FALL 2015
Special topics in BE
Tissue Engineering - Defined
Jasmin Šutković
7th Dec.2015
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.”
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.
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
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.”
http://www.time.com/time/2001/stemcells/#
• Animation: Stem cells
http://www.dnalc.org/stemcells.html
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
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
Stem cell research
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
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
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
www.stemcellresearchfoundation.org/WhatsNew/Benefit.htm
Tissue model
constructs &
lab techniques
Tissue engineering requires three things:
Cells
Scaffold
Signals
• 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
Basic scaffold criteria:
• Portions need to be biodegradable
• Usually designed in the shape of the
tissue product the researcher is
working on
www.eng.nus.edu.sg/ EResnews/0210/rd/rd_10.html
Biomimetic Scaffold Fabrication
bms.dent.umich.edu/research/malab.html
www.millenium-biologix.com/Html/00_ScientificInformationCartiGraft.htm
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.
Ethics
Now that we see that we CAN,
the question is…
should we??????
ETHICS
• The great divide over stem cells
(www.mtulode.com/index.php?issuedate=
&section=12&artid=4540)
• The Ethics of Human Embryonic
Stem Cell Research
(www.isscr.org/public/ethics.htm)
• Research Ethics and Stem Cells
(stemcells.nih.gov/info/ethics.asp)
Ethics
(con’t)
• Stem Cell Research: All sides to the
dispute
(www.religioustolerance.org/res_ste
m.htm)
• Guidelines for Human Embryonic
Stem Cell Research
(www.iom.edu/report.asp?id=26661)
SUMMARY
I. Tissue engineering defined
II. Stem cell research
III. Tissue model constructs
and lab techniques
IV. Ethics
Selected References Cited
Armon, C. (2005) Medscape Neurology & Neurosurgery 7(1), 2005. Retrieved September
18, 2005, from http://www.medscape.com/viewarticle/496732
Bhatia, R., & Hare, J. (2005). Mesenchymal Stem Cells: Future Source for Reparative
Medicine [Electronic version]. Congestive Heart Failure, 11(2), 87-91.
Carmichael, Mary. (2005). Organs under construction. Newsweek, Summer 2005, 46-48.
Lanza, R., & Rosenthal, N. (2004). The Stem Cell Challenge. Scientific American, June
2004, 93-99.
Pittsburgh Tissue Engineering Initiative (2001). An Education Outreach manual in Tissue
Engineering, updated through June 2005. Pittsburg, PA, PTEI: Author.
Weiss, R. (2005). The power to divide. National Geographic. July 2005, 3-27.