The Vigabatrin Induced Retinal Toxicity is Associated with Photopic Exposure and Taurine Deficiency: An In Vivo Study

Abstract

Background/Aims: Retinal toxicity is one of the most commonly discussed and concerning adverse effects of vigabatrin (VGB). The present study explored the relationship between the VGB elicited retinal toxicity, photopic exposure, and taurine deficiency, aiming at screening for risk factors to minimize the adverse effects of VGB. Methods: The effects of VGB on function and morphology of mouse retinas were examined via a series of in vivo tests, including electroretinography (ERG), Spectral domain optical coherence tomography (SD-OCT), and optokinetic testing. Moreover, VGB-treated mice were in addition treated with taurine to verify possible protective effects against retinal toxicity. Results: A close relationship between VGB induced retinal toxicity and light exposure was observed. The VGB-treated mice which were reared in darkness preserved better visual function and retinal architectures as verified by the optokinetic tests, OCT and ERG examinations. The retinal taurine level of the VBG-treated mice which were exposed to light were significantly lower than that of the VBG mice reared in darkness. Furthermore, several in vivo evidence provided by our research confirmed that the VGB induced morphological and functional impairments could be partially alleviated by taurine treatment. The present study showed the retinal toxicity of VGB by in vivo measurements. Conclusion: The VGB induced retinal toxicity is closely associated with photopic exposure and taurine deficiency. Patients who are taking VGB might benefit from minimization of light exposure and dietetic taurine supplements.

Taurine Depletion Causes ipRGC Loss and Increases Light-Induced Photoreceptor Degeneration

“…49 The effect of this type of light on the retina and the intrinsic and extrinsic factors that may modify this response are at present not known, but it has been postulated that they may worsen retinal degenerations, especially in conditions of low plasma taurine levels, such as in vigabatrin-induced retinal toxicity. 4,10 In this study, rings devoid of cones were observed ALE both in control and in taurine-depleted animals mainly in an ''arciform'' area of degeneration located in the dorsal retina. In previous works, we have described this ''arciform area'' [18][19][20] as the area with maximal photoreceptor loss and vascular leakage of horseradish peroxidase immediately ALE.…”

“…This suggests that taurine supplementation may be beneficial to prevent retinal degenerations that proceed with photoreceptor or RGC loss and in which light may also be a critical etiologic factor, such as inherited retinal degeneration, AMD, or glaucoma. 10,22,95,96 Finally, our data also suggest that taurine supplementation may be beneficial to prevent retinal degenerations in which S-cone degeneration is the initial event, such as the photoreceptor degenerations that are initiated or worsened by light.…”

“…7,8 Moreover, we have shown that epileptic patients treated with vigabatrin show insufficient taurine plasma levels, 9 and, recently, it has been proposed that this deficit together with photopic exposure could be the cause of vigabatrin-induced retinal toxicity. 4,10 In accordance, taurine supplementation has been recommended to avoid retinal damage in human patients treated long-term with vigabatrin.…”

“…6 Several authors have suggested a direct relationship between taurine depletion and light sensitivity of retinal neurons. 6,10,[15][16][17] Thus, the question arises whether retinal degeneration triggered by taurine depletion is greater after light exposure (ALE).…”

Taurine Protects Mouse Spermatocytes from Ionizing Radiation-Induced Damage Through Activation of Nrf2/HO-1 Signaling

“…Taurine, as an endogenous antioxidant and a scavenger of the hydroxyl radical, may play a part in treating toxicity mediated by oxygen radical [23]. Many studies have demonstrated that Taurine has several pharmacological and biological properties including antioxidant, anti-fibrotic and elicited retinal toxicity [24, 25]. In addition, study has been reported taurine can be involved in male reproductive organs [26] and act as an antioxidant of sperm [27].…”