Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

19.02.2009
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 was greater 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.

To find out more:

Firas Jammoul MD1,2, Qingping Wang MD1,2,3, Rima Nabbout MD4,5,6, Caroline Coriat MD1,2, Agnès Duboc PhD1,2, Manuel Simonutti1,2, Elisabeth Dubus1,2, Cheryl M. Craft PhD7, Wen Ye MD3, Stephen D. Collins MD PhD8 , Olivier Dulac MD4,5,6, Catherine Chiron MD4,5,6, José A. Sahel MD1,2,9,10, Serge Picaud PhD1,2,10,11
1 Inserm, U592, Institut de la Vision, Paris, France
2 Université Pierre et Marie Curie-Paris6, UMR-S 592, Paris, France ;3 Fudan University, Ophthalmology Department, Huashan Hospital, Shanghai, China
4 Inserm, U663, Paris, France
5 University Rene Descartes, Paris V, Paris, France
6 APHP, Hopital Necker, Service de Neuropédiatrie, Paris, France
7Ophthalmology and Cell & Neurobiology Departments, Keck School of Medicine of the University of Southern California, and The Mary D. Allen Laboratory for Vision Research, Doheny Eye Institute, Los Angeles, USA
8 Ovation Pharmaceuticals, Deerfield, USA
9 Centre Hospitalier National d'Ophtalmologie des quinze-vingts, Paris, France;
10Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
11Assistance Publique-Hopitaux de Paris, France
Annals of neurology DOI: http://dx.doi.org/10.1002/ana.21526
Published Online: 4 Feb 2009
Research contacts:
Serge Picaud
Institut de la Vision,
Email : serge.picaud@inserm.fr

Priscille Riviere | EurekAlert!
Further information:
http://www.inserm.fr

Further reports about: Epilepsy Heroin Inserm MD1 Sabril Taurine Vigabatrin amino acid cocaine methamphetamines retina cells taurine-rich diet

More articles from Health and Medicine:

nachricht World first: Massive thrombosis removed during early pregnancy
20.07.2017 | Universitätsspital Bern

nachricht Therapy of preterm birth in sight?
19.07.2017 | Universitätsspital Bern

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>