Introduccion a fisiologia del sn - FISIOPATOLOGIA II, PARCIAL 1

TEMÁTICAS

INTRODUCCIÓN AL

SISTEMA

NERVIOSO Por:

Dr. Winston Mejía

M.Sc.P.H.

Salubrista Toxicólogo

What are Stem Cells?

• Master cells that can give rise to the 210 different types of tissue in the human body.

• They have the ability to divide for an indefinite period of time.

Traditional Stem Cell Types

• Totipotent – Can become an entire human

being.

• Pluripotent– Can develop into any body cell.

• Multipotent– Thought only to differentiate into

cells of same tissue type.

Sources of Stem Cells

• Embryo

• Fetus

• Umbilical

Cord

• Placenta

• Adult

Tissues

Embryonic Stem Cells

Human Embryo

• Difficult to establish and maintain.

• Difficult to get pure culture

• Tumor formation• Genomic

instability• Difficult to control

differentiation.• Function

abnormalities• Few successes in

animals• No current clinical

treatments

Embryonic Stem Cell Therapy Will Likely

Require Human Cloning

• To get compatible cells.

• Still would be rejected

• If worked, would require 850 million eggs.

Cloning Puts Women at Risk

• Example - 17 million diabetics in U.S.– Collecting 10 eggs/donor– Generous 20% cloning success to

blastocyst• Animals 1-3%

– Generous 10% efficiency to ES culture

– Requires minimum of 850 million eggs and 85 million women. There are 55 million women of child bearing age in U.S.

– Exploitation and health risk for women.

Many Sources of Adult Stem Cells

• Bone marrow

• Fat • Brain• Skin• Lung• Liver• Pancreas• Breast • Tooth

pulp• Blood

MuscleMuscle SalivarySalivary CorneaCornea Tendon Tendon CartilageCartilage ThymusThymus SynoviumSynoviumUmbilical Umbilical

cordcordPlacentaPlacenta

Multipotent Adult Progenitor Cells

( MAPC’s)• From Bone

Marrow• Reliably from

70% of bone marrow donors

• Differentiated into all tissue types

• Do not form tumors– Reyes M, Lenvik T,

Lund T, Aguiar D, Koodie L, Verfaillie CM. Purification and ex vivo expansion of post-natal human marrow mesodermal progenitor cells. Blood 98: 2615-75, 2001.

Adult Stem Cells• Pluripotency

– Marrow -> heart, liver, fat, skin, bone, fat, brain, nerve, tendon, retina, ALL TISSUES

– Muscle -> bone, cartilage, heart

– Brain -> eye, blood, muscle

– Fat -> muscle, neurons, bone

– Pancreas -> liver, islet cells

– Placenta ->bone,nerve, cartilage, muscle, tendon, etc

• Long life span

• Easier to culture or mobilize

• Histocompatibility

• Biosafety

The Underlying Question: “What is a

person?”

Any Any living living being being

of of human human origin origin is a is a

person.person.

Personhood Begins at Fertilization

• Continuous self directed growth begins at fertilization.

• No relevant break.

• Humans maintain ontological identity.

• Personhood does not depend on abilities but essence or nature.

Other Ethical Arguments for Personhood

• There is an inherent right to life.

• The ethical principle of autonomy prohibits depriving someone of life.

• If personhood is “bestowed,” it can be taken away.

• Harmful research prohibited

Embryonic Stem Cell Research

Is immoral since it destroys

human beings at their

earliest stages of

development.

BUENAS PRÁCTICAS CLÍNICAS: Documento

de las Américas

IV CONFERENCIA PANAMERICANA PARA LA ARMONIZACIÓN DE LA REGLAMENTACIÓN FARMACÉUTICA

República Dominicana2-4 Marzo 2005