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From Stem Cells to Beta Cells: Possible Cure for Diabetes Mellitus By Ryan Scavinski
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Diabetes Mellitus Type 1 Diabetes is caused by the autoimmune destruction of β-cells within the pancreas. Type 1 Diabetes is caused by the autoimmune destruction of β-cells within the pancreas. No β-cells, no insulin No β-cells, no insulin Diabetics need to monitor blood glucose and control it with insulin. Diabetics need to monitor blood glucose and control it with insulin.
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Past Treatments Transplantation of pancreatic islet cells Transplantation of pancreatic islet cells Problems Problems –Patient requires more than 600 islets/kg body weight = two deceased organ donors –Immunological rejection
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Using Stem Cells Two approaches used to differentiate Embryonic Stem Cells into β-cells or Insulin Producing Cells (IPCs) Two approaches used to differentiate Embryonic Stem Cells into β-cells or Insulin Producing Cells (IPCs) –Embryoid Body Formation –Definitive Endoderm Formation
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Embryoid Body Formation An embryoid is the arrangement of stem cells destined to differentiate into the ectoderm, mesoderm and endoderm. An embryoid is the arrangement of stem cells destined to differentiate into the ectoderm, mesoderm and endoderm. With multiple treatment of growth factors, Embryonic stem cells give rise to Nestin cells, which in turn differentiate into IPCs. With multiple treatment of growth factors, Embryonic stem cells give rise to Nestin cells, which in turn differentiate into IPCs.
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Problems Low efficiency for producing IPCs Low efficiency for producing IPCs Also showed development of tumors in the kidney and spleen in some transplanted mice. Also showed development of tumors in the kidney and spleen in some transplanted mice.
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Definitive Endoderm Approach This approach bypasses the Embryoid formation and generates the endoderm, in which produce the cells needed for insulin production. This approach bypasses the Embryoid formation and generates the endoderm, in which produce the cells needed for insulin production.
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Differentiation Steps 1. ESCs were placed onto a culture dish with a chemically defined medium (CDM) containing 50 ng/mL Activin A for 4 days 1. ESCs were placed onto a culture dish with a chemically defined medium (CDM) containing 50 ng/mL Activin A for 4 days
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With and without Activin A With and without Activin A PCR of expression of endoderm genes PCR of expression of endoderm genes –Gapd, sox17, pdx1, hlxb9, hnf4a and insulin gapd sox17 pdx1 hlxb9 hnf4α insulin
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continued 2. Then the cells were transferred onto a CDM with 10 -6 M Retinoic acid (RA) for another 4 days 2. Then the cells were transferred onto a CDM with 10 -6 M Retinoic acid (RA) for another 4 days
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Without Activin A and RA With Activin A and RA small clusters of differentiated ES
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PCR A+/RA+ A-/RA- A+/RA- A-/RA+ gapd sox17 pdx1 hlxb9 hnf4α insulin
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continued 3. Then the CDM was changed to modified islet maturation medium containing bFGF- a pancreatic cell maturation factor for 3 days 3. Then the CDM was changed to modified islet maturation medium containing bFGF- a pancreatic cell maturation factor for 3 days 4. Finally the differentiated cells were switched to a islet maturation medium containing nicotinamide and the bFGF for another 3 days. 4. Finally the differentiated cells were switched to a islet maturation medium containing nicotinamide and the bFGF for another 3 days.
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In this final stage, many differentiated cells formed spherical clusters In this final stage, many differentiated cells formed spherical clusters Also expressed the pancreatic β cell markers such as pdx1, INSULIN, glucokinase and glut2 shown in PCR Also expressed the pancreatic β cell markers such as pdx1, INSULIN, glucokinase and glut2 shown in PCR
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Differentiated Embryonic Stem Cells gapd sox17 pdx1 hlxb9 hnf4α insulin glut2 Amy SST Sur1 GCG GCK Maturation Control
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To test cells for insulin release, cells were incubated in buffer containing 2.5 mM glucose for 15 min To test cells for insulin release, cells were incubated in buffer containing 2.5 mM glucose for 15 min Then incubated with 27.5 mM glucose for another 15 min Then incubated with 27.5 mM glucose for another 15 min Tested for insulin release with a Rat/Mouse insulin ELISA Tested for insulin release with a Rat/Mouse insulin ELISA
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Insulin secretion (ng/mg) Suspension Adhesion 2.5 mM 27.5 mM
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Transplantation Differentiated cells were transplanted under the renal capsule (kidney) of diabetic mice. Differentiated cells were transplanted under the renal capsule (kidney) of diabetic mice. 30% showed normal blood glucose levels for 6 weeks 30% showed normal blood glucose levels for 6 weeks They removed the cell transplanted kidney-mice regained hyperglycemia They removed the cell transplanted kidney-mice regained hyperglycemia
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0 7 14 21 28 35 42 49 56 Days after transplantation 30 25 20 15 10 5 0 Blood glucose (mM)
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Results and Discussion The combination of Activin A and Retinoic Acid is an effective method to induce Embryonic Stem Cells to differentiate into insulin producing cells The combination of Activin A and Retinoic Acid is an effective method to induce Embryonic Stem Cells to differentiate into insulin producing cells Further research in needed to see if the difference between human and mouse will impair the function of transplanted ESC derived cells Further research in needed to see if the difference between human and mouse will impair the function of transplanted ESC derived cells
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My Opinion
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Reference: Reference: Soria, B., Skoudy, A., and Martin, F. 2001. From stem cells to beta cells: new strategies in cell therapy of diabetes mellitus. Diabetologia 44 407-415 Soria, B., Skoudy, A., and Martin, F. 2001. From stem cells to beta cells: new strategies in cell therapy of diabetes mellitus. Diabetologia 44 407-415 Raikwar, S. and Zavazava, N. 2009. Insulin producing cells derived from embryonic stem cells: are we there yet?. Journal of Cellular Physiology, 218 256-263 Raikwar, S. and Zavazava, N. 2009. Insulin producing cells derived from embryonic stem cells: are we there yet?. Journal of Cellular Physiology, 218 256-263 Jiang, W., Shi, Y., Zhao, D., Chen, S., Youg, J., Zhang, J., Qing, T., Sun, X., Zhang, P., Ding, M., Li, D., and Deng, H. 2007. In vitro derivation of functional insulin producing cells from human embryonic stem cells. Cell Research. 17 333-344 Jiang, W., Shi, Y., Zhao, D., Chen, S., Youg, J., Zhang, J., Qing, T., Sun, X., Zhang, P., Ding, M., Li, D., and Deng, H. 2007. In vitro derivation of functional insulin producing cells from human embryonic stem cells. Cell Research. 17 333-344
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