Stem Cells - Microbiology - Lecture Slides, Slides of Microbiology

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STEM CELLS

ADVANCES IN SCIENCE

STEM CELL – DEFINITION

 A cell that has the

ability to

continuously divide

and differentiate

(develop) into

various other

kind(s) of

cells/tissues

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STEM CELL HISTORY

 1998 - Researchers first extract stem cells from human embryos

 1999 - First Successful human transplant of insulin-making cells from cadavers

 2001 - President Bush restricts federal funding for embryonic stem- cell research

 2002 - Juvenile Diabetes Research Foundation International creates $20 million fund-raising effort to support stem-cell research

 2003?? - California ok stem cell research

 2004 - Harvard researchers grow stem cells from embryos using private funding

 2004 - Ballot measure for $3 Billion bond for stem cells

HISTORY OF HUMAN EMBRYONIC

STEM CELL RESEARCH

In 1998, James Thomson (University of Wisconsin-Madison) isolated cells from the inner cell mass of the blastocyst, and developed the first human embryonic stem cell line in culture.

Isolate inner cell mass

Culture cells

Inner cell mass (forms fetus)

Day 5- Blastocyst

WHAT ARE STEM CELLS?

Stem cells are the raw

material from which all of

the body’s mature,

differentiated cells are

made. Stem cells give

rise to brain cells, nerve

cells, heart cells,

pancreatic cells, etc.

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MAJOR TYPES OF STEM CELLS

Embryonic Stem Cells

• Totipotent : cell can develop into all cell types
• “Immortal”: can self- renew indefinitely
• Plentiful

Adult Stem Cells

• Multipotent: cell can develop into a few cell types but not all
• Located in few organs or may be unidentified
• Hard to find

ONE CELL - SEVERAL LINEAGES

EMBRYOGENESIS AND

DIFFERENTIATION

 Specific regions of the embryo give

rise to the specific organ systems

 Ectoderm generates the outer layer of the embryo and produces the surface layer (epidermis) of the skin and forms the nerves  Endoderm becomes the innermost layer of the embryo and produces the digestive tube and its associated organs (including the lungs)  Mesoderm becomes sandwiched between the ectoderm and endoderm and generates the blood, heart, kidney, gonads, bones, and connective tissues. 11

EARLY HUMAN DEVELOPMENT

AN OVERVIEW OF EARLY DEVELOPMENT MODELED WITH PLAY-DOUGH Fertilized egg

Totipotent stem cells

Totipotent: Can become any cell in body or placenta

Fate Decision Pluripotent stem cells (3-5 days old)

Blastocyst

Pluripotent: Can become any cell in body

Implantation

Fate Decision

Gastrulation (day 14) leads to Primary Germ Cells Endoderm (inner) Mesoderm (middle)digestive tract, resp. trackbones, blood cells, heart Ectoderm (outer)skin, CNS

Multipotent: Can become any cell within a specific germ layer or cell lineage Embryonic stem cells come from inner cell mass of blastocyst.

Implantation

Fate Decision

Gastrulation (day 14) leads to Primary Germ Cells Endoderm (inner) Mesoderm (middle)digestive tract, resp. trackbones, blood cells, heart Ectoderm (outer)skin, CNS

Multipotent: Can become any cell within a specific germ layer or cell lineage

Multipotent

BONE MARROW STEM CELLS

HOW TO DERIVE AN EMBRYONIC STEM CELL LINE?

Inner cell mass

Day 5- Blastocyst

Isolate inner cell mass (destroys embryo) ETHICS?

Culture cells

A stem cell line is composed of a population of cells that can replicate themselves for long periods of time in vitro (out of the body) (^) An embryonic stem cell clone Docsity.com^17

EMBRYONIC STEM (ES) CELLS

 ES cells are

found at the blastocyst stage, four to five days after the union of the sperm and egg, before the embryo implants in the uterus. (^19)

ES CELLS ARE "PLURIPOTENT" - I.E. CAPABLE OF

FORMING EMBRYONIC TISSUES