stem cells and plastic surgery
DESCRIPTION
Dr. Kenneth Dickie from Royal Centre of Plastic Surgery in Barrie, Ontario explained the use of stem cells technology in plastic surgery. If you have any questions, please contact Dr. Kenneth Dickie at http://royalcentreofplasticsurgery.com/TRANSCRIPT
Stem Cells and Plastic Surgery
Dr. Kenneth DickieRoyal Centre of Plastic Surgery
Stem cell Plasticity and Cloning
Why are these topics suddenly so prevalent?What are key issues relating to stem cell use in
Medicine
Mature Tissues
Stem Cell
How are stem cells How are stem cells defined?defined?
Differentiation and Commitment
1) Self-renewal
2) Multi-potential
3) Highly proliferative
Key Issues:
• There are many different types of stem cells-an important distinction: Embryonic vs. Adult
• Embryonic stem cells are derived from an egg shortly after it begins to grow, and are totipotent-able to generate any tissue in the body
• Adult stem cells are found in many different tissues in the body, and appear to have more restricted and specialized functions
Key Issues:
• New research in the field of “stem cell plasticity” has suggested that adult stem cells may have greater regenerative potential than was previously suspected
Embryonic stem cells: Isolated from human tissue(1998)
Derivation of Embryonic Stem Cells
Totipotent ES Cells
The generation of federally approved human ES cell lines was all done in test tubes from eggs collected from human donors, salvaged from cryobanks.
The National Bioethics Advisory Commission recommended only using human ova left over from in vitro fertilization procedures.
It was from these otherwise discarded cells that the 64 human ES cell lines were generated which were ultimately approved by the
Bush Administration.
From these lines, only 8 are dividing continually and are available for use in the investigation into their potential to be used in
regenerative medicine (not currently studied at Wash U).
It is not known yet if they will be better, be able to repair more tissues, or live longer than stem cells from adult sources. More
comparisons are needed.
• Federally approved stem cell lines are derived from discarded eggs from fertility clinics.
• Federally approved stem cell lines are derived from discarded eggs from fertility clinics.
Will human cloning be used to create new people?Will human cloning be used to create new people?
Cloning human stem cells is beingStudied to learn how to regeneratea patient’s own damaged tissuesand organs, without the possibilityof rejection by the immune system.
NO!
Combining cloning with the use of Combining cloning with the use of embryonic stem cellsembryonic stem cells
Egg Cell
Healthy Adult Cell: nuclear material “matches” the patients; no rejection
Generate humanEmbryonic stem cellswithout using sperm
Spinal cord injured patient
RegenerativeTherapy
Nuclear transfer is done with a finely drawn glass pipette. Nuclei are shown in the pipette, ready to be injected into the recipient egg.
Do we have to interfere with human development?
Stem cells also exist in many adult tissues
Embryonic Stem cells
Adult Stem Cells found in:Bone marrow
BrainLiver
PancreasSkin
MuscleIntestine
& other organs
Embryonic stem cells: Isolated from human eggs after in vitro fertilization OR donation of nuclear material from an already differentiated adult cell (cloning)
Characteristics of Adult Stem Cells
• Found in discreet anatomical sites in many major organ systems
• Typically, restricted in potential to the organ of residence (i.e. brain stem cells only make brain tissue, marrow stem cells make blood, etc.)
• In many cases, most readily evident as a reservoir of tissue for repair functions.
• Some studies have SUGGESTED that adult stem cells may be able to contribute to the repair of liver, brain, muscle, and other tissues.
Adult stem cells exist for many different human organs - can they serve as an alternative to embryonic stem cells?
Current use of adult stem cells:• Bone marrow transplantation
Potential uses of adult stem cells:• Brain and spinal cord injury and disease.• Repair of heart tissue.• Regeneration of liver tissue.• Diabetes therapy - pancreas repair.• Repair of muscle, blood vessels, and skin
(potential therapies for burn victims)• And many other possibilities……..
HSCBLOOD
VASCULAR STEM CELLS
HEPATIC STEM CELLS
MUSCLESTEM
CELLS
NEURAL STEM CELLSMESENCHYMAL
STEM CELLS
FAT
CARTILAGE
MUSCLE
CARDIACAND
SKELETAL
BONE
FIBRO-BLAST
NEURONS
WHOLEMOUSE
LIVER
?
?
MESENCHYMAL STEM CELLS
FAT
CARTILAGE
MUSCLE
CARDIAC AND
SKELETAL
BONE
FIBRO-BLAST
NEURONS??
??
Phenotype of the most primitive MSC populations?Phenotype of the most primitive MSC populations?
Trafficking properties in vivo? In response to injury?Trafficking properties in vivo? In response to injury?
Bone Bone marrowmarrow
Adipose Adipose TissueTissue
Adipose-derived mesenchymal stem cell
(AMSC)
Fat
Bone Cartilage
Muscle
Generation of Adipose-derived MSC (AMSC)
Isolation procedure:
• Take a bucket to the OR; collect fat excised during liposuction (LA) or gastric bypass (St Louis)
• Dissect away visible vessels and mince• Collagenase digest and separate by density centrifugation• +/- HSC removal• Defined initially by plastic adherence and rapid growth in
minimal mediuum• Easily transduced and very proliferative
• Collaborators: De Ugarte and Hedrick: UCLAChris Eagon, Wash U. St Louis
Neo-organoid (new tissue) created from adipose – derived adult stem cells seeded
onto a biodegradable matrix
Neo-organoid (new tissue) created from adipose – derived adult stem cells seeded
onto a biodegradable matrix
• The tissue was created by implanting human AMSC on the matrix into a laboratory strain of mice that have no immune system. It is the size of a dime.
• Matrix is very well tolerated, non-immunogenic, and permissive for neo-vascularization and systemic protein delivery.
• These organoids are currently being used to deliver therapeutic drugs and proteins such as clotting factors needed in hemophiliacs, and their potential to form specific tissues such as a new pancreas for diabetic patients.
Adipose Derived Stem Cells
• Recent research has shown that stem cells from fat have the ability to regenerate nerve tissue, strengthen damaged heart tissue, heal intestinal fistulas in Crohn’s Disease, and may be able to be used as a building block to cosmetically enhance the female breast.
Adipose derived stem cells
• Clinical evidence that traumatic scars can be eliminated following stem cell grafting into the scarred region
• If cutaneous scars can be recognized, and eliminated by stem cells, the same should be true for cutaneous tumors such as Basal Cell carcinoma, Squamous Cell carcinoma, and Malignant Melanoma.
There are more urgent needs for stem cells:
Stem Cells and Autogenous Skin Grafts
Skin Grafting of Burn Wounds
Post burn mortality and morbidity:
What if fat from every burn patient could be immediately harvested at the time of admission, and sent to the tissue lab for isolation and growth of the patients stem cells.
Under the appropriate chemical stimulation, autogenous skin would be available for skin grafting by the time the patients burns have been stabilized.
Post Burn Mortality and Morbidity:
• Cord blood banked stem cells due not possess immune competence, thus , tissue banks could continue to grow, and store tissues of varying types (bone, cartilage, fascia, tendon, skin) which would be immediately available for treatment of deformities which are either post traumatic, or post tumor resection-where immediate reconstruction is mandatory.
Bone Regeneration: Mesenchymal stem cells (MSC)Bone Regeneration: Mesenchymal stem cells (MSC)
MSCs repair large gaps in bones in 32 weeks
No evidence of immune rejection following implantation
of MSC from an unrelated donor
MSCs repair large gaps in bones in 32 weeks
No evidence of immune rejection following implantation
of MSC from an unrelated donor
Phase 2 clinical trials for large cranio-facial and long bone defects began in 2002
in Europe and US
Phase 2 clinical trials for large cranio-facial and long bone defects began in 2002
in Europe and US
ControlControl MSC treatedMSC treated
MSCs protect cartilage and boneMSCs protect cartilage and bone
Phase 1 clinical trial began in 2002 in Europe and US
Phase 1 clinical trial began in 2002 in Europe and US
Meniscal Repair - Cartilage ProtectionMeniscal Repair - Cartilage Protection
Complete menisectomyComplete menisectomy Partial menisectomyPartial menisectomy
goat model
•Experimental data suggests that adipose
derived stem cells have the ability to lodge in a variety of tissue types following a variety of
routes of administration•In models of acute local injury , these cells appear to preferentially home to,
or accumulate in, the damaged tissue
•The mechanism of recruitment of adult stem cells to sites of injury or
disease is a cell-mediated response
What is the Physicians responsibility?
• When medical breakthroughs have the potential to improve the mental, social or physical wellbeing of our patients, we as physicians , should exert our influence and knowledge such that these breakthroughs do not linger in “no mans land” while the politics are still being debated.
If you have any questions, feel free to contact Dr. Kenneth Dickie at royalcentreofplasticsurgery.com
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