Cloning And Stem Cell - Biotechnology Culture and Human Values - Lecture Slides, Slides of Biotechnology

Download Cloning And Stem Cell - Biotechnology Culture and Human Values - Lecture Slides and more Slides Biotechnology in PDF only on Docsity!

1

The Eighth Asian Bioethics Conference March 19-23, 2007, Bangkok, Thailand

INTRODUCTION

The discovery of Embryonic Stem Cells (ESCs ) in the 1980s suggested therapeutic approaches to chronic, debilitating, and incurable diseases such as Parkinson’s disease, Alzheimer's, Diabetes Mellitus, and brain and spinal injuries.

Introduction (cont.)

Many areas of stem cell research and their potential clinical applications are associated with controversy; therefore there are varied socio- cultural, ethical, political, and religious viewpoints to be considered in discussions about the production and use of stem cells.

POTENTIAL APPLICATIONS

Disorder Cells transplanted Alzheimer's disease Nerve cells Atherosclerosis Endothelial cells Burns Skin cells Chronic pain Chromaffin cells Diabetes Islet cells Epilepsy Nerve cells Heart disease Cardiomyocytes Huntington's disease Nerve cells Hypocalcemia Parathyroid cells Hypocholesterolemia Hepatocytes

Disorder Cells transplanted Kidney disease Kidney cells leukemia Hematopoietic cells Liver disease Hepatocytes Macular degeneration Retinal cells Multiple sclerosis Glial cells Muscular dystrophy Skeletal muscle cells Osteoarthritis Chrondrocytes Parkinson's disease Dopaminergicneurons Rheumatoid arthritis Chrondrocytes Strokes Nerve cells Spinal cord injuries Nerve cells NATURE BIOTECHNOLOGY 1999; 17: 1173 Docsity.com 7

APPLICATIONS IN RESEARCH

 Models of human disease

 The pharmaceutical research

 Human developmental biology

 Gene therapy

STEM CELL SOURCES

10

There are various ways in which human stem cells might be obtained:

• Adult Stem Cells
• Umbilical Cords
• Placenta
• Aborted Fetuses
• Spare Embryos from IVF Clinics
• Cloned Human Embryo

EMBRYONIC STEM CELL

• Embryonic stem (ES) cells are derived from the inner cell mass of a blastocyst.
• The blastocyst forms at approximately 4 or 5 days after fertilization and contains from 64 to several hundred cells organized in an outer shell, the trophectoderm , and a collection of polarized inner cells termed the inner cell mass (ICM).

11

J Clin Invest, Vol.114, No.9, 2004, pp. 1184-

PLURIPOTENCY

Stem cells retain the ability to differentiate into cells and tissues from all 3 germ layers (endoderm, mesoderm, and ectoderm). But, these cells cannot form the other ‘extra- embryonic’ tissues necessary for complete development, such as placenta and membranes, therefore they cannot give rise to a complete new individual.

13

• • Human Reproduction, Vol.18, No.4, 2003, pp. 672-682The Journal of Urology, Vol.170, 2003, pp. 2453-

hES cells are pluripotent

Source: NIH 2001: Stem Cells: Scientific Progress and Future Research DirectionsDocsity.com^14

CLONING

An alternative method of deriving human ESCs is somatic cell nuclear transfer (SCNT), or

cloning.

16

Dolly 1997-

SCNT across species is an important challenge.

17

Removing the maternal nucleus before nuclear transfer

Nuclear transfer embryo about to be activated (Roslin Institute http://www.roslin.ac.uk)

DISADVANTAGES OF CLONING

 Not Enough Human Eggs

 Cloning damages DNA

Further improvements in SCNT protocols and in vitro culture systems are needed before contemplating the use of this technique for cell therapy.

ADULT STEM CELLS

• Stem cells have been identified in adult tissues. Examples include the brain, skeletal muscle, bone marrow and umbilical cord blood, although the heart, by contrast, contains no stem cells after birth.
• It is becoming increasingly evident that adult stem cells can show considerably more plasticity and could be more versatile than previously believed.

20

• • Cell prolif, Vol.37, 2004, pp. 23-34Proc Natl Acad Sci USA, Vol.100, 2003, pp. 1191-