If starfish can grow a new arm,

why can’t I?

STEM CELL

• INTRODUCTION• MAINTENANCE

OF STEM CELL

SUE ®

WHERE DO I COME FROM?

GAMETES

FERTILISATION

ZYGOTE WHEN GAMETE FUSED

MORULA

BLASTOCYSTS

IMPLANTATION

EMBRYO IMPLANTED ZYGOTE TO 8TH WEEK

FETUS

HOW DOES A ONE CELL ZYGOTE

BECOME A HUMAN?Human body composed of 50-75 TRILLION cells.MORE THAN 220 TYPES OF CELL

DIFFERENTIATION GROWTH FACTORS INTRACELLULAR SIGNALLING GENETIC MATERIAL

- TO BE CONTINUED IN NEXT PART

STEM CELLAscending stalk of a treeAlso means 'to stop or to slow

down’

In this case, stop and slow down and turn into other types of cells.

DIFFERENCE OF STEM CELL AND NORMAL BODY CELLS Ability to divide throughout life

(theoretically) Ability to differentiate into many

different cell types

TYPES OF STEM CELL EMBRYONIC STEM CELL FETAL STEM CELL BERASHI CELL ADULT STEM CELL

POTENTIAL OF STEM CELLTotipotent stem cells

early embryos Each cell can form a complete organism

Pluripotent stem cells undifferentiated inner cell mass of blastocyst form any of over 200 different cell types

Multipotent stem cells ability to differentiate is more limited

TOTIPOTENT STEM CELLS Up to 8-cell stage of zygote No research work on totipotent stem

cells Our aim is NOT to create a clone human

EMBRYONIC STEM CELLS Derived from inner cell mass of

blastocysts Pluripotent

1. Ectoderm2. Mesoderm3. Endoderm

Able to replicate indefinitely

BLASTOCYSTS

ISOLATION OF EMBRYONIC STEM CELLS SOURCE

• SURPLUS EMBRYO – I.V. FERTILISATION TECHNIQUE OF ISOLATION

• MICROSURGERY• LASER-ASSISTED BLASTOCYST

DISSECTION

MAINTENANCE OF EMBRYONIC STEM CELLS STEM CELL NICHE- in vivo or in vitro stem cell microenvironment Human ES cells are often grown in - fibroblastic growth factor-2 containing, fetal bovine

serum supplemented media Grown on a feeder layer of cells- supportive in maintaining the pluripotent

characteristics of embryonic stem cells

GERM LINE STEM CELLS NICHE

HEMATOPOETIC STEM CELLS NICHE

AGING OF STEM CELLS Occurs when cultured in vitro Morphology is changed and their

proliferative capacity is decreased Causes:

1. reduction in niche signaling pathway activity

2. accumulation of Reactive Oxygen species (ROS)

BERASHI STEM CELLS Found in cord and extra embryonic

tissues and membranes Formed only by TOTIPOTENT CELLS Umbilical cord banking

FETAL STEM CELLS Taken from aborted fetal tissue Have the potential to be a greater kind

of cells that adult cells

ADULT STEM CELLS

Hematopoietic stem cells Intestinal stem cells Mesenchymal stem cells Endothelial stem cells Neural stem cells Olfactory adult stem cells Testicular cells Mammary stem cells

HISTORY OF STEM CELL RESEARCH

REGENERATIVE MEDICINE process of replacing or regenerating human

cells, tissues or organs to restore or establish normal function

grow tissues and organs in the laboratory and safely implant them when the body cannot heal itself

Advantages:1. solve the problem of the shortage of organs available

for donation2. solve the problem of organ transplant rejection

DEDIFFERENTIATION

CHALLENGES OF STEM CELL CHALLENGES OF STEM CELL RESEARCHRESEARCH If the embryo = inanimate matter

-then the resistance to embryonicstem cell research is ludicrous.

If the embryo is alive, then embryonic stem cell research is immoral.

one must differentiate between human beings and persons.