definition
| can divide many times, can divide 2^30 |
|
|
Term
| is stem cell division rate high or low? |
|
Definition
| low - progenitor cells do most of the division |
|
|
Term
| what is the ratio of stem cells to all cells? |
|
Definition
| 1 in 10 to 15 thousand cells |
|
|
Term
| what do you use to expand cells? |
|
Definition
| culture flask - flat bottom |
|
|
Term
|
Definition
when cells come in contact with each other, they stop proliferating
this is generaly defective in cancer cells |
|
|
Term
|
Definition
| glycoprotein in the ECM - binds to integrin proteins |
|
|
Term
| how do you spur on the correct cell differentiation? |
|
Definition
| correct environment - nerve cells need electrical stimulation, bone cells need mechanical stimulation |
|
|
Term
|
Definition
| cells and scaffold structure that can be implanted into the body |
|
|
Term
|
Definition
| must be slow enough to allow tissue infiltration - if it degrades too fast, tissue will lose its structure |
|
|
Term
| cartilage cells - why should you stent it? |
|
Definition
| cells not mature enough in the first 12 weeks to counter the forces by the skin in healing - it would lose shape |
|
|
Term
| why can't you put chondrocytes (cartilage cells) in the center of a scaffold? |
|
Definition
| necrosis due to lack of nutrition |
|
|
Term
|
Definition
| cell homicide vs cell suicide, respectively |
|
|
Term
|
Definition
blood disease, not able to grow new healthy RBC - need a bone marrow transplant
generally, bone marrow injected into the blood stream directly |
|
|
Term
|
Definition
| stem cells that have the potential to become any cell type in the adult animal body, and any cells of the extra embryonic tissue (placenta and umbilical cord) |
|
|
Term
|
Definition
| the potential to differentiate to all somatic cells (but not to those of the placenta and umbilical cord which is derived from a trophoblast) |
|
|
Term
|
Definition
| stem cell that placenta and umbilical cord are differentiated from |
|
|
Term
|
Definition
| stem cells that can only differentiate into a limited number of type (ex. trophoblasts) |
|
|
Term
|
Definition
| pluripotent, derived from inner cell mass of blastocyst |
|
|
Term
| induced pluripotent stem cells |
|
Definition
| also known as iPS cells, adult cells that have been genetically programmed to an embryonic stem cell-like state |
|
|
Term
|
Definition
undifferentiated cells that are found in differentiated adult tissues
ex) bone marrow, fat,blood,brain, and spinal cord, dental pulp, liver, skeletal muscle, pancreas, epidermis, mucosa of the digestive system |
|
|
Term
|
Definition
| cord blood, amniotic fluid and placenta |
|
|
Term
| source of a totipotent stem cell |
|
Definition
| 4 cell stage of a zygote - all four totipotent - after thi step, cells are pluripotent |
|
|
Term
| source of pluripotent stem cells |
|
Definition
| inner cell mass of blastocyst |
|
|
Term
| embryonic stem cells - pros |
|
Definition
Pros: able to differentiate into all tissues in the adult body
able to replicate indefinitely while retaining their undifferentiated pluripotent state
ease of purification |
|
|
Term
| embryonic stem cells - cons |
|
Definition
risk of teratoma formation - insufficient differentiation
material of animal rejection - pathogen transmission
immunologic rejection
ethical concerns |
|
|
Term
|
Definition
encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers
undifferentiated ESCs can form teratomas after implantation |
|
|
Term
| what kind of cells can serve to make iPS cells |
|
Definition
| fibroblasts - all have the same genome - environmental factors and gene expression determine function |
|
|
Term
| true/false - it is difficult to purify adult stem cells |
|
Definition
|
|
Term
| where do trophoblasts reside? |
|
Definition
| outer layer of the blastocyst |
|
|
Term
|
Definition
| mass of cells in the inside of the blastocyst |
|
|
Term
| aintainense of pluripotency of ESCs |
|
Definition
feeder cells - fibroblasts, and serum proteins
remval of feeder cells, ESCs spontaneously differentiate into all three germ layers |
|
|
Term
|
Definition
| give rise to all blood cell types - white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes) |
|
|
Term
| mesenchymal stem cells (MSCs) |
|
Definition
| give rise to a variety of cells from mesodermal lineages including chondrocyte, osteoblasts, fibroblasts, muscle cells, tendons, adipocytes (fat cells), endothelial cells |
|
|
Term
| endothelial progenitor cells |
|
Definition
| give rise to endothelial cells |
|
|
Term
| bone marrow transplant procedure |
|
Definition
destroy diseased BM by chemotherapy and/or radiation
infusion of healthy BM into patients bloodstream
BM migrates into large cavities of the bones, begins producing normal blood cells
genetic makeups must match |
|
|
Term
| what kind of cells do you use for a bone marrow transplant? |
|
Definition
|
|
Term
|
Definition
| endoderm, ectoderm, mesoderm |
|
|
Term
| mesenchumal stem cells - properties |
|
Definition
immunoprivileged
do not express immunologically relevant cell surface markers
inhibit the proliferation of allogeneic T-cells in vitro an elicit no immune response after allogeneic or xenogeneic tranplantation
readily isolated from various sites of the human body, especially from BM and adipose tissues
expand in culture without differentiation fr 30-40 divisions |
|
|
Term
|
Definition
amniotic fluid and placenta
cord blood |
|
|
Term
| amniotic flid and placental stem cells give rive to: |
|
Definition
| hematopoietic, mesnchymal, and pluripotent cells |
|
|
Term
| cord blood stem cells give rise to: |
|
Definition
| hematopoietic, pluripotent |
|
|
Term
| fetal stem cells, pros and cons |
|
Definition
pros: ease of procurement, abundant source, higher capacity to proliferate, less immunogenic than adult stem cells, no ethical concerns
cons: limited number of cells, immunogenic |
|
|
Term
| why can't we use the stem cells we have saves in research labs now |
|
Definition
| they are garbage because we mixed crap with them and they are unusable now |
|
|
Term
| modulation of extracellular environment |
|
Definition
| growth factors, hormone, extracellular matrix components |
|
|
Term
| modulation of intracellular environment through gene transfection |
|
Definition
induce gene expression: gene transfection of transcription factors through DNA delivery
silence gene expression SiRNA delivery |
|
|
Term
| conductive signal for regulation |
|
Definition
| scaffolds for supporting host tissue growth, ECM molecules |
|
|
Term
| inductive sigal for regulation |
|
Definition
| drug delivery of soluble factors |
|
|
Term
|
Definition
mimic ECM to support:
cell adhesion
cell differentiation
cell proliferation |
|
|
Term
|
Definition
large surface area to volume ratio
macroporous
biocompatible
mechanical properties
specific 3D shape
physical guidance or patterning: topographic cues
degrade at the same rate as tissue deformation
ability to incorporate drug releasing component |
|
|
Term
|
Definition
| how many pores through a certain surface area, also how large the pores are - different sized pores for different cells |
|
|
Term
| mnufacturing porous scaffold |
|
Definition
solvent casting and particulate leaching
gas forming
freeze drying
rapid prototyping
hydrogel |
|
|
Term
|
Definition
|
|
Term
| solvent casting and particulate leaching scaffold technique |
|
Definition
salt particles, casting, vacuum dry, immerse in water
extesively used for PLLA and PLGA scaffolds
pros: pore size and porosity can be tuned by changing the particle size and the polymer/particle ratio
cons: limited thickness
cytotoxic organic solvent |
|
|
Term
| why are PLLA, PGA, and PLGA used commonly? |
|
Definition
|
|
Term
| why are PLLA PGA, and PLGA not favored by tissue engineers? |
|
Definition
| hydrophobic, not great for applications |
|
|
Term
| gas forming - scaffold technique |
|
Definition
gas creates the pores
compression molding using a heated mold
high pressure CO2 gas
gas dissolved in the polymer
closed pore morphology
pros: no organic solvents
cons: excessive heat prohibits incorporation of temperature labile materials into the polymer matrix
pores do not form an interconnected structure |
|
|
Term
| freeze drying - scaffold technique |
|
Definition
polymer dissolved in aqueous solution
rapid cooling create phase separation
solvents removal by sublimation under vacuum
pros: no organic solvents and high temperature
cons: porosity and pore size difficult to control |
|
|
Term
|
Definition
CAD design, 3D printing, three dimensional printing og scaffolds and cells
pros: predefined properties, interconnetivity
cons: slow slow slow |
|
|
Term
|
Definition
| water swollen cross-linked polymeric structures either by covalent bonds or entanglements - hydrogen bonds |
|
|
Term
| hydrogels posses a degree of flexibility very similar to natural tissue BECAUSE |
|
Definition
| of their significant water content |
|
|
Term
|
Definition
| chemical cross linking in hydrogel |
|
|
Term
|
Definition
| physical entanglement of fibers |
|
|
Term
|
Definition
|
|
Term
| how can you tell a cell is pluripotent? |
|
Definition
| it can generate a cell from each germ layer |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| use of transcription factors to do what? |
|
Definition
| maniulate gene expression |
|
|
Term
| true/false - cells will not respond to injection of transcription factors into the media |
|
Definition
|
|
Term
| how do you properly introduce transcription factors? |
|
Definition
|
|
Term
| how are scaffolds without cells advantageous? |
|
Definition
| no rejection, increased shelf life |
|
|
Term
|
Definition
| PLLA degrades slower, PGA degrade faster, PLGA is a copolymer |
|
|
Term
| disadvantages of PLLA and PGA |
|
Definition
| hydrophobic, only soluble in organic solvents |
|
|
Term
| fibrous scaffolds - technique |
|
Definition
high voltage applied to polymer solution
electrostatic repulsion counteracts the surface tension
at a critical point, a thin fibrous stream is ejected
solvent evaporation |
|
|
Term
| electrospinning - control factors |
|
Definition
| fiber diameter, porosity, and morphology can be controlled by applied voltage, viscosity, solution conductivity, and temperature |
|
|
Term
| fibrous scaffolds - traits |
|
Definition
large surface area:volume ratio
high porosity
add strength to composites
tubular (nerve, blood vessel, intestine
solid |
|
|
Term
| fibrous scaffolds, application |
|
Definition
wound repair, sutures
skin tissue engineering
cartilage tissue engineering
cardiovascular |
|
|
Term
| mechanical properties of scaffolds |
|
Definition
composed of polymers, ceramics, or composites
select material that closely resembles properties of tissue it is to replace |
|
|
Term
| soft tissue - material used |
|
Definition
| natural and synthetic polymers |
|
|
Term
| hard tissues - material used |
|
Definition
| metals, ceramics, composites |
|
|
Term
| glycosaminoglycans (GAGs) |
|
Definition
| unbranched polysaccharide chains composed of repeating disaccharid units |
|
|
Term
| glycosaminoglycan examples |
|
Definition
| hyaluronic acid, chondroitin sulfate (cartilage), dermatan sulfate, heparan sulfate, keratan sulfate |
|
|
Term
| GAGs are generally attached to _______ to form __________ |
|
Definition
| ECM proteins; proteoglycans |
|
|
Term
|
Definition
| GAG chains bound to a core protein |
|
|
Term
|
Definition
tensile strength
cell binding domain |
|
|
Term
|
Definition
| resiliency and extensibility |
|
|
Term
|
Definition
attract water
resistance to pressure |
|
|
Term
| why do GAGs attract water? |
|
Definition
| negative surface attracted positive ions, creates a concentration gradient, osmotic forces pulls water to the more concentrated areas around the GAGs |
|
|
Term
|
Definition
| attract water, keep ECM cells hydrated, store growth factors, compressive strength |
|
|
Term
| glycoproteins role in ECM |
|
Definition
| binding domain for cells and ECM molecules |
|
|
Term
| what components of the ECM promote mechanical strength? |
|
Definition
| collagen, elastin, proteoglycans |
|
|
Term
| what components of the ECM promote cell binding? |
|
Definition
| collagen and glycoproteins |
|
|
Term
| two most important glycoproteins |
|
Definition
|
|
Term
| fiber forming ECM molecules |
|
Definition
|
|
Term
| space filling ECM molecules |
|
Definition
| glycoproteins and proteoglycans |
|
|
Term
|
Definition
| transmembrane receptor on cells for binding ECM proteins |
|
|
Term
|
Definition
| cell binding site on an ECM molecule |
|
|
Term
|
Definition
| cell attachment site of many adhesive proteins, Arg - Gly - Asp combination of nucleic acids |
|
|
Term
|
Definition
| cell adhesion nucleic acid sequence |
|
|
Term
|
Definition
| enhances osteoblast adhesion but not endothelial cells or fibroblasts |
|
|
Term
|
Definition
|
|
Term
| vascular endothelial cell growth factor |
|
Definition
| VEGF, blood vessel formation |
|
|
Term
| fibroblast growth factor family |
|
Definition
| FGF, cell division, angiogenesis |
|
|
Term
|
Definition
| NGF, neuron survival, neurite extension, neuron migration |
|
|
Term
| transforming growth factor beta |
|
Definition
|
|
Term
| bone morphogenetic protein |
|
Definition
|
|
Term
|
Definition
| hydrophobic nanoparticles/microspheres aqueous solution dropped into an organic solvent. Drops are collected from mixture and dropped into another solution, emulsifier |
|
|
Term
| hydrophobic nanoparticles/microspheres pros and cons |
|
Definition
pros: controlled release rate, small or large particles, high entrapment proficiency
cons: inflammatory, organic solvents, potential denaturation, low drug loading efficiency for hydrophillic drugs |
|
|
Term
|
Definition
| ratio of weight of drug entrapped int a carrier system to the total drug added |
|
|
Term
|
Definition
| ratio of the weight of the drug to the weigt of the total carrier system (drug plus polymer carrier) |
|
|
Term
| heparin binding growth factors |
|
Definition
| bFGF, GDNF, NGF, NT-3, PDGF, Sonic Hedgehog |
|
|
Term
| affinity based drug delivery pros and cons |
|
Definition
pros: high drug entrapment efficiency, water based, stable sustained release
cons: can only be used for growth factors that have binding affinity for heparin |
|
|
