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URL: https://www.es-forum.com/Taurine-protects-against-Retinal-Ganglion-Cell-Degeneration-tp4023967.html

Incredible edible egg!!

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017

Taurine Provides Neuroprotection against Retinal Ganglion Cell Degeneration
Abstract <http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#top>

Retinal ganglion cell (RGC) degeneration occurs in numerous retinal
diseases leading to blindness, either as a primary process like in
glaucoma, or secondary to photoreceptor loss. However, no commercial drug
is yet directly targeting RGCs for their neuroprotection. In the 70s,
taurine, a small sulfonic acid provided by nutrition, was found to be
essential for the survival of photoreceptors, but this dependence was not
related to any retinal disease. More recently, taurine deprivation was
incriminated in the retinal toxicity of an antiepileptic drug. We
demonstrate here that taurine can improve RGC survival in culture or in
different animal models of RGC degeneration. Taurine effect on RGC survival
was assessed *in vitro* on primary pure RCG cultures under
serum-deprivation conditions, and on NMDA-treated retinal explants from
adult rats. *In vivo*, taurine was administered through the drinking water
in two glaucomatous animal models (DBA/2J mice and rats with vein
occlusion) and in a model of *Retinitis pigmentosa* with secondary RGC
degeneration (P23H rats). After a 6-day incubation, 1 mM taurine
significantly enhanced RGCs survival (+68%), whereas control RGCs were
cultured in a taurine-free medium, containing all natural amino-acids. This
effect was found to rely on taurine-uptake by RGCs. Furthermore taurine (1
mM) partly prevented NMDA-induced RGC excitotoxicity. Finally, taurine
supplementation increased RGC densities both in DBA/2J mice, in rats with
vein occlusion and in P23H rats by contrast to controls drinking
taurine-free water. This study indicates that enriched taurine nutrition
can directly promote RGC survival through RGC intracellular pathways. It
provides evidence that taurine can positively interfere with retinal
degenerative diseases.
*Citation: *Froger N, Cadetti L, Lorach H, Martins J, Bemelmans A-P, et al.
(2012) Taurine Provides




*Figure 5.
<http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042017?imageURI=info:doi/10.1371/journal.pone.0042017.g005>
Taurine
supplementation prevents RGC degeneration in glaucomatous Long-Evans rats
following episcleral vein occlusion.*


**


Taurine Reduces the Secondary RGC Degeneration Following Photoreceptor Loss
in P23H Rats


*Taurine was previously reported to prevent glutamate excitotoxicity in
embryonic cultured cerebellar neurons
[11]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-ElIdrissi1>or
mixed brain neurons
[10]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-Wu1>.
Our present study extends this conclusion to adult RGCs in NMDA-treated
retinal explants. *The intracellular effects of taurine discussed above
could explain this prevention of RGC glutamate excitotoxicity in
NMDA-treated retinal explants. Especially, the taurine-induced reduction of
intracellular Ca2+ levels, as described in brain neurons
[10]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-Wu1>,
[11]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-ElIdrissi1>and
in immortalized RGCs under hypoxia
[20]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-Chen1>,
could limit the toxic Ca2+ overload resulting from the prolonged activation
of the Ca2+-permeable NMDA receptors. The taurine-mediated reduction in
glutamate excitotoxicity could also be attributed to the taurine effect on
glutamate uptake
[31]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-Chen2>.
Despite the negative conclusion of the clinical trial with memantine, a
blocker of NMDA receptors
[32]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-DaneshMeyer1>,
glutamate excitotoxicity is considered as an important molecular mechanism
in RGC degeneration during glaucoma and other retinal diseases with an
ischemic contribution
[21]<http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0042017#pone.0042017-Seki1>.
Therefore, the protective effect of taurine on pure RGC cultures and on RGC
glutamate excitotoxicity could explain the *in vivo* RGC rescue in glaucoma
animal models.


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