Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS3 > Regenerative Medicine > Flashcards

Regenerative Medicine Flashcards

1
Q

Regenerative medicine incorporates the body’s …. with ….. to recreate and rebuild cells, tissues and organs

A

The body’s self-healing methods with foreign biological materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Clinical needs for RM is:

A

organ failure caused by:
injury
disease
ageing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Current treatments for organ failure are:

A 
Surgical reconstruction.
Mechanical devices (pace makers, dialysis).
Transplantation (hip replacements)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Limitations of surgery:

A

complications such as shock, bleeding, infection, thrombosis, embolism, reaction to anaesthetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Problems of transplants are:

A

donor’s tissue dies, immunosuppressants are required, transplants have limited source, rejection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mechanical device problems are..

A

they do not perform the full function of tissues and they cannot grow with tissues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When building a tissue, …. aspects are considered (5)

A

biological, cellular, genetics, anatomical and chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Bovine cartilage was first engineered on… What was it used for?

A

a mouse in the shape of a human ear. This was only a cast and used as a scaffold for seeding cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What was wrong with the ear grown on mouse?

A

Mouse provided nutrients for growth however there was no skin coverage and poor mechanical stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Aims of RM are to provide new solutions for treatment of organ failure which have…

A

minimal immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

building blocks of tissues are:

A

scaffolds/biomaterials.
bioactive molecules.
cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which tissues compose the structure of an organ?

A

Epithelial, nerve, connective and muscle - provides support and vasculature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Wound healing has 3 stages:

A

Inflammatory
Proliferative
Remodelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What occurs in the inflammation stage.. (3)

A

blood clot forms.
leukocytes clean the wound.
viscosity of blood increases for slower blood flow around the injury.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In the proliferative phase of wound healing..(2)

A

Blood vessels re-grow.

New granulation tissue forms from fibroblasts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Remodelling stage of wound healing is the longest and involves..(3)

A

organisation of new tissue.
regenerating epithelium.
formation of scar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

After 3 months of wound healing, there is regeneration of …% of original strength

A

70-80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

There is regeneration, repair or fibrosis of wounds depending on..

A

severity of the wound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Fibrosis is … due to…

A

scar formation due to persistent tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Cells used in RM are:

A

Autologous.
Allogeneic.
Xenogenic
Syngenic/Isogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Xenogenic cells are from..

A

a different species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Syngenic/Isogenic cells are from..

A

a genetically identical individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What type of cells have the potential to induce immune response and transmit disease?

A

Allogeneic and xenogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Autologous and allogeneic cells can be ES, iPSCs or adult stem cells. These can be…

A

multipotent or pluripotent., with different abilities in reproducibility.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Differentiated cells are advantageous as..

A

they have functionality, unlike ESCs/foetal tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cells used are cultured in growth medium which replaces the function of… Medium consists of…

A

Replaces function of blood. Consists of growth factors and nutrients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Laminar hoods are used with cell cultures in order to…

A

keep the environment clean and microbe-free.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Other factors controlled in cell cultures are:

A

temperature, humidity and gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

For biomaterials and cells to interact, what is needed?

A

Properties of biomaterials for attachment of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Attachment of cells is usually done by … which provides…(5)

A 
The ECM provides:
structural support.
mechanical properties.
bioactive cues.
regulates growth factors.
scaffolds for tissue renewal.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

ECM consists of (depending on type of tissue):

A

fibrous structural proteins - collagen, elastin.
adhesive glycoproteins - fibronectin, laminin.
water hydrated gels - proteoglycans, hyaluronan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Collagen forms ….% of ECM and has a … structure.

A

80-90%. It has a triple helical structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Proteoglycans are water hydrated gels and are composed of…

A

glycosaminoglycan chains linked to a protein core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Adhesive molecules such as …. have … sequences which mediate cell attachments.

A

Fibronectin and Laminin have RGD sequences to mediate cell attachments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

RGD sequences consist of which amino acids?

A

Arg-Gly-Asp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Integrins recognise most ECM proteins and help with…

A

cell attachments and activating signalling pathways.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

GMP ensures that medicinal products are…

A

consistently produced and controlled to quality standards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

biomaterials are mainly used to..

A

develop scaffolds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

The first biomaterial was used in..

A

intraocular lenses (contacts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Properties of biomaterials evolved from.. to…

A

from bioinertness, bioactivity to functional tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Materials MUST be..

A

biocompatible - have an appropriate host response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Biocompatibility includes resistance to..(3)

A

blood clots
bacterial colonisation
allow normal healing processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Properties of biomaterials to consider:

A

physical/mechanical.
chemical.
biological.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Physical properties of biomaterials are their:

A

strength, elasticity and architecture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

chemical properties of biomaterials include:

A

degradability - all products and intermediates need to be non-toxic.
resorption - elimination of byproducts.
water content.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

biological properties of biomaterials are:

A

interactions with cell and ECM.

release of bioactive signals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

A common biomaterial is … what are its properties?

A

Polymers are large molecules made of chains or rings of monomers. They have molecular weights of 200,000 Da

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

When polymers are dehydrated, they are:

A

hard and brittle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Some polymers are hydrophilic and can…

A

swell up and represent soft tissue/hydrated natural tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are hydrogels?

A

cross-linked polymer networks which are insoluble but swell in aqueous medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

The 3 major classes of biomaterials are:

A

Natural
Synthetic
Semi-synthetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Natural biomaterials can be made of:

A

Proteins - collagen, gelatin, silk, fibrin, elastic and soybean.
Polysaccharides - chitosan, alginates, hyaluronan and chondroitin sulphate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Natural biomaterials can be difficult to…and induce….

A

Difficult to source.

Can induce immune response (antigens).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Synthetic biomaterials are polymers such as:

A

Polylactic acid (PLA), Polyglycolic acid (PGA), Poly(lacti-co-glycolic) acid (PLGA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Synthetic materials have advantages of:

A

can be tailored to suited needs.

produced on large scale.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Synthetic materials have questionable functionality since..

A

they are based on bio-mimicry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Semi-synthetic biomaterials are hybrid molecules of…

A

Bio-active macromolecules on synthetic polymers - (Polyethylene glycol)-fibrinogen (PEG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Semi-synthetic materials allow for…

A

different properties of both natural and synthetic materials.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

PEG is semi-synthetic and has… It can control..

A

biofunctional domains (RGDs). It can control density, stiffness and biodegradability.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Different bulk and surface properties are needed of biomaterials in different clinical situations. Contact lenses need to be…

A

transparent, refractive, hold their shape, allow O2 into the cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Surface properties of biomaterials are modified by..

A

altering molecules or atoms.

overcoating existing surfaces with another material - can create texture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Material surface affects protein adsorption. This is important since..

A

cells do not directly interact with the material; they interact with a layer of protein which plasma adheres to.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Materials which resist protein adsorption/cell adhesion are called..

A

non-fouling surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Non-fouling surfaces could be useful for..

A

inhibiting bacterial colonisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

cell adhesion occurs through membrane receptors and …. of materials

A

the RGD domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

cellular responses to materials vary with..

A

RGD density of the material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

surfaces can be patterned by:

A

micrometer-scale chemical patterning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Scaffolds take the role of ECM providing:

A 
structural support.
mechanical properties.
biological cues.
growth factor actions.
reg of proliferation and renewal.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

When designing scaffold, what needs to be considered? (6)

A 
material science.
scaffold architecture.
scaffold-cell interactions.
up-scaling.
3D models.
nutrient supply.
biodegradability.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Biodegradability is important as it reduces..

A

number of surgeries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Porosity if important for..

A

cell attachment through RGD domains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Acellular tissue matrices are made by..

A

de-cellularising normal tissues which leaves behind collagen, fibronectin and GAG fibres.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

acellular matrices are good because..(4)

A

antigens and cellular components are removed so that new cells can attach to the scaffold.
Reduced immune response.
Exploit 3D structure of ECM in real tissues.
Commercially available.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

If de-cellularisation is not done completely, what can happen? (3)

A

Endotoxins and bacteria can contaminate the sample - causes scar tissue.
Incorrect cell encapsulation.
Effects cross-linking.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Acellularisation is checked by…

A

staining for cells in the matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What has been made by acellularised matrices?

A

Mitral and aortic valves from pig hearts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Scaffolds are fabricated by: (5)

A 
Porogen leaching.
Phase separation.
Electrospinning.
Additive manufacturing.
3D printing.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

porogen leaching mixes … with polymer gel paste. What is the process?

A

effervescent salt particles. The gel is moulded then placed in water for the salt to be leached. It is then ‘freeze-dried’ to create a porous scaffold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Phase separation mixes … and … which undergo separation and freeze-drying to create nanofibrous hybrids.

A

gelatin and silica

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Electrospinning spins polymer solution by using..

A

electric fields. Polymer is reeled and collected, and then made into scaffolds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Additive manufacturing joins materials… Produces..

A

layer by layer to make 3D models. It produces precise morphologies but can only be done with limited biomaterials.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

3D printing is new and upcoming. It can design organs through… and … However it is…

A

MRI scans and digital 3D modelling. It is very damaging to cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

An example of 3D printing is skeletal muscle. This was done using..

A

Mouse myoblasts.
PCL pillars for structure and cell alignment.
It was cross-linked with thrombin so it gelated to fibrinogen.
Unwanted material was dissolved.
Matured into functional muscle in rats.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

small molecules are being used to induce tissue regeneration. Eg..

A

Corticosteroids, hormones, proteins, oligonucleotides, RNA, DNA and BMPs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Biomaterials are made to sequester BMPs by…

A

physically entrapping rhBMP2 into PEG by mixing before the gelation process.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

In materials which sequester BMPs, cell adhere and secrete MMPs which…

A

induce proteolysis so that gels release BMPs, allowing them to diffuse and locally act to signal osteoblast precursors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Spider can make .. different types of silk with different…

A

7 types of silk with different functions and properties such as strength and stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Silk with kinks due to proline residues allow..

A

toughness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Silk has been made into..(2)

A

silk sheets and nanowires (delivery/scaffolds)

90
Q

Growing cell cultures is cheap and easy, but without mixing causes:

A

conc. grads. to occur.

issues with growing.

91
Q

Bioreactors are dynamic culture systems which mix cultures, giving rise to…

A

homogeneous conc. of nutrients, toxins and other components

92
Q

Bioreactor roles: (4)

A

establish spatially uniform cell distrib on 3D scaffolds.
overcome mass transport in 3D constructs.
exposure to physical stimuli.
control pH and O2

93
Q

When cells are distributed on 3D scaffolds, they need:

A

high seeding efficiency.
short inoculation period.
uniform distrib. within the scaffold.

94
Q

If cells are static in 3D culture, cells accumulate..

A

on the top of the material

95
Q

physical conditioning is using hydrodynamic forces on cells such as…

A

smooth and skeletal muscle and lung tissue - endothelial cells are normally under stress and muscles have constant tension

96
Q

Basic bioreactor requirements: (2)

A

biocompatibility and sterile containment

97
Q

Rotating wall bioreactors keep scaffolds…

A

in suspension

98
Q

Perfusion bioreactors keep the culture medium… Has been used for..

A

constantly circulating through the TE construct. Used for heart, lung, liver and pancreas

99
Q

compression bioreactors use … stimulus to move constructs

A

mechanical

100
Q

Perfusion bioreactors are good for decellularisation, results in…

A

retention of organ structure

101
Q

defective heart valves are either..

A

surgically repaired or replaced (with prosthetics)

102
Q

Heart valve cells are exposed to … and … in vivo

A

mechanical stretch and hydrodynamic shear stress

103
Q

A Flex-Stretch-Flow bioreactor mimics … for heart valve tissue. Allows..

A

mechanical stimulation and perfusion.

Allows laminar flow and media flow over the scaffold

104
Q

challenges of bioreactors are: (2)

A

mimicking native cell behaviour.

scale up - most bioreactors have low volume output

105
Q

Skin constitutes for ..% of body mass. Its functions are..

A

10%. Functions in protection, regulation and sensation.

106
Q

Skin structure has layers:

A

epidermis, dermis, hypodermis

107
Q

The epidermis consists of what cells? It has no…

A 
Keratinocytes - tough
Melanocytes - UV
Langerhan's - APCs
Merkel - mechanoR
Has no blood vessels
108
Q

Dermis is the bulk of the skin. It consists of..(7)

A

collagen, elastin, glycosaminoglycans.
fibroblasts.
blood vessels, hair follicles, sebaceous and sweat glands.

109
Q

Hypodermis is composed of a network of …. It functions as…

A

adipose cells and collagen - mainly acellular.

Functions as a thermal insulator, shock absorber and stores fat.

110
Q

Contracture of skin is tightening of scars. Caused when the …. layer of … is perturbed

A

basal layer of epidermis

111
Q

Needs for skin replacement:

A

Acute trauma
Chronic wounds
Surgery
Genetic disorders - bullous conditions

112
Q

Most common reason of skin loss are … which cause … wounds

A

burns - cause rapid and extensive wounds. Damaging of large skin areas can lead to death.

113
Q

Skin wounds are typed into:

A

Epidermal
Superficial partial-thickness
Deep partial-thickness
Full thickness

114
Q

Epidermal wounds cause…

A

redness, minor pain, no scarring

115
Q

Superficial partial-thickness wounds affect the.. Wound appearance..

A

epidermis and superficial parts of the dermis.
Wet and weeping, red blisters.
Painful due to exposure of sensory nerves.
Heal spontaneously.

116
Q

Deep partial-thickness involves greater dermal damage. Wound appearance is:

A

Moist, white/red/pink.
Fewer skin appendages remain.
Scarring more pronounced.

117
Q

Full thickness skin wounds have complete destruction of regenerative epithelia. Appear:

A

dry, leathery and rigid.

No spontaneous healing.

118
Q

Treatment of major skin injuries are:

A

early excision of dry scab.
wound closure.
skin grafts.

119
Q

Skin grafts differ by their thickness:

A

split thickness and full thickness - amount of dermis

120
Q

Skin grafts are usually autologous and skin is…

A

Taken from a non-injured site with no blood supply.

Meshed to cover the large wound

121
Q

Once a skin graft has been placed, inosculation occurs. This is..

A

the process of revascularisation

122
Q

Skin grafts need to…

A

adhere to the wound bed with no bleeding, infection or movement.
needs a thin layer of connective tissue

123
Q

Allografts are used for… Possibilities of…

A

temporary prevention of fluid loss and wound contamination.

Could cause pathogen transmission and immunogenic rejection

124
Q

Skin substitutes are needed due to..

A

limited availability of skin grafts.
pain and scarring form donor site.
further pain inflicted on patient.

125
Q

There are no ideal skin substitutes yet. For epidermal substitutes what has been used?

A

Keratinocytes from skin biopsies. They are expanded in culture and delivered to the wound

126
Q

Keratinocytes have been delivered to wounds by..

A

synthetic silicone delivery.

Spray suspension

127
Q

Combination of epidermal substitutes with …. is needed to achieve full thickness healing

A

dermal substitutes

128
Q

Dermal substitutes are..

A

acellular.
applied onto a prepared dermis.
Alloderm.

129
Q

Full thickness burn is treated by a 2 step process:

A

first applying dermal substitute, followed by an epidermal cover

130
Q

Apligraf is bovine type 1 collagen cultured with…

A

allogeneic neonatal fibroblasts and keratinocytes. Resembles normal skin structure

131
Q

OrCel is cultured allogeneic fibroblasts and keratinocytes from neonatal foreskin. How does it promote healing?

A

Fibroblasts are seeded into bovine collagen sponge with keratinocytes on top. Cytokines and GFs from the product promote host cell migration and healing.

132
Q

Limitations of skin replacement strategies:

A

Wait 3-12 weeks after a biopsy is taken.

Currently available substitutes only use 2 cell types - no sweat glands/hair

133
Q

Epidermolysis bullosa is..

A

spontaneous skin blistering which is lethal due to infection, sepsis and skin cancer

134
Q

Blistering of skin is the epidermis.. Normally it is..

A

separating from the dermis repeatedly.

Normally layers adhere through integrins and laminin

135
Q

In epidermolysis bullosa, … is mutated, causing no dermal-epidermal interaction in basal lamina

A

Laminin 332 (splice site)

136
Q

In one patient of epidermolysis bullosa, autologous graft could not be done because…

A

not enough skin available.

skin cells had mutation

137
Q

In skin gene/cell therapy, genes were manipulated into autologous fibroblasts by…

A

retrovirus delivering correct LAMb3 into cells.

NGS was done to make sure LAMB3 integrated in right place (not in oncogene)

138
Q

After LAMB3 corrected cells were transplanted, what was seen?

A

after 21 months, no blisters, not tumourigenic, laminin 332 expression

139
Q

Epithelial tissue has been approached by EB formation from iPS. What was used to enhance hair shaft production?

A

Wnt3b - approach produced extra appendages of skin - sebaceous glands, fat, errector pili muscles, nerves

140
Q

Skin substitutes can also be used in vitro for…

A

cosmetic testing - l’oreal
disease modelling
drug discovery

141
Q

Other skin disorder substitutes can be used for:

A

Vitiligo
Psoriasis
Sin cancer
Allergies

142
Q

Corneal disease affects corneal function:

A

transparency, refractive power and eye protection

143
Q

Corneal epithelia has functions of:

A

prevents fluid loss.
create barrier to pathogens.
respond rapidly to wounds.

144
Q

Corneal stroma is …% of thickness. It consists of… and provides strength and transparency.

A

90% of corneal thickness.

Consists of collagen, proteoglycans, glycoproteins

145
Q

Keratocytes in corneal stroma are long, thin flattened cells. What do they do?

A

synthesise and maintain the ECM of stroma

146
Q

Corneal endothelium has functions of:

A

maintaining stromal hydration - for transparency.

Has pumps/channels to allow solutes and nutrients from the aqueous humor through.

147
Q

Corneal innervation is important for:

A

blinking, wound healing, tear production

148
Q

Corneal transplants are doable. If they fail, Keratoprosthesis can be used. This needs..

A

life-long antibiotics.

meds to control inflammation and glaucoma.

149
Q

corneal disease can arise from:

A

epithelia - limbal deficiency
stroma - dystrophy
endothelia - bullous keratopathy

150
Q

Limbal cells have a stem cell niche which produce…

A

post-mitotic wing cell layer

terminally differentiated cells - squamous layer

151
Q

Limbal stem cell deficiency can cause:

A

aniridia, sclerocornea, conjunctiva overgrowth, ocular burns

152
Q

Ocular surface can be restored in ocular burn patients through..

A

limbal epithelial stem cell transplantation

153
Q

Corneal stem cell transplant used in Holoclar. What is seen?

A

Stable corneal surface.
little/no ingrown blood vessels.
reduction in pain and inflammation.
vision improvements.

154
Q

Stromal replacements need to be:

A

acellular.

promote repopulation

155
Q

Biomaterials used in stromal replacement:

A

human collagen cell-free implants - this is endogenous, repopulates nerve and stromal cells. Not great improvement of visual acuity.

156
Q

Challenges in treating corneal diseases:

A

need to recreate epithelium - this needs constant replacement, needs to maintain integrity and have transparency.
recreating stroma - needs transparency and high tensile strength.
Re-innervation is limited - use growth factors?

157
Q

Corneal endothelium does not regenerate in humans. In culture they show…

A

limited proliferative ability. Should be derived from PSCs instead

158
Q

Peripheral nerve injuries are mainly caused by:

A

car accidents

159
Q

Axons are enclosed by … Groups of axons are bound together by … and fascicles are bound by …

A

Axons surrounded by endoneurium.
Groups bound by perineurium to form fascicles.
Fascicles joined by epineurium.

160
Q

3 types of peripheral nerve injury:

A

Elongation
Laceration
Compression

161
Q

Neuropraxia is…

A

no/little structural damage, no loss of nerve continuity.

symptoms are reversible.

162
Q

Axonotmesis is …. perineurium and epineurium still intact

A

complete interruption of axon and its myelin sheath. Axon is divided

163
Q

Neurotmesis is complete disconnection of the nerve and surrounding stroma. What is seen?

A

No spontaneous recovery.

Weakness and atrophy

164
Q

Wallerian degeneration is …and includes..

A

degeneration of the nerve fibre and myelin sheath past the point of the cut - with macrophages (debris), proteases and bands of Bungner

165
Q

In regen of CNS, macrophages infiltrate slowly which delays..

A

removal of inhibitory myelin

166
Q

In the CNS, reactive astrocytes produce..

A

glial scars which inhibit regeneration

167
Q

Repair in the CNS is … whereas repair in PNS is…

A

CNS=inhibited repair.
PNS=actively promoted repair.
NSs need different strategies

168
Q

Approaches to repair PNS tissue so far:

A

Surgical reconstruction
Grafts
Nerve conduits

169
Q

Reconstruction of nerves can cause tension which … If the nerve is stretched by 8%…

A

reduces blood flow. when nerve is stretched 8%, blood flow reduces to 50%. The nerve is completely ischaemic at 15% stretched.

170
Q

Autologous nerve grafts adv/disadv:

A

low risk of immune response.
LOF at donor site.
2 surgeries required.
limit to size and type

171
Q

Nerve conduits are guides for regenerating axons. They prevent … and increase conc of…

A

Prevent infiltration of scar tissue.

Increase concentration of intraluminal proteins

172
Q

The nerve conduit connects to proximal and distal nerve stumps. It then fills with…

A

Conduit fills with plasma.
Fibrin cable forms.
Cells migrate and axon regenerates.
Tissue reforms but notably thinner.

173
Q

Decellularised nerve conduits provide 3D scaffolds with…

A

clean pathways to allow migration.
Well distrib. for regeneration.
Porosity for plasma to pass through

174
Q

Natural and synthetic materials have been used for nerve conduits including:

A

Chitosan, collagen, fibrin, fibronectin, keratin.

PLA, PLGA, PEG, silicone

175
Q

For nerve conduits to be successful the injury gap must not be too large. At longer lengths…

A

thinning of fibrin cable restricts regeneration

176
Q

To increase the critical gap length of nerve conduits, approaches could be:

A

ECM components.
Intraluminal support.
Neurotrophic factors.
Cell grafts.

177
Q

ECM components for increasing critical nerve gap are matrices. These include:

A

Weak viscoelastic hydrogels - high water content.

Laminin, fibronectin, collagen

178
Q

Intraluminal support to increase critical nerve gap include:

A

micro-grooved luminal design.
variations in conduit designs.
surface functionalisation.
intraluminal guidance.

179
Q

Functionalisation of nerve guides uses neurotrophic factors eg. NGF and NT3. These will:

A

support axonal growth.
support prolif and migration of Schwann cells.
increase neuroprotection through intrinsic pathways.

180
Q

Delivery of neurotrophic factors in nerve conduits is done by controlled release methods of:

A

diffusion-based.
suspension.
affinity-based.
microsphere encapsulation.

181
Q

Schwann cells are criticcal for successful nerve regen as they induce:

A

Bands of Bungner.
Secretion of NT factors.
Proliferation

182
Q

Nerve gaps larger than 15mm..

A

cannot be sutured

183
Q

…. is usually used in nerve conduits and it degrades over time.

A

Bovine type 1 collagen

184
Q

PVA can be used in nerve conduits however it is not … Fibrosis can occur after 5 years which causes…

A

PVA is not degradable. Fibrosis causes neuropathic pain - conduit must be removed.

185
Q

Microstereolithography uses … to turn synthetic materials into solids.

A

UV light and photocatalytic reactions.

186
Q

Axons wander in conduits. How is this improved?

A

Lining lumen with PCL fibres at 8 micrometer depth for neuron growth.

187
Q

Nerves have better outgrowth if there is good … This can be shown by altering..

A

Needs good cell adherence. Done by altering surface chemistry.

188
Q

Stiffness of conduits is reduced by making them..

A

more porous

189
Q

Tissues grown in vitro need bioreactors, in vivo they need..

A

vascularisation

190
Q

Roles of vascularisation:

A

avoid graft necrosis.
generate thicker tissues.
help graft innervation.
improve graft function.

191
Q

Formations of blood vessels are…

A

macrovessels - arteries and veins.
microvessels - arterioles and venules.
capillaries

192
Q

Cells need to be located close to capillaries. If islet cells are more than…. they necrose.

A

100 micrometres

193
Q

vasculogenesis is creating a primary capillary plexus from..

A

mesoderm, hemangioblasts, forming tubes and making plexuses.

194
Q

Important factors of angiogenesis are:

A

VEGF - vascular endothelial growth factor

195
Q

Arteriogenesis can be caused by …

A

increasing shear stress - causes endothelial cells to release TGFb, prolif and matrix remodelling.

196
Q

…scaffolds facilitate vascular ingrowth

A

porous

197
Q

scaffolds are functionalised for vascularisation by:

A

Controlled growth factor delivery, single or combo - VEGF, PDGF, bFGF.

198
Q

During vasculogenesis, VEGF signals to endothelia which secretes..

A

MMPs. This creates punctures in the BM, allowing vessel sprouts to form. Matures by recruiting SMC and pericytes.

199
Q

Vascularisation is in a feedback loop with..

A

hypoxia

200
Q

VEGF is not sufficient to induce maturation. What does this?

A

PDGF - platelet derived growth factor

201
Q

VEGF and PDGF are used together to form vessels by 2 steps:

A

1 release VEGF to stimulate growth of immature vessels.

2 PDGF from encapsulated microspheres to facilitate maturation

202
Q

Distinct kinetics which mimic natural process and use of multiple angiogenic factors is..

A

important for engineering artificial vessels

203
Q

Disadv. of strategies facilitating vascular ingrowth:

A

time consuming - microvessels grow 5 micrometres per hour.

may not be sufficient to prevent necrosis in 3D constructs.

204
Q

Prevascularisation strategies have been designed to improve vascularisation. In vitro is:

A

Build a prevascular structure so the prevascular network can anastomise with existing blood vessels - this is faster than new blood vessel formation.

205
Q

In vitro prevascularisation shows endothelial cells can:

A

spontaneously self-assemble into capillary structures.

however there are issues with mature cells.

206
Q

In vivo prevascularisation involves:

A

implanting a scaffold into a well vascularised tissue.
Microvessels ingrow from the host.
Implant is then transferred to the defected site.

207
Q

In vivo prevascularisation can be done by the flap technique:

A

Scaffold is implanted into a muscle flap.
Entire flap is transferred.
Vascular pedicle of flap is surgically anastomised to host vessels.

208
Q

Another in vivo prevascularisation technique is AV looping:

A

Use a vein to form a shunt loop between artery and vein.
This leads to spontaneous vessel sprouting.
Loop is placed in a protective chamber then transferred.

209
Q

In AV loop technique, tissue is not embedded in..

A

surrounding muscle tissue

210
Q

Considerations of vascularisation strategies:

A

Scale up
Cost
Minimal invasiveness

211
Q

TE constructs have .. and … interactions with the body. Causes .. and .. responses.

A

Local and systemic interactions.

Inflammatory and immune responses

212
Q

Biomaterials effect processes of:

A

wound healing.
infection.
toxicity.
tumourigenicity.

213
Q

The body’s effects on biomaterials are:

A

enzymatic degradation.
calcification.
abrasion.
corrosion.

214
Q

Tissues respond to implants by… This involves:

A

fibrous encapsulation. Involves abundant deposition of ECM and isolation of biomaterial from local tissue

215
Q

Implant infections such as Staphlococci occur because bacterial develop..

A

biofilms. - these are resistant to antibiotics and host defence

216
Q

Biofilms allow bacteria to embed themselves in the..

A

matrix

217
Q

Floating bacteria compete with cells and proteins to make interactions with…

A

biomaterial surface

218
Q

Using biomaterials with non-fouling surfaces can inhibit..

A

bacterial colonisation

219
Q

Bacterial colonisation could also be prevented by..

A

using bacteria-repelling proteins

220
Q

Byproducts of physical and chemical wear can enter the bloodstream eg…

A

metal on metal hip replacements release cobalt and chromium in the blood.

221
Q

A way to avoid immune response is by immunoisolation. What is this?

A

Uses selectively permeable membrane to enclose biomaterials in - differ in size

222
Q

Immunoisolation has been done with..

A

stem cell derived islet cell therapies

BMS3 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions