From stem cells to beta cells possible cure for diabetes mellitus
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From Stem Cells to Beta Cells: Possible Cure for Diabetes Mellitus. By Ryan Scavinski. Diabetes Mellitus. Type 1 Diabetes is caused by the autoimmune destruction of β -cells within the pancreas. No β -cells, no insulin Diabetics need to monitor blood glucose and control it with insulin.

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From Stem Cells to Beta Cells: Possible Cure for Diabetes Mellitus

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From Stem Cells to Beta Cells: Possible Cure for Diabetes Mellitus

By Ryan Scavinski


Diabetes Mellitus

  • Type 1 Diabetes is caused by the autoimmune destruction of β-cells within the pancreas.

  • No β-cells, no insulin

  • Diabetics need to monitor blood glucose and control it with insulin.


Past Treatments

  • Transplantation of pancreatic islet cells

  • Problems

    • Patient requires more than 600 islets/kg body weight = two deceased organ donors

    • Immunological rejection


Using Stem Cells

  • Two approaches used to differentiate Embryonic Stem Cells into β-cells or Insulin Producing Cells (IPCs)

    • Embryoid Body Formation

    • Definitive Endoderm Formation


Embryoid Body Formation

  • 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.


Problems

  • Low efficiency for producing IPCs

  • Also showed development of tumors in the kidney and spleen in some transplanted mice.


Definitive Endoderm Approach

  • This approach bypasses the Embryoid formation and generates the endoderm, in which produce the cells needed for insulin production.


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


  • With and without Activin A

  • PCR of expression of endoderm genes

    • Gapd, sox17, pdx1, hlxb9, hnf4a and insulin

gapd sox17 pdx1 hlxb9 hnf4α insulin


continued

  • 2. Then the cells were transferred onto a CDM with 10-6 M Retinoic acid (RA) for another 4 days


Without Activin A and RA

With Activin A and RA

small clusters of differentiated ES


PCR

  • A+/RA+

  • A-/RA-

  • A+/RA-

  • A-/RA+

gapd sox17 pdx1 hlxb9 hnf4α insulin


continued

  • 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.


  • 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


Differentiated Embryonic Stem Cells

gapd sox17 pdx1 hlxb9 hnf4α insulin glut2 Amy SST Sur1 GCG GCK

Maturation

Control


  • 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

  • Tested for insulin release with a Rat/Mouse insulin ELISA


2.5 mM

27.5 mM

Insulin secretion (ng/mg)

Suspension Adhesion


Transplantation

  • Differentiated cells were transplanted under the renal capsule (kidney) of diabetic mice.

  • 30% showed normal blood glucose levels for 6 weeks

  • They removed the cell transplanted kidney-mice regained hyperglycemia


30

25

20

15

10

5

0

Blood glucose (mM)

0 7 14 21 28 35 42 49 56

Days after transplantation


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

  • Further research in needed to see if the difference between human and mouse will impair the function of transplanted ESC derived cells


My Opinion


  • 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

  • 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


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