1. An Introduction to Tissue Engineering
Cindy Handley, PhD, MT(ASCP)
SCCC Biology Instructor

2. Acknowledgements: Pittsburgh Tissue Engineering Initiative
a network strategy to promote regional economic growth
through the advancement and creation of biomedical and related
technologies associated with engineered tissues, Including cell culturing,
gene therapy, organ transplantation and regeneration, biomaterials,
and computer-assisted analysis and design.
Mark Krotec, BS, MS
facilitator for the summer teachers’ workshop and major
contributor of data for this presentation via the Education Outreach
Manual in Tissue Engineering and the summer workshop.

3. Overview
Tissue engineering defined
Stem cell research
Tissue model constructs
and lab techniques
IV. Ethics

4. Tissue Engineering Defined

5. According to the Pittsburgh Tissue Engineering Initiative,
“Tissue engineering is an emerging
interdisciplinary field that applies
the principles of biology and
engineering to the development of
viable substitutes that restore,
maintain, or improve the function of
human tissues.”

6. What are ‘viable substitutes’?
On a large scale, certain surgical interventions, like castration of a bull, have led to alteration of tissue function.
On a molecular level, gene therapy is has been very successful with plants and animals
On a cellular level, the research is currently focused on stem cells.

7. Stem cells
According to the Merriam-Webster Online Dictionary, a stem cell is,
“an unspecialized cell that gives rise to differentiated cells“
Two basic types:
Embryonic – pluripotential
Adult – multipotential

8. Embryonic stem cells
According to Richard Mollard, Ph.D., of the International Society for Stem Cell Research, “Human embryonic stem (ES) cells are cultured cell lines derived from the inner cell mass of the blastocyst that can be grown indefinitely in their undifferentiated state, yet also are capable of differentiating into all cells of the adult body.”

10. Animation: Stem cells

11. Embryonic stem cells (con’t)
Two sources
Fertilized egg from in vitro fertilization
Ovum that has had nucleus removed and nuclear material injected from intended recipient of final tissue product
(reproductive/therapeutic cloning)
Very controversial

12. Adult stem cells Found in: Umbilical cord blood/tissue
Adult brain, blood cornea, retina, heart, fat, skin, dental pulp, bone marrow, blood vessels, skeletal muscle and intestines

14. II. Stem cell research

15. What progress has been made to date?
Autologous stem cells have been injected into heart to regenerate damaged cardiac tissue
Corneal autologous stem cell grafts have been used to treat eye disease & trauma
Skin replacement has been grown with stem cells for transplant in burn victims

16. Progress…
Autologous stem-cell cartilage grafts have been used to treat joint disease
Leukemia & other cancers have been treated with stem cells from bone marrow and umbilical cord blood
A human mandible has been produced using a titanium mesh and autologous bone-marrow stem cells

17. The future? According to the Stem Cell Research Center:
Half Of All Americans Could Benefit From Stem Cell Research
Experts are predicting that stem cell research has the potential
to help up to half of all Americans, who suffer from some form of
presently incurable disease, injury or birth defect. Some of
Those conditions include: One million children with juvenile diabetes
8.2 million people with cancer
58 million with heart disease
Four million suffering from Alzheimer's disease
10 million with osteoporosis
43 million arthritis sufferers
250,000 people paralyzed by spinal cord injuries
30,000 victims of Lou Gehrig's disease
500,000 with Parkinson's disease

18. III. Tissue model constructs & lab techniques

19. Tissue engineering requires three things:
Cells
Signals
Scaffold

20. We’ve already discussed different types of cells that may be used
The scaffold refers to the matrix within the tissue model construct
The signals refer to molecular signaling molecules, also known as growth factors

21. Basic scaffold criteria:
Portions need to be biodegradable
Usually designed in the shape of the tissue product the researcher is working on

22. www.eng.nus.edu.sg/ EResnews/0210/rd/rd_10.html

23. Biomimetic Scaffold Fabrication
                                                                                                                                       
bms.dent.umich.edu/research/malab.html

24. www. millenium-biologix. com/Html/00_ScientificInformationCartiGraft
Autologous de novo cartilage formed on Skelite™ tissue engineering scaffold
(grown in vitro), illustrating the configuration of the implant that provides
functional cartilage tissue at the articular surface. The presence of functional
cartilage tissue represents a major advance over current cell therapy techniques.
Cell therapy involves the implantation of cells that still have to make new cartilage
in vivo at the defect site under very challenging conditions. The histology image
on the right shows that cells are healthy and growing, while attaching themselves
to the Skelite™ and beginning to differentiate into mature cartilage.

25. V. Ethics

26. Now that we see that we CAN,
the question is…
should we??????

27. ETHICS
The great divide over stem cells (
The Ethics of Human Embryonic Stem Cell Research (
Research Ethics and Stem Cells (stemcells.nih.gov/info/ethics.asp)

28. Ethics (con’t)
Stem Cell Research: All sides to the dispute (
Guidelines for Human Embryonic Stem Cell Research (

29. Tissue engineering defined Stem cell research Tissue model constructs
SUMMARY
Tissue engineering defined
Stem cell research
Tissue model constructs
and lab techniques
IV. Ethics

30. Selected References Cited
Armon, C. (2005) Medscape Neurology & Neurosurgery 7(1), Retrieved September 18, 2005, from
Bhatia, R., & Hare, J. (2005). Mesenchymal Stem Cells: Future Source for Reparative Medicine [Electronic version]. Congestive Heart Failure, 11(2),
Carmichael, Mary. (2005). Organs under construction. Newsweek, Summer 2005,
Lanza, R., & Rosenthal, N. (2004). The Stem Cell Challenge. Scientific American, June 2004,
Pittsburgh Tissue Engineering Initiative (2001). An Education Outreach manual in Tissue Engineering, updated through June Pittsburg, PA, PTEI: Author.
Weiss, R. (2005). The power to divide. National Geographic. July 2005, 3-27.

31. The End