Skip to main content

be careful little eyes

Sooooo...

I'd be lying if I said the thought of Trevor losing vision (even if it is peripheral) as a result of trialing Vigabatrin didn't weigh heavy on my heart. I act flippant. But in reality I'm not. But trading cognition for vision? We chose the former.


But the study below may result in promising news for Vigabatrin trial-ees in the future!


Taurine: Key to the visual toxicity of an anti-epileptic drug for children?


Published: Wednesday, 18-Feb-2009


Child Health News


Vigabatrin (Sabril), first intention molecule for the treatment of epilepsy in children, in many cases produces secondary effects that lead to an irreversible loss of vision. Serge Picaud, head of research at Inserm, and his colleagues of the Institut de la Vision have just discovered the origin of this secondary effect and have proposed strategies for limiting it.

They have shown that vigabatrin provokes a marked decrease in the blood level in an amino acid, taurine, resulting in a degeneration of the retina cells induced by light. The researchers therefore suggest that exposure to light should be reduced and a
taurine-rich diet introduced in order to curb immediately these secondary effects in children undergoing treatment.

As for the validation of an alternative treatment associating vigabatrin and taurine, this will necessitate several years of development.This work is published in the review Annals of Neurology.

Epilepsy affects 1% of the world's population. With children, its treatment remains extremely restricted, and vigabatrin, (marketed in France under the name of Sabril), has obtained marketing authorisation for children aged under 2 years. This anticonvulsant, which is also administered to adults in the case of failure of other treatments, is at the same time now being evaluated for the treatment of addiction to heroin, cocaine and methamphetamines.

However, the serious secondary effects of this drug can induce an impairment of the
retina and a restriction of the visual field, noted, depending on the studies, in 10% to 40% of patients.In order to reach an understanding of this drug's modes of actions, and in particular the mechanism of visual function impairment, the Inserm researchers first of all administered vigabatrin to rats over a period of several months and analysed the influence of exposure to light during the treatment. The results show that there is no damage to the retina when the animals are kept in the dark throughout the treatment.Moreover, since previous work had shown that a deficiency of the organism in taurine (amino acid) triggers the degeneration of the photoreceptors (cells of the retina converting light into nervous signals), the researchers measured, in rodents, the plasma level of 19 amino acids. Whereas the concentration was identical for most of the amino acids in animals under vigabatrin and in non-treated rats, the taurine level turned out to be 67% lower in treated animals.

Taurine is essentially contributed by diet. By providing certain of the animals under treatment with a taurine supplementation, the researchers noted that their visual acuity wasgreater than that of the animals without supplementation. In addition, the amino acid doses administered to six children subject to regular attacks of epilepsy
and treated under vigabatrin reveal a taurine level that is far below the normal
values reported for children of the same age - and in some cases even
undetectable.

On the strength of these various tests, the scientists were able to prove that vigabatrin induces a pronounced reduction of the taurine level in the plasma. This marked fall is responsible for the degeneration of the photoreceptors and thus for the retinal toxicity in the animals exposed to light.

Pending confirmation in the human of the interest of providing patients under vigabatrin with a taurine supplementation, the researchers propose immediate solutions designed to limit the secondary effects in these patients.


"In the first instance, care should therefore be taken to ensure that patients
under vigabatrin consume a sufficient amount of food containing taurine. It is
also important that they should be exposed to as little light as possible (e.g.;
no night lights in a baby's bedroom at night) and should be induced to wear
sunglasses"
, says Serge Picaud.

The researchers also emphasise that any taurine supplementation must be subject to medical advice.

http://www.inserm

Comments

Anonymous said…
Just a quick comment. I haven't read the article yet, but I definitely plan to.

We're in a slightly strange situation where Emma doesn't have the best sight, but I would totally trade vision for cognition!!

But upon skimming the article, where do I find taurine? And how do I keep Emma in a dark room 24/7? ;)
Mrs. M said…
Very interesting!
Vig was our last option if R's current regime didn't work. I understand how that choice weighs on your heart. It's always about pros & cons isn't it? Weighing the options. Not easy, my friend.
Trevy will look so cute in sunglasses!:)
I have to admit that is the ONLY thing keeping us from trying it. i just don't know....
so are you supposed to keep the kids basically in the dark??? i just don't know if I could do it. the winter depressed me enough, imagine having to live in low light levels...ugghhhh. i may have to revisit the notion eventually though right now i just can't bring myself to do it. i agree that trevy would be just precious in sunglasses!!!

Popular posts from this blog

No, I don’t know him personally

  I’ve had several emails today asking if I know Mike W. of Marissa’s Bunny personally.    Trevy’s blog was linked on her site.  Although it’s not now.     I’ve posted here and there at his request.  Because…well…we’re a community.  Us IS families.  And Marissa is wicked cute.  Her daddy has a way with words.  Also who wouldn’t want the world to know about an iPad give-away?    But aside from that…I know about as much as you do.    We’ve never met in person.    Our only communication has been cyber.    I’m a ginormous sap and as such would love to believe that all is right.  That the sweet, beautiful families who were promised iPads will be getting them tonight.  Tomorrow at the latest.  That no one has been lied to.  That the personal thank you for your generosity email I sent him on behalf of other IS families I’ve grown to love and was thrilled to learn w...

the great answer hunt in the land of Infantile Spasms

If I've said it once... I've thought it a million times more. How it's like the more I research...and discover...about IS. The more blurry everything becomes. For every answer found. A dozen questions are unearthed. Remember our whole ARX saga ? Yeah...that threw me for a loop. So much so...that I never went on to post the end of the story. Thus far... See...the unbelievable in the world of genes happened. Because this is IS-ville after all. After Dr. Genes sampled Trevy's ARX gene on a whim...a whim which revealed an unkown (meaning the first time this specific change was found) mild mutation...she proceeded to send Toby's blood off to mad scientist central. With assurances that this was totally unnecessary . She was convinced that Trevor's ARX mutation was the underlying cause of his Infantile Spasms. And that Typical Toby...would prove to be just that. Typical...at least in all areas mutate-able. And yet...Toby's ARX blood sample revealed THE SAME MIL...

I sure hope...

they grow back curly! Saw the "unknown" flashing on the face of my cell phone and knew who it was. Who it had to be. Dr. Fellow. My eyes met Grams' and I nodded. Grams has a pool, see. For super hot days like today. We're also having a septic installed. Which meant no water or facilities at my place. But those weren't really the reasons I was there. Close to mom. The purple ringing thing in my hand was. Only I wasn't prepared for it to be ringing SO darn soon. Shortly after lunch instead of dinner! I swallowed. Took a deep breath. And clicked connect. Dr. Fellow has a very nice phone tone. Clear. Hint of compassion. If only a stitch of humor were added...it'd be heavenly. But there was no humor. Just business. He's very direct. I'm learning that about him. Which explains his short hello. Followed by immediately pushing into the news. Being that it was a unanimous consensus. The entire surgical committee feels Trevor is a good candidate. And then p...