Cell and Tissue Quiz 1

What Is Tissue Engineering?

Tissue engineering is a multidisciplinary field that aims to fabricate biological substitutes that restore, maintain, or improve tissue function for medical purposes such as skin grafts and organ transplants.

Why do we need tissue engineering?

Tissue engineering is necessary to address the shortage of donor organs and to provide solutions for repairing or replacing damaged tissues in a wide range of medical conditions.

Are the Terms Tissue Engineering and Regenerative Medicine Interchangeable?

Although related, tissue engineering focuses on creating biological substitutes, while regenerative medicine encompasses a broader range of therapies aimed at repairing or regenerating damaged tissues and organs. (square is not a rectangle situation)

What are other sources of cells? (not the patient)

Cell banks, as you typically need more cells than what you will be able to take from the patient

True or False: starting cells MUST be able to serve as the specific desired cell/tissue

TRUE… if you need brain tissue, the stem cell must have the capability to become nervous tissue

Bioreactors

Though not necessarily a part of tissue engineering (just a means), the device is used to apply a large amount of force that wouldn’t necessarily be possible in vitro.

What is the best bioreactor?

The human body (in vivo)

What are the key components of tissue engineering?

Cells, Scaffolds, and Biological Factors

What are the basic principles of tissue engineering?

cell isolation → cell proliferation → scaffold → construct (combining cells and scaffold) → tissue generation → transplantation (cycles)

cells

They are the building blocks of all tissues. In general groups of cells make, secrete, and organize their own support structures called extracellular matrix (e.g. IPSC and ESC)

what does SC typically stand for in tissue engineering?

(embrionic) stem cells

what does IP typically stand for in tissue engineering?

induced pluripotent (stem cells)

Scaffolds

Engineered biomaterials (e.g. collagen, silk, and ceramic) that are used for the formation of new tissues and provide structural support for cells while also facilitating things like signaling, communication, and migration of cells

biological factors

Signals that can be chemical, mechanical, and/or biological. These signals are available to cells in the local environment. Each signal will start a specific chain of response in individual cells

In order to engineer tissue, you must control the following parameters

• availability/type of growth factor (relative to quantity of cells)

• physical properties of the scaffold

• 2D vs 3D environment

• multicellular environment

• complexity of the natural environment

What kind of cells will grow on collegen?

almost any cell will grow on collagen, but its construct does not always actually replicate the desired tissue

What was the first type of tissue engineered

skin, the biggest and most easily accessible organ

In 1949, who developed cell cryopreservation at subzero temperatures?

Polge

In what year was SKIN cryopreservation developed and by whom?

Billingham developed it in 1952

What are some complexities associated with using human tissue implants?

• variability of cell growth

• process standardization

• risks assessment in clinical trials and commercialization

what are biological challenges in tissue engineering?

• cell source selection

• cell multiplication (do you have enough)

• preservation of the differentiated state

what are some engineering challenges in tissue engineering?

• biomaterial selection

• efficient usage of biomolecules

• production of functional tissue

what are some clinical challenges in tissue engineering?

• maintaining new tissue with appropriate shape and volume

• adaptation of the new tissue to the host tissue

• vascularization of the new tissue

What are xenogenic, allogeneic, and autologous cells

cells from a different species, cells from a different individual of the same species, and cells from self.

what are some of the ethical challenges associated with tissue engineering?

• privacy of donor for cell banks

• the use of xenogenic cells (issue when raising animal for this specific purpose)

• the use of human embryonic cells

• the rights of tissue donors (profit, information, privacy)

• the cost of the technology and its accessibility

What are some examples of TE applications in orthopedics?

cartilage damage repair, ligament damage repair, vertebral disc damage repair, and bone regeneration after injury

What are some examples of TE applications in skin?

burns, diabetic ulcers, plastic surgery, and venous ulcers

What are some examples of TE applications in ophthalmology?

cornea, and retina

What are some examples of TE applications in the cardiovascular field?

heart valve, myocardium patches

what are some future directions for tissue engineering?

continuous injury monitoring and 3D bioprinting

Why might every part of scaffolding need to be biocompatible?

if the material gets damaged or something is released during degradation, whatever is released must ALSO be biocompatible to avoid rejection.

the timing of the degradation profile has to match the ______ profile

regeneration

what are some requirements for biomaterials?

• biocompatible

• injectable/implantable/deliverable

• easy to synthesize/manufacture

• non-immunogenic

• have good mechanical properties

• stable over time

• resorbable/biodegradable

what are the main types of biomaterials used for scaffolds?

ceramics, synthetic polymers, and natural polymers

totipotent stem cells are…

capable of giving rise to ALL cell types and extra-embryonic tissues

pluripotent stem cells are…

capable of giving rise to all cell types

multipotent stem cells are…

capable of giving rise to all cell types of a particular tissue or organ

nullipotent stem cells are…

not capable of giving rise to other cell types

what is cell potency?

the ability of a given cell to differentiate into other cell types. the more cell types a cell can differentiate into, the greater its potency

What molecules are responsible for biological signals that play a role in controlling cell behaviors?

growth factors, chemokines, and cytokines