Hier noch eine weiterer interessanter Artikel den ich heute per Mail bekommen habe. An einer medizinischen Hochschule in Huston/Texas werden bereits Versuche mit Stammzellen zur Wiederherstellung des Gehörs an Menschen (Kleinkindern) gemacht. Der Text ist leider auch in Englisch.
Ich stelle ihn trotzdem mal ein:
Human Hair Cell Regeneration Clinical Trial Using Stem Cells
Begins
by Neil Bauman, Ph.D.
Research into regenerating human hair cells in the inner ear, with
the aim of restoring hearing, has been ongoing for a number of
years. Researchers have been trying, with varying degrees of
success, to get hair cells to regenerate in animals--but there are
still many hurdles to overcome. Consequently, human trials
appear to still be a number of years away.
However, one method has just leapfrogged the competition and
has already begun a Phase I clinical trial. (Note: a Phase I
clinical trial is done on a very small group of people [in this case
10] to see if the proposed treatment will be safe and identify any
resulting side effects. It's not till Phase II trials that researchers
primarily determine just how effective the treatment will be,
although preliminary results hopefully will come out of the Phase I
trials.)
This Phase I clinical trial is very limited in scope--just for children
between the ages of 6 weeks and 18 months who have an
acquired (but not genetic) moderate to profound sensorineural
hearing loss since birth, and who have had their umbilical cord
blood saved by the Cord Blood Registry.
The idea behind this trial is that there are progenitor stem cells
floating around in the umbilical cord blood that researchers want
to use in this trial. You see, when some babies are born, doctors
extract and save the blood left in a baby's umbilical cord for use
later in the same baby if the baby ever needs it. The fancy name
for this is "autologous human umbilical cord blood". Using the
baby's own blood guarantees that the baby's immune system
won't reject the blood when it is intravenously injected back into
the child at some time in the future.
In this trial, researchers will intravenously inject the stored blood
back into the same young child that originally "donated" it. What
they expect to happen is that the hemopoietic [hee-moe-poy-
ET-ik] stem cells [stem cells that make blood cells] still floating
around in this umbilical cord blood will make their way to the inner
ear where they will become involved in replacing and repairing
any damaged hair cells. The hope is that this will ultimately
restore some degree of hearing.
As the clinical trial prospectus states: "Pre-clinical data suggest
progenitor cell infusions may enhance intrinsic repair mech-
anisms in the Organ of Corti which may restore hair cells. This
treatment could ultimately lead to hearing improvement. Human
umbilical cord blood is an available, autologous, stored progenitor
cell population available for potential therapeutic use." (1)
This clinical trial began earlier this year at the Children's
Memorial Hermann Hospital in Houston, TX, and is estimated to
be completed by April of 2015.
Results from previous studies using mice showed that cochlear
regeneration occurred. "Our findings show dramatic repair of
damage with surprisingly few human-derived cells having
migrated to the cochlea," said Roberto P. Revoltella, MD, PhD,
lead author of one such study. "A fraction of circulating
hemopoietic stem cells fused with resident cells, generating
hybrids, yet the administration of hematopoietic stem cells
appeared to be correlated with tissue regeneration and repair as
the cochlea in non-transplanted mice remained seriously
damaged." (2)
The mice in these studies had had their hearing damaged by
either loud noise or by ototoxic drugs. Interestingly enough,
cochlear regeneration was less successful in the group
deafened by noise than in the group deafened by ototoxic drugs,
implying that damage was more severe when induced by noise.
Furthermore, regenerative effects were greater in mice injected
with a higher number of hematopoietic stem cells. Researchers
also found that regeneration of cochlear tissues improved as
time passed. (2)
In another year or two, we should know whether this method of
restoring hearing (to some degree or other since it obviously
wasn't 100% in the animal studies) will work on young children.
______________
(1) Safety of Autologous Human Umbilical Cord Blood
Mononuclear Fraction to Treat Acquired Hearing loss in
Children. 2011.
http://clinicaltrials.gov/ct2/show/NCT0 ... d=%22Heari
ng+Loss%22&rank=16 (or
http://tinyurl.com/3kcgc26 if the above
link is broken).