TE 4

Question 1

Differences in terms of regenerative medicine and tissue engineering?

Answer 1

Regenerative medicine is an umbrella term including tissue engineering, but not exclusively e.g. cell based therapies may involve no TE, whereas TE of food does not come under regnerative medicine etc

Question 2

Why the need to TE food?

Answer 2

• UNSUSTAINABLE FOOD PRODUCTION.
• Water useage of agriculture 70%, 37% of landmass (besides antarctica) is agriculture, and worse for greenhouse gases than whole of transport sector.
• Worldwide meat production is increasing, and the population is increasing.
• Predicted 69% increase in food calories needed from 2006 to 2050.
• animals in confined spaces- Antibiotic resistance
• Ethics- growing animals just for slaughter and use of the most basic tissues.
• Space missions

Question 3

Who famously proposed TE early of animals for food?

Answer 3

1930s churchill said the absurdity of growing chickens just to eat their breast or wing, and that in the next 50 years we would just grow that part.

Question 4

Example of lab grown tissue?

Answer 4

Lab grown burger 2013. Grew the skeletal muscle.

Question 5

about lab grown burger

Answer 5

vv

Question 6

How does muscle regenerate/grow?

Answer 6

1. Injury activates satellite cells (muscle specific precursor stem cells). (Notch and Wnt signalling sometime)
2. Satellites proliferate.
3. Satellites differentiate into a myoblast.
4. Myoblasts fuse into myotubules
5. Mature into myofibers. (MyoD, myogenin etc)

Question 7

Basic how would lab meat be grown? (4)

Answer 7

1. Biopsy taken from animal,
2. isolated satellite cells,
3. culture- proliferative phase,
4. differentiation phase. Into myoblasts, fuse to myotubules and then mature to myofibers.

Question 8

Disadvantage of satellite cells for lab grown food? Instead?

Answer 8

They cannot proliferate indefinitely. Can increase in numbers 50-70%, so need to source a lot of cells- still taking biopsies from animals- causing them harm.

Question 9

Properties biomaterial scaffold for meat should have?

Answer 9

Digestible, non-allergenic non-toxic, not have bad taste/texture, support the satellites maturation and differentiation

Question 10

Biorectors for food growth?

Answer 10

One study put myoblasts onto pourous collagen microspheres and put into bioreactors. BUt muscles need some sort of anchorage and have mechanical and electrical stimulation within the bioreactor.

Question 11

How could muscle tissue be created into a more organised structure?

Answer 11

3d Printing muscle tissue. E.g. make a finer texture like a steak

Question 12

Difference between regenerative medicine and food TE manufacture?

Answer 12

Medicine- Mainly academia research- complete transparency of protocols etc,
Food- private companies- commercial- don’t publish their protocols all patterned etc- so hinders progress.
Also Public acceptance bigger issue.

Question 13

Scale of food production?

Answer 13

Would have to be huge- calculation of 1 bioreactor for every 10 people- environmental footprint large and huge volume of media needed.

Question 14

Advantages of TE meat over animal?

Answer 14

• Ethics
• Sustainability?
• Control over taste/flavour
• Healthier- add vitamins, reduce fat etc.
• New range of products- more exotic animals?

Question 15

TE Leather production how?

Answer 15

1. Take skin sample from animal
2. isolate and multiply cells.
3. deposit onto sheets and induce collagen production
4. Layer sheetds and fuse layers into a solid hyde.
5. Treatment- Tan, dye etc.

Question 16

TE Leather vegan?

Answer 16

“modern meadow” now changed to produce vegan leather from yeast or bacteria.

Question 17

Key Historical events that have shaped the regulation of medicines?

Answer 17

‘Elixir Sulfanilamide’ incident 1930’s- Drug for staphylococcus infection- dissolved in antifreeze. 4/100 children died in trial.
The Nuremberg Code-Tested on prisoners during WWII- then law came out that an testing should be on informed and voluntary people.
The thalidomide incident 1950’s: Noted need to not only test short term effects but also long term safety.

DECLARATION OF HELSINKI 1964. Statement of ethical principles for medical research.
GOOD CLINICAL PRACTICE- have to prove efficacy and safety on animals and have well trained staff with reproducible protocols.

Question 18

Problem with regulation of TE products?

Answer 18

It doesnt fall within the relms of medicinal products or medical devices but between the two. Cell therapy and gene therapy also between, so new regulation was needed “advanced therapies” under EU regulation. Require case- by- case consideration- not set trials.

Question 19

major concerns with using cells in TE products?

Answer 19

Cancerous e.g. EB boy. Unpredictable as living cells evolve (Epigenetic changes), migrate (different environmental cues here?) and interact with other cells.

Question 20

3 Things advanced therapies need by EU regulation?

Answer 20

1. Establishment of maufacting process and controls (robust and reliable) E.g. Age related macular degeneration protocol have to say the QC steps for each step. E.g check cell appearance, Karyotype (tumourgenic) cell counts, sterilise etc
2. Pre-clinical safety and efficacy in relevent models.
3. Clinical trials in human participants (involve surgery so only can give to patients really- ‘one off compassionate treatments’)

Question 21

Choice of animal models for Advanced therapies?

Answer 21

Just have to use the most appropriate model. E.g. mice good as small and cheap but depends what for as their cartilage regenrates better than ours for example, so horse may be more suitable. E.g. cats often for cochlea implants similar strucutre, not minute.

Question 22

4 things basic to consider for TE constructs?

Answer 22

Safety, engraftment (e.g. vascularisation), functionality and immune response

Question 23

Things to consider in trial for advanced therapies which may be different to normal medicinal products?

Answer 23

1. Small exploratory trial on small number of patients- unethicial to do surgery on healthy inviduals.
2. Means not blinded as patient knows whether had surgery or not.
3. Surgery often depends on how good the surgeon is, comparison may be difficult.
4. Can standardise though to an extent- ensure patients got same thing wrong and same check ups and aftercare etc, but the wound may vary and patients responses.
5. Defining the competitor- drugs are often put in comparison to the current drug treatment but this may not be possible as may not be an alternative.
6. Dosing- not if construct, but if cells involved- how many?

Question 24

Challenges of commercialisation of medicinal products compared to shop items etc?

Answer 24

Unlike in shop where customer decides whether to buy something, its the government (NHS) that pays so balancing act of cost budgetting. Dependant upon politics.
Risk benefit assesment by doctor. Can give one off compassionate treatment of advanced therapies (Hospital exeption) if desperate etc.

Question 25

TE market?

Answer 25

Growing in last 10 years x6 the worth- $30million industry. But lack of pharma company investment as lack of return its high risk and takes so long to market not worth it for their return.

E.g. Dermagraft by Advanced Tissue Sciences company bankrupt.

Question 26

Casestudy of pharma company that tried to invest in Advanced therapy?

Answer 26

Advanced Tissue sciences developed Dermagraft- skin replacement for burns patients- estimated 25,000 burns victims need skin replacements (US) a year, so $750million market, and skin ulcers another $750mil.
1991 developed. Expected FDA approval by 1995- but because such a new product didnt know how to test took until 2001. Bankrupt company.

Question 27

Why did Dermagraft company fail (Advanced tissue sciences)?

Answer 27

1. Lengthy regulation approval (10years)
2. Manufacturing was challenging.
3. Transportation difficult, living cells need to be local.
4. $4000 and needs lots of follow ups- more expensive than other alternatives.

Question 28

Bottlenecks in commerical development of TE products?

Answer 28

1. Financial rewards risky
2. Case- by- case regulation pathway, not straightforward
3. Manufacturing scale up complex and expensive.
4. Distribution and storage complicated- living cells.

Question 29

Number of tissue engineering companies now?

Answer 29

Now nearly 1000 regenerative medicine companies worldwide. $13 billion industry