1 Stem Cells: Scientific Potential and Alternatives
2 Review of Terminology DNA -Gene - functional unit of heredity, a segment of DNA located at a specific site on a chromosome; genes direct the formation of proteins. Nucleus – Cell - the basic unit of life, all living organisms are made up of cells somatic cell - germ cell -
3 Differentiation of Human TissuesEarly embryonic cells unspecialized Three primary tissue layers: All tissues develop from here
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5 Adult Stem Cells Stem cells = cells that have the ability to divide for indefinite periods and Remember: Progenitor cells = partially specialized cells that can give rise
6 Stem Cells of the Bone Marrow
7 The Problem of Cell PotencyMultipotent – Pluripotent – Totipotent -
8 Derivation of hES Cells“Excess” frozen blastocysts donated from fertility clinics Inner cell mass (embryo) separated from trophoblast (placenta) Cells dissociated and cultured in laboratory Can be made to differentiate using chemical signals
9 Blastocyst Diagram
10 Dr. Hariom Yadav 12/4/2017
11 Dr. Hariom Yadav 12/4/2017
12 Dr. Hariom Yadav 12/4/2017
13 Applications of Pluripotent Stem Cells“decision-making genes” (birth defects, cancer) human cell lines for all cell types replacement tissue for degenerative conditions (Parkinson’s and Alzheimer’s disease, diabetes, heart disease, stroke, arthritis)
14 Example: Diabetes Insufficient insulin production inInsulin needed for “ ” cells derived from stem cells produce insulin Eliminates need for insulin injections
15 Scientific Challenges RemainingUnderstanding of cellular events that lead to and - Can stem cells be modified to minimize tissue incompatibility? Time of development and expense of treatments
16 Rejection: Possible SolutionsGenetic engineering Somatic cell nuclear transfer ( ) develops into a Dolly the sheep
17 Alternatives to hES CellsUmbilical cord blood Contains and stem cells (lower potency than hES) Patient specific Cord blood banks $2000 collection and $125/year storage fees Some public banks for donated cells
18 Alternatives to hES CellsInduced Pluripotent Stem Cells (iPS)
19 Alternatives to hES CellsInduced Pluripotent Stem Cells (iPS) Show potency than cord cells Low efficiency (recent improvements) Other problems
20 Alternatives to hES CellsDirect Cell Reprogramming Turns one cell (ex. Skin cell Neuron) Uses RNA, no virus DNA needed Eliminates need for Potential and problems are uncertain
21 Autologous Stem Cell TherapiesSelf-donation of Injected (with or without chemical treatment) into Not FDA approved Clinical trials underway (heart attack, spinal cord injury, etc.) Many Americans seek overseas options
22 Questions? The United States has been criticized by some for being too restrictive to stem cell-based research and therapies. Should U.S. laws be relaxed to be more accommodating to those wishing treatment? A recent study by Duke University predicted that by the year 2050, regenerative procedures based on stem cell and other biotechnologies could extend an average human life span by up to 100 years. Is this a desirable goal? Many biotechnologies are vastly expensive, yet much of the basic research supporting these developments is paid for by taxpayers. Who should benefit?