tech and health - tissue-related technologies

Question 1

components of tissue engineering

Answer 1

1. engineering cells (cells, induced pluripotent stem cells, CRISPR)
2. engineering materials (growth factors, biomechanics, environmental factors)
3. engineering tissue architecture (3D printing, decellularized organs)

Question 2

regenerative medicine

Answer 2

engineering the properties of tissues and cells so they can be introduced to patients to regenerate damaged or non-functional tissue
- can involve combining biological tissue with synthetic materials (eg. repair of bone fractures or creating new tissue for treatment of ulcers and skin lesions in diabetes)

Question 3

3 essential components in processing

Answer 3

1. raw materials - cells, biomaterial/ scaffold, scaffold and cells
2. environmental factors - cytokinesis, growth factors, GENETIC MANIPULATION, mechanical forces, physiochemical factors, spatial and temporal signals, extracellular matrix molecules, cell surface molecules (immune system growth factors, blood cells)
3. engineered tissues - product (tissue substitute)

Question 4

CRISPR (clustered regulatory interspaced short palindromic repeats)

Answer 4

• gene editing tool
• molecular scissors that cut target DNA sequence
• palindromic sequence is when complementary strands are read the same in both directions (ex. GCA and ACG)
• CRSPR-CAS9 mechanism = adapted from defence mechanism against viruses of bacteria
• CAS 9 is an enzyme that uses guide RNA to cut target DNA
• when target DNA is found, CAS9 binds to DNA and cuts it which shuts off gene
• desired genetic sequence could add in repairing system for customized DNA
• modified versions of CAS 9 can activate gene expression instead of cutting DNA

Question 5

tissue engineering scaffold

Answer 5

combination of biological and synthetic

a raw material

gives structure to grow and become a healthy tissue

Question 6

essential components for scaffolds

Answer 6

1. CT scan
2. computational modelling (structural details to be pt specific)
3. FDM fabrication and manufacturing
4. 3DFD scaffolds are all unique
5. implantation of scaffold with cells (application)

Question 7

stem cells: adult stem cells (somatic)

Answer 7

• limited ability to be reprogrammed/ give rise to other cells!
• rare, undifferentiated cells (in bone marrow or fat tissues)

Question 8

stem cells: embryonic stem cells

Answer 8

• easy to reprogram/ regenerate or repair diseased tissue and organs!
• come from embryos that are 3-5 days old (embryo is a BLASTOCYST and has 150 cells)
• PLURIPOTENT stem cells (they can divide into more stem cells or become any type of cell in the body)

(explosive development for tissue engineering in a timeline)

Question 9

Henrietta Lacks (HeLa)

Answer 9

• her cells were taken without her knowledge
• first immortal cells grown in culture, still alive today
  -HeLa cells vital for developing polio vaccine, cancer secrets, viruses, and effects of the atom bomb
  -helped lead to IVF, cloning, gene mapping, bought and sold by billions

Question 10

adult stem cells (somatic)

Answer 10

reproduce, maintain, and repair tissue or organ where they are found

autologous: isolated and extracted from oneself
allogenic: isolated and extracted from other people

1960s
- bone marrow has:
- hematopoietic stem cells: from blood cells
- stromal cells: mixed cell population, generates bone, cartilage, fat, fibrous CT

Question 11

embryonic stem cells

Answer 11

• come from donated ‘spare’ embryos from IVF programs
  -unique capacities:
  
  • renew themselves indefinetely
  • become specialized cells (TOTIPOTENT - capable of developing into complete organism or differentiating into any of its cells or tissues, including extra-embryonic tissues - placenta and umbilical cord - EARLY STAGE of fetal development up to 8 cells)

(PLURIPOTENT - capable of differentiating into one of many cells (but not an entire organism)… BLASTOCYTE STAGE: preimplantation embryo of 30-150 cells, it consists of a sphere made up of an outer layer of cells (trophectoderm), a fluid-filled cavity (blastocoel) and a cluster of cells on the interior (inner cell mass) - potential to develop into any of 200 known cell types (but not extra - embryonic tissues)

Question 12

gastrulation of a diploblast

Answer 12

formation of germ layers from a blastula to a gastrula

some of the ectoderm cells (orange outer part) move inward forming the endoderm (red inside part)

Question 13

embryonic stem cells

Answer 13

human embryonic germ cells (come from medically terminated pregnancies)

sex cells (egg and sperm)
- occur at later stage in fetal development
- not PLURIPOTENT (email question)

Question 14

embryonic germ layer

Answer 14

endoderm (lining of GI)
mesoderm (bone marrow)
ectoderm (skin)

Question 15

mesenchyme - mesenchymal cells

Answer 15

cells of mesodermal origin, capable of developing into connective tissues, blood, and lymphatic and blood vessels

Question 16

what lab tests are used to identify embryonic stem cells

Answer 16

• no agreed standard test, many tests aren’t good indicators of cell’s most important biological properties and functions

quality of stem cells:
1. growing and subculturing the stem cells for many months (capable of long-term self-renewal)

2, determining the presence of surface markers that are found only on undifferentiated cells (Oct-4)

3. examining chromosomes under a microscope (whether chromosomes are damaged or amount is changed)
4. testing is human embryonic cells are pluripotent by:
   a) allowing cells to differentiate SPONTANEOUSLY in culture
   b) MANIPULATING cells so they differentiate to form specific cell type
   c)INJECTING cells into immunosuppressed mouse to test for formation of teratoma (benign tumor) - teratomas have a mixture of differentiated and partly differentiated cell types which indicates that embryonic stem cell can differentiate into multiple cell types)

Question 17

social scaffolding

Answer 17

stem cell research - so much public effort put into allow tissue engineering to be available

social = building up social support for something
scaffolding = important biomaterial for structure (holding cells/ mixtures)

ex. social scaffolding to promote stem cell research: stem cell research and cures act - support of public image christopher reeve which established institute for regenerative medicine $300 mil)

Question 18

applications of stem cell research

Answer 18

• cure incurable (parkinsons)
• repair damaged organs (heart and spinal cord)

-test drug toxicity (using human models instead of animals)

• immune system therapy in MS

Question 19

Parkinsons

Answer 19

neurodegenerative disorder (more than 2% of people)
- caused by progressive degeneration and loss of dopamine-producing neurons
- tremor, rigidity, hypokinesia (decreased mobility)
- first disease that can be treated w stem cell transplantation? - bc knowledge of DA neurons needed to relieve symptoms of disease, and many labs can induce embryonic stem cells to differentiate into cells with DA neuron functions

Question 20

uses of stem cells

Answer 20

stroke, baldness, learning defects, blindness, diabetes, cancers, chrons, bone marrow transplant, etc…

Question 21

for stem cell therapies to work, technologies must ensure that stem cells: (please dont say it for ava’s aid)

Answer 21

1. proliferate and generate enough tissue (for therapy)
2. differentiate into the desired cell types (ex. DA-neurons)
3. survive in the recipient after transplant
4. integrate into the surrounding tissue after transplant (minimize infection)
5. function appropriately for the duration of recipients life
6. avoid harming recipient
7. avoid immune rejection

Question 22

issues

Answer 22

drugs or devices

purity of bioengineered products

Question 23

ethical debate

Answer 23

what’s the moral status?
- harvesting embryonic stem cells destroys the blastocyst - murder

• embryonic stem cell research requires human cells, which could create a market for human cells, devaluing life
• if excess IVF embryos are being discarded, they should be put to good use (can be used to treat PD, diabetes, etc)
• can we use adult stem cells for same use?
• most countries (except africa and some other poor places) have flexible policy on embryonic stem cell research, only the US allows human reproductive cloning, maybe funds can be used to pursue stem cell research using IVF donated embryos from clinics

does US allow cloning or not?

Question 24

permissive

Answer 24

• permits research
• embryonic stem cell derivation techniques including cloning and SCNT (transfer of cell nucleus from somatic cell into an egg whos nucleus was removed) - aus, china, belgium, united kingdom (2.7 bil)

Question 25

flexible

Answer 25

from fertility clinic donations only, NO SCNT, certain restrictions, research only on remaining embryos not needed for reproduction (brazil, canada, france, SA, US) (1 bil)

Question 26

restrictive policy or no established policy

Answer 26

from prohibition of human embryo research to to permitting research on imported embryonic stem cell lines and limited number of previously established stem cell lines (austria, germany, italy, norway)

Question 27

black dots

Answer 27

leading genome sequencing research centers - indicate the level of scientific infrastructure and not whether stem cell genomic studies are being conducted at a given center

Question 28

where allows ES cell research (therapeutic cloning)

Answer 28

UK (US has no legislation yet)

Question 29

where allows ES cell research (creation of embryos for research)

Answer 29

US and UK

Question 30

where allows ES cell research (use of excess embryos from IVF clinics)

Answer 30

US, UK, Canada

Question 31

Canada’s embryonic stem cell legislation

Answer 31

• no law until recently
• federally-funded research covered by CIHR guidelines
• assisted human reproduction and related research act passed in march 2004

Question 32

what the canada act says about ES cells

Answer 32

use of existing ES cell lines - yes

use of excess embryos from IVF clinics - controlled (blastocyst destroy after 14 days, written consent, no selling, 18 yr old donor, 250,000 fine 5 yrs prison)

creation of embryos by IVF for ES cell research - no (500,000 fine 10 yrs prison)

therapeutic cloning - no (500,000 fine 10 years prison)

Question 33

assisted human reproduction agency

Answer 33

• established by act agency to issue licenses, inspect research labs, etc
• similar to UK human fertilization and embryology authority, except constrained by tighter legislation
• closed in 2012, its responsibilities were transferred to health canada

Question 33

reactions to act

Answer 33

too liberal
- failure to recognize humanity of human embryo (pro-life)

good compromise
- ALS society, muscular dystrophy association, PD society, support assisted human reproduction as it pertains to stem cell research (house of commons, health minister anne mclellan)

too restrictive
- nuclear transfer is controversial and why it should be regulated, but shouldn’t be banned (criminal law does not have the flexibility necessary to address this scientifically and socially dynamic area (UK human fertilization and embryology authority is a working model of a regulatory body, one with a long and honourble history)

*many approaches to evaluation - evaluating purity of materials, safety, making sure cells viable

Question 33

where allows use of existing ES cell lines

Answer 33

US, UK, Canada, Germany