Cloning and Stem Cell Transfer

8/2/2019 Cloning and Stem Cell Transfer

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K THENNARASI

KMC


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WHAT IS HUMAN CLONE ?HUMAN EMBRYO CLONE means

a human embryo that is a geneticcopy of another living or deadhuman but does not include a

human embryo created by thefertilisation of a human egg byhuman sperm.


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WHY HUMAN CLONING? To extract Embryonic Stem Cells

To cure diseases To develop Assisted

Reproductive techniques

To research stemcell ,

embryo development


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NORMAL FERTILISATION vs

CLONING

Method 1: Usual reproduction [in utero or in vitro]

Method 2: Somatic Cell Nuclear Transfer [SCNT]


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TYPES OF CLONINGEMBRYO CLONING

REPRODUCTIVE CLONING

THERAPEUTIC CLONING


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EMBRYO CLONING Produce monozygotic twins or triplets

From fertilised embryo

Remove one or more cells

Encourage to develop into one embryo


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Newly formed embryo containing DNA from somatic cell

cell division

implant

(Diploid )


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Removal of nucleus from adult cell

(Irving Weissman,2002)


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Transfer of nucleus to enucleatedoocyte

(Irving Weissman,2002)


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Nuclear transfer

Nuclear transfer embryo about to be activated

(Roslin Institute http://www.roslin.ac.uk/library/)


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REPRODUCTIVE CLONINGProduce a duplicate of existing

animal

Used to clone mammals

May produce genetic defects

Medical ethicist- immoral procedureand unsafe


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THERAPEUTIC CLONING DNA extracted from a human cell

Inserted into a womans ovum

Develop and produce stem cells Stem cells are removed from pre-embryo

Grown into specific organ

Transplanted into the patient


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THERAPEUTIC CLONING -

TARGETED DISEASES Diabetes mellitus (juvenile

form)

Spinal cord injury Parkinsons disease

Stroke

Amyotropic lateral sclerosis

Myocardial infarction

Congestive cardiac failure


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PROBLEMS WITH CLONINGUsually fails[ require many oocytes]

Faulty genetic reprogramming of cells

[Born clones have obvious or subtleabnormalities]

Probable issue of mitochondrial DNA (not

a perfect match some mitochondrial DNAcomes from mother or oocyte )


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STEM CELLSUnspecialised cells with 2 special

properties

*Ability to differentiate into othercell type

*Ability to self regeneration


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STEM CELLS- contdserves as

*Building blocks of various organs and

tissues in the body*Sort of repair system for the body

*Breakthrough in the REGENERATIVE

MEDICINE


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STEM CELL HISTORY1998 - Researchers first extract stem cells from humanembryos

1999 - First Successful human transplant of insulin-makingcells from cadavers

2001 - President Bush restricts federal funding for embryonicstem-cell research

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

2003 - California okay stem cell research2004 - Harvard researchers grow stem cells from embryos

using private funding2004 - Ballot measure for $3 Billion bond for stem cells


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STEM CELLS

TOTIPOTENTCELLS

PLURIPOTENTCELLS

MULTIPOTENTCELLS


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TOTIPOTENT STEM CELLS UNLIMITED CAPABILITY

HUMAN CELLS DURING 1st FEW CELLDIVISIONS ALONE HAVE THIS POTENTIAL

FORM-EXTRA EMBRYONIC MEMBRANES

-TISSUES

-THE EMBRYO ITSELF-ALL POST EMBRYONIC TISSUES

-ORGANS


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PLURIPOTENT STEM CELLS

CAPABLE TO GIVE RISE TO MOST BUT NOT

ALL TISSUES OF AN ORGANISM

Eg. Inner cell mass


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Blastocyst Diagram

Princeton University


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Selection of embryonic stem cells


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Stem Cell Cultivation

University of Wisconsin-Madison


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STEM CELLS- SOURCES

ADULT

*Bone marrow

*MAPC (multipotent

adult progenitor cells)

*Hematopoietic cells

* CD34,CD133

*Umbilical cord, placenta

*menstrual blood

*Neural cells

*skin,liver

EMBRYO

*Primodial germ cells

* 5-9 wk oldembryo/fetus


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ADVANTAGES OF ADULT STEM

CELLSAUTOLOGOUS

NO TISSUE REJECTION

NO ETHICAL CONCERNS NO TERATOMAS

EASY TO OBTAIN [bonemarrow aspirate]

WIDELY AVAILABLE

GIVES RISE TO CELLS OF ALL GERM LAYERS


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DISADVANTAGES OF ADULT STEM

CELLS

Not as PLURIPOTENT as

EMBRYONIC STEM CELLS


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PROBLEMS WITH EMBRYONIC

STEM CELLS

REJECTION FORM TERATOMAS


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CORD BLOOD STEM CELLSContain all elements of blood- RBC, WBC, PLATELET, PLASMA

Increasingly used alternative to BM

Used to restore functional deficiencies

of several genetic and metabolicdiseases


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STEM CELL BANKINGSources cord blood ,- 60 to 80ml ,

umbilical cord 12cm

menstrual blood

Transported to CRYOCELL

Storage -196 degrees celcius for 21 yearsin liquid nitrogen


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MENSTRUAL BLOOD STEM CELLS High regenerative potential[6-7mm/ month] Rich source of self renewing cells Harvesting noninvasive, painless ,safe

MESENCHYMAL STEM CELLS under clinicaltrials

Therapeutic applications-copd-cardiac arrythmias-cns disorders-critical limb injuries-graft vs host disease


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TAKE HOME POINTS THERAPEUTIC CLONING RESEARCH gives

*better understanding of human developmentand stem cell research

* develop new treatment of presently incurablediseases in particular genetic ,serious injury

*enables perfectly match transplant tissue

*practical application not expected for atleast 10years


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THANK YOU

Cloning and Stem Cell Transfer

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