●
It can give specialized
cells by cellular differentiation
●
It can be renewed
many times.
We
find them for the greater part at the embryonic stage and also in an
adult stage.
The main sources are, embryos,
the blood
of umbilical cord
and in the marrow.
They have a very important role in the development
of organisms as well as in their preservation.
Stem cells are elements which arouse the biggest interest of the
researchers in the medical domain, because the cellular therapy can
resolve a lots of diseases.
The
researches consists in reproducing tissues, organs, neurones etc.
From these stem cells which are capable of giving every types of
cells, we can transplant marrow and cure other specific diseases of
the blood and some cancers type, but also to restore a new skin to a
big burnt person.
But
with progress, we will be able to resolve the problem of organ
transplants (domain in which organs are missing), neurodegenerative
diseases (Parkinson, Alzheimer, Huntingthon, etc.) by making new
neurones, and many others organs.
However,
problems are numerous :
●
The most interesting stem cells (those who can differ in any tissue)
are at the embryonic stage, who raises ethical
problems.
●
We still don't master totally the phenomenon of differentiation
of cells.
●
But especially the transplant consists in replacing an organ by
importation of a new one. It provoke the immune system problems.
Indeed organs can be recognized as foreign organisms and all the
immunizing machinery starts. We call the phenomenon “rejection of a
transplant”, the transplant is destroyed and side effects can also
appear.
However,
reproduction of an organ from our own stem cells could resolve this
problem of rejection what stimulates researches, but still pose
ethical problems : We can keep the blood of cordon, but its
preservation is paying, everybody will have no same right for the
health according to our income.
Fanny.B
Aucun commentaire:
Enregistrer un commentaire